Adsorption of propylene and allene on TiCl3·1/3 AlCl3 and polymerization of allene with the system TiCl3·1/3 AlCl3/AlEt2Cl

• Published in: Die Makromolekulare Chemie 1987-08, Vol.188 (8), p.1773-1779
• Main Authors: KRATOCHVILA, J, MEJZLIK, J
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Polymerization; Preparation, kinetics, thermodynamics, mechanism and catalysts
• ISSN: 0025-116X; 0025-116X
• DOI: 10.1002/macp.1987.021880801

Adsorption of propylene and allene from the gas phase on TiCl3·1/3 AlCl3 and TiCl3·1/3 AlCl3/AlEt2Cl catalyst was measured volumetrically. In the ranges of 296–334 K and 1–100 kPa, the adsorbed amounts of both gases was found to be approximately proportional to the gas pressure. The adsorbed amount of allene is about twice as high as that of propylene under the same conditions. Low heats of adsorption of both propylene and allene support the assumption of the physical nature of the adsorption. Addition of AlEt2Cl to the TiCl3·1/3 AlCl3 catalyst did not change substantially the sorption properties of the catalyst. Polymerization of allene with the system TiCl3·1/3 AlCl3/AlEt2Cl in heptane was found to be first order in monomer and the rate decreases with increasing yield. A mechanism of retardation by the polymer formed is probably operative. Both heptane‐soluble and heptane‐insoluble polyallenes are produced. The soluble polymer has M̄n ≈ 103 and a very narrow molecular weight distribution (M̄w/M̄n = 1,2 ± 0,2). Polyallene comprises mainly vinylidene units.