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Title:
ANTIPOLYMERANT COMPOSITIONS WITH NAPHTHOQUINONE AND HYDROXYLAMINE AND METHODS OF USING
Document Type and Number:
WIPO Patent Application WO/2024/081354
Kind Code:
A1
Abstract:
Described are compositions and methods for inhibiting and retarding polymerization of a monomer composition, which use a naphthoquinone and a hydroxylamine. When present in a monomer-containing composition, the combination of the naphthoquinone and hydroxylamine provides an unexpected beneficial antipolymerant effect inhibiting unwanted formation of fouling polymer. The antipolymerant combination can be added to a hydrocarbon composition, such as a petroleum, that can include a polymerizable components, such as styrene, where the hydrocarbon composition is purified or processed, such as in the case of distillation.

Inventors:
MASERE JONATHAN (US)
DHAWAN ASHISH (US)
SILVERNAIL CARTER M (US)
CAMPOS PEDRO CARVALHO (PT)
Application Number:
PCT/US2023/035016
Publication Date:
April 18, 2024
Filing Date:
October 12, 2023
Export Citation:
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Assignee:
ECOLAB USA INC (US)
International Classes:
C07C7/20; C07C15/46; C07C49/653; C07C67/58
Domestic Patent References:
WO2020014606A12020-01-16
WO2020068735A12020-04-02
Foreign References:
US6706209B12004-03-16
US4003800A1977-01-18
US5583247A1996-12-10
US7045647B22006-05-16
US11312792B22022-04-26
Attorney, Agent or Firm:
WEAVER, Paul, L. et al. (US)
Download PDF:
Claims:
What is claimed is:

1. A method for reducing the formation of polymer in a monomer-containing composition, the method comprising adding to a composition comprising a polymerizable monomer or a compound capable of forming a polymerizable monomer components comprising: a naphthoquinone, and a hydroxylamine of

Formula I: HO-NR'R2, wherein at least one or both of R1 and R2 is or are a carbon- containing group having 1-12 carbon atoms, optionally substituted with one or more hydroxyl groups, wherein R1 or R2 is -H if not the carbon-containing group; or of

Formula II: wherein X is -(CHR5)W-, wherein R5 is selected from the group consisting of -FI, R3, and R4, R3 is selected from -H and alkyl, and R4 is selected from -H and -OH, y is 0 or an integer in the range of 1-3, z is 0 or an integer in the range of 1-3, and w is an integer in the range 1 -4, wherein the naphthoquinone and hydroxylamine reduces formation of polymer in the composition.

2. The method of claim 1, wherein R1 is selected from (i) C1-C12 alkyl groups, (ii) C 1 -C8 alkyl groups, or (iii) C1 -C6 alkyl groups, wherein (i)-(iii) are linear, branched, or cyclic alkyl groups, or combinations thereof; and R2 is selected from (iv) -H and Cl -Cl 2 alkyl groups, (v) -H and C1-C8 alkyl groups, or (vi) -H and C1-C6 alkyl groups, wherein the alkyl groups of (iv)-(vi) are linear, branched, or cyclic, or combinations thereof, and wherein any one or more alkyl groups of (i)-(vi) are optionally substituted with one or more hydroxyl groups.

3. The method of claim 2 wherein R1 is selected from (A) methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, cyclopentyl, isopentyl, neopentyl, hexyl, cyclohexyl, 1-, 2-, and 3-methylbutyl, 1,1-, 1,2-, or 2,2-dimethylpropyl, 1-ethyl- propyl, 1-, 2-, 3-, or 4-methylpentyl, 1,1-, 1,2-, 1,3-, 2,2-, 2,3-, or 3,3-dimethylbutyl, 1- or 2-ethylbutyl, 1 -ethyl- 1 -methylpropyl, and 1,1,2- or 1,2,2-trimethylpropyl, and methylcyclopentyl, and R2 is selected from (A) and -H, wherein any of (A) are optionally substituted with one or more hydroxyl groups..

4. The method of claim 3 wherein the compound of Formula I is selected from the group consisting of N,N-dimethylhydroxylamine, N-methyl-N-ethylhydroxylamine, N-methyl- N-propylhydroxylamine, N-methyl-N-isopropylhydroxylamine, N-methyl-N- propylhydroxylamine, N-methyl-N-butylhydroxylamine, N-methyl-N- isobutylhydroxylamine, N-methyl-N-t-butylhydroxylamine, N-,N-diethylhydroxylamine, N-ethyl-N-propylhydroxylamine, N-ethyl-N-isopropylhydroxylamine, N-ethyl-N- propylhydroxylamine, N-ethyl-N-butylhydroxylamine, N-ethyl-N-isobutylhydroxylamine, N-ethyl-N-t-butylhydroxylamine, N-,N-dipropylhydroxyIamine, N-,N- diisopropylhydroxylamine, N-propyl-N-butylhydroxylamine, N-isopropyl-N- butylhydroxylamine, N-propyl-N-isobutylhydroxylamine, N-propyl-N-t- butylhydroxylamine, N-ispropyl-N-isobutylhydroxylamine, and N-isopropyl-N-t- butylhydroxylamine.

5. The method of claim 3 wherein the compound of Formula 1 is selected from the group consisting of N-methylhydroxylamine, N-ethylhydroxy famine, N-propylhydroxylamine, N-isopropylhydroxylamine, N-butylhydroxylamine, N-isobutylhydroxylamine, N-t- butylhydroxylamine, N-sec-butylhydroxylamine, N-pentylhydroxylamine, N-cyclo- pentylhydroxylamine, N-isopentylhydroxylamine, N-neopentylhydroxylamine, N- hexylhydroxylamine, N-cyclohexylhydroxylamine, N-1-, 2-, and 3-methylbutylhydroxyl- amine, N-l ,1 1 ,2-, or 2,2-dimethylpropylhydroxylamine, N-l-ethyl-propylhydroxyl- amine, 1-, 2-, 3-, or 4-methylpentylhydroxylamine, N-1,1-, 1,2-, 1,3-, 2,2-, 2,3-, or 3,3- dimethylbutylhydroxylamine, N-l- or 2-ethylbutylhydroxylamine, N-l -ethyl- 1 -methylpropylhydroxylamine, and N-l , 1 ,2- or 1,2,2-trimethylpropylhydroxylamine, and N- methylcyclopentylhydroxylamine.

6. The method of claim 3 wherein the compound of Formula I is selected from the group consisting of N-hydroxymethylhydroxylamine, N-1-, or 2-hydroxyethylhydroxylamine, N- 1-, 2- or 3-hydroxypropylhydroxylamine, N-1-, or 2-hydroxypropylhydroxylamine, N-1-, 2-, 3-, or 4-hydroxybutylhydroxylamine, N-1-, 2- or 3-hydroxy isobutylhydroxylamine, N-

1-, 2- or 3-hydroxysecbutylhydroxylamine, N-2-hydroxy-t-butylhydroxylamine, and N-1-,

2-, 3-, 4, or 5-N-hydroxypentylhydroxylamine; or is selected from the group consisting of N,N-bis(hydroxymethyl)hydroxyIamine, N,N-bis(l-, or 2-hydroxyethyl)hydroxylamine, N,N-bis(l-, 2- or 3-hydroxypropyl)hydroxylamine, N,N-bis(l-, or 2-hydroxypropyl) hydroxylamine, N,N-bis(l-, 2-, 3-, or 4-hydroxybutyl)hydroxylamine, N,N-bis(l-, 2- or 3- hydroxyisobutyl)hydroxylamine, N,N-bis(l-, 2- or 3-hydroxysecbutyl)hydroxylamine, N,N-bis(2-hydroxy-t-butyl)hydroxylamine, and N,N-bis(l-, 2-, 3-, 4, or 5-N- hydroxypentyl)hydroxylamine.

7. The method of claim 1 wherein the one or both of R1 and R2 that is the carbon- containing group having 1-12 carbon atoms comprises an aryl group, optionally where one or both of R1 and R2 are of the formula: wherein R6 is independently selected from the group consisting of -H, -OH, and alkyl, wherein v is an integer in the range of 1-6, R7 is independently selected from the group consisting of -H, -OH, and alkyl, wherein q is an integer in the range of 1-5.

8. The method of claim 7, claims wherein formula:

R6 is independently selected from -H and -OH, v is an integer in the range of 1-4, R7 is -H and q is 5, wherein the compound is optionally selected from the group consisting of benzylhydroxylamine, N-phenethyl- hydroxylamine, N-(3-phenyl-propyl)-hydroxylamine, N-(4-phenyl-butyl)-hydroxylamine, N-(5-phenyl-pentyl)-hydroxylamine, N-(6-hexyl-propyl)-hydroxylamine, N-(3-phenyl-2- methyl-propyl)-hydroxylamine, and N-(4-phenyl-3-methyl-butyl)-hydroxylamine; selected from the group consisting of dibenzylhydroxylamine, N,N-bis(phenethyl) hydroxylamine, N,N-bis(3-phenylpropyl)hydroxylamine, N,N-bis(4-phenyl-butyl)- hydroxylamine, N,N-bis(5-phenyl-pentyl)-hydroxylamine, N,N-bis(6-hexyl-propyl)- hydroxylamine, N,N-bis(3-phenyl-2-methyl-propyl)-hydroxylamine, and N,N-bis(4- phenyl-3-methyl-butyl)-hydroxylamine; selected from the group consisting of N-(2-pheny 1-1 -hydroxy 1- ethyl)hydroxylamine, N-(3-phenyl-2-hydroxyl-propyl)-hydroxylamine, N-(4-phenyl-2- hydroxyl-butyl)-hydroxylamine, N-(5-phenyl-2-hydroxyl-pentyl)-hydroxylamine, N-(6- hexy!2-hydroxyl— propyl)-hydroxylamine, selected from the group consisting of N,N-bis(2-phenyl-l-hydroxyl- ethyl)hydroxylamine, N,N-bis(3-phenyl-2-hydroxyl-propyl)-hydroxylamine, N,N-bis(4- phenyl-2-hydroxyl-butyl)-hydroxylamine, N,N-bis(5-phenyl-2-hydroxyl-pentyl)- hydroxylamine, and N,N-bis(6-hexyl2-hydroxyl— propyl)-hydroxylamine.

