Production method of alkyl glycoside surfactant

Abstract

The invention relates to a production method of an alkyl glycoside surfactant, which mainly solves the problem of high load of a decolorization process in the existing one-step method production of the alkyl glycoside surfactant, and adopts the technical scheme that the production method of the alkyl glycoside surfactant comprises the following steps: in the presence of an acid catalyst and a reaction aid, adding a catalyst, alkyl alcohol and carbohydrate are subjected to an aldolization reaction to obtain a product material containing alkyl glycoside, the molecules of the reaction aid have an ethoxylation group, and the ethoxylation group is represented as-(OCH2CH2) mOH; wherein m is the number of OCH2CH2 in the ethoxylated group, and m is more than 2. The scheme has the characteristic that the obtained product material is low in color and luster, and can be used for producing the alkyl glycoside surfactant by a one-step method.

Description

Technical Field

[0001] The present invention relates to a method for producing an alkyl glycoside surfactant. Background Art

[0002] There are two main steps for the synthesis of alkyl glycosides, one-step synthesis and two-step synthesis. The one-step synthesis method mainly uses fatty alcohols (usually C12-C14 fatty alcohols) and carbohydrates (usually glucose or starch) as raw materials to prepare alkyl glucoside in one step. The two-step synthesis method mainly uses low-carbon alcohols (such as n-butanol) and glucose to react to generate low-carbon alcohol glycosides (such as butyl glycoside), and then uses fatty alcohols and low-carbon alcohol glycosides to undergo acetal exchange reaction to prepare alkyl glucoside. This preparation method is optimized on the one-step synthesis method. The reaction equation of the one-step method is as follows:

[0003]

[0004] n is the degree of polymerization of glucose (generally about 1.1-3); R is an alkyl group.

[0005] The one-step synthesis process is to add fatty alcohol to a reaction kettle, start stirring, add carbohydrates, the molar ratio of fatty alcohol to carbohydrates (based on the glucose units contained) is 2 to 6, add an acid catalyst (commonly used p-toluenesulfonic acid, other organic acids or inorganic acids can also be used), the catalyst amount is 1.1 to 1.5% of the carbohydrate (mass ratio), react at an absolute pressure of 3 to 10 kPa and a temperature of 105 to 115° C., cool to 70 to 80° C. after the reaction is complete, add an alkali metal oxide Or hydroxide (such as MgO or NaOH), adjust the pH to 8-10, transport the material to a two-stage evaporator (falling film evaporator and scraper evaporator), remove free fatty alcohol at a temperature of 130-180°C and a pressure below 3.3KPa (the removed fatty alcohol can be recycled), and then transport it to a stirring tank and add process water to prepare an alkyl polyglycoside alkaline aqueous solution with a concentration of about 50%, then adjust the pH to 10-12, maintain the material temperature at about 50-80°C, and add hydrogen peroxide for decolorization. The decolorized alkyl polyglycoside is transported to a precision filter and filtered to obtain a transparent alkyl polyglycoside product.

[0006] However, the existing technology has a high load on the decolorization process, which results in either a dark product color or a large amount of hydrogen peroxide being consumed for decolorization. Summary of the invention

[0007] The present invention aims to solve the problem of high load of the decolorization process in the production of the existing one-step alkyl glycoside surfactant, and provides a new production method of the alkyl glycoside surfactant. The product material obtained by the method has the advantage of low color, thereby reducing the load of the decolorization process in the production of the existing one-step alkyl glycoside surfactant.

[0008] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0009] The production method of an alkyl glycoside surfactant comprises: in the presence of an acidic catalyst and a reaction aid, an alkyl alcohol and a carbohydrate undergo an acetal reaction to obtain a product material containing an alkyl glycoside, wherein the reaction aid molecule has an ethoxylated group, and the ethoxylated group is represented by:

[0010] -(OCH2CH2) m OH;

[0011] Wherein m is the number of OCH2CH2 in the ethoxylated group, and m is greater than 2.

