Catalyst for preparing diphenyl carbonate as well as preparation method and application of catalyst

Abstract

The invention discloses a catalyst for preparing diphenyl carbonate as well as a preparation method and application of the catalyst, and belongs to the technical field of catalysts and preparation of diphenyl carbonate. The preparation method of diphenyl carbonate comprises the step of reacting dimethyl carbonate with phenol under the action of a catalyst to obtain diphenyl carbonate, the catalyst for preparing diphenyl carbonate comprises a carrier and an active component, and the mass percentage content of the carrier in the catalyst for preparing diphenyl carbonate is 90.0%-99.9%, and the mass percentage content of the active component in the catalyst for preparing diphenyl carbonate is 0.1%-10.0%. The carrier is carbon, and the active component is titanium; according to the method for preparing diphenyl carbonate, the granular catalyst is used as a filler of a reaction rectifying section, so that the reaction efficiency is further improved, the conversion rate of phenol is 68.7%, the total selectivity of ester exchange is 99.9%, and a better technical effect is achieved.

Description

Technical Field

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

[0002] Diphenyl carbonate (DPC) is a raw material for the preparation of polycarbonate by non-phosgene method. Its traditional preparation method is phosgene method, which is subject to policy restrictions due to the potential harm of highly toxic phosgene to the environment and production safety. The process of synthesizing diphenyl carbonate by transesterification reaction of phenol (PhOH) and dimethyl carbonate (DMC) under the action of catalyst avoids the use of highly toxic raw material phosgene. The main by-product methanol can also be recycled for the synthesis of starting raw material dimethyl carbonate. It is the green process route with the most promising industrialization prospects.

[0003] At present, homogeneous catalysts are often used to synthesize diphenyl carbonate by transesterification of dimethyl carbonate and phenol. Niu et al. [H. Niu et al., J. Mol. Catal. A 235 (2005) 240] used Cp 2 TiCl 2 As a catalyst, under optimized conditions, the conversion rate of phenol was 46.8% and the selectivity of diphenyl carbonate was 54.9%. H. Lee et al. [H. Lee et al., Catal. Today 87 (2003) 139] used Bu 2 SnO as catalyst, CF 3 SO 3 H is used as an auxiliary agent. Under optimized conditions, the conversion rate of dimethyl carbonate is 58.5%, and the yield of diphenyl carbonate is 18.3%. Many processes using titanium homogeneous catalysts have also achieved good results [D.Andre et al., US20100010252; P.Cao et al., J.Mol.Catal.(China)24(2010)492; J.Gao, Chin.J.Catal.22(2001)405]. Since homogeneous catalysts are difficult to separate from products and are not easy to reuse, heterogeneous catalysts are the main direction of future development.

[0004] Although heterogeneous catalysts are easy to separate from products, and their conversion rate and selectivity can basically reach the effect of homogeneous catalysts, the catalysts are easily deactivated and difficult to reuse. W. Zhou et al. [W. Zhou, et al, Appl. Catal. A, 260 (2004) 19-24] prepared a Pb-Zn bimetallic oxide catalyst. In the transesterification reaction of DMC and PhOH, the conversion rate of PhOH and the yield of DPC were 64.6% and 45.6%, respectively. However, after the catalyst was reused 4 times, the yield of DPC dropped to about 15%. The main reason for the catalyst deactivation is Pb 3 O 4 The disappearance of the crystal phase and the loss of Pb. YT Kim et al. [YT Kim, et al., Appl. Catal. A356 (2009) 211-215] loaded MoO 3 / SiO 2 and TiO 2 / SiO 2 The catalyst was used in the transesterification reaction of DMC and PhOH. It was found that after the catalyst was reused 5 times, the activity of the catalyst decreased by 95% and 66%, respectively. The author attributed the deactivation to the loss of Mo and Ti species, which was particularly serious under high temperature reactions. R. Tang et al. [R. Tang, et al., Chin. J. Catal., 35 (2014) 457-461] prepared SiO 2 Coated TiO 2 Core-shell catalysts. Summary of the invention

[0005] The present invention aims at solving the technical problem that the heterogeneous catalyst used in the existing preparation of diphenyl carbonate by ester exchange of dimethyl carbonate and phenol is easily deactivated and difficult to reuse. The present invention provides a catalyst for preparing diphenyl carbonate and a preparation method and application thereof. The catalyst used in the application has the characteristics of high activity, not easy to lose and high overall process efficiency.

[0006] To solve the above technical problems, the first aspect of the present invention provides a catalyst for preparing diphenyl carbonate, comprising a carrier and an active component, wherein the mass percentages of the carrier and the active component in the catalyst are: 90.0% to 99.9% of the carrier and 0.1% to 10.0% of the active component; the carrier is carbon, and the active component is titanium, wherein the titanium exists in the form of a single substance.

