A process for the synthesis of cocoyl ethanolamide

Abstract

The application relates to the technical field of surfactant synthesis, and discloses a synthesis process of cocoyl ethanolamine, which adopts a specific catalyst and comprises the following steps: S1, adding coconut oil fatty acid and methyl monoethanolamine into a reactor according to a certain feeding ratio, and then adding sodium hydroxide and a catalyst into the reactor; S2, reacting under specific reaction conditions under the protection of nitrogen to obtain a reaction mixture; S3, adding diethyl ether and deionized water into the reaction mixture, taking the oil phase after static stratification, distilling and recovering the diethyl ether, and preparing a cocoyl ethanolamine crude product; and S4, purifying and treating the cocoyl ethanolamine crude product prepared in the step S3 to prepare a cocoyl ethanolamine pure product. The specific composite catalyst is adopted, the reaction conversion rate is high, the prepared product is high in purity, the catalyst can be recycled and reused, and the synthesis cost is low.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of surfactant synthesis, in particular to a synthesis process of cocoyl ethanolamine. BACKGROUND

[0002] Cocoyl ethanolamine, also known as cocoyl monoethanolamine, is a new type of non-ionic surfactant. The performance of cocoyl ethanolamine is similar to that of cocoyl diethanolamine, but the safety problem of free diethanolamine in cocoyl diethanolamine, which is easy to be nitrosylated to form strong carcinogenic nitrosamine, is eliminated. In addition, cocoyl ethanolamine has good thickening, foaming, stable foam, anti-rust, anti-static and excellent calcium soap dispersing ability and detergency, and has the advantages of low toxicity, high biodegradability, etc. Especially its unique thickening property and softness make it widely used in the formulation of various detergents and cosmetics.

[0003] At present, there are three main synthesis processes of cocoyl ethanolamine: the first one is to directly react coconut oil with monoethanolamine, but the reaction is not easy to complete, and the product contains glycerol and a large amount of free monoethanolamine; the second one is to synthesize by coconut oil fatty acid and monoethanolamine, but the reaction temperature is high, the color of the product is easy to change, and amine ester and other by-products are produced; the third one is to synthesize by reacting methyl ester of coconut oil with monoethanolamine, but this process requires the use of a specific catalyst, the synthesis cost is high, and there are dangerous factors such as methanol treatment.

[0004] Therefore, there is an urgent need in the art to design a cocoyl ethanolamine synthesis process with relatively low cost, high reaction conversion rate and good process safety. SUMMARY

[0005] In order to solve at least one of the above technical problems, a synthesis process with high reaction conversion rate, relatively low process cost and high product purity is developed, and the present application provides a synthesis process of cocoyl ethanolamine.

[0006] The present application provides a synthesis process of cocoyl ethanolamine, comprising the following steps:

[0007] S1, coconut oil fatty acid and methyl monoethanolamine are added to the reactor in a molar ratio of 1:1.1-1.5, and then sodium hydroxide and a catalyst are added to the reactor to complete the preparation of the reaction solution;

[0008] S2, the reaction solution prepared in step S1 is stirred at 90-120℃ under nitrogen protection for 3.5-5.5h to obtain a reaction mixture;

[0009] S3, adding ethyl ether and deionized water to the reaction mixture obtained in step S2, and separating the layers after standing, and taking the oil phase, and distilling to recover the ethyl ether, to obtain a crude cocoyl ethanolamine product;

[0010] S4, purifying the crude cocoyl ethanolamine product obtained in step S3, to obtain a cocoyl ethanolamine product.

[0011] The catalyst comprises porous silica gel particles loaded with vanadium pentoxide and ZSM-5 molecular sieves loaded with aluminum oxide.

[0012] Optionally, in step S1, the coconut oil fatty acid and the methyl monoethanolamine are added in a molar ratio of 1:1.15-1.20.

