FIELD OF INVENTION

The invention relates to reducing the 1 ,4-dioxane by-product which is formed during the sulfation of alkoxylates through the use of alkoxylates that have been prepared using a double metal cyanide (DMC) catalyst.

BACKGROUND OF INVENTION

The use of a double metal cyanide (DMC) catalyst can be an effective method to reduce the percentage of both polyethylene glycol (PEG) and high EO-mole alkoxylated alcohols (HEmAA) during the synthesis of alcohol ethoxylates. Both large quantities of PEG and HEmAA can contribute to high quantities of 1 ,4-dioxane in the alkoxylate during subsequent sulfation reactions (e.g. preparation of sodium lauryl ether sulfates).

Alcohol ethoxylates are commonly prepared in large commercial quantities via the polymerization of the ethylene oxide in the presence of a catalyzed initiator. Typical initiators contain an active free hydrogen, such as a primary or secondary hydroxyl functional group, which can be catalyzed using an alkaline catalyst. Common alkaline catalysts, including potassium hydroxide and sodium hydroxide, will deprotonate this active hydrogen, resulting in a highly active nucleophilic initiating species. Once the ethylene oxide is added into the reactor, this active nucleophile will undergo ring opening polymerization the epoxide monomer to give the resulting alcohol ethoxylate.

During the preparation of the alcohol ethoxylate, several key criteria contribute to the polyether’s purity, safety and potential for use as a reactant in a sulfation reaction. For instance, the formation of 1 ,4-dioxane during the ethoxylation of alkaline catalyzed alcohol ethoxylates can be a potential health hazard for those who intend to use these products. 1 ,4-dioxane is generally considered a health and environmental hazard for use in products. Several programs classify 1 ,4-dioxane as a potential human carcinogen.

Additionally, the presence of water in the alkaline catalyst can result in the formation of polyethylene glycol (PEG) in the alcohol ethoxylate product. The amount of water, its ratio to the monomer and the reaction conditions will determine the amount and molecular weight of the PEG in the alcohol ethoxylate. The presence of PEG can negatively impact the sulfation reaction with the alcohol ethoxylate, as PEG is readily converted to 1 ,4-dioxane in the presence of SO3, and is thus, considered to be a health concern for products containing sulfated alcohol ethoxylates. Lastly, the distribution of ethoxymers in the resulting alcohol ethoxylate can impact the quality of the alcohol ethoxylate product. The alkaline-catalyzed ethoxylation of alcohols typically results in a broad distribution of ethoxylated alcohols (referred to as ethoxymers). This broad distribution tends to have elevated amounts of unreacted alcohol, as well as increased fractions of low mole- ethoxymers and high mole-ethoxymers. The increased presence of the unreacted free-alcohol and low mole ethoxymers in alkaline-catalyzed alcohol ethoxylates can adversely affect the physical properties from the sulfated alcohol ethoxylate (for instance different salt-thickened viscosity profile). Further, the presence of high EO-mole alkoxylated alcohols (HEmAA) could promote the formation of 1 ,4-dioxane during the sulfation reaction of alcohol ethoxylates.

Several programs classify 1 ,4-dioxane as a potential human carcinogen, which increases the need for its reduced levels in products such as alkyl ether sulfates. Since 1 ,4-Dioxane is an undesirable by-product of the sulfation process and is generally considered a health and environmental hazard for use in products, it is desirable to find methods to reduce its formation during the sulfation of alcohol ethoxylates.

1 ,4-Dioxane is formed during the sulfation process as a consequence of several factors, including sulfation equipment, the reaction conditions (molar ratios, loading rates, etc.) and the feedstock of the alkoxylate. Controlling the sulfation equipment and reaction conditions can help to reduce the formation of 1 ,4-dioxane. However, using an improved alkoxylate feedstock will further help to reduce the amount of 1 ,4-dioxane that is formed during the sulfation process. Factors that relate the quality of the alkoxylate feedstock to the formation of 1 ,4-dioxane during the sulfation process include the presence of moisture, elevated amounts of polyethylene glycol (PEG) and increased quantities of high-mole alkoxylated material (in particular high mole-ethoxylates).

A proposed method to improve the quality of the feedstock of the alcohol ethoxylate is to synthesize the alcohol ethoxylate feedstock via a DMC-mediated catalysis. Alcohol ethoxylates that are catalyzed with DMC exhibit properties that are beneficial to the production of a sulfated alcohol ethoxylate that has a reduced fraction of 1 ,4-dioxane. The improved qualities of the alcohol ethoxylate feedstock include (a) reduced amounts of residual water in the product, (b) lower levels of unreacted/free-alcohol, (c) decreased amounts of PEG (as compared to the KOH- catalyzed system), and (d) a reduced fraction of HEmAA in the final ethoxylated feedstock. SUMMARY OF INVENTION

The present disclosure illustrates that the use of a double metal cyanide (DMC) catalyst can be an effective method to reduce the amounts of residual water, unreacted/free-alcohol, polyethylene glycol (PEG) and high EO-mole alkoxylated alcohols (HEmAA) during the synthesis of alcohol ethoxylates. Increased quantities of water, PEG and HEmAA can contribute to high quantities of 1 ,4-dioxane during subsequent sulfation reactions to the alkoxylate (e.g. preparation of sodium lauryl ether sulfates).

