The Unsensitised Photolysis of But‐1‐ene at 1849 Å

On photolysis at 1849 Å but‐1‐ene yields 25 hydrocarbon products and a solid polymer. In order to elucidate the mechanism the effects of added gases, time, pressure of reactant gas and temperature were investigated. A free radical mechanism is postulated in which there are six primary reactions to account for the products and their relative yields. The two major primacy reactions are cleavage of the C‐C and C‐H bonds in the β position to the double bond in a 6:1 ratio. Addition of foreign gases to the system caused a decrease in the product yield which was shown to be due to quenching of the reaction. This is attributed to the collisional deactivation of an excited state intermediate of which the decomposition This is attributed to the collisional deactivation of an excited state intermediate of which the decomoposition lifetime has been estimated to lie within the values of 2.6 to 6.4 · 10 −10 sec.