Continuous preparation method of chloroformate

Abstract

The invention belongs to the technical field of chloroformate synthesis, and particularly relates to a continuous preparation method of chloroformate. The preparation method comprises the following steps: 1) feeding reactant raw material alcohol and phosgene into a synthesis tower through an absorption tower, and reacting to generate a crude product chloroformate and a byproduct hydrogen chloride; (2) feeding the crude product chloroformate formed in step (1) into a degassing tower, returning phosgene removed from the degassing tower into the synthesis tower, performing continuous reaction, and rectifying the chloroformate subjected to phosgene removal in a refining system to obtain the target product chloroformate; and 3) feeding a byproduct hydrogen chloride formed in step 1) into an absorption tower, washing with raw material alcohol, and feeding into a tail gas system. The method has the beneficial effects that synthesis and deacidification continuous production of the chloroformate product are realized, the synthesis reaction speed is increased, and the deacidification time is shortened; and meanwhile, phosgene is recycled, so that the consumption of the raw material is reduced, and clean and intrinsically safe automatic production is formed.

Description

technical field [0001] The invention belongs to the technical field of chloroformate synthesis, in particular to a continuous preparation method of chloroformate. Background technique [0002] At present, the most extensive chloroformate process technologies include: batch method, semi-continuous method, the synthesis and deacidification of chloroformate products take a long time, the production of continuous synthesis and continuous deacidification has not been realized, and the degree of automation is not high, and the consumption of raw materials high cost. [0003] The batch method is mainly to add a certain amount of alcohol and phosgene to the synthesis tank for reaction. After the reaction, the material is sent to the deacidification tank for nitrogen deacidification until the product reaches the target; the single tank reaction time is 24 hours, and the deacidification time is also At about 24 hours, the single-pot production efficiency is low and the reaction selec...

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Problems solved by technology

[0007] 1. The single-pot reaction time is about 24 hours, the reaction speed is slow, and the reaction selectivity is low

[0008] 2. The deacidification time is about 24 hours, and the single-pot production efficiency is low

[0009] 3. In order to increase production capacity, a large number of deacidification kettles need to be arranged, and the investment in fixed assets is high

[0010] 4. A large amount of nitrogen gas is required for deacidification, which leads to high energy consumption and high cost of waste gas treatment

[0011] 5. Most operations require manual on-site switching operations, which is low in automation, labor-intensive and not conducive to occupational health

[0012] 6. The raw material of phosgene needs a large excess, the consumption of phosgene is high, and the cost of waste gas treatment is high

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