Process for producing (meth)acrylate monomers of polyalkoxylated alcohols
By using metal hydroxide catalysts such as sodium hydroxide or potassium hydroxide to react with polyalkoxylated alcohols to form an activated mixture, which then reacts with alkyl methacrylates, the problems of high cost and low conversion rate in the prior art are solved, achieving faster transesterification and high conversion rate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ROHM & HAAS CO
- Filing Date
- 2024-11-07
- Publication Date
- 2026-05-29
AI Technical Summary
In the existing technology, the synthesis of (meth)acrylate monomers of polyethoxylated alcohols or polyalkoxylated alcohols using lithium hydroxide catalysts is costly and has low conversion rates, requiring a more economical and efficient catalytic method.
A metal hydroxide catalyst, such as sodium hydroxide or potassium hydroxide, is mixed with a polyalkoxylated alcohol and dried to form an activated mixture, which is then reacted with alkyl (meth)acrylates. This avoids the use of additional solvents, reduces water content, and increases the transesterification rate.
It achieves a faster transesterification reaction rate and higher conversion rate, reduces production costs, avoids the high cost of traditional lithium-based catalysts, and improves production efficiency.
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Abstract
Description
Technical Field
[0001] The present invention relates to the generation of (meth)acrylate monomers of polyalkoxylated alcohols. Background Technology
[0002] (Meth)acrylate monomers of polyethoxylated alcohols or polyalkoxylated alcohols are typically synthesized via direct esterification or transesterification.
[0003] A common method for producing (meth)acrylate monomers of polyethoxylated alcohols or polyalkoxylated alcohols is to transesterify the polyethoxylated alcohol or polyalkoxylated alcohol with an alkyl (meth)acrylate using a transesterification catalyst such as lithium hydroxide (LiOH) or tetraethylhexyl titanate (TEHT). Typically, the polyalkoxylated alcohol is mixed with an alkyl (meth)acrylate, then dehydrated, followed by the addition of a transesterification catalyst (e.g., LiOH) to form the (meth)acrylate monomer of the polyalkoxylated alcohol.
[0004]
[0005] Polyethoxylated alcohols or polyalkoxylated alcohols are typically synthesized via the base-catalyzed ethoxylation of fatty alcohols. Commonly used base catalysts include sodium hydroxide (NaOH) and potassium hydroxide (KOH). These ethoxylation or alkoxylation reactions are terminated by neutralization with acids such as acetic acid or phosphoric acid.
[0006] It has been found that acid neutralization of polyethoxylated alcohols or polyalkoxylated alcohols can quench the transesterification catalyst LiOH and lead to uneven production. No other hydroxides such as NaOH and KOH have been found to provide any perceptible conversion under similar transesterification conditions for LiOH-catalyzed transesterification reactions to produce (meth)acrylate monomers of polyethoxylated alcohols or polyalkoxylated alcohols.
[0007] With the rapidly increasing cost of lithium-based catalysts, there is a need for an improved method for producing (meth)acrylate monomers of polyethoxylated alcohols or polyalkoxylated alcohols. This invention addresses one or more problems associated with conventional methods for producing (meth)acrylate monomers of polyethoxylated alcohols or polyalkoxylated alcohols. Summary of the Invention
[0008] This invention provides a method for producing (meth)acrylate monomers of polyalkoxylated alcohols. The method includes adding a metal hydroxide catalyst to a neutralized polyalkoxylated alcohol to form an activated mixture. The activated mixture is then dried to remove water. After drying, an alkyl (meth)acrylate is added to the dried activated mixture, and the alkyl (meth)acrylate reacts with the polyalkoxylated alcohol in the dried activated mixture to produce (meth)acrylate monomers of the polyalkoxylated alcohol. Detailed Implementation
[0009] This invention relates to a method for forming (meth)acrylate monomers of polyalkoxylated alcohols. In this method, a metal hydroxide catalyst is added to the polyalkoxylated alcohol to form an activated mixture. The activated mixture is then dried to remove water from the mixture. An alkyl (meth)acrylate is added to the dried activated mixture and reacted with the polyalkoxylated alcohol in the dried activated mixture to produce (meth)acrylate monomers of the polyalkoxylated alcohol. This discovery is important because it allows the use of catalysts other than lithium hydroxide and / or enables transesterification at a faster rate than conventional lithium hydroxide-catalyzed transesterification reactions.
[0010] As used herein, the term "(meth)acrylate" refers to acrylate or methacrylate or combinations thereof. As used herein, the term "substituted" means having at least one attached chemical group, such as an alkyl group, alkenyl group, vinyl group, hydroxyl group, carboxylic acid group, other functional group, or combinations thereof.
[0011] To avoid being limited by theory, it is believed that a metal hydroxide catalyst is added to the polyalkoxylated alcohol to form an activated mixture, which is then dried to obtain a mixture containing a salt of the polyalkoxylated alcohol. It is believed that the salt of the polyalkoxylated alcohol reacts with an alkyl methacrylate (e.g., methyl methacrylate) to form the desired (meth)acrylate monomer of the polyalkoxylated alcohol. An example of the reaction is shown below.
