JPH024762A - Production of alkyl ether sulfate - Google Patents

Abstract

PURPOSE:To obtain the subject compound having improved color and odor and useful as a base for shampoo, etc., by sulfating a specific polyoxyethylene alkyl ether. CONSTITUTION:The objective alkyl ether sulfate is produced by sulfating a polyoxyethylene alkyl ether having an average molar number of added ethylene oxide of 2-4 and containing <=20wt.% of component having a molar number of added ethylene oxide of <=1. The total amount of the components having a molar number of added ethylene oxide of >=5 is <=30wt.% and especially preferably the total amount of the components having an added molar number of average value + or -1 is >=60wt.%. The sulfation is performed with a mixed gas produced by diluting sulfur trioxide with an inert gas or by using chlorosulfonic acid.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing an alkyl ether sulfate.

Specifically, the present invention relates to a method for producing an alkyl ether sulfate having improved hue and odor. The alkyl ether sulfate obtained by the method of the present invention can be directly incorporated into detergent compositions as a base material for shampoos, body shampoos, and dishwashing detergents without the need for decolorization or deodorization.

[Conventional technology]

Conventionally, liquid detergents for shampoos, face washes, dishes, and clothing have been formulated with linear alkylbenzene sulfonates, alkyl sulfate ester salts, alkyl ether sulfates, etc. as base materials, but these have not come in direct contact with the skin of hands. Alkyl ether sulfates are widely used in shampoos for washing, detergents for hand-washing dishes, etc. due to their gentleness on the skin.

However, when producing alkyl ether sulfates, when ordinary polyoxyethylene alkyl ether is sulfated with gaseous SOI or chlorosulfonic acid, the reaction is violent and side reactions such as dehydration and carbonization occur. This may result in yellow coloration or a strange odor, requiring decolorization with hydrogen peroxide or the addition of specific fragrances.

Furthermore, JP-A No. 57-16097 discloses a method of removing relatively low-boiling substances that are thought to be the cause of odors by subjecting sulfates to reduced pressure, but since sulfates have a high viscosity, However, it is difficult to apply it to continuous manufacturing methods.

[Problem to be solved by the invention]

The present invention provides a method for producing a substantially colorless, transparent and odorless alkyl ether sulfate, which allows it to be incorporated into cleaning agents as it is after sulfation and subsequent neutralization without undergoing operations such as decolorization and deodorization. This is what we intend to provide.

[Means to solve the problem]

As a result of various studies, the present inventors found that instead of ordinary polyoxyethylene alkyl ether, which has a wide distribution of added moles of ethylene oxide, polyoxyethylene alkyl ether has a narrow addition distribution of ethylene oxide and has less unreacted alcohol. It has been found that the above-mentioned problems can be solved by using and sulfating this.

That is, the present invention provides a method for producing an alkyl ether sulfate by sulfating polyoxyethylene alkyl ether with a sulfating agent such as gaseous S03 or chlorosulfonic acid, in which the polyoxyethylene alkyl ether has an average added mole of ethylene oxide. The number (p) is in the range of 2 to 4, and the component with an added mole of ethylene oxide of 1 or less is 20% by weight or less, and the component with an added mole of ethylene oxide of 5 or more is 30% by weight.
The present invention provides a method for producing an alkyl ether sulfate with improved hue and odor, characterized by using polyoxyethylene alkyl ether having a weight of 4% or less.

Polyoxyethylene alkyl ether is obtained by adding ethylene oxide to higher alcohol to -C. Specific examples of higher alcohols include natural alcohols and synthetic alcohols such as oxo alcohols and Ziegler alcohols. Further, the carbon number of the higher alcohol is selected within the range of 7 to 21, but preferably 11 to 15.

The average value p of the number of added moles p of ethylene oxide in the polyoxyethylene alkyl ether used in the present invention is selected in the range of 2 to 4, the sum of the components in which p is 1 or less is 20% by weight or less, and p is The sum of 5 or more components is 30% by weight or less. Further, it is particularly preferable that the sum of the components in the range of 7±1 is 60% by weight or more. If the sum of components with p of 1 or less exceeds 20% by weight, the hue will deteriorate significantly during sulfation. In particular, if unreacted alcohol corresponding to p = o among components with p of 1 or less exceeds 10% by weight, the hue deteriorates markedly and the color of a 10% by weight aqueous solution of alkyl ether sulfate becomes a crette color (1
The value obtained by multiplying the absorbance at 420 nm in the 0 Tsuru cell by 1000) is 50 or more, giving it a yellow color. As the amount of highly adducted molar forms of ethylene oxide increases, the odor that is thought to be due to peroxides and cyclic ethers produced as by-products during sulfation becomes noticeable, and especially when the p-s or higher component exceeds a 30-star shape, a sour taste becomes noticeable. The fishy odor becomes noticeable.

The polyoxyethylene alkyl ether used in the present invention is generally a polyoxyethylene alkyl ether with a wide ethylene oxide addition molar distribution obtained by adding ethylene oxide to a higher alcohol using an alkali metal catalyst, or an alkaline earth metal catalyst. It is obtained by distillation or extraction of polyoxyethylene alkyl ether, which is obtained by adding ethylene oxide to a higher alcohol using an acid catalyst and has a narrow distribution of added moles.

The sulfation method uses a falling film sulfation device.
At a temperature of 30°C, 1.05 to 1.10 times the molar amount of chlorosulfonic acid was added dropwise to 1.02 to 1.10 molar amount of chlorosulfonic acid per 1 mole of polyoxyethylene alkyl ether. Examples include a method in which the reaction is carried out at a temperature of 0.degree. C. or lower.

Furthermore, an aqueous solution of an alkali metal or triethanolamine is used to neutralize sulfates.

Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

[Example] Polyoxyethylene alkyl ether (p = 3) obtained by adding 3 moles of ethylene oxide to a higher alcohol having 12 to 13 carbon atoms (Dopanol 23 manufactured by Mitsubishi Yuka) was added to 1
Table 1 obtained by vacuum distillation under high vacuum of 11 g or less
Using polyoxyethylene alkyl ether having the distribution of added moles of ethylene oxide shown in 1.05 times mole) at a temperature of 30°C. The product was neutralized with an aqueous sodium hydroxide solution to obtain an alkyl ether sulfate. Table 1 shows the evaluation results of the odor and hue of this alkyl ether sulfate.

[Comparative Example 1] Polyoxyethylene alkyl ether having the distribution shown in Table 1 obtained by topping a low boiling point component containing unreacted alcohol in the same manner as in the example was used. The color and odor of the sulfate were evaluated, and the results are shown in Table 1.

[Comparative Example 2] Using the same polyoxyethylene alkyl ether that was subjected to vacuum distillation in the example, it was sulfated in the same manner as in the example, and the hue and odor of the sulfate were evaluated. The results are shown in Table 1. Indicated.

Table 1

Claims (1)

[Claims] In a method for producing an alkyl ether sulfate by sulfating polyoxyethylene alkyl ether, the average number of added moles of ethylene oxide (@p@) is in the range of 2 to 4, and the polyoxyethylene alkyl ether has an added mole of ethylene oxide. Components of number 1 or less are 20% by weight or less,
A method for producing an alkyl ether sulfate, characterized in that a polyoxyethylene alkyl ether in which a component having an added mole of ethylene oxide of 5 or more is 30% by weight or less is used.