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CN-122010735-A - Method and system for efficiently synthesizing diphenyl carbonate

CN122010735ACN 122010735 ACN122010735 ACN 122010735ACN-122010735-A

Abstract

The invention relates to the technical field of organic chemical synthesis, in particular to a method and a system for efficiently synthesizing diphenyl carbonate. The method comprises the steps of taking phenol and carbonic ester as raw materials, taking a polymetallic vanadium oxide compound as a catalyst, reacting in a high-temperature reaction kettle with a mechanical stirring and condensing reflux device and a kettle bottom gas distributor, continuously injecting carbonic ester into the kettle bottom of the high-temperature reaction kettle along with inert carrier gas, refluxing unreacted carbonic ester through fractional condensation, and discharging byproduct alcohol along with the inert carrier gas, wherein the carbonic ester is dimethyl carbonate or diethyl carbonate, and the dosage of the catalyst is 0.5-5wt% of the mass of the phenol raw material. The invention realizes 'selective condensation reflux of raw materials (carbonic ester) and selective removal of byproducts (alcohol) through continuous feeding and specific condensation temperature control', effectively breaks the reversible balance of transesterification, greatly promotes forward reaction, and remarkably improves the conversion rate of phenol and the reaction efficiency.

Inventors

  • SHI FENG
  • YUAN HANGKONG
  • CUI XINJIANG
  • WANG BIN
  • QIAN BO
  • HE DONGCHENG

Assignees

  • 中国科学院兰州化学物理研究所

Dates

Publication Date
20260512
Application Date
20260410

Claims (10)