[0013] Optionally, in step S1, the sodium hydroxide is added in a molar ratio of 0.4-0.6:1 of sodium hydroxide to coconut oil fatty acid.

[0014] Optionally, in step S1, the catalyst is added in an amount of 1-2% of the total mass of the coconut oil fatty acid and the monoethanolamine.

[0015] Optionally, in step S2, the reaction temperature is 95-100°C.

[0016] Optionally, in step S2, the reaction vacuum degree is 80-85 kPa.

[0017] Optionally, in step S2, the stirring speed is 400-600 rpm.

[0018] Optionally, in step S4, the purification process comprises the following steps:

[0019] S4-1, preparing an acetic acid solution with a concentration of 30-35% by taking acetic acid in an amount corresponding to a molar ratio of 1:1.05-1.1 of the excess part of the monoethanolamine to acetic acid;

[0020] S4-2, mixing the acetic acid solution prepared in step S4-1 with the crude cocoyl ethanolamine product, and stirring for more than 30 min, and taking the oil phase after standing and separating the layers;

[0021] S4-3, distilling the oil phase obtained in step S4-2 to remove light components, to obtain a cocoyl ethanolamine product.

[0022] Optionally, the catalyst further comprises an activated carbon catalyst loaded with a ruthenium compound.

[0023] Further optionally, the catalyst is prepared in a molar ratio of 4:1-2:1-2 of vanadium element, aluminum element, and ruthenium element.

[0024] To sum up, the present application comprises at least one of the following beneficial technical effects:

[0025] 1. The present application designs a synthesis process of cocoyl ethanolamine, which can effectively reduce the reaction temperature, improve the reaction safety, and effectively improve the reaction conversion rate by using a specific catalyst. In addition, the catalyst of the present application can be recycled, which can effectively reduce the synthesis cost.

[0026] 2. The synthesis process of cocoyl ethanolamine designed by the present application uses specific process steps and process conditions to obtain cocoyl ethanolamine with high purity, very low free ethanolamine content, and relatively better color and quality. DETAILED DESCRIPTION

[0027] The present application is further described in detail below in combination with examples.

[0028] The present application designs a synthesis process of cocoyl ethanolamine, which comprises the following steps:

[0029] S1, coconut oil fatty acid and methyl monoethanolamine are added to the reactor in a molar ratio of 1:1.1-1.5, and then sodium hydroxide and a catalyst are added to the reactor to complete the reaction liquid preparation;

[0030] S2, the reaction liquid prepared in step S1 is stirred at 90-120℃ under nitrogen protection for 3.5-5.5h to obtain a reaction mixture;

[0031] S3, adding diethyl ether and deionized water to the reaction mixture obtained in step S2, after standing and layering, taking the oil phase, distilling and recovering the diethyl ether to obtain a crude cocoyl ethanolamine product;

[0032] S4, purifying the crude cocoyl ethanolamine product prepared in step S3 to obtain a pure cocoyl ethanolamine product;

[0033] The catalyst comprises porous silica gel particles loaded with vanadium pentoxide and alumina modified ZSM-5 molecular sieve.

[0034] In the prior art, the synthesis process of cocoyl ethanolamine synthesized by using coconut oil fatty acid and monoethanolamine has a relatively high reaction temperature, and there are problems such as deepening of the color of the synthesized cocoyl ethanolamine and relatively low purity. In the prior art, a complex purification and treatment process is usually required to solve the above problems. This results in high synthesis cost, relatively low synthesis efficiency, and insufficient synthesis yield.

[0035] The present application effectively reduces the reaction conditions, improves the reaction conversion rate, and effectively reduces the occurrence rate of side reactions by designing a specific composite catalyst, thereby solving many problems existing in the prior art.

[0036] The following is an embodiment of the present application.

[0037] The main raw materials used in the embodiments of the present application are derived from commercial purchase.

