JPH04120090A - Production of alkyl glycoside - Google Patents

Abstract

PURPOSE:To profitably produce the subject compound having a pale color and useful as a raw material for cleansers by reacting a saccharide with an alcohol in the presence of an acid and neutralizing the acid catalyst in the reaction product with an alkaline earth metal hydroxide. CONSTITUTION:A saccharide is reacted with a 8-18C alcohol (preferably 10-14C alcohol) preferably in a molar ratio of 1:1 to 10:1 in the presence of an acid catalyst such as hydrochloric acid preferably in an amount of 5 to 30 milli equivalent per mole of the saccharide, while the produced water is removed outside. The acid catalyst in the reaction product is neutralized with an alkaline earth metal hydroxide (preferably magnesium hydroxide) and the excessive alcohol is removed to provide the objective compound.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing light-colored alkyl glycosides.

Alkyl glycosides have surface activity and are useful as raw materials for cleaning agents.

[Conventional technology]

Methods for producing alkyl glycosides include a method in which sugar and alcohol are directly reacted, and a method in which a lower alkyl glycoside obtained by reacting sugar and a lower alcohol such as butanol is acetal exchanged with a higher alcohol (E
P-132046, JP-A-64-47796, etc.) are representative.

The direct reaction method has lower equipment costs and other costs than the acetal exchange method, but it is difficult to control the reaction.
Reaction products tend to be colored.

As a method for obtaining a light-colored alkyl glyconde by direct reaction, the acid catalyst is selected from the group consisting of phosphorous acid, hypophosphorous acid, sulfurous acid, hyposulfite, nitrous acid, and/or hyponitrous acid or salts thereof. A method in which the aqueous alkyl polyglycoside solution obtained by the reaction is first bleached with a hydrogen peroxide solution and then treated with a sulfur dioxide source (Japanese Patent Laid-Open No. 59139397) 6133193) and the like are known.

Further, in European Patent No. 0132046, as a neutralizing agent for an acid catalyst, the following formula (I) (R"○)n'M (I) (wherein R' is an alkyl group having 1 to 30 carbon atoms) is used. or an acyl group, M is an alkali metal, alkaline earth metal, or aluminum, and n'' is 1 when M is an alkali metal, 2 when M is an alkaline earth metal, and 3 when M is aluminum. A method using an organic base represented by (a) is disclosed.

PROBLEMS TO BE SOLVED BY THE INVENTION It is an object of the present invention to provide a method for producing alkyl glycosides that do not require complicated steps or expensive reagents and are sufficiently light in color to be used as detergents.

[Means to solve the problem]

The present invention is a method for producing an alkyl glycoside by reacting sugar and alcohol in the presence of an acid catalyst and neutralizing the acid catalyst in the resulting reaction product with an alkaline earth metal hydroxide.

As the sugar, not only monosaccharides derived from starch but also trisaccharides and trisaccharides can be used.

Specific examples of monosaccharides include hexoses such as glucose, mannos, galactose, sucrose, fructose, sorbose, tagalose, and buncose, and pentoses such as arabinose, xylose, ribose, lyxose, ribulose, and xylulose. Among these, glucose is preferred because of its availability and low cost.

As the alcohol, a linear or branched primary alcohol having 8 to 18 carbon atoms is used.

Specifically, octyl alcohol, nonyl alcohol,
Decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, heptadecyl alcohol, octadecyl alcohol (
stearyl alcohol) or a mixture thereof. Among these, alcohols having 10 to 14 carbon atoms are preferred.

The ratio of sugar and alcohol is sugar:alcohol-1:1~2
0:L is preferably in the range of 1:1 to 10:1 (molar ratio).

Acid catalysts used in the process of the invention include strong mineral acids such as hydrochloric acid, hydrofluoric acid, phosphoric acid, sulfuric acid, and mixtures thereof; strong mineral acids such as phosphonic or sulfonic acids of alkyl, alkylaryl or aryl compounds; Examples include organic acids. Representative examples of strong organic acids include sulfonic or phosphonic acids having methyl, ethyl, butyl, propyl or amyl groups, phenylsulfonic acid, phenylphosphonic acid,
Mention may be made of para-toluenesulfonic acid, para-toluenephosphonic acid and mixtures thereof.

The amount of acid catalyst used is 1 to 100 milliliters per mole of sugar.
Preferably, it is in the range of 5 to 30 milliequivalents. If the amount of acid catalyst is too small, the reaction rate will be slow, and if it is too large, the resulting aqueous alkyl glycoside solution will tend to become cloudy.

The method of the present invention involves directly reacting sugar and Cs-+e alcohol in the presence of an acid catalyst.

The reaction between sugar and 08-□8 alcohol is generally 100~
The process is carried out at a temperature of 200°C and proceeds by removing the water produced from the system.

Removal of water from the reaction system results in Ca-+
a) Remove water from the system by vacuuming at a pressure that does not substantially evaporate the alcohol.

After the reaction is completed, the acid catalyst in the reaction product is neutralized.

