Certain characteristics of the polymerization of butadiene‐1,3 in presence of soluble cobalt complex catalyst

Abstract

Studies were carried out on the kinetics of the process for producing 1,4‐cis‐polybutadiene in the presence of the catalytic system formed of monochlordiisobutylaluminum and the alcoholic complex of cobalt chloride. The experiments, carried out in homogenneous benzene solution at room temperature, pointed out the predominant role of water: when water is absent butadiene forms oligomers. Under the given conditions, the rate of polymerization of butadiene increases with the increase in the concentration of cobalt or aluminum compound and varies in a strange way when the water concentration changes. The dependence of the rate of polymerization on water concentration accounts for the difficulties in the reproductibility of experiments. The molecular weights of the polymers obtained increase linearly with the increase in water concentration and decrease with the decrease in the concentration of aluminum or cobalt compound. No dependence was noticed between the microstructure of polymers and the conditions of working.

Active‐center equilibrium in Ziegler–Natta butadiene polymerization

“…The curved section of these plots, between Al/Co ratios of 25 and 200, appears to represent a rate order of a half, with respect to the aluminum alkyl concentration. This misrepresentation is probably the reason why some researchers claim such a dependence 22, 23. Conversely, measurement of the cocatalyst rate order at high Al/Co ratios will give a rate order of zero 20, 24.…”

Structure du composé CoCl2.2,5C2H5OH et classification de composés d'addition de métaux divalents

“…2,5C2HsOH se rattache ~t une ,~tude plus large effectu6e ~ la fois par des m&hodes physicochimiques (raise en 6vidence et identification des compos6s, thermolyse, mesure des pressions de d6composition) et radiocristallographiques sur l'association avec les alcools, des halog6nures du type MX2; M appartenant ~ la s6rie de m&aux bivalents Mn, Fe, Co, Ni, Cd, X &ant C1, Br ou I. Certains de ces compos6s, en particulier CoCI2.2,5CEHsOH sont utilis6s comme catalyseurs dans la chimie des 61asto-m6res (Diaconescu & Medvedev, 1965). Ces compos6s sont extr6mement instables ce qui rend leur &ude tr6s d61icate: ils sont hygroscopiques et passent facilement l'&at d'hydrates; ils sont d61iquescents dans une atmosph6re humide d'alcool, et ils perdent facilement l'alcool sous forme de vapeur, dans une atmosphere dont la pression partielle en alcool est inf6rieure ~ la pression de d6composition du compos6.…”