The present disclosure attempts to solve the need of the formation of 1 ,4-dioxane during the sulfation of an alcohol ethoxylate comprising of the following structure: where R is selected from a variety of saturated or unsaturated, linear or branched, C6-C22 alkyl groups. In the preferred embodiment, the alcohol ethoxylated can be made from a tert-butyl alcohol complexed-double metal cyanide (DMC) catalyst. When compared to ethoxylates that have been prepared with traditional alkaline catalysts (i.e. potassium hydroxide and sodium hydroxide), alcohol ethoxylates made with the DMC-catalytic system generally produce ethoxylates with (a) reduced amounts of residual water in the product, (b) lower levels of unreacted/free-alcohol, (c) decreased amounts of PEG, and (d) a reduced fraction of HEmAA in the final ethoxylated feedstock. It is this DMC-catalyzed ethoxylated feedstock that can be used in subsequent sulfation reactions to produce ethoxylated-sulfates for use as a detergent, personal care and/or home care cleaning products.

Through the use of a DMC catalyst, the formation of 1 ,4-dioxane can be reduced during the sulfation reaction of alcohol ethoxylates and sulfation reactants (i.e. chlorosulfonic acid, sulfamic acid and sulfur trioxide) because the amount of water, PEG and HEmAA have been significantly reduced in the ethoxylated feedstock. Comparing the by-products from the sulfation reaction with chlorosulfonic acid, the amount of 1 ,4-dioxane was diminished, regardless of the loading of either catalyst in the alcohol ethoxylate feedstock. The usefulness of the DMC catalytic system affords an alcohol feedstock for sulfation that has a lower polydispersity than systems that are based on traditional alkaline catalysts. This reduction in range of oligomeric species that is gained via the DMC catalyst has surprisingly resulted in a reduction of 1 ,4-dioxane during the sulfation of the ethoxylate. The production of the 1 ,4-dioxane can be reduced by nearly half when the ethoxylate feedstock is prepared using the DMC catalytic system over a potassium hydroxide catalyst. This benefit reduces the need to remove 1 ,4-dioxane from typical sulfated alcohol ethoxylates that are commonly used in personal care and cleaning markets.

DETAILED DESCRIPTION OF THE INVENTION

The subject matter of the present disclosure is a process for which alcohol ethoxylates with low fraction of PEG and HEmAA are prepared via the use of a tert-butyl alcohol complexed-double metal cyanide (DMC) catalyst. Alcohol ethoxylates prepared using this catalytic system resemble identical polyethers that have been prepared via a more traditional catalytic system (i.e. potassium hydroxide). For instance, they have identical similar structural conformation (as determined via FTIR and HNMR), they can have identical hydroxyl values, and similar cloud points.

However, there are some unique differences between the methods of catalysis between identical products, including a propensity for decreased concentrations of residual water, lower amounts of polyethylene glycol (PEG) and a reduced fraction of the high EO-mole alkoxylated alcohols (HEmAA) with samples that have been prepared via the DMC-catalyzed mechanism. While these differences have some predictable outcomes to the physical properties of identical alcohol ethoxylates, such as a high surface tension for DMC-catalyzed systems, the differences in the amount of water, PEG and HEmAA have also been shown to reduce the amount of 1 ,4-dioxane when the alcohol ethoxylate is used as a feedstock for the sulfation of its active hydrogen.

Alcohol ethoxylates are commonly prepared in large commercial quantities via the polymerization of ethylene oxide in the presence of a catalyzed initiator. Typical initiators contain an active free hydrogen, such as a primary or secondary hydroxyl functional group, which can be catalyzed using an alkaline catalyst. Common alkaline catalysts, including potassium hydroxide and sodium hydroxide, will deprotonate this active hydrogen, resulting in a highly active nucleophilic initiating species. Once the ethylene oxide is added into the reactor, this active nucleophile will undergo ring opening polymerization the epoxide monomer to give the resulting alcohol ethoxylate.

Double metal cyanide (DMC) catalysts can be used to catalyze the reaction between epoxides and compounds that contain a free active hydrogen. The kinetics of this reaction are surprisingly rapid as compared to the alkoxylation kinetics of an alkaline-catalyzed system (i.e. potassium hydroxide and sodium hydroxide). Typically, the concentration of the DMC catalyst can be between 5 and 1000 ppm of the product to be produced. Double metal cyanide catalysts are prepared as complexes of low molecular weight organic ligands with a double metals cyanide salt (e.g. zinc hexacyanocolbaltate).

Metallic entities and double metal cyanide salts that are useful in the production of the DMC catalyst are described, for example in US-4,500,704, and include: Zinc hexacyanoferrate (EH), Zinc hexacyanoferrate (II), nickel (II) hexacyanoferrate (II), nickel(ll) hexacyanoferrate (III), Zinc hexacyanoferrate (III) hydrate, cobalt(ll) hexacyanoferrate (II), nickel(ll) hexacyanoferrate (III) hydrate, ferrous hexacyanoferrate (III), cobalt (II) hexacyanocobaltate (III), zinc hexacyanocobaltate (II), Zinc hexacyanomanganate (II), Zinc hexacyanochromate (III), Zinc iodopentacyanoferrate (III), cobalt (II) chloropentacyanoferrate (II), cobalt (II) bromopentacyanoferrate (II), iron (II) fluoropentacyanoferrate (II), Zinc chlorobromotetracyanoferrate (III), iron (III) hexacyanoferrate (III), aluminum dichlorotetracyanoferrate (III), molybdenum (IV) bromopentacyanoferrate (II), molybdenum (VI) chloropentacyanoferrate (II), Vanadium (IV) hexacyanochromate (II), vanadium (V) hexacyanoferrate (III), strontium (II) hexacyanomanganate (III), tungsten (IV) hexacyano Vanadate (IV), aluminumchloropentacyano Vanadate(V), tungsten (VI) hexacyanoferrate (III), manganese (II) hexacyanoferrate (II), chromium (III) hexacyanoferrate (III), and so forth. Still Other cyanide complexes can also be used such as Zn[Fe(CN) NO], Zn ₃ [Fe(CN) N0 ₂ ] ₂ , Zn[Fe (CN) ₅ CO], Zn(Fe(CN) ₅ H ₂ 0), Fe[Fe(CN) ₅ OH], Cr[Fe(CN) ₅ NCO), Cr[Fe(CN) ₅ NCS),

