JP2001151789A - Method for producing alkyl glycoside - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an alkyl glycoside good in hue and odor. SOLUTION: An acidic catalyst in an amount of 0.001-0.10 mol based on 1 mol of a saccharide is used and the reaction temperature is kept at 110±10 deg.C in a stage at <=80 mol% rate of reaction and 90±10 deg.C in a stage of >90% rate of reaction. The reaction is carried out within the range so that the reaction temperature does not to exceed 120 deg.C through the whole stage when the saccharide and a higher alcohol are used or a reaction product of the saccharide with a lower alcohol and the higher alcohol are used to produce the alkyl glycoside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an alkyl glycoside, and more particularly to a method for producing an alkyl glycoside having good hue and odor.

[0002]

BACKGROUND OF THE INVENTION Alkyl glycosides, which are sugar derivative surfactants, are low-irritant surfactants and are stable in spite of being nonionic surfactants. It not only creates bubbles,
It is known to act as a foam stabilizer for other anionic surfactants, and has recently been receiving attention.

[0003] However, although alkyl glycosides have remarkable properties as new surfactants as described above, their actual production involves many difficulties.

[0004] Alkyl glycosides are produced by reacting saccharides and alcohols. Among them, the biggest problem is that various operations in the production process easily cause deterioration of hue.

For this reason, methods for preventing hue deterioration in the manufacturing process have been studied, and some solutions have been proposed. For example, first, in a reaction step of producing an alkyl glycoside by reacting a higher alcohol with a monosaccharide, an acid catalyst composition comprising an acid catalyst and a reducing agent as described in JP-A-59-139397. A reaction in the presence, a method using an acid form of the anionic activator as a catalyst as described in EP 0 132 043, or a reaction as described in EP 0 132 046. A method of neutralizing with an organic base when stopping is proposed. In the step of separating the formed alkyl glycoside from the unreacted recovered alcohol by distillation, the viscosity of the alkyl glycoside is high and the heat stability is poor. 62-192396), but the hue of the alkyl glycoside obtained by any of the methods has not been satisfactory.

Further, Japanese Patent Application Laid-Open No. 47-16413 proposes that an alkyl glycoside having a good hue can be obtained by contacting a reaction product for producing an alkyl glycoside with a basic anion exchange resin in a hydroxyl group form prior to separation. However, in this case, there is a concern that odor may be deteriorated due to generation of amine odor.

Further, Japanese Patent Application Laid-Open No. 61-33193 discloses that an alkyl glycoside finally obtained by the production is bleached using a hydrogen peroxide and a sulfur dioxide source. Apart from this, new problems such as deterioration in odor and poor storage stability have occurred, and cannot be said to be a drastic solution.

As described above, various methods have been proposed for producing alkyl glycosides having good hue. However, the hue of the obtained alkyl glycoside is not yet satisfactory or the odor is deteriorated. Neither method was a method satisfying both the hue and the odor, for example, the generation of odor.

[0009]

Means for Solving the Problems The present inventors have intensively studied a method for producing an alkylglycoside having a good hue and odor, and found that the reaction between a sugar and a higher alcohol or a reaction between a lower alcohol and a sugar. It has been found that an alkyl glycoside having a good hue and odor can be obtained by reacting the product and a higher alcohol under very specific conditions.

That is, the present invention relates to a method for producing an alkyl glycoside using a sugar and a higher alcohol or a reaction product of a sugar with a lower alcohol and a higher alcohol, wherein 0.001 to 0.10 mol of an acid is added per mol of the sugar. Using a catalyst, the reaction temperature is 110 ± 10 ° C when the reaction rate (based on the consumption of reactants of sugar or sugar and lower alcohol) is 80% or less, and the reaction temperature is higher than 90% when the reaction rate exceeds 90%. 90 ± 10
The present invention provides a process for producing an alkyl glycoside having a good hue and a good odor, wherein the reaction is carried out at a temperature of not more than 120 ° C throughout the entire process.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Monosaccharides, oligosaccharides or polysaccharides are used as saccharides as raw materials of the alkyl glycoside according to the present invention. Specific examples of monosaccharides include aldoses such as allose, altrose, glucose, mannose, gulose, idose, galactose, talose, ribose, arabinose, xylose, and lyxose. Specific examples of the oligosaccharide include maltose, lactose, sucrose, maltotriose and the like. Specific examples of polysaccharides include hemicellulose, inulin, dextrin, dextran, xylan, starch, hydrolyzed starch and the like. Of these, reducing sugars having 6 or less carbon atoms are particularly preferred.