[0007] According to some embodiments of the present invention, the carbon is obtained by carbonizing a modified chloromethyl resin, and the modified chloromethyl resin is a modified chloromethyl styrene resin or a modified chloromethyl carboxylic acid resin;

[0008] And / or, the particle size of the catalyst is 0.1 mm to 3 mm.

[0009] The second aspect of the present invention provides a method for preparing the above-mentioned catalyst for preparing diphenyl carbonate, comprising the step of using a carrier to load the active component.

[0010] According to some embodiments of the present invention, the carrier is carbon, and the carbon is obtained by carbonizing a modified chloromethyl resin. Specifically, after the modified chloromethyl resin is loaded with an active component, it is subjected to high-temperature calcination, and during the calcination process, the modified chloromethyl resin is carbonized to generate carbon; when preparing the modified chloromethyl resin, the chloromethyl resin is mixed with a solvent, and a modifier is added to modify the modified chloromethyl resin; the modifier is a nitrogen-containing five-membered or six-membered heterocyclic aromatic compound, wherein the ring-forming skeleton of the five-membered or six-membered heterocyclic aromatic compound contains at least one nitrogen atom.

[0011] According to some embodiments of the present invention, the chloromethyl resin is a styrene-based or carboxylic acid-based resin; the particle size of the chloromethyl resin is 0.1 mm to 3 mm; preferably, the chloromethyl resin is spherical;

[0012] and / or, the modifier is at least one of piperazine, imidazole, 1-methylimidazole, and pyridine;

[0013] and / or, the solvent is at least one of toluene, methanol, ethanol, n-propanol, n-butanol, isobutanol or tert-butanol, tetrahydrofuran, dichloromethane, chloroform, N,N-dimethylformamide, ether and water;

[0014] and / or, the mass ratio of the chloromethyl resin to the solvent is 1:(1-10), preferably 1:(2-8), for example 1:4, 1:6, 1:8;

[0015] and / or, the mass ratio of the chloromethyl resin to the modifier is 1:(0.1-1.5), preferably 1:(0.15-1.2), for example 1:1, 1:0.8, 1:1.2;

[0016] And / or, before adding the modifier, a heating step is also included; the temperature after the heating is 30°C to 150°C, for example, 75°C, 80°C, 90°C;

[0017] And / or, the mixing and stirring rate is 50 rpm to 1000 rpm, such as 500 rpm or 800 rpm, and the stirring time is 1 h to 24 h, preferably 2 h to 18 h, such as 2 h or 8 h;

[0018] And / or, the modification time is 1 h to 24 h, for example 12 h;

[0019] And / or, after the modification, the process further comprises cooling, separating, washing the product, and drying the product; preferably, the drying temperature is 80°C to 180°C, such as 100°C or 120°C, and the drying time is 1h to 24h, such as 24h.

[0020] According to some embodiments of the present invention, when a carrier is used to load the active component, the carrier is mixed and stirred with a metal precursor solution containing the active component, dried, and then calcined in an inert gas atmosphere to obtain the catalyst.

[0021] According to some embodiments of the present invention, the metal precursor solution containing the active component is at least one of the soluble salts of titanium, and the mass concentration of the metal precursor solution containing the active component is 0.05% to 5%, for example, 0.855%, 1.71%, 4.3%; preferably, the soluble salt is selected from an inorganic acid salt or an organic acid salt.

[0022] According to some embodiments of the present invention, when a carrier is used to load an active component, the mass ratio of the carrier to the metal precursor solution containing the active component is 1:(1-10), preferably 1:(2-5), for example 1:4, 1:5;

[0023] And / or, after the carrier is mixed with the metal precursor solution containing the active component, a heating and stirring step is further included, wherein the heating temperature is 20°C to 100°C, for example, 30°C, 50°C, the stirring rate is 100 rpm to 800 rpm, for example, 400 rpm, 500 rpm, 600 rpm, 800 rpm, and the stirring time is 0.5h to 10h, for example, 2h, 6h, 8h;

[0024] And or, the drying temperature is 80°C to 180°C, for example 100°C, and the drying time is 1h to 48h, for example 24h;

[0025] and / or, the inert gas is nitrogen or argon;

[0026] And / or, the calcination temperature is 200°C to 1000°C, preferably 250°C to 800°C, such as 400°C, 500°C, and the calcination time is 1h to 48h, preferably 2h to 24h, such as 3h, 4h, 5h, 8h.

[0027] The third aspect of the present invention provides a method for preparing diphenyl carbonate, comprising the step of reacting dimethyl carbonate (DMC) and phenol under the action of a catalyst to obtain diphenyl carbonate; the catalyst is the catalyst for preparing diphenyl carbonate prepared by the above-mentioned preparation method.

