Synthesis method and application of composite modified Y-type molecular sieve

Abstract

The invention relates to the technical field of molecular sieve modification, in particular to a synthesis method of a composite modified Y-type molecular sieve. The composite modified Y-type molecular sieve is obtained by taking the Y-type molecular sieve as a parent, firstly carrying out acid treatment and then carrying out metal modification, and the composite modified Y-type molecular sieve shows good catalytic performance in a ring-opening addition reaction of acrylic acid and tetrahydrofuran, promotes synthesis of 4-hydroxybutyl acrylate, improves the selectivity of a main product, inhibits a polymerization reaction and improves the catalytic activity of the main product. The production of double esterification products is avoided, the subsequent separation process is simplified, and the investment cost is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of molecular sieve modification, and in particular to a synthesis method of a composite modified Y-type molecular sieve and application thereof. Background Art

[0002] Hydroxyl acrylate is a type of acrylic ester monomer containing a hydroxyl functional group. It has high reactivity because of its highly reactive hydroxyl group and double bond that can react with a variety of crosslinking agents. It can be used in water-based, solvent-based and UV curing systems, and has good flexibility and chemical resistance. Hydroxyl acrylate is widely used in coatings, adhesives, plastic modification and other fields due to its excellent performance. It is expected that by 2025, the global hydroxy acrylate market will reach a higher level, with an annual compound growth rate of about 4.29%. Among them, the demand in coatings, adhesives and plastics will continue to grow, and the application in emerging fields such as high-performance materials, biomedicine and electronic packaging will continue to expand. As a high-performance and environmentally friendly material, hydroxy acrylate has a good development prospect. Among them, 4-hydroxybutyl acrylate has high hydroxyl reactivity and flexibility. The longer chain segments in its molecular structure make it show higher degrees of freedom in cross-linking reactions. In the field of coatings, it can be used for automotive repair paints, architectural coatings and UV-curing coatings, and has excellent weather resistance, scratch resistance and flexibility; in the field of adhesives, it can be used for high-performance pressure-sensitive adhesives and structural adhesives; in plastic modification, it can improve the flexibility and impact resistance of plastics. At present, the production routes of 4-hydroxybutyl acrylate mainly include ester exchange method, direct esterification method and ring-opening addition method. For the ester exchange method and direct esterification method, it is inevitable to encounter the problem of separation of monoesters and diesters; for the ring-opening addition method, refer to the synthesis routes of hydroxyethyl methacrylate (HEMA) and hydroxypropyl methacrylate (HPMA), as shown in Formula 1 and Formula 2; 4-hydroxybutyl acrylate is synthesized by ring-opening addition with acrylic acid and tetrahydrofuran as raw materials, as shown in Formula 3. After the reaction, the product is single, and the boiling points of the raw materials and products are very different, so distillation can easily achieve separation, greatly reducing equipment investment, and has absolute advantages over the first two methods.

[0003]

[0004] Catalysts play an extremely important role in the esterification addition route. In the ring-opening addition reaction of acrylic acid and tetrahydrofuran to synthesize 4-hydroxybutyl acrylate, since the reaction is an acid-catalyzed reaction, too strong acidity will promote the ring-opening polymerization of tetrahydrofuran. Therefore, we need a catalyst with adjustable acidity to be used in the ring-opening addition reaction of acrylic acid and tetrahydrofuran to synthesize 4-hydroxybutyl acrylate. Summary of the invention

[0005] The invention provides a method for synthesizing a composite modified Y-type molecular sieve. A novel molecular sieve with suitable acid properties is obtained by acid-modifying and metal-modifying the Y-type molecular sieve. The composite modified Y-type molecular sieve is used in the ring-opening addition reaction of acrylic acid and tetrahydrofuran to prepare 4-hydroxybutyl acrylate, thereby improving the selectivity of 4-hydroxybutyl acrylate and avoiding the generation of a double esterification product BDDA.

[0006] In a first aspect, the method for synthesizing the composite modified Y-type molecular sieve of the present invention comprises acid-modifying the Y-type molecular sieve and then metal-modifying the Y-type molecular sieve.

