LOW-TEMPERATURE PROPERTIES OF DISTILLATE FUELS

AND COMPOSITIONS CONTAINING SAME

This application is directed to ester and ester/amide reaction products which are useful for improving the low-temperature properties of distillate fuels; to concentrates and to fuel compositions containing same.

Traditionally, the low-temperature properties of distillate fuels have been improved by the addition of kerosene, sometimes in very large amounts (5-70 wt %) . The kerosene dilutes the wax in the fuel, i.e. lowers the overall weight fraction of wax, and thereby lowers the cloud point, filterability temperature, and pour point simultaneously.

This invention seeks effectively to lower both the cloud point and CFPP (Cold Filter Plugging Point) of distillate fuel without any appreciable dilution of the wax component of the fuel. The novel esters and ester/amides prepared in accordance with this invention have been found to be surprisingly active wax crystal modifier additives for distillate fuels. Distillate fuel compositions containing ≤O.l wt % of such additives demonstrate significantly improved low-temperature flow properties, i.e. lower cloud point and lower CFPP filterability temperature.

Thus an object of this invention is to improve the low-temperature flow properties of distillate fuels. The reaction products of this invention are especially effective as additives in lowering the cloud point of distillate fuels, and thus improve the low-temperature flow properties of such fuels without the use of any light hydrocarbon diluent, such as kerosene. In addition, the filterability properties are improved as

demonstrated by lower CFPP temperatures. Thus, the reaction products of this invention demonstrate multifunctional activity in distillate fuels.

The reaction products of this invention are ester or ester/amide products which have core-pendant groups (star-like) structures derives from the reaction of an anhydride - or carboxylic acid - containing "core" - former with, as "pendant group" - former : (1) an amino alcohol, suitably the product of reaching an amine and an epoxide or (2) a combination of an amino alcohol and a secondary amine. Preferred anhydrides include pyromellitic dianhydride (PMDA) and benzophenone tetracarboxylic dianhydride (BTDA) .

More specifically, this invention provides a reaction product preparable by reacting : i) a compound comprising a hydrocarbyl anhydride group, or a hydrocarbyl carboxylic acid group, the latter having at least two carboxylic acid groups; with ii) an aminoalcohol; and iii) optionally, a secondary amine at a temperature from 85" to 250°C and a pressure from ambient to greater than autogenous to obtain the desired ester or ester/amide reaction product.

Component (i) may include a mixture of such compounds. Component (ii) may include a mixture of aminoalcohols and component (iii) , where present, may include a mixture of secondary amines; preferably it is the same secondary amine, or mixture of secondary amines, suitably fatty amines, used to prepare (ii) in accordance with the reaction : O

wherein R_, R_ and R_ are herein defined.

The reaction products of this invention have core-pendant group (star-like) structures. These reaction products are obtained by combining the core structure and the pendant group(s) in differing ratios using standard techniques for esterification/ a idification. These reaction products which are highly effective as wax crystal modifiers in lowering cloud point are generally characterized by the following structural features: (a) a compact "core" which forces close proximity of the pendant groups (pairs of adjacent carboxyl groups where the pendant groups are attached are generally separated by four or fewer atoms) ;

(b) a pendant group containing a high density of paraffin chains; and

(c) a pendant group structured in such a way as to allow facile parallel orientation of the attached paraffin chains.

Suitable core structures contain two or more reactive carboxyl groups (anhydrides, acids, or acid equivalents) . These structures include, but are not limited to, aromatic, alicyclic, aralkyl, alkaryl, and alkyl hydrocarbons, as well as their corresponding heteroatom-containing analogues. The reaction products of this invention are derived from "core" and "pendant group" precursors, and a range of reactant stoichiometries may be used. However, each reaction product requires one "core" derivatized with at least one aminoalcohol "pendant group"; any additional pendant groups may be either aminoalcohols or amines and may be added up to the limit of available reactive carboxyl groups in the core structure.

Reaction products of this invention may be grouped into categories based on distinct structural and compositional differences, described below.

