Study On ZnC_l2Modified Ion Exchange Resin Catalyzed Condensation Of Phenol With Acetone

Bisphenol-A (BPA) is an important organic chemical material, mainly used forthe production of epoxy resin and polycarbonate. Catalyst plays an important role inBPA synthesis, it is necessary to find out high efficient and environmental protectiontechnology. In this article, we prepared ZnCl2modified acid resin catalyst, thencharacterized and studied technology conditions of BPA synthesis.Firstly, an ion-exchange method was used to prepare a series of Lewis acidmodified ion exchange resin catalyst. The results showed that ZnCl2modified acidresin catalyst gave best catalytic properties. This can be attributed to the acid strengthof Lewis acid, Lewis acid with weak strength can combine with sulfonic acid groupsto form new acid sites. The optimal preparation conditions for ZnCl2modified strongacid resin catalyst were studied. When the concentration of ZnCl2is2%, exchangetime is6h, dry time is48h and absolute ethyl alcohol as solvent, we obtainedZnCl2-modified ion exchange resin catalyst with1.2mmol/g content of zinc ion andexchange capacity is6.7mmol/g. This catalyst shows best catalytic performances inBPA synthesis.Secondly, ZnCl2-modified ion exchange resin catalysts were characterized byscanning electron microscope (SEM), fourier transform infrared spectroscopy (FT-IR),pyridine adsorption and thermogravimetry (TG-DTG). SEM results show that themodified ion exchange resin has less cracks and still has a majority of macropores,FT-IR states that the basic skeleton of the original resin and modified resin unchanged,S=O in modified resin becomes unequal; pyridine adsorption showed that there existsLewis acid sites and Br nsted acid sites in ZnCl2-modified resin catalyst but onlyBr nsted acid sites in ion exchange resin; TG-DTG curves showed that the stability ofZnCl2-modified resin catalyst was enhanced.Finally, we use ZnCl2-modified ion exchange resin as catalyst and studied thereaction conditions. The results showed that the optimal reaction conditions were: theamount of catalyst was13%, mole ratio of phenol to acetone was8:1, stirring rate was800rpm, reaction temperature was70oC and reaction time was60min. Under theabove conditions, BPA yield was70%and selectivity was95%. Recycle of catalyst was also studied, BPA yield remains above67%and BPA selectivity was92%afterthe catalyst was used for five times. The content of product was tested by HPLC.