反应详情

In the Drawing, A represents a reactor for conversion of cyclohexanone oxime into ε-caprolactam; B, a neutralizer for partial neutralization of the lactam/sulfuric acid mixture; C, an extraction device for extraction of the lactam from the lactam/ammonium hydrogen sulfate mixture formed in the partial neutralization; D, a neutralizer for complete or partial neutralization of the ammonium hydrogen sulfate; E, an installation for reductive decomposition of the ammonium hydrogen sulfate; and F, a sulfuric acid/oleum plant. Through line 1 cyclohexanone oxime is passed into the rearrangement reactor A, for instance a mixing-reactor provided with a stirrer or a vessel with a mixing-cyclone, to which sulfuric acid or oleum from the sulfuric acid/oleum plant F is supplied via line 2. Via line 3 the mixture flows to the neutralizer B, which is supplied with a solution of ammonium sulfate and ammonium hydrogen sulfate, originating from the ammonium hydrogen sulfate neutralizer D, via line 4; with ammonia via line 5; and with water via line 14. The amount of ammonia, supplied as ammonium sulfate, ammonium hydrogen sulfate and ammonia provides at least an equivalent amount of ammonium to react with one equivalent or sulfuric acid. Of course, it is possible fully or partly to replace the ammonia and the water by ammonia water. The rearrangement mixture neutralized to ammonium hydrogen sulfate flows via line 6 to the extraction device C, to which is passed, via line 7, a solvent for caprolactam, in which sulfuric acid, ammonium sulfate and ammonium hydrogen sulfate are poorly soluble, for instance benzene, toluene, 1,2-dichloroethane, chloroform, 1.1.2.2.-tetrachloroethane, ethyl ether or dibutyl carbinol. Caprolactam, dissolved in the extraction agent, is discharged from the system via line 13 and passed to an installation for recovery of the lactam (not exemplified in the drawing). The aqueous solution of ammonium hydrogen sulfate is discharged via line 9. Part of the ammonium hydrogen sulfate solution discharged via line 8 is conveyed to the decomposition device E via line 10 and decompossed under reductive conditions into a gas mixture principally containing ammonia, sulfur dioxide and water vapor. Via line 11 this gas mixture is led to the neutralizer D, which is supplied via line 9 with the remainder of the aqueous ammonium hydrogen sulfate solution originating from the extraction device C and supplied via line 8. With the aid of the ammonia present in the gas mixture from line 11, ammonium hydrogen sulfate is converted into ammonium sulfate in the neutralizer D. A gas mixture mainly containing sulfur dioxide escapes from the neutralizer D and is led to the sulfuric acid/oleum plate F via line 12. By concentrating, by evaporation, the solution passed to the decomposition device E via line 10, the water content can be maintained at the required level. From neutralizer D, the ammonium sulfate/ammonium hydrogen sulfate solution is conveyed -, after purification, purification being optional, - to neutralizer B via line 4.

1. extractionC, an extraction device for extraction of the lactam from the lactam/ammonium hydrogen sulfate mixture
2. customformed in the partial neutralization