Method for preparing bromo-2-methylpropane through bromination of tertiary butanol in continuous flow micro-channel reactor

Abstract

The invention discloses a method for preparing bromo-2-methylpropane through bromination of tertiary butanol in a continuous flow micro-channel reactor, belonging to the technical field of organic synthesis application. The method is a new process in which the tertiary butanol and hydrobromic acid are used as raw materials and concentrated sulfuric acid is used as a catalyst to synthesize the bromo-2-methylpropane in the reaction time of scores of seconds to several minutes in the continuous flow micro-channel reactor. Three steams of materials are led into the continuous flow micro-channel reactor through a metering pump and are preheated, mixed and reacted to finally obtain a bromination product, i.e., the bromo-2-methylpropane. The method is easy and convenient to operate, so that high-yield continuous production of the bromo-2-methylpropane becomes possible, and the process has low environment pollution. The conversion rate of the tertiary butanol reaches 78-95 percent, and the selectivity of the bromo-2-methylpropane reaches 92-97 percent.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis application, and in particular relates to a method for preparing brominated tert-butane by bromination of tert-butanol as a raw material, more specifically, in a continuous flow microchannel reactor, using hydrobromic acid to brominate A process for preparing tert-butane bromide from tert-butanol. Background technique [0002] Bromo-tert-butane is an important chemical raw material and an important organic intermediate, which can be used as a solvent and an alkylating agent and intermediate in organic synthesis; it can also be used as a spice (such as methyl amyl ketone ) and the raw materials used to synthesize tert-butylbenzene and p-di-tert-butylbenzene. [0003] At present, the main industrial preparation process is to obtain tert-butanol through bromination reaction. Bromination is generally carried out by hydrobromic acid-concentrated sulfuric acid method or bromide salt-concentr...

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Problems solved by technology

This method produces a large amount of waste acid, which has serious environmental pollution, a large amount of catalyst, and generally low yield of bromo-tert-butane

In addition, metal bromide salts are often used in industry to react with concentrated sulfuric acid and catalyze bromination of tert-butanol to prepare brominated tert-butane. In this method, concentrated sulfuric acid is used as both a catalyst and a reactant, and the reaction is violent and exothermic. It is easy to cause volatilization of raw materials and products, and the consumption of concentrated sulfuric acid is large, the utilization rate is low, and the amount of waste acid produced is large

Since the reaction is carried out in a batch kettle, the reaction time is longer, and the consumption of raw materials is large, and the yield is low, which cannot meet the needs of large-scale industrial production.

[0005] So far, there has been no research on the liquid-phase bromination of tert-butanol to synthesize tert-butane bromide in a microchannel continuous flow mode. Process route, the advantage of this process route is that the temperature of the reaction, the molar ratio of the raw material and the catalyst and the residence time of the reaction, etc. are precisely controlled, and the bromination product tertiary bromide can be obtained in a higher yield within tens of seconds to several minutes. butane

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