[0012] In the reaction aid, since the ether bond oxygen and the alcohol hydroxyl group co-exist in the ethoxylated group, the color of the product material is significantly reduced.

[0013] For example, but not limited to, m is 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, etc.

[0014] In the above technical solution, the reaction aid preferably conforms to Formula 1:

[0015] R(S1S2S3……S i-1 S i ), formula 1;

[0016] Where R is a carbon-containing group, the number of its remaining valence bonds is i, i is greater than 1; S1, S2, S3, ..., S i-1 and S i is a group attached to the carbon in R, independently H or an ethoxylated group, but not all are H.

[0017] In the above technical solution, the ratio of the carbon number of R to the number of ethoxylated groups is preferably 1 to 20. For example, but not limited to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, etc.

[0018] In the above technical solution, the reaction aid preferably conforms to one of Formula 2, Formula 3 or Formula 4:

[0019] R2-(OCH2CH2) m OH, formula 2;

[0020] wherein R2 is a monovalent hydrocarbon group, such as but not limited to C1-C20 alkyl, more specific non-limiting examples are C1 alkyl, C1 alkyl, C1 alkyl, C1 alkyl, C1 alkyl, C1 alkyl, C1 alkyl, C2 alkyl, C2 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C8 alkyl, C10 alkyl, C12 alkyl, C14 alkyl, C16 alkyl, C18 alkyl and the like; more preferably, m is 4-10, such as but not limited to m is 4, 5, 6, 7, 8, 9, 10 and the like;

[0021] R3(T1T2), formula 3;

[0022] Wherein R3 is a divalent hydrocarbon group, T1 and T2 are ethoxylated groups; for example but not limited to, R3 is an alkylene group, such as ethylene (-CH2CH2-), propylene (-CH2CH2CH2- or -CH(CH3)CH2-), butylene (-CH2CH2CH2CH2-, -CH2CH(CH3)CH2-, -CH(CH2CH3)CH2-, etc.), etc. More preferably, R3 is ethylene or propylene. When R3 is ethylene, the reaction aid shown in Formula 3 is polyethylene glycol, abbreviated as PEG. Preferably, the number average molecular weight of the reaction aid shown in Formula 3 is 200 to 1500, for example but not limited to 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 900, 1000, etc., more preferably 200 to 800, most preferably 300 to 600;

[0023] R4(U1U2U3), formula 4;

[0024] Wherein R4 is a trivalent hydrocarbon group, and U1, U2 and U3 are ethoxylated groups. Non-limiting reaction aids that conform to formula 4 are glycerol ethoxylate or trimethylolpropane ethoxylate. For example, when the reaction aid is glycerol ethoxylate, the number average molecular weight of the glycerol ethoxylate is preferably 500 to 1500, for example but not limited to glycerol ethoxylate number average molecular weight of 550, 600, 650, 700, 750, 800, 900, 1000, 1100, 1200, 1300, 1400, etc.

[0025] The technical key of the present invention is to use a reaction auxiliary in the acetal reaction of an alkyl alcohol and a carbohydrate. There are no special restrictions on other process conditions required for the acetal reaction of an alkyl alcohol and a carbohydrate, as well as the process conditions of the subsequent treatment process of the product material. Those skilled in the art can still adopt those process conditions commonly used in the art.

[0026] The alkyl group in the alkyl alcohol described in the above technical solution is a C8-C18 alkyl group. For example, but not limited to, C8 alkyl, C10 alkyl, C12 alkyl, C14 alkyl, C16 alkyl, C18 alkyl, etc., the corresponding alkyl alcohol is at least one selected from the group consisting of C8 alkyl alcohol, C10 alkyl alcohol, C12 alkyl alcohol, C14 alkyl alcohol, C16 alkyl alcohol and C18 alkyl alcohol. In the varieties of alkyl glycosides actually produced, C12-14 fatty alcohols are the majority of alkyl alcohols, and C12-14 fatty alcohols are mixed alcohols of n-dodecyl alcohol and n-tetradecyl alcohol. The usual ratio of C12-14 fatty alcohols on the market is a weight ratio of C12 alcohol to C14 of 7:3, which is only year-on-year, and this is also the C12-14 fatty alcohol used in the specific implementation of the present invention.

