Process for continuously and industrially producing terephthalaldehyde by using micro-channel reactor

Abstract

The invention relates to the technical field of terephthalaldehyde preparation, and specifically relates to a process for continuously and industrially producing terephthalaldehyde by using a micro-channel reactor. The micro-channel reactor comprises a plurality of groups of reaction chips, which are communicated in sequence; each reaction chip comprises an outer panel I, a reaction channel I, a reaction channel II, a reaction channel III and an outer panel II, which are laminated at a time; and the process comprises the following steps: crushing, dosing, synthesis reaction, cooling-crystallization, filter-pressing I, sodium carbonate solution washing, filter-pressing II, secondary water washing, filter-pressing, centrifugal separation, drying, packaging, and storage. The yield of terephthalaldehyde produced by an urotropine method is greatly increased, and due to continuous flow production and the high reaction rate, the production efficiency is also greatly improved.

Description

technical field [0001] The invention relates to the technical field of terephthalaldehyde preparation, and the specific field is a process for continuous industrial production of terephthalaldehyde using a microchannel reactor. Background technique [0002] With the development and application of E R series optical brighteners, the consumption of terephthalaldehyde has been increasing, which has attracted many chemical companies to conduct in-depth research on the manufacturing technology of this product. There are many synthetic methods reported, such as: air oxidation of p-xylene, first halogenation (bromination or chlorination) of p-xylene, then hydrolysis or oxidative hydrolysis; reduction of terephthalic acid (or ester); reduction of terephthaloyl chloride; Reductive hydrolysis of terephthalonitrile; oxidation of terephthalamide; electrolytic oxidation or reduction; addition of carbon monoxide and hydrogen to dibromobenzene under high pressure in the presence of n-tribu...

AI Technical Summary

Problems solved by technology

One is to use dilute nitric acid for oxidative hydrolysis, vanadium pentoxide is used as a catalyst, and the yield is 75.6%. Dilute nitric acid causes serious loss to traditional equipment, and process wastewater contains a large amount of heavy metal ions, which seriously pollutes water bodies; the other The first is to use urotropine and water to replace dilute nitric acid and vanadium pentoxide. This process has less equipment loss, but the product yield is 42.7%.

Due to the use of urotropine as the reactant, it involves the Somley reaction, and the reaction process cannot be accurately controlled in the traditional reactor, so the yield is low.

Images