Hydroxylamine sulfate is easily soluble in water and practically insoluble in organic solvents. To promote the conversion of CHO, the other reaction product, cyclohexanone, can be removed from the hydrolysis reaction by reactive extraction. The effects of different extraction solvents on the hydrolysis reaction of CHO in sulfuric Z-Lys-OH were investigated and the experimental results were summarized in Table 1. The extraction solvent has a significant impact on the conversion of CHO by breaking the reaction equilibrium. From Table 1, it can be clearly seen that dichloromethane showed an excellent CHO conversion of 50% among these extraction solvents. In contrast to dichloromethane, the increased conversions of CHO were smaller and had no remarkable differences among n-hexane, cyclohexane, benzene and toluene. Unfortunately, dichloromethane with low boiling point (39.8 °C) is very easily volatile, which may cause the loss of cyclohexanone and difficulty for continuous reactive extraction under higher temperature. Therefore, the selection of a suitable solvent in terms of volatilization and extraction efficiency is very important in the hydrolysis reaction of CHO. As a auxiliary solvent in ammoximation process  and , cyclohexane has a higher boiling point (80.7 °C) and good extraction efficiency for cyclohexanone, and monocytes can be conveniently recycled between the hydrolysis of CHO and ammoximation process of cyclohexanone without further treatment. Considering the above factors, cyclohexane can serve as a suitable extraction solvent in the acid-catalyzed hydrolysis reaction of CHO.