Solid acid catalyst and preparation method thereof, and preparation method of diethylene glycol dimethacrylate

Abstract

The invention relates to the technical field of preparation methods of diethylene glycol dimethacrylate, in particular to a solid acid catalyst and a preparation method thereof and a preparation method of diethylene glycol dimethacrylate, the solid acid catalyst comprises-[CH2-CH (C6H5)-CH2-R] n-with the content not less than 85%, R represents an acidic functional group, n represents the number of repetitive units, and n represents the number of the repetitive units. The preparation method comprises the following steps: filling a pervaporation membrane reactor with the solid acid catalyst, introducing raw materials, a solvent and an auxiliary agent into the reactor, carrying out ester exchange reaction on the raw materials under the action of the solid acid catalyst, and after the reaction is finished, separating and purifying a product to obtain diethylene glycol dimethacrylate. By adopting the method, the diethylene glycol dimethacrylate can be efficiently prepared in the pervaporation membrane reactor by utilizing the solid acid catalyst, the method has the advantages of simplicity and convenience in operation, high reaction efficiency, high product purity and the like, and the solid acid catalyst can be recycled after the reaction, so that the production cost is effectively reduced, and meanwhile, the environmental pollution is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of diethylene glycol dimethacrylate preparation methods, in particular to a solid acid catalyst and a preparation method thereof, and a preparation method of diethylene glycol dimethacrylate. Background Art

[0002] Diethylene glycol dimethacrylate (DEGDMA) is an organic compound with the chemical formula C 10 H 14 O4 is a colorless liquid with a refractive index of 1.4549 and is slightly soluble in water. As an important organic chemical raw material, diethylene glycol dimethacrylate is widely used in coatings, adhesives, resin modifiers and other fields.

[0003] Traditional methods for preparing diethylene glycol dimethacrylate mostly use liquid acid catalysts, which have problems such as difficult catalyst recovery, harsh reaction conditions, and low product purity. Therefore, it is particularly important to develop a method for preparing diethylene glycol dimethacrylate using a solid acid catalyst that is efficient, environmentally friendly, easy to industrialize, and universal. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a solid acid catalyst and a preparation method thereof, and a preparation method of diethylene glycol dimethacrylate. The solid acid catalyst and the preparation method thereof, and the preparation method of diethylene glycol dimethacrylate solve the problems of preparing diethylene glycol dimethacrylate by using a liquid acid catalyst, difficulty in catalyst recovery, harsh reaction conditions, and low product purity.

[0005] To achieve the above object, the first aspect of the embodiment of the present invention provides a solid acid catalyst, wherein the solid acid catalyst comprises -[CH2-CH(C6H5)-CH2-R] n -, wherein R is a sulfonic acid group or a carboxylic acid group, and n represents the number of repeating units.

[0006] A second aspect of an embodiment of the present invention provides a method for preparing a solid acid catalyst, comprising:

[0007] Chloromethyl polystyrene resin and concentrated sulfuric acid are mixed in a mass ratio of 1:5 to 1:20, placed in a reaction kettle, and the sulfonation temperature is controlled to be 100° C.-160° C., and the sulfonation time is 1 h-8 h to carry out a sulfonation reaction to obtain a sulfonated polystyrene resin solid acid catalyst with catalytic activity.

[0008] A third aspect of an embodiment of the present invention provides a method for preparing a solid acid catalyst, comprising:

[0009] The polystyrene resin and acrylic acid are uniformly mixed in a mass ratio of 1:0.5 to 1:2, and then placed in a reactor to carry out a carboxylation reaction at a temperature of 80°C-150°C to generate a carboxylated polystyrene resin catalyst with catalytic activity.

[0010] A fourth aspect of the embodiments of the present invention provides a method for preparing diethylene glycol dimethacrylate, comprising:

[0011] The solid acid catalyst is loaded into a pervaporation membrane reactor, and raw materials, solvents and additives are introduced into the reactor to allow the raw materials to undergo an ester exchange reaction under the action of the solid acid catalyst. After the reaction is completed, the product is separated and purified to obtain diethylene glycol dimethacrylate;

[0012] The raw materials are ethylene glycol compounds and acrylic acid compounds.

[0013] As a preferred technical solution, the glycol compound is diethylene glycol, with a mass fraction of 10 to 40 parts;

[0014] The acrylic compound is methacrylic acid, with a mass fraction of 25 parts to 100 parts;

[0015] The solvent is cyclohexane, with a mass fraction of 5 to 20 parts;

[0016] The auxiliary agent is hydroquinone, and the mass fraction is 1-2 parts.

