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The kinetics of the low-pressure synthesis of methanol from carbon monoxide and hydrogen and of the reverse shift reaction of carbon dioxide over a commercial Cu/Zn0/Al203 catalyst are studied. The investigation is performed under typical commercial conditions with a Berty CSTR reactor. Reliable kinetic models which conveniently describe the results are derived for the two reactions. The analysis of the data is carried out considering the outlet mole fractions as the variables subject to experimental error.

S U M M A R Y :Polymerizations of propylene to syndiotactic polymer have been carried out in the presence of the catalyst system VC14-Al(CzH5)2Cl-anisole. The data obtained have been related to those previously reported concerning the catalyst system, VC14-Al(CzH&Cl.It was thus possible to propose a mechanism of formation of the catalytic complexes and to put forward or confirm some hypotheses on their constitution.A polymerization mechanism is also proposed that can justify both the type of stereoregularity of the polymer and the variation of steric regularity on varying the polymerization conditions. Z U S A M M E N F A S S U N G :Propylen wurde mit dem Katalysatorsystem VC14-Al(C2H&Cl-Anisol zu syndiotaktischem Polypropylen polymerisiert. Die Ergebnisse werden mit friiheren Versuchen verglichen, bei denen das biniire System V C~~-A~( C~H~) Z C~ verwendet wurde. Aus den erhaltenen Daten konnten ein Bildungsmechanismus und die mutmal3liche Struktur des katalytisch wirksamen Komplexes abgeleitet werden. Ferner wird ein Polymerisationsmechanismus vorgeschlagen, der sowohl den Typ der Stereoregularitat als auch deren hinderung mit wechselnden Polymerisationsbedingungen erklart. * ) As in general the polymerization rate is not constant with time, we shall refer to the average polymerization rate observed in each run.