9. The method of any one of the previous claims wherein the naphthoquinone is 1 ,4- naphthoquinone, 1,3 -naphthoquinone, or 1 ,2-naphthoquinone.

10. The method of any one of the previous claims, wherein the naphthoquinone is an aminated naphthoquinone antipolymerants selected from the group consisting of 2- amino, 1 ,4-naphthoquinone, 2,3-diamino, 1 ,4-naphthoquinone, 2-amino, 1 ,3- naphthoquinone, 4-amino, 1,3 -naphthoquinone, 2,4-diamino,l ,3 -naphthoquinone, 3- amino,l ,2-naphthoquinone, 4-amino, 1,2-naphthoquinone, and 3,4-diamino,l,3- naphthoquinone.

11 . The method of any one of the previous claims wherein the polymerizable monomer comprises a vinyl or ethylenically unsaturated group.

12. The method of claim 1 1 wherein the polymerizable monomer is selected from the group consisting of acrylic acid, acrylonitrile, alkylated styrene, butadiene, chloroprene, divinylbenzene, ethyl acrylate, ethyl methacrylate, isoprene, methacrylic acid, methyl methacrylate, methyl acrylate, a-methylstyrene, methacrylonitrile, styrene, styrene sulfonic acid, vinyltoluene, and vinylpyridine.

13. The method of any one of the previous claims wherein the composition includes one or more non-polymerizable hydrocarbons.

14. The method of any of one of the previous claims wherein the naphthoquinone is present in the composition in an amount in the range of 50 to 500 ppm, and the hydroxylamine is present in the composition in an amount in the range of 50 to 500 ppm, optionally wherein the naphthoquinone is present in the composition in an amount in the range of 75 to 400 ppm, and the hydroxylamine is present in the composition in an amount in the range of 75 to 400 ppm, optionally wherein the naphthoquinone is present in the composition in an amount in the range of 100 to 300 ppm, and the hydroxylamine is present in the composition in an amount in the range of 100 to 300 ppm, optionally wherein the naphthoquinone is present in the composition in an amount in the range of 150 to 250 ppm, and the hydroxylamine is present in the composition in an amount in the range of 150 to 250 ppm.

15. The method of any one of the previous claims wherein adding is performed during purification or processing of one or more hydrocarbon components of the composition.

16. The method of claim 15 wherein processing of the one or more hydrocarbons comprises a distillation step.

17. The method of any one of the previous claims which is performed prior to storage or transport of the composition.

18. The method of any one of the previous claims wherein the naphthoquinone is used at a first concentration, and the hydroxylamine is used at a second concentration, wherein the first and second concentrations together are a total concentration, and the combination of the naphthoquinone and hydroxylamine together provide a level of polymer formation that is lower than the level of polymer formation observed when either the naphthoquinone and hydroxylamine are used alone at the total concentration, or at the average of the levels of polymer formation of the naphthoquinone and hydroxylamine when used alone at the total concentration.

19. The method of claim 18, wherein the combination of the hydroxylamine and naphthoquinone provides a reduction in polymerization of 10% or greater, 20% or greater, 30% or greater, 40% or greater, 50% or greater, 60% or greater, 70% or greater, or 80% or greater, such as up to about 90 % or greater, or a reduction in an % amount in the range of any of these numbers, as compared to the average, or as compared to either the of naphthoquinone and hydroxylamine used individually at the total concentration.

20. An additive composition for inhibiting the polymerization of monomers, the composition comprising: a naphthoquinone, and a hydroxylamine of

Formula T: IIO-NR' R2, wherein at least one or both of R1 and R2 is or are a carbon- containing group having 1-12 carbon atoms, optionally substituted with one or more hydroxyl groups, wherein R1 or R2 is -H if not the carbon-containing group; or of

Formula 11: wherein X is -(CHR5),,-, wherein R5 is selected from the group consisting of -H, R3, and R4, R3 is selected from -H and alkyl, and R4 is selected from -Fl and -OH, y is 0 or an integer in the range of 1-3, z is 0 or an integer in the range of 1-3, and w is an integer in the range 1 -4.

21. The composition of claim 20 further comprising an organic solvent.

22. The composition of claim 21 wherein the naphthoquinone is in an amount in the range of 5 to 45% (wt); the hydroxylamine is in an amount in the range of 5 to 45% (wt); and the organic solvent is in an amount in the range of 10 to 90% % (wt).

23. The composition of claim 22 wherein the naphthoquinone is in an amount in the range of 15 to 35% (wt); the hydroxylamine is in an amount in the range of 15 to 35% (wt); and the organic solvent is in an amount in the range of 30 to 70% (wt).

24. Use of a composition according to any one of claims 20-23 for reducing formation of polymer in a composition.

25. Use of a composition according to any one of claims 20-23 for a hydrocarbon refining or a hydrocarbon purification process.

26. Use of a composition according to any one of claims 20-23 for storage or transport of a hydrocarbon composition.

Description:
ANTIPOL YMERANT COMPOSITIONS WITH NAPHTHOQUINONE AND HYDROXYLAMINE AND METHODS OF USING

TECHNICAL FIELD

[ 1 ] The invention is directed to compositions and use of a naphthoquinone in combination with a hydroxylamine for reducing the formation of polymers in a monomer- containing composition.

BACKGROUND

[2] Ethylenically unsaturated monomers, such as vinyl aromatic monomers like styrene, can be present in processing streams or in refined products made by various chemical industrial processes. However, these monomer types may undesirably polymerize through radical polymerization especially at elevated temperature. As a result, solid deposits of polymer can form on the surface of the process equipment during industrial manufacture, processing, handling, or storage. The resulting polymers can be problematic and lead to equipment “fouling” and product contamination. Accordingly, this can necessitate treating the apparatus to remove the polymer, or may necessitate processing steps that require shutting down operations to physically or mechanically remove. Equally important, the polymer material contaminates processed streams thereby necessitating steps to remove said contaminants from compositions streams or stored compositions. Consequently, these undesirable polymerization reactions result in a loss in production efficiency because they consume valuable reagents and additional steps may be required to clean equipment and/or to remove the undesired polymers. Undesired polymerization reactions are particularly problematic in compositions having vinyl aromatic monomers.

[3] To minimize undesired polymerization reactions, compounds that act as antipolymerants are often added to process streams or stored compositions. Two categories of antipolymerants have been developed to minimize unwanted polymerization reactions: polymerization inhibitors and polymerization retarders.

[4] Polymerization inhibitors inhibit polymerization reactions from occurring. However, these compounds are generally consumed rapidly. For example, in cases of emergency due to mechanical or processing problems, and where more inhibitor cannot be added, previously added inhibitor will be rapidly consumed. Subsequently, unwanted polymerization reactions will then rapidly recur. [5] Polymerization retarders, while they slow down the rate of polymerization reactions, are not as effective as polymerization inhibitors. Polymerization retarders, however, are usually not consumed as quickly as polymerization inhibitors so they tend to be more useful in cases of emergency shutdown of operations.

[6] Retarders such as sulfur and dinitrophenol (DNP) compounds such as 2,6- dinitrophenol, 2,4-dinitrocresol, and 2-sec-butyl-4,6-dinitrophenol (DNBP) have found use in antipolymerant methodologies. However, DNP and sulfur retarders release NOxand SOx gases, making their use problematic. Furthermore, DNP-based retarders are highly toxic, which is a concern during handling.

[7] Another class of compounds designed to function as a safer substitute for DNP retarders is based on quinone methide chemistry. Quinone methides slow the rate of polymer formation under static conditions and do not need to be frequently re-fed into the process stream, but some quinone methide compounds do not exhibit good stability.

Examples of quinone methide compounds are in U.S. Pat. Nos. 4,003,800, 5,583,247, and 7,045,647.

[8] Another chemistry used for antipolymerant technologies for high-temperature processing of vinylic monomers is 4-hydroxy-2,2,6,6-trimethyl (HTEMPO). Though effective, HTEMPO and its derivatives are efficient inhibitors, but are not effective retarders.

[9] Technical challenges remain in this area of technology relating to efficacy of polymerization inhibitors and retarders, as well as stability and safety concerns. Further, the disclosure is associated with the finding that while desirable to combine polymerization inhibitors and retarders in the same composition, mixtures often suffer from compatibility issues which reduce effectiveness of both the inhibitor and the retarder activities.

[10] Realizing issues associated with the current state of the art of antipolymerants, the current technology of the application relates to a combination composition that is safer and efficacious as an antipolymerant in general and, a retarder in particular.

SUMMARY

[11] Disclosed herein are compositions and methods for reducing formation of polymers in a composition that includes or that can form monomers. Methods of the disclosure use a naphthoquinone and a hydroxylamine as a combination antipolymerant formulation which demonstrates an unexpected beneficial antipolymerant effect, such as a synergistic antipolymerant effect, when used together. The mixture of naphthoquinones and a hydroxylamine can provide excellent activity in inhibiting unwanted polymerization of monomers such as styrene in various applications, such as in synthesis, refinement, or storage. By using the inventive combination naphthoquinone and hydroxylamine, polymer contamination can be reduced and additional processing steps can be minimized or avoided. In addition, by functioning to inhibit and retard polymerization, the mixture can minimize buildup of unwanted polymer on processing or storage apparatus (“fouling”), and accordingly reduce maintenance costs of such equipment. Moreover, the inventive combination allows the reduction of reagents added to the treated (e.g., hydrocarbon) composition providing higher levels of purity of refined products and reducing overall costs of the product, as well as costs associated with its production. Further, the inventive combination can avoid use of other antipolymerant compounds that are unsafe for use, costly, that have poor effectiveness, or combinations thereof.

