A supported resin catalyst and its preparation method and application

Abstract

The invention discloses a supported resin catalyst and a preparation method and application thereof, and relates to the technical field of resin catalysts. The invention prepares a novel supported resin catalyst, and applies the supported resin catalyst to the synthesis of methyl methacrylate by reacting methacrolein with methanol. By adopting a single active component, palladium, the conversion rate of methacrolein can be increased to over 97%, and the selectivity of methyl methacrylate can be increased to over 98%. The amount of the active component, palladium, used is about 1.5% of the mass of the methacrolein.

Description

Technical field:

[0001] The present invention relates to the technical field of resin catalysts, and in particular to a supported resin catalyst and a preparation method and application thereof. Background technology:

[0002] Methyl methacrylate is an important monomer for the preparation of polymethyl methacrylate (PMMA, plexiglass). Polymethyl methacrylate is widely used in daily necessities, instruments and meters, construction, transportation, advertising and decoration, national defense and military industry, coatings, latex paints and other fields.

[0003] At present, the synthesis of methyl methacrylate mainly adopts the methacrolein-methanol oxidative esterification method. Compared with the traditional methacrylic acid-methanol oxidative esterification method, the process is simpler, more environmentally friendly, does not use highly corrosive methacrylic acid, and has low requirements for reaction equipment. However, it has very high requirements for the catalytic performance of the catalyst. At the same time, the cost of the catalyst must also be considered, otherwise it will be unfavorable for the large-scale production of methyl methacrylate.

[0004] Patent CN200710057680.0 discloses a resin catalyst for preparing methyl methacrylate and its preparation method. The catalyst carrier is a styrene-divinylbenzene copolymer resin with a specific surface area of ​​300-800m 2 / g, with an average pore size of 2-30nm; the active components loaded on the carrier are in the following mass percentages relative to the carrier: palladium 2%-5%, bismuth 0-3%, lead 0.3%-1%, iron 0.3%-1%, and lanthanum 0-1%. Calculations show that the average conversion of methacrolein in Examples 1-8 was 94.7%, and the average selectivity to methyl methacrylate was 97.4%. Although the resin catalyst prepared in this patent can significantly improve the conversion of methacrolein and the selectivity to methyl methacrylate, the active components in the resin catalyst are relatively complex. Only when five active components are used can the conversion of methacrolein reach above 95%, while the selectivity to methyl methacrylate reaches above 98%. Using five active components not only increases the workload and cost of preparing the resin catalyst, but also increases the cost of preparing the resin catalyst. Summary of the invention:

[0005] The technical problem to be solved by the present invention is to provide a supported resin catalyst and a preparation method thereof. The prepared supported resin catalyst can be applied to the synthesis of methyl methacrylate by the reaction of methacrolein and methanol, thereby greatly improving the conversion rate of the raw material methacrolein and the selectivity of the product methyl methacrylate.

[0006] The technical problem to be solved by the present invention is achieved by adopting the following technical solutions:

[0007] One of the purposes of the present invention is to provide a supported resin catalyst, which uses resin microspheres as a carrier and palladium as an active component; the resin microspheres are prepared from N-vinylcarbamic acid benzyl ester, divinylbenzene, a porogen, a dispersant, an initiator and deionized water through a suspension polymerization method.

[0008] The mass fraction of the palladium in the supported resin catalyst is 1-20%, preferably 5-20%.

[0009] The particle size of the resin microspheres is 0.5-1.2 mm, and the specific surface area is greater than 580 m 2 / g, and the average pore size is 8-20nm.

[0010] A second object of the present invention is to provide a method for preparing the aforementioned supported resin catalyst, comprising: first, immersing resin microspheres in a methanol solution of palladium chloride, stirring, centrifuging, and washing with methanol; then adding the microspheres to a methanol solution of sodium borohydride, adjusting the pH to 8-10 with a sodium hydroxide solution, stirring, centrifuging, washing with methanol, and drying to obtain the supported resin catalyst.

[0011] A third object of the present invention is to provide the use of the aforementioned supported resin catalyst in the synthesis of methyl methacrylate by the reaction of methacrolein and methanol.

