3.1 | DFT Calculations
The most likely by-products that may occur in the bisphenol a synthesis have been determined from the literature. These byproducts are methicyl oxide, chroman I, chromanII and triphenol compounds. By examining each product and by-product mechanism, possible product, ancestor product and transition states that may occur are modeled. All defined molecules were optimized in DFT / 6-311 ++ G (d, p) method and base set. It has been proven that they are optimized at minimum energy by performing frequency calculations. Optimized structures and relative energies of the calculated mo-lecules are shown in Figure 4, and the relative energy values are listed in Table 1.