[ 12] Also, in certain embodiments, the naphthoquinone and hydroxylamine can advantageously be combined in a single package formulation for addition to a composition which can include, or can form monomer, wherein the combination demonstrates an unexpected beneficial antipolymerant effect, such as a synergistic antipolymerant effect, in use.

[13] In embodiments, the disclosure provides a method for inhibiting the polymerization of monomers in a monomer-containing composition. The method includes a step or steps of adding components that include a naphthoquinone and a hydroxylamine to a composition that is capable of forming a polymerizable monomer. The hydroxylamine is of Formula I which is: HO-NR'R 2 , wherein at least one or both of R 1 and R 2 is or are a carbon-containing group having 1-12 carbon atoms, optionally substituted with one or more hydroxyl groups, wherein R 1 or R 2 is -H if not the carbon- containing group; or of Formula II which is: wherein X is -(CHR 5 ) W -, wherein R 5 is selected from the group consisting of -H, R 3 , and R 4 , R 3 is selected from -H and alkyl, and R 4 is selected from -H and -OFI, y is 0 or an integer in the range of 1-3, z is 0 or an integer in the range of 1 -3, and w is an integer in the range 1-4. Present in the composition, the naphthoquinone and hydroxylamine inhibit the polymerization of the polymerizable monomer.

[14] Exemplary naphthoquinones include 1,4-naphthoquinone, 1,3 -naphtho quinone, 1 ,2-naphthoquinone, and derivatives thereof, such as aminated derivatives of naphthoquinone.

[15] In exemplary embodiments, the method can include adding the naphthoquinone and hydroxylamine components to a hydrocarbon composition, such as a hydrocarbon composition that is subjected to purification or processing of one or more hydrocarbon components of the composition. The hydrocarbon composition can be derived from a petroleum material and can include a polymerizable components such as styrene, or one or more components capable for forming a polymerizable component. For example, the naphthoquinone and hydroxylamine components can be added to a hydrocarbon composition undergoing a distillation step, or can be added to a refined composition prior to its storage or transport.

[16] In other embodiments, the disclosure provides an additive composition that includes the naphthoquinone, the hydroxylamine, and a suitable solvent or solvent system. The naphthoquinone and the hydroxylamine can be present in predetermined concentrated amounts in the additive composition so that when it is added to a monomer-containing composition, the concentrated amounts are diluted to working amounts that act in an unexpected (e.g., synergistic) manner to inhibit monomer polymerization.

DESCRIPTION OF THE DRAWINGS

[17] Figure 1 is a graph of the formation of polystyrene in a styrene monomer solution over time in the presence of N,N-diethylhydroxylamine (DEHA) at 400 ppm, 1,4- naphthoquinone (1,4-NQ) at 400 ppm, the combination of DEHA and 1,4-NQ, each at 200 ppm, and 2,4-dintro-6-sec-butylphenol (DNBP) at 400 ppm.

[18] Figure 2 is a graph of the formation of polystyrene in a styrene monomer solution over time in the presence of at 400 ppm, 1 ,4-NQ at 400 ppm, the unexpected (e.g., synergistic) combination of and 1,4-NQ, each at 200 ppm, and DNBP at 400 ppm .

[19] Figure 3 is a graph of the formation of polystyrene in a styrene monomer solution over time in the presence of dibenzylhydroxylamine (DBzHA) at 400 ppm, 1 ,4-NQ at 400 ppm, the unexpected (e.g., synergistic) combination of DBzHA and 1,4-NQ, each at 200 ppm, and DNBP at 400 ppm. DETAILED DESCRIPTION

[20] Although the present disclosure provides references to preferred embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. Reference to various embodiments does not limit the scope of the claims attached hereto. Additionally, any examples set forth in this specification are not intended to be limiting and merely set forth some of the many possible embodiments for the appended claims.

[21] Additional advantages and novel features of the invention will be set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned through routine experimentation upon practice of the invention.

[22] The disclosure provides methods and compositions that use a naphthoquinone and a hydroxylamine, and in combination are able to be highly effective at preventing the formation of unwanted formation of polymer in a composition that includes monomer. The observed antipolymerant effect is shown to be unexpectedly beneficial, meaning that the degree of inhibition of polymer formation is greater when the naphthoquinone and hydroxylamine are used in combination as compared to the degree of polymerization inhibition when the naphthoquinone and hydroxylamine are used separately, operating under the same total antipolymerant concentrations.

[23] An “unexpected beneficial antipolymerant combination effect” can be observed when the combination of two antipolymerants (a first antipolymerant and a second antipolymerant) provides a level of polymerization inhibition at a total antipolymerant concentration that is greater than the level of polymerization inhibition when either the first or the second antipolymerant is used alone at the amount of total antipolymerant concentration based on the combination. As an example, a first antipolymerant used at a first concentration (e.g., 200 ppm) and which provides an antipolymerant activity with a level of polymerization (e.g., polystyrene formation) at “80”, and a second antipolymerant is also used at a first concentration (e.g., 200 ppm) and which provides an antipolymerant activity with a level of polymerization (e.g., polystyrene formation) at “90”, an “expected” level of antipolymerant activity when the first and second antipolymerants are used in combination at a total concentration of 200 ppm (e.g., 100 ppm each first and second antipolymerants) would be “85” (the average of the levels of polymerization using the first and second antipolymerants). Therefore, if the combination of first and second antipolymerants at the total concentration is less than “85” (the average being expected), or especially less than “80” (the first antipolymerant), then the combination of the antipolymerants is considered to provide an “unexpected” antipolymerant activity, as each antipolymerant is not antagonistic to the other, and the combination performs better than the average of both, or better than either first or second antipolymerant at comparable concentrations. This unexpected level of inhibition of polymerization when first and second antipolymerants are used in combination can optionally be referred to as “synergistic”, such as “synergistic antipolymerant activity”. A test for unexpected antipolymerant activity can also be performed even if the first and second antipolymerants are used at different concentrations in combination. Here, an “expected” antipolymerant activity again can be calculated based on an average of the first and second antipolymerants used individually at the total antipolymerant concentration. The beneficial antipolymerant activity of the naphthoquinone and hydroxylamine combination can be caused by the ability of the combination to very effectively inhibit and retard formation of polymer in a monomer composition, wherein such activity can be observed over a period of time, such as exemplified herein.

[24] The ability of the inventive combination of the naphthoquinone and hydroxylamine can be expressed in terms of a percent (%) reduction as compared to either the naphthoquinone and hydroxylamine used at the total concentration, or the average of the naphthoquinone and hydroxylamine used individually at the total concentration. For example, using testing methods, such as described herein, formation of polymer (measured as % w/w) in a monomer composition containing either the naphthoquinone and hydroxylamine at a total concentration can be determined under conditions promoting polymer formation, and optionally over a period of time. The amount of polymer formation in a combination composition of naphthoquinone and hydroxylamine (each used at a half of the total concentration) is then determined, and compared to either the average of naphthoquinone and hydroxylamine, or the naphthoquinone or hydroxylamine, used individually, at the total concentration. In embodiments, the combination shows a reduction in polymerization of 10% or greater, 20% or greater, 30% or greater, 40% or greater, 50% or greater, 60% or greater, 70% or greater, or 80% or greater, such as up to about 90 % or greater, or a reduction in an % amount in the range of any of these numbers, as compared to the average, or as compared to either the of naphthoquinone and hydroxylamine used individually at the total concentration.

[25] The unexpected (e.g., synergistic) antipolymerant effect can be observed, for example, when the combination of the naphthoquinone and hydroxylamine are introduced into a hydrocarbon composition that includes a polymerizable monomer, or a compound capable for forming a polymerizable monomer, such as a hydrocarbon composition that includes styrene. The combination can be introduced into a hydrocarbon composition that is undergoing refining, or can be introduced into a refined hydrocarbon composition, such as one that is being transported or stored.

[26] “Antipolymerants” as used herein are compounds that can reduce the formation of polymers from one or more radically polymerizable compounds. Antipolymerants may be more specifically categorized as polymerization inhibitors and polymerization retarders. A polymerization inhibitor, in the presence of polymerizable monomers, inhibits the formation of a polymer from those monomers during the induction time. After the induction time has lapsed, the polymer's formation occurs at substantially the same rate that it would form at in the absence of the polymerization inhibitor. A polymerization retarder does not exhibit an induction time, but instead once added to a polymerizable monomer composition reduces the rate at which the formation of the polymer occurs relative to the rate at which it would have formed in the absence of the composition of matter. Polymerization inhibitors, as opposed to polymerization retarders, are generally consumed rapidly. Polymerization retarders, while they slow down the rate of polymerization reactions, are not as effective as polymerization inhibitors.

Polymerization retarders, however, are usually not consumed as quickly as polymerization inhibitors. The inventive combination of the naphthoquinone and hydroxylamine components can provide a beneficial antipolymerant effect, thereby reducing the formation of polymers in the presence of a monomer-containing composition, by inhibiting and retarding polymer formation. This beneficial activity can be observed over a period of time, such as exemplified herein.