Catecrory A: Aromatic "Core" (TABLE 2)

The preferred aminoalcohol, Entry 1, used in the synthesis of the reaction product of this invention, has low cloud point and CFPP activity by itself. Successful additives may be prepared from aromatic cores which are difunctional (e.g. phthalic anhydride, Entry 7) , trifunctional (e.g trimesic acid. Entries 3-6; trimellitic anhydride. Entries 14-16) , or tetrafunctional (e.g. tetrahydrofuran tetracarboxylic dianhydride, Entry 11) . The requirement that one pendant group must be an appropriate aminoalcohol is demonstrated by the amide analogues of PMDA (pyromellitic dianhydride; Entries 2, 12) and BTDA (benzophenonetetracarboxylic dianhydride; Entry 13) ; such analogues prepared without any aminoalcohol do not attain high cloud point activity. The requirement that the core functional groups allow the pendant groups to approach one another (i.e. carboxyl groups separated by no more that four atoms) is best demonstrated by the dicarboxyl benzene series (Entries 7-9) and by

2,6-naphthalene dicarboxylic acid (Entry 10). As the product ester groups move further apart, from two-carbon separation (Entry 7) to three-carbon separation (Entry 8) to four- and six- carbon separation (Entries 9 and 10) , the additive's cloud point activity falls from high activity to low activity.

A typical synthesis is illustrated by the preparation of the trimesate material (Entry 3) in EXAMPLE 25.

Category B: Bicyclic and Alicyclic "Cores" (TABLE 3)

Successful additives may be prepared from non-aromatic but relatively structurally rigid cores, such as bicyclics or alicyclics. Bicyclic cores may be difunctional (e.g. norbornene dicarboxylic anhydride,

Entry 17; camphoric acid, Entry 19), or tetrafunctional (e.g bicyclooctene tetracarboxylic dianhydride, Entry

18) . An example of a suitable alicyclic core is cyclohexane dicarboxylic anhydride (Entry 20) . A typical synthesis is illustrated by the preparation of the norbornene diester (Entry 17) in EXAMPLE 26.

Category C: Alkyl "Cores" (TABLE 3)

Successful additives may be prepared from non-rigid cores if the density of reactive groups is sufficiently high, i.e. if the core molecule is sufficiently small. For example, additives with good cloud point activity were derived from butyl citrate (Entry 21) , and from maleic anhydride (Entry 22) . By comparison, additives derived from large non-rigid alkyl cores such as dimer acid (Hystrene 3695, Entry 23) and trimer acid (Hystrene 5460, 60:40 mixture of trimer:dimer acids, Entry 24) offer little substantial cloud point activity.

A typical synthesis is illustrated by the preparation of the maleate ester (Entry 22) in EXAMPLE 27.

Category D: Multifunctional. Post-Reacted Additives

(TABLE 4) Multifunctional additives may be prepared from the cloud point additives of this invention, and may have advantages as ashless dispersants, detergents, antirust agents, antiwear agents, etc. Multifunctionality may be introduced into the core/pendant group additives whenever a suitably reactive group is available for post-reaction with a secondary chemical agent. In one approach, for example, judicious choice of core/pendant group stoichiometry may leave residual acid and/or anhydride groups available for post-reaction. This strategy was demonstrated with PMDA and BTDA derivatives (Entries 25-30, and 33-34) where only half of the available carboxyl groups were esterified with the aminoalcohol from Armeen 2HT/Vikolox 18, i.e. di(hydrogenated tallow)

amine/l,2-epoxy-C _lg alkane. Such materials were then post-reacted with (a) mono-capped polypropylene glycol (e.g. UCON LB-1145, average MW=2200, Entry 25-26), (b) amino-polyethers (e.g. Jeffamine M-600, mono-capped amine-terminated polypropylene oxide, MW=600, Entries 27-28; Surfonamine MNPA-380 amino polyether-capped nonylphenol, Entries 29-30) , and (c) polyethyleneamine (e.g. E-100, Entries 33-34). Entries 31-32 again demonstrate the low additive activities attained when the aminoalcohol component of the composition (in this case the adduct of Armeen 2HT/Vikolox 18) is absent.