[0038] Among them, the porous silica gel particles loaded with vanadium pentoxide are purchased from Shaanxi Kaidahua Chemical Co., Ltd.; the ZSM-5 molecular sieve loaded with alumina is purchased from Beijing Bailingwei Technology Co., Ltd.; the activated carbon catalyst loaded with ruthenium compounds is purchased from Shaanxi Kaidahua Chemical Co., Ltd.; the coconut oil fatty acid is purchased from Guangzhou Gongsin Chemical Co., Ltd., with a purity of more than 99%; the monoethanolamine is purchased from Shandong Kejian Chemical Co., Ltd., with a purity of more than 99%.

[0039] Example One

[0040] The synthesis process of the coconut oil fatty acid monoethanolamine of the present embodiment comprises the following steps:

[0041] S1, coconut oil fatty acid and methyl monoethanolamine are added to the reactor according to a molar ratio of 1:1.1, and then sodium hydroxide and a catalyst are added to the reactor to complete the preparation of the reaction solution; sodium hydroxide is added according to a molar ratio of sodium hydroxide to coconut oil fatty acid of 0.4:1; the catalyst is a composite catalyst of porous silica gel particles loaded with vanadium pentoxide and ZSM-5 molecular sieve loaded with alumina, which is prepared according to a molar ratio of vanadium element to aluminum element of 4:1, and the amount of catalyst added is 1% of the total mass of vanadium pentoxide and alumina in the composite catalyst based on the total mass of coconut oil fatty acid and monoethanolamine;

[0042] S2, the reaction solution prepared in step S1 is stirred at a temperature of 90°C for 5.5h under the protection of nitrogen; magnetic stirring is used to control the stirring speed at 300rpm;

[0043] S3, ethyl ether and deionized water are added to the reaction mixture obtained in step S2, and after standing and layering, the oil phase is taken and the ethyl ether is recovered by distillation to prepare the crude coconut oil fatty acid monoethanolamine;

[0044] S4, the crude coconut oil fatty acid monoethanolamine prepared in step S3 is purified by distillation to remove light components to obtain the pure coconut oil fatty acid monoethanolamine.

[0045] Example Two

[0046] The synthesis process of the coconut oil fatty acid monoethanolamine of the present embodiment comprises the following steps:

[0047] S1, coconut oil fatty acid and methyl monoethanolamine are added into a reactor according to a molar ratio of 1:1.5, and then sodium hydroxide and a catalyst are added into the reactor to complete the preparation of the reaction solution; the sodium hydroxide is added according to a molar ratio of sodium hydroxide to coconut oil fatty acid of 0.6:1; the catalyst is a composite catalyst of porous silica gel particles loaded with vanadium pentoxide and ZSM-5 molecular sieve loaded with aluminum oxide, which is prepared according to a molar ratio of vanadium element to aluminum element of 4:1, and the amount of the catalyst added is 1% of the total mass of vanadium pentoxide and aluminum oxide in the composite catalyst, based on the total mass of coconut oil fatty acid and monoethanolamine;

[0048] S2, the reaction solution prepared in step S1 is stirred at 120°C for 3.5h under nitrogen protection to obtain a reaction mixture; magnetic stirring is used, and the stirring speed is controlled at 300rpm;

[0049] S3, ethyl ether and deionized water are added to the reaction mixture obtained in step S2, and after standing and layering, the oil phase is taken, and the ethyl ether is recovered by distillation to obtain a crude cocoyl ethanolamine product;

[0050] S4, the crude cocoyl ethanolamine product prepared in step S3 is purified by distillation to remove light components to obtain a pure cocoyl ethanolamine product.