[27] Aspects of the disclosure provide a composition for inhibiting monomer polymerization that include a naphthoquinone and hydroxylamine. A composition that includes these components (and any one or more optional component) can be in a desired form, such as in a liquid form, a dry form, or as a suspension or dispersion. The naphthoquinone and hydroxylamine can be in desired physical states in the composition, such as in a dissolved state, in a partially dissolved state, in a suspended state, or in a dry mixture. Also, the naphthoquinone and hydroxylamine can be in desired forms in the composition, such as optionally in particulate forms. If one or more of the components is in a particulate form, the particles can optionally be described in terms of particle size (e.g., particles of a size range) and/or shape. The form of the composition and the state of the components therein can be chosen by selection of naphthoquinone and hydroxylamine, with an understanding of the physical property of each compound. The form of the composition and the state of the components therein can also be affected by the inclusion of one or more optional components, such as a solvent, or solvent mixture, or other excipient compounds like surfactants, dispersants, etc. The form of the composition and the state of the components therein can also be affected by temperature, and composition properties may optionally be described in circumstances at a particular temperature (e.g., at a storage temperature such as 5°C or below, at room temperature (25°C), or at a temperature used for monomer synthesis and/or processing (e.g., about 100°C or greater, about 150°C, about 175°C, etc.).

[28] A composition including the naphthoquinone and hydroxylamine can optionally include other components in the composition (e.g., described in terms of a composition “comprising” the naphthoquinone and hydroxylamine). For example, such compositions can include other components such as a solvent, surfactants, dispersants, etc. If an optional component is present in the composition, it may be described in terms of a weight amount relative to one or more of the naphthoquinone and hydroxylamine compounds in the composition. The optional component may be present in a weight amount greater than, or an amount less than, any one of the naphthoquinone and hydroxylamine, or the total amount of naphthoquinone and hydroxylamine.

[29] As used herein, the term "optional" or "optionally" means that the subsequently described object (e.g., compound), event (e.g., processing step), amount, or circumstance may, but need not occur, and that the description includes instances where the object, event, amount, or circumstance occurs and instances in which it does not.

[30] Compositions of the disclosure can include those recited compounds and optionally can include other components in the composition but in very small amounts (e.g., described in terms of a composition “consisting essentially of’ the recited components). For example, such compositions can include one or more other components but not in an amount that is greater than about 1% (wt), about 0.5% (wt), or about 0.1% (wt), of the total composition. A composition that consists essentially of the naphthoquinone, hydroxylamine, and a solvent can optionally include one or more other components, but in an amount less than about 1% (wt) of the total composition. In a composition “consisting of’ the recited components there is no other measurable amount of component other than the recited component. [31] Likewise, the chemistries of compounds of the disclosure, including the naphthoquinone and hydroxylamine can, in some embodiments, be described in terms of the compound “consisting of’ certain atoms or certain chemical groups. For example, in embodiments of the disclosure a compound, such as the hydroxylamine component, can consist of carbon (C), hydrogen (H), oxygen (O), and nitrogen (N), and will not have any other types of atoms aside from C, H, O, and N, in the compound. As another example, a compound consisting of a hydrocarbyl group, a hydroxyl group, and an amine group will not have any other chemical groups aside from these.

[32] As used herein, the terms "substantially" and “consisting essentially of’ modifying, for example, the type or quantity of an ingredient in a composition, a property, a measurable quantity, a method, a position, a value, or a range, employed in describing the embodiments of the disclosure, refers to a variation that does not affect the overall recited composition, property, quantity, method, position, value, or range thereof in a manner that negates an intended composition, property, quantity, method, position, value, or range. Examples of intended properties include, solely by way of nonlimiting examples thereof, dispersibility, stability, rate, solubility, and the like; intended values include weight of a component added, concentration of components added, and the like. The effect on methods that are modified include the effects caused by variations in type or amount of materials used in a process, variability in machine settings, the effects of ambient conditions on a process, and the like wherein the manner or degree of the effect does not negate one or more intended properties or results; and like proximate considerations. Where modified by the term "substantially" or “consisting essentially of,” the claims appended hereto include equivalents to these types and amounts of materials.

[33] As used herein, the term "about" modifying, for example, the quantity of an ingredient in a composition, concentration, volume, process temperature, process time, yield, flow rate, pressure, and like values, and ranges thereof, employed in describing the embodiments of the disclosure, refers to variation in the numerical quantity that can occur, for example, through typical measuring and handling procedures used for making compounds, compositions, concentrates or use formulations; through inadvertent error in these procedures; through differences in the manufacture, source, or purity of starting materials or ingredients used to carry out the methods, and like proximate considerations. The term "about" also encompasses amounts that differ due to aging of a formulation with a particular initial concentration or mixture, and amounts that differ due to mixing or processing a formulation with a particular initial concentration or mixture. Where modified by the term "about" the claims appended hereto include equivalents to these quantities. Further, where “about” is employed to describe any range of values, for example “about 1 to 5” the recitation means “1 to 5” and “about 1 to about 5” and “1 to about 5” and “about 1 to 5” unless specifically limited by context.

[34] Some R groups in formulas of the disclosure can include hydrocarbon-containing groups such as alkyl groups, including linear, branched, and cyclic alkyl groups, aryl groups, alkyl aryl groups (e.g., ethyl-benzyl), aryl alkyl groups (e.g., propyl-phenyl), and combinations thereof. Cyclic alkyl or aryl groups can have fused structures such as decahydronaphthalene, naphthalene, tetradecahydro-anthracene, anthracene, etc. In some embodiments, hydrocarbon groups of formulas of the disclosure can be defined by the number of carbon atoms in the group, such as 1 -12 carbons, 1-10 carbons, 1-8 carbons, 1-6 carbons, 1-5 carbons, 1-4 carbons, or 1-3 carbons.

[35] Compositions and methods of the disclosure include or use a naphthoquinone. In embodiments, compositions and method of the disclosure use one or more naphthoquinone(s) having chemical based on 1 ,4-naphthoquinone and 1,2-naphthoquinone architectures according to Formula III and IV, respectively.

[36]

[37] In embodiments, in Formulas III and IV, i -R 6 are -H providing the compounds 1 ,4-naphthoquinone and 1,2-naphthoquinone.

[38] Alternatively, two adjacent groups of R 1 , R 2 , R 3 , or R 4 (i.e., R 1 and R 2 ; R 2 and R 3 ; or R 3 and R 4 ) form one or more ring structures. This can provide, for example, anthracene, fused ring structures derived from naphthoquinone.

[39] Compositions and methods of the disclosure include or use a naphthoquinone. In embodiments, compositions and method of the disclosure use one or more naphthoquinone(s) having chemical based on 1 ,4-naphthoquinone and 1 ,2-naphthoquinone architectures according to Formula III and IV, respectively.

[40] In embodiments, in Formulas III and IV, R'-R 6 are -H and provide the compounds 1,4-naphthoquinone and 1 ,2-naphthoquinone, respectively.

[41] In embodiments, one or more of R'-R 6 are a chemical group other than -H, such a chemical group selected from the group consisting of alkyl, aryl, alkyl aryl and aryl alkyl groups of 1 to 24 carbon atoms.

[42] In embodiments, the naphthoquinone is an aminated naphthoquinone. For example, in Formula III or IV, the naphthoquinone can include one or more amine groups, wherein one or both of-R 5 and/or -R 6 is or are -NR 5 R 6 , wherein R 5 and R 6 are selected from the group consisting of hydrogen, alkyl, aryl, alkyl aryl and aryl alkyl groups of 1 to 24 carbon atoms. Exemplary aminated naphthoquinone antipolymerants can have the general chemistries of 2-amino, 1,4-naphthoquinone, 2, 3 -diamino, 1,4-naphthoquinone, 2- amino, 1,3 -naphthoquinone, 4-amino,l,3-naphthoquinone, 2,4-diamino,l ,3- naphthoquinone, 3-amino,l,2-naphthoquinone, 4-amino,l,2-naphthoquinone, and 3,4- diamino, 1 ,3 -naphthoquinone.

[43] Exemplary aminated naphthoquinone are described in Applicant’s U.S. Patent No. 11,312,792 (Masere, April 26, 2022), the disclosure of which is incorporated herein by reference.

[44] Compositions and methods of the disclosure include or use a hydroxylamine along with the naphthoquinone, which provide an unexpected (e.g., synergistic) antipolymerant effect with present together in a monomer-containing composition.

[45] The hydroxylamine compound has one or more amine groups that are bonded to hydroxyl group. In some embodiments the hydroxylamine compound is a “primary hydroxylamine” referring to a compound having a nitrogen atom bonded to: a hydroxy group (-OH), a hydrogen (-H), and a chemical group that is not a hydroxyl group or a hydrogen, such as a hydrocarbon-containing group. In some embodiments the hydroxylamine compound is a “secondary hydroxylamine” referring to a compound having a nitrogen atom bonded to: a hydroxy group (-OH), and two chemical groups that are not a hydroxyl group or a hydrogen, such as a hydrocarbon-containing group, or alternatively the secondary hydroxylamine is a cyclic compound wherein the nitrogen is a heteroatom in a ring structure, and is also bonded to a hydroxyl group.

[46] The hydroxylamine can also be described in terms of atomic composition, for example, hydroxylamine has one or more primary hydroxylamine group, and/or one or more secondary hydroxylamine groups, and at least 1, at least 2, at least 3, or at least 4 carbon atoms, and up to 60, up to 48, up to 36, up to 24, up to 18, up to 15, or up to 12 carbon atoms. In some preferred embodiments, the hydroxylamine has a number of carbons in the range of 3 - 24, in the range of 3 - 18, or in the range of 3 - 15.

[47] The hydroxylamine can include one or more oxygen atoms, wherein at least one of the oxygen atoms is in the form of a hydroxyl group bonded to the nitrogen on the hydroxylamine group. In embodiments, the hydroxylamine has a number of oxygen atoms in the range of 1 -8, in the range of 1-6, in the range of 1-4, or in the range of 1-3. In embodiments wherein the hydroxylamine includes two of more oxygen atoms, most, or all, of the oxygen atoms can be in the form of hydroxyl groups in the hydroxylamine.

[48] The hydroxylamine can consist of certain atoms to the exclusion of others. In some embodiments the hydroxylamine consists of nitrogen, carbon, oxygen, and hydrogen atoms.