[0012] The present invention has the beneficial effects of preparing a novel supported resin catalyst, and applying the supported resin catalyst to the synthesis of methyl methacrylate by reacting methacrolein with methanol. By using a single active component, palladium, the conversion rate of methacrolein can be increased to over 97%, and the selectivity of methyl methacrylate can be increased to over 98%. The amount of the active component, palladium, used is approximately 1.5% of the mass of the methacrolein. Specific implementation method:

[0013] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific embodiments.

[0014] The invention provides a supported resin catalyst, which uses resin microspheres as a carrier and palladium as an active component; the resin microspheres are prepared from N-vinylcarbamic acid benzyl ester, divinylbenzene, a porogen, a dispersant, an initiator and deionized water through a suspension polymerization method.

[0015] The present invention uses N-vinyl benzyl carbamate as a polymerization monomer, which can significantly enhance the adsorption performance of the prepared resin microspheres compared to styrene, increase the palladium loading, and increase the contact area between the prepared supported resin catalyst and the reaction substrate, thereby accelerating the reaction rate and improving the raw material conversion rate and product selectivity.

[0016] Preferably, the mass fraction of palladium in the supported resin catalyst is 1-20%, preferably 5-20%.

[0017] Preferably, the particle size of the resin microspheres is 0.5-1.2 mm, and the specific surface area is greater than 580 m 2 / g, and the average pore size is 8-20nm.

[0018] Preferably, the amount of divinylbenzene used is 5-20% by mass based on the mass of N-vinylbenzylcarbamate.

[0019] Preferably, the porogen is at least one of toluene, xylene, 200# gasoline, n-hexane, n-heptane, liquid paraffin, and paraffin wax, and the amount of the porogen used is 0.5-2.5 times the mass of N-vinylcarbamic acid benzyl ester. Of course, other C7-C20 alkanes or alkanols not listed here can also be used as porogens.

[0020] Preferably, the dispersant is at least one of polyvinyl alcohol, gelatin, methyl cellulose, and sodium lignin sulfonate, and the amount of the dispersant is 0.5-2% of the mass of deionized water. Of course, sodium lauryl sulfate, hydroxyethyl cellulose, and other commonly used dispersants in the art can also be used.

[0021] Preferably, the mass ratio of the deionized water to N-vinyl benzyl carbamate is (1-3):1.

[0022] Preferably, the initiator is at least one of benzoyl peroxide, azobisisobutyronitrile, ammonium persulfate, and potassium persulfate, and the amount of the initiator used is 0.5-2% of the mass of N-vinylcarbamate. Of course, commonly used initiators in the art, such as tert-butyl benzoyl peroxide, methyl ethyl ketone peroxide, and azobisisoheptylnitrile, may also be used.

[0023] The present invention also provides a method for preparing the aforementioned supported resin catalyst, comprising: firstly immersing resin microspheres in a methanol solution of palladium chloride, stirring, centrifuging, and washing with methanol; then adding the microspheres into a methanol solution of sodium borohydride, stirring, centrifuging, washing with methanol, and drying to obtain the supported resin catalyst.

[0024] The present invention further provides the use of the aforementioned supported resin catalyst in the synthesis of methyl methacrylate by reacting methacrolein with methanol. Of course, the aforementioned supported resin catalyst can also be used in the synthesis of methyl acrylate by reacting acrolein with methanol, achieving higher conversion rates and yields. The aforementioned supported resin catalyst can also be used in the synthesis of specific compounds by the aldol reaction to form esters.

[0025] The technical solution of the present invention is described in detail below through specific embodiments:

[0026] Example 1

[0027] 1. Preparation of resin microspheres:

[0028] 50 g of N-vinyl benzyl carbamate, 2.5 g of divinylbenzene, 50 g of xylene and 0.5 g of benzoyl peroxide were mixed and stirred to obtain an oil phase; polyvinyl alcohol was added to deionized water, the mass ratio of deionized water to N-vinyl benzyl carbamate was 2:1, and the amount of polyvinyl alcohol was 1% of the mass of deionized water, and stirred to dissolve to obtain an aqueous phase; the oil phase was then added to the aqueous phase, the temperature was raised to 60° C. to react for 2 hours, and then the temperature was raised to 80° C. to react for 5 hours; after the reaction, the mixture was washed with water, filtered, dried, the porogen was extracted with acetone, washed with water, and dried to obtain resin microspheres.