AI(CO(CN) CNO), Ni3[Mn(CN) CNS]2, and the like. Preferably, the double metal cyanide salt is the zinc hexacyanocolbaltate.

The DMC catalyst is typically complexed with a small organic ligand. Common organic complexing agents include alcohols, aldehydes, ketones, ethers, amides, nitriles, sulfides, and the like. A list of useful organic complexing ligand is shown, for example, in US-6,642,423 B2. Preferably, the preferred organic complexing ligand is tert-butyl alcohol.

Use of a DMC catalysts during the production of alkoxylates has been shown to reduce the amount of PEG in the finished alkoxylation product as compared to alkoxylates that have been prepared by alkaline catalysis (such as potassium hydroxide and sodium hydroxide). Due to the mechanism of DMC’s catalysis of the alkoxylation of aliphatic alcohols, a narrower distribution of product is also observed. Consequences of having a narrower distribution include having reduced quantities of (A) unreacted free aliphatic alcohol, (B) low EO-mole alkoxylates (LEmAA) and (C) high EO-mole alkoxylates (HEmAA). The first key criteria to having a narrower distribution is that the alcohol ethoxylate has a reduced quantity of unreacted/free aliphatic alcohol present in the final product. The use of the DMC catalyst reduces the amount of unreacted material as illustrated by a reduced levels of free active hydrogen organic compounds (i.e. unreacted/free alcohol), as well as low levels of 1 ,4-dioxane are present in the final product.

A second key criteria to having a narrow distribution is having reduced amounts of low mole and high mole ethoxymers within the final product. More dispersed polyethers can be prepared when using a DMC-catalyst that uses the complexing agents of tert-butyl-alcohol (t-BuOH) or polypropyleneglycol-700 (PPG-700). Park et. at. (Polymer 44 L 1 (2003): 3417-3428) discovered that polydispersity indices (M _w /M _n , PDI) in the range of 1 .29-1 .59 are obtained when using DMC catalysts that have been complexed with either t-BuOH or PPG-700. Park attributed the broadening of the polydispersity to a “more active isomerization and chain transfer reactions” that are accompanied by the presence of either t-BuOH or PPG-700.

Surprisingly, when using a DMC catalyst, a narrow distribution is obtained when synthesizing a polyether from primary and secondary alcohols. When exposing initiating alcohols such as nonanol, decanol (and branched-isomers thereof), undecanol (and branched-isomers thereof), dodecanol, tridecanol (and branched-isomers thereof), tetradecanol, pentadecanol, hexadecanol, octadecanol (and branched-isomers thereof), 2-propyl-heptanol, 2-ethyl-hexanol and castor oil, to ethylene oxide in conjunction with a DMC-catalyst that has been complexed with t-BuOH, polyethers with relatively narrow distributions are obtained.

This is a sharp contrast when comparing their PDIs of samples that are obtained using a traditional alkaline catalyst such as potassium hydroxide or sodium hydroxide. The distributions of the ethoxymers are very different when comparing the KOH and DMC catalytic systems (Figure 1 - Figure 5). Alcohol polyethers that are catalyzed with DMC demonstrate a much narrower distribution as compared to the polyethers that were synthesized using KOH.

Further exemplifying the differences in the distributions between the traditional alkaline catalyst (e.g., KOH) and the DMC-catalyzed alcohol ethoxylates resides in the amount of HEmAA that is present in the final solution. For the purposes of this specification, the term HEmAA means high EO-mole alkoxylated alcohol. More specifically, the term ‘high EO-mole’ refers to the adducts in which the average number of moles of EO, n, is equal to or greater than n+4. An example of HEmAA can be illustrated with the alcohol ethoxylate of Laureth-7, in which n is the average number of moles of EO on the alcohol, and is equal to 7. The HEmAA for Laureth-7 is considered to be any adduct in which n ³ 11. The amount of HEmAA can be quantified by experimentally determining the composition percentage of the product that has an ethoxylation value of n+ 4. In this instance, ‘ri refers to the average number of moles of polyoxyethylene that is present on the alcohol after the ethoxylation process. A value of n+4 is considered to be representative of the HEmAA when /7-values ranges from 1 to 20. The sum of the composition percentage that exists above n+4 is quantifiable and is consistently lower for alcohol ethoxylates that are prepared via DMC catalysis as compared to KOH catalysis.

