Metal-modified resin catalyst, preparation and use thereof in acrylic hydration

Abstract

The present application relates to a kind of metal modified ion exchange resin catalyst and its application in catalyzing 3-hydroxypropionic acid of acrylic acid hydration, the preparation method of catalyst includes: (1) metal ion exchange and (2) low-temperature reduction.The present application introduces suitable content of metal into catalyst, can adsorb the intermediate of acrylic acid polymerization reaction, protects active component for catalyzing hydration reaction, to improve the selectivity and reaction stability of 3-hydroxypropionic acid.The preparation condition of catalyst is mild, process is stable and controllable.The prepared catalyst has the advantages such as high activity, strong anti-polymerization ability, good stability etc..

Description

TECHNICAL FIELD

[0001] The present application relates to a catalytic method for preparing 3-hydroxypropionic acid by hydrating acrylic acid, and in particular to a catalytic hydration method for acrylic acid and water on a metal-modified ion exchange resin. BACKGROUND

[0002] 3-hydroxypropionic acid is a widely used chemical raw material, which can be used as an intermediate for fine chemicals and is also a key monomer for synthesizing poly-3-hydroxypropionic acid (P3HP). In recent years, with the implementation of the plastic reduction order, polyhydroxyalkanoates (PHAs) have attracted increasing attention from the international community. Polyhydroxyalkanoates (PHAs) have become a research hotspot in recent years due to their excellent biodegradability. Among them, poly-3-hydroxypropionic acid (P3HP) exhibits excellent properties in terms of hardness, tensile strength, ductility, and biocompatibility, and has potential application value.

[0003] Currently, the reported synthesis methods of 3-hydroxypropionic acid are mainly biological methods. However, the biological fermentation process is time-consuming, low-yield, and complex in separation and purification process, making it difficult to produce on a large scale. Chemical synthesis of 3-hydroxypropionic acid includes beta-propiolactone hydrolysis, beta-hydroxypropionitrile acidification, 3-hydroxypropionaldehyde oxidation, vinyl acetate carbonylation, propylene alcohol oxidation, and acrylic acid hydration. Among them, the acrylic acid hydration method has relatively mild reaction conditions and easy-to-control operation conditions. There are few reports on the preparation of 3-hydroxypropionic acid by acrylic acid hydration. Patent CN102746141A reports a method for preparing 3-hydroxypropionic acid by catalyzing acrylic acid hydration with inorganic acid, molecular sieve, and resin. In a tank reactor, 3-hydroxypropionic acid is prepared by reacting at 60-280℃ for 1-24h. Patent CN110981718B uses acid-modified beta-type molecular sieve as a catalyst, which can reduce the hydration reaction temperature of acrylic acid, reduce the selectivity of by-products, and improve the yield of 3-hydroxypropionic acid. Patent CN113461512A reports a method for preparing 3-hydroxypropionic acid by catalyzing acrylic acid hydration with saturated organic acid. In the currently reported technologies, there are problems such as low efficiency and existence of side reactions. In the process of acrylic acid hydration reaction, the main side reaction is the self-polymerization of acrylic acid under high-temperature strong acid conditions.

[0004] The present application develops a metal-modified ion exchange resin catalyst and its application method in catalyzing acrylic acid hydration to prepare 3-hydroxypropionic acid. By introducing a suitable amount of metal into the ion exchange resin catalyst, the intermediate of the acrylic acid polymerization reaction can be adsorbed, and the active component for catalyzing hydration reaction can be protected, thereby improving the selectivity and reaction stability of 3-hydroxypropionic acid. SUMMARY

[0005] The present application aims at the above-mentioned problems existing in the prior art, and provides a high-efficiency catalyst for preparing 3-hydroxypropionic acid through continuous hydration of acrylic acid, which can improve hydration reaction efficiency, inhibit side reactions, and improve product selectivity.

