KR19990041610A - Method for producing alkylglycoside having excellent color and transparency - Google Patents

Abstract

In the present invention, by using magnesium oxide having a very specific surface area in the neutralization step during the APG production alone as a neutralizing agent, alkali hydroxide is used alone, or when alkali hydroxide and magnesium oxide are used together. It minimizes the browning, namely, the deterioration of color quality and the incorporation of a large amount of pigment in the recovered alcohol. In particular, magnesium oxide is used in the form of fine powder with a specific surface area of 50 m ² / g or more, as required, so that a small amount of magnesium oxide can be used to prepare a product having excellent color quality and transparency under excellent cleaning power even by a simple bleaching process. In addition, the chromaticity of the distilled alcohol is less than APHA 30 so that it can be reused immediately without any post-treatment.

Description

Method for producing alkylglycoside having excellent color and transparency

The present invention relates to an alkyl polyglycoside-based nonionic aqueous surfactant having excellent color quality and transparency, and a preparation method thereof.

Alkyl polyglycoside (APG) -based nonionic surfactant has the advantage that it is possible to greatly reduce the water pollution problem even when used as a detergent by using a natural raw material is excellent in biodegradability and low skin irritation. Due to these environmentally friendly advantages, various preparation methods have been reported, such as WO 90-218,084, WO 90-194,262, European Patent Publication Nos. 0,301,298 and 0,357,969. A method of directly reacting carbohydrate-based raw materials with excess higher fatty alcohols is mainly used. However, when the alkyl polyglycoside is reacted or the excessive unreacted fatty alcohol is removed, color development may occur due to browning, which greatly affects the color quality of the final product. Therefore, many studies have been carried out to avoid such a phenomenon, in particular, a method for producing a pale yellow and color stable APG is disclosed in European Patent Publication No. 0,362,671.

The reason why APG is pale yellow is due to deterioration of mono-saccharides when excess alkali is used in the neutralization stage in APG production, and it is possible to reduce the color development by accurate neutralization during neutralization, but it is impossible to completely suppress it. to be. Therefore, if the color is already developed, there is no choice but to limit the application as a household detergent without going through the bleaching process in the final stage. In consideration of this point, each manufacturer undergoes a bleaching process using a bleach such as H ₂ O ₂ as a post-treatment during APG production.

In addition, to increase the bleaching effect, a magnesium compound is used, which is a general technique known since 1963, and is widely used in various fields, for example, in the form of magnesium oxide in the petrochemical industry. WO 92-08,789 describes a method for producing APG having better color quality with microbial stability by post-treatment of oxidative bleaching and reducing agent such that the final product has a pH of 11.0 or more using magnesium compounds. Processes for preparing APG using are disclosed in WO 94-02,494, 94-24,139 and 95-23,169.

However, it is difficult to manufacture satisfactory APG in terms of chromaticity, and in particular, since color reversion occurs during the storage period, the detergent industry must undergo a re-bleaching process to satisfy consumer needs. . The reason that it is impossible to commercialize by normal one-time bleaching process is because the color development phenomenon has progressed too much in the pre-bleaching stage. Therefore, in order to obtain APG with excellent color quality by simple bleaching process, preserving the chromaticity of the aqueous solution of APG in the pre-bleaching stage as much as possible It can be seen that it is important.

In addition, when the color development phenomenon is too advanced, the pigment is mixed with the recovered alcohol in the process of recovering the excess aliphatic alcohol used in the production of APG, it is inconvenient to go through a costly purification process such as distillation in the recovery alcohol reuse This will also reduce the recycling rate of recovered alcohol.

In the present invention, by applying a magnesium compound by a special method in the neutralization step in the production of APG, not only the APG having excellent color quality by a simple bleaching process, but also maintaining the chromaticity of the recovered alcohol can be reused immediately without additional purification process. There is a purpose.

In order to help the understanding of the present invention, the chromaticity and detergency in the production of APG will be described first.

First, the chromaticity of APG and its characteristics as a surfactant vary depending on the carbon chain length of the aliphatic alcohol used when preparing APG. For the classified Generally, the number of carbon atoms is produced by not more than 10 aliphatic alcohols (C _~10) APG is a color quality is produced by a relatively high contrast, having a carbon number of 12 or higher aliphatic alcohols (C _12~) APG is color quality This is thirteen. In the former case, however, the hydrophilic property is strong and has very good dissolution properties. The latter has a strong lipophilic property, which is suitable as a humectant or an emulsifier. Should be used.

Second is the molar ratio of fatty alcohols and carbohydrates. For example, when the molar ratio of aliphatic alcohol: glucose is 5: 1 or higher, the aliphatic alcohol has a high color quality and is easy to determine the end point of the reaction step. (degree of oligomerization) is low, detergency. On the other hand, when the molar ratio of aliphatic alcohol: glucose is 3.0 to 4.5: 1 or less, the color quality is inferior, but the latter is preferable when used as a detergent since washing power is increased due to an increase in the degree of oligomerization.

