Studies on polymerizations initiated by syncatalytic systems based on aluminium organic compounds, 2. The interactions of the reactants in the absence of polymerization

Abstract

In the course of studies on polymerizations of isobutene (1) by syncatalysts consisting of ethylaluminium halides and halogens, it became necessary to study the separate reactions between the components of the reaction mixtures. The results showed: a) that in general alkyl chlorides d o not react with halogens in the dark at -35°C and below, but do react in the light; b) that at low temperatures 1 and its dimers react with chlorine more easily by substitution than by addition; c) that ethylaluminium halides react with halogens by forming aluminium halides, ethyl halides and ethylene.The findings of the present study enabled us to design polymerization conditions and procedures which minimize undesirable side-reactions in the polymerization of 1 with syncatalysts.The experiments with the dimer of 1 (i.e. 2,4,4-trimethyl-l-pentene), which is a nonpolymerizable model compound for I, supported our view that initiation occurs by a halonium ion. ZUSAMMENFASSUNG:Im Verlauf von Untersuchungen der Polymerisation von Isobuten (1) durch Synkatalysatoren aus Athylaluminiumhalogeniden und Halogenen, wurde eine Untersuchung der einzelnen Reaktionen zwischen den Komponenten der Reaktionsgemische notwendig. Die Ergebnisse zeigten: a) daB Alkylchloride mit Halogenen im Dunkeln bei -35°C und darunter nicht reagieren. Die Reaktion findet jedoch im Licht statt; b) daR bei niedrigen Temperaturen 1 und seine Dimeren mit Chlor leichter Substitutions-als Additions-Reaktionen unterliegen; c) dal3 Athylaluminiumhalogenide mit Halogenen unter Bildung von Aluminiumhalogeniden, Athylhalogeniden und Athylen reagieren. *I Part 1 : cf.? 2289 A. Priola, S. Cesca, G. Ferraris, and M. di Maina Die Ergebnisse der vorliegenden Untersuchung ermoglichten Polymerisationsbedingungen und -verfahren zu bestimmen, die unerwunschte Nebenreaktionen bei der Polymerisation von 1 mit Synkatalysatoren auf ein Mindestmal3 verringern. Die Versuche mit Dimerem von 1 (2.B. 2,4,4-Trimethyl-l -penten), das eine unpolymerisierbare Modellverbindung fur 1 darstellt, bestatigen unsere Annahme, dal3 die Initiierung durch ein Haloniumion stattfindet.

Modeling of polymerization reactions. I. The cationic polymerization of isobutylene by aluminum organic compounds

“…By the use of eqs. (12) and (13) in a dimensionless form, a set of ordinary differential equations has been obtained and integrated with the Runge-Kutta method (at variable step) using a computer program in CSMP 111. This system of differential equations has been integrated with the following initial conditions: A0 = 0, A1 = 0, €0 = 1, €1 = 1, €2 = 0 By integrating these equations the following information is obtained: the conversion-time curve, the variation with reaction time of the following entities, the concentration of the components of the catalytic system, the rate of polymerization, the number of both dead and living polymer chains, the number and weight average molecular weight, the polydispersity, and finally, by a successive data elaboration, the molecular weight distribution.…”

Block Copolymers between Styrene and Isobutylene by a Direct Route

“…Since the polymerization procedure consists of the addition of chlorine to a quiescent mixture of monomer and Et 2 A1Cl in CH 3 Cl, it can be safely assumed that the monomer-Et 2 A1Cl complex involved in the first step of eq 2 has already reached 560 the equilibrium concentration according to eq 3 when the polymerization is started.…”