Catalyst for synthesizing diphenyl carbonate through ester exchange as well as preparation method and application of catalyst

Abstract

The invention discloses a catalyst for synthesizing diphenyl carbonate through transesterification as well as a preparation method and application of the catalyst, and the preparation method comprises the following steps: uniformly mixing tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and a ZSM molecular sieve to obtain a mixture; adding water into the mixture, granulating and drying to obtain particles; and roasting the particulate matters to obtain the diphenyl carbonate catalyst for ester exchange reaction synthesis. According to the catalyst prepared through a specific technology, the prepared catalyst has high catalytic efficiency through limitation of all raw materials and technological parameters, the conversion efficiency of dimethyl carbonate and the selectivity of diphenyl carbonate can be remarkably improved, meanwhile, the preparation method is simple in technology, production is easy, and the catalyst is suitable for industrial production. And the prepared catalyst has good stability and can be recycled.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, and in particular to a catalyst for synthesizing diphenyl carbonate by ester exchange, a preparation method and an application thereof. Background Art

[0002] Diphenyl carbonate (DPC) is a white crystalline solid that is insoluble in water but soluble in organic solvents such as hot ethanol, benzene, ether, carbon tetrachloride, glacial acetic acid, etc. It can be decomposed by hot alkali. It is mainly used as a synthetic raw material for engineering plastics such as polycarbonate and polyparaben, and can also be used as a plasticizer and solvent for nitrocellulose.

[0003] Diphenyl carbonate is an important new type of engineering plastic intermediate. It is pollution-free and low-toxic. It is mainly used in the plastics industry and is often used to synthesize polycarbonate. The main methods for synthesizing diphenyl carbonate are phosgene method, transesterification method and phenol oxidative carbonylation method.

[0004] At present, the preparation method of diphenyl carbonate is generally to synthesize diphenyl carbonate by reacting phenol with dimethyl carbonate in the presence of a catalyst. However, this method has the problems of low dimethyl carbonate conversion rate and diphenyl carbonate selectivity.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a catalyst for synthesizing diphenyl carbonate by ester exchange, a preparation method and an application thereof. The catalyst has high catalytic efficiency, can significantly improve the conversion efficiency of dimethyl carbonate and the selectivity of diphenyl carbonate, and at the same time, the catalyst can be repeatedly recycled.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0008] The first aspect of the present invention provides a method for preparing a catalyst for synthesizing diphenyl carbonate by transesterification, the method comprising the following steps:

[0009] (a) mixing tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve to obtain a mixture;

[0010] (b) adding water to the mixture, granulating, and drying to obtain granules;

[0011] (c) calcining the particles to obtain the catalyst for synthesizing diphenyl carbonate by ester exchange reaction.

[0012] Preferably, the mass ratio of the tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve is (2-4): (0.5-2): (2-4): (0.5-1): (89-95).

[0013] Preferably, the particle size is 2 to 4 mm.

[0014] Preferably, the drying temperature is 60-80° C., and the drying time is 5-8 hours.

[0015] Preferably, the calcining comprises:

[0016] The particles are first calcined at 300-500°C for 4-6 hours, and then calcined at 600-800°C for 2-4 hours.

[0017] Preferably, the calcining comprises:

[0018] The particles were calcined at 400 °C for 5 h and then at 700 °C for 3 h.

[0019] The second aspect of the present invention provides a catalyst for synthesizing diphenyl carbonate through ester exchange, which is prepared by the above-mentioned preparation method.

[0020] The third aspect of the present invention provides an application of a catalyst for synthesizing diphenyl carbonate through ester exchange prepared by the above preparation method in the synthesis of diphenyl carbonate.

[0021] Compared with the prior art, the beneficial effects of the present invention include at least:

[0022] The catalyst prepared by the specific process of the present invention has high catalytic efficiency through the limitation of various raw materials and process parameters, and can significantly improve the conversion efficiency of dimethyl carbonate and the selectivity of diphenyl carbonate. At the same time, the preparation method is simple in process and easy to produce, and the prepared catalyst has good stability and can be repeatedly recycled. DETAILED DESCRIPTION

[0023] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present invention.

