Process for the preparation of fatty acid polyoxyethylene esters

Abstract

The application belongs to the technical field of organic compound synthesis, and discloses a preparation method of fatty acid polyoxyethylene ester. The preparation method is as follows: fatty acid is mixed with a catalyst, nitrogen is placed, dehydration is performed, and then one-time temperature rising is performed; then first ethylene oxide is added dropwise to perform pre-reaction and ripening; after two-time temperature rising, second ethylene oxide is added dropwise to perform polymerization reaction, and after the dropwise addition is completed, two-time ripening is performed; finally, degassing and neutralization are performed to obtain the product. By controlling the molar number of ethylene oxide in the chain initiation stage and the reaction temperature, the fatty acid can be completely converted into fatty acid glycol ester, and then the fatty acid glycol ester is reacted with ethylene oxide to obtain the fatty acid polyoxyethylene ester; and in the ripening stage, the reaction temperature is first reduced and then ripening is performed, which can effectively prevent the ester exchange reaction. The fatty acid polyoxyethylene ester prepared by the application has low EO and dioxane contents, and the PEG content is less than 20%.

Description

Technical Field

[0001] This invention belongs to the field of organic compound synthesis technology, and specifically relates to a method for preparing fatty acid polyoxyethylene ester. Background Technology

[0002] Fatty acid polyoxyethylene esters are among the most widely used nonionic surfactants, finding broad applications in the pharmaceutical, textile, leather, cosmetic, food, and rubber industries. Their applications vary depending on the type of fatty acid. Lauric acid polyoxyethylene esters (LAE series) possess excellent detergency, smoothing, and emulsifying properties and are commonly used as oiling agents for synthetic fibers. Stearic acid polyoxyethylene esters (SG series) are commonly used as emulsifiers, thickeners, and pearlescent agents in cosmetics and dyes, and can also be used as softeners and antistatic agents in the textile industry. Oleic acid polyoxyethylene esters (OE series) can be used as lubricants in metal cutting and forming processes, and so on.

[0003] Industrially, the synthesis routes for fatty acid polyoxyethylene esters commonly employ esterification and ethoxylation. Esterification involves high reaction temperatures, high energy consumption, and low purity of the finished product, with free acid content reaching up to 10% wt. Ethoxylation is generally a one-step process, characterized by a mature process route, easily identifiable reaction endpoints, and low free acid content in the prepared product, resulting in stable quality. However, products prepared using this method have high EO and dioxane content, and polyethylene glycol content reaching 25% or higher, failing to meet application requirements. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a method for preparing fatty acid polyoxyethylene esters. The fatty acid polyoxyethylene esters prepared by the present invention have low EO and dioxane contents.

[0005] This invention provides a method for preparing fatty acid polyoxyethylene ester.

[0006] Specifically, a method for preparing a fatty acid polyoxyethylene ester includes the following steps:

[0007] The fatty acid was mixed with the catalyst, and after being placed in nitrogen and dehydrated, it was heated once. Then, the first ethylene oxide was added dropwise for pre-reaction and ripening. After a second heating, the second ethylene oxide was added dropwise for polymerization. After the addition was completed, it was ripened a second time. Finally, after degassing and neutralization, fatty acid polyoxyethylene ester was obtained.

[0008] The molar ratio of the fatty acid to the first ethylene oxide is 1:0.8 to 2.2;

[0009] The preferred molar ratio of the fatty acid to the second ethylene oxide is 1:4 to 100;

[0010] The temperature after the first heating is 90–120°C;

[0011] The temperature after the second heating is 5 to 75°C higher than the temperature after the first heating.

[0012] In some embodiments of the present invention, the fatty acids include at least one fatty acid selected from saturated fatty acids and unsaturated fatty acids having 4 to 22 carbon atoms. For example, the C8 fatty acid can be 2-ethyl-1-hexanoic acid (CAS: 149-57-5), or octanoic acid (CAS: 124-07-2), or a mixture of fatty acids with C8 as the main component; the C12 fatty acid can be lauric acid (CAS: 143-07-7), or a mixture of fatty acids with C12 as the main component; the C14 fatty acid can be palmitic acid (CAS: 57-10-3), or a mixture of fatty acids with C14 as the main component; the C18 fatty acid can be stearic acid (CAS: 57-11-4), or oleic acid (CAS: 112-80-1), or a mixture of fatty acids with C18 as the main component, etc. The C4 to C22 fatty acids also include mixtures of any two or more compounds of C4 to C22 fatty acids in any proportion. In some embodiments of the present invention, the fatty acid includes at least one selected from 2-methyl-1-hexanoic acid, lauric acid, palmitic acid, stearic acid, palmitoleic acid, and oleic acid.