An additional advantage of using a DMC-mediated ethoxylation of alcohols is the reduced amount of polyethylene glycol (PEG) in the final product, as compared to alkaline catalysis. Traditional alkaline catalysts such as potassium and sodium hydroxide are commonly dissolved in water to increase safety and reduce the hardships of transportation into a reactor vessel. The presence of water in these catalysts require that a stringent dewatering step prior to alkoxylation because the presence of water will result in the formation of PEG during ethoxylation (or the PPO homopolymer during propoxylation). The presence of PEG alters the appearance and performance of the alcohol ethoxylate product because it can phase separate from the more hydrophobic species and also reduces concentration the active components, respectively.

The presence of PEG can adversely affect the usability of polypropylene oxide (PPO) polyols, as it can change the predicted molar ratio of hydroxyl-to-isocynate, which is a critical factor during the formation of polyurethanes. PEG is commonly produced in a PPO polyol during the ΈO- capping’ of PPO-polyols. It is common to ‘cap’ a PPO polyol with ethylene oxide (EO) in order to increase the polyol’s reactivity for the synthesis of polyurethanes. Unfortunately, DMC cannot be used to catalyze this EO-capping of PPO polyols because it leaves a mixture of two products, (A) a major fraction unreacted PPO and (B) a minor fraction of highly ethoxylated PPO. This results in a polyol with a low degree of primary hydroxyl groups, which can be an undesirable functionality in a polyol product (for instance, polyurethane production). Nevertheless, EO capping can be accomplished using a KOH catalyst via the re-catalysis method, in which the DMC-initiated polyol is then ‘poisoned’ with KOH, stripped to remove water and then exposed to EO for terminal capping.

The reason for DMC’s inability to EO-cap PPO polyols is commonly attributed to the (i) hydrophilicity of the ethoxylated PPO polyol, (ii) the molecular weight of the PPO polyols and (iii) the reduced reactivity of the terminal secondary alcohols associated with PPO, that is to say DMC will preferentially react EO with the newly formed primary alcohol (i.e. the first EO moiety). The increased hydrophilicity of the associated ethoxylated PPO polyol has been considered to be an attributing factor in the EO-capping of PPO polyols. As the first mole of EO is added to the PPO polyol, the hydrophilicity of the that particular PPO polyol is slightly enhanced, which increases the catalyst’s proclivity for the more hydrophilic active site. An increased preference for hydrophilic sites results in DMC’s tendency to produce a higher degree of ethoxylation at that particular site, ultimately resulting in minor fraction of either high molecular weight polyethylene homopolymer (PEG) and/or minor fractions of highly ethoxylated PPO polyol. The presence of either polyethylene homopolymer (PEG) and/or minor fractions of highly ethoxylated PPO polyol is commonly attributed to haze and/or solid in the final product, as these more hydrophilic species are not miscible with the major fraction of the product, which consists of a highly hydrophobic PPO polyol.

In the production of polyols for the intended use in polyurethane products, the presence of the difunctional PEG-species can adversely affect the molar ratio of hydroxyl-to-isocyanate during the formation of polyurethane products. Surprisingly, when ethoxylated hydrophobic aliphatic alcohols, the amount of haze in the final product is relatively minimal (as compared to the KOH- catalyzed versions of the same product). The reduction of the haze in the DMC-catalyzed fatty alcohol ethoxylates is depicted by the relatively low levels of PEG in the final product (see Table 1). This aspect of low haze/PEG is surprising, as it contradicts the notion that DMC preferentially ethoxylates at the most hydrophilic site.

Lastly, alcohol ethoxylates that have been prepared using initiators such as nonanol, decanol (and branched-isomers thereof), undecanol (and branched-isomers thereof), dodecanol, tridecanol (and branched-isomers thereof), tetradecanol, pentadecanol, hexadecanol, octadecanol (and branched-isomers thereof), 2-propyl-heptanol, 2-ethyl-hexanol and castor oil appear to have lower amounts of residual water when catalyzed with a DMC catalyst. This is most likely a consequence of either (i) no water in the initial loading of the catalyst into the alcohol feedstock or (ii) no need to neutralize the final product in the system, which can produce small amounts of residual water in the alcohol ethoxylate feedstock.

As compared to alkoxylates that are synthesized using alkaline catalysts (e.g. potassium hydroxide and sodium hydroxide), alkoxylates prepared using DMC have lower amounts of water, PEG and HEmAA. Having lower quantities of both PEG and HEmAA can greatly reduce the formation of 1 ,4-dioxane during the sulfation of alkoxylates. Sulfation of an alcohol ethoxylate is a common practice to increase the detergency properties of the polyether and increase its calcium tolerance during dissolution. Sulfation of alkoxylates, in particular ethoxylates, is obtained in subsequent reaction, where the alkoxylate’s hydroxyl terminus is converted to the sulfonic acid (or salt thereof when neutralized). A common sulfate salt of an alkoxylate includes sodium lauryl n-ether sulfate, where the number of moles of the ether substrate is controlled during the preparation of the alkoxylate (number of ethylene oxide moles, n). In the case where n=0 (i.e. the unreacted/free alcohol), the properties are substantially different as compared to alkoxylates with n > 0. Higher quantities of unreacted/free alcohol can adversely affect the properties of the alkyl-ether sulfate. For instance, detergency and ease of handling of the resulting sulfated-ethoxylate are both minimized by the increased presence of the unreacted/free alcohol in the alcohol ethoxylate feedstock.

