On The Carbonyl Production Using Low-Pressure Liquid Cycling

This paper first summarizes the development and principle of carbonylation synthesis at low pressure. Combined with the operation status of the equipment of butyl alcohol and 2-ethyl hexanol in the second fertilizer factory of Qilu company, wherein the catalyst was replaced in 2004, the major factors which influenced the reaction of the carbonylation were investigated. Such factors included the influence of temperature on the reaction rate of butyraldehyde and selective of propylene, the influence of partial pressure of propylene, hydrogen and carbon monoxide on the carbonylation synthesis, the influences of rhodium concentration on the formation rate of aldehyde, the selectivity of propylene, N/I ratio, the influence of the ligand triphenyl phosphine of rhodium catalyst on the formation rate of aldehyde, the selectivity of propylene and N/I ratio, and the activity of rhodium catalyst with time were disscussed. The activity of rhodium catalyst, which was an important aspect of process control, was investigated in detail based on an incident of rhodium catalyst deactivation in 2000. The cause of the incident and the adopted measures were discussed. The major parameters of carbonylation synthesis during the production were concluded, including the ratio of hydrogen and carbon in synthetic gas, the concentration of propylene, the reaction temperature, the addition of new catalyst, et al. The catalytic efficiency of rhodium catalyst was enhanced. Finally, the carbonylation synthesis on further research and engineering application was prospected.