[0013] In some embodiments of the present invention, the catalyst includes at least one selected from Na, K, CH3OK, CH3ONa, KOH, and NaOH.

[0014] In some embodiments of the present invention, the amount of catalyst added is 0.03% to 0.5% of the total mass of fatty acid polyoxyethylene esters. Preferably, the amount of catalyst added is 0.04% to 0.2% of the total mass of fatty acid polyoxyethylene esters.

[0015] In some embodiments of the present invention, the molar ratio of the fatty acid to the first ethylene oxide is 1:1 to 2.

[0016] In some embodiments of the present invention, the molar ratio of the fatty acid to the second ethylene oxide is preferably 1:5 to 100.

[0017] In some embodiments of the present invention, the temperature after the first heating is 110-120°C.

[0018] In some embodiments of the present invention, the temperature after the second heating is 5 to 50°C higher than the temperature after the first heating, such as 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 45°C, or 50°C.

[0019] In some embodiments of the present invention, a cooling process is performed before the secondary curing, wherein the cooling process involves lowering the temperature to 10-30°C below the temperature after the secondary heating. In some embodiments of the present invention, the cooling process involves lowering the temperature to 15-25°C below the temperature after the secondary heating. By lowering the reaction temperature before curing in the curing stage, the present invention can effectively prevent the transesterification reaction from proceeding, thereby further reducing the PEG content.

[0020] In some embodiments of the present invention, the temperature of nitrogen application is 20-50°C, and the number of nitrogen applications is 1-4.

[0021] In some embodiments of the present invention, the dehydration temperature is 60–120°C, and the dehydration time is 30–90 min.

[0022] In some embodiments of the present invention, the rate of adding the first ethylene oxide is 1 to 15 g / min; the rate of adding the second ethylene oxide is 1 to 15 g / min.

[0023] In some embodiments of the present invention, the pressure of the pre-reaction is 0 to 0.5 MPa; the pressure of the polymerization reaction is 0 to 0.5 MPa.

[0024] In some embodiments of the present invention, the degassing temperature is 60-120°C and the degassing time is 5-30 minutes.

[0025] Because fatty acids are acidic, ethylene oxide readily reacts with another molecule of ethylene oxide to form dioxane during the chain initiation stage at high temperatures. This invention, by first adding a portion of ethylene oxide and controlling the molar amount of ethylene oxide and the reaction temperature during the chain initiation stage, enables the complete conversion of fatty acids into fatty acid glycol esters, reducing and avoiding the formation of dioxane. After pre-reaction, the system is converted from acidic to alkaline before reacting with ethylene oxide to form fatty acid polyoxyethylene esters. Furthermore, after the addition of ethylene oxide, the reaction temperature is lowered before aging to prevent transesterification, thereby reducing the PEG content. The preparation method provided by this invention can effectively reduce the content of EO, dioxane, and PEG in the product.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] The method for preparing fatty acid polyoxyethylene esters provided by this invention, by controlling the molar amount of ethylene oxide and the reaction temperature during the chain initiation stage, enables the complete conversion of fatty acids into fatty acid glycol esters, transforming the system from acidic to alkaline, before reacting with ethylene oxide to generate fatty acid polyoxyethylene esters. The fatty acid polyoxyethylene esters prepared by this invention have low EO and dioxane content and a PEG content of less than 20%. Detailed Implementation

[0028] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0029] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0030] Example 1-1

