Figure 1. BPA synthesis reaction with phenol-acetone condensation.
Sulfuric acid and hydrochloric acid are used as catalyst for the traditional production method. Besides, ion-exchange resins extensively are used as catalyst in industry. BPA must have minimum 95% purity for the epoxy resin production and 99% and upper purity for the polycarbonate synthesis (Wang et al.,2014; Yadav et al., 1997). Depending on the reaction conditions and catalyst types, many by-products occurs in the process of BPA production. In the literature there are various studies to increase yield and selectivity. These studies gen-erally are catalyst works conducted for the purpose of eliminating disadvantages of the mineral acid usage. The common property of these studies is feeding phenol to acetone molar ratio greater that to stochiometric ratio (from 3:1 to 10:1). The reason is to eliminate the by-products occurring self-condensation of acetone and the others (Yadav et al., 1997). However, operational cost, which includes pumping, heating, distillation, is increased with high phenol feeding in this way. As mentioned above high concentration of acetone in reaction media increases by-products due to self-condensation of acetone and side reactions. The most common by-products formed at the end of the reaction are summarized in Figure 2.