Chelazzi David, Ceppatelli Matteo, Santoro Mario, Bini Roberto, Schettino Vincenzo
LENS, European Laboratory for Non-Linear Spectroscopy and INFM, Via N. Carrara 1, I-50019, Sesto Fiorentino (FI), Italy.
J Phys Chem B. 2005 Nov 24;109(46):21658-63. doi: 10.1021/jp0536495.
Ethylene is the simplest organic molecule containing a double bond and is the starting monomeric unit in the synthesis of polyethylene, one of the most largely produced polymers. Here we report a high pressure infrared study of ethylene at room temperature. A polymerization reaction is observed when the crystalline phase I is compressed above 3.0 GPa. The reaction kinetics was investigated at two different pressures, 3.6 and 5.4 GPa. The recovered product was identified in both cases as polyethylene, but while a conformationally disordered and branched low-density polymer is obtained at the highest pressure, a high-density crystalline polymer is obtained at 3.6 GPa. A reaction mechanism was proposed on the basis of the kinetic data and the structural information.
乙烯是含有双键的最简单有机分子，是合成聚乙烯（产量最大的聚合物之一）的起始单体单元。在此，我们报道了室温下乙烯的高压红外研究。当晶相I在3.0 GPa以上被压缩时，观察到聚合反应。在3.6 GPa和5.4 GPa这两个不同压力下研究了反应动力学。在两种情况下回收的产物均被鉴定为聚乙烯，但在最高压力下得到的是构象无序且支化的低密度聚合物，而在3.6 GPa时得到的是高密度结晶聚合物。基于动力学数据和结构信息提出了反应机理。