[49] In embodiments, the hydroxylamine is of Formula I: HO-NR’R 2 , wherein at least one or both of R 1 and R 2 is or are a carbon-containing group having 1-12 carbon atoms, optionally substituted with one or more hydroxyl groups, wherein R 1 or R 2 is -H if not the carbon-containing group. R 1 of Formula I (HO-NR’R 2 ) can be selected from (i) Cl -Cl 2 alkyl groups, (ii) C1-C8 alkyl groups, and (iii) C1-C6 alkyl groups, wherein (i)-(iii) have linear, branched, or cyclic architectures, or combinations thereof. R 2 of Formula I (HO- NR’R 2 ) can be selected from (iv) -H and Cl -Cl 2 alkyl groups, (v) -H and C1-C8 alkyl groups, or (vi) -H and C1-C6 alkyl groups, wherein the alkyl groups of (iv)-(vi) have linear, branched, or cyclic architectures, or combinations thereof, and wherein any one or more alkyl groups of (i)-(vi) are optionally substituted with one or more hydroxyl groups.

[50] In embodiments, one or both of R 1 or/and R 2 in Formula I (HO-NR'R 2 ) can be selected from linear, branched, and cyclic alkyl, aryl, alkyl-aryl, and aryl-alkyl Cl -Cl 2 groups. Exemplary R 1 or/and R 2 group(s) include those such as: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, cyclopentyl, isopentyl, neopentyl, hexyl, cyclohexyl, 1-, 2-, and 3 -methylbutyl, 1,1-, 1,2-, or 2,2-dimethylpropyl, 1 -ethylpropyl, 1-, 2-, 3-, or 4-methylpentyl, 1,1-, 1,2-, 1,3-, 2,2-, 2,3-, or 3, 3 -dimethylbutyl, 1- or

2-ethylbutyl, 1 -ethyl- 1 -methylpropyl, and 1,1,2- or 1 ,2,2-trimethylpropyl, methylcyclopentyl; heptyl, 2-methylhexyl, 3 -methylhexyl, 4-methylhexyl, 5-methylhexyl,

3-ethylpentyl, 2,2,3-trimethylbutyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, 2,4- dimethylpentyl, 3,3-dimethylpentyl, 3,4-dimethylpentyl, 4,4-dimethylpentyl, cycloheptyl, 1 -methylcyclohexyl, and 2-methylcyclohexyl; octyl, 2-methylheptyl 3-methylheptyl, 4- methylheptyl, 2-ethylhexyl, 3-ethylhexyl, 4-ethylhexyl, 5-ethylhexyl, 2,2-dimethylhexyl, 2,3-dimethylhexyl, 2,4-dimethylhexyl, 2,5-dimethylhexyl, 3, 3 -dimethylhexyl, 3,4- dimethylhexyl, 3-ethyl-2-methylpentyl, 3-ethyl-3-methylpentyl, 2,2,3-trimethylpentyl, 2,2,4-trimethylpentyl, 2, 3, 3 -trimethylpentyl, 2,3,4-trimethylpentyl, and 2, 2,3,3- tetramethylbutyl.

[51] In embodiments, one or both of R 1 or/and R 2 in Formula I (HO-NR'R 2 ) can be independently selected from hydroxylated linear, branched, and cyclic alkyl, aryl, alkylaryl, and aryl-alkyl Cl -Cl 2 groups. In some embodiments, one or both of R 1 and R 2 are of the formula: -(CR 10 2) 9 (CHOH)(CH2)zR n , where R 10 is independently selected from -H and alkyl, wherein q and z are independently (-) (a covalent bond), or an integer in the range of 1-12, and R 11 is selected from the group consisting of Cl -Cl 2 linear, branched, or cyclic alkyl, aryl, alkyl-ary 1, and aryl-alkyl, optionally substituted with one or more hydroxyl groups. In embodiments, q and z are independently (-), 1, or 2. In some embodiments, R 10 is -H; q is 1; z is (-); and R 11 is selected from C1-C12 linear, branched, or cyclic alkyl, aryl, alkyl-aryl, and aryl-alkyl groups. Exemplary alkyl, alkyl-aryl, and aryl-alkyl groups are described herein. Exemplary species of the formula: - (CR 10 2) 9 (CHOH (CH2)_-R 11 , include the following groups:

[52] In embodiments, one or both of R 1 or/and R 2 in Formula I (HO-NR’R 2 ) that is the carbon-containing group having 1-12 carbon atoms comprises an aryl group. For example, one or both of R 1 and R 2 are of Formula V: wherein R 6 is independently selected from the group consisting of -H, -OH, and alkyl, wherein v is an integer in the range of 1-6, R 7 is independently selected from the group consisting of -H, -OH, and alkyl, wherein q is an integer in the range of 1-5.

[53] In embodiments -(CHR 6 ) V - includes the formula -(CR 10 2)< 7 (CHOH)(CH2) ; -- , which is exemplified by the following groups:

[54] In some embodiments the hydroxylamine is selected from the group consisting of benzylhydroxylamine, N-phenethyl-hydroxylamine, N-(3-phenyl-propyl)-hydroxylamine, N-(4-phenyl-butyl)-hydroxylamine, N-(5-phenyl-pentyl)-hydroxylamine, N-(6-hexyl- propyl)-hydroxylamine, N-(3-phenyl-2-methyl-propyl)-hydroxylamine, and N-(4-phenyl- 3-methyl-butyl)-hydroxylamine;

[55] In some embodiments the hydroxylamine is selected from the group consisting of dibenzylhydroxylamine, N,N-bis(phenethyl) hydroxylamine, N,N-bis(3- phenylpropyl)hydroxylamine, N,N-bis(4-phenyl-butyl)-hydroxylamine, N,N-bis(5-phenyl- pentyl)-hydroxylamine, N,N-bis(6-hexyl-propyl)-hydroxylamine, N,N-bis(3-phenyl-2- methyl-propyl)-hydroxylamine, and N,N-bis(4-phenyl-3-methyl-butyl)-hydroxylamine

[56] In some embodiments the hydroxylamine is selected from the group consisting of N-(2 -phenyl- 1 -hydroxyl-ethyl)hydroxylamine, N-(3-phenyl-2-hydroxyl-propyl)- hydroxylamine, N-(4-phenyl-2-hydroxyl-butyl)-hydroxylamine, N-(5-phenyl-2-hydroxyl- pentyl)-hydroxylamine, N-(6-hexyl2-hydroxyl-propyl)-hydroxylamine,

[57] In some embodiments the hydroxylamine is selected from the group consisting of N,N-bis(2-phenyl-l -hydroxy l-ethyl)hydroxylamine, N,N-bis(3-phenyl-2-hydroxyl- propyl)-hydroxylamine, N,N-bis(4-phenyl-2-hydroxyl-butyl)-hydroxylamine, N,N-bis(5- phenyl-2-hydroxyl-pentyl)-hydroxylamine, and N,N-bis(6-hexyl2-hydroxyl— propylhydroxy lamine.

[58] In some embodiments, the compound of Formula I is selected from the group consisting of N,N-dimethylhydroxylamine, N-methyl-N-ethylhydroxylamine, N-methyl- N-propylhydrox lamine, N-methyl-N-isopropylhydroxylamine, N-methyl-N- propylhydroxylamine, N-methyl-N-butylhydroxylamine, N-methyl-N- isobutylhydroxylamine, N-methyl-N-t-butylhydroxylamine, N-,N-diethylhydroxylamine, N-ethyl-N-propylhydroxylamine, N-ethyl-N-isopropylhydroxylamine, N-ethyl-N- propylhydroxylamine, N-ethyl-N-butylhydroxylamine, N-ethyl-N-isobutylhydroxylamine, N-ethyl-N-t-butylhydroxylamine, N-,N-dipropylhydroxylamine, N-,N- diisopropylhydroxylamine, N-propyl-N-butylhydroxylamine, N-isopropyl-N- butylhydroxylamine, N-propyl-N-isobutylhydroxylamine, N-propyl-N-t- butylhydroxylamine, N-ispropyl-N-isobutylhydroxylamine, and N-isopropyl-N-t- butylhydroxylamine.

[59] In some embodiments, the compound of Formula I is selected from the group consisting of N-methylhydroxylamine, N-ethylhydroxylamine, N-propylhydroxylamine, N-isopropylhydroxylamine, N-butylhydroxylamine, N-isobutylhydroxylamine, N-t- butylhydroxylamine, N-sec-butylhydroxylamine, N-pentylhydroxylamine, N-cyclo- pentylhydroxylamine, N-isopentylhydroxylamine, N-neopentylhydroxylamine, N- hexylhydroxylamine, N-cyclohexylhydroxylamine, N-1-, 2-, and 3-methylbutylhydroxyl- amine, N-1,1-, 1,2-, or 2,2-dimethylpropylhydroxylamine, N-l-ethyl-propylhydroxyl- amine, 1-, 2-, 3-, or 4-methylpentylhydroxylamine, N-1 ,1-, 1,2-, 1,3-, 2,2-, 2,3-, or 3,3- dimethylbutylhydroxylamine, N-l- or 2-ethylbutylhydroxylamine, N- 1 -ethyl- 1-methyl- propylhydroxylamine, and N-l, 1,2- or 1,2,2-trimethylpropylhydroxylamine, and N- methylcyclopentylhydroxylamine.