In another approach, the secondary reactive functionality is chosen so as to be unreactive in the initial esterification process used to prepare the cloud point additive. For example (Entries 35-36) , maleic anhydride was esterified with the Armeen 2HT/Vikolox 18 aminoalcohol, and the remaining activated olefin was post-reacted via addition of the polyethyleneamine TEPA (tetraethylenepentaamine) . Preferred classes of reaction product of this invention have core-pendant group (star-like) structures derived from pyromellitic dianhydride (PMDA) or benzophenone tetracarboxylic diahydride (BTDA) or acid equivalents. For example, a general structure for the PMDA/aminoalcohol ester is as follows:

(PMDA)-(0-CH-CH ₂ -N-R ₁ )

^R 3 ^R 2 A general structure for the PMDA/aminoalcohol/amine ester/amide is as follows:

(PMDA)-(O-CH-O^-N-R.^ _y (N- ^ _z / / /

^R 3 ^R 2 ^R 2 A general structure for the PMDA/mixed aminoalcohol ester is as follows:

(PMDA) - (O-CH-CHg-N-R _j^ ) (O-CH-CH^N-R.^ _z i t I I

^R 3 ^R 2 ^R 4 ^R 2 A general structure for the PMDA/aminoetheralcohol ester is as follows:

(PMDA)-((0-CH-CH ₂ ) -O-CH-O^-N-R^ _χ

/ I I

R ₄ R ₃ R ₂

A general structure for the PMDA/aminoetheralcohol/amine ester/amide is as follows:

(PMDA)-((O-CH-CH.) -O-CH-CH.-N-R. )„(N-R. )Z

I i f f

^R 4 ^R 3 ^R 2 ^R 2

Where: x = y + z = 0.5-4 a = 1-3

R., R- = C ₈ -C ₅₀ linear hydrocarbyl groups, either saturated or unsaturated.

R ₂ = R ₂ , C ₁ -C ₁₀₀ hydrocarbyl

R. ■= H, .-C ₈ . hydrocarbyl Likewise, mutatic mutandis, for the reaction products obtained from BTDA.

Any suitable olefin oxide may be used. Epoxides are especially preferred. Included are such oxides as ethylene oxide, 1,2-epoxybutane, 1,2-epoxydecane, 1,2-epoxydodecane,

1,2-epoxytetradecane,1,2-epoxypentadecane,

1,2-epoxyhexadecane, 1,2-epoxyheptadecane, l,2-epoxyoctadecane,l,2-epoxyeicosane and the like and mixtures thereof and mixtures of C_ ₀ to C alpha olefin epoxides, mixtures of C . to C_ ₈ alpha olefin epoxides and the like.

Suitable amines, as indicated above, are secondary amines with at least one long-chain hydrocarbyl group, e.g. C ₈ to about C _5Q . Highly useful secondary amines include but are not limited to di(hydrogenated tallow) amine, ditallow amine, dioctadecylamine, methyloctadecylamine and the like.In this invention,

stoichiometries of amine to epoxide were chosen such that one amine reacted with each available epoxide functional group. Other stoichiometries where the amine is used in lower molar proportions may also be used.

The reactions can be carried out under widely varying conditions which are not believed to be critical. The reaction temperatures can vary from about 100 to 225°C, preferably 120 to 180"C, under ambient or autogenous pressure. However slightly higher pressures may be used if desired. The temperatures chosen will depend upon for the most part on the particular reactants and on whether or not a solvent is used. Solvents used will typically be hydrocarbon solvents such as xylene, but any non-polar, unreactive solvent can be used including benzene and toluene and/or mixtures thereof.

Molar ratios, less than molar ratios or more than molar ratios of the reactants can be used. Preferentially a molar ratio of 1:1 to about 8:1 of epoxide to amine is chosen.

The times for the reactions are also not believed to be critical. The process is generally carried out in from about one to twenty-four hours or more. In general, the reaction products of the present invention may be employed in any amount effective for imparting the desired degree of activity to improve the low temperature characteristics of distillate fuels. In many applications the products are effectively employed in amounts from about 0.001% to about 10% by weight and preferably from less than 0.01% to about 5% of the total weight of the composition.

These additives may be used in conjunction with other known low-temperature fuel additives (dispersants, etc.) being used for their intended purpose.