Alkoxylates are commonly industrially sulfated in a thin film sulfation unit (such as manufactured by Ballestra or Chemithon) or by other sulfation manufacturing routes, for instance using chlorosulfation or sulfamic acid. There are several factors that lead to the formation of 1 ,4-dioxane during the production of alkyl ether sulfates, including the type of equipment used, the reaction conditions and quality of the alkyl ethoxylate feedstock. The equipment varies on the style and volume used to produce the sulfated material, placing the burden of production on the engineering. The reaction conditions have demonstrated several key criteria that correlate the formation of 1 ,4-dioxane during the sulfation process. For instance, when using air/SC>3 sulfonation process, the molar ratio of SQrto-feedstock must remain at 1 .03 to keep the formation of 1 ,4-dioxane at relatively low levels (< 30 ppm). Above this critical molar level, the formation of 1 ,4-dioxane increases dramatically.

Other means to reduce the formation of 1 ,4-dioxane during the sulfation process of alkyl ethoxylates is to alter the feedstock of the alkyl ethoxylate itself. Sulfation of the DMC-catalyzed material results in less 1 ,4-dioxane due to the reduced amount of water, PEG and HEmAA that is present in the DMC-catalyzed material. Surprisingly, using the DMC catalyst during the alkoxylation, especially ethoxylation, process produces lower PEG content as compared to ethoxylates prepared by traditional alkaline catalysis (i.e. potassium hydroxide). Additionally, the DMC catalysis gives a narrow polydispersity as compared to traditional catalysts like potassium hydroxide or sodium hydroxide. This narrow dispersion can help to reduce the amount of the higher EO-mol ethoxylate species, resulting in less dioxane formation as well as 1 ,4-dioxane can only form when the excess S03 _(g > can react with ethoxylates that have n > 2.

In one embodiment, the present subject matter relates to a process comprising: a) reacting an alcohol ROH, where R is a Ce-22 linear and/or branched alkyl with n moles of ethylene oxide, where n ranges from 1 to 20, using a double metal cyanide catalyst to form an ethoxylated mixture comprising an ethoxylate having the formula R-(OCH CH ) _n -OH, high EO-mole alkoxylates (HEmAA), PEG in an amount equal to or less than 0.5 wt%, and water at a level of less than 0.1 wt%, based on the total weight of the ethoxylated mixture, the ethoxylated mixture having a polydispersity less than 1 .20, wherein the HEmAA is present at a level in the ethoxylated mixture that is at least 25% lower than an ethoxylated mixture produced with a KOH catalyst under identical conditions; and b) sulfating the ethoxylated mixture to form a sulfated mixture comprising a sulfated alkoxylate, a sulfated PEG and 1 ,4-dioxane, wherein the 1 ,4-dioxane level prior to vacuum stripping in the sulfated mixture is at least 25% less than the 1 ,4-dioxane that is generated using an ethoxylate that was prepared using the KOH catalyst, under the identical conditions of step a). Preferably, the polydispersity of the ethoxylated mixture is less than 1.15. More preferably, the polydispersity of the ethoxylated mixture is less than 1 .10.

Preferably, the the double metal cyanide catalyst is a tert-butyl alcohol complexed double metal cyanide catalyst. Preferably, the 1 ,4-dioxane level in the sulfated mixture is reduced by at least 30% as compared to the sulfated mixture prepared by the KOH catalyst. More preferably, the 1 ,4-dioxane level in the sulfated mixture is reduced by at least 33% as compared to the sulfated mixture prepared by the KOH catalyst. Even more preferably, the 1 ,4-dioxane level in the sulfated mixture is reduced by at least 35% as compared to the sulfated mixture prepared by the KOH catalyst.

Preferably, the alcohol ROH is selected from hexanol, octanol, nonanol, decanol and branched- isomers thereof, undecanol and branched-isomers thereof, dodecanol, lauryl alcohol, tridecanol and branched-isomers thereof, C11-C14 C13 rich alcohol such as EXXAL 13 from Exxon Mobil, tetradecanol, pentadecanol, hexadecanol, octadecanol and branched-isomers thereof, behenyl alcohol, 2-propyl-1 -heptanol, 2-ethyl-hexanol, isotridecyl alcohol, C9-C11 alcohol such as NEODOL 91 from Shell Chemical, C12-C13 alcohol such as NEODOL 23 from Shell Chemical, C12- C15 alcohol such as NEODOL 25 from Shell Chemical, 2-butyl-1 -octanol, 2-hexyl-1 -decanol, mid- branched C12-13 alcohol such as SAFOL 23 from Sasol Ltd., or mixtures thereof.

Preferably, the level of HEmAA in the ethoxylated mixture is at least 45% lower than the ethoxylated mixture produced with the KOH catalyst under identical conditions.

Preferably, the sulfation process of step b is selected from thin film sulfation, chlorosulfation or sulfation with sulfamic acid. Preferably, R is a C10-C16 linear and/or branched alcohol. Preferably, R is a C12-C16 linear alkyl. Preferably, n ranges from 1 to 10. Preferably, n is 1 (for Laureth-1) or n is 2 for Laureth-2) or n is 3 (for Laureth-3) or n is 7 (for Laureth-7).

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 represents a distribution of Laureth-2 prepared via KOH and DMC, reported as the percent composition (area percent of each ethoxymer from GC-FID chromatogram). There are lower amounts of HEmAA in the DMC-catalyzed version of the lauryl ethoxylate.

Figure 2 represents a distribution of Laureth-3 prepared via KOH and DMC, reported as the percent composition (area percent of each ethoxymer from GC-FID chromatogram). There are lower amounts of HEmAA in the DMC-catalyzed version of the lauryl ethoxylate.

