Dolezal Zdenek, Kubinec Róbert, Sedlácek Jan, Pacáková Vera, Vohlídal Jiri
Department of Analytical Chemistry, Faculty of Sciences, Charles University, Prague, Czech Republic.
J Sep Sci. 2007 Mar;30(5):731-9. doi: 10.1002/jssc.200600388.
A series of substituted acetylenes has been polymerized with WOC14/Ph4Sn metathesis catalyst and [Rh(cod)OMe]2 insertion catalyst, and the thermal degradation of the polyacetylenes prepared has been studied using pyrolysis capillary gas chromatography (Py-GC) with flame ionization and mass spectrometric detection to obtain information on the effect of the catalyst on the head-tail (H-T) isomerism of polyacetylenes (poly(phenylacetylene), poly[(4-methylphenyl)acetylene], poly(benzylacetylene), poly((2-fluorophenyl)acetylene], poly[(3-fluorophenyl)acetylene], and poly[(4-fluoro-phenyl)acetylenel). Cyclotrimers have been found to be the main pyrolysis products in all cases. Direct Py-MS connection was used to determine the temperature profiles of the released pyrolysis products. 1,3,5-Trisubstituted benzenes were found to be the predominant pyrolysis products of the polymers prepared with the insertion catalyst, which proves the presence of long head-to-tail sequences of monomeric units in these polyacetylenes. On the other hand, both 1,2,4- and 1,3,5-trisubstituted benzenes are present in significant amounts in the pyrolysis products of polymers prepared with the metathesis catalyst, which proves the presence of a significant content of the head-to-head (HH) and tail-to-tail (TT) linkages in these isomers of polyacetylenes. Contents of the regular (HT) and inverse (HH-TT) monomer linkages (RML and IML, respectively) in polymer chains were determined from the relative amounts of di-, tri-, and tetrasubstituted benzenes found in the Py-GC products.
一系列取代乙炔已使用WOC14/Ph4Sn复分解催化剂和[Rh(cod)OMe]2插入催化剂进行聚合，并使用带有火焰离子化和质谱检测的热解毛细管气相色谱法（Py-GC）研究了所制备聚乙炔的热降解，以获取有关催化剂对聚乙炔（聚（苯乙炔）、聚[（4-甲基苯基）乙炔]、聚（苄基乙炔）、聚[（2-氟苯基）乙炔]、聚[（3-氟苯基）乙炔]和聚[（4-氟苯基）乙炔]）头-尾（H-T）异构现象影响的信息。在所有情况下，环三聚体均被发现是主要的热解产物。使用直接Py-MS连接来确定释放的热解产物的温度分布。发现1,3,5-三取代苯是用插入催化剂制备的聚合物的主要热解产物，这证明了这些聚乙炔中存在长的单体单元头对尾序列。另一方面，在使用复分解催化剂制备的聚合物的热解产物中，1,2,4-和1,3,5-三取代苯均大量存在，这证明了这些聚乙炔异构体中存在大量的头对头（HH）和尾对尾（TT）键。根据Py-GC产物中发现的二、三、四取代苯的相对量，确定了聚合物链中规则（HT）和反向（HH-TT）单体键（分别为RML和IML）的含量。
