抄録
The synthesis of polyvinyl cyanoethyl ether by the reaction of polyvinyl alcohol with acrylonitrile vapour, in the presence of NaOH catalyst was studied, including effects of the pretreat-swelling by catalyst (0-5hrs.), amount of water and catalyst (H20/PVA wt. 0.1-2.5 and NaOH/PVA mol 0.01-0.34), time and temperauture of the reaction (0.5-18hrs. and 25-55°C) and atmospheric pressure in the reaction vessel (5-760mm Hg) on the rate of cyanoethylation. At a relatively higher temperature and catalyst concentration, a strikingly abnormal rate of cyanoethylation was observed. This may be due to the accompanying of the inverse reaction of cyanoethylation and the slight degree of hydrolysis of the cyano group.
Assuming the reaction velocities of the first order for each reaction of the cyanoethylation, decyanoethylation and hydrolysis and the different velocity constants between the crystalline and amorphous regions of polyvinyl alcohol, a theoretical equation for the rate of cyanoethylation is derived. Giving the value of 60% for the accessibility of polyvinyl alcohol and the appropriate values corresponding to the conditions of the reaction for each reaction velocity constant, this equation shows the comparable trend with the experimental results in the principal points.
