Process for the ethoxylation of fatty alcohols

Abstract

The present application solves the problem of high dioxane content in the product material obtained by using BF3 as an acidic catalyst for the ethoxylation of fatty alcohols in the prior art, and provides a new method for the ethoxylation of fatty alcohols, which has the advantage of significantly lower dioxane content than traditional acidic catalysts, and the technical scheme is: a method for the ethoxylation of fatty alcohols, which comprises using a fatty alcohol as a starter, and in the presence of a catalyst, ring-opening polymerization of ethylene oxide to obtain a fatty alcohol ethoxylate product, characterized in that the catalyst comprises a main catalyst and a cocatalyst, the main catalyst comprises BF3, and the cocatalyst comprises at least one selected from the group consisting of a ruthenium salt, a carboxylate compound, and an organic phosphorus compound, wherein the ruthenium is in the +3 valence state.

Description

Technical Field

[0001] This invention relates to a method for the ethoxylation of fatty alcohols. Background Technology

[0002] The production of fatty alcohol polyoxyethylene ethers by ethoxylation of fatty alcohols often employs both alkaline and acidic catalysts, each with its own characteristics. For instance, acidic catalysts produce fatty alcohol polyoxyethylene ethers with a narrower molecular weight distribution, but the product contains higher levels of impurities such as polyethylene glycol and dioxane. To overcome the drawback of high polyethylene glycol and dioxane content in fatty alcohol ethoxylation products using acidic catalysts, numerous attempts have been made in existing technologies.

[0003] To reduce the residual polyethylene glycol (PEG) content in products, CN201510827159.5 discloses a method for purifying crude PEG-containing products. CN201510943100.2 discloses a method for removing dioxane using an adsorbent. CN201710240626.3 discloses a method for reducing PEG content using a treatment agent and a two-phase separation method. However, the above methods are post-processing methods, adding post-processing steps. If the generation of impurities can be reduced during the acid-catalyzed ethoxylation reaction, the post-processing load on the product will be significantly reduced. Summary of the Invention

[0004] The present invention addresses the problem of high dioxane content in the product obtained by using BF3 as an acidic catalyst for the ethoxylation of fatty alcohols in the prior art, and provides a new method for the ethoxylation of fatty alcohols, which yields a product with a significantly lower dioxane content than that obtained by traditional acidic catalysts.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A method for ethoxylation of fatty alcohols includes using a fatty alcohol as a starting agent and, in the presence of a catalyst, undergoing a ring-opening polymerization reaction of ethylene oxide to obtain a fatty alcohol ethoxylated product. The catalyst includes a main catalyst and a co-catalyst. The main catalyst includes BF3, and the co-catalyst includes at least one substance selected from the group consisting of ruthenium salts, carbon-isolated dicarbonyl compounds, and organophosphorus compounds, wherein ruthenium is in the +3 valence.

[0007] We found that the use of a co-catalyst reduced the residual amount of dioxane in fatty alcohol ethoxylation products compared to using BF3 catalyst alone.

[0008] In the above technical solution, BF3 is used in the form of a solution of BF3 dissolved in ether.

[0009] The BF3 in the above technical solution can be used in pure BF3 form, but it is more convenient to use it in a dissolved form. Commonly used solvents are ethers, especially C4-C8 ethers (such as, but not limited to, diethyl ether, dipropyl ether, dibutyl ether, anisole, tetrahydrofuran, etc.), with BF3 diethyl ether solution being the most common. Typically, the weight concentration of BF3 diethyl ether solution is 10-50%.

[0010] In the above technical solution, the preferred weight ratio of the co-catalyst to the main catalyst is greater than 0 and less than 0.5. For example, but not limited to, this weight ratio is 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, etc.

[0011] In the above technical solution, the preferred carbon-separated dicarbonyl compound conforms to the following structural formula 1: Structural Formula 1; wherein R1 and R2 are independently selected from hydrocarbon groups of C1 to C3, such as, but not limited to, hydrocarbon groups of C1, C2 and C3; R3 and R4 are independently selected from H or hydrocarbon groups, wherein the hydrocarbon groups are preferably hydrocarbon groups of C3 or less, such as hydrocarbon groups of C1, C2 and C3.