[0051] Example Three

[0052] The synthesis process of cocoyl ethanolamine in this example includes the following steps:

[0053] S1, coconut oil fatty acid and methyl monoethanolamine are added into a reactor according to a molar ratio of 1:1.15, and then sodium hydroxide and a catalyst are added into the reactor to complete the preparation of the reaction solution; the sodium hydroxide is added according to a molar ratio of sodium hydroxide to coconut oil fatty acid of 0.5:1; the catalyst is a composite catalyst of porous silica gel particles loaded with vanadium pentoxide and ZSM-5 molecular sieve loaded with aluminum oxide, which is prepared according to a molar ratio of vanadium element to aluminum element of 4:2, and the amount of the catalyst added is 2% of the total mass of vanadium pentoxide and aluminum oxide in the composite catalyst, based on the total mass of coconut oil fatty acid and monoethanolamine;

[0054] S2, the reaction solution prepared in step S1 is stirred at 95°C for 4.5h under nitrogen protection to obtain a reaction mixture; magnetic stirring is used, and the stirring speed is controlled at 400rpm;

[0055] S3, ethyl ether and deionized water are added to the reaction mixture obtained in step S2, and after standing and layering, the oil phase is taken, and the ethyl ether is recovered by distillation to obtain a crude cocoyl ethanolamine product;

[0056] S4, the crude product of cocoyl ethanolamine prepared in step S3 is purified by distillation to remove light components to obtain a pure product of cocoyl ethanolamine.

[0057] Example Four

[0058] The synthesis process of cocoyl ethanolamine in this example comprises the following steps:

[0059] S1, coconut oil fatty acid and methyl monoethanolamine are added into a reactor according to a molar ratio of 1:1.20, and then sodium hydroxide and a catalyst are added into the reactor to complete the preparation of the reaction solution; the sodium hydroxide is added according to a molar ratio of sodium hydroxide to coconut oil fatty acid of 0.5:1; the catalyst is a composite catalyst of porous silica gel particles loaded with vanadium pentoxide and ZSM-5 molecular sieve loaded with aluminum oxide, which is prepared according to a molar ratio of vanadium element to aluminum element of 4:2, and the amount of the catalyst added is 2% of the total mass of vanadium pentoxide and aluminum oxide in the composite catalyst, based on the total mass of coconut oil fatty acid and monoethanolamine;

[0060] S2, the reaction solution prepared in step S1 is stirred at a temperature of 100°C for 4.0h under nitrogen protection to obtain a reaction mixture; magnetic stirring is used to control the stirring speed at 600rpm;

[0061] S3, ethyl ether and deionized water are added to the reaction mixture obtained in step S2, and after standing and layering, the oil phase is taken and the ethyl ether is recovered by distillation to obtain a crude product of cocoyl ethanolamine;

[0062] S4, the crude product of cocoyl ethanolamine prepared in step S3 is purified by distillation to remove light components to obtain a pure product of cocoyl ethanolamine.

[0063] Example Five

[0064] The difference between this example and Example Four is that in step S2, the vacuum degree of the reaction is controlled at 80-85kPa.

[0065] Example Six

[0066] The difference between this example and Example Five is that in step S2, magnetic stirring is used to control the stirring speed at 550rpm.

[0067] Example Seven

[0068] The difference between this example and Example Six is that in step S4, the purification process uses the following steps:

[0069] S4-1, acetic acid is taken according to a molar ratio of the excess part of monoethanolamine to acetic acid of 1:1.05 to prepare an acetic acid solution with a concentration of 35%;

[0070] S4-2, the acetic acid solution configured in step S4-1 is mixed with the crude cocoyl ethanolamine, and stirred for 30 min, and after standing and layering, the oil phase is taken;

[0071] S4-3, the oil phase obtained in step S4-2 is subjected to distillation treatment to remove light components, to obtain pure cocoyl ethanolamine.

[0072] Example Eight

[0073] The difference between this example and example six is that in step S4, the purification treatment adopts the following steps:

[0074] S4-1, acetic acid is taken according to a molar ratio of excess part of monoethanolamine to acetic acid of 1:1.1, and is configured into an acetic acid solution with a concentration of 30%;

[0075] S4-2, the acetic acid solution configured in step S4-1 is mixed with the crude cocoyl ethanolamine, and stirred for 30 min, and after standing and layering, the oil phase is taken;

[0076] S4-3, the oil phase obtained in step S4-2 is subjected to distillation treatment to remove light components, to obtain pure cocoyl ethanolamine.

