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Process for the production of diaryl carbonates and treatment of alkalichloride solutions resulting therefrom

A technology of diaryl carbonate and alkali metal chloride, which is applied in the field of joint process, and can solve the problems of high cost and large amount of energy

Inactive Publication Date: 2008-03-12
BAYER MATERIALSCIENCE AG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It has also been suggested that a highly concentrated sodium chloride solution could be fed to the electrolytic cell by evaporating the sodium chloride-containing solution by heating, however evaporation requires a lot of energy and is expensive

Method used

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  • Process for the production of diaryl carbonates and treatment of alkalichloride solutions resulting therefrom
  • Process for the production of diaryl carbonates and treatment of alkalichloride solutions resulting therefrom
  • Process for the production of diaryl carbonates and treatment of alkalichloride solutions resulting therefrom

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0082] Example 1: Addition of sodium chloride-containing reaction waste water to sodium chloride electrolysis—Addition of 17% (weight) sodium chloride solution from DPC manufacture.

[0083] A mixture of 14.5% (weight) sodium hydroxide solution of 145.2kg / h and 48.3kg / h of phenol with 86.2kg / h of methylene chloride and 27.5kg / h of carbonyl chloride (based on phenol exceeding 8 % (mol))) were mixed together in a vertically placed and cooled tubular reactor, the reaction mixture was cooled to 33° C., and the pH was measured to be 11.5 after an average residence time of 15 seconds. In the second step of the process, 5.4 kg / h of 50% NaOH were subsequently metered into the reaction mixture so that the pH value of the second reaction stage was 8.5 after a further 5 minutes of dwell. In the continuously running reactions, existing metering fluctuations were compensated by adjusting the NaOH added in each case. In the second step of the process, the reaction mixture is continuously m...

Embodiment 2

[0088] Example 2: Addition of reaction waste water containing sodium chloride to sodium chloride electrolysis using a gas diffusion electrode - addition of a 17% by weight sodium chloride solution from DPC manufacture.

[0089] The composition of the waste water is the same as the composition of the waste water obtained according to Example 1. Since hydrogen is not required for the manufacture of DPC, the generation of hydrogen can be omitted during the electrolysis process. Electrolysis is therefore carried out with gas diffusion electrodes. The current density is 4kA / m 2 , the outlet temperature on the cathode side is 88°C, and the outlet temperature on the anode side is 89°C. Electrolyzers with standard anodic coatings from DENORA (Germany) were used. A Nation 982 WX ion exchange membrane from DuPont was used. The electrolytic voltage is 2.11 volts. The sodium chloride concentration of the solution removed from the anode chamber was 17% by weight NaCl. 0.166 kg / h of 1...

Embodiment 3

[0092] Example 3: Addition of sodium chloride-containing reaction waste water to sodium chloride electrolysis with gas diffusion electrodes - addition of 17% by weight sodium chloride solution (reaction waste water) from DPC production.

[0093] The composition of the waste water is the same as the composition of the waste water obtained according to Example 1. Since hydrogen is not required for the manufacture of DPC, the generation of hydrogen can be omitted during the electrolysis process. Therefore electrolysis is carried out with a gas diffusion electrode at a current density of 4kA / m 2, the outlet temperature on the cathode side is 88°C, and the outlet temperature on the anode side is 89°C. An electrolytic cell with standard anodic coating from DENORA (Germany) was used. DuPont's Nation 2030 WX ion exchange membrane was used. The electrolytic voltage is 1.96 volts. The sodium chloride concentration of the solution removed from the anode chamber was 15% by weight NaCl...

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Abstract

Processes comprising: (a) reacting phosgene and a monohydroxyl aryl compound in the presence of a suitable catalyst to form a diaryl carbonate and a solution comprising an alkali chloride; (b) separating the diaryl carbonate from the solution; (c) adjusting the pH of the solution to a value of less than or equal to 8 to form a pH-adjusted solution; (d) treating the pH-adjusted solution with an adsorbent to form a treated solution; (e) subjecting at least a portion of the treated solution to electrochemical oxidation to form chlorine and an alkali hydroxide solution; and (f) recycling at leasta portion of one or both of the chlorine and the alkali hydroxide solution.

Description

technical field [0001] The present invention generally relates to a combined process for the manufacture of diaryl carbonates and the electrolysis of process wastewater containing alkali metal chlorides. The present invention also relates in particular to a method for treating waste liquids containing alkali metal chlorides and for their further use in a diaryl carbonate production process, especially in a diphenyl carbonate production process ("DPC process"). Background technique [0002] The manufacture of diaryl carbonates, especially diphenyl carbonate, is usually carried out in a continuous process by making or introducing phosgene and subsequently allowing phosgene and monohydric phenol to react at the interface in the presence of a base and a nitrogen catalyst in an inert solvent The reaction proceeds according to the following general reaction formula: [0003] [0004] The production of diaryl carbonates, e.g. by interfacial polycondensation, has been reported i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/96C07C68/02C25B1/26C25B3/23C01B32/80
CPCC25B1/34C01D3/04C07C68/02C01D3/06C25B1/46C25B15/08C07C69/96C07C68/00
Inventor A·布兰P·乌姆斯R·韦伯J·雷克纳M·巴茨J·范登艾恩德
Owner BAYER MATERIALSCIENCE AG
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