[0029] 2. Preparation of supported resin catalyst:

[0030] First, 1g of resin microspheres was immersed in a methanol solution containing 1g of palladium chloride, stirred for 12 hours, centrifuged, and washed with methanol. The solution was then added to a methanol solution containing 0.1g of sodium borohydride, the pH adjusted to 9 with sodium hydroxide solution, stirred for 12 hours, centrifuged, washed with methanol, and dried to obtain a supported resin catalyst. The mass fraction of palladium was 6.9%.

[0031] 3. Synthesis of methyl methacrylate:

[0032] 100 g of methacrolein, 150 g of methanol, and 20 g of the supported resin catalyst prepared in this example were added to an autoclave. The reactor was sealed, stirred, and heated to 70°C for 5 hours. Oxygen was introduced at a rate of 10 mL / min during the reaction. The methacrolein conversion and methyl methacrylate selectivity were analyzed by gas chromatography. The methacrolein conversion was 97.2%, and the methyl methacrylate selectivity was 98.7%.

[0033] Example 2

[0034] 1. Preparation of resin microspheres:

[0035] 50 g of N-vinyl benzyl carbamate, 5 g of divinylbenzene, 50 g of n-heptane and 0.35 g of benzoyl peroxide were mixed and stirred to obtain an oil phase; polyvinyl alcohol was added to deionized water, the mass ratio of deionized water to N-vinyl benzyl carbamate was 3:1, and the amount of polyvinyl alcohol was 1.5% of the mass of deionized water, and stirred to dissolve to obtain an aqueous phase; the oil phase was then added to the aqueous phase, the temperature was raised to 60° C. to react for 2 h, and then the temperature was raised to 80° C. to react for 5 h; after the reaction, the mixture was washed with water, filtered, dried, the porogen was extracted with acetone, washed with water, and dried to obtain resin microspheres.

[0036] 2. Preparation of supported resin catalyst:

[0037] First, 1g of resin microspheres was immersed in a methanol solution containing 1g of palladium chloride, stirred for 12 hours, centrifuged, and washed with methanol. The solution was then added to a methanol solution containing 0.15g of sodium borohydride, the pH adjusted to 8 with sodium hydroxide solution, stirred for 12 hours, centrifuged, washed with methanol, and dried to obtain a supported resin catalyst. The mass fraction of palladium was 7.2%.

[0038] 3. Synthesis of methyl methacrylate:

[0039] 100 g of methacrolein, 150 g of methanol, and 20 g of the supported resin catalyst prepared in this example were added to an autoclave. The autoclave was sealed, stirred, and heated to 70°C for 5 hours. Oxygen was introduced at a rate of 10 mL / min during the reaction. The methacrolein conversion and methyl methacrylate selectivity were analyzed by gas chromatography. The methacrolein conversion was 97.5%, and the methyl methacrylate selectivity was 98.5%.

[0040] Example 3

[0041] 1. Preparation of resin microspheres:

[0042] 50 g of N-vinyl benzyl carbamate, 5 g of divinylbenzene, 100 g of xylene and 0.5 g of azobisisobutyronitrile were mixed and stirred to obtain an oil phase; polyvinyl alcohol was added to deionized water, the mass ratio of deionized water to N-vinyl benzyl carbamate was 1:1, and the amount of polyvinyl alcohol was 1% of the mass of deionized water, and stirred to dissolve to obtain an aqueous phase; the oil phase was then added to the aqueous phase, the temperature was raised to 60° C. to react for 2 h, and then the temperature was raised to 80° C. to react for 5 h; after the reaction, the mixture was washed with water, filtered, dried, the porogen was extracted with acetone, washed with water, and dried to obtain resin microspheres.

[0043] 2. Preparation of supported resin catalyst:

[0044] First, 1g of resin microspheres was immersed in a methanol solution containing 1.5g of palladium chloride, stirred for 12 hours, centrifuged, and washed with methanol. The solution was then added to a methanol solution containing 0.1g of sodium borohydride, the pH adjusted to 8 with sodium hydroxide solution, stirred for 12 hours, centrifuged, washed with methanol, and dried to obtain a supported resin catalyst. The mass fraction of palladium was 7.8%.

[0045] 3. Synthesis of methyl methacrylate:

[0046] 100 g of methacrolein, 150 g of methanol, and 20 g of the supported resin catalyst prepared in this example were added to an autoclave. The reactor was sealed, stirred, and heated to 70°C for 5 hours. Oxygen was introduced at a rate of 10 mL / min during the reaction. The methacrolein conversion and methyl methacrylate selectivity were analyzed by gas chromatography. The methacrolein conversion was 97.9%, and the methyl methacrylate selectivity was 99.0%.