[60] In some embodiments, the compound of Formula I is selected from the group consisting of N-hydroxymethylhydroxylamine, N-1-, or 2-hydroxyethylhydroxylamine, N-

1-, 2- or 3-hydroxypropylhydroxylamine, N-1-, or 2-hydroxypropylhydroxylamine, N-1-,

2-, 3-, or 4-hydroxybutylhydroxylamine, N-1-, 2- or 3 -hydroxy isobutylhydroxylamine, N-

1-, 2- or 3-hydroxysecbutylhydroxylamine, N-2-hydroxy-t-butylhydroxylamine, and N-1-,

2-, 3-, 4, or 5-N-hydroxypentyIhydroxylamine;

[61] In some embodiments, the compound of Formula I is selected from the group consisting ofN,N-bis(hydroxymethyl)hydroxylamine, N,N-bis(l-, or 2-hydroxyethyl) hydroxylamine, N,N-bis(l-, 2- or 3-hydroxypropyl)hydroxylamine, N,N-bis(l-, or 2- hydroxypropyl) hydroxylamine, N,N-bis(l-, 2-, 3-, or 4-hydroxybutyl)hydroxylamine, N,N-bis(l-, 2- or 3-hydroxyisobutyl)hydroxylamine, N,N-bis(l-, 2- or 3-hydroxysec- butyl)hydroxylamine, N,N-bis(2-hydroxy-t-butyl)hydroxylamine, and N,N-bis(l-, 2-, 3-, 4, or 5-N-hydroxypentyl)hydroxylamine.

[62] In some embodiments, the hydroxylamine is of Formula II: wherein X is -(CHR 5 ) W -, wherein R 5 is selected from the group consisting of -H, R 3 , and R 4 , R 3 is selected from -H and alkyl, and R 4 is selected from -H and -OH, y is 0 or an integer in the range of 1 -3, z is 0 or an integer in the range of 1 -3, and w is an integer in the range 1-4.

[63] Exemplary species of Formula II include N-hydroxypyrrolidine, N- hydroxypiperidine, azepanol, and azocanol.

[64] Other exemplary species of Formula II include alkylated, such as having C1-C6 alkylation, N-hydroxypyrrolidine, N-hydroxypiperidine, azepanol, and azocanol, hydroxylated N-hydroxypyrrolidine, N-hydroxypiperidine, azepanol, and azocanol, and compounds having both alkylation and hydroxylation. [65] Hydroxylamines of the disclosure are generally in liquid or solid form at room temperature (25°C). Some hydroxylamines with a number of carbon atoms or alkyl chain lengths of about 12 or may be in solid form at room temperature. In some embodiments, hydroxylamines compounds of the disclosure have melting points in the range of about - 50°C to about 200°C, in the range of about -30°C to about 150°C, or in the range of about - 10°C to about 125°C. In some embodiments, hydroxylamines compounds of the disclosure have a boiling point of about 100°C or greater, about 110°C or greater, about 120°C or greater, about 130°C or greater, about 140°C or greater, about 150°C or greater, about 160°C or greater, about 170°C or greater, about 175°C or greater, about 180°C or greater, about 185°C or greater, about 190°C or greater, about 195°C or greater, such as in the range of about 100°C to about 300°C, or about 150°C to about 250°C.

[66] Amounts of the naphthoquinone and hydroxylamine in a composition can be described in various ways, such as by a weight percentage (% wt.) of each component in the composition, or by molar amounts of the compounds. These compounds can also be described in terms of weight ratios, or in terms of relative amounts to one another, in a composition.

[67] In some embodiments, in a composition the naphthoquinone and hydroxylamine are used at a desired molar ratio, such as a ratio in the range of 10: 1 to 1 : 10, in the range of 5: 1 to 1 :5, in the range of 2.5: 1 to 1 :2.5, in the range of 2:1 to 1 :2, in the range of 1.5: 1 to 1 :1.5, in the range of 1.25: 1 to 1 :1.25, or in the range of 1.1 : 1 to 1 : 1.1. In some embodiments the naphthoquinone and hydroxylamine are used at approximately the same molar amounts.

[68] The naphthoquinone and hydroxylamine can be present in a composition with a solvent, or a combination of solvents. A solvent or solvent combination can be chosen so that at least one of the naphthoquinone and hydroxylamine is soluble in the solvent or solvent combination. If the hydroxylamine is a liquid at ambient conditions, the solvent can be chosen so that it is miscible with the hydroxylamine.

[69] In embodiments, the hydroxylamine may also function as a solvent, and can be used to solvate the naphthoquinone. In these embodiments, the hydroxylamine may be used at a desired amount in relation to the naphthoquinone, even in an amount that is greater than the naphthoquinone.

[70] The composition can also include one or more solvents. Useful solvents include any solvent in which a combination naphthoquinone and hydroxylamine are soluble or can be stably suspended. In some embodiments, a solvent or solvent combination can be selected from water-soluble or water -miscible solvents such glycol-based solvents and hydrophobic solvents such as aromatic solvents, paraffinic solvents, or mixtures of both.

[71] Exemplary glycol solvents include, but are not limited, Ci-Cs glycols such as ethylene glycol, propylene glycol, diethylene glycol, and triethylene glycol, ethers of such glycols such as diethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, liquid polyethylene glycol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and a low molecular weight polypropylene glycol and the like and combinations thereof.

Commercial solvents such as Butyl Carbitol and Butyl CELLOSOLVE™, which contains primarily Butyl CARBITOL™, which consists primarily of ethylene glycol monobutyl ether may be used and are available from DOW.

[72] Other exemplary hydrophobic solvents include heavy aromatic naphtha, toluene, ethylbenzene, and isomeric hexanes, and mixtures of two or more thereof.

[73] The amount of one or more solvents in a composition that includes the naphthoquinone and hydroxylamine is not particularly limited. In some embodiments, the amount of one or more solvents in the composition can be about 10 wt% to 50 wt%, for example, about 20 wt% to 50 wt%, or about 25 wt% to 50 wt%, or about 10 wt% to 40 wt%, or about 10 wt% to 30 wt%, or about 20 wt% to 40 wt%, or about 25 wt% to 40 wt% of the total composition.

[74] In some embodiments the composition includes the naphthoquinone in an amount in the range of 5 to 45% (wt); the hydroxylamine in an amount in the range of 5 to 45% (wt); and a solvent, or solvent combination, in an amount in the range of 10 to 90% (wt). In some embodiments the composition includes the naphthoquinone in an amount in the range of 15 to 35% (wt); the hydroxylamine in an amount in the range of 15 to 35% (wt); and a solvent, or solvent combination, in an amount in the range of 30 to 70% (wt). In some embodiments the composition includes the naphthoquinone in an amount in the range of 20 to 30% (wt); the hydroxylamine in an amount in the range of 20 to 30% (wt); and a solvent, or solvent combination, in an amount in the range of 30 to 70% (wt). Compositions including naphthoquinone and hydroxylamine at concentrations that are higher than “working” concentrations of naphthoquinone or the hydroxylamine (typically measured in ppm, can be referred to as “concentrates” or “stock” compositions.

[75] Compositions of the disclosure can be made using any desired method. In some modes of making, a solution of the naphthoquinone or the hydroxylamine with solvent can first be obtained by a user, such as a commercial preparation, and then either the naphthoquinone or the hydroxylamine is added subsequently, such as in a point of use procedure.

[76] A composition that includes a mixture of the naphthoquinone and hydroxylamine, optionally with solvent, can be provided as a “shelf-stable” composition, and then subsequently used in a process to inhibit polymerization of monomers. For example, methods of the disclosure can include a step of preparing a composition of naphthoquinone or the hydroxylamine, and then storing the composition for a period of time, and then using the composition in a process to inhibit polymerization of monomers.

[77] Methods of abating the polymerization of monomers in a monomer- containing composition can be carried out by adding the naphthoquinone and the hydroxylamine to a composition that includes a polymerizable monomer. The naphthoquinone and the hydroxylamine inhibit the polymerization of the polymerizable monomer, and their beneficial use in combination provide a degree of polymerization inhibition that is greater than that additive inhibitor of the inhibitors used individually at corresponding concentration. In other words, the combination of the naphthoquinone and the hydroxylamine provide an unexpected (e.g., synergistic) effect to inhibit monomer polymerization, which in turn provides benefits for various processes where inhibiting monomer polymerization is desired.

[78] As noted herein, the naphthoquinone and hydroxylamine can provide an unexpected (e.g., synergistic) effect when used together in a monomer-containing composition, which can in turn eliminate the need for one or more other types of polymerization inhibitors to be used concomitantly with the naphthoquinone and hydroxylamine. Other types of polymerization inhibitors that may be excluded from use at the same time as the naphthoquinone and hydroxylamine, or may be used at very small concentrations, can include nitroxide-, amine oxide-, nitro-, nitroso-, and nitronecontaining compounds.

[79] For example, if even present, any nitroxide-, amine oxide-, nitro-, nitroso-, and nitrone-containing compound can optionally be present in an amount of less than 50 ppm, less than 25 ppm, less than 10 ppm, less than 5 ppm, less than 2.5 ppm, less than 2 ppm, less than 1.5 ppm, less than 1 ppm, less than 0.75 ppm, or less than 0.5 ppm, in a working composition with monomer.

[80] Exemplary nitroxide-containing inhibitor include di-tert-butyl nitroxyl, 2, 2,6,6- tetramethylpiperidinyl-l-oxyl (TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-l- oxyl(HTMPO), 4-oxo-2,2,6,6-tetramethylpiperidinyl-l-oxyl (OTEMPO), which may be excluded from additive compositions of the disclosure, or not be added to a monomer composition concomitantly with the naphthoquinone and hydroxylamine. These types of compounds may be excluded from use at the same time as the naphthoquinone and hydroxylamine, or may be used at very small concentrations, as noted herein.

[81] Exemplary hydroxylamine-containing polymerization inhibitors include, but are not limited to: 1 -hydroxy-2,2, 6, 6- tetramethylpiperidine (TEMPOH), 1,4-dihydroxy- 2,2,6,6-tetramethylpiperidine (HTMPOH), and 1 -hydroxy-4-oxo-2, 2,6,6- tetramethylpiperidine (OTEMPOH), N,N-diethylhydroxylamine, and N- isopropylhydroxylamine. These types of compounds may be excluded from use at the same time as the naphthoquinone and hydroxylamine, or may be used at very small concentrations, as noted herein.

