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Quantum yi e lds of the major produ cts formed in the far ultravi ole t photolys is of CH,C DCI (C2 H2 , C, HD , C,HoD, C, H2 D" and 1,3·C, H,D,) have bee n de te rmin e d at 147 nm (8.4 e V), 123.6 nm (10.0 eV), a nd 104.8-106.7 nm 01.6-11.8 e V). The quantum yield of th e s tab le vinyl rad ica ls whi c h can be un· ambiguous ly asc ribed to the primary process (C H2CDCI + hll~ CH,C D+ CI) is 0.3 a nd 0.05 at 147 and 123.6 nm, res pe c tive ly. The sharp d ec rease in the yie ld of vinyl radicals with the in c re ase in e ne rgy of the in cid e nt photon beam is in part attribute d to the deco mposition of inte rnally e xcited vinyl radica ls to give acet yle ne as a produ c t. At 147 nm , th e co mbin ed yield of acet yle ne plu s vinyl rad icals is 0.95 ± 0.05. At the s horte r wa ve length s, approximate ly one acet yle ne molecul e is form ed per e lectronically excite d vinyl c hloride mol ec ule. It is conclude d that th e dissociative process: C2 HaCI* ~ C,H, + H + CI, occ urrin g via a C, Ha or C,H, CI inte rm e diate ade qu ate ly acco unts for the reo active ne utral s pecies form ed at higher photon e ne rgies. Isotopi c la belin g e xpe rim e nts s how that the hyd roge n atoms are d etac hed from both pos iti ons of th e pare nt molecule. Ethylene whic h is a produ ct over the e ntire wavel ength range is in part form e d via the reaction : H* + C,HaC I ~ C2H .. + CI, whe re H* re presents a translationa Uy e xcited hydrogen atom. The C2H2DC I+ ion s formed at 104.8 -106.7 nm with a quantum yie ld of 0.47 do not contribute to th e form ation of acetyle ne or vinyl radi c al s. In the gas phase radiolysis of vinyl c hlorid e, acetyl e ne (G -1. 5) is ma inly form e d in th e di ssocia tion of ne utra l e lectronica ll y excited vinyl c hlorid e molec ules. From this value, we may es tim ate th at the ratio of neutral excited molec ul es formation to ionization in th e rad iolys is of vinyl c hl orid e is 0.39. Vinyl ions, whi c h a re also prod uced (G -0.28-0.35) react ma inl y by addition to vi n yl c hlorid e.

The photolysis of methyl acetate has been investigated in the vapor phase over the temperature range 29 to 217°C at varying light intensities and initial pressures. The main primary step is a split of the ester molecule into CH3CO and CH3O radicals. The following reactions involving methoxy radicals have been established: CH3O+CH3→CH2O+CH4CH3O+CH3→CH3OCH3CH3O+CH3COOCH3→CH3OH+CH2COOCH3.As activation energies for reactions (A) and (C) were obtained EA≤1.5 kcal and EC≃4.5 kcal. No information could be obtained regarding the extent to which reaction (D) occurred. 2 CH3O→CH3OH+CH2O.An activation energy of 10 kcal was obtained for the abstraction of a hydrogen atom from methyl acetate by methyl radicals.