[0031] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0032] First, add 288g of 2-ethyl-1-hexanoic acid and 1.1g of [unclear text - possibly a specific ingredient or compound] to a 2.5L high-pressure reactor. Using KOH catalyst in a sealed reactor, the stirring was started and a vacuum was drawn. The gas inside the reactor was then replaced with nitrogen three times. The temperature was raised to 100℃ for dehydration. After dehydration, the temperature was raised to 115-120℃, and 88g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 5g / min. The reaction temperature was controlled at 115-120℃, and the reaction pressure was kept below 0.5MPa. After the addition was complete, the reactor was allowed to mature until the pressure no longer dropped. Then, the temperature was raised to 140℃, and 712g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 10g / min. The reaction temperature was controlled at 140-145℃, and the reaction pressure was kept below 0.5MPa. After the addition was complete, the temperature was lowered to 120℃ for a second maturation. The second maturation was allowed to continue until the pressure no longer dropped. The reactor was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80℃, and 1.1g of glacial acetic acid was added for neutralization to obtain isooctanoic acid polyoxyethylene ester 400.

[0033] Examples 1-2

[0034] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0035] First, add 288g of 2-ethyl-1-hexanoic acid and 1.1g of [unclear text - possibly a specific ingredient or compound] to a 2.5L high-pressure reactor. Using KOH catalyst in a sealed reactor, the stirring was started and a vacuum was applied. The gas inside the reactor was then replaced three times with nitrogen. The temperature was raised to 100℃ for dehydration. After dehydration, the temperature was raised to 115-120℃, and 88g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 5g / min. The reaction temperature was controlled at 115-120℃, and the reaction pressure was kept below 0.5MPa. After the addition was complete, the reactor was allowed to mature until the pressure did not drop. Then, the temperature was raised to 140℃, and 712g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 10g / min. The reaction temperature was controlled at 140-145℃, and the reaction pressure was kept below 0.5MPa. After the addition was complete, the reactor was allowed to mature again until the pressure did not drop. The reactor was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80℃, and 1.1g of glacial acetic acid was added for neutralization to obtain isooctanoic acid polyoxyethylene ester 400.

[0036] Comparative Example 1

[0037] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0038] First, 288g of 2-ethyl-1-hexanoic acid and 1.1g of KOH catalyst were added to a 2.5L high-pressure reactor. The reactor was sealed, stirring was started, and a vacuum was drawn. Then, the gas inside the reactor was replaced with nitrogen three times. The temperature was raised to 100℃ for dehydration. After dehydration, the temperature was raised to 140℃, and 800g of ethylene oxide was added dropwise at a rate of 10g / min. The reaction temperature was controlled between 140℃ and 145℃, and the reaction pressure was kept below 0.5MPa. After the addition was complete, a second ripening was carried out until the pressure no longer dropped. Degassing (pressure less than -0.098MPa) was performed for 10min. After degassing, the temperature was lowered to 80℃, and 1.1g of glacial acetic acid was added for neutralization to obtain isooctanoic acid polyoxyethylene ester 400.

[0039] Comparative Example 2

[0040] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0041] First, add 288g of 2-ethyl-1-hexanoic acid, 800g of polyethylene glycol 400 and 0.2g of p-toluenesulfonic acid catalyst to a 2L four-necked flask, purge with nitrogen, start stirring, heat to 160℃ and react for 2 hours, then heat to 180℃ and react for 2 hours, finally heat to 200℃ and hold for 3 hours, cool to 70℃ and take a sample to measure the acid value. After the acid value is qualified, isooctanoic acid polyoxyethylene ester 400 is obtained.

[0042] Comparative Example 3

[0043] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0044] First, add 288g of 2-ethyl-1-hexanoic acid and 1.1g of [unclear text - possibly a specific ingredient or compound] to a 2.5L high-pressure reactor. Using KOH catalyst in a sealed reactor, the stirring was started and a vacuum was applied. The gas inside the reactor was then replaced three times with nitrogen. The temperature was raised to 100℃ for dehydration. After dehydration, the temperature was raised to 115-120℃, and 44g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 5g / min. The reaction temperature was controlled at 115-120℃, and the reaction pressure was kept below 0.5MPa. After the addition was complete, the reactor was allowed to mature until the pressure no longer dropped. Then, the temperature was raised to 140℃, and 756g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 10g / min. The reaction temperature was controlled at 140-145℃, and the reaction pressure was kept below 0.5MPa. After the addition was complete, the temperature was lowered to 120℃ for a second maturation until the pressure no longer dropped. The reactor was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80℃, and 1.1g of glacial acetic acid was added for neutralization to obtain isooctanoic acid polyoxyethylene ester 400.

