KR20050106676A - Method for preparing of alkyl poly glycosides - Google Patents

Abstract

 The present invention relates to a method for preparing an alkylpolyglycoside, and more particularly, by providing a method for quickly and accurately checking the pH of a neutralized product in a neutralization step of an alkylpolyglycoside manufacturing process, and having excellent color stability and transparency. Polyglycosides are provided.

Description

Method for producing alkyl polyglycoside {METHOD FOR PREPARING OF ALKYL POLY GLYCOSIDES}

[TECHNICAL FIELD OF THE INVENTION]

The present invention relates to a method for preparing alkylpolyglycoside, and more particularly, to a method for quickly and accurately measuring pH in a neutralization step of an alkylpolyglycoside manufacturing process.

[Private Technology]

Alkyl polyglycosides (APGs) are made by reacting a carbohydrate-based raw material such as glucose with excess higher fatty alcohols in the presence of an acid catalyst, neutralizing the acid catalyst with alkali, and then removing the unreacted fatty alcohols remaining in the reactants. It is a nonionic surfactant obtained. By using the alkylpolyglycoside-based natural raw materials, not only the skin irritation is low, but also excellent in biodegradability, when used as a detergent, there is an advantage that can greatly reduce the water pollution problem.

As a method for preparing alkylpolyglycoside, a method for preparing lauryl glucoside and acetyl glucoside from acetobromoglucose and aliphatic alcohol in the presence of a base in Austrian Patent No. 135,333 and glucose using hydrogen chloride as an acidic catalyst And a method of synthesizing directly from lauryl alcohol, and a method for preparing alkyl glucoside from pentaacetyl glucose and aliphatic alcohol in the presence of anhydrous zinc chloride of German Patent No. 611,055, and malto to fatty alcohol having 8 or more carbon atoms of German Patent No. 593,422. Seeds and lactosides and their use as surface active agents are known. The patent describes cetyl maltoside to improve the washing effect of soap, which explains that cetyl maltoside is effective as a lime soap dispersion medium.

In the 60's and 70's, glucose was reacted directly with excess alcohols and acids as catalysts, or lower alcohols or glycols as solvents and reactants to obtain primary reaction products, which were subjected to acetal exchange with long chain alcohols. Various methods for obtaining active alkyl glycosides have been proposed. As part of this, U.S. Patent No. 3,450,690 (Gibbons et al.) Discloses a process for synthesizing alkyl glucosides from C1-8 alkanols, wherein the acidic catalyst (eg sulfuric acid) does not remain in the neutralization step and is substantially It is adjusted to an alkaline pH value of 8 or more, and heated to a temperature of 50 ~ 200 ℃ to distill off excess alcohol. In US Pat. No. 3,839,318 (Mansfield et al.), The reaction water formed during the reaction is rapidly azeotropically distilled from the reaction mixture by azeotropic distillation, and the reaction mixture can be adjusted to an alkaline pH value by neutralization with an aqueous sodium hydroxide solution (neutralization step). .) Next, a method is described in which excess alcohol is removed by a conventional method such as distillation, the reaction product is converted to an aqueous paste, and then the paste is bleached. In recent years, alkylpolyglycosides have been produced by techniques applied based on the above methods in the industry.

However, this method has a problem in that an already synthesized alkylpolyglycoside is decomposed or discolored in the "hot distillation" process of recovering unreacted alcohol after the reaction. The discoloration of alkylpolyglycosides is due to contact with high temperatures performed to distill recovery of unreacted alcohol, and the phenomenon becomes more severe as an excess of alkali is used in the previous neutralization step. In order to prevent the above problems, it is very important to maintain the pH of 7 ~ 8 in the neutralization process of the previous step. However, the intermediate, which is the neutralization stage immediately after the reaction, has a very small amount of water, which not only takes a lot of time when measuring pH, but also lacks reproducibility and thus requires a rapid and accurate determination of the neutralization endpoint.

In order to solve the problem in another way, WO 94-24139 and WO 95-18812 use a continuous distillation apparatus such as thin film evaporator (TFE) to minimize the contact time of the alkylpolyglycoside with high temperature. However, these methods require a huge investment cost and are suitable only for large-scale businesses, and are difficult to obtain excellent results because the pH is subjected to high temperature distillation in an alkaline state. Ultimately, it was most important to adjust the pH of the raw material intermediate to 7-8 before the high temperature distillation process, and therefore, the development of a rapid and accurate pH measurement method in the neutralization stage was urgently needed.

Accordingly, it is an object of the present invention to provide a method for quickly and accurately measuring pH in a neutralization step of an alkylpolyglycoside preparation process.

It is also an object of the present invention to provide a method for producing a high quality alkylpolyglycoside having excellent chromatic stability and transparency.

