Yu.A. Sangalov

Calculation and simulation of the polymerization of isobutylene as a fast reaction

A mathematical analysis of the kinetics of the rapid polymerization of isobutylene has been made; this has been done with a continuous scheme in which the special features of the properties of the reaction medium and the technological parameters of the reaction behaviour are taken into account. It has been shown that rapid reaction with local introduction of the catalyst occur in separate zones as a “flame” with different temperatures and kinetic parameters: this is accompanied by the formation of a polymer with enhanced molecular non-uniformity. The calculated data have been compared with experimental data and they have been found to agree.

Rapid method for determining molecular characteristics of polyisobutylene

Abstract Results are given of determining molecular characteristics of polyisobutylene using a combination of a liquid chromatograph and a double bond analyser (ADS-4). The possibilities offered by the method are compared with those well known for determining MW and MWD of polyisobutylene.

Polymerization of ethylene in the presence of alkoxy-(aroxy)titanium trichlorides and tri-isobutylaluminium☆

Abstract In polymerization of ethylene in the presence of alkoxy-(aroxy)titanium trichloride-tri-isobutylaluminium catalytic systems, the introduction of the RO-groups in the Ti 4+ compound has the effect of causing rapid stabilization of the active centres and the appearance of a long period of polymerization, at a constant rate with the simple kinetic relationship w pol = k p ·[catalyst]·[C 2 H 4 ]. The catalytic activity of the systems is dependent on the nature of the RO substitunt in the ROTiCl 3 : : p -BrC 6 H 4 O>C 6 H 5 O>C 12 H 25 O>C 4 H 9 O. The ROTiCl 3 R 3 Al catalytic systems have a number of characteristic properties, from which the conclusion may be drawn that the RO groups function as “micro-carriers” of active centres.

Some patterns of the synthesis of aromatic polyketones by precipitative polycondensation

The authors have studied the patterns of the synthesis of aromatic polyketones by the reaction of electrophilic substitution on precipitative polycondensation of diphenyl oxide with isophthaloyl chloride, diphenyl oxide with the diacid chloride of 3,3-bis(4′-carboxyphenyl) phthalide and homopolycondensation of p-phenoxybenzoyl chloride in solvents of varied nature. It is shown that growth of the polyketone macromolecules also continues on isolation of the polymer-catalyst complex from solution into a separate phase. The structure of the polymers formed has been established.

The cationic degradation of polyisobutylene

Abstract The thermal degradation of polyisobutylene at temperatures above 560°K proceeds as a random free radical degradation of the macrochains. In the presence of aluminium chloride complexes, the decomposition is effected by cationic depolymerization of the macrochains.

Kinetic features of the cationic degradation of polyisobutylene

Abstract Some kinetics regularities of the cationic degradation of polyisobutylene in the presence of aluminium chloride complexes have been studied. The character of the initiation (random or via the end groups) depends on catalyst nature and process conditions. The same dependence is observed for the ratio of the decomposition reactions occurring in parallel at cationic and free radical centres, up to high levels of cationic depolymerization.

Ziegler-Natta catalysts and the reactive centres composition during the stereospecific polymerization of α-olefins

The chemisorption of (CH3)2AlCl on the crystal surfaces of the α- and β-modifications of TiCl3 have been calculated by the “atom-atom” potentials method. The reactive centres were found to have the same composition for 80% α-TiCl3 and 30% β-TiCl3; their amounts diminished when the temperature was raised. These results agree with those given in the literature about the yields of stereospecific α-olefin polymers over the catalytic systems containing the α- and β-forms of TiCl3.

On the nature of the activity of the systems C2H5AlCl2-alcohol in the cationic polymerization of olefins☆

A study has been made of some physico-chemical properties and of the activity of the systems C2H5AlCl2-alcohol in isobutylene polymerization (transformation of isobutylene models). A quantum chemical calculation has been carried out for some models of active centres in these systems. The calculated data agree with the experimental results, which points to the carbocationic activity of alcohol.

Arenonium ions in Gustavson complexes as initiators of electrophilic polymerization of α-olefins☆

Abstract The activity of arenonium ions in Gustavson complexes during polymerization of α-olefins is of the Bronsted type. The relative proton donating capacity of various Gustavson complexes was estimated from their reactivity in the protolysis of C 2 H 5 ·AlCl 2 . The active centres in Gustavson complexes are ion pairs. The aromatic hydrocarbon in Gustavson complexes acts as a regulator of the molecular weight of polymers.

Removal of catalyst in polybutene production by treatment with ion exchange resin

The development of process technology for removal of AlCl/sub 3/ from the reaction mass obtained in the polymerization of butenes by treatment with ion exchange resins is reported. This work also investigated certain reactions that take place in this treatment. It is proposed that the polymerized product should be treated with KU-2-8 cation exchange resin in the H form. The study demonstrates that by the use of resin treatment of the polymerized product that has been prehomogenized with alcohols, it becomes possible to produce low molecular weight polybutenes in a low waste process.