[0045] Comparative Example 4

[0046] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0047] First, add 288g of 2-ethyl-1-hexanoic acid and 1.1g of [unclear text - possibly a specific ingredient or compound] to a 2.5L high-pressure reactor. Using KOH catalyst in a sealed reactor, the stirring was started and a vacuum was applied. The gas inside the reactor was then replaced three times with nitrogen. The temperature was raised to 100℃ for dehydration. After dehydration, the temperature was raised to 115-120℃, and 226g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 5g / min. The reaction temperature was controlled at 115-120℃, and the reaction pressure was kept below 0.5MPa. After the addition was complete, the reactor was allowed to mature until the pressure no longer dropped. Then, the temperature was raised to 140℃, and 574g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 10g / min. The reaction temperature was controlled at 140-145℃, and the reaction pressure was kept below 0.5MPa. After the addition was complete, the temperature was lowered to 120℃ for a second maturation until the pressure no longer dropped. The reactor was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80℃, and 1.1g of glacial acetic acid was added for neutralization to obtain isooctanoic acid polyoxyethylene ester 400.

[0048] Example 2

[0049] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0050] First, add 400g of lauric acid and 1.2g of [unclear text - possibly a type of chemical compound] to a 2.5L high-pressure reactor. Using KOH catalyst in a sealed reactor, the stirring was started and a vacuum was drawn. The gas inside the reactor was then replaced with nitrogen three times. The temperature was raised to 100℃ for dehydration. After dehydration, the temperature was raised to 115-120℃ and 88g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 5g / min. The reaction temperature was controlled at 115-120℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the reactor was allowed to mature until the pressure did not drop. Then, the temperature was raised to 140℃ and 712g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 10g / min. The reaction temperature was controlled at 140-145℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the temperature was lowered to 120℃ for a second maturation until the pressure did not drop. The reactor was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80℃ and 1.2g of glacial acetic acid was added for neutralization to obtain polyoxyethylene laurate 400.

[0051] Example 3

[0052] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0053] First, add 512g of palmitic acid and 1.3g of [unclear text - possibly a type of chemical compound] to a 2.5L high-pressure reactor. Using KOH catalyst in a sealed reactor, the stirring was started and a vacuum was drawn. The gas inside the reactor was then replaced with nitrogen three times. The temperature was raised to 100℃ for dehydration. After dehydration, the temperature was raised to 115-120℃ and 88g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 5g / min. The reaction temperature was controlled at 115-120℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the reactor was allowed to mature until the pressure did not drop. Then, the temperature was raised to 140℃ and 712g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 10g / min. The reaction temperature was controlled at 140-145℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the temperature was lowered to 120℃ for a second maturation until the pressure did not drop. The reactor was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80℃ and 1.3g of glacial acetic acid was added for neutralization to obtain polyoxyethylene palmitate 400.

[0054] Example 4

[0055] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0056] First, add 569g of stearic acid and 1.4g of... to a 2.5L high-pressure reactor. Using KOH catalyst in a sealed reactor, the stirring was started and a vacuum was drawn. The gas inside the reactor was then replaced with nitrogen three times. The temperature was raised to 100℃ for dehydration. After dehydration, the temperature was raised to 115-120℃ and 88g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 5g / min. The reaction temperature was controlled at 115-120℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the mixture was allowed to mature until the pressure did not drop. Then, the temperature was raised to 140℃ and 712g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 10g / min. The reaction temperature was controlled at 140-145℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the temperature was lowered to 120℃ for a second maturation until the pressure did not drop. The mixture was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80℃ and 1.4g of glacial acetic acid was added for neutralization to obtain polyoxyethylene stearate 400.

[0057] Example 5

[0058] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0059] First, add 508g of palmitoleic acid and 1.3g of [unclear text - possibly a type of chemical compound] to a 2.5L high-pressure reactor. Using KOH catalyst in a sealed reactor, the stirring was started and a vacuum was drawn. The gas inside the reactor was then replaced with nitrogen three times. The temperature was raised to 100℃ for dehydration. After dehydration, the temperature was raised to 115-120℃ and 88g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 5g / min. The reaction temperature was controlled at 115-120℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the mixture was allowed to mature until the pressure did not drop. Then, the temperature was raised to 140℃ and 712g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 10g / min. The reaction temperature was controlled at 140-145℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the temperature was lowered to 120℃ for a second maturation until the pressure did not drop. The mixture was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80℃ and 1.3g of glacial acetic acid was added for neutralization to obtain palmitoleic acid polyoxyethylene ester 400.