[0027] In the above technical solution, the carbohydrate may be sugar or polysaccharide.

[0028] In the above technical solution, the sugar is preferably glucose.

[0029] In the above technical solution, the polysaccharides are those sugars that can be hydrolyzed into glucose, and more preferably the polysaccharides are starch.

[0030] In the above technical solution, the acidic catalyst is not particularly limited, and those acidic catalysts known in the art can be used. The commonly used acidic catalyst in the art is p-toluenesulfonic acid, and other organic acids or inorganic acids can also be used.

[0031] In the above technical solution, the carbohydrates are calculated based on the glucose structural units contained, and the molar ratio of alkyl alcohol to carbohydrates is preferably 2-6, for example but not limited to, the molar ratio is 2.5, 3, 3.5, 4, 4.5, 5, 5.5 and the like.

[0032] In the above technical solution, the reaction temperature is preferably 105-115°C.

[0033] In the above technical solution, the reaction time is 2 to 6 hours, for example but not limited to 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours and the like.

[0034] Those skilled in the art know that the acetal reaction carried out in the presence of an acidic catalyst is a reversible reaction with water generation, and timely removal of the water generated by the reaction is conducive to the forward reaction. Those skilled in the art know that the water generated by the removal reaction is mainly carried out by reducing the absolute pressure to below the atmospheric pressure or in other words, by a method of evacuating. For example, in order to achieve the purpose of dehydration, the pressure of the reaction can be 3 to 10 kPa in absolute pressure, such as but not limited to 3.5 kPa, 4 kPa, 4.5 kPa, 5 kPa, 5.5 kPa, 6 kPa, 6.5 kPa, 7 kPa, 7.5 kPa, 8 kPa, 8.5 kPa, 9 kPa, 9.5 kPa, etc.

[0035] In the above technical solution, the amount of the acidic catalyst added is 0.5-1.5% of the weight of the carbohydrate, for example but not limited to 0.6%, 0.8%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, etc.

[0036] Although within a certain range, increasing the dosage of the reaction aid will help reduce the color of the product material, when the dosage increases to a certain extent, the contribution of the unit dosage to reducing the color of the product material no longer increases. Taking all factors into consideration, the recommended dosage is that the dosage of the reaction aid is greater than 0 and less than 1% based on the carbohydrate dosage weight, for example but not limited to 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, etc.

[0037] The key to the present invention lies in the acetal reaction step. Those skilled in the art will appreciate that the present invention is also applicable to the steps of the present invention, further comprising a step of neutralizing the product material; or further comprising a step of removing free fatty alcohols; or further comprising a step of decolorizing; or further comprising a step of filtering.

[0038] In the present specification, the color is measured using GB / T 19464-2014.

[0039] The present invention is described in detail below by way of examples and comparative examples. DETAILED DESCRIPTION

[0040] [Comparative Example 1]

[0041] 16200 kg of C12-14 fatty alcohol was added to the glycoside reactor, and the temperature was started to be stirred. When the temperature reached 70°C, 3700 kg of glucose was added and then 43 kg of p-toluenesulfonic acid was added. The circulating stirring was started, and the internal pressure of the reactor was controlled at 4.5 kPa. The temperature of the reactor was increased to 110°C, and the reaction was carried out for 5 hours. After the temperature was lowered to 70°C, the material was transferred to the neutralization reactor, and the pH was neutralized to 9 with a weight concentration of 50% sodium hydroxide aqueous solution (the amount of sodium hydroxide aqueous solution was about 20 kg) to obtain a neutralized material. The neutralized material was sampled and tested for color, and the color was 241 Hazen.

