JPH037299A - Production of alkyl glycoside having stable color tone and odor - Google Patents

Abstract

PURPOSE:To obtain the subject glycoside having excellent color, odor and their stability and keeping the color and odor over a long period by decoloring an alkyl glycoside with hydrogen peroxide and contacting the product with a specific metal hydrogen complex compound. CONSTITUTION:The objective glucoside can be produced by decoloring (A) an alkyl glucoside produced by reacting a sugar with a higher alcohol or by reacting a sugar with a lower alcohol and then with a higher alcohol with (B) hydrogen peroxide and contacting the decolored product with (C) a metal complex compound of formula M(BH4)x [M is alkali metal, Ca, Zn or (CH3)4N; x is 1 when M is alkali metal or (CH3)4N and x is 2 when M is Ca or Zn] (preferably sodium borohydride), thereby decomposing the residual hydrogen peroxide.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing alkyl glycosides, and more particularly to a method for producing alkyl glycosides that are excellent in hue, odor, and stability.

[Prior art and problems to be solved by the invention] Alkyl glycosides, which are surfactants of Pi derivatives, are mild surfactants, and even though they are nonionic surfactants, they are themselves stable. Not only does it generate bubbles (
, is known to act as a foam stabilizer with respect to other anionic surfactants, and has been attracting attention in recent years.

However, although alkyl glycosides have remarkable properties as new surfactants as described above, it is also true that their actual production is accompanied by many difficulties. The biggest problem among them is that not only does the hue easily deteriorate due to various operations in the manufacturing process, but also that when the alkyl glycoside produced is stored, the hue deteriorates orally compared to immediately after storage. there were.

In particular, in order to obtain an alkyl glycoside with a good hue that will not cause any problems when blended into actual products, a step of decolorizing the alkyl glycoside obtained by the reaction of M group and higher alcohol is essential. However, when alkyl glycosides are decolorized using hydrogen peroxide, which is conventionally known as an effective decolorizing agent, deterioration of odor such as generation of rancid odor and aldehyde odor during storage and color change over time occur. A new problem arises: deterioration.

Therefore, research has been conducted to improve the hue of alkyl glycosides and to prevent oral deterioration of the hue, that is, to stabilize the hue, and several solutions have been proposed.

For example, first of all, high alcohol and single alcohol! A method in which the reaction is carried out in the presence of an acid catalyst composition comprising an acid catalyst and a reducing agent, as described in JP-A-59-139397, in the reaction step of producing an alkyl glycoside by reaction with A method using the acid form of an anionic activator as a catalyst as described in EP 0 132 043 and a method using an organic base to terminate the reaction as described in EP 0 132 046 Methods for performing summation have been proposed. In addition, in the step of separating the produced alkyl glycoside from the unreacted recovered alcohol, the color deterioration is particularly significant due to the high viscosity and poor thermal stability of the alkyl glycoside, so a method of adding a viscosity reducing agent (Japanese Patent Laid-Open No. 62-192396) The following proposals have been made:

Furthermore, JP-A-1-290692 proposes a method for improving the color of a glycoside composition by bringing the glycoside composition containing colored humins into contact with hydrogen or a hydrogen source such as sodium borohydride. .

However, even after performing these hue improvement methods,
The hue of the alkyl glycoside obtained is not satisfactory for use as is in actual products. Unexamined Japanese Patent Publication 1986-33
Publication No. 193 proposes bleaching the alkyl glycoside finally obtained by production using a hydrogen peroxide and sulfur dioxide source, but in this case, the alkyl glycoside is bleached immediately after the treatment compared to before the treatment. Glycoside odor deteriorates. Furthermore, when the alkyl glycoside is stored, new problems arise such as deterioration of color and odor over time, and this cannot be said to be a satisfactory solution.

As described above, when alkyl glycosides are decolorized using hydrogen peroxide, there is a problem in ensuring the stability of hue and odor during storage. In other words, this point remains unresolved, and the challenge is to resolve it.

[Means to solve the problem]

The present inventors have conducted intensive studies to solve the problems encountered when decolorizing alkyl glycosides using hydrogen peroxide.
It was discovered that the deterioration in hue and odor of alkyl glycosides decolorized with hydrogen peroxide described above during storage is due to the hydrogen peroxide remaining in the alkyl glycosides after decolorization. It can be efficiently decomposed by contacting with a specific metal hydrogen complex compound, and when such treatment is performed, the obtained alkyl glycoside has extremely good stability in terms of color and odor during storage. They discovered this and completed the present invention.

That is, in the present invention, sugar and higher alcohol are reacted,
Alternatively, an alkyl glycoside obtained by reacting a sugar and a lower alcohol and then a higher alcohol is decolorized with hydrogen peroxide, and then further prepared by the following formula (
I) % formula % (I) (where n is an alkali metal, Ca, Zn or (CH
z)<N, and when the gate is an alkali metal or (C10)J, when LM is Ca or Zn, X is 2. ) The present invention provides a method for producing an alkyl glycoside with stable hue and odor, which comprises decomposing residual hydrogen peroxide by contacting the compound with a metal hydrogen complex compound represented by the following formula.