[0060] Example 6

[0061] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0062] First, add 567g of oleic acid and 1.4g of [unclear text - possibly a type of chemical compound] to a 2.5L high-pressure reactor. Using KOH catalyst in a sealed reactor, the stirring was started and a vacuum was drawn. The gas inside the reactor was then replaced with nitrogen three times. The temperature was raised to 100℃ for dehydration. After dehydration, the temperature was raised to 115-120℃ and 88g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 5g / min. The reaction temperature was controlled at 115-120℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the reactor was allowed to mature until the pressure did not drop. Then, the temperature was raised to 140℃ and 712g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 10g / min. The reaction temperature was controlled at 140-145℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the temperature was lowered to 90℃ for a second maturation until the pressure did not drop. The reactor was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80℃ and 1.4g of glacial acetic acid was added for neutralization to obtain oleic acid polyoxyethylene ester 400.

[0063] Example 7

[0064] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0065] First, 567g of oleic acid and 2.7g of KOH catalyst were added to a 2.5L high-pressure reactor. The reactor was sealed, stirred, and evacuated. Then, the gas inside the reactor was replaced with nitrogen three times. The temperature was raised to 90℃ for dehydration. After dehydration, 88g of ethylene oxide (first ethylene oxide) was added dropwise at 1g / min, controlling the reaction temperature at 90℃~95℃ and the reaction pressure within 0.5MPa. After the addition was complete, the mixture was allowed to mature until the pressure did not drop. Then, the temperature was raised to 100℃ and 712g of ethylene oxide (second ethylene oxide) was added dropwise at 5g / min, controlling the reaction temperature at 100℃~105℃ and the reaction pressure within 0.5MPa. After the addition was complete, the mixture was allowed to mature until the pressure did not drop. Degassing (pressure less than -0.098MPa) was performed for 10min. After degassing, the temperature was lowered to 80℃, and 2.7g of glacial acetic acid was added for neutralization to obtain oleic acid polyoxyethylene ester 400.

[0066] Example 8

[0067] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0068] First, 567g of oleic acid and 2.7g of NaOH catalyst were added to a 2.5L high-pressure reactor. The reactor was sealed, stirred, and evacuated. Then, the gas inside the reactor was replaced with nitrogen three times. The temperature was raised to 100℃ for dehydration. After dehydration, 88g of ethylene oxide (first ethylene oxide) was added dropwise at 2g / min, controlling the reaction temperature at 100℃~105℃ and the reaction pressure within 0.5MPa. After the addition was complete, the mixture was allowed to mature until the pressure did not drop. Then, the temperature was raised to 110℃ and 712g of ethylene oxide (second ethylene oxide) was added dropwise at 6g / min, controlling the reaction temperature at 110℃~115℃ and the reaction pressure within 0.5MPa. After the addition was complete, the mixture was allowed to mature until the pressure did not drop. Degassing (pressure less than -0.098MPa) was performed for 10min. After degassing, the temperature was lowered to 80℃, and 2.7g of glacial acetic acid was added for neutralization to obtain oleic acid polyoxyethylene ester 400.

[0069] Example 9

[0070] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0071] First, 567g of oleic acid and 2g of CH3ONa catalyst were added to a 2.5L high-pressure reactor. The reactor was sealed, stirred, and evacuated. Then, the gas inside the reactor was replaced with nitrogen three times. The temperature was raised to 100℃ for dehydration. After dehydration, 88g of ethylene oxide (first ethylene oxide) was added dropwise at 3g / min, controlling the reaction temperature at 110℃~115℃ and the reaction pressure within 0.5MPa. After the addition was complete, the mixture was allowed to mature until the pressure did not drop. Then, the temperature was raised to 120℃ and 712g of ethylene oxide (second ethylene oxide) was added dropwise at 7g / min, controlling the reaction temperature at 120℃~125℃ and the reaction pressure within 0.5MPa. After the addition was complete, the mixture was allowed to mature until the pressure did not drop. Degassing (pressure less than -0.098MPa) was performed for 10min. After degassing, the temperature was lowered to 80℃, and 2g of glacial acetic acid was added for neutralization to obtain oleic acid polyoxyethylene ester 400.