[82] Exemplary nitro-containing polymerization inhibitors include, but are not limited to: nitrobenzene, nitrophenol, dinitrophenol, 2,4-dinitro-6-s-butylphenol, 2,4-dinitro-o- cresol, and diphenyl picrylhydrazyl. These types of compounds may be excluded from use at the same time as the naphthoquinone and hydroxylamine, or may be used at very small concentrations, as noted herein.

[83] Exemplary nitroso-containing polymerization inhibitors include, but are not limited to: nitrosobenzene, nitrosophenol, dinitrosophenol, dinitrosotoluene, nitrosophenyl-hydroxylamine. These types of compounds may be excluded from use at the same time as the naphthoquinone and hydroxylamine, or may be used at very small concentrations, as noted herein.

[84] Although it is preferred that naphthoquinone and hydroxylamine is used to provide an antipolymerant effect without the use of a nitroxide-, amine oxide-, nitro-, nitroso-, and nitrone-containing compound, or optionally with such a compound in a very small amount, the methods of the disclosure do not preclude using a monomer-containing composition that has been previously treated with a nitroxide-, amine oxide-, nitro-, nitroso-, or nitrone-containing compound, nor does it preclude a method wherein such a compound is added at a time after the naphthoquinone and hydroxylamine treatment. For example, the disclosure contemplates hydrocarbon and monomer-containing compositions previously treated with an, e.g., nitroxide compound, and then after a period of time wherein the nitroxide compound loses its effectiveness, the naphthoquinone and hydroxylamine are then added to the hydrocarbon and monomer-containing composition. Optionally, the disclosure also contemplates hydrocarbon and monomer-containing compositions that are treated with the naphthoquinone and hydroxylamine, and then subsequently treated with a compound different than the naphthoquinone and hydroxylamine.

[85] The polymerizable monomer that is subjected to polymerization inhibition can include a vinyl or ethylenically unsaturated group. For example, the naphthoquinone and hydroxylamine can be added to a composition that includes one or more of the following polymerizable monomers: acrylic acid, acrylonitrile, alkylated styrene, butadiene, chloroprene, divinylbenzene, ethyl acrylate, ethyl methacrylate, isoprene, methacrylic acid, methyl methacrylate, methyl acrylate, a-methylstyrene, methacrylonitrile, styrene, styrene sulfonic acid, vinyltoluene, and vinylpyridine.

[86] The polymerizable monomer can be present in a crude mixture of compounds, a semi-refined mixture of compounds, or a fully-refined mixture of compounds. For example, the naphthoquinone and hydroxylamine can be added to a process stream that includes the polymerizable monomer. In methods, the components can be added before, during, or after, (or combinations thereof) a processing step, such as distillation, wherein compounds in the composition are separated from one another. The components can inhibit polymerization of monomer at any one or more stages in a processing system, and minimize fouling of equipment.

[87] Alternatively, the components of the naphthoquinone and hydroxylamine can be added to a process stream that includes a compound capable of the polymerizable monomer. For example, in compositions including a compound that is capable of forming a polymerizable monomer as an unwanted by-product, the presence of the naphthoquinone and hydroxylamine can inhibit polymerization of the monomer if it does form as a byproduct, and can therefore minimize fouling of equipment.

[88] In some modes of practice, the naphthoquinone and hydroxylamine are introduced into a monomer-containing composition to provide a desired amount of each reagent in the composition. The naphthoquinone and hydroxylamine can be introduced simultaneously, such as delivered from a composition where the components are in mixture, or can be delivered individually or partially combined either sequentially, or in an overlapping manner.

[89] If the naphthoquinone and hydroxylamine are introduced into a monomer- containing composition sequentially, preferably the additions are performed to allow the naphthoquinone and hydroxylamine combination to provide an unexpected (e.g., synergistic) antipolym erant effect to the composition. [90] The resulting introduction of the components into the monomer-containing composition can provide the naphthoquinone and hydroxylamine at desired concentrations. For example, at a polymerizable monomer concentration in the range of 50 to 200 ppm, the naphthoquinone is present in the composition in an amount in the range of 50 to 500 ppm, and the hydroxylamine is present in the composition in an amount in the range of 50 to 500 ppm. In some modes of practice, the naphthoquinone is present in the composition in an amount in the range of 75 to 400 ppm, and the hydroxylamine is present in the composition in an amount in the range of 75 to 400 ppm. In some modes of practice, the naphthoquinone is present in the composition in an amount in the range of

100 to 300 ppm, and the hydroxylamine is present in the composition in an amount in the range of 100 to 300 ppm. In some modes of practice, the naphthoquinone is present in the composition in an amount in the range of 150 to 250 ppm, and the hydroxylamine is present in the composition in an amount in the range of 150 to 250 ppm.

[91] The term “fouling” refers to the formation of polymers, prepolymers, oligomer and/or other materials which would become insoluble in and/or precipitate from a stream and deposit on equipment under the conditions of operation of the equipment. In turn, the naphthoquinone and hydroxylamine and compositions of the disclosure can be referred to as “antifouling” as they inhibit or reduce such formation.

[92] The components of the naphthoquinone and hydroxylamine can be used in conjunction with compositions containing polymerizable monomers and “process equipment” such as reactors, reactor beds, pipes, valves, distillation columns, trays, condensers, heat exchangers, compressors, fans, impellers, pumps, recirculators, intercoolers, sensors, and the like, that are associated with the process and which may be subject to fouling by monomer polymerization. This term also includes sets of these components where more than one of the components is part of a “system.”

[93] In one preferred method of use, a composition of the disclosure with naphthoquinone, hydroxylamine, and optional solvent is used with a process that involves a distillation tower that is used to separate and purify vinylic monomers. For example, in art-known processes ethylbenzene can be subjected to a catalytic dehydrogenation reaction which results in the formation of styrene. The reaction product containing styrene also contains other compounds such as aromatics like toluene and benzene, unreacted ethylbenzene, and other materials such as polymers. This mixture of compounds is generally fractionally distilled using one or more distillations towers. Typically, heat is used to help separate the components in the distillation tower. Following distillation, the fractionated components can be separated into pure product streams with higher purity.

[94] The naphthoquinone and hydroxylamine composition can be introduced into a stream leading from the reaction bed to the distillation tower, or can be directly added to the distillation tower. The inhibitor composition can be added prior to heating the monomer composition or while heating the monomer composition in the distillation tower. In some embodiments, the naphthoquinone and/or hydroxylamine have a boiling point that is greater than a desired compound (e.g., a monomer such as styrene) subject to distillation tower and during the distillation process the desired compound is separated from the hydroxylamine by virtue of temperature difference. In embodiments, the boiling point difference between the compound of interest and the naphthoquinone and/or hydroxylamine is about 10°C or greater, about 15°C or greater, about 20°C or greater, about 25°C or greater, about 30°C or greater, about 35°C or greater, about 40°C or greater, about 45°C or greater, or about 50°C or greater.

[95] Alternatively, or in addition to adding the inhibitor composition during the distillation process, the inhibitor composition can be added to a distillation effluent stream, such as a purified styrene stream.

[96] The components of the naphthoquinone and hydroxylamine can be used in conjunction with a “petroleum product” which refers to any hydrocarbon product obtained from a subterranean reservoir, any product derived therefrom, or any mixture thereof. Polymerizable monomers are found in or can be chemically derived from petroleum products. Nonlimiting examples of petroleum products include but are not limited to crude oil, reduced crude oil, crude distillate, heavy oil, or bitumen, hydrotreated oil, refined oil, byproducts of petroleum product processing such as pyrolysis, hydrotreating, or phase separation, or mixtures of two or more of these. A liquid petroleum product is a petroleum product that is substantially a liquid at 20 °C.

[97] The components of the naphthoquinone and hydroxylamine can be added to or can be present in a “petroleum process stream” which refers to any petroleum product disposed within petroleum process equipment in fluid contact with an interior surface thereof. The petroleum process stream can include, or can be capable of forming as a byproduct, one or more polymerizable monomer. The process stream may be substantially static, such as a petroleum product disposed in a settler (separator) or storage container for a selected period of contact, such as up to two years. The process stream may be substantially dynamic, such as a liquid petroleum product disposed within a pipe during transportation of the product from a first location to a second location. In some embodiments the process stream includes one or more additional components related to petroleum processing; such components are not particularly limited.

[98] “Petroleum process equipment” or “petroleum process apparatus” refers to a manmade item having an interior surface including a metal, further wherein one or more petroleum products are fluidly contacted with the metal for any period of time and at any temperature further as determined by context. Petroleum process equipment includes items for removing petroleum products from a subterranean reservoir, for transporting one or more petroleum products from a first location to a second location, or for separating, refining, treating, isolating, distilling, reacting, metering, heating, cooling, or containing one or more petroleum products.

[99] In embodiments, compositions including naphthoquinone and hydroxylamine are thermally stable and have antipolymerant activity in processing streams or other polymerizable monomer-containing compositions at temperatures of about 20°C to about 400°C, for example about 100°C to 400°C, or about 100°C to 350°C, or about 100°C to 300°C, or about 100°C to 250°C, or about 100°C to 200°C, or about 100°C to 150°C.

[100] In embodiments, compositions including naphthoquinone and hydroxylamine can be introduced into a composition with a polymerizable monomer, such as a liquid petroleum process stream in a batch-wise, a continuous, or a semi-continuous manner. In some embodiments, the naphthoquinone and hydroxylamine are introduced manually; and in other embodiments, their introduction is automated. In embodiments, the amount of the naphthoquinone and hydroxylamine introduced over a selected unit of time is varied with a variable composition of the associated process stream. Such variability in dosing may be conducted manually by periodic testing of the process equipment interior surfaces, following by ad justing the amount of the composition up or down based on test results; or automatically by monitoring of one or more conditions within the interior of the petroleum process equipment and signaling the need to apply more composition to the process stream.