As stated above, the purpose of the present invention is to obtain alkyl glycosides with good color and odor by efficiently decomposing hydrogen peroxide remaining in alkyl glycosides by contacting them with a specific metal hydrogen complex compound. ,
This method is distinct from the method described in JP-A-1290692, in which an alkyl glycoside containing a dye base is reductively decolorized using hydrogen or a hydrogen source.

Incidentally, the method disclosed in JP-A-1-290692 cannot provide an alkyl glycoside with a sufficiently satisfactory hue (see Comparative Example 3).

The alkyl glycoside according to the present invention can be obtained by a well-known synthesis method, such as a method in which tin and a higher alcohol are directly reacted in the presence of an acid catalyst, or a method in which saccharides are preliminarily reacted with a lower alcohol such as methanol, ethanol, propatool or butanol. It may be obtained by any method of reacting with alcohol to form a lower alkyl glycoside and then reacting with higher alcohol.

Examples of the higher alcohol used as a raw material for the alkyl glycoside according to the present invention include alcohols represented by the following formula (II).

RO(AO), H...(II) (wherein, R represents a linear or branched argyl group or alkenyl group having 6 to 22 carbon atoms, or an alkylphenyl group, and ^ represents a carbon number of 2 to 4 represents an alkylene group, and n is a number whose average value is 0 to 5.) Monosaccharides, oligosaccharides, or polysaccharides are used as the saccharides that are the raw materials for the alkyl glycosides according to the present invention.

Specific examples of monosaccharides include aldoses, such as allose, aldrose, glucose, mannose, gulose,
Examples include idose, galactose, sucrose, ribose, arabinose, xylose, and lyxose. Oligo 1! Specific examples of the genus include maltose, lactose, sucrose, maltotriose, and the like. Specific examples of polysaccharides include hemicellulose, inulin, dextrin, dextran, xylan, starch, and hydrolyzed starch.

The reaction for producing alkyl glycoside in the present invention is carried out using the above-mentioned starting materials and according to known methods regarding conditions such as catalyst and reaction temperature (Japanese Patent Publication No. 47-24532,
USP No. 3839318, εP No. 092355, JP-A-59-139397, JP-A-58189195, etc.).

In the present invention, decolorization of alkyl glycosides with hydrogen peroxide is efficiently carried out in a system in which the pH is maintained alkaline. The amount of hydrogen peroxide used for decolorization is 0.05 to 1O based on the dry solid content of the alkyl glycoside in pure form.
% by weight, preferably 0.1-5% by weight. The alkyl glycoside to be decolorized is used in the form of an aqueous alkyl glycoside solution containing an alkyl glycoside dry solids content of 15 to 75% by weight, preferably 20 to 65% by weight.

During the hydrogen peroxide treatment, it is preferable to maintain p)l of the aqueous alkyl glycoside solution at 8 or more, preferably from 8 to 14, more preferably from 8 to 12. As the pH of the aqueous alkyl glycoside solution decreases with the hydrogen peroxide treatment, an alkali may be added as appropriate throughout the treatment to maintain the PL+ of the system at 8 or higher.
For example, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, or alkali metal carbonates such as sodium carbonate and potassium carbonate are used in the form of solid or aqueous solutions.

In the hydrogen peroxide treatment in the present invention, a required amount of hydrogen peroxide is added to an aqueous alkyl glycoside solution, and the mixture is stirred or aged for 3
This is carried out for 0 minutes or more, preferably for 1 hour or more. Hydrogen peroxide is usually added in the form of a 3 to 60% by weight aqueous solution, but is not particularly limited. Additions can be made in - bracket additions as well.
It may be added in portions. In addition, the processing temperature is 5 to 100'C1
Preferably 20-80°C1, more preferably 30-70°C
It is °C.

Examples of the metal hydrogen complex compound represented by formula (I) used in the present invention include lithium borohydride, sodium borohydride, potassium borohydride, tetramethylammonium borohydride, calcium borohydride, and hydrogen borohydride. Examples include zinc borohydride, and sodium borohydride is particularly preferred.

The metal hydrogen complex compound represented by formula (I) used in the present invention is added to an aqueous alkyl glycoside solution that has been decolorized with hydrogen peroxide in the form of a powder, an aqueous solution, or an alkaline aqueous solution. The amount of the metal hydrogen complex compound to be added is 0.05 to 2 molar equivalents, preferably 0.3 to 1 molar equivalent, relative to the hydrogen peroxide used for decolorization. The treatment temperature is 10-80'C1, preferably 20-50'C.

The time required for the treatment is 0.25 to 5 hours, preferably 0.25 to 5 hours.
It takes 5 to 1 hour. The pH at which the treatment is carried out is between 7 and 12, preferably between 8 and 10, and can be adjusted by adding a suitable base, such as sodium hydroxide, prior to the addition of the metal hydrogen complex.

