Preparation method and application of quaternary ammonium salt ionic liquid

Abstract

The invention provides a preparation method and application of quaternary ammonium salt ionic liquid. The quaternary ammonium salt ionic liquid is obtained through reaction of quaternary tertiary amine PE-DMA4 and protonic acid. The quaternary ammonium salt ionic liquid is used as a catalyst, (methyl) acrylic acid hydroxyl ester and norbornene which are cheap and easy to obtain are used as raw materials, and one-step addition reaction is carried out to obtain an acrylate compound containing a bridge ring structure. The quaternary ammonium salt ionic liquid prepared by the invention can inhibit the self-polymerization reaction of a norbornene monomer in the reaction process, does not need to further separate a norbornene self-polymer, simplifies the process flow, and has higher yield.

Description

Technical Field:

[0001] The present invention belongs to the field of esterification reactions, and particularly relates to a method for preparing quaternary ammonium salt ionic liquids and their application in the preparation of acrylates. Background Art:

[0002] (Meth)acrylic norbornene ester is an acrylate compound obtained by the addition reaction of (meth)acrylic acid and norbornene. The special structure of its polymer has the characteristics of low shrinkage rate, high glass transition temperature, high gloss, and high hardness, and can be applied to fields such as coatings, adhesives, and inks to improve product performance. The reaction route is shown as follows:

[0003]

[0004] However, (meth)acrylic norbornene ester has a strong pungent odor, which limits the wide use of this monomer. Introducing an alkoxy group into the compound can reduce or eliminate the odor of the compound.

[0005] Currently, there are mainly two routes for synthesizing acrylate compounds containing a bridged ring structure in the prior art: One is the two-step route:

[0006] In the first step, ethylene glycol and norbornene are used as raw materials, and ethylene glycol mono-norbornenyl ether is prepared under the catalysis of boron trifluoride etherate; in the second step, ethylene glycol mono-norbornenyl ether and (meth)acrylic acid are used as raw materials, and an esterification reaction occurs under the action of an acidic catalyst to generate an acrylate compound containing a bridged ring structure and water. Since the second-step esterification reaction is a reversible reaction, it is necessary to continuously remove the water in the reaction system to promote the forward reaction.

[0007] The reaction route is shown as follows:

[0008]

[0009] The other is the one-step route

[0010] Patent JP 57200331 reported a method for preparing acrylate compounds containing a bridged ring structure by a one-step method, that is, using 2-hydroxyethyl methacrylate and dicyclopentadiene as raw materials, and under the action of a solid acid catalyst, the two react directly in one step to generate an acrylate compound containing a bridged ring structure, with a yield of 84%. However, the production process of this solid acid catalyst is complex, the cost is high, and such strong acid catalysts are prone to catalyze the self-polymerization reaction of bridged ring olefins, and the reaction selectivity is low.

[0011] Patent WO2011029610A reported a method for the one-step preparation of acrylate compounds containing a bridged ring structure by catalyzing the reaction of (meth)acrylic acid hydroxy esters with norbornene using metal salts such as copper trifluoromethanesulfonate as catalysts. Compared with solid acid catalysts, such catalysts inhibit the self-polymerization reaction of bridged ring olefins and have relatively high selectivity. However, after the reaction, an aqueous solution of sodium hydroxide is required to further remove the catalyst in the reaction solution, generating a large amount of wastewater.

[0012] In summary, the existing preparation methods are all relatively complex and have low yields. There is still a need to further develop a preparation method for norbornene acrylate with simple process, convenient operation and high yield to meet the industrial demand. Summary of the Invention:

[0013] To solve the above problems, the present invention provides a preparation method and application of a quaternary ammonium salt ionic liquid, which can be used to prepare acrylate compounds containing alkoxy and bridged ring structures. The compounds prepared by the method of the present invention have high yields and high selectivity.

[0014] A preparation method of a quaternary ammonium salt ionic liquid is obtained by reacting a quaternary tertiary amine PE-DMA4 with a protonic acid.