[0007] Specifically, the synthesis method of the composite modified Y-type molecular sieve of the present invention comprises the following steps:

[0008] (1) Acid modification: The Y-type molecular sieve is mixed with an acid solution for acid treatment, followed by washing and drying;

[0009] (2) Metal modification: The acid-modified molecular sieve obtained in step (1) is mixed with a metal salt solution, and then washed and dried to obtain a composite modified Y-type molecular sieve.

[0010] Preferably, the Y-type molecular sieve in step (1) is a commercial molecular sieve, and the silicon-aluminum ratio of the Y-type molecular sieve is 9-12.

[0011] Preferably, the acid in step (1) is one or more of sulfuric acid, acetic acid, citric acid, phosphoric acid, and nitric acid, the concentration of the acid solution is preferably 0.05-3 mol / L, and the solid-liquid ratio of the Y-type molecular sieve to the acid solution is preferably 1:2-8, preferably 1:2-5.

[0012] Preferably, in step (1), the Y-type molecular sieve is evenly mixed with the acid solution and then stirred at a temperature of 40-90°C (preferably 45-85°C) for 0.5-8h (preferably 2-6h) for acid treatment to obtain an acid-modified molecular sieve, which is then cooled to room temperature and washed with deionized water and then dried.

[0013] Specifically, the product is washed with deionized water until the pH value of the washing solution is 7-8, and the drying is preferably carried out in an oven at a temperature of 80-120° C. for a drying time of 8-12 hours.

[0014] Preferably, the metal salt in step (2) includes one or more of ferric nitrate, cobalt nitrate, nickel nitrate and chromium nitrate; the concentration of the metal salt solution is 0.05-3 mol / L; the solid-liquid ratio of the acid-modified molecular sieve to the metal salt solution is 1:2-8, preferably 1:2-5.

[0015] Preferably, in step (2), after the acid-modified molecular sieve and the metal salt solution are uniformly mixed, they are stirred at 40-90° C. (preferably 50-80° C.) for 0.5-8 h (2-5 h) for metal modification treatment, and after cooling to room temperature, they are washed and dried.

[0016] Specifically, deionized water is used for washing until the pH value of the washing solution is 7-8, and then the washing is dried in an oven at a temperature of 80-120° C. for 8-12 hours.

[0017] In a second aspect, the composite modified Y-type molecular sieve of the present invention is used in the preparation of hydroxybutyl acrylate by the ring-opening addition reaction of acrylic acid and tetrahydrofuran.

[0018] Specifically, the ring-opening addition reaction of acrylic acid and tetrahydrofuran to prepare 4-hydroxybutyl acrylate can adopt existing technologies, such as CN119456023A, CN119330824A, etc.

[0019] Preferably, in the ring-opening addition reaction of the present invention, the molar ratio of acrylic acid to tetrahydrofuran is 1:1.1-3.0, preferably 1:1.5-2; the reaction temperature is 30-60°C, and the reaction pressure is 1-3MPaG.

[0020] Preferably, the amount of the composite modified Y-type molecular sieve used is 2-6 wt.% of the mass of acrylic acid.

[0021] Optionally, the ring-opening addition reaction is also carried out in the presence of a polymerization inhibitor.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The invention provides a composite modified Y-type molecular sieve. A molecular sieve with suitable acid properties is obtained by acid-modification and metal-modification treatment of the Y-type molecular sieve, which covers the B acid center and adjusts the Brφnsted / Lewis acid center ratio. Under the synergistic effect of B acid and L acid, the composite modified Y-type molecular sieve is used in the reaction of synthesizing 4-hydroxybutyl acrylate by ring-opening addition of acrylic acid and tetrahydrofuran, thereby improving the selectivity of 4-hydroxybutyl acrylate. DETAILED DESCRIPTION

[0024] The following examples will further illustrate the present invention and are intended to help readers better understand the essence of the present invention and the beneficial effects brought about, but should not be construed as any limitation on the practicable scope of the present invention.

[0025] Source of raw materials

[0026] Y-type molecular sieve: Y-type molecular sieve was purchased from Tianjin Nanhua Catalyst Co., Ltd., model NKF-7-4, and the silicon-aluminum molecular ratio was 9-12.

