A method for synthesizing tert-butyl (meth)acrylate using a composite metal oxide catalyst

Abstract

The present invention discloses a method for synthesizing tert-butyl (meth)acrylate by using a composite metal oxide catalyst, belonging to the technical field of organic synthesis. In the present invention, a catalyst, an inhibitor, (meth)acrylic acid and isobutene are mixed in a reaction kettle to synthesize tert-butyl (meth)acrylate. The catalyst is a composite oxide WO 3 / Ce x Fe y M z O 2 , wherein M is one or more of Zr, Nb, Sn, Ga, Re, Y, La, Nd, Sm, Er. The inhibitor is a combination of tert-butanol, phenothiazine, p-methoxyphenol, and tert-butylcatechol, and is used in combination with air. The present invention significantly reduces the production cost of tert-butyl acrylate, improves the esterification rate, and effectively prevents the polymerization of raw materials and products during the reaction process. It has the advantages of a simple process route, mild reaction conditions, and easy separation of the catalyst from the raw materials and products.

Description

Technical Field

[0001] The invention belongs to the field of organic synthesis, and particularly relates to a method for synthesizing tert-butyl (meth)acrylate by utilizing a composite metal oxide catalyst. Technical Background

[0002] Tert-butyl acrylate is an extremely important chemical raw material and intermediate. Because of its unique and highly active polar molecules, unsaturated double bonds and carboxylic acid ester (-COOR) structure, it can be derived into many polymer formulas with good performance. The various tert-butyl acrylate polymers prepared have excellent properties such as strong adhesion, good transparency and clear film formation. Therefore, tert-butyl acrylate has excellent chemical and physical properties such as excellent light stability, weather resistance, water resistance, oil resistance, and chemical resistance.

[0003] In the industry, traditional esterification reactions are mostly synthesized by esterification of acrylic acid and tert-butyl alcohol under the catalysis of concentrated sulfuric acid. During the reaction, due to the large steric hindrance of tert-butyl alcohol, the elimination reaction is more inclined to the two competitive reactions of esterification and elimination, and the esterification rate is low. This reaction has many side reactions, the product color is dark, the post-processing process is complicated, the equipment is severely corroded, and the wastewater discharge is large.

[0004] The acid-ene addition method is a widely used method for producing tert-butyl acrylate products. It is a typical green chemical atom economy process. It replaces tert-butyl alcohol with abundant and cheap isobutylene, which not only improves the reaction conversion rate but also reduces production costs. This process uses solid acid catalysts, which, compared with traditional inorganic acids such as concentrated sulfuric acid and sulfonic acid, reduces corrosion to equipment, is easy to separate products, and can be reused.

[0005] Patent CN104276948A discloses an acidic cationic resin catalyst for acid-ene addition reaction, but the catalyst has low activity, rapid deactivation, and low reaction selectivity; Patent CN110950760 A discloses a p-toluenesulfonic acid catalyst for acid-ene addition reaction, but the method uses a homogeneous catalyst, the later separation process is complicated, and the purity of acrylate is not high. In addition, in the production process of tert-butyl acrylate, due to the special structure of the raw materials and products, whether it is a continuous method or an intermittent method, due to its mixing inhomogeneity, polymerization problems have always existed in the reaction system and the refining system. Therefore, research and development of a new catalyst system for rapid and efficient preparation of high-purity tert-butyl acrylate has become an important topic that needs to be studied urgently. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides a method for synthesizing tert-butyl (meth)acrylate by using a composite metal oxide catalyst.

[0007] To achieve the purpose of the present invention, the technical solution provided by the present invention is as follows:

[0008] A method using WO 3 / Ce x Fe y M z O 2 Method for synthesizing tert-butyl (meth)acrylate by using a catalyst, 3 / Ce x Fe y M z O 2 Catalyst, inhibitor, (meth) acrylic acid and isobutylene are mixed in a reaction kettle to synthesize tert-butyl (meth)acrylate, WO 3 / Ce x Fe y M z O 2 In the catalyst, M is one or more of Zr, Nb, Sn, Ga, Re, Y, La, Nd, Sm, and Er.

[0009] Based on the above technical solution, further, CeO 2 with Fe 2 O 3 Total mass, WO 3 The content is 0.1-30%, 0≤x≤1, 0≤y≤1, 0≤z≤1, x+y+z=1.

[0010] Based on the above technical solution, further, CeO 2 with Fe 2 O 3 Total mass, WO 3 The content is 1-20%.

[0011] Based on the above technical solution, further, the inhibitor is used in combination with air, wherein the inhibitor is a combination of tert-butyl alcohol, phenothiazine, p-hydroxyanisole, and tert-butylcatechol, and the mass ratio is 10-15:4-6:2-4:4-6.