The fuels contemplated are liquid hydrocarbon combustion fuels, including the distillate fuels and fuel oils. Accordingly, the fuel oils that may be improved in accordance with the present invention are hydrocarbon fractions having an initial boiling point of at least about 250"F and an end-boiling point no higher than about 750°F and boiling substantially continuously throughout their distillation range. Such fuel oils are generally known as distillate fuel oils. It is to be understood, however, that this term is not restricted to straight run distillate fractions. The distillate fuel oils can be straight run distillate fuel oils, catalytically or thermally cracked (including hydrocracked) distillate fuel oils, or mixtures of straight run distillate fuel oils, naphthas and the like, with cracked distillate stocks. Moreover, such fuel oils can be treated in accordance with well-known commercial methods, such as, acid or caustic treatment, hydrogenation, solvent refining, clay treatment, etc.

The distillate fuel oils are characterized by their relatively low viscosities, pour points, and the like. The principal property which characterizes the contemplated hydrocarbons, however, is the distillation range. As mentioned hereinbefore, this range will lie between about 250"F and about 750°F. Obviously, the distillation range of each individual fuel oil will cover a narrower boiling range falling, nevertheless, within the above-specified limits. Likewise, each fuel oil will boil substantially continuously throughout its distillation range.

Contemplated among the fuel oils are Nos. 1, 2 and 3 fuel oils used in heating and as diesel fuel oils, and the jet combustion fuels. The domestic fuel oils generally conform to the specification set forth in

A.S.T.M. Specifications D396-48T. Specifications for diesel fuels are defined in A.S.T.M. Specification

D975-48T, Typical jet fuels are defined in Military Specification MIL-F-5624B.

The following Examples illustrate the invention.

EXAMPLE 1 Preparation of Additive 1

Di(hydrogenated tallow) amine (59.8 g, 0.12 mol; e.g. Armeen 2HT from Akzo Chemie) , and 1,2-epoxyoctadecane (32.2 g, 0.12 mol; e.g. Vikolox 18 from Viking Chemical) were combined and heated at 160"C for 16 hours. Pyromellitic dianhydride (6.54 g, 0.03 mol; e.g. PMDA from Allco Chemical Corp.), and xylene (approx. 30 ml) were added and heated at reflux (160-200°C) with azeotropic removal of water for 24 hours. Volatiles were then removed from the reaction medium at 190-200°C, and the reaction mixture was hot filtered to give 94.6 g of the final product as a low melting solid.

EXAMPLE 2 Preparation of Additive 2 According to the procedure used for Example 1

(above), di(hydrogenated tallow) amine (45.0 g, 0.09 mol), and 1,2-epoxyoctadecane (30.2 g, 0.112 mol) were first combined. Pyromellitic dianhydride (9.82 g, 0.045 mol) was then added, and allowed to react in the second step of the sequence. The final product (72.6 g) was obtained as a low-melting solid.

EXAMPLE 3 Preparation of Additive 3

According to the procedure used for Example 1 (above), di(hydrogenated tallow) amine (74.9 g, 0.15 mol), and 1,2-epoxyoctadecane (20.1 g, 0.075 mol) were first combined. Pyromellitic dianhydride (8.18 g, 0.0375 mol) was then added, and allowed to react in the

second step of the sequence. The final product (99.4 g) was obtained as a low-melting solid.

EXAMPLE 4 Preparation of Additive 4 According to the procedure used for Example 1

(above), di(hydrogenated tallow) amine (74.9 g, 0.15 mol), and 1,2-epoxyoctadecane (20.1 g, 0.075 mol) were first combined. Pyromellitic dianhydride (8.18 g, 0.0375 mol) was then added, and allowed to react in the second step of the sequence. The final product (99.4 g) was obtained as a low-melting solid.

EXAMPLE 5 Preparation of Additive 5

According to the procedure used for Example 1 (above), di(hydrogenated tallow) amine (62.4 g, 0.125 mol), and 1,2-epoxyoctadecane (21.0 g, 0.0781 mol) were first combined. Pyromellitic dianhydride (13.6 g, 0.0625 mol) was then added, and allowed to react in the second step of the sequence. The final product (85.5 g) was obtained as a low-melting solid.

EXAMPLE 6 Preparation of Additive 6

According to the procedure used for Example 1 (above), ditallow amine (49.8 g, 0.10 mol); e.g. Armeen 2T from Akzo Chemie) , and 1,2-epoxyoctadecane (28.2 g, 0.105 mol; e.g. Vikolox 18 from Viking Chemical) were first combined. Pyromellitic dianhydride (5.45 g, 0.025 mol) was then added, and allowed to react in the second step of the sequence. The final product (84.1 g) was obtained as a low-melting solid.

