Study On Preparation Of N - Hexanoic Acid And Catalyst Cu - Sub 2 O / MgO By Dehydrogenation

N-hexanal is widely applied in areas such as resin, medicine, spices. It is the high added value by n-hexanol preparing n-hexanal. Dehydrogenation preparation of hexanal has the advantages of simple operation, less side reaction, environmental security. Therefore, developing the higly efficiency, low price, stability catalysts was the key in the study.This paper have used two kinds of reductants for preparation active Cu2O, and Cu2O/MgO catalyst was prepared by impregnation method. The influence of the process conditions for synthesis of hexanal was studied, and the catalyst was modified by transition mentals. The content of this article is divided into four parts.The first part, Using strong hydrazine hydrate as the reductant for the preparation of active CU2O. The influence of the process conditions for preparation of Cu2O/MgO was studied, and the catalytic dehydrogenation of synthetic process conditions was investigated. The active CU2O preparation conditions are:normal temperature and pressure, n(N2H4): n(NaOH):n(Cu(NO3)2)= 1:2.2:1. The optimal catalyst preparation conditions are:12 h of room temperature impregnation, under the protection of nitrogen drying of 6 h, CU2O load of 26.35%. The experimental results showed that under the conditions of nitrogen flow rate 40 mL min-1, reaction temperature 270 ℃, space velocity 1.25 mL-h-1·g-1, catalyst dosage 12 g, n-hexanol conversion and the selectivity to n-hexanal reached 58.89% and 91.26%, respectively. However, the active Cu2O is easily oxidized in the air, because of Cu2O grain is not complete and existence of oxygen vacancies.The second part, using mild glucose as the reductant for the preparation of active Cu2O, The influence of the process conditions for preparation of Cu2O/MgO was studied, and the performance of the catalyst was evaluated. The active Cu2O preparation conditions are: normal pressure and temperature 60 ℃, reduction time 2 h, n(C6H12O6):n(NaOH): n(Cu(NO3)2)=2:2.6:1. The Catalyst preparation conditions with the first part. The experimental results showed that under the conditions of nitrogen flow rate 40 ml min-1, reaction temperature 290 ℃, space velocity 1.25 mL·h-1·g-1, catalyst dosage 12 g, n-hexanol conversion and the selectivity to n-hexanal reached 72.69% and 91.05% , respectively. Preparation of Cu2O/MgO catalyst using glucose as the reductant is stable in air, and catalytic activity is better than that of hydrazine hydrate as reductant.The third part, using glucose as the reductant for the preparation of Cu2O/MgO catalyst was modified by transition mentals:Fe, Zr, Co, Zn, Mn and Ni. The results showed that the modified with Mn is good additive among transition, n-hexanol conversion and the selectivity to n-hexanal reached 79.36% and 93.79%, respectively.In the last, n-hexanol dehydrogenation reaction kinetics was studied and reaction kinetics equation was deduced. Then we calculated the activation energy is 87.67 kJ-mol-1。...