[0015] Preferably, the protonic acid is one or more of sulfuric acid, benzenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid.

[0016] Preferably, the structural formula of the quaternary tertiary amine PE-DMA4 is: The quaternary tertiary amine PE-DMA4 can be synthesized by known methods, such as the method described in the reference Shukla, Abhinav A., Sung Su Bae, James A. Moore, Kristopher A. Barnthouse and Steven M. Cramer. “Synthesis and Characterization of High-Affinity, Low-Molecular-Mass Displacers for Anion-Exchange Chromatography.” Industrial & Engineering Chemistry Research 37(1998):4090-4098.

[0017] Preferably, the molar ratio of the quaternary tertiary amine PE-DMA4 to the protonic acid is 1:1 to 4.

[0018] Preferably, the protonic acid is added to the quaternary tertiary amine PE-DMA4 at low temperature, and the reaction is carried out at room temperature after the protonic acid is completely added. The reaction is carried out under stirring conditions, and the reaction time is 2-3 h.

[0019] Preferably, the protonic acid is slowly added to the quaternary tertiary amine PE-DMA4, for example, by dropwise addition.

[0020] Preferably, the low temperature condition is below 20 °C.

[0021] The present invention also provides the application of the quaternary ammonium salt ionic liquid, which can be used for the reaction of (meth)acrylic acid hydroxy ester with norbornene to prepare an acrylate compound containing a bridged ring structure.

[0022] A method for manufacturing an acrylate compound containing a bridged ring structure, in the presence of the ionic liquid and inhibitor of the present invention, the (meth)acrylic acid hydroxy ester reacts with norbornene to obtain an acrylate compound containing a bridged ring structure.

[0023] Preferably, the dosage of the ionic liquid is 0.5-5% of the mass of norbornene.

[0024] (Meth)acrylic acid hydroxy ester is selected from one or more of hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), hydroxypropyl acrylate (HPA), hydroxypropyl methacrylate (HPMA), hydroxybutyl acrylate, hydroxybutyl methacrylate, 2-hydroxybutyl methacrylate, and 2-hydroxybutyl acrylate.

[0025] The inhibitor is selected from one or more of p-methoxyphenol, hydroquinone, 2,5-di-tert-butylhydroquinone, phenothiazine, 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide, tris(2,2,6,6-tetramethyl-4-piperidyl) phosphite, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate nitroxide, and copper dibutyldithiocarbamate.

[0026] Preferably, the dosage of the inhibitor is 0.05-1.0% of the total mass of (meth)acrylic acid hydroxy ester and norbornene.

[0027] Preferably, the molar ratio of the raw material (meth)acrylic acid hydroxy ester to norbornene is 1-3:1, preferably 1.2-1.5:1.

[0028] Preferably, the reaction temperature is 50-130 °C, preferably 60-80 °C, and the reaction time is 4-12 h.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The object of the present invention is to modify the structure of (meth)acrylic norbornene ester, improve and eliminate its odor by introducing an alkoxy group, and provide an ionic liquid and a preparation method thereof for synthesizing such acrylate compounds containing an alkoxy group and a bridged ring structure. The ionic liquid has the following three advantages: (1) Compared with metal salt catalysts such as copper trifluoromethanesulfonate, the reaction conditions are mild and the product selectivity is high; (2) The catalyst can be directly separated from the product by vacuum distillation, the separation difficulty is small, and the catalyst can be recycled; (3) Compared with solid acid catalysts, the preparation of this ionic liquid is simple and the cost is low. Using easily available (meth)acrylic hydroxy esters as raw materials, an addition reaction occurs with norbornene under the action of an ionic liquid catalyst and a polymerization inhibitor synthesized from a quaternary tertiary amine PE-DMA4 and a protonic acid, directly generating acrylate compounds containing a bridged ring structure in one step. The yield can reach more than 90%. The reaction solution can be directly subjected to vacuum rectification without further treatment to obtain a monomer product of acrylate with a bridged ring structure and a purity of more than 98.5%. Detailed implementation mode:

[0031] Source of raw materials:

[0032] Reagent Name Manufacturer Potassium Hydride Aladdin Tetrabromopenthaerythritol Aladdin N,N-Dimethylethanolamine InnoChem 2-Hydroxyethyl Methacrylate Wanhua Chemical 2-Hydroxyethyl Acrylate Aladdin 2-Hydroxypropyl Methacrylate Aladdin 2-Hydroxypropyl Acrylate Aladdin Norbornene Merck Chemical

[0033] The quaternary tertiary amine PE-DMA4, the synthesis method of which has been reported in the literature (Shukla, Abhinav A., Sung Su Bae, James A. Moore, Kristopher A. Barnthouse and Steven M. Cramer. “Synthesis and Characterization of High-Affinity, Low-Molecular-Mass Displacers for Anion-Exchange Chromatography.” Industrial & Engineering Chemistry Research 37(1998):4090 - 4098.), is prepared by the following method in this patent:

[0034] (1) Add 240 g of potassium hydride to a 5 L reaction kettle, add 1000 mL of DMF, stir well until dissolved, cool the system to 0 °C, and dropwise add a DMF solution of N,N'-dimethylethanolamine (445 g of N,N-dimethylethanolamine dissolved in 1000 mL of DMF solution). This solution is added dropwise within 2 h. After the addition is completed, stir at room temperature for 3 h, and then dropwise add a DMF solution of pentaerythritol tetrabromide (383 g of pentaerythritol tetrabromide dissolved in 1000 mL of DMF). This solution is added dropwise within 2 h, and then the system is heated to reflux for 30 h.

[0035] (2) After the reaction was completed, 4000 mL of deionized water and 2000 mL of ethyl acetate were added to the system. The oil phase was obtained by extraction. After adding anhydrous sodium sulfate to absorb water, ethyl acetate was removed by rotary evaporation to obtain 302 g of PE-DMA4 (yield 72%).

[0036] I. Preparation of quaternary ammonium salt ionic liquid

[0037] (1) 42.0 g of quaternary tertiary amine PE-DMA4 was added to a 250 mL single-necked flask equipped with a stirrer, a thermometer, and a condenser. Stirring was started and the system temperature was lowered to 15 °C;

[0038] (2) 36.9 g of 93 wt% concentrated sulfuric acid was added dropwise using a dropping funnel while maintaining the system temperature below 20 °C. After the addition was completed, the temperature was restored to room temperature and stirring was continued for 2.5 h to obtain a bright yellow viscous ionic liquid L1.

[0039] II. Preparation of acrylate containing a bridged ring structure

[0040] 195.0 g (1.5 mol, 1.5 eq.) of 2-hydroxyethyl methacrylate, 94.0 g (1.0 mol) of norbornene, 1.88 g of ionic liquid L1, and 0.29 g of inhibitor ZJ-701 were added to a 500 mL three-necked flask equipped with a stirrer, a thermometer, and a condenser. The temperature was raised to 60 °C and the reaction was carried out for 8 h to obtain a reaction solution containing norbornenyl ethoxy methacrylate. The obtained reaction solution was subjected to vacuum distillation to obtain 208.8 g of norbornenyl ethoxy methacrylate product, with a yield of 92% and a purity of 99.0%.

[0041]

[0042] Example 2

[0043] I. Preparation of quaternary ammonium salt ionic liquid

[0044] (1) 40.0 g of quaternary tertiary amine PE-DMA4 was added to a 250 mL single-necked flask equipped with a stirrer, a thermometer, and a condenser. Stirring was started and the system temperature was lowered to 15 °C;

[0045] (2) 36.7 g of methanesulfonic acid was added dropwise using a dropping funnel while maintaining the system temperature below 20 °C. After the addition was completed, the temperature was restored to room temperature and stirring was continued for 2 h to obtain a bright yellow viscous ionic liquid L2.