[0017] As a preferred technical solution, the material of the pervaporation membrane in the pervaporation membrane reactor is polydimethylsiloxane or polyvinyl alcohol.

[0018] As a preferred technical solution, the temperature of the transesterification reaction is 95°C-100°C, the reaction pressure is 0.1MPa-0.5MPa, and the reaction time is 3h-12h.

[0019] As a preferred technical solution, the temperature of the transesterification reaction is 100°C-150°C, the reaction pressure is 0.1MPa-0.5MPa, and the reaction time is 3h-12h.

[0020] As a preferred technical solution, the separation and purification steps include one or more combinations of distillation, extraction, and crystallization.

[0021] By means of the above technical scheme, the present invention provides a solid acid catalyst and a preparation method thereof, and a preparation method of diethylene glycol dimethacrylate. It has at least the following beneficial effects:

[0022] By adopting this method, diethylene glycol dimethacrylate can be efficiently prepared in a permeation vaporization membrane reactor using a solid acid catalyst, which has the advantages of simple operation, high reaction efficiency, high product purity, etc., and the solid acid catalyst can be recycled after the reaction, effectively reducing production costs and reducing environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application:

[0024] FIG. 1 is a flow chart of the synthesis process of an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The present invention provides a solid acid catalyst, which comprises -[CH2-CH(C6H5)-CH2-R] n -, wherein R represents an acidic functional group, such as a sulfonic acid group or a carboxylic acid group, and n represents the number of repeating units. The catalyst is a polymer resin solid acid and has the ability to catalyze esterification reactions.

[0027] The diethylene glycol dimethacrylate prepared by the solid acid catalyst has high purity, and the solid acid catalyst can be recycled after the reaction, thereby effectively reducing production costs and reducing environmental pollution.

[0028] Furthermore, the present invention also provides a method for preparing diethylene glycol dimethacrylate, comprising the following steps:

[0029] Step 1: using a polystyrene skeleton as a carrier, introducing an acidic functional group on its benzene ring to prepare an acidic functionalized polystyrene resin as a solid acid catalyst, wherein the catalyst is a polymer resin solid acid having the ability to catalyze an esterification reaction;

[0030] Step 2: loading a solid acid catalyst into a fixed bed pervaporation membrane reactor to remove excess water during the reaction, introducing ethylene glycol compounds and acrylic acid compounds as raw materials into the reactor, adding solvents and additives, and controlling the reaction temperature and pressure to allow the raw materials to undergo an ester exchange reaction under the action of the solid acid catalyst. During the reaction, the hydrophilic pervaporation membrane continuously separates the generated water to maintain the reaction balance. After the reaction is completed, the product is separated and purified to obtain diethylene glycol dimethacrylate;

[0031] The pervaporation membrane reactor uses membrane materials that are selectively permeable to water, such as polydimethylsiloxane (PDMS), polyvinyl alcohol (PVA), etc.

[0032] Glycol compounds include ethylene glycol, diethylene glycol, etc., and acrylic compounds include acrylic acid, methacrylic acid, etc.;

[0033] Step three, after the reaction is completed, the catalyst is cleaned, inspected and screened, and the active catalyst is put back into the reactor for use.

[0034] Next, the preparation method of the solid acid catalyst and the preparation method of diethylene glycol dimethacrylate are described in conjunction with FIG. 1 and specific examples.

[0035] Embodiment 1

[0036] A method for preparing a solid acid catalyst: chloromethyl polystyrene resin is selected as a starting material, and the chloromethyl polystyrene resin is mixed with concentrated sulfuric acid at a mass ratio of 1:5 and placed in a reaction kettle. The sulfonation temperature is controlled to be 160°C and the sulfonation time is 8 hours to carry out a sulfonation reaction to obtain a sulfonated polystyrene resin solid acid catalyst with catalytic activity. The reaction conditions are controlled, and the main product finally obtained is -[CH2-CH(C6H5)-CH2-SO3H] n -, where -CH2-CH(C6H5)- is the main chain of polystyrene, and some hydrogen atoms on it are replaced by sulfonic acid groups -SO3H to obtain catalytic activity.

[0037] Embodiment 2

[0038] The only difference between this embodiment and the first embodiment is that the mass ratio of chloromethyl polystyrene resin to concentrated sulfuric acid is 1:20, the reaction temperature is 100° C., and the reaction time is 1 h.