[0024] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0025] This embodiment is a method for preparing a catalyst for synthesizing diphenyl carbonate by transesterification, and the preparation method comprises the following steps:

[0026] (a) mixing tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve to obtain a mixture;

[0027] (b) adding water to the mixture, granulating, and drying to obtain granules;

[0028] (c) calcining the particles to obtain the catalyst for synthesizing diphenyl carbonate by ester exchange reaction.

[0029] The catalyst prepared by the specific process of the present invention has high catalytic efficiency through the limitation of various raw materials and process parameters, and can significantly improve the conversion efficiency of dimethyl carbonate and the selectivity of diphenyl carbonate. At the same time, the preparation method is simple in process and easy to produce, and the prepared catalyst has good stability and can be repeatedly recycled.

[0030] In some embodiments, the mass ratio of tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve is (2-4): (0.5-2): (2-4): (0.5-1): (89-95).

[0031] In some embodiments, the particle size is 2 to 4 mm.

[0032] In some embodiments, the drying temperature is 60-80° C., and the drying time is 5-8 hours.

[0033] In some embodiments, the calcining comprises:

[0034] The particles are first calcined at 300-500°C for 4-6 hours, and then calcined at 600-800°C for 2-4 hours.

[0035] In some embodiments, the calcining comprises:

[0036] The particles were calcined at 400 °C for 5 h and then at 700 °C for 3 h.

[0037] Another embodiment of the present invention is a catalyst for synthesizing diphenyl carbonate through ester exchange, which is prepared by the above preparation method.

[0038] Another embodiment of the present invention is the use of a catalyst for synthesizing diphenyl carbonate through ester exchange prepared by the above preparation method in the synthesis of diphenyl carbonate.

[0039] The technical solution of the present invention is further described in detail below through specific embodiments.

[0040] Example 1

[0041] This embodiment is a method for preparing a catalyst for synthesizing diphenyl carbonate by transesterification, and the preparation method comprises the following steps:

[0042] (a) mixing tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve to obtain a mixture, wherein the mass ratio of tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve is 2:0.5:2:1:94.5;

[0043] (b) adding water to the mixture, granulating the mixture, and drying the mixture at 60° C. for 8 h to obtain granules having a particle size of 2 to 4 mm;

[0044] (c) The particles are first calcined at 300° C. for 6 h and then calcined at 800° C. for 4 h to obtain the catalyst for synthesizing diphenyl carbonate by ester exchange reaction.

[0045] Example 2

[0046] This embodiment is a method for preparing a catalyst for synthesizing diphenyl carbonate by transesterification, and the preparation method comprises the following steps:

[0047] (a) mixing tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve to obtain a mixture, wherein the mass ratio of tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve is 4:2:4:0.5:89.5;

[0048] (b) adding water to the mixture, granulating the mixture, and drying the mixture at 80° C. for 5 h to obtain granules having a particle size of 2 to 4 mm;

[0049] (c) The particles are first calcined at 500° C. for 4 h and then calcined at 800° C. for 2 h to obtain the catalyst for synthesizing diphenyl carbonate by ester exchange reaction.

[0050] Example 3

[0051] This embodiment is a method for preparing a catalyst for synthesizing diphenyl carbonate by transesterification, and the preparation method comprises the following steps:

[0052] (a) mixing tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve to obtain a mixture, wherein the mass ratio of tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve is 3:1:3:0.8:92.2;

[0053] (b) adding water to the mixture, granulating the mixture, and drying the mixture at 70° C. for 6 h to obtain granules having a particle size of 2 to 4 mm;

[0054] (c) The particles are first calcined at 400° C. for 5 h and then calcined at 700° C. for 3 h to obtain the catalyst for synthesizing diphenyl carbonate by ester exchange reaction.

[0055] Comparative Example 1

[0056] This comparative example is a method for preparing a catalyst for synthesizing diphenyl carbonate by transesterification, and the preparation method comprises the following steps:

[0057] (a) mixing tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve to obtain a mixture, wherein the mass ratio of tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve is 3:1:3:0.8:92.2;

[0058] (b) adding water to the mixture, granulating the mixture, and drying the mixture at 70° C. for 6 h to obtain granules having a particle size of 2 to 4 mm;

[0059] (c) calcining the particles at 700° C. for 8 h to obtain the catalyst for synthesizing diphenyl carbonate by ester exchange reaction.