[0077] Example Nine

[0078] The difference between this example and example eight is that in step S1, the catalyst is a composite catalyst composed of porous silica gel particles loaded with vanadium pentoxide, ZSM-5 molecular sieve loaded with aluminum oxide, and activated carbon catalyst loaded with ruthenium compound, configured according to a molar ratio of vanadium element, aluminum element and ruthenium element of 4:2:1, and the addition amount of catalyst is 2% of the total mass of coconut oil fatty acid and monoethanolamine based on the total mass of vanadium pentoxide, aluminum oxide and ruthenium compound in the composite catalyst.

[0079] Example Ten

[0080] The difference between this example and example eight is that in step S1, the catalyst is a composite catalyst composed of porous silica gel particles loaded with vanadium pentoxide, ZSM-5 molecular sieve loaded with aluminum oxide, and activated carbon catalyst loaded with ruthenium compound, configured according to a molar ratio of vanadium element, aluminum element and ruthenium element of 4:2:2, and the addition amount of catalyst is 2% of the total mass of coconut oil fatty acid and monoethanolamine based on the total mass of vanadium pentoxide, aluminum oxide and ruthenium compound in the composite catalyst.

[0081] Comparative Example One

[0082] The difference between the comparative example one of the present application and example two is that sodium hydroxide is added according to a molar ratio of sodium hydroxide to coconut oil fatty acid of 0.8:1, and no catalyst of the present application is added.

[0083] Comparative Example Two

[0084] The synthesis process of the cocoyl ethanolamine of the present comparative example comprises the following steps:

[0085] S1, coconut oil fatty acid and methyl monoethanolamine are added into a reactor according to a molar ratio of 1:1.35, and then sodium hydroxide and vanadium pentoxide catalyst are added into the reactor to complete the preparation of the reaction solution; the sodium hydroxide is added according to a molar ratio of sodium hydroxide to coconut oil fatty acid of 0.8:1; the vanadium pentoxide is added according to 2% of the total mass of the coconut oil fatty acid and monoethanolamine.

[0086] S2, the reaction solution prepared in step S1 is stirred at a temperature of 150°C for 5h under nitrogen protection to obtain a reaction mixture;

[0087] S3, ether and deionized water are added to the reaction mixture obtained in step S2, and after standing and layering, the oil phase is taken, and the ether is recovered by distillation to obtain a crude cocoyl ethanolamine product;

[0088] S4, the crude cocoyl ethanolamine product prepared in step S3 is purified according to a molecular distillation purification process to obtain a pure cocoyl ethanolamine product.

[0089] Detection:

[0090] The purity and color of the cocoyl ethanolamine products prepared in Examples 1 to 10 and Comparative Examples 1 to 2 of the present application are detected, and the yield is calculated based on the coconut oil fatty acid. The test results are shown in Table 1.

[0091] Table 1 Test results of Examples 1 to 10 and Comparative Examples 1 to 2

[0092] Purity (%) Yield (%) Color Example 1 93.92 93.81 Normal Example 2 92.64 94.02 Normal Example 3 94.18 94.36 Normal Example 4 94.24 94.39 Normal Example 5 94.79 95.76 Normal Example 6 94.76 95.78 Normal Example 7 98.79 95.66 Normal Example 8 98.81 95.64 Normal Example 9 99.18 96.41 Normal Example 10 99.12 96.38 Normal Comparative Example 1 82.28 80.64 Dark Comparative Example 2 86.33 83.19 Slightly Dark

[0093] As can be seen from the data in Table 1, the cocoyl ethanolamine prepared in Examples 1 to 6 of the present application has a purity and yield that are much better than the products prepared in Comparative Examples 1 to 2 after only using simple distillation purification, and the color and quality are relatively better; and after using acid washing and distillation purification steps in Examples 7 to 8 of the present application, the purity of the product is greatly improved, and the yield is slightly reduced; and after using the optimized composite catalyst in Examples 9 to 10 of the present application, the purity and yield of the product are further improved.