[0072] Example 10

[0073] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0074] First, add 567g of oleic acid and 1.4g of [unclear text - possibly a type of chemical compound] to a 2.5L high-pressure reactor. Using CH3OK catalyst in a sealed reactor, the stirring was started and a vacuum was drawn. The gas inside the reactor was then replaced with nitrogen three times. The temperature was raised to 100℃ for dehydration. After dehydration, 88g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 3g / min, controlling the reaction temperature at 115℃~120℃ and the reaction pressure below 0.5MPa. After the addition was complete, the reactor was allowed to mature until the pressure no longer dropped. Then, the temperature was raised to 130℃ and 712g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 7g / min, controlling the reaction temperature at 130℃~135℃ and the reaction pressure below 0.5MPa. After the addition was complete, the temperature was lowered to 120℃ for a second maturation, which was allowed to mature until the pressure no longer dropped. The reactor was then degassed (pressure less than -0.098MPa) for 10min. After degassed, the temperature was lowered to 80℃, and 1.4g of glacial acetic acid was added for neutralization to obtain oleic acid polyoxyethylene ester 400.

[0075] Example 11

[0076] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0077] First, add 567g of oleic acid and 0.55g of [unclear text - possibly a type of chemical compound] to a 2.5L high-pressure reactor. Using Na catalyst in a sealed reactor, the stirring was started and a vacuum was drawn. The gas inside the reactor was then replaced with nitrogen three times. The temperature was raised to 100°C for dehydration. After dehydration, 88g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 3g / min, controlling the reaction temperature at 115°C–120°C and the reaction pressure below 0.5MPa. After the addition was complete, the reactor was allowed to mature until the pressure no longer dropped. Then, the temperature was raised to 140°C and 712g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 8g / min, controlling the reaction temperature at 140°C–145°C and the reaction pressure below 0.5MPa. After the addition was complete, the temperature was lowered to 120°C for a second maturation, which was allowed to mature until the pressure no longer dropped. The reactor was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80°C, and 1.4g of glacial acetic acid was added for neutralization to obtain oleic acid polyoxyethylene ester 400.

[0078] Example 12

[0079] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0080] First, add 567g of oleic acid and 0.55g of mixed catalyst (KOH and NaOH) to a 2.5L high-pressure reactor. Seal the reactor, start stirring and evacuate. Then, replace the gas in the reactor with nitrogen three times. Raise the temperature to 100℃ for dehydration. After dehydration, add 88g of ethylene oxide (first ethylene oxide) dropwise at 3g / min. Control the reaction temperature at 115℃~120℃ and the reaction pressure within 0.5MPa. After the addition is complete, allow it to mature until the pressure no longer drops. Then, the temperature was raised to 160℃ and 712g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 10g / min. The reaction temperature was controlled between 160℃ and 165℃, and the reaction pressure was kept below 0.5MPa. After the addition was complete, the temperature was lowered to 120℃ for secondary ripening. The secondary ripening was continued until the pressure no longer dropped. The gas was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80℃, and 0.55g of glacial acetic acid was added for neutralization to obtain oleic acid polyoxyethylene ester 400.

[0081] Example 13

[0082] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0083] First, add 285g of stearic acid and 1.1g of [unclear text - possibly a type of chemical compound] to a 2.5L high-pressure reactor. Using KOH catalyst in a sealed reactor, the stirring was started and a vacuum was drawn. The gas inside the reactor was then replaced with nitrogen three times. The temperature was raised to 100℃ for dehydration. After dehydration, the temperature was raised to 115-120℃ and 66g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 5g / min. The reaction temperature was controlled at 115-120℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the reactor was allowed to mature until the pressure did not drop. Then, the temperature was raised to 140℃ and 734g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 10g / min. The reaction temperature was controlled at 140-145℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the temperature was lowered to 120℃ for a second maturation until the pressure did not drop. The reactor was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80℃ and 1.1g of glacial acetic acid was added for neutralization to obtain polyoxyethylene stearate 800.