Figure 3 represents a distribution of Laureth-7 prepared via KOH and DMC, reported as the percent composition (area percent of each ethoxymer from GC-FID chromatogram). There are lower amounts of HEmAA in the DMC-catalyzed version of the lauryl ethoxylate.

Figure 4 represents a distribution of C9-C11 Pareth-5 prepared via KOH and DMC, reported as the percent composition (area percent of each ethoxymer from GC-FID chromatogram). There are lower amounts of HEmAA in the DMC-catalyzed version of the C9-C11 alcohol ethoxylate.

Figure 5 represents a distribution of C9-C11 Pareth-6 prepared via KOH and DMC, reported as the percent composition (area percent of each ethoxymer from GC-FID chromatogram). There are lower amounts of HEmAA in the DMC-catalyzed version of the C9-C11 alcohol ethoxylate.

EXAMPLES

The examples below are illustrative of a two-step process in which during the first step (Step-A) the initiator molecule, which contains a free active hydrogen (for instance a linear or branched primary or secondary alcohol), is ethoxylated with a controlled amount of ethylene oxide, using either potassium hydroxide (KOH) or tert-butyl alcohol complexed-double metal cyanide (DMC) catalytic systems. The second step (Step-B) consists of sulfation of the ethoxylated product using first chlorosulfonic acid to prepare the hydrogen alkyl sulfate and secondly sodium hydroxide to neutralize the acid and cease the sulfation reaction. These samples were then tested for 1 ,4- dioxane that was produced during the formation of the hydrogen alkyl sulfate.

EXAMPLE 1 -KOH

STEP-A: Lauryl alcohol (202 parts) and a 50% aqueous solution (w/w) of potassium hydroxide (1 part) were added into a 3.5 L Anton Parr reactor vessel. The solution was heated to 110°C and a vacuum was applied for one hour to remove the excess water from the solution. Once dewatered, a nitrogen header was applied, and the temperature was raised to 155°C while stirring. At this temperature, a small amount of ethylene oxide (21 parts) was added. After a drop in the reactor pressure was observed, the remainder of the ethylene oxide (EO) was added via continuous addition until all the EO (92 parts in total) was consumed. After which, the sample was cooled to 110°C, where it was deodorized via vacuum stripping and nitrogen purge. The final stage included lowering the temperature to 70°C and adjusting the pH of the final product to 6-8 using acetic acid. Typical characterization of the ethoxylate included determination of the hydroxyl-value (OH-value), the amount of free-alcohol present in the final product as well the determination of the amount polyethylene-glycol (PEG) that was produced during the ethoxylation (see Table 1 and Table 2).

Table 1. Comparison of the properties of various alcohol ethoxylates prepared by KOH and DMC.

Example No. & ID Catalyst ^* OH-Value (mgKOH/g) Water Content (wt %) PEG (wt%)

KOH 197.4 0.11 0.3

(1) Laureth-2

DMC 197.1 0.27 0.2

KOH 172.8 0.14 0.7

(2) Laureth-3

DMC 172.1 0.09 0.4

KOH 114.1 0.67 5.1

(3) Laureth-7

DMC 114.0 0.26 0.5

KOH 142.9 0.27 2.1

(4) C9-C11 Pareth-5

DMC 143.0 0.17 0.3

KOH 129.4 0.12 0.9

(5) C9-C11 Pareth-6

DMC 132.7 0.11 0.2

Table 2. Free Alcohol, PDI and HEmAA of various alcohol ethoxylates prepared by KOH and PMC

Example No. & ID Catalyst Free Alcohol (wt%) M _w /M _n (PDI) HEmAA

KOH 21 1.097 8%

(1) Laureth-2

DMC 16 1.070 3%

KOH 14 1.110 9%

(2) Laureth-3

DMC 6 1 .070 4%

KOH 2.1 1.133 9%

(3) Laureth-7

DMC 0.4 1 .047 4%

KOH 3.7 1.184 16%

(4) C9-C11 Pareth-5

DMC 0.7 1 .062 5%

KOH 2.8 1.173 17%

(5) C9-C11 Pareth-6

DMC 0.4 1 .051 7%

STEP-B: To the ethoxylate from EXAMPLE-1 -KOH (5.3 parts), chlorosulfonic acid (2.3 parts) was added dropwise under nitrogen. The reaction stirred and kept under 45oC via slow addition of the chlorosulfonic acid. The total addition time of the chlorosulfonic acid was held constant at 20 minutes, after which, the solution was allowed to stir for an additional five minutes as the reaction cooled. The pH of the system was raised to alkalinity using a 50% solution of sodium hydroxide (1 part). After addition of the sodium hydroxide solution, samples were kept in a freezer until analysis for 1 ,4-dioxane using GC/FID. Typical characterization of the sulfated ethoxylate included determination of the residual 1 ,4-dioxane present in the product (see Table 3).

Table 3. Content of 1,4-Dioxane in Sulfated Ethoxylates

Example No. & ID Catalyst Cat. Loading (ppm) 1,4-Dioxane (ppm)

KOH 1046 56

KOH 3388 51

(1) Laureth-2

DMC 40 34

DMC 80 36

EXAMPLES 2-3-KOH

STEP-A: The procedure to synthesize all other KOH-catalyzed comparative ethoxylates is considered to be the same as EXAMPLE 1-KOH. In each example, the amount of KOH catalyst (1 part) remains the same, while the amounts of lauryl alcohol and of EO is systematically varied to produce the corresponding ethoxymer. Typical characterization of the ethoxylate included determination of the hydroxyl-value (OH-value), the amount of free-alcohol present in the final product as well the determination of the amount polyethylene-glycol (PEG) that was produced during the ethoxylation (see Table 1 and Table 2).

