高温液态水中2,6-二氟苯腈水解反应动力学

为了开发2,6-二氟苯甲酰胺的绿色制备工艺以及探讨高温液态水中腈类物质的水解规律,研究了高温液态水中2,6-二氟苯睛无催化水解反应动力学.系统地研究了不同初始浓度、不同温度下2,6-二氟苯腈、2,6-二氟苯甲酰胺的水解反应动力学以及2,6-二氟苯甲酸的脱羧反应动力学.采用一级串联反应动力学方程拟合2,6-二氟苯腈的水解...

Kinetics of 2,6-difluorobenzonitrile hydrolysis in high temperature liquid water

2,6-Difluorobenzamide is an important organic reaction intermediate that is mainly used for synthesizing fluor-benzylacylurea class pesticide intermediate. One of the methods for 2,6-difluorobenzamide preparation is inorganic acid/base catalyzed hydrolysis of 2,6-difluorobenzonitrile,which causes serious waste water pollution. A green preparation technology of non-catalytic hydrolysis of 2,6-difluorobenzonitrile to 2,6-difluorobenzamide in high temperature liquid water was studied in this work. 2,6-Difluorobenzonitrile hydrolysis is typical consecutive reactions with 2,6-difluorobenzamide and 2,6-difluorobenzoic acid as intermediates and m -difluorobenzene as the final product. The hydrolysis kinetics of 2,6-difluorobenzonitrile and 2,6-difluorobenzamide,decarboxylation kinetics of 2,6-difluorobenzoic acid were determined at different initial concentrations and temperatures. With consecutive first-order kinetics models,the apparent activation energies evaluated were 96.7 kJ·mol^-1 for 2,6-difluorobenzonitrile hydrolysis and 75.4 kJ·mol^-1 for 2,6-difluorobenzamide hydrolysis,and 184.3 kJ·mol^-1 for 2,6-difluorobenzoic acid decarboxylation. A yield of 64.27% of 2,6-difluorobenzamide could be reached at 523.15 K and reaction time of 300 min,which proved the technical feasibility of non-catalytic hydrolysis of 2,6-difluorobenzonitrile to 2,6-difluorobenzamide in high temperature liquid water. The results could provide important basic data for the green preparation of 2,6-difluorobenzamide as well as the study of hydrolysis of nitriles in high temperature liquid water.