[0046] II. Preparation of acrylate containing a bridged ring structure

[0047] Into a 500 mL three-necked flask equipped with a stirrer, a thermometer, and a condenser, add 207.3 g (1.44 mol, 1.2 eq.) of hydroxypropyl methacrylate, 112.8 g (1.2 mol) of norbornene, 1.69 g of ionic liquid L2, 0.4 g of inhibitor ZJ-701, and 0.08 g of p-methoxyphenol. Heat the mixture to 70 °C and react for 6 h to obtain a reaction solution containing norbornenyl propoxy methacrylate. Subject the obtained reaction solution to vacuum distillation to obtain 265.1 g of norbornenyl propoxy methacrylate product, with a yield of 92% and a purity of 99.1%.

[0048]

[0049] Example 3

[0050] I. Preparation of quaternary ammonium salt ionic liquid

[0051] (1) Into a 250 mL single-necked flask equipped with a stirrer, a thermometer, and a condenser, add 68.0 g of quaternary tertiary amine PE-DMA4. Start stirring and cool the system temperature to 10 °C;

[0052] (2) Gradually add 48.6 g of trifluoromethanesulfonic acid dropwise using a dropping funnel, control the dropping rate to keep the system temperature below 20 °C, and after the dropping is complete, restore to room temperature and continue stirring and reacting for 3 h to obtain a bright yellow viscous ionic liquid L3.

[0053] II. Preparation of acrylate containing bridged ring structure

[0054] Into a 1000 mL three-necked flask equipped with a stirrer, a thermometer, and a condenser, add 348.0 g (3.0 mol, 2.0 eq.) of hydroxyethyl acrylate, 141 g (1.5 mol) of norbornene, 7.05 g of ionic liquid L3, and 0.98 g of phenothiazine. Heat the mixture to 60 °C and react for 5 h to obtain a reaction solution containing norbornenyl ethoxy acrylate. Subject the obtained reaction solution to vacuum distillation to obtain 301.4 g of norbornenyl ethoxy acrylate product, with a yield of 95% and a purity of 99.3%.

[0055]

[0056] Example 4

[0057] I. Preparation of quaternary ammonium salt ionic liquid

[0058] (1) Into a 250 mL single-necked flask equipped with a stirrer, a thermometer, and a condenser, add 68.0 g of quaternary tertiary amine PE-DMA4. Start stirring and cool the system temperature to 10 °C;

[0059] (2) Gradually add 77.1 g of trifluoromethanesulfonic acid drop by drop using a dropping funnel, control the dropping rate to keep the system temperature below 20 °C, and after the dropping is completed, return to room temperature and continue stirring and reacting for 3 h to obtain a bright yellow viscous ionic liquid L4.

[0060] II. Preparation of Acrylate Containing Bridged Ring Structure

[0061] Into a 1000 mL three-necked flask equipped with a stirrer, a thermometer, and a condenser, add 354.9 g (3.06 mol, 1.8 eq.) of hydroxypropyl acrylate, 159.8 g (1.7 mol) of norbornene, 4.79 g of ionic liquid L4, and 0.51 g of inhibitor ZJ-706. Heat up to 80 °C and react for 4 h to obtain a reaction solution containing norbornenyl propoxy acrylate. Carry out vacuum distillation on the obtained reaction solution to obtain 338.3 g of norbornenyl propoxy acrylate product, with a yield of 94% and a purity of 99.2%.

[0062]

[0063] Example 5

[0064] I. Preparation of Quaternary Ammonium Salt Ionic Liquid

[0065] (1) Into a 250 mL single-necked flask equipped with a stirrer, a thermometer, and a condenser, add 68.0 g of quaternary tertiary amine PE-DMA4, start stirring, and lower the system temperature to 10 °C;

[0066] (2) Add 76.7 g of benzenesulfonic acid in batches, control the dropping rate to keep the system temperature below 20 °C, and after the dropping is completed, return to room temperature and continue stirring and reacting for 3 h to obtain a bright yellow viscous ionic liquid L5.