[0012] Based on the above technical solution, further, the mass ratio of tert-butyl alcohol, phenothiazine, p-hydroxyanisole and tert-butylcatechol is 12:5:3:5.

[0013] Based on the above technical solution, further, the reaction temperature is 30-60°C, the air pressure is 0.1-5.0MPa, the reaction time is 2-10h, and the stirring rate is 500-1500rpm.

[0014] Based on the above technical solution, further, the molar ratio of (meth)acrylic acid to isobutylene is 0.2:1-5:1.

[0015] Based on the above technical solution, further, the polymerization inhibitor is 0.01-1% of the mass of (meth)acrylic acid.

[0016] Based on the above technical solution, further, the mass of the catalyst is 5-20% of the mass of (meth)acrylic acid.

[0017] Based on the above technical solution, further, the (meth)acrylic acid includes acrylic acid and methacrylic acid; the tert-butyl (meth)acrylate includes tert-butyl acrylate and tert-butyl methacrylate.

[0018] Based on the above technical solution, further, the preparation method of the above catalyst includes the following steps:

[0019] 1) Weigh soluble salts of Ce, Fe and M, add deionized water and stir to dissolve to obtain solution A;

[0020] 2) Weigh soluble salt of W, add deionized water and stir to dissolve to obtain solution B;

[0021] 3) Slowly drop solution A into solution B under stirring, and obtain solution C after dropping;

[0022] 4) Weigh a certain amount of template agent CTAB, add deionized water and stir to dissolve, and slowly drop the obtained solution into solution C. After dropping, continue to stir for 2-6 h;

[0023] 5) Slowly drop the precipitant into the solution obtained in step 4) under stirring until the pH is 9-14, and continue to stir for 2-10 h;

[0024] 6) Transfer the solution obtained in step 5) to a hydrothermal kettle and crystallize at 70-180 °C for 6-96 h;

[0025] 7) After crystallization, centrifuge and wash until there is no chloride ion, then wash with absolute ethanol 1-5 times, and dry in vacuum to obtain a precursor;

[0026] 8) Calcinate the precursor in an air atmosphere at 400-1100 °C for 2-12 h to obtain a composite oxide WO 3 / Ce x Fe y M z O 2 .

[0027] Based on the above technical solution, further, the ratio of the total molar number of the template agent to the metal ions in step 4) is 1:1-1:20.

[0028] Based on the above technical solution, further, the precipitant in step 5) is NH 4 HCO3 , (NH 4 ) 2 CO 3 , Na 2 CO 3 , one or more of NaOH, ammonia water or urea.

[0029] Based on the above technical solution, further, the crystallization temperature in step 6) is 100 - 150 °C, and the crystallization time is 48 - 96 h.

[0030] Based on the above technical solution, further, the calcination temperature in step 8) is 500 - 700 °C, and the calcination time is 4 - 10 h.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1) The catalyst of the present invention is simple to prepare and has good repeatability, and both the reaction esterification rate and selectivity are relatively high;

[0033] 2) The present invention uses a composite oxide as a catalyst, and a special catalytic system composed of a variety of polymerization inhibitors and oxygen-containing nitrogen gas catalyzes the synthesis of tert-butyl (meth)acrylate from (meth)acrylic acid and isobutene, which can significantly improve the esterification rate of (meth)acrylic acid and tert-butyl ester, and effectively prevent the polymerization problem of raw materials and products during the reaction;

[0034] 3) The process of the present invention is simple and environmentally friendly, does not produce waste acid and waste water, does not require waste acid and waste water treatment, is a true atom economic reaction, and reduces production costs. Specific Embodiments

[0035] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0036] Example 1

[0037] Catalyst preparation:

[0038] Weigh 13.05 g of Ce(NO 3 ) 3 ·6H 2 O, 6.08 g of Fe(NO 3 ) 3 ·6H 2Add 100 ml of deionized water and stir to dissolve to obtain solution A; weigh 1.28 g of ammonium metatungstate, add 50 ml of deionized water and stir to dissolve to obtain solution B; slowly add solution A dropwise to solution B with stirring, and obtain solution C after the addition; weigh 4.37 g of template CTAB, add 50 mL of deionized water and stir to dissolve, and slowly add the obtained solution to solution C. After the addition, continue to stir for 4 h; slowly add a precipitating agent which is a mixture of 0.1 mol / l (NH 4 ) 2 CO 3 and ammonia water in equal volume until the pH is 13, and continue to stir for 4 h; transfer the solution to a hydrothermal autoclave with a liner, and crystallize at 120 °C for 72 h; after crystallization, centrifuge and wash repeatedly until there is no chloride ion, and then wash 3 times with a small amount of absolute ethanol; dry in vacuum at 80 °C for 48 h to obtain a solid superacid precursor; calcine the solid superacid precursor in air atmosphere at 600 °C for 6 h to obtain a solid superacid catalyst WO 3 / Ce 0.8 Fe 0.2 O 2 .

