Thermal high pressure hydrogenolysis II. The thermal high pressure hydrocracking of fluorene

The thermal hydrocracking of fluorene was investigated in the temperature range of 400 to 480 °C and hydrogen pressures of up to 375 atm. As main reaction products were found 2-methylbiphenyl, biphenyl, toluene and benzene. They account for about 90% of the converted fluorene. Only very low concentrations of diphenylmethane were detected at the highest temperature. This indicates that the opening of the phenyl - CH2 bond in fluorene is much faster than the splitting of the phenyl - phenyl bond. The splitting of the phenyl - phenyl bond in biphenyl, however, proceeded with a rate equal to the splitting of the phenyl - CH2 bond in fluorene and the phenyl - CH3 bond in 2-methylbiphenyl

Mechanism of hydroformylation, part II : Study of the formation of hydrocobalttetracarbonyl by the reaction of Co2(CO)8 and H2

The kinetics and the position of the equilibrium of the reaction Co2(CO)8+H2⇄2 HCo(CO)4 were studied in the range of 80–160 °C and 50–100 atm. by means of in situ IR spectroscopy.\ud \ud The reaction is reversible first order with respect to CO2(CO)8 and HCo(CO)4 and the energies of activation of the forward and the reverse reaction are found to be 17,3 cal/mole, and 11.0 kcal/mole resp.\ud \ud The reaction is slightly endothermic with ΔH=6.6 kcal/mole and ΔS=14.6 e.u. The heat of formation of HCo(CO)4 and the bond strength between hydrogen and cobalt in HCo(CO)4 were found to be—146.1 kcal/mole and 54.7 kcal/mole resp

Study of the mechanism of hydroformylation at industrial reaction conditions

With a newly developed analytical technique, i.e. high temperature/pressure IR cell coupled to the reactor, it was possible to study the mechanism of hydroformylation at reaction conditions. It has been conclusively found that the hydrogenolysis of the acyl cobalt complex is performed by HCo(CO)4 and not by molecular H2, as proposed byHeck andBreslow. Therefore the formation of HCo(CO)4 from Co2(CO)8 is an intermediate step in the sequence of hydroformylation reaction steps. The rate of hydroformylation of any of the olefins is smaller than the rate of formation of HCo(CO)4 from Co2(CO)8. The IR spectra reveal that always more than 30% of the cobalt is in the form of HCo(CO)4 under the reaction conditions. It is found that the formation of HCo(CO)4 from Co2(CO)8 is the slowest and most temperature-dependent step of the hydroformylation reaction. Also the reaction between olefin and HCo(CO)4 is slower than the hydrogenolysis of the acyl complex. The experiments were carried out under industrial oxo conditions. The diffusional effects were eliminated