[0028] According to some embodiments of the present invention, the reaction temperature is 150°C to 200°C, preferably 170°C to 190°C, for example 170°C, 175°C, 180°C, 190°C;

[0029] And / or, the reaction time is 1 h to 50 h, preferably 2 h to 48 h, preferably 10 h.

[0030] According to some embodiments of the present invention, the molar ratio of dimethyl carbonate to phenol is (2-8):1, preferably (2-6):1;

[0031] And / or, the mass ratio of the catalyst to phenol is 1:(1-20), for example, 1:2, 1:2.5, 1:3.3, 1:5, 1:10.

[0032] According to some embodiments of the present invention, the reaction adopts a distillation method, and the distillation section includes a catalyst layer and a packing layer; preferably, the height ratio of the catalyst layer to the packing layer is (0.05-1):1, preferably (0.1-1):1, for example, 0.1:1, 0.2:1, 0.25:1, 0.3:1; wherein the particle size of the catalyst is 0.1mm~3mm, and the particle size of the packing is 1mm~30mm; and / or the distillation reflux ratio is 1-3, for example, 1.

[0033] Beneficial effects:

[0034] The method for preparing diphenyl carbonate by ester exchange reaction of dimethyl carbonate and phenol can solve the problems of difficult separation of general homogeneous catalysts, low activity and loss of heterogeneous catalysts. Catalyst particles used for preparing diphenyl carbonate are used as fillers in a reaction and rectification section, which provides more reaction intervals compared with a conventional filler section, thereby further improving the reaction efficiency. When the reaction temperature is 180°C, the molar ratio of dimethyl carbonate to phenol is 2, the dimethyl carbonate dropwise addition time is 10 hours, the mass ratio of the catalyst used for preparing diphenyl carbonate to phenol is 1:5, and the height ratio of the catalyst layer to the filler layer in the reaction and rectification section is 0.2:1, the conversion rate of phenol is 68.7%, and the total selectivity of ester exchange is 99.9%, thereby achieving good technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a scanning electron microscope image of the catalyst C1 prepared in Example 1 of the present invention;

[0036] Figure 2 This is a scanning electron microscope image of the catalyst S2 prepared in Comparative Example 2 of the present invention;

[0037] Figure 3 This is a transmission electron microscope image of the catalyst C1 prepared in Example 1 of the present invention;

[0038] Figure 4 This is a transmission electron microscope image of catalyst S2 prepared in comparative example 2 of the present invention. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the embodiments, but the present invention is not limited by these embodiments.

[0040] The gas chromatograph in the present invention is an Agilent 7890 chromatograph. The analysis conditions are: chromatographic column HP-FFAP, injection port temperature 250°C, FID detector, column box program heating, 50°C maintained for 3 minutes, then heated to 230°C at 10°C / min and maintained for 10 minutes, split ratio 50:1, and component content analysis was performed using the calibration normalization method.

[0041] The conversion rate of phenol in the present invention is calculated as follows: (mass of input phenol - mass of product after reaction * phenol content) / mass of input phenol * 100%.

[0042] The total selectivity of the transesterification in the present invention is calculated as follows: total material after the reaction*(mass fraction of diphenyl carbonate*94 / 214+mass fraction of methyl phenyl carbonate*94 / 153) / mass fraction of converted phenol*100%.

[0043] Example 1

[0044] This embodiment provides a method for preparing diphenyl carbonate:

[0045] Preparation of a catalyst for preparing diphenyl carbonate: In a 500 ml three-necked flask, 50 g of chloromethylstyrene resin and 200 g of N,N-dimethylformamide were added, and the mixture was stirred at a rate of 500 rpm for 8 h, and the temperature was raised to 90° C., 50 g of imidazole was added, and the mixture was kept warm for reaction for 12 h, and the product was separated after cooling, and then washed with deionized water, and the product was dried at a temperature of 100° C. for 24 h to obtain a modified resin; then in another 500 ml three-necked flask, 50 g of the modified resin and 200 g of an aqueous solution of 1.71 g of titanium sulfate were added, and the mixture was stirred at a rate of 500 rpm for 6 h at a temperature of 30° C., and the mixture was placed in an oven and dried at a temperature of 100° C. for 24 h, and then transferred to a muffle furnace, and calcined at a temperature of 500° C. for 5 h under a nitrogen atmosphere to obtain a catalyst C1, in which the mass percentage of titanium in C1 is 1.0%. The scanning electron microscope image of C1 is as shown in FIG. Figure 1 As shown, the transmission electron microscope image of C1 is as follows Figure 3 shown.

