Di-tertiary Butyl Peroxide Research Articles

Rates of initiation and chain transfer constants in the polymerization of methyl acrylate

AbstractBy a study of bulk polymerization of methyl acrylate at 55°–75°C with benzoyl peroxide, ditertiary butyl peroxide, methyl ethyl ketone peroxide and tertiary butyl hydroperoxide as catalysts, rates of initiation, chain transfer constants for the monomer and the catalyst have been evaluated. Determination of temperature coefficients for all the rate constants have been made. Values for the catalyst efficiencies and thermal rate constants for initiation are given. Calculated and experimentally determined chain lengths are compared. Certain aspects of polymerization of methyl acrylate are compared with styrene and methyl methacrylate.

The kinetics of the succinoxidase

Rate equations for the enzymatic oxidation of succinic acid are derived on the assumption that when a single molecule of substrate combines with an enzyme molecule, it can do so with either one or two sites on the enzyme, and that oxidation occurs only in the second case. In addition it is assumed that the product of the reaction, fumaric acid, combines reversibly with the enzyme. With certain enzyme preparations the data fitted such an equation satisfactorily. In others the rate was that of a first-order reaction, but addition of cytochrome changed it to the former type. It was concluded that the transfer of hydrogen to oxygen was a first-order reaction and dominated the whole rate when enzyme preparations were used which had been washed relatively free of cytochrome. When the limiting factor was succino-dehydrogenase the rates followed the new equation. Criteria for recognizing noncompetitive inhibition are given, and inhibition by di-tertiary butyl peroxide was shown to be of this type.