[0012]
[0013] The metal hydroxide catalyst can be selected from strong bases, including sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide, and calcium hydroxide. Preferably, the metal hydroxide catalyst is selected from sodium hydroxide and potassium hydroxide. More preferably, the metal hydroxide catalyst comprises sodium hydroxide. The metal hydroxide catalyst is preferably added to the polyalkoxylated alcohol in a dry form. By adding the metal hydroxide catalyst in a dry form, the amount of water that needs to be removed subsequently can be reduced.
[0014] This result is particularly surprising because NaOH and KOH typically do not produce perceptible conversions when used in conventional transesterification reactions of alkyl (meth)acrylates and polyalkoxylated alcohols catalyzed by lithium hydroxide (LiOH). Other transesterification reactions, such as the production of biodiesel, can use sodium hydroxide or potassium hydroxide as transesterification catalysts. However, these transesterification reactions use solvents such as methanol, which increase the solubility of the catalyst and make them catalyze the reaction efficiently. Preferably, no additional solvents, such as methanol or other solvents that increase the solubility of the transesterification catalyst, are added to the reaction in the method of the present invention.
[0015] During the activation of the polyalkoxylated alcohol, the mixture of the metal hydroxide catalyst and the polyalkoxylated alcohol is dried to remove water. Preferably, the drying step reduces the amount of water in the mixture of the metal hydroxide catalyst and the polyalkoxylated alcohol to less than 10% by weight relative to the total weight of the mixture. More preferably, the amount of water in the dried activated mixture is less than 5% by weight relative to the total weight of the metal hydroxide catalyst and the polyalkoxylated alcohol, even more preferably less than 1% by weight, and still more preferably less than 0.5% by weight. Even more preferably, the amount of water in the dried activated mixture is less than 0.1% by weight relative to the total weight of the metal hydroxide catalyst and the polyalkoxylated alcohol.
[0016] The drying step can be performed using any method known in the art. For example, the mixture can be dried by heating it to an elevated temperature under reduced pressure with or without an inert gas injection (such as nitrogen or argon).
[0017] Preferably, the polyalkoxylated alcohol comprises a compound of formula (I):
[0018] R(OR 1 ) n OH(I)
[0019] Wherein R is an alkyl group containing 8 to 24 carbon atoms, preferably 10 to 20 carbon atoms. 1 It is an alkenyl group containing 2 to 4 carbon atoms, preferably 2 or 3 carbon atoms (i.e., vinyl or propenyl groups), and more preferably 2 carbon atoms (i.e., vinyl groups). The variable n is in the range of 10 to 30, preferably 15 to 25.
[0020] Examples of polyalkoxylated alcohols include cetyl alcohol ethoxylate, stearyl alcohol ethoxylate, lauryl alcohol ethoxylate, and combinations thereof (e.g., cetearyl alcohol ethoxylate). The polyalkoxylated alcohol is preferably a neutralized polyalkoxylated alcohol, i.e., an alcohol is added during the production of the polyalkoxylated alcohol to terminate the reaction.
[0021] Alkyl methacrylate is preferably methyl methacrylate or methyl acrylate. More preferably, alkyl methacrylate is methyl methacrylate.
[0022] Preferably, the alkyl methacrylate is added to the reaction mixture in a molar excess relative to the polyalkoxylated alcohol. Preferably, the molar ratio of the alkyl methacrylate to the polyalkoxylated alcohol is greater than 1:1, more preferably at least 1.5:1, and even more preferably at least 2:1.
[0023] Polymerization inhibitors can be added together with alkyl (meth)acrylates to prevent unwanted polymerization. Suitable polymerization inhibitors are known in the art. For example, 4-hydroxy-TEMPO (4-HT), hydroquinone monomethyl ether (MeHQ), or phenothiazine (PTZ) can be used as polymerization inhibitors.
[0024] The transesterification reaction can be carried out at temperatures ranging from 100°C to 140°C, preferably from 110°C to 130°C. The transesterification reaction is preferably carried out at pressures below atmospheric pressure.
[0025] Some embodiments of the present invention will now be described in detail in the following examples.
[0026] Example
[0027] Embodiments of the present invention
[0028] Neutralized polyethoxylated alcohol (LA-23 from BASF, 255.9 g, 0.2 mol) and ground NaOH powder (0.163 g, 0.004 mol) were added to a 1000 mL four-necked flask equipped with a stirrer, thermometer, 10-plate distillation head, and reflux separator. The resulting mixture was heated to 90 °C under full vacuum and held for 1 hour to remove water. A sample was taken for NMR analysis, and methyl methacrylate (MMA, 136.5 g, 1.36 mol) and polymerization inhibitor 4-HT (0.25 g) were added to the mixture. The reaction mixture was heated to a set point of 115 °C under reduced pressure (550 mmHg). The vapor temperature varied between 57 °C and 60 °C. The reflux / distillation separator was set to 70 / 30, and the distillate was collected over one hour, at which point the vapor temperature began to rise. The collected MMA / MeOH distillate was 12 mL / 8.7 g. 1H-NMR analysis of the reaction mixture showed a 99% conversion of the polyethoxylated alcohol.