[0047] Example 4

[0048] 1. Preparation of resin microspheres:

[0049] 50 g of N-vinyl benzyl carbamate, 8 g of divinylbenzene, 100 g of liquid paraffin and 0.5 g of azobisisobutyronitrile were mixed and stirred to obtain an oil phase; gelatin was added to deionized water, the mass ratio of deionized water to N-vinyl benzyl carbamate was 2:1, and the amount of gelatin was 1.5% of the mass of deionized water, and stirred to dissolve to obtain an aqueous phase; the oil phase was then added to the aqueous phase, the temperature was raised to 60° C. to react for 2 h, and then the temperature was raised to 80° C. to react for 5 h; after the reaction, the mixture was washed with water, filtered, dried, the porogen was extracted with acetone, washed with water, and dried to obtain resin microspheres.

[0050] 2. Preparation of supported resin catalyst:

[0051] First, 1g of resin microspheres was immersed in a methanol solution containing 1.5g of palladium chloride, stirred for 12 hours, centrifuged, and washed with methanol. The solution was then added to a methanol solution containing 0.2g of sodium borohydride, the pH adjusted to 10 with sodium hydroxide solution, stirred for 12 hours, centrifuged, washed with methanol, and dried to obtain a supported resin catalyst. The mass fraction of palladium was 8.0%.

[0052] 3. Synthesis of methyl methacrylate:

[0053] 100 g of methacrolein, 150 g of methanol, and 20 g of the supported resin catalyst prepared in this example were added to an autoclave. The autoclave was sealed, stirred, and heated to 70°C for 5 hours. Oxygen was introduced at a rate of 10 mL / min during the reaction. The methacrolein conversion and methyl methacrylate selectivity were analyzed by gas chromatography. The methacrolein conversion was 97.8%, and the methyl methacrylate selectivity was 98.7%.

[0054] Example 5

[0055] 1. Preparation of resin microspheres:

[0056] 50 g of N-vinyl benzyl carbamate, 10 g of divinylbenzene, 50 g of liquid paraffin and 0.8 g of potassium persulfate were mixed and stirred to obtain an oil phase; gelatin was added to deionized water, the ratio of deionized water to monomer N-vinyl benzyl carbamate was 1.5:1, and the amount of gelatin was 1.5% of the mass of deionized water, and stirred to dissolve to obtain an aqueous phase; the oil phase was then added to the aqueous phase, the temperature was raised to 60° C. to react for 2 h, and then the temperature was raised to 80° C. to react for 5 h; after the reaction, the mixture was washed with water, filtered, dried, the porogen was extracted with acetone, washed with water, and dried to obtain resin microspheres.

[0057] 2. Preparation of supported resin catalyst:

[0058] First, 1g of resin microspheres was immersed in a methanol solution containing 1g of palladium chloride, stirred for 12 hours, centrifuged, and washed with methanol. The solution was then added to a methanol solution containing 0.2g of sodium borohydride, the pH adjusted to 10 with sodium hydroxide solution, stirred for 12 hours, centrifuged, washed with methanol, and dried to obtain a supported resin catalyst. The mass fraction of palladium was 8.2%.

[0059] 3. Synthesis of methyl methacrylate:

[0060] 100 g of methacrolein, 150 g of methanol, and 20 g of the supported resin catalyst prepared in this example were added to an autoclave. The reactor was sealed, stirred, and heated to 70°C for 5 hours. Oxygen was introduced at a rate of 10 mL / min during the reaction. The methacrolein conversion and methyl methacrylate selectivity were analyzed by gas chromatography. The methacrolein conversion was 98.2%, and the methyl methacrylate selectivity was 99.0%.

[0061] Example 6

[0062] 1. Preparation of resin microspheres:

[0063] 50g of N-vinylcarbamic acid benzyl ester, 10g of divinylbenzene, 100g of n-heptane and 1g of ammonium persulfate were mixed and stirred to obtain an oil phase; methyl cellulose was added to deionized water in a mass ratio of deionized water to N-vinylcarbamic acid benzyl ester of 2:1, and the amount of methyl cellulose was 1% of the mass of deionized water, and stirred to dissolve to obtain an aqueous phase; the oil phase was then added to the aqueous phase, the temperature was raised to 60°C for reaction for 2h, and then the temperature was raised to 80°C for reaction for 5h; after the reaction, the mixture was washed with water, filtered, dried, the porogen was extracted with acetone, washed with water, and dried to obtain resin microspheres.