[0012] In the above technical solution, the organophosphorus compound preferably conforms to the following structural formula 2: Formula 2;

[0013] Among them, R5~R 19 Independently selected from H or hydrocarbon groups, and R5~R 19 The sum of the number of carbon atoms in all groups is 20 or less, for example, but not limited to R5 to R6. 19 The sum of the number of carbon atoms in all groups is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20.

[0014] In the above technical solution, it is preferable that the co-catalyst includes both the carbonyl compound and the phosphorus compound. In terms of reducing dioxane content, the carbonyl compound and the phosphorus compound have a synergistic effect, and this synergistic effect exists whether or not the co-catalyst includes ruthenium salt. The ratio between the phosphorus compound and the carbonyl compound is not particularly limited, for example, but not limited to, a weight ratio of 0.05 to 20. More specific, non-limiting examples of this weight ratio include 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, etc. A further narrower range of weight ratios includes 0.1 to 10, etc.

[0015] In the above technical solution, the co-catalyst preferably includes a first co-catalyst Ru and a second co-catalyst, wherein the second co-catalyst includes the carbonyl compound or the phosphorus compound, and the first co-catalyst and the second co-catalyst mutually promote each other in reducing dioxane.

[0016] In the above technical solution, the preferred weight ratio of the first co-catalyst to the second co-catalyst is 0.05 to 1, such as, but not limited to, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, etc.

[0017] In the above technical solution, the fatty alcohol is preferably a C8 to C18 alcohol. For example, but not limited to, the fatty alcohol includes at least one of the substances selected from the group consisting of C8 alcohols, C9 alcohols, C10 alcohols, C11 alcohols, C12 alcohols, C13 alcohols, C14 alcohols, C15 alcohols, C16 alcohols, C17 alcohols, and C18 alcohols.

[0018] In the above technical solution, the preferred total molar ratio of ethylene oxide to fatty alcohol is 0.5 to 5. For example, but not limited to, this molar ratio is 1, 1.5, 2, 2.5, 3, 3.5, 4, etc.

[0019] In the above technical solution, the preferred amount of catalyst is 0.02% to 2% of the total weight of the material after the reaction, and the catalyst is calculated based on the BF3 content therein. For example, but not limited to 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, etc.

[0020] In the above technical solution, the preferred reaction temperature is 70-130℃. For example, but not limited to 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, etc.

[0021] In the above technical solution, the preferred reaction pressure is greater than 0 and less than 0.4 MPa. For example, but not limited to, the reaction pressure is 0.05 MPa, 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa, 0.3 MPa, 0.35 MPa, etc.

[0022] The key technical aspect of this invention lies in the selection of the main catalyst and co-catalyst components. There are no particular restrictions on the method of obtaining the catalyst product; conventional mixing methods are sufficient. The order of mixing the components, whether mixing occurs outside the ethoxylation reactor or before the ethoxylation reaction within the reactor, has not been found to significantly affect the effectiveness of this invention. For the sole purpose of comparison and saving on equipment used separately for catalyst preparation, it is recommended that the catalyst components be added to the ethoxylation reactor already containing the fatty alcohol before the ethoxylation reaction, as used in the specific embodiments of this invention.

[0023] In this invention, all ruthenium salts are measured in ruthenium.

[0024] In this invention, all pressure refers to gauge pressure.

[0025] In a specific embodiment of the present invention, the residual amount of dioxane in the product is measured using the following method:

[0026] GB / T 26388-2011 Determination of dioxane residues in surfactants – Internal standard method in gas chromatography.

[0027] The present invention will now be described in detail through specific embodiments. Detailed Implementation

[0028] In the embodiments and comparative examples of this invention, BF3 was provided as a 47% BF3 diethyl ether solution, and Ru was provided as ruthenium trichloride.

[0029]

Comparative Example 1

[0030] 372 g of dodecanol and 3.0 g of BF3 were added to a 1.5 L stirred tank. The tank lid was tightly closed, and the stirring was started. The stirring speed was set to 300 r / min. Nitrogen was used to purge the mixture three times. After maintaining the gauge pressure at -0.098 MPa for 1 hour, ethylene oxide was slowly introduced to carry out the polymerization reaction. The reaction temperature was controlled at 110 °C and the reaction pressure was controlled at 0.2 MPa until the total weight of ethylene oxide introduced was 264 g. Then, the mixture was kept at 110 °C for curing until the pressure no longer dropped. The vacuum pump was turned on to evacuate the tank and maintain the gauge pressure at -0.098 MPa for 30 minutes. The mixture was then cooled to 70 °C and discharged to obtain the dodecanol ethoxylated product with a dioxane content of 31.5 ppmw.

