Radiation-induced reactions of benzoyl chloride and acrylates in solution. A pulse radiolysis study

Abstract

Using electron pulse radiolysis with optical detection, the radiation-induced reactions of benzoyl chloride and acrylates were studied in tetrahydrofuran and acetonitrile solution at room temperature. In both solvents electron transfer leads to the formation of transient radical anions of acrylates (k≈2–3×10¹⁰ dm³ mol⁻¹ s⁻¹) and of benzoyl chloride (k≈3×10¹⁰ dm³ mol⁻¹ s⁻¹). The latter dissociates into chloride ion and the benzoyl radical (k=3×10⁶ s⁻¹), whereas the acrylate anion transforms by protonation into a ketyl-type radical. In mixed solutions a fast electron transfer from acrylate anions to benzoyl chloride is found (k≈1×10¹⁰ dm³ mol⁻¹ s⁻¹). The benzoyl chloride anion reacts with the monomer (k=2.8×10⁹ dm³ mol⁻¹ s⁻¹) with simultaneous release of Cl⁻, forming species which may initiate polymerization. In the presence of oxygen the formation of benzoylperoxy radicals (k=1.6×10⁹ dm³ mol⁻¹ s⁻¹), showing a strong absorption band in the near-UV (λ_max=400 nm), is observed.