[0046] During the catalyst preparation process, the chloromethylstyrene resin was spherical with a particle size of 0.5 mm.

[0047] Preparation of diphenyl carbonate: In a 1000ml three-necked flask equipped with an air guide tube, a temperature-controlling thermocouple, a constant pressure dropping funnel and a distillation column, 10.0g of catalyst C1 and 100.0g (1.06mol) of phenol were added, heated to 180°C, and 191.5g of DMC (2.13mol) was added dropwise for 15h. While adding dropwise, the azeotrope of DMC and methanol was distilled out through the distillation column, and the reflux ratio was 1. After the addition was completed, the reaction was continued at 180°C for 10h, and the disproportionated product DMC was distilled out through the distillation column. After the reaction was completed, chromatographic analysis was performed. The calculation results showed that the phenol conversion rate was 68.7% and the total selectivity of the ester exchange was 99.9%.

[0048] In the preparation of the above diphenyl carbonate, the lower middle section of the lower layer of the distillation section is a catalyst layer, weighing 10g and 20cm high, and the upper section is a glass filler layer, 100cm high. The height ratio of the catalyst layer and the filler layer in the distillation column is 0.2:1, wherein the particle size of the catalyst is 0.5mm, and the long side particle size of the glass is 20mm; the mass of the catalyst filled in the distillation column is 50% of the total amount of the catalyst; the molar ratio of dimethyl carbonate to phenol is 2:1; and the mass ratio of the catalyst to phenol is 1:5.

[0049] Example 2

[0050] This embodiment provides a method for preparing diphenyl carbonate:

[0051] Preparation of a catalyst for preparing diphenyl carbonate: In a 500ml three-necked flask, 50g of chloromethylstyrene resin and 300g of N,N-dimethylformamide were added, and the mixture was stirred at a rate of 800 rpm for 2h, the temperature was raised to 80°C, 40g of imidazole was added, the mixture was kept warm for reaction for 12h, the product was separated after cooling, and the product was washed with deionized water, and then dried at a temperature of 120°C for 24h to obtain a modified resin; then in another 500ml three-necked flask, 50g of the modified resin and 200g of an aqueous solution of 1.71g of titanium sulfate were added, and the mixture was stirred at a rate of 800 rpm for 8h at a temperature of 50°C, the mixture was placed in an oven and dried at a temperature of 100°C for 24h, and then the mixture was transferred to a muffle furnace and calcined at a temperature of 400°C for 8h under a nitrogen atmosphere to obtain a catalyst C2, wherein the mass percentage of titanium in C2 is 1.0%.

[0052] During the catalyst preparation process, the chloromethylstyrene resin was spherical with a particle size of 0.7 mm.

[0053] Preparation of diphenyl carbonate: 10.0 g of catalyst C2 and 100.0 g of phenol (1.06 mol) were added to a 1000 ml three-necked flask equipped with an air guide tube, a temperature-controlling thermocouple, a constant pressure dropping funnel and a distillation column, and the mixture was heated to 180°C. 287.2 g of DMC (3.2 mol) was added dropwise for 10 hours. The azeotropic mixture of DMC and methanol was distilled out through the distillation column at a reflux ratio of 1. After the addition was completed, the reaction was continued at 180°C for 10 hours, and the disproportionated product DMC was distilled out through the distillation column. After the reaction was completed, chromatographic analysis was performed. The calculation results showed that the phenol conversion rate was 76.5% and the total selectivity of the transesterification was 99.9%.

[0054] In the preparation of the above diphenyl carbonate, the lower middle section of the lower layer of the distillation section is a catalyst layer, weighing 10g and 20cm high, and the upper section is a glass filler layer, 200cm high. The height ratio of the catalyst layer and the filler layer in the distillation column is 0.1:1, wherein the particle size of the catalyst is 0.7mm and the long side particle size of the glass is 10mm; the mass of the catalyst filled in the distillation column is 50% of the total amount of the catalyst; the molar ratio of dimethyl carbonate to phenol is 2:1; and the mass ratio of the catalyst to phenol is 1:5.

[0055] Example 3

[0056] This embodiment provides a method for preparing diphenyl carbonate:

[0057] Preparation of a catalyst for preparing diphenyl carbonate: In a 500ml three-necked flask, 50g of chloromethylstyrene resin and 300g of N,N-dimethylformamide were added, and the mixture was stirred at a rate of 500 rpm for 2h, the temperature was raised to 75°C, 40g of 1-methylimidazole was added, the mixture was kept warm for reaction for 12h, the product was separated after cooling, and the product was washed with deionized water, and then dried at a temperature of 100°C for 24h to obtain a modified resin; then in another 500ml three-necked flask, 50g of the modified resin and 200g of an aqueous solution of 1.71g of titanium sulfate were added, and the mixture was stirred at a rate of 400 rpm for 8h at a temperature of 50°C, the mixture was placed in an oven and dried at a temperature of 100°C for 24h, and then the mixture was transferred to a muffle furnace and calcined at a temperature of 500°C for 4h under a nitrogen atmosphere to obtain a catalyst C3, wherein the mass percentage of titanium in C3 is 1.0%.

