Preparation method of adiponitrile and product thereof

Abstract

The invention relates to a preparation method of adiponitrile. The preparation method comprises the following steps: firstly performing a reaction on adipic acid and ammonia at 155-200 DEG C to produce diammonium adipate, and then dehydrating under a catalytic reaction of phosphoric acid or ammonium phosphate to produce adiponitrile; a product can be further separated in a separation tower. The reaction is performed on the adipic acid and the ammonia gas at the low temperature of 155-200 DEG C to produce H4NOOC(CH2)4COONH4 first, and then high-temperature cyanation is performed, so that the opportunity of producing a by-product and a coke from the adipic acid at high temperature is effectively avoided, not only the yield is increased by 3-5%, but also the operation cycle of a production device is prolonged by 30-60 days, and the production per unit time is increased. Liquid phosphoric acid is used as a catalyst, firstly ammonium salt of the phosphoric acid is produced, and the ammoniumphosphate can be mixed with ammonium salt of the adipic acid very well, so that the catalytic performance is improved better and the selectivity of the adiponitrile is increased by more than 2%.

Description

technical field [0001] The invention belongs to the field of chemical industry, and relates to a preparation method of adiponitrile and a product thereof. Background technique [0002] Adiponitrile (ADN), also known as 1,4‐dicyanobutane, has a molecular formula of NC(CH3)4CN. Addition of adiponitrile and hydrogen can generate hexamethylenediamine, and hexamethylenediamine and adipic acid can be produced under strict material distribution. The lower reaction produces nylon 66 salt. As an important intermediate for the synthesis of nylon 66, adiponitrile is the most important and most valuable industrial application developed by adiponitrile. Research has found that hexamethylenediamine can be used to synthesize 1,6‐hexamethylene diisocyanate (HDI), which is another important use for the development of the downstream product chain of adiponitrile; with the rapid development of science and technology, adiponitrile is used in light industry, electronics and other organic Appli...

AI Technical Summary

Problems solved by technology

Adipic acid will generate by-products such as decarboxylation, decomposition, and coking at high temperatures, which not only affect the unit consumption; adipic acid will also generate coke at high temperatures and affect the operating cycle.

[0005] Patent CN201510185122.7 discloses the method for producing adiponitrile by adipic acid liquid phase method. Its main innovation point is the use of solid phosphoric acid catalyst. Although it can be stirred, the mixing effect is not very good, and its catalytic performance will also be affected.

[0006] Patent CN201210577924.9 discloses a method for producing adiponitrile with adipic acid and the equipment used. Its main innovation point is that "after the neutralization reaction of adipic acid and gaseous ammonia in the nitrilation reactor, continue to Dehydration reaction in the tubes of the nitrilation reactor", although two reactions can be carried out in the nitrilation reactor and when the "reaction temperature is 250‐‐290 ° C", but the molten adipic acid is very easy to Side reactions and cokes occur, which affect the yield and the operating cycle of the device

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