[0084] Example 14

[0085] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0086] First, add 143g of stearic acid and 1.1g of [unclear text - possibly a type of chemical compound] to a 2.5L high-pressure reactor. Using KOH catalyst in a sealed reactor, the stirring was started and a vacuum was drawn. The gas inside the reactor was then replaced with nitrogen three times. The temperature was raised to 100℃ for dehydration. After dehydration, the temperature was raised to 115-120℃ and 44g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 5g / min. The reaction temperature was controlled at 115-120℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the mixture was allowed to mature until the pressure did not drop. Then, the temperature was raised to 140℃ and 756g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 10g / min. The reaction temperature was controlled at 140-145℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the temperature was lowered to 120℃ for a second maturation until the pressure did not drop. The mixture was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80℃ and 1.1g of glacial acetic acid was added for neutralization to obtain polyoxyethylene stearate 1600.

[0087] Example 15

[0088] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0089] First, add 143g of stearic acid and 1.1g of [unclear text - possibly a type of chemical compound] to a 2.5L high-pressure reactor. Using KOH catalyst in a sealed reactor, the stirring was started and a vacuum was drawn. The gas inside the reactor was then replaced with nitrogen three times. The temperature was raised to 100℃ for dehydration. After dehydration, the temperature was raised to 115-120℃ and 44g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 5g / min. The reaction temperature was controlled at 115-120℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the reactor was allowed to mature until the pressure did not drop. Then, the temperature was raised to 140℃ and 1556g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 10g / min. The reaction temperature was controlled at 140-145℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the temperature was lowered to 120℃ for a second maturation until the pressure did not drop. The reactor was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80℃ and 1.1g of glacial acetic acid was added for neutralization to obtain polyoxyethylene stearate 3200.

[0090] Example 16

[0091] A method for preparing a fatty acid polyoxyethylene ester specifically includes the following steps:

[0092] First, add 100g of stearic acid and 1.1g of... to a 2.5L high-pressure reactor. Using KOH catalyst in a sealed reactor, the stirring was started and a vacuum was drawn. The gas inside the reactor was then replaced with nitrogen three times. The temperature was raised to 100℃ for dehydration. After dehydration, the temperature was raised to 115-120℃ and 31g of ethylene oxide (first ethylene oxide) was added dropwise at a rate of 5g / min. The reaction temperature was controlled at 115-120℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the mixture was allowed to mature until the pressure no longer dropped. Then, the temperature was raised to 140℃ and 1518g of ethylene oxide (second ethylene oxide) was added dropwise at a rate of 10g / min. The reaction temperature was controlled at 140-145℃ and the reaction pressure was kept below 0.5MPa. After the addition was complete, the temperature was lowered to 120℃ for a second maturation until the pressure no longer dropped. The mixture was then degassed (pressure less than -0.098MPa) for 10 minutes. After degassed, the temperature was lowered to 80℃ and 1.1g of glacial acetic acid was added for neutralization to obtain polyoxyethylene stearate 4400.

[0093] Product performance testing

[0094] The products obtained in Examples 1-1, 1-2 and Comparative Examples 1-4 were subjected to determination of color, saponification value, free acid, dioxane, ethylene oxide and PEG.

[0095] (1) The content of free dioxane and ethylene oxide was determined by gas chromatography;

[0096] (2) The free acid content was determined by liquid chromatography-mass spectrometry;

[0097] (3) The saponification value was determined according to the method of HG / T 3505-2020 "Determination of Saponification Value of Nonionic Surfactants";

[0098] (4) The color was measured using a desktop spectrophotometer.

[0099] Table 1. Catalyst types used in Examples 1-1, 1-2 and Comparative Examples 1-4

[0100]

[0101]

[0102] Table 2 Comparison of product performance between Examples 1-1, 1-2 and Comparative Examples 1-4

[0103]

[0104] Table 2 shows that the product prepared in Example 1-1 had the lowest free acid, EO, PEG content, color, and dioxane content, and its saponification value matched the molecular weight of the feed ingredients. The product prepared in Example 1-2 had a significantly higher PEG content. The products prepared in Comparative Examples 1, 3, and 4 had higher EO, ​​dioxane, and PEG contents. The product prepared in Comparative Example 2 had a low saponification value, a dark color, and high free acid and PEG content.