[0039] Reaction evaluation:

[0040] Put acrylic acid, catalyst, inhibitor and liquid isobutene into a reaction kettle, and carry out a stirring reaction at a temperature of 35 °C and an air pressure of 1.0 MPa for 4 h, with a stirring rate of 800 rpm to synthesize tert-butyl acrylate; among them, the mass ratio of acrylic acid, inhibitor and isobutene in the feed is 10:0.01:5.5, the mass of the catalyst is 10% of the mass of acrylic acid, and the inhibitor is a mixture of tert-butanol, phenothiazine, p-hydroxyanisole and tert-butylcatechol, with a mass ratio of 12:5:3:5.

[0041] Example 2

[0042] Catalyst preparation:

[0043] Weigh 10.42 g of Ce(NO 3 ) 3 ·6H 2 O, 5.16 g of ZrOCl2·8H 2 O, add 100 ml of deionized water and stir to dissolve to obtain solution A; weigh 1.30 g of ammonium metatungstate, add 50 ml of deionized water and stir to dissolve to obtain solution B; slowly add solution A dropwise to solution B with stirring, and obtain solution C after the addition; weigh 4.37 g of template CTAB, add 50 mL of deionized water and stir to dissolve, and slowly add the obtained solution to solution C. After the addition, continue to stir for 4 h; slowly add a precipitating agent which is a mixture of 0.1 mol / l (NH 4 ) 2 CO3 The precipitating agent mixed with ammonia water in equal volume was added until the pH reached 13, and stirring was continued for 4 h; the solution was transferred to a hydrothermal reactor with a liner and crystallized at 120 °C for 72 h; after crystallization, it was centrifuged and washed several times until there was no chloride ion, and then washed 3 times with a small amount of absolute ethanol; it was dried in vacuo at 80 °C for 48 h to obtain a solid superacid precursor; the solid superacid precursor was calcined in air atmosphere at 600 °C for 6 h to obtain a solid superacid catalyst WO 3 / Ce 0.6 Zr 0.4 O 2 。

[0044] Reaction evaluation:

[0045] Acrylic acid, catalyst, inhibitor and liquid isobutene were put into a reaction kettle, and under the conditions of a temperature of 35 °C and an air pressure of 1.0 MPa, stirring reaction was carried out for 4 h at a stirring rate of 800 rpm to synthesize tert-butyl acrylate; among them, the feeding mass ratio of acrylic acid, inhibitor and isobutene was 10:0.01:5.5, the mass of the catalyst was 10% of the mass of acrylic acid, and the inhibitor was a mixture of tert-butanol, phenothiazine, p-methoxyphenol and tert-butylcatechol, with a mass ratio of 12:5:3:5.

[0046] Example 3

[0047] Catalyst preparation:

[0048] Weigh 12.16 g of Ce(NO 3 ) 3 ·6H 2 O, 6.46 g of Fe(NO 3 ) 3 ·6H 2 O, 1.29 g of ZrOCl 2 ·8H 2 O and add them to 100 ml of deionized water and stir to dissolve to obtain solution A; weigh 4.37 g of ammonium metatungstate and add it to 50 ml of deionized water and stir to dissolve to obtain solution B; slowly add solution A dropwise to solution B under stirring, and after the addition is completed, solution C is obtained; weigh 4.37 g of template CTAB, add it to 50 mL of deionized water and stir to dissolve, and slowly add the obtained solution dropwise to solution C, and continue to stir for 4 h after the addition is completed; slowly add 0.1 mol / l (NH 4 ) 2 CO 3The precipitant mixed with ammonia water in equal volume was added until the pH reached 13, and stirring was continued for 4 h; the solution was transferred to a hydrothermal reactor with a liner and crystallized at 120 °C for 72 h; after crystallization, it was centrifuged and washed several times until there was no chloride ion, and then washed 3 times with a small amount of absolute ethanol; it was dried in vacuo at 80 °C for 48 h to obtain a solid superacid precursor; the solid superacid precursor was calcined in air atmosphere at 600 °C for 6 h to obtain a solid superacid catalyst WO 3 / Ce 0.7 Fe 0.2 Zr 0.1 O 2 。

[0049] Reaction evaluation:

[0050] Acrylic acid, catalyst, inhibitor and liquid isobutene were put into a reaction kettle, and under the conditions of a temperature of 35 °C and an air pressure of 1.0 MPa, stirring reaction was carried out for 4 h, and the stirring rate was 800 rpm to synthesize tert-butyl acrylate; among them, the feeding mass ratio of acrylic acid, inhibitor and isobutene was 10:0.01:5.5, the mass of the catalyst was 10% of the mass of acrylic acid, and the inhibitor was a mixture of tert-butanol, phenothiazine, p-hydroxyanisole and tert-butylcatechol, and the mass ratio was 12:5:3:5.

