Transition metal chlorides, dehydration

However the material obtained was an unprocessable powder. Unlike substituted polyacetylenes, polyacetylene is insoluble, infusible and unstable in air. The discovery of a technique to synthesize the polymer in the form of a free-standing film and the use of electron donors and acceptors to dope it to have metallic conductivity produced intense interest in the polymer in the last two decades. A wide variety of catalyst systems has been described for the polymerization of acetylene. Besides the route via acetylene polymerization, polyacetylene can also be obtained by a two-step route which involves the synthesis of soluble polymer precursors, which are converted to polyacetylene via thermal elimination and transition-metal-catalysed isomerization, as well as by polymerization of cyclooctatetraene , by dehydrochlorination of poly(vinyl chloride) and by dehydration of poly(vinyl alcohol)... 

Tetrakis(hexafluoroisopropoxides) of titanium, zirconium, and hafnium have been prepared by the reaction of sodium hexafluoroisopropoxide in an excess of hexafluoroisopropyl alcohol with the anhydrous metal chloride, and the spectroscopic properties are reported. The authors note that, in their experience, application to the Group IV transition metals of the previously published method for metal hexafluoroisopropoxide synthesis gives poor yields of material containing metal, fluorinated alkoxides, and co-ordinated ammonia. Dehydration of the hydrated metal chloride with methyl orthoformate and addition of hexafluoroisopropyl alcohol, followed by passage of dry ammonia through the solution, gives satisfactory yields for yttrium, lanthanum, neodymium, and erbium. 

BenzoMoxazoles (130) undergo a base-promoted formal arylation using an aromatic acyl chloride, giving product (131) in up to 91% yield. " The reaction proceeds via N-acylation of oxazole to form an iminium intermediate, which hydrates to give a Lewis acetal, ring-opens, extrudes CO, ring-closes and then dehydrates. The reaction avoids the previous use of transition metal ion catalysis, and one example of an alkyl acid chloride is also reported. 

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