[0006] The technical scheme is as follows:

[0007] The preparation method of the acrylic acid hydration 3-hydroxypropionic acid catalyst provided by the present application comprises the following steps:

[0008] (1) Metal ion exchange: the ion exchange resin is added into an aqueous solution of metal chloride, and stirred and refluxed at a certain temperature; after cooling to room temperature, the obtained product is washed with deionized water and ethanol in sequence, and dried to obtain the metal ion exchanged resin;

[0009] (2) Low-temperature reduction: the metal ion exchanged resin is added into a reducing agent solution, and stirred and reacted; after washing with deionized water and ethanol in sequence, the obtained product is vacuum dried to obtain the acrylic acid hydration 3-hydroxypropionic acid catalyst.

[0010] Preferably, in step (1), the metal salt is NiCl2·6H2O, and the concentration is 0.05-0.5 mol / L; the solid-liquid ratio of the resin and the metal salt solution is 1:10-1:20; the reaction temperature is 50-90℃, and the reflux time is 4-8 h; after cooling to room temperature, the obtained product is washed with deionized water until no chloride ions are left, and then washed with anhydrous ethanol; the obtained product is vacuum dried at 50-100℃ for 6-12 h to obtain the metal ion exchanged resin.

[0011] Preferably, in step (2), the reducing agent is a sodium borohydride aqueous solution, and the concentration is 0.2-2.0 mol / L; the solid-liquid ratio is 1:10-1:20; the reaction time is 1-4 h; after the reaction is completed, the obtained product is washed with deionized water and anhydrous ethanol in sequence; the obtained product is dried at 80-120℃ for 6-12 h to obtain the metal modified exchange resin, wherein the metal content is 0.1-1 wt%.

[0012] The application of a solid superacid catalyst for preparing 3-hydroxypropionic acid through hydration of acrylic acid in the reaction of preparing 3-hydroxypropionic acid through hydration of acrylic acid.

[0013] Preferably, a fixed bed reactor is used, the raw material is an aqueous solution of acrylic acid, and the mass concentration is 25-50%; the polymerization inhibitor is p-methoxyphenol, and the mass ratio of the polymerization inhibitor to acrylic acid is 0.05-0.2%; the reaction temperature is 120-180℃; the reaction pressure is 0.5-1.5 MPa; the mass space velocity is 0.75-2 h -1 .

[0014] The present application introduces metal into the catalyst in a suitable amount, which can adsorb the intermediate of acrylic acid polymerization reaction, protect the active component for catalyzing hydration reaction, thereby improving the selectivity and reaction stability of 3-hydroxypropionic acid. The catalyst is prepared under mild conditions, and the process is stable and controllable. The prepared catalyst has the advantages of high activity, strong polymerization resistance and good stability.

[0015] Beneficial technical effects

[0016] 1. The present application prepares an acrylic acid hydration catalyst by ion exchange and low-temperature reduction, introduces metal in a suitable amount, which can adsorb the intermediate of acrylic acid polymerization reaction, protect the active component for catalyzing hydration reaction, thereby improving the selectivity and reaction stability of 3-hydroxypropionic acid.

[0017] 2. The catalyst preparation process is simple, controllable and easy to operate, and has a wide application prospect. DETAILED DESCRIPTION

[0018] In order to further illustrate the present application, several specific implementation cases are given below, but the present application is not limited to these examples.

[0019] Example 1

[0020] (1) Metal ion exchange: weigh 1.19 g of NiCl2·6H2O and dissolve it in 50 mL of deionized water, add 5.0 g of ion exchange resin Amberlyst-15, stir at 80℃ for 4 h, then cool to room temperature, wash with deionized water until no chloride ions are left, then wash with anhydrous ethanol, and dry at 120℃ for 12 h to obtain the Ni 2+ exchanged resin precursor;

[0021] (2) Low-temperature reduction: weigh 1.89 g of sodium borohydride and dissolve it in 50 mL of deionized water, add the precursor prepared in step (1), react for 2 h, then wash with deionized water and anhydrous ethanol in turn, and dry at 60℃ under vacuum for 12 h to obtain the metal-modified exchange resin, which is denoted as catalyst 1;

[0022] (3) Catalyst evaluation: carried out in a fixed bed tubular reactor, the raw material is a 50% mass concentration aqueous solution, the mass concentration of the polymerization inhibitor hydroquinone is 0.1%, the reaction temperature is 180℃, the reaction pressure is 1.0 MPa, the mass space velocity is 1.0 h -1 ; the product is analyzed by high performance liquid chromatography for composition and content, and the conversion rate of acrylic acid and the selectivity of 3-hydroxypropionic acid are calculated.

