Caprolactam
| 원료 | cyclohexane; Ammonia |
| 생산물 | caprolactam |
| 적용 | To produce caprolactam from cyclohexane and ammonia using a "photonitrozation" (PNC) process. |
| 설명 | Description: Ammonia is catalytically oxidized (1) with air to form nitrogen oxides, which are reacted (2) with sulfuric acid to form nitrosyl sulfuric acid. Hydrogen chloride gas is introduced into the acid at the nitrosyl chloride generator (3) where a gas mixture of nitrosyl chloride and hydrogen chloride is produced. The gas mixture is introduced into liquid cyclohexane in the photochemical reaction vessel (4). The photonitrozation of cyclohexane to cylohexanine oxime hydrochloride takes place in this vesse with actinic light emiltted by mercury lamps. Unreacted nitrosyl chloride is removed from the reaction vessel. then recirculated to photochemical reaction. Oxime separates (5) from the cyclohexane as a heavy oil and passes on to the Beckmann rearrangement (6). Unreacted cyclohexane is recycled to the photochemical reactor (4). Cyclohexanone oxime hydrochloride is treated with oleum to produce a solution of caprolactam in sufuric acid by Beckmann rearrangement (6). Hydrogen chloride, which evolves during the rearrangement reaction, is recycled to nitrosyl chloride manufacture (3). The solution of the crude caprolactam in sulfuric acid, after Beckmann rearrangement, is neutralized (7) with ammonia. The mixture separates (8) into two layers: the upper layer consists of crude caprolactam and the lower layer of aqueous ammoniunm sulfate solution. Next, the caprolactam is processed through purification stages including chemical treatment and distillation (9). The ammonium sulfate solution is crystallized (10) to produce fertilizergrade ammonium sulfate crystals. |