[0051] Example 4

[0052] Catalyst preparation:

[0053] Weigh 12.16 g of Ce(NO 3 ) 3 ·6H 2 O, 6.46 g of Fe(NO 3 ) 3 ·6H 2 O, 3.51 g of Nd(NO 3 ) 3 ·6H 2 O and add them to 100 ml of deionized water and stir to dissolve to obtain solution A; weigh 1.59 g of ammonium metatungstate and add it to 50 ml of deionized water and stir to dissolve to obtain solution B; slowly drop solution A into solution B under stirring, and after dropping, obtain solution C; weigh 4.37 g of template CTAB, add it to 50 mL of deionized water and stir to dissolve, and slowly drop the obtained solution into solution C, and continue to stir for 4 h after dropping; slowly drop 0.1 mol / l (NH 4 ) 2 CO 3The precipitant mixed with ammonia water in equal volume was added until the pH reached 13, and stirring was continued for 4 h; the solution was transferred to a hydrothermal autoclave with a liner and crystallized at 120 °C for 72 h; after crystallization, it was centrifuged and washed repeatedly until there was no chloride ion, and then washed 3 times with a small amount of absolute ethanol; it was dried in vacuo at 80 °C for 48 h to obtain a solid superacid precursor; the solid superacid precursor was calcined in air atmosphere at 600 °C for 6 h to obtain a solid superacid catalyst WO 3 / Ce 0.7 Fe 0.2 Nd 0.1 O 2 。

[0054] Reaction evaluation:

[0055] Acrylic acid, catalyst, inhibitor and liquid isobutene were put into a reaction kettle, and under the conditions of a temperature of 35 °C and an air pressure of 1.0 MPa, stirring reaction was carried out for 4 h, and the stirring rate was 800 rpm to synthesize tert-butyl acrylate; among them, the mass ratio of acrylic acid, inhibitor and isobutene in the feed was 10:0.01:5.5, the mass of the catalyst was 10% of the mass of acrylic acid, and the inhibitor was a mixture of tert-butanol, phenothiazine, p-hydroxyanisole and tert-butylcatechol, and the mass ratio was 12:5:3:5.

[0056] Example 5

[0057] Catalyst preparation:

[0058] Weigh 12.16 g of Ce(NO 3 ) 3 ·6H 2 O, 6.46 g of Fe(NO 3 ) 3 ·6H 2 O, 3.56 g of Sm(NO 3 ) 3 ·6H 2 O and add them to 100 ml of deionized water and stir to dissolve to obtain solution A; weigh 1.60 g of ammonium metatungstate and add it to 50 ml of deionized water and stir to dissolve to obtain solution B; slowly add solution A dropwise to solution B under stirring, and after the addition is completed, solution C is obtained; weigh 4.37 g of template CTAB, add it to 50 mL of deionized water and stir to dissolve, and slowly add the obtained solution dropwise to solution C, and continue stirring for 4 h after the addition is completed; slowly add 0.1 mol / l (NH 4 ) 2 CO 3The precipitating agent mixed with ammonia water in equal volume is added until the pH reaches 13, and stirring is continued for 4 h; the solution is transferred to a hydrothermal autoclave with a lining and crystallized for 72 h in an environment at 120 °C; after crystallization, it is centrifuged and washed repeatedly until there is no chloride ion, and then washed 3 times with a small amount of absolute ethanol; it is dried in vacuo at 80 °C for 48 h to obtain a solid superacid precursor; the solid superacid precursor is calcined in an air atmosphere at 600 °C for 6 h to obtain a solid superacid catalyst WO 3 / Ce 0.7 Fe 0.2 Sm 0.1 O 2 。

[0059] Reaction evaluation:

[0060] Acrylic acid, the catalyst, the inhibitor and liquid isobutene are put into a reaction kettle, and under the conditions of a temperature of 35 °C and an air pressure of 1.0 MPa, stirring reaction is carried out for 4 h at a stirring rate of 800 rpm to synthesize tert-butyl acrylate; among them, the feeding mass ratio of acrylic acid, the inhibitor and isobutene is 10:0.01:5.5, the mass of the catalyst is 10% of the mass of acrylic acid, and the inhibitor is a mixture of tert-butanol, phenothiazine, p-hydroxyanisole and tert-butylcatechol, and the mass ratio is 12:5:3:5.