EXAMPLE 7 Preparation of Additive 7

According to the procedure used for Example 1 (above), ditallow amine (49.8 g, 0.10 mol), and 1,2-epoxyoctadecane (33.6 g, 0.125 mol) were first combined. Pyromellitic dianhydride (7.27 g, 0.033 mol) was then added, and allowed to react in the second step of the sequence. The final product (81.4 g) was obtained as a low-melting solid.

EXAMPLE 8

Preparation of Additive 8

According to the procedure used for Example 1 (above), ditallow amine (49.8 g, 0.10 mol), and 1,2-epoxyoctadecane (33.6 g, 0.125 mol) were first combined. Pyromellitic dianhydride (10.9 g, 0.050 mol) was then added, and allowed to react in the second step of the sequence. The final product (83.3 g) was obtained as a partly solidified solid.

EXAMPLE 9 Preparation of Additive 9

According to the procedure used for Example 1 (above), di(hydrogenated tallow) amine (40.0 g, 0.080 mol), and 1,2-epoxyeicosane (28.7 g, 0.088 mol; e.g. Vikolox 20 from Viking Chemical) were combined at 220°C. Pyromellitic dianhydride (9.60 g, 0.044 mol) was then added, and allowed to react in the second step of the sequence. The final product (69.8 g) was obtained as a low-melting solid.

EXAMPLE 10 Preparation of Additive 10

According to the procedure used for Example 1 (above), di(hydrogenated tallow) amine (40.0 g, 0.080 mol) , and a mixture of C__-C_ . alpha olefin epoxides (30.4 g, 0.088 mol; e.g. Vikolox 20-24 from Viking

Chemical) were combined at 220°C. Pyromellitic dianhydride (9.60 g, 0.044 mol) was then added, and allowed to react in the second step of the sequence. The final product (70.9 g) was obtained as a low-melting solid.

EXAMPLE 11 Preparation of Additive 11

According to the procedure used for Example 1 (above), di(hydrogenated tallow) amine (35.0 g, 0.070 mol) , and a mixture of ^C ₂ ~ ^C ₈ ^al P ^ha °l ^ef in epoxides (33.7 g, 0.077 mol; e.g. Vikolox 24-28 from Viking Chemical) were combined at 220"C. Pyromellitic dianhydride (8.40 g, 0.0385 mol) was then added, and allowed to react in the second step of the sequence. The final product (69.0 g) was obtained as a low-melting solid.

EXAMPLE 12 Preparation of Additive 12

Di(hydrogenated tallow) amine (50.0 g, 0.10 mol), and 1,2-epoxyoctadecane (33.6 g, 0.125 mol) were combined and heated at 150°C for 16 hours. To the cooled reaction mixture was added potassium t-butoxide (0.56 g, 0.005 mol), and 1,2-epoxybutane (13.5 g, 0.187 mol). The mixture was heated to 105-115°C for 20 hours, to 150°C for 1 hour, followed by removal of all volatiles at 150°C. Pyromellitic dianhydride (6.00 g, 0.0275 mol), and xylene (approx. 50 ml) were added and heated at reflux (180-190 ^β C) with azeotropic removal of water for 6 hours. Volatiles were then removed from the reaction medium at 180-190°C, and the reaction mixture was hot filtered to give 83.5 g of the final product as a low-melting solid.

EXAMPLE 13 Preparation of Additive 13

Di(hydrogenated tallow) amine (30.0 g, 0.060 mol), and 1,2-epoxyoctadecane (16.1 g, 0.060 mol) were combined and heated at 150°C for 24 hours. To the cooled reaction mixture was added potassium t-butoxide (0.17 g, 0.0015 mol), and 1,2-epoxybutane (5.41 g, 0.075 mol). The mixture was heated to 105-115°C for 20 hours, followed by removal of all volatiles at 150°C. Pyromellitic dianhydride (7.20 g, 0.033 mol), di(hydrogenated tallow) amine (30.0 g, 0.060 mol), and xylene (approx. 50 ml) were added and heated at reflux (180-190°C) with azeotropic removal of water for 24 hours. Volatiles were then removed from the reaction medium at 180-190°C, and the reaction mixture was hot filtered to give 76.2 g of the final product as a low-melting solid.

