carbon monoxide; triphenyl-phosphine oxide in benzene-d6 Kinetics; High Pressure; in C6D6 at 45°C, initial concn. ranges were 3.8E-3 to 2.4E-2 M p-MeOC6H4CH2Mn(CO)5, 3.3E-2 to 0.16 M HMn(CO)4(PMe2Ph) (typically 10-fold excess), 0.040 to 0.30 M OPPh3, and 1.1 to 2.3 atm (8.1E-3 to 1.7E-2 M) of CO; followed by NMR and FTIR;