Chain Multiplication of Fatty Acids to Precise Telechelic Polyethylene

Starting from common monounsaturated fatty acids, a strategy is revealed that provides ultra-long aliphatic alpha,omega-difunctional building blocks by a sequence of two scalable catalytic steps that virtually double the chain length of the starting materials. The central double bond of the alpha,omega-dicarboxylic fatty acid self-metathesis products is shifted selectively to the statistically much-disfavored alpha,omega-position in a catalytic dynamic isomerizing crystallization approach. Chain doubling by a subsequent catalytic olefin metathesis step, which overcomes the low reactivity of this substrates by using waste internal olefins as recyclable co-reagents, yields ultra-long-chain alpha,omega-difunctional building blocks of a precise chain length, as demonstrated up to a C-48 chain. The unique nature of these structures is reflected by unrivaled melting points (T-m = 120 degrees C) of aliphatic polyesters generated from these telechelic monomers, and by their self-assembly to polyethylene-like single crystals.