[0105] Table 3. Types of initiators used in Examples 1-1 and 2-6

[0106]

[0107]

[0108] Table 4 Comparison of product performance results obtained in Examples 1-1 and Examples 2-6

[0109]

[0110] Table 4 shows that the PEG content gradually increases with the increase of fatty acid molecular weight, and the product prepared using unsaturated fatty acids has a darker color than the product prepared using saturated fatty acids. The products obtained in Examples 1-1 and Examples 2-6 have low free EO and dioxane contents, and their saponification values ​​match the molecular weights corresponding to the feed ingredients, indicating that the quality of products prepared using fatty acids within the scope of protection of this invention meets the requirements.

[0111] Table 5 Process parameters for Examples 7-12

[0112]

[0113]

[0114] Table 6 shows the performance comparison results of the products obtained in Examples 7-12.

[0115]

[0116] Table 6 shows that the contents of EO and dioxane decrease with increasing reaction temperature, while the color and PEG content increase with increasing temperature. Furthermore, the products prepared in Examples 7-12 exhibit low color, low free EO and dioxane content, and PEG content that meets product quality requirements. The saponification values ​​also conform to the molecular weights corresponding to the feed ingredients. This indicates that the products prepared under the reaction temperature, catalyst type, and dosage conditions within the scope of this invention have stable quality.

[0117] Table 7. Process parameters for Examples 4 and 13-16

[0118] Example PEG molecular weight in the product 4 400 13 800 14 1600 15 3200 16 4400

[0119] Table 8 shows the performance comparison results of the products obtained in Examples 4 and 13-16.

[0120]

[0121] The data in Table 8 show that the products prepared in Examples 4 and 13-16 have low contents of free EO and dioxane, their saponification values ​​match the molecular weights corresponding to the feed ingredients, and their color and PEG content meet the product quality requirements. This indicates that as the molecular weight of fatty acid polyoxyethylene esters increases, the product quality prepared using the method of this invention remains stable.

[0122] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for producing a polyoxyethylene ester of a fatty acid, characterized by, The method comprises the following steps: The fatty acid is mixed with a catalyst, and after nitrogen replacement and dehydration, the fatty acid is pre-reacted with the first ethylene oxide at a first temperature, and then the fatty acid is polymerized with the second ethylene oxide at a second temperature, and then the fatty acid is secondarily aged after cooling, and finally the fatty acid polyoxyethylene ester is prepared through degassing and neutralization; The molar ratio of the fatty acid to the first ethylene oxide is 1:0.8-2.2; The molar ratio of the fatty acid to the second ethylene oxide is 1:4-100; The first temperature is 110-120℃; The second temperature is 5-50℃ higher than the first temperature; The cooling process is cooling to 15-25℃ lower than the second temperature.

2. The production method according to claim 1, characterized by, The fatty acid comprises at least one of saturated fatty acids and unsaturated fatty acids with carbon atom number of 4-22.

3. The production method according to claim 2, characterized by, The fatty acid comprises at least one of 2-methyl-1-hexanoic acid, lauric acid, palmitic acid, stearic acid, palmitoleic acid and oleic acid.

4. The production method according to any one of claims 1 to 3, characterized by, The catalyst comprises at least one of Na, K, CH3OK, CH3ONa, KOH and NaOH.

5. The preparation method according to claim 4, characterized in that, The catalyst is added in an amount of 0.03%-0.5% of the total mass of the fatty acid polyoxyethylene ester.

6. The production method according to any one of claims 1 to 3, characterized by, The molar ratio of the fatty acid to the first ethylene oxide is 1:1-2; and the molar ratio of the fatty acid to the second ethylene oxide is 1:5-100.

7. The production method according to any one of claims 1 to 3, characterized by, The speed of adding the first ethylene oxide is 1-15g / min; and the speed of adding the second ethylene oxide is 1-15g / min.

8. The production method according to any one of claims 1 to 3, characterized by, The pressure of the pre-reaction is 0-0.5MPa; and the pressure of the polymerization is 0-0.5MPa.

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