EXAMPLE 1 -DMC

STEP-A: The catalyst, Product name “DMC Catalyst”, commercially available from Huaian Bud Polyurethane Science & Technology Co., Ltd., (1 part) was dispersed in a small amount of lauryl alcohol, which was then added to an Anton Parr reactor that contained lauryl alcohol (20374 parts in total). The solution was heated to 110°C and a vacuum was applied for one hour to remove the excess water from the solution. Once dewatered, a nitrogen header was applied, and the temperature was raised to 140°C while stirring. At this temperature, ethylene oxide (2144 parts) was added. After a sudden drop in the reactor pressure was observed, the remainder of the ethylene oxide (EO) was added via continuous addition until all the EO (4326 parts) was rapidly consumed. After which, the sample was cooled to 110°C, where it was deodorized via vacuum stripping and nitrogen purge. Typical characterization of the ethoxylate included determination of the hydroxyl-value (OH-value), the amount of free-alcohol present in the final product as well the determination of the amount polyethylene-glycol (PEG) that was produced during the ethoxylation (see Table 1 and Table 2).

STEP-B: To the ethoxylate from EXAMPLE 1 -DMC (5.3 parts), chlorosulfonic acid (2.3 parts) was added dropwise under nitrogen. The reaction stirred and kept under 45°C via slow addition of the chlorosulfonic acid. The total addition time of the chlorosulfonic acid was held constant at 20 minutes, after which, the solution was allowed to stir for an additional five minutes as the reaction cooled. The pH of the system was raised to alkalinity using a 50% solution of sodium hydroxide (1 part). After addition of the sodium hydroxide solution, samples were kept in a freezer until analysis for 1 ,4-dioxane using GC/FID. Typical characterization of the sulfated ethoxylate included determination of the residual 1 ,4-dioxane present in the product (see Table 3).

EXAMPLES 2-3-DMC

STEP-A: The procedure to synthesize all other DMC-catalyzed comparative ethoxylates is considered to be the same as EXAMPLE 1 -DMC. In each example, the amount of the catalyst, product name “DMC Catalyst”, commercially available from Huaian Bud Polyurethane Science & Technology Co., Ltd., (1 part) remains the same, while the amounts of lauryl alcohol and of EO is systematically varied to produce the corresponding ethoxymer. Typical characterization of the ethoxylate included determination of the hydroxyl-value (OH-value), the amount of free-alcohol present in the final product as well the determination of the amount polyethylene-glycol (PEG) that was produced during the ethoxylation (see Table 1 and Table 2).

EXAMPLE 4 -KOH

STEP-A: C9-C11 alcohol, also referred to as Neodol-91 , (211 parts) and a 50% aqueous solution (w/w) of potassium hydroxide (1 part) were added into a 3.5 L Anton Parr reactor vessel. The solution was heated to 110°C and a vacuum was applied for one hour to remove the excess water from the solution. Once dewatered, a nitrogen header was applied, and the temperature was raised to 155°C while stirring. At this temperature, a small amount of ethylene oxide (22 parts) was added. After a drop in the reactor pressure was observed, the remainder of the ethylene oxide (EO) was added via continuous addition until all the EO (289 parts in total) was consumed. After which, the sample was cooled to 110°C, where it was deodorized via vacuum stripping and nitrogen purge. The final stage included lowering the temperature to 70°C and adjusting the pH of the final product to 6-8 using acetic acid. Typical characterization of the ethoxylate included determination of the hydroxyl-value (OH-value), the amount of free-alcohol present in the final product as well the determination of the amount polyethylene-glycol (PEG) that was produced during the ethoxylation (see Table 1 and Table 2).

EXAMPLE 4-DMC

STEP-A: The catalyst, Product name “DMC Catalyst”, commercially available from Huaian Bud Polyurethane Science & Technology Co., Ltd., (1 part) was dispersed in a small amount of C9- C11 alcohol, which was then added to an Anton Parr reactor that contained C9-C11 alcohol (10556 parts in total). The solution was heated to 110°C and a vacuum was applied for one hour to remove the excess water from the solution. Once dewatered, a nitrogen header was applied, and the temperature was raised to 140°C while stirring. At this temperature, ethylene oxide (1111 parts) was added. After a sudden drop in the reactor pressure was observed, the remainder of the ethylene oxide (EO) was added via continuous addition until all the EO (14444 parts) was rapidly consumed. After which, the sample was cooled to 110°C, where it was deodorized via vacuum stripping and nitrogen purge. Typical characterization of the ethoxylate included determination of the hydroxyl-value (OH-value), the amount of free-alcohol present in the final product as well the determination of the amount polyethylene-glycol (PEG) that was produced during the ethoxylation (see Table 1 and Table 2).