[0060] Comparative Example 2

[0061] This comparative example is a method for preparing a catalyst for synthesizing diphenyl carbonate by transesterification, and the preparation method comprises the following steps:

[0062] (a) mixing tin oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve to obtain a mixture, wherein the mass ratio of tin oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve is 3:4:0.8:92.2;

[0063] (b) adding water to the mixture, granulating the mixture, and drying the mixture at 70° C. for 6 h to obtain granules having a particle size of 2 to 4 mm;

[0064] (c) calcining the particles at 700° C. for 8 h to obtain the catalyst for synthesizing diphenyl carbonate by ester exchange reaction.

[0065] Comparative Example 3

[0066] This comparative example is a method for preparing a catalyst for synthesizing diphenyl carbonate by transesterification, and the preparation method comprises the following steps:

[0067] (a) mixing tin oxide, molybdenum oxide, lithium hydroxide and ZSM molecular sieve to obtain a mixture, wherein the mass ratio of tin oxide, molybdenum oxide, lithium hydroxide and ZSM molecular sieve is 3:4:0.8:92.2;

[0068] (b) adding water to the mixture, granulating the mixture, and drying the mixture at 70° C. for 6 h to obtain granules having a particle size of 2 to 4 mm;

[0069] (c) calcining the particles at 700° C. for 8 h to obtain the catalyst for synthesizing diphenyl carbonate by ester exchange reaction.

[0070] Experimental example

[0071] The catalysts for synthesizing diphenyl carbonate by transesterification reaction prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were obtained respectively;

[0072] Under nitrogen protection, dimethyl carbonate, phenyl acetate and a catalyst were added into a reactor for ester exchange reaction at 150° C. for 8 hours, wherein the molar ratio of dimethyl carbonate to phenyl acetate was 1:2.2; and the mass ratio of the added amount of the catalyst to phenyl acetate was 5:100.

[0073] Different catalysts were used to prepare diphenyl carbonate according to the above method, and the conversion rate of dimethyl carbonate and the selectivity of diphenyl carbonate in the product were determined by chromatographic analysis; the results are shown in Table 1:

[0074] Table 1

[0075] Group Conversion rate of dimethyl carbonate (%) Selectivity (%) Example 1 91.6 98.3 Example 2 90.9 97.7 Example 3 92.1 98.5 Comparative Example 1 85.4 97.1 Comparative Example 2 77.8 81.6 Comparative Example 3 80.3 72.5

[0076] From Table 1, we can see that:

[0077] Compared with the comparative example, the catalyst for synthesizing diphenyl carbonate by ester exchange reaction prepared in the embodiment of the present application has a better catalytic effect, and can better improve the conversion efficiency of dimethyl carbonate and the selectivity of diphenyl carbonate. Specifically, compared with the comparative example, the technical scheme of the present application can more significantly improve the catalytic performance of the prepared catalyst by limiting the calcination temperature and the catalyst components, and improve the conversion rate and selectivity of the dimethyl carbonate conversion rate.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A method for preparing a catalyst for synthesizing diphenyl carbonate by transesterification, characterized in that: The preparation method comprises the following steps: (a) mixing tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve to obtain a mixture; (b) adding water to the mixture, granulating, and drying to obtain granules; (c) calcining the particles to obtain the catalyst for synthesizing diphenyl carbonate by ester exchange reaction.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the tin oxide, molybdenum oxide, titanium dioxide, lithium hydroxide and ZSM molecular sieve is (2-4): (0.5-2): (2-4): (0.5-1): (89-95).

3. The preparation method according to claim 1, characterized in that: The particle size of the particles is 2 to 4 mm.

4. The preparation method according to claim 1, characterized in that: The drying temperature is 60-80° C., and the drying time is 5-8 hours.

5. The preparation method according to claim 1, characterized in that: The roasting comprises: The particles are first calcined at 300-500°C for 4-6 hours, and then calcined at 600-800°C for 2-4 hours.

6. The preparation method according to claim 1, characterized in that: The roasting comprises: The particles were calcined at 400 °C for 5 h and then at 700 °C for 3 h.

7. A catalyst for synthesizing diphenyl carbonate through transesterification prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the catalyst for synthesizing diphenyl carbonate through ester exchange prepared by the preparation method according to any one of claims 1 to 6 in the synthesis of diphenyl carbonate.