[0058] During the catalyst preparation process, the chloromethylstyrene resin was spherical with a particle size of 0.8 mm.

[0059] Preparation of diphenyl carbonate: 25.0g of catalyst C3 and 100.0g (1.06mol) of phenol were added to a 1000ml three-necked flask equipped with an air guide tube, a temperature-controlling thermocouple, a constant pressure dropping funnel and a distillation column, and the mixture was heated to 180°C. 383g of DMC (4.25mol) was added dropwise for 20h. The azeotropic mixture of DMC and methanol was distilled out through the distillation column at a reflux ratio of 1. After the addition was completed, the reaction was continued at 175°C for 10h, and the disproportionated product DMC was distilled out through the distillation column. After the reaction was completed, chromatographic analysis was performed. The calculation results showed that the phenol conversion rate was 78.7% and the total selectivity of the transesterification was 99.9%.

[0060] In the preparation of the above diphenyl carbonate, the lower middle section of the lower layer of the distillation section is a catalyst layer, weighing 25g and 50cm high, and the upper section is a glass filler layer, 150cm high. The height ratio of the catalyst layer and the filler layer in the distillation column is 0.3:1, wherein the particle size of the catalyst is 0.8mm and the long side particle size of the glass is 20mm; the mass of the catalyst filled in the distillation column is 50% of the total amount of the catalyst; the molar ratio of dimethyl carbonate to phenol is 4:1; and the mass ratio of the catalyst to phenol is 1:2.

[0061] Example 4

[0062] This embodiment provides a method for preparing diphenyl carbonate:

[0063] Preparation of a catalyst for preparing diphenyl carbonate: In a 500ml three-necked flask, 50g of chloromethylstyrene resin and 400g of toluene are added, and the mixture is stirred at a rate of 500 rpm for 2h, the temperature is raised to 75°C, 40g of 1-methylimidazole is added, the mixture is kept warm for reaction for 12h, the product is separated after cooling, and the product is washed with deionized water, and then dried at a temperature of 100°C for 24h to obtain a modified resin; then in another 500ml three-necked flask, 50g of the modified resin and 200g of an aqueous solution prepared with 1.71g of titanium sulfate are added, and the mixture is stirred at a rate of 500 rpm for 2h at a temperature of 50°C, the mixture is placed in an oven and dried at a temperature of 100°C for 24h, and then transferred to a muffle furnace and calcined at a temperature of 500°C for 4h under a nitrogen atmosphere to obtain a catalyst C4, wherein the mass percentage of titanium in C4 is 1.0%.

[0064] During the catalyst preparation process, the chloromethylstyrene resin was spherical with a particle size of 0.9 mm.

[0065] Preparation of diphenyl carbonate: 30.0g of catalyst C4 and 100.0g (1.06mol) of phenol were added to a 1000ml three-necked flask equipped with an air guide tube, a temperature-controlling thermocouple, a constant pressure dropping funnel and a distillation column, and the mixture was heated to 180°C. 574g of DMC (6.4mol) was added dropwise for 24h. The azeotropic mixture of DMC and methanol was distilled out through the distillation column at a reflux ratio of 1. After the addition was completed, the reaction was continued at 170°C for 10h, and the disproportionated product DMC was distilled out through the distillation column. After the reaction was completed, chromatographic analysis was performed. The calculation results showed that the phenol conversion rate was 84.7% and the total selectivity of the transesterification was 99.9%.

[0066] In the preparation of the above diphenyl carbonate, the lower middle section of the lower layer of the distillation section is a catalyst layer, weighing 10g and 20cm high, and the upper section is a glass filler layer, 80cm high. The height ratio of the catalyst layer and the filler layer in the distillation column is 0.25:1, wherein the particle size of the catalyst is 0.9mm and the long side particle size of the glass is 20mm; the mass of the catalyst filled in the distillation column is 25% of the total amount of the catalyst; the molar ratio of dimethyl carbonate to phenol is 6:1; and the mass ratio of the catalyst to phenol is 1:2.5.

