Method for continuously rectifying thiophanate-methyl ethyl acetate

Abstract

The invention discloses a method for continuously rectifying thiophanate-methyl ethyl acetate. The method comprises the following steps: firstly, reclaiming ethyl acetate in a material by steam heating into a neutralizing kettle through a condenser, starting to stir, dropwise adding 30% sodium hydroxide to neutralize until the pH is 8-9, standing for 30-60 minutes, and separating moisture; pumping into an ethyl acetate crude product large storage tank, and rectifying in a rectification tower through a pump with a preheater; leading low-boiling-point components, moisture and azeotrope of ethyl acetate and moisture to the tower top, liquefying through the condenser, and automatically separating moisture through a customized moisture separator; returning upper ethyl acetate to the tower top to stay moisture-carrying ethyl acetate at the tower top; staying ethyl acetate and heavy components at the tower bottom, and continuously discharging ethyl acetate and heavy components from the tower bottom to an intermediate tank; and pumping into an evaporation kettle with a pump, opening steam to heat and evaporate qualified ethyl acetate, and receiving into a finished product tank through a condenser. The continuous rectifying method can be used for controlling the moisture of ethyl acetate to be lower than 0.1 percent and has low energy consumption, and the reclaimed ethyl acetate has high quality and can reach over 99 percent.

Description

technical field [0001] The invention relates to the technical field of pesticide synthesis, in particular to a method for continuous rectification of thiophanate-methyl ethyl acetate. Background technique [0002] With the development of organic agriculture and facility agriculture, people pay more and more attention to food safety. How to improve the efficiency of pesticide use, reduce the amount of pesticide use, and then reduce the residue of pesticides in agricultural products is the primary priority of current pesticide technicians. one of the tasks. Water-based preparations are highly valued by society today with strict environmental safety regulations. In recent years, my country's water-based pesticides have developed to a certain extent. [0003] Thiophanate-methyl: Chemical name: 1,2-bis(3-methoxycarbonyl-2-thioureido)benzene, common name in English, Thiophanate-Methyl CA registration number: 23564-05-8, chemical formula: C12H14N4O4S2, Relative molecular mass: 3...

AI Technical Summary

Problems solved by technology

However, these traditional dosage forms all have a common feature: the original drug of thiophanate-methyl, additives, and fillers are ground into powder or paste with a particle size of about 5 to 44 microns by jet mill or sand mill, and then added to water Finally, a suspension is formed, and its active ingredients cannot be dissolved in water. After the suspension is sprayed on the surface of crops through agricultural spraying equipment, due to the large particles of the active substance thiophanate-methyl, the active substance particles are deposited on the unit area of ​​the target. Very little, causing a large amount of active substances to be cleaned up by water and wind, and the utilization rate of pesticides is very low. In order to improve the control effect on plant diseases, the conventional method is to increase the dosage of pesticides, and the result is that the pesticide residues in crops exceed the standard , affecting food safety, and also caused a great waste of pesticides, as well as soil pesticide pollution

[0004] There are a series of problems in the original continuous distillation method of thiophanate-methyl ethyl acetate, and it is necessary to explore a feasible continuous distillation method to solve the problems of high impurities, low purity and low synthesis efficiency

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