[0061] Example 6

[0062] Catalyst preparation:

[0063] Weigh 12.16 g of Ce(NO 3 ) 3 ·6H 2 O, 6.46 g of Fe(NO 3 ) 3 ·6H 2 O, 1.05 g of SnCl 4 Add 100 ml of deionized water and stir to dissolve to obtain solution A; weigh 1.43 g of ammonium metatungstate and add 50 ml of deionized water and stir to dissolve to obtain solution B; slowly drip solution A into solution B under stirring, and after the dripping is completed, obtain solution C; weigh 4.37 g of template agent CTAB, add 50 mL of deionized water and stir to dissolve, and slowly drip the obtained solution into solution C, and continue stirring for 4 h after the dripping is completed; slowly drip 0.1 mol / l (NH 4 ) 2 CO 3The precipitant mixed with ammonia water in equal volume was added until the pH reached 13, and stirring was continued for 4 h; the solution was transferred to a hydrothermal autoclave with a liner and crystallized at 120 °C for 72 h; after crystallization, it was centrifuged and washed repeatedly until there was no chloride ion, and then washed 3 times with a small amount of absolute ethanol; it was dried in vacuum at 80 °C for 48 h to obtain a solid superacid precursor; the solid superacid precursor was calcined in air atmosphere at 600 °C for 6 h to obtain a solid superacid catalyst WO 3 / Ce 0.7 Fe 0.2 Sn 0.1 O 2 。

[0064] Reaction evaluation:

[0065] Acrylic acid, catalyst, inhibitor and liquid isobutene were put into a reaction kettle, and under the conditions of a temperature of 35 °C and an air pressure of 1.0 MPa, stirring reaction was carried out for 4 h with a stirring rate of 800 rpm to synthesize tert-butyl acrylate; among them, the feeding mass ratio of acrylic acid, inhibitor and isobutene was 10:0.01:5.5, the mass of the catalyst was 10% of the mass of acrylic acid, and the inhibitor was a mixture of tert-butanol, phenothiazine, p-hydroxyanisole and tert-butylcatechol with a mass ratio of 12:5:3:5.

[0066] Example 7

[0067] Catalyst preparation:

[0068] Weigh 3.51 g of Nd(NO 3 ) 3 ·6H 2 O and 2.1 g of SnCl 4 , add them to 100 ml of deionized water and stir to dissolve to obtain solution A; weigh 0.83 g of ammonium metatungstate and add it to 50 ml of deionized water and stir to dissolve to obtain solution B; slowly drop solution A into solution B with stirring, and after dropping, obtain solution C; weigh 1.75 g of template CTAB, add it to 50 mL of deionized water and stir to dissolve, and slowly drop the obtained solution into solution C, and continue stirring for 4 h after dropping; slowly drop 0.1 mol / l (NH 4 ) 2 CO 3 The precipitant mixed with ammonia water in equal volume was added until the pH reached 13, and stirring was continued for 4 h; the solution was transferred to a hydrothermal autoclave with a liner and crystallized at 120 °C for 72 h; after crystallization, it was centrifuged and washed repeatedly until there was no chloride ion, and then washed 3 times with a small amount of absolute ethanol; it was dried in vacuum at 80 °C for 48 h to obtain a solid superacid precursor; the solid superacid precursor was calcined in air atmosphere at 600 °C for 6 h to obtain a solid superacid catalyst WO 3 / Nd 0.5 Sn0.5 O 2 。

[0069] Reaction evaluation:

[0070] Acrylic acid, catalyst, inhibitor and liquid isobutene were put into a reaction kettle, and stirred and reacted for 4 h at a temperature of 35 °C and an air pressure of 1.0 MPa with a stirring rate of 800 rpm to synthesize tert-butyl acrylate; among them, the feeding mass ratio of acrylic acid, inhibitor and isobutene was 10:0.01:5.5, the mass of the catalyst was 10% of the mass of acrylic acid, and the inhibitor was a mixture of tert-butanol, phenothiazine, p-hydroxyanisole and tert-butylcatechol with a mass ratio of 12:5:3:5.

[0071] Example 8

[0072] Catalyst preparation:

[0073] Weigh 10.42 g of Ce(NO 3 ) 3 ·6H 2 O, 6.46 g of Fe(NO 3 ) 3 ·6H 2 O, 3.51 g of Nd(NO 3 ) 3 ·6H 2 O, 1.05 g of SnCl 4 Add and stir to dissolve in 100 ml of deionized water to obtain solution A; weigh 1.57 g of ammonium metatungstate and add and stir to dissolve in 50 ml of deionized water to obtain solution B; slowly drop solution A into solution B with stirring, and after the dropping is completed, obtain solution C; weigh 4.37 g of template agent CTAB, add and stir to dissolve in 50 mL of deionized water, and slowly drop the obtained solution into solution C. After the dropping is completed, continue to stir for 4 h; slowly drop 0.1 mol / l (NH 4 ) 2 CO 3 The precipitating agent mixed with ammonia water in equal volume until the pH is 13, and continue to stir for 4 h; transfer the solution to a hydrothermal kettle with a lining, and crystallize for 72 h in an environment of 120 °C; after crystallization, centrifuge and wash multiple times until there is no chloride ion, and then wash 3 times with a small amount of absolute ethanol; vacuum dry at 80 °C for 48 h to obtain a solid superacid precursor; calcine the solid superacid precursor in an air atmosphere at 600 °C for 6 h to obtain a solid superacid catalyst WO 3 / Ce 0.6 Fe 0.2 Nd 0.1 Sn 0.1 O 2 。

