Method for preparing N-alkyl-4-nitrophthalimide

Abstract

The invention belongs to the technical field of organic synthetic processes, and relates to a method for preparing N-alkyl-4-nitrophthalimide by adopting N-alkyl phthalimide as a raw material, nitricacid as a nitrating agent, and performing low-temperature nitration reaction by virtue of a continuous flow to prepare the series product of N-alkyl-4-nitrophthalimide. The method is short in reactiontime and short in production period, solves the problems produced by the accumulation of raw materials in an intermittent reaction kettle, is more stable in the reaction process, and can significantly improve the reaction efficiency. The mass transfer performance and heat conduction performance in a micro-channel reactor of different structures can be improved, the constant reaction temperature can be kept, the temperature runaway phenomenon can be avoided, the generation of byproducts can be reduced, and the safety of the reaction process can be improved. By adopting the high mass transfer effect in the micro-channel reactor, a liquid-liquid reaction solution is sufficiently mixed, in the reaction process, the consumption of concentrated sulfuric acid and nitric acid can be greatly reduced, and the generation of waste acid can be reduced.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis technology, and relates to a method for preparing N-alkyl-4-nitro-phthalimide by using N-alkyl phthalimide as raw material and nitric acid as nitrating agent through continuous flow for low-temperature nitration reaction. Method for phthalimide series products. Background technique [0002] Phthalimide is an important fine chemical intermediate, widely used in medicine, pesticide, dyestuff and other fields. With the advancement of science and technology, its new uses have been continuously developed in recent years, and many downstream products have high added value. Disperse dyes have become one of the most active dye categories in the world's dye market. Due to factors such as the industrialization of ultrafine polyester fibers, the growth of polyester fibers for tourism, and the increase in the use of polyester fabrics for sportswear and vehicles, the high Among the high-performance...

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Problems solved by technology

[0004] (1) Using the method of reacting 4-nitrophthalic anhydride with methylamine, the disadvantage is that 4-nitrophthalic anhydride is an uncommon industrial product, and the preparation process is more complicated, with many by-products, it is difficult to achieve the purpose of purification, while 4-nitrophthalic anhydride When reacting with methylamine, the conversion rate of 4-nitrophthalic anhydride is low, resulting in low yield of N-alkyl-4-nitrophthalimide, therefore, this method is not suitable for industrialized production

[0008] At present, the traditional production process of preparing phthalimide azo dye intermediates at home and abroad is mainly based on the process of intermittent nitration with mixed acid, which has the following defects: the heat of nitration reaction is difficult to transfer in time, and it is easy to cause the temperature to run out of control and cause safety accidents; Poor mass transfer efficiency, easy to cause material accumulation, long reaction time

So far, there has been no process research and equipment technology report on the nitration reaction of N-alkylphthalimide in the continuous reaction mode of microchannels

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