[0039] The products of the reactions of Example 1 and Example 2 were sampled, and the content of sulfonated polystyrene resin in the products was measured to obtain Table 1.

[0040] Table 1: Embodiment 1 Embodiment 2 Sulfonated polystyrene resin content in catalyst (%) 86 85

[0041] It can be seen from Table 1 that increasing the content of concentrated sulfuric acid, the reaction temperature and the reaction time in the reaction can make the sulfonation reaction more complete, thereby increasing the content of sulfonated polystyrene resin in the reaction product.

[0042] Embodiment 3

[0043] A method for preparing a solid acid catalyst: a polystyrene resin is selected as a starting material, and a carboxylated polystyrene resin solid acid catalyst is prepared by a carboxylation reaction. A commercially available polystyrene resin is selected, and an appropriate amount of acrylic acid or other suitable carboxylating agent is prepared. The polystyrene resin and acrylic acid are mixed evenly at a mass ratio of 1:0.5, and then placed in a reactor. A carboxylation reaction is carried out at a temperature of 150°C. The reaction time is 14 hours to ensure that the carboxylating agent fully reacts with the polystyrene resin to generate a carboxylated polystyrene resin catalyst with catalytic activity. The reaction conditions are controlled so that the final product includes no less than 85% of -[CH2-CH(C6H5)-CH2-CH(COOH)] n -, in which some hydrogen atoms on the polystyrene main chain -CH2-CH(C6H5)- are replaced by carboxyl groups -COOH. The introduction of carboxyl groups gives the resin catalytic activity.

[0044] Embodiment 4

[0045] The only difference between this embodiment and the fifth embodiment is that the mass ratio of polystyrene resin to acrylic acid is 1:2, the reaction temperature is 80° C., and the reaction time is 8 h.

[0046] The product of the reaction of Example 3 and Example 4 was sampled, and the content of the carboxylated polystyrene resin in the product was measured to obtain Table 2.

[0047] Table 2: Embodiment 3 Embodiment 4 Carboxylated polystyrene resin content in catalyst (%) 85 85

[0048] Embodiment 5

[0049] A method for preparing diethylene glycol dimethacrylate comprises the following steps: using a pervaporation membrane fixed bed reactor, and loading the solid acid catalyst prepared in Example 1 into the reactor. Cyclohexane, methacrylic acid, hydroquinone and diethylene glycol are introduced into the reactor as reaction raw materials, and the mass fraction ratio thereof is 5:25:1:10. The reaction temperature is set to 150°C and the reaction pressure is set to 0.5 MPa, so that the raw materials undergo an ester exchange reaction under the action of the catalyst, and the reaction time is 12 hours. The generated water is removed in time through the pervaporation membrane. After the reaction is completed, the reaction mixture is distilled and separated to obtain a crude diethylene glycol dimethacrylate. The crude product is further subjected to purification steps such as extraction and crystallization to remove impurities, so as to obtain a high-purity diethylene glycol dimethacrylate product.

[0050] Recycling of solid acid catalysts: After the reaction is completed, the catalyst is cleaned, inspected and screened, and the active catalyst is put back into the reactor for use.

[0051] Embodiment 6

[0052] The only difference between this embodiment and embodiment 7 is that the solid acid catalyst prepared in embodiment 3 is loaded into a reactor for reaction.

[0053] Embodiment 7

[0054] The only difference between this embodiment and the fifth embodiment is that the mass ratio of cyclohexane, methacrylic acid, hydroquinone and diethylene glycol is 20:100:2:40, the reaction temperature is 95° C., the reaction pressure is 0.1 MPa, and the reaction time is 3 hours.

[0055] Embodiment 8

[0056] The only difference between this embodiment and the seventh embodiment is that the solid acid catalyst prepared in the third embodiment is loaded into the reactor for reaction.

[0057] Comparative Example 1

[0058] The difference between this comparative example and Example 5 is that concentrated sulfuric acid is used as a catalyst for the reaction.

[0059] Comparative Example 2

[0060] The difference between this comparative example and Example 7 is that concentrated sulfuric acid is used as a catalyst for the reaction.

[0061] For Examples 5 to 8, and Comparative Examples 1 and 2, the conversion efficiency of the reaction raw materials was calculated by measuring the reaction water yield, and the content of diethylene glycol dimethacrylate in the product was sampled and analyzed to obtain Table 3.

