Acetic Acid → 4-Cyanobenzaldehyde

500 g of p-cyanobenzylamine crude product (p-cyanobenzylamine 92% by weight, p-xylylenediamine 8% by weight) obtained by hydrogen reduction of terephthalonitrile in the presence of sponge metal nickel catalyst was mixed with 2.5 kg of water while stirring at 40° C. or less and the mixture was stirred for 3 hours. The crystals which precipitated were separated by centrifugation while washing with water to obtain 500 g of p-cyanobenzylamine hydrate (water content: 21% by weight). 500 g of the p-cyanobenzylamine hydrate, 420 g of hexamethylenetetramine, and 2.0 kg of acetic acid were mixed and the internal temperature was elevated to 80° C. while stirring. An aqueous sulfuric acid solution of 300 g of 98% by weight sulfuric acid and 165 g of water was added dropwise thereto over 20 minutes. Further, the reaction mixture was stirred at 100° C. for 1 hour. After the internal temperature was decreased to 50° C., 300 g of 98% by weight sulfuric acid was added. The reaction mixture was concentrated to dryness under reduced pressure. To the concentrated residue was added 900 g of 1% by weight sulfuric acid and stirred vigorously at 100° C. for 3 hours. Thereafter, the reaction mixture was cooled to room temperature for 2 hours. The crystals which precipitated were filtered, washed with water, and dried to obtain 295 g (yield: 75%) of p-cyanobenzaldehyde. The purity was 99.5% or more. Under nitrogen atmosphere, 295 g of the p-cyanobenzaldehyde and 4.5 g of 2,2-azobisisobutyronitrile were mixed. The temperature was elevated to 105° C. and 190 g of chlorine was bubbled over 3 hours with vigorous stirring. After dry nitrogen gas was introduced into the reaction mixture for 1 hour, the solvent was distilled under reduced pressure to obtain 302 g (yield: 81%) of p-cyanobenzoyl chloride. The purity was 98.5%.

1. customwas elevated to 80° C.
2. stirringFurther, the reaction mixture was stirred at 100° C. for 1 hour
3. customwas decreased to 50° C.
4. concentrationThe reaction mixture was concentrated to dryness under reduced pressure
5. additionTo the concentrated residue was added 900 g of 1% by weight sulfuric acid
6. stirringstirred vigorously at 100° C. for 3 hours
7. customThe crystals which precipitated
8. filtrationwere filtered
9. washwashed with water
10. customdried

ORD record

ord-5afa765c709a4ac8a30abf941677c54d

Source dataset

uspto-grants-2001_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06262292B1