The present invention to achieve the above object

a) reacting the aliphatic alcohol with glucose under an acid catalyst;

b) neutralizing by adding a neutralizing agent to the reaction of step a), dissolving the neutralized in a mixture of water and ethyl alcohol to measure the pH;

c) concentrating the alkylpolyglycoside by distilling the unreacted aliphatic alcohol in the neutralization of step b);

d) diluting the concentrated alkylpolyglycoside concentrate of step c); And

e) providing a method for preparing an alkylpolyglycoside comprising the step of bleaching by adding a base and a peroxide to the diluted alkylpolyglycoside of step d).

Hereinafter, the present invention will be described in detail.

The present invention relates to a method for measuring pH quickly and accurately in the neutralization step in the alkylpolyglycoside preparation process.

Typical methods for preparing alkylpolyglycosides are represented below.

The alkylglycoside preparation method of the present invention is all conventional methods, for example

a) aliphatic alcohol and carbohydrate reaction step

This step is to react the aliphatic alcohol with carbohydrate and acid catalyst.

The aliphatic alcohol is preferably a higher aliphatic alcohol having 6 to 22 carbon atoms, the content is preferably included in a molar ratio of 1 to 10 per mole of the carbohydrate, more preferably in a molar ratio of 2.5 to 5 Will be.

The carbohydrate is preferably glucose.

The acid catalyst is preferably used ρ-TSA (ρ-toluenesulfonic acid), the content is preferably included in a molar ratio of 0.001 to 0.01 per mol of carbohydrates.

The reaction is preferably performed at 110 to 125 ° C. for about 1 to 10 hours at an absolute pressure of 10 to 100 torr. The above reaction is preferably carried out such that the carbohydrate unreacted substance is at most 3% of the total reactant.

b) neutralization

This step is to neutralize by adding a neutralizing agent to the reactant.

Preferably, the reactants have a residual moisture content of at most 1000 ppm, more preferably at most 500 ppm.

The neutralizing agent may be sodium hydroxide or magnesium oxide, in particular using magnesium oxide having a specific surface area of at least 30 m 2 / g, preferably at least 50 m 2 / g and a water content of up to 5%, preferably up to 3%. It is desirable to.

The neutralizing agent is preferably added in the form of fine powder, the content of which is preferably included in 0.5 to 2.0 mol / ρ-TSA mol, more preferably 0.60 to 1.80 mol / ρ-TSA mol.

The neutralization may be carried out by stirring for 20 to 60 minutes at atmospheric pressure or, if necessary, under vacuum at 60 to 120 ° C., and neutralizes the pH of the reaction solution to 7.0 to 8.0.

c) distillation step

This step is to distill the unreacted aliphatic alcohol in the neutralized reactant to concentrate the alkylpolyglycoside.

The distillation is carried out at high temperature and high vacuum, it is preferable to distill so that the unreacted aliphatic alcohol is at most 2%, preferably at most 1%.

d) dilution step

This step is to dilute the alkylpolyglycoside concentrate.

At this time, it is preferable to add distilled water to the alkyl polyglycoside concentrate so that the water content is 30-70%.

e) bleaching stage

This step is to bleach by adding a peroxide-based bleach such as base and hydrogen peroxide to the diluted alkylpolyglycoside.

The base is preferably used sodium hydroxide, the content is preferably contained in 0.5 to 5.0% by weight relative to the alkylpolyglycoside dry matter, more preferably 0.7 to 3.0 parts by weight, most preferably 0.9 to 1.5 It is included in parts by weight.

The peroxide is preferably contained in 0.2 to 3.0% by weight relative to the alkyl polyglycoside dry matter, more preferably 0.5 to 2.5 parts by weight, most preferably 0.7 to 2.0 parts by weight.

In particular, in this step, the base is added to the diluted alkyl polyglycoside and stirred for 10 to 30 minutes to adjust the pH to 12 or 13 or more, and then hydrogen peroxide is added thereto for 1 to 10 hours. It is preferred to bleach for a while.

f) after bleaching

After completion of the bleaching, additives such as NaBH4 may be further added as necessary for storage stability of the decolorized alkylpolyglycoside.

g) alcohol purification step

If the recovered alcohol contains pigments, the alcohol purification process may be adversely affected when the alcohol is recycled. Alcohol purification is carried out by breaking the double bond by the hydrogenation reaction and then removing the distillation residue by distillation.

h) distillation residue treatment step

Distillation residues are treated by incineration or the like in a way that is not harmful to the environment.

i) recoloring of alkylpolyglycosides

If the decolorized alkylpolyglycoside deteriorates in color again during the storage period, a rebleaching process using hydrogen peroxide is required.

The method for preparing alkylpolyglycoside of the present invention further includes a method for measuring pH of the sample in the above-mentioned steps, in particular in the b) neutralization step. The pH measurement method is to measure the pH by adding and stirring the sample being neutralized in a mixed solution of water and ethyl alcohol in a weight ratio of 1: 1 to 10: 1 to 10 by weight.

The method for preparing alkylpolyglycoside according to the present invention confirms that the pH of the sample being neutralized is 7 to 8, and then performs a distillation step, which is a very stable and excellent quality alkylpolyglycoside. Since the quality of the product and the recovered alcohol and the like is very excellent, there is an advantage that the post-treatment process such as the conventional f), g), h) and i) mentioned above is not essential.

