O-chlorobenzoic acid synthesis process

Abstract

The invention discloses an o-chlorobenzoic acid synthesis process. The innovation point is that the process adopts o-chlorotoluene as a raw material and acetic acid as a solvent and comprises the following steps: heating to 134-136 DEG C under the effect of the composite catalysts cobalt acetate, manganese acetate and sodium bromide; filling oxygen for reaction, wherein the reaction temperature is 135-145 DEG C, the reaction pressure is 1.0MPa, and the reaction time is 5.5-6.5 hours; and after the reaction, cooling, discharging, cooling, filtering and washing to obtain the target product o-chlorobenzoic acid. The synthesis process disclosed by the invention gives overall consideration to the factors such as raw material cost, production flow, production cost and environmental pollution, and has the advantages of high yield, low cost, short flow, no water pollution and the like.

Description

technical field [0001] The invention relates to a synthesis process of o-chlorobenzoic acid, in particular to a synthesis process of o-chlorobenzoic acid with high yield, low cost, short flow and no water pollution, and belongs to the technical field of compound synthesis. Background technique [0002] The molecular weight of o-chlorobenzoic acid is 156.57, colorless acicular or monoclinic crystal, melting point 142°C, easy to sublimate when heated, relative density 1.544, soluble in alcohol and ether, soluble in 900 parts of cold water, more soluble in hot water, insoluble in toluene. O-chlorobenzoic acid is an important fine organic chemical product, an important organic synthesis intermediate and analytical reagent in the fields of dyes, pesticides, medicines, etc. Drugs such as azoles are standard reagents for alkali and iodometric methods, and are used as adhesives, paint preservatives, synthetic dyes, and color films. [0003] According to reports, o-chlorobenzoic ac...

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Problems solved by technology

[0004] The photochlorination method has the advantages of short process flow, easy control of the reaction, easy-to-obtain raw materials, and high reaction yield, but its production cost is high, the equipment is seriously corroded, and a large amount of waste liquid and gas are generated, causing environmental pollution; the reaction conditions of the chemical chlorination method Relatively mild, easy to operate, and mature methods, but the price of chemical oxidants is relatively high. Although the reduction products of some oxidants can be recycled, there are still problems in the treatment of waste water and waste residues; Generally, acetic acid is used as a solvent, and the amount of solvent used is large, so the utilization rate of equipment is low, a large amount of acetic acid needs to be recycled, and acetic acid is highly corrosive, which puts forward high requirements for anticorrosion of reaction equipment and acetic acid recovery equipment. To ensure that acetic acid exists in liquid phase at a higher reaction temperature, pressurized operation is required; the air oxidation method has cheap oxidant, low cost, and good reaction selectivity, but the reaction is carried out at a lower temperature, with weak oxidation ability and low conversion rate. The post-processing operation is complicated, the reaction solution is corrosive, and the equipment needs to use excellent corrosion-resistant materials. Generally, pressurized operation is required to increase the solubility of oxygen, thereby increasing the reaction speed.