Radiation chemistry of alcohols. Part XXI. Ultraviolet photolysis (λ 185 nm) of methoxyethanol in the liquid phase

Abstract

The main products of the photolysis (λ 185 nm) of neat liquid methoxyethanol (quantum yields in parentheses) are H₂(0.27), CH₂O (0.19), CH₄(0.15), methoxyacetaldehyde (0.10), ethylene glycol (0.10), ethanol (0.09), and methanol (0.05). The quantum yields of 34 products altogether have been measured. It is concluded that there are two major reactions (i) and (ii), involving homolytic splitting of the O–H and O–CH₃ bonds. Molecular HOCH₂CH₂OCH₃→ H·+·OCH₂CH₂OCH₃(i), → HOCH₂CH₂O·+·CH₃(ii) fragmentation reactions and the homolytic scission of other bonds play a minor role. In the presence of N₂O (saturated solution)ϕ(H₂) is decreased by ca. 10% while ϕ(N₂) is 0.08 indicating that photoionisation processes are only moderately important. In dilute aqueous solution ϕ(H₂) and ϕ(CH₄) are strongly decreased.