EXAMPLE 14 Preparation of Additive 14 Di(hydrogenated tallow) amine (60.0 g, 0.12 mol), and 1,2-epoxyoctadecane (20.1 g, 0.075 mol) were combined and heated at 150°C for 24 hours. The reaction mixture (above) and 1,2-epoxybutane (13.0 g, 0.180 mol), was heated in a sealed glass pressure bottle at 170-190°C for 7 hours, under autogenous pressure. Volatiles were removed at 150 ^β C/atm. pressure. To this was added pyromellitic dianhydride (7.20 g, 0.033 mol), and xylene (approx. 50 ml) followed by heating at reflux (180-190°C) with azeotropic removal of water for 24 hours. Volatiles were then removed from the reaction medium at 180-190"C, and the reaction mixture was hot filtered to give 78.4 g of the final product as a low-melting solid.

EXAMPLE 15 Preparation of Additive 15

Di(hydrogenated tallow) amine (50.0 g, 0.10 mol; e.g. Armeen 2HT from Akzo Chemie) , and 1,2-epoxyoctadecane (33.6 g, 0.125 mol; e.g. Vikolox 18 from Viking

Chemical) were combined and heated at 160 ^β C for 24 hours. Benzophenone tetracarboxylic dianhydride (8.86 g, 0.0275 mol; e.g. BTDA from Allco Chemical Corp.), and xylene (approx. 50 ml) were added and heated at reflux (180-220°C) with azeotropic removal of water for 24 hours. Volatiles were then removed from the reaction medium at 180-220°C, and the reaction mixture was hot filtered to give 71.9 g of the final product as a low-melting solid.

EXAMPLE 16

Preparation of Additive 16

According to the procedure used for Example 15 (above), di(hydrogenated tallow) amine (50.0 g, 0.10 mol), and 1,2-epoxyoctadecane (33.6 g, 0.125 mol) were first combined. Benzophenone tetracarboxylic dianhydride (10.7 g, 0.0333 mol) was then added, and allowed to react in the second step of the sequence. The final product (86.4 g) was obtained as a low-melting solid.

EXAMPLE 17

Preparation of Additive 17

According to the procedure used for Example 15 (above), di(hydrogenated tallow) amine (50.0 g, 0.10 mol), and 1,2-epoxyoctadecane (33.6 g, 0.125 mol) were first combined. Benzophenone tetracarboxylic dianhydride (16.1 g, 0.050 mol) was then added, and allowed to react in the second step of the sequence. The final product (87.2 g) was obtained as a low-melting solid.

EXAMPLE 18 Preparation of Additive 18

According to the procedure used for Example 15 (above), di(hydrogenated tallow) amine (62.4 g, 0.125 mol), and 1,2-epoxyoctadecane (21.0 g, 0.078 mol) were first combined. Benzophenone tetracarboxylic dianhydride (11.1 g, 0.0343 mol) was then added, and allowed to react in the second step of the sequence. The final product (86.6 g) was obtained as a low-melting solid.

EXAMPLE 19 Preparation of Additive 19 According to the procedure used for Example 15 (above), di(hydrogenated tallow) amine (62.4 g, 0.125 mol), and 1,2-epoxyoctadecane (21.0 g, 0.078 mol) were first combined. Benzophenone tetracarboxylic dianhydride (14.8 g, 0.0458 mol) was then added, and allowed to react in the second step of the sequence. The final product (89.8 g) was obtained as a low-melting solid.

EXAMPLE 20 Preparation of Additive 20

According to the procedure used for Example 15 (above), 4 g, 0.125 mol), and 1,2-epoxyoctadecane (21.0 g, 0.078 mol) were first combined. Benzophenone tetracarboxylic dianhydride (22.2 g, 0.0687 mol) was then added, and allowed to react in the second step of the sequence. The final product (95.2 g) was obtained as a low-melting solid.

EXAMPLE 21

Preparation of Additive 21

According to the procedure used for Example 15 (above), ditallow amine (49.8 g, 0.10 mol), e.g. Armeen 2T from Akzo Che ie) , and 1,2-epoxyoctadecane (33.6 g, 0.125 mol) were first combined. Benzophenone

tetracarboxylic dianhydride (8.86 g, 0.0275 mol) was then added, and allowed to react in the second step of the sequence. The final product (81.8 g) was obtained as a low-melting solid.