[0029] Excess MMA was distilled off at 200 mmHg to 1 mmHg, and the resulting mixture was diluted with 78 g GMAA and 39 g water.
[0030] Comparative Example #1
[0031] Neutralized cetearyl alcohol ethoxylate (CSA-20 from BASF, 278.1 g, 0.224 mol), methyl methacrylate (MMA, 149.5 g, 1.49 mol), and polymerization inhibitor 4-HT (0.25 g) were added to a 1000 ml four-necked flask equipped with a stirrer, thermometer, 10-plate distillation head, and reflux separator. The resulting mixture was dehydrated by distilling off 30 g of MMA under vacuum at 550 mmHg and a reactor temperature of 105 °C. After dehydration, the contents were cooled, and NaOH (0.2 g, 0.005 mol) was added. The resulting mixture was heated to a set point of 115 °C under reduced pressure at 550 mmHg.
[0032] After heating at 109°C for 1 hour, the vapor temperature remained above 90°C, indicating that no MeOH was produced. The absence of MeOH production indicates that no transesterification occurred.
[0033] Comparative Example #2
[0034] Neutralized cetearyl alcohol ethoxylate (CSA-20 from BASF, 278.1 g, 0.224 mol), methyl methacrylate (MMA, 180 g, 1.8 mol), and polymerization inhibitor 4-HT (0.25 g) were added to a 1000 ml four-necked flask equipped with a stirrer, thermometer, 10-plate distillation head, and reflux separator. The resulting mixture was dehydrated by distilling off 29 g of MMA at a reactor temperature of 105 °C under vacuum of 550 mmHg. After dehydration, the contents were cooled, and LiOH (0.205 g, 0.005 mol) was added. The resulting mixture was heated to a set point of 115 °C under reduced pressure of 550 mmHg. The vapor temperature varied between 57 °C and 60 °C. The reflux / distillation separator was set to 70 / 30, and the distillate was collected over three hours, at which point the vapor temperature began to rise and reached 65 °C. The collected MMA / MeOH distillate amounted to 14 ml / 11.1 g. The reaction mixture... 1 H-NMR analysis showed a 99% conversion rate of MACOL alcohol.
[0035] Excess MMA was distilled off at 200 mmHg to 1 mmHg, and the resulting mixture was diluted with 85 g GMAA and 43 g water.
[0036] A comparison of the embodiments of the present invention and Comparative Example #1 surprisingly shows that the polyethoxylated alcohol can be transesterified with MMA by activating and drying the mixture of polyethoxylated alcohol and NaOH. In Comparative Example #1, NaOH could not catalyze the transesterification reaction. A comparison of the embodiments of the present invention and Comparative Example #2 surprisingly shows that the embodiments of the present invention can complete the transesterification reaction faster than using a conventional LiOH transesterification catalyst.
Claims
1. A method for producing (meth)acrylate monomers of polyalkoxylated alcohols, the method comprising: A metal hydroxide catalyst is added to a polyalkoxylated alcohol to form an activated mixture; The activated mixture of the metal hydroxide catalyst and the polyalkoxylated alcohol is dried to remove water; as well as Alkyl (meth)acrylate is added to the dried activated mixture, and the alkyl (meth)acrylate is reacted with the polyalkoxylated alcohol to produce the (meth)acrylate monomer of the polyalkoxylated alcohol.
2. The method according to claim 1, wherein the metal hydroxide catalyst comprises sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide, or calcium hydroxide.
3. The method according to claim 2, wherein the metal hydroxide catalyst comprises sodium hydroxide or potassium hydroxide.
4. The method according to any one of the preceding claims, wherein the polyalkoxylated alcohol comprises a compound of formula (I). R(OR 1 ) n OH(I) in: R is an alkyl group containing 8 to 24 carbon atoms; R 1 It is an alkenyl group containing 2 to 4 carbon atoms; and n is in the range of 10 to 30.
5. The method according to claim 4, wherein R is an alkyl group comprising 10 to 20 carbon atoms.
6. The method according to claim 5, wherein R is an alkyl group comprising 12 to 16 carbon atoms.
7. The method of claim 4, wherein R 1 It is a vinyl or propylene group.
8. The method of claim 7, wherein R 1 It is a vinyl group.
9. The method of claim 4, wherein n is in the range of 15 to 25.
10. The method of claim 1, wherein the polyalkoxylated alcohol is selected from cetyl alcohol ethoxylate, stearyl alcohol ethoxylate, lauryl alcohol ethoxylate, and combinations thereof.
11. The method according to any one of the preceding claims, wherein drying the mixture comprises reducing the amount of water in the mixture to less than 10% by weight relative to the total weight of the mixture.
12. The method of claim 11, wherein drying the mixture comprises reducing the amount of water in the mixture to less than 2% by weight relative to the total weight of the mixture.
13. The method according to any one of the preceding claims, wherein the (meth)acrylate is methyl methacrylate.
14. The method according to any one of the preceding claims, the method further comprising adding a polymerization inhibitor to the dried activation mixture.