[0067] Example 5

[0068] This embodiment provides a method for preparing diphenyl carbonate:

[0069] Preparation of a catalyst for preparing diphenyl carbonate: In a 500ml three-necked flask, 50g of chloromethylstyrene resin and 400g of toluene are added, and the mixture is stirred at a rate of 500 rpm for 2h, the temperature is raised to 75°C, 40g of 1-methylimidazole is added, the mixture is kept warm for reaction for 12h, the product is separated after cooling, and the product is washed with deionized water, and then dried at a temperature of 100°C for 24h to obtain a modified resin; then in another 500ml three-necked flask, 50g of the modified resin and 200g of an aqueous solution prepared with 3.42g of titanium sulfate are added, and the mixture is stirred at a rate of 600 rpm for 2h at a temperature of 50°C, the mixture is placed in an oven and dried at a temperature of 100°C for 24h, and then the mixture is transferred to a muffle furnace and calcined at a temperature of 500°C for 4h under a nitrogen atmosphere to obtain a catalyst C5, wherein the mass percentage of titanium in C5 is 2.0%.

[0070] During the catalyst preparation process, the chloromethylstyrene resin was spherical with a particle size of 0.9 mm.

[0071] Preparation of diphenyl carbonate: 20.0g of catalyst C5 and 100.0g (1.06mol) of phenol were added to a 1000ml three-necked flask equipped with an air guide tube, a temperature-controlling thermocouple, a constant pressure dropping funnel and a distillation column, and the mixture was heated to 180°C. 287.2g of DMC (3.2mol) was added dropwise for 8h. The azeotropic mixture of DMC and methanol was distilled out through the distillation column at a reflux ratio of 1. After the addition was completed, the reaction was continued at 180°C for 10h, and the disproportionated product DMC was distilled out through the distillation column. After the reaction was completed, chromatographic analysis was performed. The calculation results showed that the phenol conversion rate was 74.3% and the total selectivity of the transesterification was 99.9%.

[0072] In the preparation of the above diphenyl carbonate, the lower middle section of the lower layer of the distillation section is a catalyst layer, weighing 10g and 20cm high, and the upper section is a glass filler layer, 80cm high. The height ratio of the catalyst layer and the filler layer in the distillation column is 0.25:1, wherein the particle size of the catalyst is 0.9mm and the long side particle size of the glass is 20mm; the mass of the catalyst filled in the distillation column is 33% of the total amount of the catalyst; the molar ratio of dimethyl carbonate to phenol is 3:1; and the mass ratio of the catalyst to phenol is 1:3.3.

[0073] Example 6

[0074] This embodiment provides a method for preparing diphenyl carbonate:

[0075] Preparation of a catalyst for preparing diphenyl carbonate: In a 500ml three-necked flask, 50g of chloromethylstyrene resin and 400g of toluene are added, and the mixture is stirred at a rate of 500 rpm for 2h, the temperature is raised to 75°C, 60g of 1-methylimidazole is added, the mixture is kept warm for reaction for 12h, the product is separated after cooling, and the product is washed with deionized water, and then dried at a temperature of 100°C for 24h to obtain a modified resin; then in another 500ml three-necked flask, 50g of the modified resin and 250g of an aqueous solution of 8.6g of titanium sulfate are added, the mixture is stirred at a rate of 600 rpm for 2h at a temperature of 50°C, the mixture is placed in an oven and dried at a temperature of 100°C for 24h, and then the mixture is transferred to a muffle furnace and calcined at a temperature of 500°C for 4h under a nitrogen atmosphere to obtain a catalyst C6, wherein the mass percentage of titanium in C6 is 5.0%.

[0076] During the catalyst preparation process, the chloromethylstyrene resin was spherical with a particle size of 0.9 mm.

[0077] Preparation of diphenyl carbonate: 30.0 g of catalyst C6 and 100.0 g (1.06 mol) of phenol were added to a 1000 ml three-necked flask equipped with an air guide tube, a temperature-controlling thermocouple, a constant pressure dropping funnel and a distillation column, and the mixture was heated to 190° C. Then, 287.2 g of DMC (3.2 mol) was added dropwise for 8 hours. While adding dropwise, the azeotropic product of DMC and methanol was distilled out through the distillation column, and the reflux ratio was 1. After the addition, the reaction was continued at 190° C. for 10 hours, and the disproportionated product DMC was distilled out through the distillation column. After the reaction was completed, chromatographic analysis was performed, and the calculation results showed that the phenol conversion rate was 88.5% and the total selectivity of the transesterification was 99.9%.

[0078] In the preparation of the above diphenyl carbonate, the lower middle section of the lower layer of the distillation section is a catalyst layer, weighing 20g and 40cm high, and the upper section is a glass filler layer, 80cm high. The height ratio of the catalyst layer and the filler layer in the distillation column is 0.5:1, wherein the particle size of the catalyst is 0.9mm and the long side particle size of the glass is 20mm; the mass of the catalyst filled in the distillation column is 40% of the total amount of the catalyst; the molar ratio of dimethyl carbonate to phenol is 3:1; and the mass ratio of the catalyst to phenol is 1:2.

