Ziegler‐type propene polymerization catalyst systems involving tributyl phosphite as modifier

Abstract

AbstractTributyl phosphite (1) was studied as modifier of heterogeneous TiCl3/(C2H5)2AlCl propene polymerization catalyst systems. When used as the sole modifier, 1 was found to produce catalyst systems with substantially improved stereospecificity and only slightly depressed activity relative to the unmodified catalyst system. Binary modifier packages consisting of 1 and bis‐(tributyltin) sulfide lead, apparently through synergism, to catalyst activities surpassing that of the unmodified catalyst system and to excellent stereospecificity (hexane extractables; 1,6–2,1%). Catalyst systems modified with 1 and triphenylantimony sulfide were also demonstrated to exhibit activities approaching or even exceeding that of the unmodified catalyst system with 2,1–2,3% hexane extractables, while systems involving 1 and triethyl thiophosphate as modifiers are more stereospecific (hexane extractables: 1,80%), but somewhat less active than the preceding system. Possible interactions and reactions of 1 with the components of the catalyst system are discussed.