Herman Casper Meinders, Nanno Prak, G. Challa
Apr 1, 1977
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0
Influential Citations
7
Citations
Journal
Macromolecular Chemistry and Physics
Abstract
The kinetics of the oxidative dimerization of ethynylbenzene (1) at 25°C was studied in a mixture of 1,2-dichlorobenzene and pyridine, catalyzed by soluble complexes derived from copper(I) chloride and pyridine derivatives. The influence of the concentrations of cosolvent pyridine, of copper salt, of 1, and of the ligands 2-phenylpyridine (4) and partially 2-pyridyl substituted atactic polystyrene (3) on the initial reaction rate was determined. In the initial stages the reaction is first order in [CuCl]0 up to the solubility limit of the complex at [CuCl]0 = 2,8 · 10−3 mol dm−3. The order in 1 is 0,5 in the case of the pyridine complex and 2 in the case of the complex with the polymeric ligand 3. These results are in agreement with a previously proposed reaction scheme. It was also found that the cosolvent pyridine acts as a slightly activating ligand reaching a maximum reaction rate only for very high N/Cu ratios. The above mentioned ligands 3 and 4 can rapidly displace a pyridine ligand from the complex yielding much more active complexes.