EXAMPLE 22

Preparation of Additive 22

According to the procedure used for Example 15 (above), di(hydrogenated tallow) amine (40.0 g, 0.080 mol), and 1,2-epoxyeicosane (28.7 g, 0.088 mol); e.g. Vikolox 20 from Viking Chemical) were combined at

220°C. Benzophenone tetracarboxylic dianhydride (14.2 g, 0.044 mol) was then added, and allowed to react in the second step of the sequence. The final product (71.2 g) was obtained as a low-melting solid.

EXAMPLE 23

Preparation of Additive 23

According to the procedure used for Example 15 (above), di(hydrogenated tallow) amine (40.0 g, 0.080 mol) , and a mixture of C_ ₀ -C ₂₄ alpha olefin epoxides (30.4 g, 0.088 mol; e.g. Vikolox 20-24 from Viking Chemical) were combined at 220°C. Benzophenone tetracarboxylic dianhydride (14.2 g, 0.044 mol) was then added, and allowed to react in the second step of the sequence. The final product (75.1 g) was obtained as a low-melting solid.

EXAMPLE 24 Preparation of Additive 24

According to the procedure used for Example 15 (above), di(hydrogenated tallow) amine (35.0 g, 0.070 mol) , and a mixture of C ₂ .-C ₂₈ alpha olefin epoxides (33.7 g, 0.077 mol; e.g. Vikolox 24-28 from Viking Chemical) were combined at 220°C. Benzophenone tetracarboxylic dianhydride (12.4 g, 0.0385 mol) was then added, and allowed to react in the second step of

the sequence. The final product (74.2 g) was obtained as a low-melting solid.

EXAMPLE 25 Preparation of Additive Entry 3 Di(hydrogenated tallow) amine (50.0 g, 0.10 mol; e.g. Armeen 2HT from Akzo Chemie) , and

1,2-epoxyoctadecane (33.6 g, 0.125 mol; e.g. Vikolox 18 from Viking Chemical) were combined and heated at 160 ^β C for 17 hours. Trimesic acid (7.71 g, 0.037 mol; e.g. from Amoco Chemical Co.), and xylene (approx. 60 ml) were added and heated at reflux (180-240°C) with azeotropic removal of water for 8 hours. Volatiles were then removed from the reaction medium at 190-200 ^β C, and the reaction mixture was hot filtered to give the final product.

EXAMPLE 26 Preparation of Additive Entry 17

Di(hydrogenated tallow) amine (50.0 g, 0.10 mol; e.g. Armeen 2HT from Akzo Chemie) , and 1,2-epoxyoctadecane (33.6 g, 0.125 mol; e.g. Vikolox 18 from Viking Chemical) were combined and heated at 160°C for 17 hours. Norborene dicarboxylic anhydride (9.03 g, 0.055 mol; e.g. from Aldrich Chemical Co.), and xylene (approx. 60 ml) were added and heated at reflux (180-250°C) with azeotropic removal of water for 8 hours. Volatiles were then removed from the reaction medium at 190-200°C, and the reaction mixture was hot filtered to give the final product.

EXAMPLE 27 Preparation of Additive Entry 22

Di(hydrogenated tallow) amine (50.0 g, 0.10 mol; e.g. Armeen 2HT from Akzo Chemie), and 1,2-epoxyoctadecane (33.6 g, 0.125 mol; e.g. Vikolox 18 from Viking Chemical) were combined and heated at 190°C for 19

hours. Maleic anhydride (5.88 g, 0.060 mol; e.g. from Aldrich Chemical Co.), and xylene (approx. 60 ml) were added and heated at reflux (185-190°C) with azeotropic removal of water for 22 hours. Volatiles were then removed from the reaction medium at 190°C, and the reaction mixture was hot filtered to give 81.1 g of the final product.