[0074] Reaction evaluation:

[0075] Acrylic acid, a catalyst, an inhibitor, and liquid isobutene are put into a reaction kettle, and under the conditions of a temperature of 35 °C and an air pressure of 1.0 MPa, they are stirred and reacted for 4 h at a stirring rate of 800 rpm to synthesize tert-butyl acrylate; among them, the feeding mass ratio of acrylic acid, inhibitor, and isobutene is 10:0.01:5.5, the mass of the catalyst is 10% of the mass of acrylic acid, and the inhibitor is a mixture of tert-butanol, phenothiazine, p-hydroxyanisole, and tert-butylcatechol, with a mass ratio of 12:5:3:5.

[0076] Comparative Example 1

[0077] Weigh 13.05 g of Ce(NO 3 ) 3 ·6H 2 O, 6.08 g of Fe(NO 3 ) 3 ·6H 2 O and add them to 100 ml of deionized water and stir to dissolve to obtain solution A; weigh 4.37 g of the template agent CTAB, add it to 50 mL of deionized water and stir to dissolve, and slowly add the obtained solution dropwise to solution A. After the addition is complete, continue to stir for 4 h; slowly add dropwise a precipitating agent prepared by mixing 0.1 mol / l (NH 4 ) 2 CO 3 and ammonia water in equal volume until the pH reaches 13, and continue to stir for 4 h; transfer the solution to a hydrothermal kettle with a lining, and crystallize at 120 °C for 72 h in an environment; after crystallization, centrifuge and wash multiple times until there is no chloride ion, and then wash 3 times with a small amount of absolute ethanol; vacuum dry at 80 °C for 48 h to obtain a solid superacid precursor; calcine the solid superacid precursor in an air atmosphere at 600 °C for 6 h to obtain a solid superacid catalyst Ce 0.8 Fe 0.2 O 2 .

[0078] Reaction evaluation:

[0079] Acrylic acid, a catalyst, an inhibitor, and liquid isobutene are put into a reaction kettle, and under the conditions of a temperature of 35 °C and an air pressure of 1.0 MPa, they are stirred and reacted for 4 h at a stirring rate of 800 rpm to synthesize tert-butyl acrylate; among them, the feeding mass ratio of acrylic acid, inhibitor, and isobutene is 10:0.01:5.5, the mass of the catalyst is 10% of the mass of acrylic acid, and the inhibitor is a mixture of tert-butanol, phenothiazine, p-hydroxyanisole, and tert-butylcatechol, with a mass ratio of 12:5:3:5.

[0080] Comparative Example 2

[0081] Catalyst preparation:

[0082] Weigh 10.42 g of Ce(NO 3 ) 3 ·6H 2 O, 5.16 g of ZrOCl 2 ·8H 2 O and add them to 100 ml of deionized water, stir to dissolve, and obtain solution A; weigh 4.37 g of template CTAB, add it to 50 mL of deionized water, stir to dissolve, and slowly add the obtained solution dropwise to solution A. After the addition is complete, continue stirring for 4 h; slowly add dropwise a precipitant prepared by mixing 0.1 mol / l (NH 4 ) 2 CO 3 and ammonia water in equal volume until the pH reaches 13, and continue stirring for 4 h; transfer the solution to a hydrothermal autoclave with a liner, and crystallize at 120 °C for 72 h; after crystallization, centrifuge and wash repeatedly until there is no chloride ion, and then wash 3 times with a small amount of absolute ethanol; dry under vacuum at 80 °C for 48 h to obtain a solid superacid precursor; calcine the solid superacid precursor in an air atmosphere at 600 °C for 6 h to obtain a solid superacid catalyst Ce 0.6 Zr 0.4 O 2 。

[0083] Reaction evaluation:

[0084] Put acrylic acid, catalyst, inhibitor and liquid isobutene into a reaction kettle, and under the conditions of a temperature of 35 °C and an air pressure of 1.0 MPa, stir and react for 4 h at a stirring rate of 800 rpm to synthesize tert-butyl acrylate; among them, the mass ratio of the feed of acrylic acid, inhibitor and isobutene is 10:0.01:5.5, the mass of the catalyst is 10% of the mass of acrylic acid, and the inhibitor is a mixture of tert-butanol, phenothiazine, p-hydroxyanisole and tert-butylcatechol, with a mass ratio of 12:5:3:5.