The reactants of the sugar as the raw material of the alkyl glycoside according to the present invention and the lower alcohol include methyl glycoside, ethyl glycoside, butyl glycoside,
Examples thereof include alkyl glycosides having an alkyl group having 5 or less carbon atoms, such as amyl glycoside.

The higher alcohol which is a raw material of the alkyl glycoside according to the present invention includes an alcohol represented by the following formula (I).

RO (AO) _n H (I) wherein R represents an alkyl or alkenyl group having 6 to 22 carbon atoms, preferably 8 to 18 carbon atoms, or an alkylphenyl group, and A represents 2 to 4 carbon atoms. Wherein n is an average number of 0 to 5.) The higher alcohol is preferably used in an amount of 2 to 10 moles per 1 mole of a sugar or a reactant of a sugar and a lower alcohol. . If it is less than this range, the reaction rate decreases, and even if it exceeds this range, there is no merit from a technical / economic viewpoint as compared with the case within this range.

The acid catalyst used in the present invention includes at least one selected from paratoluenesulfonic acid, sulfuric acid, phosphoric acid, strongly acidic ion exchange resin and the like. Toluenesulfonic acid is preferred.

The amount of acid catalyst used is from 0.001 to 0.10 mol per mol of sugar or reactant of sugar and lower alcohol. When the amount of the acid catalyst is less than this range, the reaction rate is remarkably reduced. On the other hand, when the amount exceeds this range, the hue of the obtained alkyl glycoside is not good.

In the present invention, the reaction is conducted at a reaction temperature of 110 ± 10 ° C. when the reaction rate (based on the consumption of the reactant of sugar or sugar and lower alcohol) is 80% or less, and the reaction rate is 90%.
%, It is important to carry out the reaction at a reaction temperature of 90 ± 10 ° C., and to carry out the reaction at a temperature not exceeding 120 ° C. in all the steps. By carrying out the reaction under these conditions, an appropriate reaction rate is obtained, and burning of the sugar and the generated alkyl glycoside due to heating (caused by heating during the reaction) and the like are suppressed. In the present invention, the above-mentioned change of the reaction temperature range may be performed stepwise, or the reaction may be performed in a slope shape.

In the present invention, the reaction is carried out under the above-mentioned very specific reaction conditions. In this respect, conventionally known methods (JP-B-47-24532, US Pat.
P-092355, JP-A-59-139397, JP-A-58-189195
No.).

[0019]

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

Example 1 1583 g (10.0 mol) of n-decyl alcohol, 360 g (2.0 mol) of anhydrous glucose and paratoluenesulfonic acid monohydrate 1.
33 g (7.0 × 10 ⁻³ mol) was heated and stirred in a 3 L reaction tank. 95
After the temperature was raised to ° C., the pressure in the system was set to 40 mmHg, and the dehydration reaction was started. At this time, nitrogen was blown into the reaction mixture at a rate of 200 ml / min to efficiently remove generated water. Further heating was performed to raise the first-stage reaction temperature to 115 ° C. After the temperature reached 115 ° C., the reaction mixture was sampled every hour,
When the reaction rate obtained from the glucose consumption reached 80%, the second-stage reaction temperature was lowered to 95 ° C. Thereafter, a dehydration reaction was performed until the reaction rate became 96% or more. After the reaction,
The vacuum was released and the mixture was neutralized with 0.28 g of NaOH. After filtering off the by-product polysaccharide and unreacted glucose, 524 g of alkyl glycoside and 1419 g of unreacted recovered alcohol were separated under a distillation condition of 180 ° C. and 0.4 mmHg. Next, a part of the solid content was dissolved in water to prepare a pale yellow 50% aqueous solution.

