A thermochemical study of 2,2'-bis(di-p-toluenephosphino)-1,1'-binaphthyl

A thermochemical study of 2,2'-bis(di-p-toluenephosphino)-1, 1'-binaphthyl(Tol-p-BINAP) has been performed using adiabatic calorimetry, differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). The low-temperature heat capacity of Tol-p-BINAP was determined precisely with a small sample automated adiabatic calorimeter in the temperature range from 80 to 350 K. No indication of any phase transition or thermal anomaly was observed in this temperature region. The high-temperature heat capacity of Tol-p-BINAP was measured with a differential scanning calorimeter in the temperature range from 310 to 660 K. From the DSC curve obtained for this compound, a solid-liquid transition was found at 528.29 K and the enthalpy and entropy of transition were evaluated as 41.98 kJ mol(-1) and 79.47 JK(-1) mol(-1), respectively. The TG analysis of Tol-p-BINAP was carried out in the temperature range from 300 to 850 K, from which it was found that this compound starts to decompose at 662.13 K and transforms completely to naphthalene at 716.22 K in a single step. (C) 1997 Elsevier Science B.V.