Method for continuously synthesizing 3,3-dimethyl-4-pentenoic acid methylester

Abstract

The invention discloses a method for continuously synthesizing 3,3-dimethyl-4-pentenoic acid methylester and relates to a compound synthesizing technology. Methyl-2-buten-1-ol and trimethyl orthoacetate are taken as raw materials, phenol is taken as a reaction catalyst, and the method comprises the following process steps of: (A) dispensing: continuously adding the trimethyl orthoacetate, the methyl-2-buten-1-ol and the catalyst phenol into a dispensing kettle, and uniformly mixing; (B) synthesizing and separating: continuously conveying the material in the dispensing kettle to a synthesis and separation tower for reaction, continuously separating out the generated byproduct methanol and excessive trimethyl orthoacetate on the top of the tower, and continuously extracting residue at the bottom of the tower; (C) distilling at reduced pressure: continuously injecting the residue of the synthesis and separation tower into a rectifying still, distilling at reduced pressure, and separating out the finished product 3,3-dimethyl-4-pentenoic acid methylester; and (D) storing: conveying the finished product 3,3-dimethyl-4-pentenoic acid methylester to a storage tank, and standing for later use. By the method, the synthetic yield of the 3,3-dimethyl-4-pentenoic acid methylester is improved, and full continuous operation of the process for synthesizing the finished product 3,3-dimethyl-4-pentenoic acid methylester is realized.

Description

technical field [0001] The present invention relates to a kind of synthesis method of compound, in particular to a kind of continuous synthesis method of methyl pyribinate. Background technique [0002] Methyl permethrin is a colorless transparent liquid. It is an important intermediate for the synthesis of DV-methyl chrysanthemum and 2-cis-triflumethrin. Its structural formula is as follows: [0003] [0004] At present, the commonly used synthetic method of methyl pyribinate is to prepare by reacting isopentenol and trimethyl orthoacetate in the presence of a catalyst, and generate by-product methanol simultaneously. The prior art mainly adopts a batch synthesis process. [0005] Chinese patent CN102001940A provides a continuous synthesis method of methyl benzinate, which is to continuously enter trimethyl orthoacetate, catalyst and prenyl alcohol into a tank reactor for 5-60 minutes of mixed reaction to generate bentinate Synthetic feed liquid of methyl pertinate; the...

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Problems solved by technology

There are following problems in this method: first what this method uses is phosphoric acid catalyst, and acidity is stronger, has certain corrosivity to equipment, and reaction rate is lower, and reaction time is longer, and by-product content is higher simultaneously, causes product yield to be relatively low. Low, generally around 88%; Secondly, because the method first reacts, the reaction time needs a residence time of 5-60 minutes, and then the product and impurities are separated, so the full continuous process of the process has not been realized, and the reaction cycle is still relatively longer

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