[0042] [Comparative Example 2]

[0043] Add 16,200 kg of C12-14 fatty alcohol and 15 kg of n-butanol to the glycoside reactor, start heating and stirring, when the temperature reaches 70°C, add 3,700 kg of glucose and then add 43 kg of p-toluenesulfonic acid, start circulating stirring, control the internal pressure of the reactor at 4.5 kPa, increase the temperature of the reactor to 110°C, react for 5 hours, cool to 70°C and transfer the material to the neutralization reactor, neutralize with 50% sodium hydroxide aqueous solution by weight to pH 9 (the amount of sodium hydroxide aqueous solution is about 20 kg) to obtain a neutralized material, sample the neutralized material and test the color, the color is 235 Hazen.

[0044] [Comparative Example 3]

[0045] Add 16,200 kg of C12-14 fatty alcohol and 15 kg of ethylene glycol to the glycoside reactor, start heating and stirring, when the temperature reaches 70°C, add 3,700 kg of glucose and then add 43 kg of p-toluenesulfonic acid, start circulating stirring, control the internal pressure of the reactor at 4.5 kPa, increase the temperature of the reactor to 110°C, react for 5 hours, cool to 70°C and transfer the material to the neutralization reactor, neutralize with 50% sodium hydroxide aqueous solution by weight to pH 9 (the amount of sodium hydroxide aqueous solution is about 20 kg) to obtain a neutralized material, sample the neutralized material and test the color, the color is 230 Hazen.

[0046] [Comparative Example 4]

[0047] Add 16,200 kg of C12-14 fatty alcohol and 15 kg of polyethylene glycol dimethyl ether to the glycoside reactor, start heating and stirring, when the temperature reaches 70°C, add 3,700 kg of glucose and then add 43 kg of p-toluenesulfonic acid, start circulating stirring, control the internal pressure of the reactor at 4.5 kPa, increase the temperature of the reactor to 110°C, react for 5 hours, cool to 70°C and transfer the material to the neutralization reactor, neutralize with 50% sodium hydroxide aqueous solution by weight to pH 9 (the amount of sodium hydroxide aqueous solution is about 20 kg) to obtain a neutralized material, sample the neutralized material and test the color, the color is 224 Hazen.

[0048] Polyethylene glycol dimethyl ether is a commonly used desulfurization and decarbonization solvent, also known as NHD solvent. Common specifications include those with a number average molecular weight of 250 and 500. The specification used in Comparative Example 4 is that with a number average molecular weight of 500.

[0049] [Example 1]

[0050] Add 16,200 kg of C12-14 fatty alcohol and 15 kg of triethylene glycol to the glycoside reactor, start heating and stirring, when the temperature reaches 70°C, add 3,700 kg of glucose and then add 43 kg of p-toluenesulfonic acid, start circulating stirring, control the internal pressure of the reactor at 4.5 kPa, increase the temperature of the reactor to 110°C, react for 5 hours, cool to 70°C and transfer the material to the neutralization reactor, neutralize with 50% sodium hydroxide aqueous solution by weight to pH 9 (the amount of sodium hydroxide aqueous solution is about 20 kg) to obtain a neutralized material, sample the neutralized material and test the color, the color is 189 Hazen.

[0051] [Example 2]

[0052] 16,200 kg of C12-14 fatty alcohol and 15 kg of polyethylene glycol (PEG200) were added to the glycoside reactor, and the temperature was started to be stirred. When the temperature reached 70°C, 3,700 kg of glucose was added and then 43 kg of p-toluenesulfonic acid was added. The circulating stirring was started, and the internal pressure of the reactor was controlled at 4.5 kPa. The temperature of the reactor was increased to 110°C, and the reaction was carried out for 5 hours. After the temperature was lowered to 70°C, the material was transferred to the neutralization reactor, and the pH was neutralized to 9 with a weight concentration of 50% sodium hydroxide aqueous solution (the amount of sodium hydroxide aqueous solution was about 20 kg) to obtain a neutralized material. The neutralized material was sampled and tested for color, and the color was 142 Hazen.