  1. 1. A method for efficiently synthesizing diphenyl carbonate is characterized in that phenol and carbonic ester are used as raw materials, a polymetallic vanadium-oxygen compound is used as a catalyst, and the raw materials react in a high-temperature reaction kettle with a mechanical stirring, condensing reflux device and a kettle bottom gas distributor; The carbonic ester is dimethyl carbonate or diethyl carbonate; the catalyst is used in an amount of 0.5-5wt% of the mass of the phenol raw material.
  2. 2. The method for efficiently synthesizing diphenyl carbonate according to claim 1, which is characterized by comprising the following specific steps: S1, feeding and replacing, namely adding phenol and a catalyst into a high-temperature reaction kettle in advance, opening an inert carrier gas valve, introducing inert carrier gas from a gas distributor, carrying out gas replacement on the high-temperature reaction kettle, and exhausting air; S2, heating, namely starting stirring and heating a high-temperature reaction kettle in an inert carrier gas atmosphere, and heating to 120-180 ℃; s3, continuously feeding and reacting, namely pumping liquid carbonic ester through a metering pump, merging the liquid carbonic ester with inert carrier gas from the bottom, and continuously injecting the liquid carbonic ester into the bottom of a liquid layer of the high-temperature reaction kettle in a bubbling mode through a gas distributor; S4, removing and refluxing a product, namely quickly heating and vaporizing a carbonate gas-liquid mixture injected into the bottom of a liquid layer of the high-temperature reaction kettle under the stirring action, fully contacting carbonate steam and phenol liquid on the surface of a catalyst in the rising process to generate transesterification reaction, and enabling the generated by-product alcohol and unreacted carbonate steam to enter a condensation reflux device together with inert carrier gas; S5, condensation separation, namely, realizing selective separation and reflux of products by controlling the condensation temperature of a condensation reflux device, condensing and refluxing carbonate steam to a high-temperature reaction kettle for continuous reaction, and enabling byproduct alcohol to enter a subsequent collecting device along with inert carrier gas; and S6, stopping feeding when the phenol conversion rate is monitored to reach the preset requirement, and ending the reaction.
  3. 3. The method for efficiently synthesizing diphenyl carbonate according to claim 2, wherein the molar ratio of the injection rate of the carbonic ester to the initial amount of phenol in the high-temperature reaction kettle in the step S3 is controlled to be 0.025-0.125 mol/mol/h, and the ratio of the flow rate of the inert carrier gas to the initial amount of phenol in the kettle is controlled to be 300-2000 mL/mol/h.
  4. 4. The method for efficiently synthesizing diphenyl carbonate according to claim 2, wherein the step S3 is characterized in that the carbonic ester is continuously fed for 4-20 hours, and the molar ratio of the cumulatively fed carbonic ester to the initial phenol is greater than 0.5:1.
  5. 5. The method for efficiently synthesizing diphenyl carbonate according to claim 2, wherein in the step S5, the condensing temperature is 70-80 ℃ when the raw material is dimethyl carbonate, and 90-100 ℃ when the raw material is diethyl carbonate.
  6. 6. The method for efficient synthesis of diphenyl carbonate according to any one of claims 1 to 5, wherein the multi-metal vanadium oxide complex is MVO x , wherein M comprises at least two metal elements of Fe, bi, al, zn, ni, zr; the multi-metal vanadium oxide compound is prepared by a hydrothermal method, and the specific preparation process is as follows: 1) Preparing raw materials, namely preparing ammonium vanadate solution by taking ammonium vanadate as a vanadium source, and preparing metal salt solution by taking a nitrate mixture as a metal source; 2) Mixing and adjusting, namely dripping a metal salt solution into an ammonium vanadate solution, uniformly stirring, and adjusting the pH value of a mixed system to a range of 2-7 by adopting a NaOH solution; 3) The hydrothermal reaction is carried out, namely the mixed system with the pH value adjusted is placed in a hydrothermal environment, the hydrothermal temperature is controlled to be 160-200 ℃, and the reaction time is 6-24 hours; 4) And (3) post-treatment, namely centrifugally separating a product after the hydrothermal reaction, washing with clear water, drying for 6-12 hours at 80-100 ℃, and roasting for 2-4 hours at 200-300 ℃ to obtain the multi-metal vanadium-oxygen compound.
  7. 7. The method for efficiently synthesizing diphenyl carbonate according to claim 6, wherein the concentration of the metal salt solution is 0.1 to 0.5mol/L; The molar ratio of the total metal ions to vanadium in the nitrate mixture is 0.5-1.3:1.
  8. 8. The method for efficiently synthesizing diphenyl carbonate according to claim 6, wherein the dropping rate of the metal salt solution into the ammonium vanadate solution is 1-5 ml/min, the stirring rate is 300-500 r/min, and the stirring time is 30-60 min.
  9. 9. The system for efficiently synthesizing diphenyl carbonate is characterized by comprising a high-temperature reaction kettle, a condensation reflux device and a gas distributor, wherein the condensation reflux device is arranged at the top of the high-temperature reaction kettle, and the gas distributor is arranged at the bottom of the high-temperature reaction kettle; the bottom of the high-temperature reaction kettle is also provided with an air inlet pipeline and a feeding pipeline, the air inlet pipeline is communicated with the gas distributor, and the feeding pipeline and the air inlet pipeline are converged before entering the gas distributor.
  10. 10. The system for efficiently synthesizing diphenyl carbonate according to claim 9, wherein a jacket heating device is arranged outside the high-temperature reaction kettle, and a mechanical stirring device is arranged inside the high-temperature reaction kettle; a bottom detection sampling tube is also arranged in the high-temperature reaction kettle; the system for efficiently synthesizing diphenyl carbonate also comprises a secondary condenser and a secondary condensation collecting device, wherein the secondary condenser is communicated with the condensation reflux device, and the secondary condensation collecting device is communicated with the secondary condenser.