[0094] It can be seen that the specific composite catalyst used in the present application can effectively improve the reaction conversion rate and greatly reduce the occurrence of side reactions, and the cocoyl ethanolamine prepared has a relatively better purity and a relatively higher yield. The composite catalyst of the present application uses a specific solid supported catalyst, which can be recovered by filtration, and can be reused after vacuum heating purification to remove the adsorbed organic impurities, which can effectively reduce the synthesis cost.

[0095] In addition, through the data comparison of the first to tenth embodiments of the present application, it can be seen that the present application can further improve the reaction conversion rate after optimizing the process parameters, especially using a specific reaction vacuum.

[0096] The above are preferred embodiments of the present application, and do not limit the protection scope of the present application, so: all equivalent changes made in the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A process for synthesizing cocoyl ethanolamine, characterized in that, Includes the following steps: S1. Add coconut oil fatty acids and methyl monoethanolamine to the reactor at a molar ratio of 1:1.1~1.5, then add sodium hydroxide and catalyst to the reactor to complete the preparation of the reaction solution; add sodium hydroxide at a molar ratio of sodium hydroxide to coconut oil fatty acids of 0.4~0.6:

1. S2. The reaction solution prepared in step S1 is stirred and reacted under nitrogen protection at a temperature of 90~120℃ for 3.5~5.5h to obtain a reaction mixture. S3. Add diethyl ether and deionized water to the reaction mixture obtained in step S2, let it stand and separate into layers, take the oil phase, and distill to recover the diethyl ether to obtain crude cocoyl ethanolamine. S4. Purify the crude cocoyl ethanolamine obtained in step S3 to obtain pure cocoyl ethanolamine. The catalyst is a porous silica gel particle loaded with vanadium pentoxide and a ZSM-5 molecular sieve loaded with alumina.

2. The synthesis process of cocoyl ethanolamine according to claim 1, characterized in that, In step S1, coconut oil fatty acids and methyl monoethanolamine are fed in a molar ratio of 1:1.15~1.

20.

3. The synthesis process of cocoyl ethanolamine according to claim 1, characterized in that, In step S1, the catalyst is added at a ratio of 1-2% of the total mass of coconut oil fatty acids and monoethanolamine.

4. The synthesis process of cocoyl ethanolamine according to claim 1, characterized in that, In step S2, the reaction temperature is 95~100℃.

5. The synthesis process of cocoyl ethanolamine according to claim 1, characterized in that, In step S2, the reaction vacuum degree is 80~85kPa.

6. The synthesis process of cocoyl ethanolamine according to claim 1, characterized in that, In step S2, the stirring speed is 400~600 rpm.

7. The synthesis process of cocoyl ethanolamine according to claim 1, characterized in that, In step S4, the purification process includes the following steps: S4-1. Measure acetic acid according to the molar ratio of excess monoethanolamine to acetic acid of 1:1.05~1.1, and prepare an acetic acid solution with a concentration of 30~35%. S4-2. Mix the acetic acid solution prepared in step S4-1 with the crude cocoyl ethanolamine, stir for more than 30 minutes, let stand for separation, and then take the oil phase. S4-3. The oil phase obtained in step S4-2 is distilled to remove light components, and pure cocoyl ethanolamine is obtained.

8. The synthesis process of cocoyl ethanolamine according to claim 1, characterized in that, The catalyst also includes an activated carbon catalyst supported on ruthenium compounds.

9. The synthesis process of cocoyl ethanolamine according to claim 8, characterized in that, The catalyst is configured with vanadium, aluminum and ruthenium in a molar ratio of 4:1~2:1~2.