[0053] [Example 3]

[0054] 16,200 kg of C12-14 fatty alcohol and 15 kg of polyethylene glycol (PEG300) were added to the glycoside reactor, and the temperature was started to be stirred. When the temperature reached 70°C, 3,700 kg of glucose was added and then 43 kg of p-toluenesulfonic acid was added. The circulating stirring was started, and the internal pressure of the reactor was controlled at 4.5 kPa. The temperature of the reactor was increased to 110°C, and the reaction was carried out for 5 hours. After the temperature was lowered to 70°C, the material was transferred to the neutralization reactor, and the pH was neutralized to 9 with a weight concentration of 50% sodium hydroxide aqueous solution (the amount of sodium hydroxide aqueous solution was about 20 kg) to obtain a neutralized material. The neutralized material was sampled and tested for color, and the color was 97 Hazen.

[0055] [Example 4]

[0056] 16,200 kg of C12-14 fatty alcohol and 15 kg of polyethylene glycol (PEG 400) were added to the glycoside reaction kettle, and the temperature was started to be raised and stirred. When the temperature reached 70°C, 3,700 kg of glucose was added and then 43 kg of p-toluenesulfonic acid was added. The circulating stirring was started, and the internal pressure of the reactor was controlled at 4.5 kPa. The temperature of the reactor was raised to 110°C, and the reaction was carried out for 5 hours. After the temperature was lowered to 70°C, the material was transferred to the neutralization kettle, and the pH was neutralized to 9 with a weight concentration of 50% sodium hydroxide aqueous solution (the amount of sodium hydroxide aqueous solution was about 20 kg) to obtain a neutralized material. The neutralized material was sampled and tested for color, and the color was 83 Hazen.

[0057] [Example 5]

[0058] Add 16,200 kg of C12-14 fatty alcohol and 15 kg of polyethylene glycol (PEG600) to the glycoside reactor, start heating and stirring, when the temperature reaches 70°C, add 3,700 kg of glucose and then add 43 kg of p-toluenesulfonic acid, start circulating stirring, control the internal pressure of the reactor at 4.5 kPa, increase the temperature of the reactor to 110°C, react for 5 hours, cool to 70°C and transfer the material to the neutralization reactor, neutralize with 50% sodium hydroxide aqueous solution by weight to pH 9 (the amount of sodium hydroxide aqueous solution is about 20 kg) to obtain a neutralized material, sample the neutralized material and test the color, the color is 106 Hazen.

[0059] [Example 6]

[0060] Add 16200 kg of C12-14 fatty alcohol and 15 kg of polyethylene glycol (PEG800) to the glycoside reactor, start heating and stirring, when the temperature reaches 70°C, add 3700 kg of glucose and then add 43 kg of p-toluenesulfonic acid, start circulating stirring, control the internal pressure of the reactor at 4.5 kPa, increase the temperature of the reactor to 110°C, react for 5 hours, cool to 70°C and transfer the material to the neutralization reactor, neutralize with 50% sodium hydroxide aqueous solution by weight to pH 9 (the amount of sodium hydroxide aqueous solution is about 20 kg) to obtain a neutralized material, sample the neutralized material and detect the color, the color is 138 Hazen.

[0061] [Example 7]

[0062] Add 16,200 kg of C12-14 fatty alcohol and 15 kg of fatty alcohol polyoxyethylene ether to the glycoside reactor, start heating and stirring, when the temperature reaches 70°C, add 3,700 kg of glucose and then add 43 kg of p-toluenesulfonic acid, start circulating stirring, control the internal pressure of the reactor at 4.5 kPa, increase the temperature of the reactor to 110°C, react for 5 hours, cool to 70°C and transfer the material to the neutralization reactor, neutralize with 50% sodium hydroxide aqueous solution by weight to pH 9 (the amount of sodium hydroxide aqueous solution is about 20 kg) to obtain a neutralized material, sample the neutralized material and detect the color, the color is 173 Hazen.

[0063] The fatty alcohol polyoxyethylene ether used in this embodiment is C12-14 alcohol polyoxyethylene (9) ether, which is a commonly used non-ionic surfactant, referred to as AEO9.

