Kinetic Investigation of the Reactions Between Triphenylphosphine, Dialkyl Acetylenedicarboxilates and NH-Acid, such as 5,6-Dimethyl Benzimidazole by the UV Spectrophotometry Technique

The work was undertaken to carry out kinetic studies of the reactions between triphenylphosphineand dialkyl acetylenedicarboxylates in the presence of nh-acid, such as 5,6-dimethyl benzimidazole.to determine the kinetic parameters of the reactions, they were monitored by uvspectrophotometery. the second order fits were automatically drawn by the software associatedwith the uv instrument at an appropriate wavelength. the values of the second order rateconstant (k2) were automatically calculated, using standard equations within the program. at thetemperature range studied, the dependence of the second order rate constant (in k2 ) on reciprocaltemperature was in agreement with the arrhenius equation. this provided the relevant plots tocalculate the activation energy of all reactions. furthermore, useful information was obtainedfrom studies of the effect of solvent, the structure of the reactants (different alkyl groups withinthe dialkyl acetylenedicarboxylates) and, also, the concentration of the reactants on the rate ofthe reactions