A kind of preparation method of fatty alcohol ether carboxylic acid

Abstract

The invention discloses a method for preparing a fatty alcohol ether carboxylic acid, and belongs to the technical field of synthesis of anionic nonionic-anionic surfactants in organic chemistry. The method uses a fatty alcohol as a raw material, and under the protection of an inert gas, first uses an organic base to react with a fatty alcohol ether to undergo alkalization, and under the action of a phase transfer catalyst, reacts with chloroacetate to undergo carboxymethylation, and obtains a fatty alcohol ether carboxylic acid through acidification and washing. The method for preparing a fatty alcohol ether carboxylic acid of the invention has a simple process, is easy to control in production, has high product purity, and has stable quality.

Description

Technical Field

[0001] The invention belongs to the technical field of synthesis of nonionic-anionic surfactants, and in particular relates to a method for preparing fatty alcohol ether carboxylic acid. Background Art

[0002] Fatty alcohol ether carboxylates are the main varieties of surfactant industry development. They are a kind of multifunctional green surfactants with dual characteristics of nonionic and anionic surfactants. Structurally, it is a polyoxyethylene (EO) with a certain adduct number embedded between the hydrophilic and hydrophobic groups of soap. The introduction of EO chain makes fatty alcohol ether carboxylates have better water solubility, calcium soap dispersibility and hard water resistance. For example, if the lipophilic polyoxypropylene (PO) is added to the polyoxyethylene or hydroxyl part, or the original hydrophilic group is directly blocked with PO, the EO / PO block fatty alcohol ether carboxylates formed are low-foaming surfactants.

[0003] Fatty alcohol ether carboxylates have good compatibility and can be compounded with other types of surfactants. They also have excellent emulsifying properties for oils and fats. They are used as detergents, dispersants, wetting agents, foaming agents, mildness improvers, crude oil demulsifiers, heavy oil viscosity reducers, sewage treatment agents, antistatic agents, emulsifiers, softeners, etc. in the fields of cosmetics, textiles, petroleum, biochemistry, pharmaceuticals, food processing, etc. They are one of the key products for the future development of surfactants.

[0004] At present, the methods used to synthesize alcohol ether carboxylates surfactants from alcohol ethers include oxidation and carboxymethylation. For example, patent application 201810549340.8 discloses a concentration process for preparing fatty alcohol ether carboxylic acid from fatty alcohol ether carboxylates: in an acidification reactor, fatty alcohol ether carboxylates and acid prepared by oxidation are added, and an acidification reaction occurs to generate acid-type fatty alcohol ether carboxylates, and a liquid product is obtained; in a stratification device, the liquid product obtained in the previous step is subjected to static stratification, and the stratified material enters the next step; in a liquid-liquid separation device, the stratified material obtained in the previous step is separated to obtain a lower aqueous phase and an upper material, and the upper material obtained after separation is concentrated to obtain a concentrated material; in a solid-liquid separation device, the concentrated material obtained in the previous step is subjected to solid-liquid separation, and the obtained solid material is used for recovery, and the obtained liquid material is concentrated once as a product. Patent application 201110359285.4 discloses a method for preparing a nonionic-anionic composite surfactant and its application. The nonionic-anionic composite surfactant of the present invention is obtained by adding ethylene oxide to a straight-chain saturated fatty alcohol and then undergoing a carboxymethylation reaction, referred to as alcohol ether carboxylate. The number of carbon atoms in the alkyl group of the fatty alcohol is 12 to 18, and the number of ethylene oxide added n is 2 to 5. By compounding it with a betaine-type amphoteric surfactant, wherein the molar fraction of the alcohol ether carboxylate is 0.10 to 0.50, dissolving it in Daqing Oilfield formation water or simulated formation water, adding 1000 mg / L of polyacrylamide at a total surfactant mass concentration of 0.05% to 0.4%, without adding alkali, at 45°C, the Daqing crude oil / formation water interfacial tension can be reduced to 10 -3 mN / m order of magnitude.

[0005] Among them, the oxidation method has high requirements for equipment, complex process flow, and catalyst recovery problems; the carboxymethylation method has the characteristics of simple equipment and relatively high conversion rate, but there are also many by-products, among which alkaline hydroxide and chloroacetic acid or its salt can easily generate hydroxyacetate. In order to achieve a higher conversion rate, the reaction must be carried out at an increased temperature and reduced pressure, but the temperature cannot be too high, otherwise the by-products will increase. Therefore, it is urgent to improve and provide a stable production process with few by-products and high conversion rate. Summary of the invention

[0006] In order to solve the above problems, the primary purpose of the present invention is to provide a method for preparing fatty alcohol ether carboxylic acid. In the method, under the protection of inert gas, an organic base is first used to react with fatty alcohol ether to cause alkalization reaction, and after the reaction is completed, a carboxymethylation reaction is carried out with chloroacetate, and the fatty alcohol ether carboxylic acid is obtained through acidification and water washing. The process is reasonable, the operation is simple, the conversion rate is improved, the by-products are small, and the production is stable.

