FRIEDEL-CRAFTS ACYLATION ON POROUS DIVINYL BENZENE POLYMER PARTICLES - A REACTION KINETIC PROCESS STUDIED BY MID-INFRARED AND NEAR-INFRAREDSPECTROSCOPY

Porous poly(para-divinylbenzene) and poly(meta-divinylbenzene) particl es were synthesized from para-divinylbenzene and meta-divinylbenzene m onomers with toluene and 2-ethylhexanoic acid as porogens, The residua l vinyl groups in the particles were thereafter reacted with lauroyl c hloride by using the Friedel-Crafts reaction, The conversion of vinyl groups was followed by analyzing polymer particles taken from the reac tion mixture at different time intervals. Infrared spectroscopy in bot h the mid- and near-infrared region was used as the analytical techniq ue. The intensity changes in the overtone absorption at 1628 nm due to the vinyl bonds were used as the basis for the quantification of the reaction. Spectra of the particles in the mid-IR region provide unders tanding of the changes taking place in the polymer matrix during the a cylation reaction, The results indicated that the reaction took place at a faster rate in the polymer particles synthesized from para-DVB mo nomer compared with the poly(meta-DVB) particles, The polymer particle s synthesized with toluene as porogen react faster than the polymer pa rticles prepared with 2-ethylhexanoic acid as the porogen. The analysi s also indicated that the acylation takes place at the early stages of the reaction and the product formed transforms into more stable produ cts at the latter stages. On the basis of the infrared analysis, mecha nisms for the formation of the different products are proposed.