Polymerization of some terminal alkynes by Ziegler-Natta catalyst systems: Fe(RCOO)3-AlEt3

Abstract

The polymerization of 1-hexyne, 3-methyl-1-pentyne, 4-methyl-1-pentyne, and teri-butylacetylene was carried out with the following Ziegler-Natta type initiating systems: Fe(prp)3-AlEt3, Fe(chc)3-AlEt3, Fe(naph)3-AlEt3 (prp = propionate, chc = cyclohexanecarboxylate, naph = naphtenate). The catalytic efficiency of these complexes was almost identical towards a same monomer. The polymer yield (0-100%) was highly influenced by the bulkiness of the substituent directly attached to a sp carbon. The molecular weights of the different polyalkynes obtained were relatively high (4 × 104-105). 13C and 1H NMR analyses of the polymers revealed a preferential orientation of the polymerization with these initiating systems; that is, the trans-configuration fraction was as high as 70%. © 1999 Elsevier Science Ltd. All rights reserved.