[0007] Another object of the present invention is to provide a method for preparing fatty alcohol ether carboxylic acid, which has few by-products and does not require excessive reactants, thus saving raw materials, simplifying complicated operations, and having high product purity.

[0008] The applicant has found that the existing preparation of fatty alcohol ether carboxylic acid is basically obtained by adding ethylene oxide to fatty alcohol, and then undergoing carboxymethylation or catalytic oxidation. Among them, the catalytic oxidation method has high requirements for equipment, complex process flow, and catalyst recovery problems; the carboxymethylation method has the characteristics of simple equipment and relatively high conversion rate, but there are also more by-products. In the control of the reaction process, the addition of chloroacetic acid or its salt and alkali is relatively carried out in several steps, which is relatively cumbersome and requires high control conditions. This is an important reason for the existence of by-products. If the cumbersome steps can be avoided, the generation of by-products will be avoided and the conversion rate will be improved.

[0009] To achieve the above objectives, the technical solution of the present invention is as follows.

[0010] A method for preparing fatty alcohol ether carboxylic acid comprises the following steps: firstly, an organic base is used to react with fatty alcohol ether to cause alkalization reaction under the protection of inert gas; after the reaction, the organic base is used to react with chloroacetate to cause carboxymethylation reaction under the action of a phase transfer catalyst; and the fatty alcohol ether carboxylic acid is obtained through acidification and water washing.

[0011] The invention improves the carboxymethylation reaction, firstly uses an organic base to react with a fatty alcohol ether for alkalization, and then reacts with chloroacetate for carboxymethylation under the action of a catalyst, so that the whole reaction process of the carboxymethylation becomes simple, clear and controllable, thereby avoiding the generation of by-products and improving the conversion rate.

[0012] The molecular formula of the fatty alcohol ether is: RO(CH2CH2O) n [CH2CH(CH3)O] m H

[0013]

[0014] The positions of EO and PO, which are polyoxyethylene and polyoxypropylene, can be inter-adjusted, and n and m are 1-20 and 1-20, respectively.

[0015] The dosage of the fatty alcohol ether, the organic base and the chloroacetate is: fatty alcohol ether: organic base: chloroacetate = 1: 1.1-1.3: 1.1-1.3 (molar ratio).

[0016] The alkalization reaction temperature is 40-60° C., and the reaction time is 1-3 hours.

[0017] The carboxymethylation reaction temperature is 60-100° C., and the reaction time is 4-10 hours.

[0018] The phase transfer catalyst is a quaternary ammonium salt, and the dosage is fatty alcohol ether: phase transfer catalyst = 0.02-0.03 (molar ratio).

[0019] The preparation method of the fatty alcohol ether carboxylic acid of the present invention comprises the following steps: firstly, an organic base is used to react with the fatty alcohol ether to cause an alkalization reaction under the protection of an inert gas, and then, under the action of a phase transfer catalyst, the organic base is used to react with chloroacetate to cause a carboxymethylation reaction, and after the reaction, the fatty alcohol ether carboxylic acid is obtained by acidification and water washing. Such a process has low requirements on equipment and is simple to operate; and the entire reaction process has no redundant process, so that less by-products are produced in the reaction process, the reactants do not need to be excessively excessive, and the product purity is high. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] The method for preparing fatty alcohol ether carboxylic acid achieved by the present invention comprises the following steps:

[0022] S1. Alkalization reaction: Under the protection of inert gas, an organic base is first used to react with the fatty alcohol ether for alkalinization reaction, the reaction temperature is 40-60° C., and the reaction time is 1-3 hours.

[0023] S2, carboxymethylation reaction; after the alkalization reaction is completed, a carboxymethylation reaction is carried out with chloroacetate under the action of a phase transfer catalyst; the carboxymethylation reaction temperature is 60-100°C, and the reaction time is 4-10h.

[0024] The phase transfer catalyst is a quaternary ammonium salt.

[0025] S3, purifying, acidifying and washing with water to obtain fatty alcohol ether carboxylic acid.

[0026] The molecular formula of fatty alcohol ether is: RO(CH2CH2O) n [CH2CH(CH3)O] m H

[0027]

[0028] The positions of polyoxyethylene and polyoxypropylene can be interchanged, n is 1-20, and m is 1-20.