Next, the excess metal hydrogen complex remaining in the system is decomposed with acid to complete the treatment. As the acid, sulfuric acid, para-toluenesulfonic acid, etc. can be used. The pH is kept slightly acidic by gradually adding acid to the aqueous alkyl glycoside solution containing excess metal hydrogen complex under stirring.

The time required to decompose the metal hydrogen complex is about 0.5 hours.

After the decomposition is complete, the pll is returned to neutrality by adding a suitable base, such as sodium hydroxide.

By the above treatment, residual hydrogen peroxide in the aqueous alkyl glycoside solution can be completely decomposed. The amount of hydrogen peroxide remaining in the system can be determined using, for example, the iodine titration method (Nihon Yakugaku Kinsen "Hygiene Test Method Commentary" p. 192, published in 1973).
can be easily measured by

〔Effect of the invention〕

The present invention is characterized in that an aqueous alkyl glycoside solution decolorized using hydrogen peroxide is treated with a metal hydrogen complex compound represented by the formula (I). The surprising effect is that the color and odor last for a long time.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited by these Examples.

Example 1 (a) Decyl alcohol 11400g (72,0
mol), anhydrous glucose 3240g (I8, On+
ol) and p-toluenesulfonic acid monohydrate 96g (
0.5 mol) was heated and stirred in a 301 reaction tank. 95
After raising the temperature to °C, the system internal pressure was set to 40+mm and 11 g to start the dehydration reaction.

At this time, Nt was blown into the reaction mixture at a rate of 5 Nl/+in to efficiently remove the generated water. After 5 hours, after confirming that the glucose was completely consumed,
The vacuum was released, the mixture was cooled and neutralized with 20 g of NaO)I. After filtering off the by-product polysaccharide, 4270 g of alkyl glycoside and 8460 g of unreacted recovered alcohol were separated under distillation conditions of 130° C. and 10.4 mdg. Then, a portion of the solid content was dissolved in water to prepare a dark red 50% aqueous solution of alkyl glycoside.

(b) 400g of this alkyl glycoside aqueous solution
Heated to 5°C, added 3% Na0l-1 aqueous solution Log to adjust pll to 9, and then added 30% hydrogen peroxide (Ih
4 g of O3) was added and stirring continued for 30 minutes at 45°C.

During this time, by appropriately adding a 3% Na0tl aqueous solution, p
u was maintained at 8.7-9.3.

Next, 0.67 g of sodium borohydride was added and stirred at room temperature for 30 minutes. Add 5% para-toluenesulfonic acid aqueous solution, adjust PL to 5, stir for 30 minutes, and then add 3% N
a OII aqueous solution was added to adjust the pH to 7. The amount of residual HtO□ in the obtained aqueous alkyl glycoside solution was so small that it could not be determined by iodometric titration.

Example 2 1 in place of sodium borohydride in Example 1
．． A similar treatment was performed using 2 g of calcium borohydride to obtain an aqueous alkyl glycoside solution.

Comparative Example 1 An aqueous alkyl glycoside solution was obtained in exactly the same manner as in Example 1, except that the sodium borohydride treatment was not performed.

The amount of remaining 11□0□ was 0.14 wL%.

Comparative Example 2 0 instead of sodium borohydride in Example 1
．． A similar treatment was performed using 38 g of sodium sulfite to obtain an aqueous alkyl glycoside solution.

Comparative Example 3 JP-A-1. The alkyl glycoside was decolorized by the method described in Japanese Patent No. 290692.

That is, a dark red 50% aqueous solution of alkylglycosylation was prepared in the same manner as in Example 1(a). 200 g of this alkyl glycoside aqueous solution was mixed with 12% by weight of sodium borohydride.
The mixture was completely mixed with 4.2 g of a 14N aqueous sodium hydroxide solution containing 14N sodium hydroxide solution, and left at room temperature for 4 days.

Test Example 1 The aqueous alkyl glycoside solutions obtained in Examples 1 and 2 and Comparative Examples 1 and 2.3 were adjusted to have an alkyl glycoside content of 30% and were stored stably in air at 50°C for 120 hours. A sex test was conducted. The results are shown in Table 1.

In Table 1, the lower the Gardner value, the better the hue. Incidentally, the odor was judged by five panelists.

Table 1 Table 1 shows that the method of the present invention provides alkyl glycosides with well stabilized hue and odor.

Claims (1)

[Claims] 1. After decolorizing an alkyl glycoside obtained by reacting a sugar and a higher alcohol, or by reacting a sugar and a lower alcohol and then reacting a higher alcohol with hydrogen peroxide. , and further the following formula (I) M(BH_4)_x...(I) (However, M is an alkali metal, Ca, Zn or (CH_3
)_4N, and M is an alkali metal or (CH_3)_
When 4N, x is 1; when M is Ca or Zn, x is 2. ) A method for producing an alkyl glycoside with stable hue and odor, which comprises decomposing residual hydrogen peroxide by contacting with a metal hydrogen complex compound represented by 2. The method for producing an alkyl glycoside according to claim 1, wherein the metal hydrogen complex represented by formula (I) is sodium borohydride.