[0031]

Example 1

[0032] 372 g of dodecanol, 3.0 g of BF3, and 0.3 g of Ru were added to a 1.5 L stirred tank. The tank lid was tightly closed, and stirring was started at a speed of 300 r / min. Nitrogen was used to purge the mixture three times. After maintaining a gauge pressure of -0.098 MPa for 1 hour, ethylene oxide was slowly introduced to carry out the polymerization reaction. The reaction temperature was controlled at 110 °C and the reaction pressure was controlled at 0.2 MPa until the total weight of ethylene oxide introduced was 264 g. Then, the mixture was kept at 110 °C for curing until the pressure no longer dropped. The vacuum pump was turned on to evacuate the tank and maintain the gauge pressure at -0.098 MPa for 30 minutes. The mixture was then cooled to 70 °C and discharged to obtain the dodecanol ethoxylated product with a dioxane content of 24.8 ppmw.

[0033]

Example 2

[0034] 372 g of dodecanol, 3.0 g of BF3, and 0.3 g of acetylacetone were added to a 1.5 L stirred tank. The tank lid was tightly closed, and the stirring was started at a speed of 300 r / min. Nitrogen was used to purge the mixture three times. After maintaining a gauge pressure of -0.098 MPa for 1 hour, ethylene oxide was slowly introduced to carry out the polymerization reaction. The reaction temperature was controlled at 110 °C and the reaction pressure was controlled at 0.2 MPa until the total weight of ethylene oxide introduced was 264 g. Then, the mixture was kept at 110 °C for curing until the pressure no longer dropped. The vacuum pump was turned on to evacuate the tank and maintain the gauge pressure at -0.098 MPa for 30 minutes. The mixture was then cooled to 70 °C and discharged to obtain the dodecanol ethoxylated product with a dioxane content of 26.7 ppmw.

[0035]

Example 3

[0036] 372 g of dodecanol, 3.0 g of BF3, and 0.3 g of triphenylphosphine were added to a 1.5 L stirred tank. The tank lid was tightly closed, and the stirring was started at a speed of 300 r / min. Nitrogen was used to purge the mixture three times. After maintaining a gauge pressure of -0.098 MPa for 1 hour, ethylene oxide was slowly introduced to carry out the polymerization reaction. The reaction temperature was controlled at 110 °C and the reaction pressure was controlled at 0.2 MPa until the total weight of ethylene oxide introduced was 264 g. Then, the mixture was kept at 110 °C for curing until the pressure no longer dropped. The vacuum pump was turned on to evacuate the tank and maintain the gauge pressure at -0.098 MPa for 30 minutes. The mixture was then cooled to 70 °C and discharged to obtain the dodecanol ethoxylated product with a dioxane content of 21.1 ppmw.

[0037]

Example 4

[0038] 372 g of dodecanol, 3.0 g of BF3, 0.2 g of acetylacetone, and 0.1 g of triphenylphosphine were added to a 1.5 L stirred tank. The tank lid was tightly closed, and the stirring was started at a speed of 300 r / min. Nitrogen was used to purge the mixture three times. After maintaining a gauge pressure of -0.098 MPa for 1 hour, ethylene oxide was slowly introduced to carry out the polymerization reaction. The reaction temperature was controlled at 110 °C and the reaction pressure was controlled at 0.2 MPa until the total weight of ethylene oxide introduced was 264 g. Then, the mixture was kept at 110 °C for curing until the pressure no longer dropped. The vacuum pump was turned on to evacuate the tank and maintain the gauge pressure at -0.098 MPa for 30 minutes. The mixture was then cooled to 70 °C and discharged to obtain the dodecanol ethoxylated product with a dioxane content of 13.4 ppmw.