[0029] Fatty alcohol ether: organic base: chloroacetate = 1: 1.1-1.3: 1.1-1.3 (molar ratio).

[0030] Fatty alcohol ether: phase transfer catalyst = 0.02-0.03 (molar ratio).

[0031] The implementation of the present invention is described below in conjunction with embodiments.

[0032] Embodiment 1:

[0033] In a four-necked flask equipped with an electric stirrer, a thermometer and a condenser, add 0.5 mol of fatty alcohol (R is an alkyl group of 12-14, n=1, m=3, and PO is at the end), start stirring, replace the nitrogen three times, add 0.55 mol of sodium tert-butoxide and a phase transfer catalyst in batches, raise the temperature to 40-60°C, and react for 1 hour; then add 0.55 mol of sodium chloroacetate and 0.01 mol of tetrabutylammonium bromide, and react at 95°C for 6 hours. After the reaction is completed, acidify and wash with water to obtain fatty alcohol ether carboxylic acid with a yield of 84%.

[0034] Embodiment 2:

[0035] In a four-necked flask equipped with an electric stirrer, a thermometer and a condenser, add 0.5 mol of fatty alcohol (R is nonyl, n=2, m=2, EO position at the end), start stirring, replace with nitrogen three times, add 0.55 mol of sodium tert-butoxide in batches, raise the temperature to 40-60°C, and react for 2 hours; then add 0.60 mol of sodium chloroacetate and 0.01 mol of tetrabutylammonium bromide, and react at 85°C for 10 hours. After the reaction is completed, acidify and wash with water to obtain fatty alcohol ether carboxylic acid with a yield of 88%.

[0036] Embodiment 3:

[0037] In a four-necked flask equipped with an electric stirrer, a thermometer and a condenser, add 0.5 mol of fatty alcohol (R is decyl, n=3, m=3, EO position at the end), start stirring, replace with nitrogen three times, add 0.60 mol of sodium tert-butoxide in batches, raise the temperature to 40-60°C, and react for 1 hour; then add 0.65 mol of sodium chloroacetate and 0.01 mol of tetrabutylammonium bromide, and react at 70°C for 6 hours. After the reaction is completed, acidify and wash with water to obtain fatty alcohol ether carboxylic acid with a yield of 91%.

[0038] Embodiment 4:

[0039] In a four-necked flask equipped with an electric stirrer, a thermometer and a condenser, add 0.5 mol of fatty alcohol (R is nonyl, n=3, m=2.5, PO position at the end), start stirring, replace the nitrogen three times, add 0.60 mol of sodium tert-butoxide in batches, raise the temperature to 40-60°C, and react for 2 hours; then add 0.60 mol of sodium chloroacetate and 0.013 mol of tetrabutylammonium bromide, and react at 75°C for 6 hours. After the reaction is completed, it is acidified and washed with water to obtain fatty alcohol ether carboxylic acid with a yield of 86%.

[0040] In summary, the preparation method of the fatty alcohol ether carboxylic acid of the present invention has a simple process, easy production control, high product purity and stable quality. The synthesized fatty alcohol ether carboxylic acid has excellent physical and chemical properties and is widely used in household and industrial cleaning, textile, printing and dyeing, leather, chemical fiber and other fields.

[0041] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing fatty alcohol ether carboxylic acid, characterized in that Under the protection of inert gas, an organic base is first used to react with the fatty alcohol ether to undergo alkalization reaction. After the reaction is completed, a carboxymethylation reaction is carried out with chloroacetate under the action of a phase transfer catalyst. The fatty alcohol ether carboxylic acid is obtained after acidification and water washing. The molecular formula of the fatty alcohol ether is: RO(CH2CH2O) n [CH2CH(CH3)O] m H, The positions of polyoxyethylene and polyoxypropylene can be interchanged, n is 1-20, and m is 1-20.

2. The method for preparing fatty alcohol ether carboxylic acid according to claim 1, characterized in that In terms of molar ratio, the amount of fatty alcohol ether, organic base and chloroacetate is fatty alcohol ether: organic base: chloroacetate = 1: 1.1-1.3: 1.1-1.

3.

3. The method for preparing fatty alcohol ether carboxylic acid according to claim 1, characterized in that The alkalization reaction temperature is 40-60° C., and the reaction time is 1-3 hours.

4. The method for preparing fatty alcohol ether carboxylic acid according to claim 1, characterized in that The carboxymethylation reaction temperature is 60-100° C., and the reaction time is 4-10 hours.

5. The method for preparing fatty alcohol ether carboxylic acid according to claim 1, characterized in that The phase transfer catalyst is a quaternary ammonium salt, and the molar ratio of the usage is fatty alcohol ether: phase transfer catalyst = 0.02-0.03.

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