[0023] Comparative Example 1

[0024] Comparative Example 1 was the same as Example 1 except that the catalyst was an unmodified ion exchange resin, designated Catalyst 2. The catalyst evaluation conditions were the same as Example 1.

[0025] Example 2: Different ion exchange conditions

[0026] Example 2 was the same as Example 1 except that in Step (1) 1.18 g of NiCl2-6H2O was dissolved in 100 mL of deionized water and the reaction was stirred at reflux at 50°C for 8 h, designated Catalyst 3. The catalyst evaluation conditions were the same as Example 1.

[0027] Example 3: Different ion exchange conditions

[0028] Example 3 was the same as Example 1 except that in Step (1) 8.91 g of NiCl2-6H2O was dissolved in 75 mL of deionized water and the reaction was stirred at reflux at 90°C for 2 h, designated Catalyst 4. The catalyst evaluation conditions were the same as Example 1.

[0029] Example 4: Different low temperature reduction conditions

[0030] Example 4 was the same as Example 1 except that in Step (2) 2.5 g of hydrazine hydrate was dissolved in 50 mL of deionized water, designated Catalyst 5. The catalyst evaluation conditions were the same as Example 1.

[0031] Example 5: Different low temperature reduction conditions

[0032] Example 5 was the same as Example 1 except that in Step (2) 0.5 g of hydrazine hydrate was dissolved in 50 mL of deionized water and the reduction was carried out for 4 h, designated Catalyst 6. The catalyst evaluation conditions were the same as Example 1.

[0033] Example 6: Different low temperature reduction conditions

[0034] Example 6 was the same as Example 1 except that in Step (2) 1.54 g of sodium borohydride was dissolved in 50 mL of deionized water, designated Catalyst 7. The catalyst evaluation conditions were the same as Example 1.

[0035] Example 7: Different low temperature reduction conditions

[0036] Example 7 was the same as Example 1 except that in Step (2) 0.31 g of sodium borohydride was dissolved in 50 mL of deionized water and the reduction was carried out for 1 h, designated Catalyst 8. The catalyst evaluation conditions were the same as Example 1.

[0037] Example 8: Different exchange metal species

[0038] Example 8 is the same as Example 1 in process and conditions, except that in step (1) 0.85 g CuCl2.2H2O was weighed into 50 mL deionized water, and in step (2) 0.38 g sodium borohydride was weighed into 50 mL deionized water, and was recorded as catalyst 9. The catalyst evaluation conditions were the same as Example 1.

[0039] Example 9: Different exchange metal species

[0040] Example 9 is the same as Example 1 in process and conditions, except that in step (1) 1.35 g FeCl3.6H2O was weighed into 50 mL deionized water, and in step (2) the reduction time was 4 h, and was recorded as catalyst 10. The catalyst evaluation conditions were the same as Example 1.

[0041] Example 10: Different exchange metal species

[0042] Example 10 is the same as Example 1 in process and conditions, except that in step (1) 1.19 g CoCl2.6H2O was weighed into 50 mL deionized water, and in step (2) 3.78 g sodium borohydride was weighed into 50 mL deionized water, and was recorded as catalyst 11. The catalyst evaluation conditions were the same as Example 1.

[0043] The following table lists the reaction evaluation results of the catalysts prepared by the method described in the present application

[0044] Example Acrylic acid conversion / % Dimer selectivity / % 3-hydroxypropionic acid selectivity / % Example 1 81.1 7.8 84.2 Comparative Example 1 61.6 15.2 67.8 Example 2 70.5 12.8 71.6 Example 3 80.1 8.3 82.8 Example 4 80.3 8.1 82.6 Example 5 76.1 9.3 72.9 Example 6 79.8 8.6 80.3 Example 7 75.1 9.4 71.3 Example 8 80.9 8.0 83.9 Example 9 77.5 10.1 81.8 Example 10 77.8 9.9 82.3

[0045] From Example 1 and Comparative Example 1, it can be seen that the metal-modified ion exchange resin is beneficial to increasing the conversion of acrylic acid and the selectivity of 3-hydroxypropionic acid, and inhibiting the generation of acrylic acid dimers; from Examples 1-7, it can be seen that the modification conditions of 1 are optimal; from Examples 1, 8-10, it can be seen that Ni is optimal, and Cu, Co and Fe decrease in turn.