EXAMPLE 5 -KOH

STEP-A: C9-C11 alcohol, also referred to as Neodol-91 , (189 parts) and a 50% aqueous solution (w/w) of potassium hydroxide (1 part) were added into a 3.5 L Anton Parr reactor vessel. The solution was heated to 110°C and a vacuum was applied for one hour to remove the excess water from the solution. Once dewatered, a nitrogen header was applied, and the temperature was raised to 155°C while stirring. At this temperature, a small amount of ethylene oxide (20 parts) was added. After a drop in the reactor pressure was observed, the remainder of the ethylene oxide (EO) was added via continuous addition until all the EO (311 parts in total) was consumed. After which, the sample was cooled to 110°C, where it was deodorized via vacuum stripping and nitrogen purge. The final stage included lowering the temperature to 70°C and adjusting the pH of the final product to 6-8 using acetic acid. Typical characterization of the ethoxylate included determination of the hydroxyl-value (OH-value), the amount of free-alcohol present in the final product as well the determination of the amount polyethylene-glycol (PEG) that was produced during the ethoxylation (see Table 1 and Table 2).

EXAMPLE 5-DMC

STEP-A: The catalyst, Product name “DMC Catalyst”, commercially available from Huaian Bud Polyurethane Science & Technology Co., Ltd., (1 part) was dispersed in a small amount of C9- C11 alcohol, which was then added to an Anton Parr reactor that contained C9-C11 alcohol (9463 parts in total). The solution was heated to 110°C and a vacuum was applied for one hour to remove the excess water from the solution. Once dewatered, a nitrogen header was applied, and the temperature was raised to 140°C while stirring. At this temperature, a small amount of ethylene oxide (996 parts) was added. After a sudden drop in the reactor pressure was observed, the remainder of the ethylene oxide (EO) was added via continuous addition until all the EO (15537 parts) was rapidly consumed. After which, the sample was cooled to 110°C, where it was deodorized via vacuum stripping and nitrogen purge. Typical characterization of the ethoxylate included determination of the hydroxyl-value (OH-value), the amount of free-alcohol present in the final product as well the determination of the amount polyethylene-glycol (PEG) that was produced during the ethoxylation (see Table 1 and Table 2). Hydroxyl Value (OH-Value) Test: Hydroxyl analysis is performed by esterification with Acetic Anhydride in Pyridine of the hydroxyl group and follows ASTM E222. Dependent upon the expected hydroxyl value, sample is weighed into a reflux flask and 5ml_ of the acetic anhydride and pyridine solution (1 :3) is added into the sample flask as into a blank and they are refluxed for 30 minutes. Samples are allowed to cool and are titrated with 0.5 M KOH in methanol until the end point is reached. Results are expressed in mgKOH/g.

Test for Determination of the Weight Percent of Polyethylene Glycol (PEG): Using an Agilent Infinity II series High Performance Liquid Chromatography (HPLC) instrument with an Evaporative Light Scattering Detector (ELSD) the percent Polyethylene glycol (PEG) is determined. Separation is carried out using a C18250mm x4.6mm x 5um column with a gradient mobile phase described below. The ELSD conditions are as follows: Evaporator 60°C, Nebulizer 60°C and gas flow N2 1 mL/min. Standards were prepared by diluting PEG 400 in methanol to concentrations of 0.1 to 3.5% for a 1 g sample in a 10mL volumetric flask. In a 10mL volumetric flask, 1 g of sample is used and is diluted in methanol and filled to the mark. All analysis was carried out using Agilent ChemStation software.

Table 4. Mobile phase conditions for PEG separation

Test to Determine the Weight Percent of Free Fatty Alcohol and Distribution of Ethoxymers: Free alcohol percent is determined using an Agilent 7890 Gas Chromatography with a Flame Ionization Detection (GCFID) and a Quadrex 50 HT (50% Phenyl Methylsiloxane) column, 25m x 0.25mm 0, film thickness of 0.1 pm. All gas and column conditions are listed below for liquid injection. Standard samples are prepared from either the raw material (i.e. 2PH and NEODOL 91) or individual alcohol chains in the case for lauryl alcohol ethoxylates. Bis-Trimethyl Silyltrifluoroacetamide (BSTFA) is added to both the standard and the unknown samples to produce silyl derivatives by esterification. An internal standard of non-overlapping retention is additionally added to both standard and unknown samples to determine the final non-ethoxylated free alcohol content. The oligomer distribution is derived from the area percentage calculation. Table 5. Conditions for GC/FID

Test to Determine the Amount of Residual Water in the Sample: The amount of water/moisture in the samples were determined via Karl Fisher titration, in which a known amount of sample is added to the titrant, and the amount of water present in the sample is calculated based on the concentration of iodine in the Karl Fisher titrating reagent (i.e., titer) and the amount of Karl Fisher Reagent consumed in the titration. The amount of water/moisture in the final product is recorded as a percentage of the entire mass (wt %).

Test to Determine the Amount of 1,4-Dioxane in the Sample: Agilent 7890 GCFID with DB-1 - 123-1064 of 60m x 0.32mm x 3.0pm capillary column is used for the determination of EO and dioxane by headspace injection. GCFID conditions are listed below. The standards are made by diluting ethylene oxide 50 mg/ml in methylene chloride in octanol and 1 ,4-dioxane 2000 ug/ml in methanol in octanol, adding to headspace vial of 0.5-5 ppm or higher of each component with a total mass of 10g where calculations are based on a 5g sample scale. The samples are prepared by weighing 5g of octanol and 5g of the sample into a headspace vial. Chromatograms are analyzed using Agilent Chemstation software.

Table 6. Analysis conditions of the gas chromatograph to determine 1,4-dioxane