[0085] Comparative example 3

[0086] Catalyst preparation:

[0087] Weigh 3.51 g of Nd(NO 3 ) 3 ·6H 2 O, 2.1 g of SnCl 4 and add them to 100 ml of deionized water, stir to dissolve, and obtain solution A; weigh 1.75 g of template CTAB, add it to 50 mL of deionized water, stir to dissolve, and slowly add the obtained solution dropwise to solution A. After the addition is complete, continue stirring for 4 h; slowly add dropwise a precipitant prepared by mixing 0.1 mol / l (NH 4 ) 2 CO 3The precipitant mixed with ammonia water in equal volume was added until the pH reached 13, and stirring was continued for 4 h; the solution was transferred to a hydrothermal autoclave with a liner and crystallized at 120 °C for 72 h; after crystallization, it was centrifuged and washed several times until there was no chloride ion, and then washed 3 times with a small amount of absolute ethanol; it was dried in vacuo at 80 °C for 48 h to obtain a solid superacid precursor; the solid superacid precursor was calcined in an air atmosphere at 600 °C for 6 h to obtain a solid superacid catalyst Nd 0.5 Sn 0.5 O 2 。

[0088] Reaction evaluation:

[0089] Acrylic acid, catalyst, inhibitor and liquid isobutene were put into a reaction kettle, and under the conditions of a temperature of 35 °C and an air pressure of 1.0 MPa, stirring reaction was carried out for 4 h, and the stirring rate was 800 rpm to synthesize tert-butyl acrylate; among them, the feeding mass ratio of acrylic acid, inhibitor and isobutene was 10:0.01:5.5, the mass of the catalyst was 10% of the mass of acrylic acid, the inhibitor was a mixture of tert-butanol, phenothiazine, p-hydroxyanisole and tert-butylcatechol, and the mass ratio was 12:5:3:5.

[0090] Comparative Example 4

[0091] Using p-toluenesulfonic acid as the catalyst, acrylic acid, catalyst, inhibitor and liquid isobutene were put into a reaction kettle, and under the conditions of a temperature of 35 °C and an air pressure of 1.0 MPa, stirring reaction was carried out for 4 h, and the stirring rate was 800 rpm to synthesize tert-butyl acrylate; among them, the feeding molar ratio of acrylic acid, inhibitor and isobutene was 10:0.01:5.5, the mass of the catalyst was 10% of the mass of acrylic acid, the inhibitor was a mixture of tert-butanol, phenothiazine, p-hydroxyanisole and tert-butylcatechol, and the mass ratio was 12:5:3:5.

[0092] Comparative Example 5

[0093] Using acidic cation resin as the catalyst, acrylic acid, catalyst, inhibitor and liquid isobutene were put into a reaction kettle, and under the conditions of a temperature of 35 °C and an air pressure of 1.0 MPa, stirring reaction was carried out for 4 h, and the stirring rate was 800 rpm to synthesize tert-butyl acrylate; among them, the feeding mass ratio of acrylic acid, inhibitor and isobutene was 10:0.01:5.5, the mass of the catalyst was 10% of the mass of acrylic acid, the inhibitor was a mixture of tert-butanol, phenothiazine, p-hydroxyanisole and tert-butylcatechol, and the mass ratio was 12:5:3:5.

[0094] The tert-butyl acrylate prepared in the examples and comparative examples was tested, and the test standard adopted the conventional experiments and regulations in the field to determine the esterification rate. The specific results are shown in Table 1, where:

[0095] When the olefin is in excess, the esterification rate is calculated according to Equation (1):

[0096] Esterification rate = (1 - acid value of the reaction system after reaction / acid value of the reaction system before reaction) * 100% (1);

[0097] When the acid is in excess, the esterification rate is converted according to the molar ratio of olefin to acid and calculated as in Equation (2):

[0098] Esterification rate = [(esterification rate in Equation (1) / molar ratio of olefin to acid)] * 100% (2).

[0099] The product selectivity is calculated based on the peak area ratio of chromatographic analysis, and the results are shown in Table 1.

