Tail gas hazard-free treatment method in synthesis of carbamate pesticide

Abstract

The invention relates to a tail gas hazard-free treatment method in the synthesis of a carbamate pesticide. The method comprises the following steps: (1) firstly adding o-sec-butylphenol and triethylamine into a reaction kettle in a volume ratio of 1 to 0.005; (2) then introducing tail gas which comprises methyl isocyanate and is generated in the synthesis process of the carbamate pesticide, controlling the temperature of the reaction kettle between 30 and 50 DEG C and reacting for 1 to 3 hours; (3) detecting the content of BPMC in the reaction kettle after the reaction and stopping introducing the air when the content of BPMC is up to 40 to 50 percent and dropwise adding high-purity methyl isocyanate, wherein a volume ratio of the high-purity methyl isocyanate to the o-sec-butylphenol is 0.19-0.27:1; (4) then dropwise adding high-purity methyl isocyanate in the reaction kettle under the condition that the temperature of the reaction kettle is between 30 and 50 DEG C and preserving the heat for 15 to 60 minutes; and (5) finally detecting the content of BPMC which is subjected to the processing of the steps in the reaction kettle until the content of BPMC is over 95 percent. The method has low energy consumption of the process, high utilization and no pollution, ensures that the isocyanate resource is utilized and fulfills the aim of energy conservation and emission reduction.

Description

technical field [0001] The invention relates to the fields of environmental protection and resource recycling, and particularly proposes a method for harmless treatment of tail gas in the synthesis of carbamate pesticides, which not only solves the problem of tail gas pollution to the environment, but also makes use of isocyanate resources in the tail gas. Background technique [0002] Carbamate pesticides are a class of pesticides that appeared after organophosphates, and mainly include carbofuran, aldicarb, methomyl, propoxur, secbucarb, methiocarb, etc. Since the 1970s, due to the prohibition or restriction of organochlorine pesticides and the increasing number of insect species resistant to organophosphate insecticides, the amount of carbamate pesticides has increased year by year. At present, the industrial production of carbamate pesticides is mainly based on the isocyanate process route. In order to improve the conversion rate of organic intermediates in the synthesi...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to improve and innovate the shortcomings and problems existing in the background technology, to provide a high conversion rate, no pollution in the whole recycling process, and to completely solve the pollution of isocyanate to the environment and the utilization of isocyanate resources. Method for the harmless treatment of tail gas in the synthesis of carbamate pesticides