[101] In some embodiments, the naphthoquinone and hydroxylamine are added to a petroleum product that is a crude oil, a reduced crude oil, a heavy oil, a bitumen, a coker charge, a hydrotreater influent, a hydrotreater effluent, a flashed crude, a light cycle oil, or a diesel or naphtha refinery stream. In embodiments, the compounds are added to petroleum process equipment conventionally associated with the collecting, processing, transportation, or storage of one or more of crude oil, reduced crude oil, crude distillate, heavy oil, bitumen, coker charge, flashed crude, light cycle oil, or a diesel or naphtha refinery stream, including pipes and associated infrastructure used to fluidly connect process equipment items together to facilitate processing of a process stream disposed therein.

[102] Equipment containing the polymerizable monomer-containing compositions that are treated with the naphthoquinone and hydroxylamine can result in reduction or elimination of fouling interior surface of the equipment. In embodiments, fouling is measured as a relative increase in retention of solids within the treated composition compared to the retention of solids in untreated composition over the same time period. In embodiments, fouling is measured as a relative decrease in the weight or volume of precipitate arising from a selected period of contact of a treated process stream in an associated process equipment item, relative to the same period of contact of the process equipment with the corresponding untreated process stream. Stated differently, a reduction in fouling is a relative decrease in the measured weight or volume of solids deposited on or precipitated from process equipment contacted with the treated process stream over a selected period of time, when compared to the weight or volume of solids deposited or precipitated from an untreated process stream over the same period of time.

[103] The naphthoquinone and hydroxylamine can also inhibit unwanted polymerization and fouling of the process equipment in a primary fractionation process, light ends fractionation, non-aromatic halogenated vinyl fractionation, process-gas compression, dilution steam system, caustic tower, quench water tower, butadiene extraction, propane dehydrogenation, diesel and petrol fuel stabilization, olefin metathesis, styrene purification, hydroxyhydrocarbon purification, or delays the polymerization of resins and compositions comprising ethylenically unsaturated species.

[104] The naphthoquinone and hydroxylamine can be added at any given point in a process and at one or more locations. For example, the antifouling composition can be added directly at the inter-coolers or compressors or upstream of the inter-coolers or compressors. The naphthoquinone and hydroxylamine can be added continuously or intermittently to the process equipment as required in order to inhibit or reduce fouling.

[105] The naphthoquinone and hydroxylamine can be introduced to desired systems by any suitable method. For example, it may be added in neat or a dilute solution. In some embodiments, a composition containing the naphthoquinone and hydroxylamine can be applied as a solution, emulsion, or dispersion that is sprayed, dripped, poured or injected into a desired opening within a system or onto the process equipment or process condensate. In some embodiments, the composition may be added with a wash oil or an attemperation water.

[106] After introducing the composition to process equipment, treated process equipment can be observed to have less deposition on equipment than in process equipment without addition of the composition. Reduction or inhibition in fouling can be evaluated by any known method or test. In some embodiments, the reduction or inhibition of fouling can be accessed by measuring the time it takes for a sample with and without the antifoulant composition to gel. See the Experimental section for further details.

[107] The following illustrative, non-limiting, examples are provided. Examples 1-5, 7- 10, and 12-14 detail preparation of components of the experimental compositions or show formulations for comparative purposes.

[108] The following abbreviations are used with reference to the following examples and disclosure in general: 1 ,4-naphthoquinone (1,4-NQ), 1 ,2-naphthoquinone (1,2-NQ), hydroxylamine (HA), N,N-diethylhydroxylamine (DEHA), piperidinol (Pipol), N- isopropylhydroxylamine (IPHA), A(A z -bis(2-hydroxypropylhydroxylamine (HPEIA), N,N- bis(2-hydroxy-2-phenylethyl)hydroxylamine (BHPhEHA), styrene, butadiene (BD), isoprene, methyl methacrylate (MMA), dibenzylhydroxylamine (DBzHA), 4-hydroxy- 2,2,6,6-trimethylpiperidinoxy (HTMPO), 2,4-dintro-6-sec-butylphenol (DNBP), 7-phenyl quinone methide (QMPh); comparative example (CE).

[109] Example 1: Styrene Polymerization with 400 ppm DEHA Treatment (CE)

[110] A styrene solution, 200g, having 400 ppm of DEHA was prepared. The stabilizer 4-ferf-butylcatechol stabilizer in the styrene solation was been removed just before the treatment composition. An alumina column was used for removal of said stabilizer. The reaction mixture was charged into a IL three-neck round-bottomed flask. A magnetic follower was added into the flask, after which a water-cooled condenser and a thermocouple were affixed onto two of the three necks. To remove the dissolved oxygen and preclude atmospheric oxygen from the flask, a nitrogen gas stream was flowed through the reaction mixture through a gas line in the third neck of the reaction flask. The loaded flask was placed onto a heating block that had been preheated to 1 15 °C. The commencement of the kinetics study was designated at the point at which the temperature of the reaction solution reached 115 °C. At this point, a sample was taken from the reaction mixture, diluted with toluene and the concentration of the polymer determined by a proprietary method. After 20 minutes, and every 20 minutes thereafter, a sample was taken from the flask and the amount of polymer determined as mentioned above. Results are shown in Table 1 and Figure 1.

[111] Example 2: Styrene Polymerization with 400 ppm 1,4-NQ Treatment (CE)

[112] A solution of freshly cleaned styrene, 200 g, with 400 ppm of 1 ,4-naphthoquinone was prepared. This solution was used to determine the effectiveness of 1 ,4- naphthoquinone as an antipolymerant using the procedure in Example 1. Results are shown in Table 1 and Figure 1.

[1 13] Example 3: Styrene Polymerization with 200 ppm of DEHA and 200 ppm of 1,4-NQ Treatment

[114] Using the procedure of Example 1 , a solution with 200 g of styrene with 200 ppm of DE14A and 200 ppm of d 1 ,4-naphthoquinone was prepared to determine the performance of the two antipolymerants used in conjunction with each other. Results are shown in Table 1 and Figure 1 . Using the combination of 1 ,4-NQ and DEHA, the inhibition of styrene polymerization was greater than expected in view of the results obtained when 1,4-NQ and DEHA were used individually at the same total concentration. For the purpose of comparison, an “expected” level of antipolymerant activity (in the absence of testing the inventive combination of 1 ,4-NQ and DEHA), at the 100 minute time point and based on the individual results would be 4.195 ((3.45 + 4.94)/2) % (w/w) polymer. However, inventive combination of 1,4-NQ and DEHA (used at 200 ppm each) at 100 minutes shows a level of polymerization of 0.58 % ((w/w) polymer), which is a significant and unexpected reduction in polymerization as compared to the predicted 4.195 value. This level of polymerization of 0.58 is approximately an 86% reduction as compared to the expected average of 4.195.

[115] Example 4: Styrene Polymerization with 400 ppm of DNBP (CE)

[116] A composition of freshly cleaned styrene, 200 g, and 400 ppm of DNBP was prepared and tested for antipolymerant kinetics according to the procedure of Example 1. Results are shown in Table 1 and Figure 1. [117] Table 1. Polystyrene concentration (w/w percent) from styrene polymerization kinetic studies under anaerobic conditions at 115 °C. Styrene reaction solutions were treated with 1,4-NQ, DEHA, the unexpected (e.g., synergistic) combination of DEHA and 1,4-NQ and, for comparison, DNBP.

[118] Example 5: Styrene Polymerization with 400 ppm Piperidinol Treatment

(CE)

[119] A solution of freshly cleaned styrene, 200 g, and 400 ppm of piperidinol was prepared and the antipolymerant reaction kinetics were tested using the procedure in Example 1. Results are shown in Table 2 and Figure 2.

[120] Example 6: Styrene Polymerization with 200 ppm of Piperidinol and 200 ppm of 1,4-NQ T reatment

[121] A solution of 200 g of styrene having of 200 ppm of piperidinol and 200 ppm of d 1 ,4-NQ was prepared for and the performance of the two antipolymerants used in combination was determined according to the procedure in in Example 1 . Results are shown in Table 2 and Figure 2. Using the combination of 1,4-NQ and piperidinol , the inhibition of styrene polymerization was greater than expected in view of the results obtained when 1,4-NQ and piperidinol were used individually at the same total concentration.

[122] Table 2. Polystyrene concentration (w/w percent) following kinetic studies under anaerobic conditions at 1 15 °C. Styrene reaction solutions were treated with 1 ,4-NQ, piperidinol, and the unexpected (e.g., synergistic)combination of 1 ,4-NQ and piperidinol. For comparison, DNBP was used.

[123] Example 7: Styrene Polymerization with 400 ppm DBzHA Treatment (CE)

[124] A solution of 200 g of freshly cleaned styrene with DBzHA antipolymerant dosed into the solution at 400 ppm concentration was tested for antipolymerant reaction kinetics was tested using the procedure in Example 1. Results are shown in Table 3 and Figure 3.

[125] Example 8: Styrene Polymerization with 200 ppm of DBzHA and 200 ppm of 1,4-NQ Treatment

[126] A solution of 200 g styrene, 200 ppm of DBzHA, and 200 ppm of 1,4-NQ was prepared the performance of the two antipolymerants used in combination was determined according to the procedure in in Example 1. Results are shown in Table 3 and Figure 3. Using the combination of 1,4-NQ and DBzHA, the inhibition of styrene polymerization was greater than expected in view of the results obtained when 1 ,4-NQ and DBzHA were used individually at the same total concentration.

[127] Table 3. Polystyrene concentration (w/w percent) during styrene polymerization kinetic studies under anaerobic conditions at 115 °C. The styrene reaction solutions were treated with 1,4-NQ, DBzHA, the unexpected (e.g., synergistic)combination of DBzHA and 1,4- 1 ,4-NQ. DNBP was used for comparison.