Hereinafter, examples of the present invention will be described. The following examples are only for illustrating the present invention and the present invention is not limited to the following examples.

Example 1 Preparation of Aqueous Alkyl Polyglycoside Solution

After mixing 133 g of glucose with 500 g of fatty alcohol, 1 g of an acid catalyst was added and reacted at 10 -20 torr and 110-123 ° C for about 120 minutes. In the neutralization step, magnesium oxide in the form of fine powder having a specific surface area of 80 m 2 / g was used at an equivalent ratio of 1.4 times the p-TSA dose. Thereafter, 5 g of the neutralized solution was dissolved in a mixed solution of 10 g of ethyl alcohol and 5 g of water to confirm that the pH was 7-8. Then, excess alcohol was recovered to obtain 2% or less of unreacted alcohol through a distillation process, Mix with ionic purified water to 50% to obtain alkylpolyglycosides in aqueous modified form. The chromaticity (chromometry analyzer: Lovibond, Tintometer "PFX 190" for color) of the aqueous alkylpolyglycoside solution obtained by the above method was Gardner # 7.0.

30% hydrogen peroxide solution was added to the aqueous solution of alkylpolyglycoside prepared by the above method, which was stirred at 90 ° C. for 4 hours to bleach to obtain a chromaticity of the aqueous solution of alkylpolyglycoside decolorized to APHA 150.

Comparative Example 1

In the same manner as in Example 1, in the neutralization step, magnesium oxide in the form of fine powder having a specific surface area of 80 m ² / g was used in an equivalent ratio of 1.0 times the p-TSA dose, and the neutralized pH result was confirmed. Distillation was carried out without. As a result, as the temperature was increased in the distillation step, the already synthesized alkylpolyglycoside was decomposed to recover a much larger amount of alcohol than the theoretical value. The phenomenon appeared and failed to obtain the finished product.

Comparative Example 2

In the same manner as in Example 1, in the neutralization step, the magnesium oxide in the form of fine powder having a specific surface area of 80 m ² / g was used in an equivalent ratio of 1.8 times to the p-TSA dose, and the neutralized pH result was not confirmed. Distillation was carried out without. As a result, the chromaticity of 50% aqueous alkylpolyglycoside solution was Gardner # 11.0.

30% hydrogen peroxide solution was added to the aqueous solution of alkylpolyglycoside prepared by the above method, which was stirred for 4 hours at 90 ° C. for bleaching to give a color of the aqueous solution of alkylpolyglycoside decolorized to APHA 400.

Comparison of Experiment Results

The chromaticity of Example 1 and Comparative Examples 1-2 was compared, and is shown in following Table 1.

division corrector Input amount [compared to acid catalyst] Confirmation of neutralization result [pH 7-8] Decolorization Decolorization color Comparative Example 1 MgO Equivalence ratio 1: 1 unidentified Manufacturing failure Manufacturing failure Comparative Example 2 MgO Equivalence ratio 1.8: 1 unidentified G # 11.0 APHA 400 Example 1 MgO Equivalence ratio 1.4: 1 Confirm G # 7.0 APHA 150

Generally, it is very important to maintain pH 7 ~ 8 during neutralization in order to obtain APG with excellent color.If the pH neutralization result is not accurate or is not measured quickly at high temperature, the distillation process is delayed and the color of product is inferior. have. Therefore, by quickly and accurately determining the amount of neutralizing agent required by the method of rapidly measuring pH in the APG neutralization process, a stable distillation and decolorization process can be performed, and thus, an alkyl polyglycoside having excellent color and transparency can be prepared. It could be confirmed.

As described above, according to the production method of the present invention, by quickly and accurately confirming the pH of the sample prepared in the neutralization step, there is an effect of preparing an alkyl polyglycoside having excellent color stability and transparency.

Claims (5)

a) reacting the aliphatic alcohol with glucose under an acid catalyst; b) neutralizing by adding a neutralizing agent to the reaction of step a), dissolving the neutralized in a mixture of water and ethyl alcohol to measure the pH; c) concentrating the alkylpolyglycoside by distilling the unreacted aliphatic alcohol in the neutralization of step b); d) diluting the concentrated alkylpolyglycoside concentrate of step c); And e) bleaching by adding a base and a peroxide to the diluted alkylpolyglycoside of step d); Method for producing an alkylpolyglycoside comprising a.  The method of claim 1, wherein the pH of the neutralization in step b) is 7 to 8. The method of claim 1, wherein the water and ethyl alcohol mixture is a mixture of water and ethyl alcohol in a 1: 1 to 10 weight ratio.  The method of claim 1, wherein the water and ethyl alcohol mixture is added in a weight ratio of 1: 1 to 10 with respect to the neutralized product.  The method of claim 1, wherein the neutralizing agent is sodium hydroxide or magnesium oxide.