アミン類を主剤とする防食剤の研究 (第14報)

腐食抑制剤と触媒毒-その1

抄録

If a dilute solution of a corrosion-inhibitor is allowed to remain in contact with a limited amount of catalyst, such as nickel hydrogenation catalyst, the catalyst will be adsorbed on the surface by the inhibitor. The catalyst loses its activity by being shielded with the inhibitor film.
The partial catalytic hydrogenation of crotonaldehyde in an autoclave proceeds as follows:
(1) CH₃CH=CHCHO H₂→CH₃CH₂CH₂CHO
(2) CH₃CH=CHCHO H₂→CH₃CH=CHCH₂OH
The former reaction is taken place mainly at lower temperature and the latter at higher temperature. With non-shielded nickel catalyst the reaction proceeds at about 40°C and the partially hydrogenated product is almost butyraldehyde which identifies that the reaction proceeds only as shown in the equation (1). With C₁₆H₃₃NH₂-treated catalyst the reaction proceeds at about 80°C and the product contains crotylalcohol which identifies the equation (2). With C₁₅H₃₁CONH₂-treated catalyst the reaction proceeds at 130°C and crotylalcohol is predominant.
So, the inhibitor film chemi-sorbed onto the metal surface will leave from there at definite temperature, as given by type of functional group. The treated catalyst revives at the critical temperature of the desorption and the catalytic reaction can proceed as contact with non-treated catalyst.