[0039]

Example 5

[0040] 372 g of dodecanol, 3.0 g of BF3, 0.1 g of Ru, and 0.2 g of acetylacetone were added to a 1.5 L stirred tank. The tank lid was tightly closed, and the stirring was started at a speed of 300 r / min. Nitrogen was used to purge the mixture three times. After maintaining a gauge pressure of -0.098 MPa for 1 hour, ethylene oxide was slowly introduced to carry out the polymerization reaction. The reaction temperature was controlled at 110 °C and the reaction pressure was controlled at 0.2 MPa until the total weight of ethylene oxide introduced was 264 g. Then, the mixture was kept at 110 °C for curing until the pressure no longer dropped. The vacuum pump was turned on to evacuate the tank and maintain the gauge pressure at -0.098 MPa for 30 minutes. The mixture was then cooled to 70 °C and discharged to obtain the dodecanol ethoxylated product with a dioxane content of 16.4 ppmw.

[0041]

Example 6

[0042] 372 g of dodecanol, 3.0 g of BF3, 0.1 g of Ru, and 0.2 g of triphenylphosphine were added to a 1.5 L stirred tank. The tank lid was tightly closed, and the stirring was started at a speed of 300 r / min. Nitrogen was used to purge the mixture three times. After maintaining a gauge pressure of -0.098 MPa for 1 hour, ethylene oxide was slowly introduced to carry out the polymerization reaction. The reaction temperature was controlled at 110 °C and the reaction pressure was controlled at 0.2 MPa until the total weight of ethylene oxide introduced was 264 g. Then, the mixture was kept at 110 °C for curing until the pressure no longer dropped. The vacuum pump was turned on to evacuate the tank and maintain the gauge pressure at -0.098 MPa for 30 minutes. The mixture was then cooled to 70 °C and discharged to obtain the dodecanol ethoxylated product with a dioxane content of 9.9 ppmw.

[0043]

Example 7

[0044] 372 g of dodecanol, 3.0 g of BF3, 0.1 g of Ru, 0.1 g of acetylacetone, and 0.1 g of triphenylphosphine were added to a 1.5 L stirred tank. The tank lid was tightly closed, and the stirring was started at a speed of 300 r / min. Nitrogen was used to purge the mixture three times. After maintaining a gauge pressure of -0.098 MPa for 1 hour, ethylene oxide was slowly introduced to carry out the polymerization reaction. The reaction temperature was controlled at 110 °C and the reaction pressure was controlled at 0.2 MPa until the total weight of ethylene oxide introduced was 264 g. Then, the mixture was kept at 110 °C for curing until the pressure no longer dropped. The vacuum pump was turned on to evacuate the tank and maintain the gauge pressure at -0.098 MPa for 30 minutes. The mixture was then cooled to 70 °C and discharged to obtain the dodecanol ethoxylated product with a dioxane content of 2.7 ppmw.

[0045] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for ethoxylation of fatty alcohols, comprising using a fatty alcohol as a starting agent and, in the presence of a catalyst, undergoing a ring-opening polymerization reaction of ethylene oxide to obtain an ethoxylated product of the fatty alcohol, characterized in that... The catalyst comprises a main catalyst and a co-catalyst. The main catalyst comprises BF3, and the co-catalyst comprises at least one substance selected from the group consisting of carbon-separated dicarbonyl compounds and organophosphorus compounds; wherein the organophosphorus compound conforms to the following structural formula 2: Structure 2; Among them, R5~R 19 Independently selected from H or hydrocarbon groups, and R5~R 19 The sum of the number of carbon atoms in all groups is less than 20; The carbon-separated dicarbonyl compound conforms to the following structural formula 1: Structure 1; R1 and R2 are independently selected from C1 to C3 hydrocarbon groups; R3 and R4 are independently selected from H or hydrocarbon groups.

2. The method according to claim 1, characterized in that: BF3 is used in the form of a solution of BF3 dissolved in ether.

3. The method according to claim 1, characterized in that: The weight ratio of the co-catalyst to the main catalyst is greater than 0 and less than 0.

5.

4. The method according to claim 1, characterized in that: The fatty alcohols mentioned are C8 to C18 alcohols.

5. The method according to claim 1, characterized in that: The total molar ratio of ethylene oxide to fatty alcohol is 0.5~5.

6. The method according to claim 1, characterized in that: The amount of catalyst used is equivalent to 0.02~2% of the total weight of the material after the reaction, and the catalyst is calculated based on the BF3 contained therein.

7. The method according to claim 1, characterized in that: The reaction temperature is 70~130℃.

8. The method according to claim 1, characterized in that: The reaction pressure is greater than 0 and less than 0.4 MPa.

Images