[0067] II. Preparation of Acrylate Containing Bridged Ring Structure

[0068] Into a 1000 mL three-necked flask equipped with a stirrer, a thermometer, and a condenser, add 348 g (3.0 mol, 1.5 eq.) of hydroxypropyl acrylate, 188 g (2.0 mol) of norbornene, 5.36 g of ionic liquid L5, and 0.51 g of inhibitor ZJ-706. Heat up to 90 °C and react for 6 h to obtain a reaction solution containing norbornenyl propoxy acrylate. Carry out vacuum distillation on the obtained reaction solution to obtain 420.0 g of norbornenyl propoxy acrylate product, with a yield of 93% and a purity of 99.1%.

[0069]

[0070] Comparative Example 1

[0071] Into a 1000 mL three-necked flask equipped with a stirrer, a thermometer, and a condenser, 348 g (3.0 mol, 1.5 eq.) of hydroxypropyl acrylate, 188 g (2.0 mol) of norbornene, 3.61 g of copper trifluoromethanesulfonate, and 0.51 g of inhibitor ZJ-706 were added. The temperature was raised to 100 °C and the reaction was carried out for 4 h to obtain a reaction solution containing norbornenyl propyl acrylate. The obtained reaction solution was subjected to vacuum distillation to obtain 370.3 g of norbornenyl propyl acrylate product with a yield of 82% and a purity of 99.0%.

[0072]

[0073] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. Those skilled in the art can understand that some modifications or adjustments can be made to the present invention under the teaching of this specification. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A preparation method of a quaternary ammonium salt ionic liquid, characterized in that, It is obtained by reacting a quaternary tertiary amine PE-DMA4 with a protonic acid.

2. The preparation method according to claim 1, characterized in that, The protonic acid is one or more of sulfuric acid, benzenesulfonic acid, methanesulfonic acid, and trifluoromethanesulfonic acid. Preferably, the structural formula of the quaternary tertiary amine PE-DMA4 is as follows: Preferably, the molar ratio of the quaternary tertiary amine PE-DMA4 to the protonic acid is 1:1 to 4.

3. The preparation method according to claim 1, characterized in that, The protonic acid is added to the quaternary tertiary amine PE-DMA4 at a low temperature. After the protonic acid is completely added, the reaction is carried out at room temperature. The reaction is carried out under stirring conditions, and the reaction time is 2-3 h. Preferably, the low temperature condition is below 20 °C.

4. Use of the ionic liquid prepared by the preparation method according to any one of claims 1-3, which is used for the reaction of (meth)acrylic acid hydroxy ester with norbornene to prepare an acrylate compound containing a bridged ring structure.

5. A preparation method of an acrylate compound containing a bridged ring structure, in the presence of the ionic liquid and a polymerization inhibitor prepared by the preparation method according to any one of claims 1-3, the (meth)acrylic acid hydroxy ester and norbornene are subjected to an addition reaction to obtain an acrylate compound containing a bridged ring structure.

6. The preparation method according to claim 5, characterized in that, The dosage of the ionic liquid is 0.5-5% of the mass of norbornene.

7. The preparation method according to claim 5 or 6, characterized in that, (Meth)acrylic acid hydroxy ester is one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, 2-hydroxybutyl methacrylate, and 2-hydroxybutyl acrylate. Preferably, the polymerization inhibitor is selected from one or more of p-methoxyphenol, hydroquinone, 2,5-di-tert-butylhydroquinone, phenothiazine, 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide, tetramethylpiperidine nitroxide phosphite, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate nitroxide, and copper dibutyldithiocarbamate.

8. The preparation method according to any one of claims 5-7, characterized in that, The dosage of the polymerization inhibitor is 0.05-1.0% of the total mass of the (meth)acrylic acid hydroxy ester and norbornene. Preferably, the molar ratio of the raw material (meth)acrylic acid hydroxy ester to norbornene is 1-3:1, preferably 1.2-1.5:

1.

9. The preparation method according to any one of claims 5-8, characterized in that The reaction temperature is 50-130 °C, preferably 60-80 °C, and the reaction time is 4-12 h.

Images