In the present invention, examples of the alkaline earth hydroxide used as a neutralizing agent for the acid catalyst include magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, and the like. Among these, it is preferable to use magnesium hydroxide because it has the best decolorizing effect.

The amount of alkaline earth metal hydroxide used is in the range of 1 to 2 equivalents, preferably 1.1 to 1.6 equivalents, based on the acid catalyst. If the amount of alkaline earth metal hydroxide used is small,
If the neutralization is not complete or too much, the aqueous alkyl glycoside solution will become cloudy.

Although the neutralization temperature ranges from room temperature to the glycosidation reaction temperature, a high temperature is preferable in order to complete neutralization reliably in a short time, and a range of 90° C. to the glycosidation reaction temperature is preferable.

The time required for neutralization varies depending on the amount of neutralizing agent, temperature, efficiency of the stirring device, etc., but is generally in the range of 10 to 60 minutes.

After neutralization, excess alcohol can be removed by vacuum distillation or the like to obtain the desired alkyl glycode.

The alkyl glycoside obtained by the method of the present invention is
Indicated below - Sailor.

RO[X],,H (In the formula, R is an alkyl group having 8 to 18 carbon atoms, X is a pentose or hexose, and n represents an integer of 1 to 20.) Effect] By the method of the present invention, a light-colored alkyl glycoside suitable as a detergent can be industrially advantageously produced.

〔Example〕

The present invention will be explained in more detail with reference to Examples below.

The higher alcohol used in the following experiments was obtained by hydroformylating an alpha olefin with a carbon number of 11.
It is a so-called oxo alcohol with a linear chain ratio of 72%.

<Example 1> 1500 g (8.72 mol) of C11 higher alcohol was charged into a 51 flask equipped with a stirrer, a thermometer, and a dropping funnel, and 5 g of para-toluenesulfonic acid monohydrate (
26.3 meq) was added.

Place the flask in an oil bath adjusted to 125°C, and add 75 g (0.42 mol) of anhydrous glucose from the dropping funnel.
was added and stirred.

The pressure of the flask was reduced to about 100 Torr to remove by-product water from the system.

When the reaction solution became clear, 75 g of anhydrous glucose was added from the dropping funnel, and the same operation was continued until the total amount of anhydrous glucose added was 300 g (1.67 mol).

Of the 1765 g of crude reaction liquid obtained in this way, 1/10
(176,5g) with a stirrer and thermometer 0,5!
Add 0.0% magnesium hydroxide to the flask as a neutralizing agent.
092 g (3.16 milliequivalents) (1.2 times the equivalent of para-toluenesulfonic acid) was added, and the mixture was stirred at 90° C. for 1 hour.

Next, after increasing the oil bath temperature to 150℃, the pressure was increased to 2
The vacuum was reduced to Torr or less and the excess C11 higher alcohol was distilled down to 1 wt% or less. The time required for distillation was 2 hours.

After raising and lowering the oil bath temperature by about 90° C., ion-exchanged water of the same weight as the weight of the alkyl glucoside remaining in the flask was added, stirred and dissolved, and a transparent 50 wt % aqueous solution of alkyl glucoside was taken out from the flask.

The 50 wt % aqueous solution was further diluted 10 times with ion-exchanged water to make a 5 wt % aqueous solution, which was placed in a glass cell with an optical path length of 10 mm to pass light with a wavelength of 420 nm. The absorbance was 0.168.

<Examples 2 to 4> The same procedure as Example 1 was carried out, except that 176.5 g of the crude reaction liquid obtained in Example 1 was separated and calcium hydroxide, strontium hydroxide, and barium hydroxide were used as neutralizing agents. The same operation was performed. Table 1 shows the absorbance of the 5 wt% aqueous solution.

Comparative Examples 1 to 4> 176.5 g of the crude reaction liquid obtained in Example 1 was separated, and lithium hydroxide, sodium hydroxide, potassium hydroxide, and sodium ethylate were added as neutralizing agents. Example 1
The same operation was performed. Table 1 shows the absorbance of 5wt% aqueous solution.
Shown below.

<Example 5> The same operation as in Example 1 was performed except that 2.58 g (26.3 meq.) of 5Dwt% sulfuric acid was used as a catalyst. 5w
The absorbance of the t% aqueous solution was 0.247.

<Examples 6 to 8> Using the reaction crude liquid obtained in Example 5, the same operations as in Examples 2 to 4 were performed. Table 2 shows the absorbance of the 5 wt% aqueous solution.

<Comparative Examples 5 to 7> Using the reaction crude liquid obtained in Example 5, the same operations as in Comparative Examples 1 to 3 were performed. Table 2 shows the absorbance of the 5 wt% aqueous solution.

table para toluenesulfonic acid catalyst table sulfur acid touch Medium

Claims (2)

[Claims] (1) In a method for producing an alkyl glycoside by reacting sugar and C_■_-_1_■alcohol in the presence of an acid catalyst, the acid catalyst in the reaction product is neutralized with an alkaline earth metal hydroxide. A method for producing an alkyl glycoside, characterized by: (2) The manufacturing method according to claim 1, wherein the alkaline earth metal hydroxide is magnesium hydroxide.