Claims

1. Use of a metal-modified ion exchange resin catalyst in catalyzing hydration of acrylic acid to prepare 3-hydroxypropionic acid, comprising a metal promoter and an ion exchange resin, wherein the content of the metal promoter is 0.05-5 wt%; the rest is the ion exchange resin, and the ion exchange resin used is a macroporous strong acid ion exchange resin. Preparation of the catalyst comprises the following steps: (1) Metal ion exchange: the ion exchange resin is added into an aqueous solution of metal chloride, and stirred to reflux, and then cooled to room temperature, and then washed with deionized water and ethanol in sequence, and dried to obtain a metal ion exchanged resin; the metal chloride is one or two or more of NiCl2·6H2O, CuCl2·2H2O, FeCl3·6H2O or CoCl2·6H2O; (2) Low-temperature reduction: the metal ion exchanged resin is added into a reducing agent solution, and stirred to react, and then washed with deionized water and ethanol in sequence, and dried to obtain a catalyst for hydration of acrylic acid to prepare 3-hydroxypropionic acid.

2. The use according to claim 1, wherein the ion exchange resin used is one or two or more of macroporous strong acid ion exchange resins of types D001, HND58 and Amberlyst-15.

3. The use according to claim 1, wherein the content of the metal promoter is 0.1-1 wt%.

4. The use according to claim 1, wherein in step (1), the concentration of the metal chloride is 0.01-1 mol / L; the solid-liquid ratio of the ion exchange resin to the aqueous solution of the metal chloride is 1:5-1:50 g:mL; the reaction temperature is 50-90 ℃, and the reflux time is 2-10 h; after cooling to room temperature, the ion exchange resin is washed with deionized water until no chloride ions are left, and then washed with anhydrous ethanol; and the ion exchange resin is dried at 80-120 ℃ for 6-12 h to obtain the metal ion exchanged resin.

5. The use according to claim 1, wherein in step (2), the reducing agent is one or two or more of aqueous solutions of sodium borohydride, hydrazine hydrate or ammonia borane; the concentration of the reducing agent is 0.05-5 mol / L; the solid-liquid ratio of the ion exchange resin to the aqueous solution of the metal chloride is 1:5-1:50 g:mL; the reaction time is 0.5-8 h; after the reaction is completed, the ion exchange resin is washed with deionized water and anhydrous ethanol in sequence; and the ion exchange resin is vacuum dried at 50-100 ℃ for 6-12 h to obtain the metal-modified ion exchange resin, wherein the content of the metal is 0.05-5 wt%.

6. The use according to claim 1, wherein the metal-modified ion exchange resin catalyst is used in catalyzing hydration of acrylic acid to prepare 3-hydroxypropionic acid.

7. The use according to claim 6, wherein the metal-modified ion exchange resin catalyst is used in catalyzing hydration of acrylic acid to prepare 3-hydroxypropionic acid. ​ ​ ​ ​ ​ The fixed bed reactor is used, the raw material is the water solution of acrylic acid with the mass concentration of 15-75%; the polymerization inhibitor is one or several of hydroquinone, p-methoxy phenol and phenothiazine, the mass ratio of the polymerization inhibitor to acrylic acid is 0.01-1%; the reaction temperature is 100-200 DEG C; the reaction pressure is 0.1-2 MPa; the mass space velocity is 0.5-5 h -1 . ​ The fixed bed reactor is used, the raw material is the aqueous solution of acrylic acid, the mass concentration is 25-50%; the polymerization inhibitor is one or several of hydroquinone, p-methoxy phenol and phenothiazine, the mass ratio of the polymerization inhibitor to acrylic acid is 0.05-0.2%; the reaction temperature is 120-180 DEG C; the reaction pressure is 0.5-1.5 MPa; the mass space velocity is 0.75-2 h -1 .