[0064] [Example 8]

[0065] 16,200 kg of C12-14 fatty alcohol and 15 kg of glycerol ethoxylate were added to the glycoside reactor, and the temperature was started to be raised and stirred. When the temperature reached 70°C, 3,700 kg of glucose was added and then 43 kg of p-toluenesulfonic acid was added. The circulating stirring was started, and the internal pressure of the reactor was controlled at 4.5 kPa. The temperature of the reactor was raised to 110°C, and the reaction was carried out for 5 hours. After the temperature was lowered to 70°C, the material was transferred to the neutralization reactor, and the pH was neutralized to 9 with a weight concentration of 50% sodium hydroxide aqueous solution (the amount of sodium hydroxide aqueous solution was about 20 kg) to obtain a neutralized material. The neutralized material was sampled and tested for color, and the color was 169 Hazen.

[0066] Glycerol ethoxylate, also known as polyoxyethylene glycerol ether or glycerol polyoxyethylene ether, can be obtained in varieties with different molecular weights according to the different numbers of ethylene oxide molecules consumed in the ethoxylation reaction of each glycerol molecule. For example, there are varieties such as polyoxyethylene glycerol ether G-12 and G-18 on the market. The number after G represents the number of ethylene oxide molecules consumed by each glycerol molecule in the ethoxylation reaction. Polyoxyethylene glycerol ether G-12 is used in this embodiment.

Claims

1. A method for producing an alkyl polyglycoside surfactant, comprising: In the presence of an acidic catalyst and a reaction aid, an alkyl alcohol and a carbohydrate undergo an acetal reaction to obtain a product material containing an alkyl glycoside, wherein the reaction aid molecule has an ethoxylated group, and the ethoxylated group is represented by: -(OCH2CH2) m OH; wherein m is the number of OCH2CH2 in the ethoxylated group, and m is 2 or more.

2. The production method according to claim 1, characterized in that The reaction aid conforms to Formula 1: R(S1S2S3……S i-1 S i ), formula 1; Where R is a carbon-containing group, the number of its remaining valence bonds is i, i is greater than 1; S1, S2, S3, ..., S i-1 and S i is a group connected to the carbon in R, independently H or ethoxylated groups, but not all H. Preferably, the ratio of the number of carbons in R to the number of ethoxylated groups is 1-20.

3. The production method according to claim 2, characterized in that: The reaction aid conforms to one of Formula 2, Formula 3 or Formula 4: R2-(OCH2CH2) m OH, formula 2; wherein R2 is a monovalent hydrocarbon group (for example but not limited to a C1-C20 alkyl group); more preferably m is 4-10; R3(T1T2), formula 3; wherein R3 is a divalent hydrocarbon group, and T1 and T2 are ethoxylated groups. R4(U1U2U3), formula 4; wherein R4 is a trivalent hydrocarbon group, and U1, U2 and U3 are ethoxylated groups.

4. The production method according to claim 1, characterized in that The alkyl group in the alkyl alcohol is a C8-C18 alkyl group.

5. The production method according to claim 1, characterized in that The carbohydrate is a sugar or a polysaccharide. The sugar is glucose; and / or the polysaccharide is a sugar that can be hydrolyzed into glucose, and more preferably the polysaccharide is starch.

6. The production method according to claim 1, characterized in that The acid catalyst is p-toluenesulfonic acid.

7. The production method according to claim 1, characterized in that The carbohydrates contain glucose structural units, and the feeding molar ratio of alkyl alcohol to carbohydrates is 2-6.

8. The production method according to claim 1, characterized in that The reaction temperature is 105-115°C. And / or the absolute pressure of the reaction is preferably 3-10 kPa. And / or the reaction time is 2-6 hours.

9. The production method according to claim 1, characterized in that The amount of the acid catalyst added is 0.5-1.5% of the weight of the carbohydrate, and / or the amount of the reaction aid added is greater than 0 and less than 1% based on the weight of the carbohydrate.

10. The production method according to claim 1, characterized in that The production method comprises the step of neutralizing the product material, or further comprises the step of removing free fatty alcohol, or further comprises the step of decolorizing, or further comprises the step of filtering.

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