Example 2 Example 1 was repeated except that the first-stage reaction temperature in Example 1 was set to 120 ° C. and the reaction temperature was lowered to 85 ° C. at a rate of 0.1 ° C./min.
In the same manner as in the above, an alkyl glycoside was obtained.

Example 3 An alkyl glycoside was obtained in the same manner as in Example 1 except that the first-stage reaction temperature was 110 ° C. and the second-stage reaction temperature was 95 ° C.

Example 4 An alkyl glycoside was prepared in the same manner as in Example 1 except that 360 g (2.0 mol) of anhydrous glucose in Example 1 was changed to 388 g (2.0 mol) of methylglucoside, and methanol produced by the reaction was efficiently removed. Obtained.

Comparative Example 1 An alkyl glycoside was obtained in the same manner as in Example 1 except that the reaction temperature in the first stage in Example 1 was 115 ° C. and the reaction was terminated as it was.

Comparative Example 2 An alkyl glycoside was obtained in the same manner as in Example 1, except that the first-stage reaction temperature was changed to 130 ° C. and the second-stage reaction temperature was changed to 80 ° C.

Comparative Example 3 An alkyl glycoside was obtained in the same manner as in Example 1 except that the reaction temperature in the first stage in Example 1 was 105 ° C. and the reaction was terminated as it was.

Comparative Example 4 360 g (2.0 mol) of anhydrous glucose in Example 1 was changed to 388 g (2.0 mol) of methyl glucoside, methanol generated by the reaction was efficiently removed, and the first-stage reaction temperature was 115 ° C.
An alkyl glycoside was obtained in the same manner as in Example 1 except that the reaction was terminated as it was.

The relationship between the reaction rate and the reaction temperature in Examples 1 to 4 and Comparative Examples 1 to 4 is shown in FIG. Example 1
And the color of the alkyl glycoside at the end of the reaction obtained by Comparative Examples 1-4 and Comparative Examples 1-4, and at the time of commercialization (after removing excess alcohol, a 50% aqueous solution of alkyl glycoside was obtained)
Table 1 shows the evaluation results of the hue and the odor.

[0029]

[Table 1]

Note: *: The hue at the time of commercialization is the hue of a 50% aqueous solution of alkyl glycoside after removing excess alcohol.

[0031]

According to the present invention, an alkyl glycoside having a very excellent color and odor can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a reaction rate and a reaction temperature in Examples 1 to 4 and Comparative Examples 1 to 4.

Claims (3)

[Claims] When producing an alkyl glycoside using a sugar and a higher alcohol, 0.001 to 0.001 to 1 mole of the sugar is used.
Reaction rate (based on sugar consumption) using 0.10 mol acid catalyst
Is 80% or less, the reaction temperature is 110 ± 10 ° C., and when the conversion exceeds 90%, the reaction temperature is 90 ± 10 ° C.,
A method for producing an alkyl glycoside, wherein the reaction is carried out at a reaction temperature not exceeding 120 ° C. throughout all the steps. 2. In producing an alkyl glycoside using a reaction product of a sugar and a lower alcohol and a higher alcohol, an acid catalyst in an amount of 0.001 to 0.10 mole per mole of the sugar is used, and the reaction rate (sugar and lower alcohol and The reaction temperature is 110 ± 10 ° C. when the reaction rate is less than 80%, and the reaction temperature is 90 ± 10 ° C. when the conversion exceeds 90%.
C., and the reaction is carried out at a reaction temperature not exceeding 120 ° C. throughout all the steps. 3. The higher alcohol is a straight-chain or branched-chain saturated or unsaturated alcohol having 8 to 18 carbon atoms or an alkylene oxide adduct thereof, and the acid catalyst is paratoluenesulfonic acid, sulfuric acid, phosphoric acid or a strongly acidic ion. 3. The method for producing an alkyl glycoside according to claim 1 or 2, wherein the sugar is at least one of the exchange resins, and the sugar is a reducing sugar having 6 or less carbon atoms.