[0100] Table 1. Esterification rate and tert-butyl acrylate selectivity of Examples 1-8 and Comparative Examples 1-5

[0101] Embodiment Catalyst Esterification rate % Selectivity of tert-butyl acrylate % Example 1 <![CDATA[WO 3 / Ce 0.8 Fe 0.2 O 2 > 85.8 92.4 Example 2 <![CDATA[WO 3 / Ce 0.6 Zr 0.4 O 2 > 73.6 94.6 Example 3 <![CDATA[WO 3 / Ce 0.7 Fe 0.2 Zr 0.1 O 2 > 85.0 97.7 Example 4 <![CDATA[WO 3 / Ce 0.7 Fe 0.2 Nd 0.1 O 2 > 93.3 96.3 Example 5 <![CDATA[WO 3 / Ce 0.7 Fe 0.2 Sm 0.1 O 2 > 92.6 95.2 Example 6 <![CDATA[WO 3 / Ce 0.7 Fe 0.2 Sn 0.1 O 2 > 92.1 93.5 Example 7 <![CDATA[WO 3 / Nd 0.5 Sn 0.5 O 2 > 88.3 95.4 Example 8 <![CDATA[WO 3 / Ce 0.6 Fe 0.2 Nd 0.1 Sn 0.1 O 2 > 98.5 97.9 Comparative Example 1 <![CDATA[Ce 0.8 Fe 0.2 O 2 > 37.1 95.3 Comparative Example 2 <![CDATA[Ce 0.6 Zr 0.4 O 2 > 25.3 96.2 Comparative Example 3 <![CDATA[Nd 0.5 Sn 0.5 O 2 > 52.6 95.7 Comparative Example 4 p-Toluenesulfonic acid 82.6 94.8 Comparative Example 5 Acidic cation resin 90.5 95.4

[0102] From the results in Table 1, it can be seen that compared with the comparative examples, the preparation method of the present invention significantly improves the esterification rate of the esterification reaction, while reducing the reaction temperature, making the reaction milder, more green and economical, and effectively preventing the polymerization of raw materials and products during the reaction, and improving the selectivity of the product.

[0103] The above-mentioned embodiments are only preferred embodiments given to fully illustrate the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A method for synthesizing tert-butyl (meth)acrylate using WO 3 / Ce x Fe y M z O 2 catalyst It is characterized in that Mix WO 3 / Ce x Fe y M z O 2 catalyst, inhibitor, (meth)acrylic acid and isobutene in a reaction kettle to synthesize tert-butyl (meth)acrylate. WO 3 / Ce x Fe y M z O 2 In the catalyst, M is one or more of Zr, Sn, Nd, and Sm; Based on the total mass of CeO 2 and Fe 2 O 3 The content of WO 3 is 0.1 - 30%, 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1; the inhibitor is used in combination with air, wherein the inhibitor is a combination of tert-butanol, phenothiazine, p-methoxyphenol, and tert-butylcatechol, and the mass ratio is 10-15:4-6:2-4:4-6; the preparation method of the catalyst includes the following steps: 1) Weigh soluble salts of Ce, Fe, and M, add deionized water and stir to dissolve to obtain solution A; 2) Weigh soluble salts of W, add deionized water and stir to dissolve to obtain solution B; 3) Slowly drop solution A into solution B under stirring, and after the dropping is completed, obtain solution C; 4) Weigh a certain amount of template CTAB, add deionized water and stir to dissolve, slowly drop the obtained solution into solution C, and continue to stir for 2-6 h after the dropping is completed; 5) Slowly drop a precipitating agent into the solution obtained in step 4) under stirring until the pH is 9-14, and continue to stir for 2-10 h; 6) Transfer the solution obtained in step 5) to a hydrothermal autoclave and crystallize at 70-180 °C for 6-96 h; 7) After crystallization, centrifuge and wash until there is no chloride ion, then wash with absolute ethanol 1-5 times, and dry in vacuum to obtain a precursor; 8) The precursor is calcined in an air atmosphere at 400 - 1100 °C for 2 - 12 h to obtain the composite oxide WO 3 / Ce x Fe y M z O 2 。 2. According to the method described in claim 1, it is characterized in that the reaction temperature is 30-60 °C, the air pressure is 0.1-5.0 MPa, the reaction time is 2-10 h, and the stirring rate is 500-1500 rpm.

3. According to the method described in claim 1, it is characterized in that (meth)acrylic acid and isobutene have a molar ratio of 0.2:1-5:1; the inhibitor is 0.01-1% of the mass of (meth)acrylic acid; the mass of the catalyst is 5-20% of the mass of (meth)acrylic acid.

4. According to the method described in claim 1, it is characterized in that the (meth)acrylic acid includes acrylic acid and methacrylic acid; the tert-butyl (meth)acrylate includes tert-butyl acrylate and tert-butyl methacrylate.

5. According to the method described in claim 1, it is characterized in that The ratio of the total molar amount of the template agent to the metal ions described in step 4) is 1:1 - 1:20; the precipitating agent described in step 5) is NH 4 HCO 3 (NH 4 ) 2 CO 3 Na 2 CO 3 , NaOH, ammonia water or urea, or one or more of them.

6. According to the method described in claim 1, it is characterized in that in step 6), the crystallization temperature is 100-150 °C and the crystallization time is 48-96 h.

7. According to the method described in claim 1, it is characterized in that in step 8), the calcination temperature is 500-700 °C and the calcination time is 4-10 h.