[0064] 2. Preparation of supported resin catalyst:

[0065] First, 1g of resin microspheres was immersed in a methanol solution containing 2g of palladium chloride, stirred for 12 hours, centrifuged, and washed with methanol. The solution was then added to a methanol solution containing 0.2g of sodium borohydride, the pH adjusted to 10 with sodium hydroxide solution, stirred for 12 hours, centrifuged, washed with methanol, and dried to obtain a supported resin catalyst. The mass fraction of palladium was 8.5%.

[0066] 3. Synthesis of methyl methacrylate:

[0067] 100 g of methacrolein, 150 g of methanol, and 20 g of the supported resin catalyst prepared in this example were added to an autoclave. The reactor was sealed, stirred, and heated to 70°C for 5 hours. Oxygen was introduced at a rate of 10 mL / min during the reaction. The methacrolein conversion and methyl methacrylate selectivity were analyzed by gas chromatography. The methacrolein conversion was 97.9%, and the methyl methacrylate selectivity was 98.8%.

[0068] Comparative Example 1

[0069] In Comparative Example 1, the monomer N-vinylbenzylcarbamate used in preparing the resin microspheres in Example 1 was replaced with styrene of the same mass, and the remaining preparation steps were the same as in Example 1.

[0070] The mass fraction of palladium is 4.2%.

[0071] The conversion of methacrolein was 92.8%, and the selectivity of methyl methacrylate was 94.7%.

[0072] Comparative Example 2

[0073] Comparative Example 2 is to replace the monomer N-vinylcarbamate benzyl ester used in preparing the resin microspheres in Example 1 with benzyl but-3-enoate of the same mass, and the remaining preparation steps are the same as in Example 1.

[0074] The mass fraction of palladium is 3.5%.

[0075] The conversion of methacrolein was 91.4%, and the selectivity of methyl methacrylate was 93.6%.

[0076] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A supported resin catalyst for use in the synthesis of methyl methacrylate by the reaction of methacrolein and methanol, wherein the supported resin catalyst comprises resin microspheres as a carrier and palladium as an active component; the resin microspheres are prepared by suspension polymerization from benzyl N-vinylcarbamate, divinylbenzene, a porogen, a dispersant, an initiator, and deionized water; the resin microspheres have a particle size of 0.5-1.2 mm and a specific surface area greater than 580 m 2 / g, average pore size is 8-20nm; The amount of divinylbenzene used is 5-20% by mass of N-vinylbenzylcarbamate.

2. The use according to claim 1, characterized in that: The mass fraction of the palladium in the supported resin catalyst is 1-20%.

3. The use according to claim 2, characterized in that: The mass fraction of the palladium in the supported resin catalyst is 5-20%.

4. The use according to claim 1, characterized in that: The porogen is at least one of toluene, xylene, 200# gasoline, n-hexane, n-heptane, liquid paraffin, and solid paraffin. The amount of the porogen is 0.5-2.5 times the mass of N-vinyl benzyl carbamate.

5. The use according to claim 1, characterized in that: The dispersant is at least one of polyvinyl alcohol, gelatin, methyl cellulose, and sodium lignin sulfonate, and the amount of the dispersant is 0.5-2% of the mass of deionized water.

6. The use according to claim 1, characterized in that: The mass ratio of the deionized water to N-vinyl benzyl carbamate is (1-3):

1.

7. The use according to claim 1, characterized in that: The initiator is at least one of benzoyl peroxide, azobisisobutyronitrile, ammonium persulfate, and potassium persulfate, and the amount of the initiator is 0.5-2% of the mass of N-vinyl benzyl carbamate.

8. The use according to any one of claims 1 to 7, characterized in that The preparation method of the supported resin catalyst comprises the following steps: firstly immersing resin microspheres in a methanol solution of palladium chloride, stirring, centrifuging, and washing with methanol; then adding the microspheres into a methanol solution of sodium borohydride, adjusting the pH to 8-10 with a sodium hydroxide solution, stirring, centrifuging, washing with methanol, and drying to obtain the supported resin catalyst.