[0027] Test Method

[0028] Gas phase analysis: Shimadzu GC-2010Plus; injection port temperature: 280°C; split ratio: 30:1; chromatographic column: DB-5 (60m×0.25mm×0.25μm); heating program: 50°C for 2 minutes, increase the temperature to 80°C at 5°C / min, maintain for 10 minutes, increase the temperature to 300°C at 15°C / min, maintain for 10 minutes; FID detector temperature: 300°C.

[0029] Example 1

[0030] The Y-type molecular sieve was uniformly mixed with an acetic acid solution with a concentration of 0.05 mol / L at a solid-liquid ratio of 1:3, stirred at 60°C for 2 hours for acid treatment, cooled to room temperature, washed with deionized water until the pH of the washing solution was 7, and dried in an oven at 100°C for 12 hours to obtain a solid, which is the acid-modified Y-type molecular sieve.

[0031] The acid-modified Y-type molecular sieve was then subjected to metal modification. The acid-modified Y-type molecular sieve was evenly mixed with chromium nitrate having a concentration of 0.1 mol / L at a solid-liquid ratio of 1:3, and stirred at 60°C for 2 hours for metal modification. After cooling to room temperature, it was washed with deionized water until the pH of the washing liquid was 7, and then dried in an oven at 100°C for 12 hours to obtain a composite modified Y-type molecular sieve.

[0032] The ring-opening addition process of acrylic acid and tetrahydrofuran adopts an intermittent kettle process, a composite modified Y-type molecular sieve is added into the kettle, the addition amount is 6wt.% of acrylic acid, the reaction temperature is 50°C, the molar ratio of acrylic acid to tetrahydrofuran in the raw material is 1:2, the reaction pressure is 2MPaG, the acrylic acid conversion rate is controlled to be above 99%, and the obtained reaction liquid is subjected to gas phase analysis, the selectivity of the main product 4-hydroxybutyl acrylate (4-HBA) reaches 97%, and the selectivity of 1,4-butanediol diacrylate (BDDA) is 3%.

[0033] Example 2

[0034] The Y-type molecular sieve was uniformly mixed with a phosphoric acid solution with a concentration of 2 mol / L at a solid-liquid ratio of 1:7, stirred at 80°C for 6 hours for acid treatment, cooled to room temperature, washed with deionized water until the pH of the washing solution was 7, and dried in an oven at 100°C for 12 hours to obtain a solid, which was the acid-modified Y-type molecular sieve.

[0035] The acid-modified Y-type molecular sieve was then subjected to metal modification. The acid-modified Y-type molecular sieve was evenly mixed with cobalt nitrate having a concentration of 2 mol / L at a solid-liquid ratio of 1:5, and stirred at 80°C for 2 hours for metal modification. After cooling to room temperature, it was washed with deionized water until the pH of the washing liquid was 7, and then dried in an oven at 100°C for 12 hours to obtain a composite modified Y-type molecular sieve.

[0036] The ring-opening addition process of acrylic acid and tetrahydrofuran adopts an intermittent autoclave process, a composite modified Y-type molecular sieve is added into the autoclave, the addition amount is 5wt.% of acrylic acid, the reaction temperature is 40°C, the molar ratio of acrylic acid to tetrahydrofuran in the raw material is 1:1.5, the reaction pressure is 1.2MPaG, the acrylic acid conversion rate is controlled to be above 99%, and the obtained reaction liquid is subjected to gas phase analysis, the selectivity of the main product 4-hydroxybutyl acrylate (4-HBA) reaches 89%, and the selectivity of 1,4-butanediol diacrylate (BDDA) is 11%.

[0037] Example 3

[0038] The Y-type molecular sieve was uniformly mixed with a sulfuric acid solution with a concentration of 1 mol / L at a solid-liquid ratio of 1:2, stirred at 40°C for 6 hours for acid treatment, cooled to room temperature, washed with deionized water until the pH of the washing solution was 7.5, and dried in an oven at 100°C for 12 hours to obtain a solid, which was the acid-modified Y-type molecular sieve.

[0039] The acid-modified Y-type molecular sieve was then subjected to metal modification. The acid-modified Y-type molecular sieve was evenly mixed with ferric nitrate having a concentration of 0.05 mol / L at a solid-liquid ratio of 1:2, and stirred at 60°C for 5 hours for metal modification. After cooling to room temperature, it was washed with deionized water until the pH of the washing liquid was 7.5, and then dried in an oven at 100°C for 12 hours to obtain a composite modified Y-type molecular sieve.