Third, when the excess aliphatic alcohol is removed from the alcohol solution containing APG as above, it must be distilled under high temperature and high vacuum conditions of 180-200 ° C or higher. At about 130 ° C or higher, APG is absolutely free from oxidizing gases such as oxygen. Should be blocked. Otherwise, the oxidation reaction occurs, which adversely affects the color of the produced APG as well as distilled alcohol.

Fourth, neutralization conditions such as pH control. APG is obtained through the steps of reaction, neutralization, distillation, dilution and bleaching, and it is very difficult to control pH during the neutralization process. If the neutralization is insufficient, the reversible reaction in which the APG is already decomposed into carbohydrates and alcohol during the removal of excess alcohol (for example, distillation) proceeds, and at the same time, caramel formation may occur due to polymerization between the separated carbohydrates. In the case of excessive alkali, the color quality deterioration phenomenon due to the acceleration of browning changes appears, so accurate neutralization such as pH 7.0-8.0 is required. In addition, the amount of heat the reactants have during neutralization, that is, the temperature and time required, also affects the pH and color quality in the dilution step.

In view of the relationship between color and cleaning power in APG production, the present inventors adopted the following method to obtain high quality APG in terms of cleaning power and chromaticity with good color of recovered alcohol.

First, the composition of the carbon chain is C ₈ 40% or less, C ₁₀ 30% or less, C ₁₂ 30% or more, C ₁₄ 5% or more, preferably C ₈ 30% or less, C ₁₀ 20% or less, C ₁₂ 40% or more , C ₁₄ aliphatic alcohol mixture having a ratio of 10% or more to 3.0 to 4.5 times, preferably 3.5 to 4 times in molar ratio to carbohydrates such as glucose and then acid catalyst such as PTSA (Para-Toluene Sulfonic Acid) The mixture is added at 0.007 mol / saccharide mol and reacted so that the carbohydrate-free unreacted substance is 3% or less, preferably 1% or less, with respect to the total reactants at about 80 to 200 minutes at 110 to 125 ° C. at an absolute pressure of 16 to 20 torr.

In addition, the fine powder of magnesium oxide having a specific surface area of 50 m ² / g or more, preferably 80 m ² / g or more and not hygroscopic, having a moisture content of 5% or less and preferably 3% or less by measuring in advance 0.5 to 1.0 mol / PTSA mol, preferably 0.65 to 0.75 mol / PTSA mol, in the form of, and the pH of the reaction solution is 7.0-70 while stirring for 20-40 minutes at 85-105 ° C, preferably about 95 ° C. Neutralize to 8.0.

Subsequently, the distillation residue obtained by distillation so that the unreacted fatty alcohol is 2% or less, preferably 1% or less under high temperature and high vacuum is mixed with ion purified water so that the water content is 40 to 60%, preferably 50%, and then hydrogen peroxide. It is possible to prepare an aqueous solution of APG having excellent chromaticity and transparency by going through a decolorization process.

In the present invention, by using magnesium oxide having a very specific surface area in the neutralization step during the APG production alone as a neutralizing agent, alkali hydroxide is used alone, or when alkali hydroxide and magnesium oxide are used together. It minimizes the browning, namely, the deterioration of color quality and the incorporation of a large amount of pigment in the recovered alcohol. In particular, magnesium oxide is used in the form of fine powder with a specific surface area of 50 m ² / g or more, as required, so that a small amount of magnesium oxide can be used to prepare a product having excellent color quality and transparency under excellent cleaning power even by a simple bleaching process. In addition, the chromaticity of the distilled alcohol is less than APHA 30 so that it can be reused immediately without any post-treatment.

<Example 1>

Aliphatic alcohols with a composition of carbon ₈ 22%, C ₁₀ 17%, C ₁₂ 47%, and C ₁₄ 14% at 116-120 ° C using 155 g of PTSA for 100 Kg of a mixture of 3.5: 1 After reacting for about 100 minutes at 20 torr absolute pressure, 22 g of magnesium oxide in a finely divided form having a specific surface area of 100 m ² / g and 1% of moisture by micropore was added thereto and stirred at a constant temperature of 95 ° C. for 30 minutes. There is no leak after distillation under absolute pressure of 0.5 torr, ~ 200 ℃, the distillation residue having a residual alcohol content of 2% is sufficiently mixed with 34 kg of ionic purified water, the same amount as the distillation residue. Subsequently, 0.9 kg of 30% sodium hydroxide aqueous solution was added at 50 ° C, dissolved for 10 minutes, 1.7 kg of 28% hydrogen peroxide solution was added and decolorized at 85 ° C for 2 hours while stirring, and then the color and transparency were measured. Was colorless and transparent, and APG 30, AP9.6 containing 49.6% water with transmittance of 95% T was obtained. The color of recovered alcohol was APHA 0.

