Methods for mitigating 1,4-dioxane and 1,4-dioxane precursors in surfactant solutions

Patent metadata

Field	Value
Publication number	US-2025043187-A1
Application number	US-202418920310-A
Country	US
Kind code	A1
Filing date	Oct 18, 2024
Priority date	Apr 20, 2022
Publication date	Feb 6, 2025
Grant date	—

Abstract

A method of mitigating the formation of 1,4-dioxane and precursors of 1,4-dioxane in alkyl ether sulfate surfactants is disclosed. The method involves adding one or more alcohol, hydrotrope or anti-oxidant additives to an aqueous solution of alkyl ether sulfate surfactant having at least two ethylene oxide groups. The alcohol, hydrotrope, or anti-oxidant is added to the alkyl ether sulfate solution in an amount effective to reduce the formation of diethylene glycol monosulfate, a precursor of 1,4-dioxane, and also reduce the formation of 1,4-dioxane.

First claim

What is claimed is:

1 . A method of mitigating the formation of diethylene glycol monosulfate (DEG-MS) in a surfactant comprising the steps of:
(a) providing an alkyl ether sulfate surfactant having two or more ethylene oxide units, wherein the alkyl ether sulfate surfactant is a concentrate comprising from 50 wt % to 85 wt % of alkyl ether sulfate actives and water; (b) adding one or more additives selected from the group consisting of alcohols, hydrotropes, and anti-oxidants to the alkyl ether sulfate actives, in an amount effective to reduce the formation of DEG-MS in the alkyl ether sulfate actives compared to the same alkyl ether sulfate actives but without the addition of additive.

2 . The method of claim 1 , wherein the effective amount of alcohol additive is in the range of 1 wt % to 12 wt %, preferably greater than 1 wt % to 10 wt % and wherein the alcohol additive has a molecular weight of less than 200.

3 . The method of claim 2 , wherein the alcohol additive is one or more of ethanol, isopropyl alcohol, tert-butyl alcohol, propylene glycol, methanol, 1-propanol, 1-butanol, 1,3-butanediol, or hexylene glycol (2-methyl-2,4-pentanediol).

4 . The method of claim 1 , wherein the effective amount of hydrotrope is in the range of 0.1 wt % to 5 wt % and wherein the hydrotrope is one or more of sodium xylene sulfonate, sodium cumene sulfonate, or sodium toluene sulfonate.

5 . The method of claim 1 , wherein the anti-oxidant additive is in the range of 0.1 wt % to 3.0 wt % and wherein the anti-oxidant additive is one or more of tert butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), citrate, Vitamin A, Vitamin C, Vitamin D, or Vitamin E.

6 . The method of claim 1 , wherein the alkyl ether sulfate surfactant has a neutral pH.

7 . The method of claim 1 , wherein the alkyl ether sulfate surfactant has a caustic pH.

8 . The method of claim 1 , wherein the additive also reduces the formation of 1,4-dioxane in the alkyl ether sulfate actives.

9 . The method of claim 1 , wherein the method further comprises diluting the alkyl ether sulfate surfactant in water to form a diluted aqueous solution, wherein the diluted aqueous solution comprises 1 wt % to 25 wt % of the alkyl ether sulfate actives.

10 . An alkyl ether sulfate composition comprising:
(a) from 50 wt % to 85 wt % of alkyl ether sulfate actives, wherein the alkyl ether sulfate comprises two or more ethylene oxide units; (b) one or more additives selected from the group consisting of alcohols, hydrotropes, and anti-oxidants, wherein the one or more additives are in an amount effective to reduce formation of diethylene glycol monosulfate in the alkyl ether sulfate composition compared to the same alkyl ether sulfate composition without the additive; and (c) water to total 100% of the composition.

11 . The composition of claim 10 , wherein the effective amount of alcohol additive is in the range of 1 wt % to 12 wt %, preferably greater than 1 wt % to 10 wt %, and wherein the alcohol additive is one or more of ethanol, isopropyl alcohol, tert-butyl alcohol, propylene glycol, methanol, 1-propanol, 1-butanol, 1,3-butanediol, or hexylene glycol.

12 . The composition of claim 10 , wherein the effective amount of hydrotrope is in the range of 0.1 wt % to 5 wt % and wherein the hydrotrope is one or more of sodium xylene sulfonate, sodium cumene sulfonate, or sodium toluene sulfonate.

13 . The composition of claim 10 , wherein the anti-oxidant additive is in the range of 0.1 wt % to 3.0 wt % and wherein the anti-oxidant additive is one or more of tert butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), citrate, Vitamin A, Vitamin C, Vitamin D, or Vitamin E.

14 . The composition of claim 10 , wherein the additive also reduces the formation of 1,4-dioxane in the alkyl ether sulfate composition.

15 . An alkyl ether sulfate surfactant composition comprising:
(a) from 1 wt % to 25 wt % of alkyl ether sulfate actives, wherein the alkyl ether sulfate surfactant comprises two or more ethylene oxide units; (b) one or more additives selected from the group consisting of alcohols, hydrotropes, and anti-oxidants, wherein the one or more additives are in an amount effective to reduce formation of diethylene glycol monosulfate in the alkyl ether sulfate surfactant composition compared to the same alkyl ether sulfate surfactant composition without the additive; and (c) water to total 100% of the composition.

16 . The composition of claim 15 , wherein the effective amount of alcohol additive is in the range of 1 wt % to 5 wt % and wherein the alcohol additive has a molecular weight of less than 200.

17 . The composition of claim 16 , wherein the alcohol additive is one or more of ethanol, isopropyl alcohol, tert-butyl alcohol, propylene glycol, methanol, 1-propanol, 1-butanol, 1,3-butanediol, or hexylene glycol.

18 . The composition of claim 15 , wherein the effective amount of hydrotrope is in the range of 0.1 wt % to 5 wt % and wherein the hydrotrope is one or more of sodium xylene sulfonate, sodium cumene sulfonate, or sodium toluene sulfonate.

19 . The composition of claim 15 , wherein the effective amount of anti-oxidant additive is in the range of 0.1 wt % to 3.0 wt % and wherein the anti-oxidant additive is one or more of tert butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), citrate, Vitamin A, Vitamin C, Vitamin D, or Vitamin E.

20 . The composition of claim 15 , wherein the additive also reduces formation of 1,4-dioxane in the alkyl ether sulfate surfactant composition.

Assignees

• Stepan Co

Inventors

• Faunce James A
• Murphy Dennis S
• Masters Ronald A
• Cui Lei
• Knox Paul W

Classifications

• C11D3/3418

  Toluene -, xylene -, cumene -, benzene - or naphthalene sulfonates or sulfates · CPC title

• C11D3/2003

  Alcohols; Phenols · CPC title

• C11D3/0084

  Antioxidants; Free-radical scavengers · CPC title

• C09K23/02 Primary

  Alkyl sulfonates or sulfuric acid ester salts derived from monohydric alcohols · CPC title

• C11D1/29 Primary

  Sulfates of polyoxyalkylene ethers · CPC title