[0040] The ring-opening addition process of acrylic acid and tetrahydrofuran adopts an intermittent autoclave process, a composite modified Y-type molecular sieve is added into the autoclave, the addition amount is 2wt.% of acrylic acid, the reaction temperature is 50°C, the molar ratio of acrylic acid to tetrahydrofuran in the raw material is 1:1.8, the reaction pressure is 2MPaG, the acrylic acid conversion rate is controlled to be above 99%, and the obtained reaction liquid is subjected to gas phase analysis, the selectivity of the main product 4-hydroxybutyl acrylate (4-HBA) reaches 82%, and the selectivity of 1,4-butanediol diacrylate (BDDA) is 18%.

[0041] Comparative Example 1

[0042] Unmodified Y-type molecular sieve was added into the reactor as a catalyst in an amount of 6 wt.% of acrylic acid content, the molar ratio of acrylic acid to tetrahydrofuran was 1:2, the reaction temperature was 50°C, the reaction pressure was 2 MPaG, the acrylic acid conversion rate was controlled to be above 99%, and the obtained reaction liquid was analyzed. A large amount of macromolecular substances existed in the reaction liquid, the 4-HBA content in the reaction liquid was only 4%, and the 4-HBA synthesis reaction failed to proceed normally.

Claims

1. A method for synthesizing a composite modified Y-type molecular sieve, characterized in that: The steps include: (1) Acid modification: The Y-type molecular sieve is mixed with an acid solution and treated with an acid to obtain an acid-modified molecular sieve; (2) Metal modification: The acid-modified molecular sieve obtained in step (1) is mixed with a metal salt solution, and then washed and dried to obtain a composite modified Y-type molecular sieve.

2. The synthesis method according to claim 1, characterized in that In step (1), the silicon-aluminum ratio of the Y-type molecular sieve is 9-12; And / or: the acid in the acid solution is one or more of sulfuric acid, acetic acid, citric acid, phosphoric acid, and nitric acid, and the concentration of the acid solution is preferably 0.05-3 mol / L.

3. The synthesis method according to claim 2, characterized in that In step (1), the solid-liquid ratio of the Y-type molecular sieve to the acid solution is 1:2-8, preferably 1:2-5.

4. The synthesis method according to claim 2 or 3, characterized in that: In step (1), the acid treatment temperature is 40-90°C, preferably 45-85°C; the acid treatment time is 0.5-8h, preferably 2-6h.

5. The synthesis method according to any one of claims 2 to 4, characterized in that: After the acid treatment in step (1), the acid-modified molecular sieve is washed and dried, preferably until the pH of the washing solution is 7-8, the drying temperature is 80-120° C., and the drying time is 8-12 hours.

6. The synthesis method according to claim 1, characterized in that The metal salt in step (2) includes one or more of ferric nitrate, cobalt nitrate, chromium nitrate and nickel nitrate, and the concentration of the metal salt solution is 0.05-3 mol / L.

7. The synthesis method according to claim 6, characterized in that In step (2), the solid-liquid ratio of the acid-modified molecular sieve to the metal salt solution is 1:2-8, preferably 1:2-5.

8. The synthesis method according to claim 7, characterized in that The metal modification temperature in step (2) is 40-90°C, preferably 50-80°C; the modification time is 0.5-8h, preferably 2-5h.

9. The synthesis method according to any one of claims 6 to 8, characterized in that: Step (2) washing until the pH of the washing solution is 7-8, the drying temperature is 80-120° C., and the drying time is 8-12 hours.

10. Use of the composite modified Y-type molecular sieve according to any one of claims 1 to 9 in the synthesis of 4-hydroxybutyl acrylate by the ring-opening addition method of acrylic acid and tetrahydrofuran; Preferably, the molar ratio of acrylic acid to tetrahydrofuran is 1:1.1-3.0, the reaction temperature is 30-60°C, and the reaction pressure is 1-3MPaG; Preferably, the amount of the composite modified Y-type molecular sieve used is 2-6 wt.% of the mass of acrylic acid.

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