[0062] Table 3: Reaction water rate (%) Diethylene glycol dimethacrylate content (%) Catalyst recovery rate (%) Embodiment 5 94.8 96.1 99.9 Embodiment 6 93.6 95.8 99.9 Embodiment 7 93.5 95.8 99.9 Embodiment 8 93.2 95.6 99.9 Comparative Example 1 92.9 94.8 0 Comparative Example 2 92.1 94.8 0

[0063] It can be seen from Table 3 that the catalytic effect of solid acid catalysts is significantly improved compared with traditional liquid acid catalysts, the solid acid catalyst has a high recovery rate, and can be recycled repeatedly.

[0064] Through the above specific implementation methods, the present invention successfully prepares an efficient and environmentally friendly solid acid catalyst, and is successfully applied to the preparation process of diethylene glycol dimethacrylate. The prepared diethylene glycol dimethacrylate can be used in the fields of coatings, adhesives, resin modifiers and polymer resin preparation. The method has the advantages of simple operation, low cost, and high product purity, and is expected to be promoted and applied in actual production. The above implementation method is a specific example of the present invention, which is intended to illustrate the process of preparing diethylene glycol dimethacrylate monomer by solid acid catalyst. However, the protection scope of the present invention is not limited to the above specific conditions and steps. Any adjustment, improvement, replacement, combination or simplification of the conditions, raw materials, steps or processes in the implementation method without violating the basic spirit and principles of the present invention are regarded as equivalent implementation methods of the present invention and are also protected by the present invention.

[0065] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A solid acid catalyst, characterized in that The solid acid catalyst comprises not less than 85% of -[CH2-CH(C6H5)-CH2-R] n -, wherein R is a sulfonic acid group or a carboxylic acid group, and n represents the number of repeating units.

2. The method for preparing the solid acid catalyst according to claim 1, characterized in that: include: Chloromethyl polystyrene resin and concentrated sulfuric acid are mixed in a mass ratio of 1:5 to 1:20, placed in a reaction kettle, and the sulfonation temperature is controlled to be 100° C.-160° C., and the sulfonation time is 1 h-8 h to carry out a sulfonation reaction to obtain a sulfonated polystyrene resin solid acid catalyst with catalytic activity.

3. The method for preparing the solid acid catalyst according to claim 1, characterized in that: include: The polystyrene resin and acrylic acid are uniformly mixed in a mass ratio of 1:0.5 to 1:2, and then placed in a reactor to carry out a carboxylation reaction at a temperature of 80°C-150°C to generate a carboxylated polystyrene resin catalyst with catalytic activity.

4. A method for preparing diethylene glycol dimethacrylate, characterized in that: include: The solid acid catalyst according to any one of claims 1 to 3 is loaded into a pervaporation membrane reactor, and raw materials, solvents and additives are introduced into the reactor to allow the raw materials to undergo an ester exchange reaction under the action of the solid acid catalyst, and after the reaction is completed, the product is separated and purified to obtain diethylene glycol dimethacrylate; The raw materials are ethylene glycol compounds and acrylic acid compounds.

5. The method for preparing diethylene glycol dimethacrylate according to claim 4, characterized in that: The glycol compound is diethylene glycol, with a mass fraction of 10 to 40 parts; The acrylic compound is methacrylic acid, with a mass fraction of 25 parts to 100 parts; The solvent is cyclohexane, with a mass fraction of 5 to 20 parts; The auxiliary agent is hydroquinone, and the mass fraction is 1-2 parts.

6. The method for preparing diethylene glycol dimethacrylate according to claim 4, characterized in that: The material of the pervaporation membrane in the pervaporation membrane reactor is polydimethylsiloxane or polyvinyl alcohol.

7. The method for preparing diethylene glycol dimethacrylate according to claim 4, characterized in that: The temperature of the transesterification reaction is 95° C.-100° C., the reaction pressure is 0.1 MPa-0.5 MPa, and the reaction time is 3 h-12 h.

8. The method for preparing diethylene glycol dimethacrylate according to claim 4, characterized in that: The temperature of the transesterification reaction is 100° C.-150° C., the reaction pressure is 0.1 MPa-0.5 MPa, and the reaction time is 3 h-12 h.

9. The method for preparing diethylene glycol dimethacrylate according to claim 4, characterized in that: The separation and purification steps include one or more combinations of distillation, extraction and crystallization.

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