[0079] Comparative Example 1

[0080] This comparative example provides a method for preparing diphenyl carbonate:

[0081] Preparation of a catalyst for preparing diphenyl carbonate: In a 500 ml three-necked flask, 50 g of chloromethylstyrene resin and 200 g of N,N-dimethylformamide were added, and the mixture was stirred at a rate of 500 rpm for 8 h. The temperature was raised to 90° C., 50 g of imidazole was added, and the mixture was kept warm for reaction for 12 h. The product was separated after cooling, and then washed with deionized water. The product was dried at a temperature of 100° C. for 24 h to obtain a modified resin; then, in another 500 ml three-necked flask, 50 g of the modified resin and 200 g of an aqueous solution of 1.71 g of titanium sulfate were added, and the mixture was stirred at a rate of 500 rpm for 6 h at a temperature of 30° C., and the mixture was placed in an oven and dried at a temperature of 100° C. for 24 h. The mixture was then transferred to a muffle furnace and calcined at a temperature of 500° C. for 5 h under a nitrogen atmosphere to obtain a catalyst S1, wherein the mass percentage of titanium in S1 is 1.0%.

[0082] During the catalyst preparation process, the chloromethylstyrene resin was spherical with a particle size of 0.5 mm.

[0083] Preparation of diphenyl carbonate: In a 1000ml three-necked flask equipped with an air guide tube, a temperature-controlling thermocouple, a constant pressure dropping funnel and a distillation column, 10.0g of catalyst S1 and 100.0g (1.06mol) of phenol were added, heated to 180°C, and 191.5g of DMC (2.13mol) was added dropwise for 15h. While adding dropwise, the azeotrope of DMC and methanol was distilled out through the distillation column, and the reflux ratio was 1. After the addition was completed, the reaction was continued at 180°C for 10h, and the disproportionated product DMC was distilled out through the distillation column. After the reaction was completed, chromatographic analysis was performed. The calculation results showed that the phenol conversion rate was 45.9% and the total selectivity of the ester exchange was 99.9%.

[0084] In the preparation of diphenyl carbonate, the distillation section is a glass packing layer with a height of 100 cm, wherein the long side particle diameter of the glass is 20 mm; the molar ratio of dimethyl carbonate to phenol is 2:1; and the mass ratio of the catalyst to phenol is 1:10.

[0085] Comparative Example 2

[0086] This comparative example provides a method for preparing diphenyl carbonate:

[0087] Preparation of a catalyst for preparing diphenyl carbonate: In a 500 ml three-necked flask, add 50 g of chloromethyl resin and 1.71 g of titanium sulfate to prepare an aqueous solution of 200 g, stir at a temperature of 30° C. at a rate of 500 rpm for 6 h, put into an oven at a temperature of 100° C. and dry for 24 h, then transfer to a muffle furnace and calcine at a temperature of 500° C. for 5 h in a nitrogen atmosphere to obtain a catalyst S2. The mass percentage of titanium in S2 is 1.0%. The scanning electron microscope image of S2 is as follows Figure 3 The transmission electron microscopy image of S2 is shown in Figure 4 shown.

[0088] During the catalyst preparation process, the chloromethylstyrene resin was spherical with a particle size of 0.5 mm.

[0089] Preparation of diphenyl carbonate: In a 1000ml three-necked flask equipped with an air guide tube, a temperature-controlling thermocouple, a constant pressure dropping funnel and a distillation column, 10.0g of catalyst S2 and 100.0g (1.06mol) of phenol were added, heated to a temperature of 180°C, and 91.5g of DMC (2.13mol) was added dropwise for 15h. While adding dropwise, the azeotrope of DMC and methanol was distilled out through the distillation column, and the reflux ratio was 1. After the addition was completed, the reaction was continued at a temperature of 180°C for 10h, and the disproportionated product DMC was distilled out through the distillation column. After the reaction was completed, chromatographic analysis was performed, and the calculation results showed that the phenol conversion rate was 39.5% and the total selectivity of the ester exchange was 99.9%.

[0090] In the preparation of the above diphenyl carbonate, the lower middle section of the lower layer of the distillation section is a catalyst layer, weighing 10g and 20cm high, and the upper section is a glass filler layer, 100cm high. The height ratio of the catalyst layer and the filler layer in the distillation column is 0.2:1, wherein the particle size of the catalyst is 0.5mm, and the long side particle size of the glass is 20mm; the mass of the catalyst filled in the distillation column is 50% of the total amount of the catalyst; the molar ratio of dimethyl carbonate to phenol is 2:1; and the mass ratio of the catalyst to phenol is 1:5.

