Abstract:

Friedel-Crafts acylation reaction of crosslinked polystyrene(CPS) microspheres was conducted in the precence of a Lewis acid catalyst at room temperature using two kinds of ω-chloroacyl chloride, chloroacetyl chloride and chlorobutyryl chloride, and chloroacylation crosslinked polystyrene(CACPS) microspheres were prepared. The chemical structure and composition of the resultant microspheres were characterized and determined by means of infrerad spectroscopy and Volhard methods. The effects of various factors on the chloroacylation reaction were investigated. The experimental results show that the chloroacylation process is always accompanied by Friedel-Crafts alkylation reaction, which is a side reaction leading to additional crosslinking. This side reaction not only decreases the content of the chloroacyl groups on CACPS microspheres, but also makes the property of the microspheres poor. An optimal equilibrium point, at which the chlorine content of CACPS microspheres is the highest, between acylation reaction and alkylation crosslinking reaction can be reached under the following conditions: room temperature, CHCl3 as the solvent, SnCl4 as the catalyst, a 1.2∶1 molar ratio of catalyst to chain unit of polystyrene of CPS, 10 mL used solvent per 1 g CPS microspheres. The result still indicates that the chloroacylation via chlorobutyryl chloride is better than that via chloroacetyl chloride.

Key words: polystyrene microspheres,chloroacetyl chloride,Friedel-Crafts acetylation reaction,Friedel-Crafts alkylation reaction,additional crosslinking