Analytical Instruments: Lovibond Tintometer PFX 190 (color)

Milton Roy's Spectronic 20D (transmittance)

<Example 2>

25 g of magnesium oxide fine powder having a specific surface area of 80 m ² / g was added to the reaction product prepared by the same method as in Example 1, and the remaining method was prepared in the same manner as in Example 1 to measure chromaticity and transparency. . Visually, colorless and transparent, APG containing 49.5% of moisture, APHA 48 and 93% T of transmission, was obtained by instrumental analysis. The color of recovered alcohol was APHA 10.

Comparative Example 1

35 g of magnesium oxide fine powder having a specific surface area of 30 m ² / g was added to the reaction product prepared by the same method as in Example 1, and the rest of the methods measured the chromaticity and transparency of the APG obtained in the same manner as in Example 1. APHA 80 and 48.6% moisture APG containing 60% T of transmission were obtained. The color of recovered alcohol was APHA 20.

Comparative Example 2

62 g of magnesium oxide fine powder having a specific surface area of 10 m ² / g was added to the reaction product prepared by the same method as in Example 1, and the remaining method was prepared in the same manner as in Example 1 to measure chromaticity and transparency. As a result, APHA 190 and APG containing 49.5% of water having a transmittance of 45% T (translucent) were obtained. The color of recovered alcohol was APHA 30.

Comparative Example 3

All the preparation methods were the same as in Comparative Example 1, and APG 320 and Transmittance were measured by preparing APG using 104 g of 30% aqueous sodium hydroxide solution and 11 g of magnesium oxide having a specific surface area of 65 m ² / g as neutralizing agents. It was 25% T (opaque) and the color of recovered alcohol was APHA 80.

TABLE 1

Experiment Section Neutralizer Input Color Transparency Recovered Alcohol Remarks

(Specific surface area) (g) [before / after bleaching] [after bleaching] chromaticity [visual observation]

Example 1 Mg0 22 G # 5.4 / APHA 30 95% T AHPA 0 Colorless Transparent

(100m ² / g)

Example 2 Mg0 25 G # 6.0 / APHA 48 93% T AHPA 10 Colorless and Transparent

(80m ² / g)

Comparative Example 1 Mg0 35 G # 8.7 / APHA 80 60% T AHPA 20 White Transparent

(30m ² / g)

Comparative Example 2 Mg0 62 G # 9.5 / APHA 190 45% T AHPA 30 White Translucent

(10m ² / g)

Comparative Example 3 NaOH 30% 104 G # 15.5 / APHA 320 25% T AHPA 80 Pale Yellow Opaque

Mg0 11

(65m ² / g)

Claims (11)

In preparing alkylpolyglycoside nonionic surfactants, A method for producing APG having excellent color and transparency by neutralizing using a magnesium oxide fine powder having a specific surface area of 50 m ² / g or more as a neutralizing agent and not absorbing moisture. The method of claim 1, A method of obtaining distilled alcohol having a degree of chromaticity that can be recycled without special refining process because the color of the unreacted alcohol recovered by distillation after neutralization when the APG is manufactured by the above process is excellent. The method according to claim 1 or 2, The specific surface area of magnesium oxide is 80 m ² / g or more. The method according to any one of claims 1 to 2, Wherein the acid catalyst is p-Toluene Sulfonic Acid (PTSA). The method according to any one of claims 1 to 2, A method in which the amount of magnesium oxide is 0.5 to 1.0 in molar ratio relative to PTSA. The method according to any one of claims 1 to 2, Neutralization at 85-105 degreeC for 20-40 minutes. The method according to any one of claims 1 to 2, And distilling the unreacted alcohol after neutralization until the fatty alcohol content in the concentrated APG after distillation is 2% or less. The method of claim 7, wherein A method of using a batch distillation apparatus or a continuous distillation apparatus in a distillation process. The method according to any one of claims 1 to 2, Cooling the concentrated APG after distillation and diluting with ionized water. The method according to any one of claims 1 to 2, And decolorizing using hydrogen peroxide. In preparing alkylpolyglycosides (APG), a) mixing a higher fatty alcohol having 8 to 22 carbon atoms with glucose in the presence of an acid catalyst and reacting until the content of unreacted glucose is 3% or less; b) administering magnesium oxide alone to the reaction product and neutralizing at 85 to 105 ° C. for 20 to 40 minutes; c) distilling the neutralized reactant until an unreacted alcohol content is 2% or less; d) cooling and diluting the concentrated APG; And e) decolorizing the diluted APG using hydrogen peroxide Alkylpolyglycoside (APG) production method comprising a.