[0091] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A catalyst for preparing diphenyl carbonate, comprising a carrier and an active component, characterized in that: The mass percentages of the carrier and the active component in the catalyst are: 90.0% to 99.9% of the carrier and 0.1% to 10.0% of the active component; the carrier is carbon and the active component is titanium; the carbon is obtained by carbonizing modified chloromethyl resin.

2. The catalyst according to claim 1, characterized in that The modified chloromethyl resin is a modified chloromethyl styrene resin or a modified chloromethyl carboxylic acid resin; And / or, the particle size of the catalyst is 0.1 mm to 3 mm.

3. A method for preparing a catalyst for preparing diphenyl carbonate according to claim 1 or 2, characterized in that: The preparation method comprises the steps of using a carrier to load an active component. When preparing the modified chloromethyl resin, the chloromethyl resin is mixed with a solvent, a modifier is added, and the modified chloromethyl resin is obtained by modification. The modifier is a nitrogen-containing five-membered or six-membered heterocyclic aromatic compound.

4. The preparation method according to claim 3, characterized in that: The chloromethyl resin is a styrene-based or carboxylic acid-based resin; the particle size of the chloromethyl resin is 0.1 mm to 3 mm; preferably, the chloromethyl resin is spherical; and / or, the modifier is at least one of piperazine, imidazole, 1-methylimidazole, and pyridine; and / or, the solvent is at least one of toluene, methanol, ethanol, n-propanol, n-butanol, isobutanol or tert-butanol, tetrahydrofuran, dichloromethane, chloroform, N,N-dimethylformamide, ether and water; And / or, the mass ratio of the chloromethyl resin to the solvent is 1:(1-10), preferably 1:(2-8); And / or, the mass ratio of the chloromethyl resin to the modifier is 1:(0.1-1.5), preferably 1:(0.15-1.2); And / or, before adding the modifier, a heating step is also included; the temperature after the heating is 30°C to 150°C; And / or, the mixing and stirring rate is 50 rpm to 1000 rpm, and the stirring time is 1 h to 24 h, preferably 2 h to 18 h; and / or, the modification time is 1h to 24h; And / or, after the modification, the process further comprises the steps of cooling, separating, washing the product, and drying the product; preferably, the drying temperature is 80° C. to 180° C., and the drying time is 1 hour to 24 hours.

5. The preparation method according to claim 3 or 4, characterized in that: When the active component is loaded on a carrier, the carrier is mixed with a metal precursor solution containing the active component, stirred, dried, and then calcined in an inert gas atmosphere to obtain the catalyst.

6. The preparation method according to claim 5, characterized in that: The metal precursor solution containing the active component is at least one of the soluble salt solutions of titanium, and the mass concentration of the metal precursor solution containing the active component is 0.05% to 5%; preferably, the soluble salt is selected from inorganic acid salts or organic acid salts.

7. The preparation method according to any one of claims 3 to 6, characterized in that: When the active component is loaded on a carrier, the mass ratio of the carrier to the metal precursor solution containing the active component is 1:(1-10), preferably 1:(2-5); And / or, after the carrier is mixed with the metal precursor solution containing the active component, a heating and stirring step is further included, wherein the heating temperature is 20° C. to 100° C., the stirring rate is 100 rpm to 800 rpm, and the stirring time is 0.5 h to 10 h; And or, the drying temperature is 80°C to 180°C, and the drying time is 1h to 48h; and / or, the inert gas is nitrogen or argon; And / or, the calcination temperature is 200°C to 1000°C, preferably 250°C to 800°C, and the calcination time is 1h to 48h, preferably 2h to 24h.

8. A method for preparing diphenyl carbonate, characterized in that: The method comprises the step of reacting dimethyl carbonate and phenol under the action of a catalyst to obtain diphenyl carbonate; the catalyst is the catalyst for preparing diphenyl carbonate according to claim 1 or 2, or the catalyst for preparing diphenyl carbonate prepared by any preparation method in claims 3-7.

9. The method according to claim 8, characterized in that The reaction temperature is 150°C to 200°C, preferably 170°C to 190°C; And / or, the reaction time is 1 h to 50 h, preferably 2 h to 48 h.

10. The method according to claim 8, characterized in that The molar ratio of dimethyl carbonate to phenol is (2-8):1, preferably (2-6):1; And / or, the mass ratio of the catalyst to phenol is 1:(1-20).

11. The method according to claim 8, characterized in that The reaction adopts distillation, and the distillation section includes a catalyst layer and a packing layer; preferably, the height ratio of the catalyst layer to the packing layer is (0.05-1):1, preferably (0.1-1):1; wherein the particle size of the catalyst is 0.1mm~3mm, and the particle size of the packing is 1mm~30mm; and / or the distillation reflux ratio is 1-3.

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