EXAMPLE 28 Preparation of Additive Entry 29 Di(hydrogenated tallow) amine (50.0 g, 0.10 mol; e.g. Armeen 2HT from Akzo Chemie), and 1,2-epoxyoctadecane (33.6 g, 0.125 mol; e.g. Vikolox 18 from Viking Chemical) were combined and heated at 170°C for 22 hours. Benzophenone tetracarboxylic dianhydride (17.7 g, 0.055 mol; e.g. BTDA from Allco Chemical Corp.), and xylene (approx. 60 ml) were added and heated at reflux (185-190°C) with azeotropic removal of water for 4.5 hours. Jeffamine M-600 (31.5 g, 0.0525 mol; e.g. a mono-capped amine-terminated polypropylene oxide, from Akzo Chemie) was added and heated at 180°C for 19 hr with azeotropic removal of water. Volatiles were ^~ tnen removed from the reaction medium at 180°C, and the reaction mixture was hot filtered to give 112.7 g of the final product. Preparation of Additive Concentrate

A concentrate solution of 100 ml total volume was prepared by dissolving 10 g of additive in mixed xylenes solvent. Any insoluble particulates in the additive concentrate were removed by filtration before use. Generally speaking however, each 100 ml of concentrate solution may contain from about 1 to about 50 grams of the additive product of reaction.

The cloud point of the additized distillate fuel was determined using two procedures: (a) an automatic cloud point test based on the commercially available Herzog cloud point tester; test cooling rate is approximately l°C/min. Results of this test protocol correlate well with ASTM D2500 methods. The test designation (below) is "HERZOG." (b)an automatic cloud point test based on the equipment /procedure detailed in U.S. 4,601,303; the test designation (below) is AUTO CP.

The low-temperature filterability was determined using the Cold Filter Plugging Point (CFPP) test. This test procedure is described in "Journal of the Institute of Petroleum," Volume 52, Number 510, June 1966, pp. 173-185.

Test results may be found in the TABLE 1 below.

TABLE 1 ADDITIVE EFFECTS ON THE CLOUD POINT AND FILTERABILITY (CPFF) OF DISTILLATE FUEL (ADDITIVE CONCENTRATION = 0.1WT%)

Im rovement in Performance Tem erature °F

A concentrate solution of 100 ml total volume was prepared by dissolving 10 g of reaction product in mixed xylenes solvent. Any insoluble particulates in the additive concentrate were removed by filtration before use. Test Fuels

Two test fuels were used for the screening of additive activity:

The cloud point of the additized distillate fuel was determined using an automatic cloud point test based on the commercially available Herzog cloud point tester; test cooling rate is approximately l°C/min. Results of this test protocol correlate well with ASTM D2500 methods. The test designation (below) is "HERZOG."

The low-temperature filterability was determined using the Cold Filter Plugging Point (CFPP) test. This test procedure is described in "Journal of the Institute of Petroleum," Volume 52, Number 510, June 1966, pp. 173-185.

Test results may be found in TABLES 2-4 below. The products of this invention represent a significant new generation of wax crystal modifier additives which are dramatically more effective than many previously known additives. They represent a viable alternative to the use of kerosene in improving diesel fuel low-temperature performance.

TABLE 2

Gore Pendant Group Structures

Category A: Arcπatic, He erocyclic Gores

Mole

Entry Pendant Grou s ore Ratio

1 1/1.25 2 4/1 3 3/3.75/1.1 4 3/2/1 5 2/2/1 6 2/1/1 7 2/2.5/1.1 8 2/2.5/1 9 2/2.5/1 10 2/2.5/1

11 2/2.5/1.1 6.9

12 2/1.1 2.2 0 13 2/1.1 1.3 -2

Fuel B; 500 pp Additive

14 Armeen 2HT/Vikolox 18 Trimellitic Arihy 3/3/1 3.6 4

15 Armeen 2HT/Vikolox 18 Trimellitic Arihy 2/2/1 3.3 2

16 Armeen 2HT/Vikolox 14-20 Trimellitic Arihy 3/3/1 3.6 4

TABLE 3 Oαnε Bεndaπt Group Structures Categories B, C, (See below)

Performance Iirprovement (F)

Mole Cloud Point

Entry Pendant Group(s) Core Ratio (HERZOG) CFPP

Category B; "Bicyclic &

Alicyclic Oαres ⁿ luel A; 1000 pp Additive

17 Armeen 2HT/Vikolox 18

18 Armeen 2HT/Vikolox 18

19 Armeen 2HT/Vikolox 18 2

20 Armeen 2HT/Vilolox 18 4

Category C; "Alkyl Oore" Fuel A; 1000 ppn Additive

6 7 2 4

TABLE 4