Description

Method and system for efficiently synthesizing diphenyl carbonate Technical Field The invention relates to the technical field of organic chemical synthesis, in particular to a method and a system for efficiently synthesizing diphenyl carbonate. Background Diphenyl carbonate is one of the key raw materials for synthesizing polycarbonate, and the green and clean production process of the diphenyl carbonate has important significance for the development of a non-phosgene synthetic route of polycarbonate. The preparation of diphenyl carbonate (DPC) by transesterification is currently a very representative process route and is recognized as one of the typical examples of green sustainable production in the chemical industry. The traditional transesterification synthesis of DPC mostly adopts kettle type batch or semi-batch operation, and raw materials are added at one time or in batches. The method has the following defects that (1) the reaction is a reversible equilibrium reaction, if the generated methanol or ethanol is not removed in time, the forward reaction is inhibited, the phenol conversion rate and DPC selectivity are lower, (2) the catalyst is easy to deactivate and difficult to separate from the product in the reaction process, (3) the reaction materials are insufficiently mixed, the reaction efficiency is required to be improved, and (4) the removal of the byproduct alcohol usually depends on rectification, so that the energy consumption is higher. Patent CN207371131U describes a reaction condensation rectification apparatus for producing, for solve dimethyl carbonate backward flow and methanol separation provide the scheme, but the device is comparatively complicated because of integrating equipment such as condensation, rectification. Meanwhile, in the process of vaporization and condensation reflux of a large amount of dimethyl carbonate, the energy consumption is increased, and the production cost is further increased. Therefore, in order to improve the reaction efficiency, promote the forward shift of the reaction equilibrium, there is a need for a continuous synthesis method capable of efficiently removing the small molecule by-product alcohol, enhancing the gas-liquid contact, reducing the energy consumption, and realizing efficient use of the catalyst. Disclosure of Invention In order to solve the technical problems, the invention provides a method and a system for efficiently synthesizing diphenyl carbonate. The method breaks thermodynamic equilibrium limitation through reaction-distillation coupling, and the polymetallic vanadium oxide composite catalyst can efficiently inhibit anisole side reaction, so that diphenyl carbonate can be synthesized with high conversion rate and high selectivity. In order to achieve the above purpose, the invention adopts the following technical scheme: A method for synthesizing diphenyl carbonate with high efficiency uses phenol and carbonic ester as raw materials, a multi-metal vanadium-oxygen compound as a catalyst, and the raw materials react in a high-temperature reaction kettle with a mechanical stirring, condensing reflux device and a kettle bottom gas distributor, wherein carbonic ester is continuously injected from the kettle bottom of the high-temperature reaction kettle along with inert carrier gas, unreacted carbonic ester is refluxed through fractional condensation, and byproduct alcohol is discharged along with the inert carrier gas; The carbonic ester is dimethyl carbonate or diethyl carbonate; the catalyst is used in an amount of 0.5-5wt% of the mass of the phenol raw material. The method for efficiently synthesizing diphenyl carbonate comprises the following specific steps: S1, feeding and replacing, namely adding phenol and a catalyst into a high-temperature reaction kettle in advance, opening an inert carrier gas valve, introducing inert carrier gas from a gas distributor, carrying out gas replacement on the high-temperature reaction kettle, and exhausting air; S2, heating, namely starting stirring and heating a high-temperature reaction kettle in an inert carrier gas atmosphere, and heating to 120-180 ℃; s3, continuously feeding and reacting, namely pumping liquid carbonic ester through a metering pump, merging the liquid carbonic ester with inert carrier gas from the bottom, and continuously injecting the liquid carbonic ester into the bottom of a liquid layer of the high-temperature reaction kettle in a bubbling mode through a gas distributor; S4, removing and refluxing a product, namely quickly heating and vaporizing a carbonate gas-liquid mixture injected into the bottom of a liquid layer of the high-temperature reaction kettle under the stirring action, fully contacting carbonate steam and phenol liquid on the surface of a catalyst in the rising process to generate transesterification reaction, and enabling the generated by-product alcohol and unreacted carbonate steam to enter a condensation reflux device together with inert carrier ga