The photochemistry of the formation of sulfuryl chloride

A complete apparatus was assembled in order to carry out the photochemical reaction of sulfur dioxide and chlorine. This apparatus was designed so that the gases would be in contact with only the walls of the containing vessel throughout the course of the reaction. Small glass tips, which could be broken by the use of an electromagnet, were used in preference to stopcocks so that the gases would not be in contact with stopcock grease. The gases had to be circulated during the reaction in order to obtain consistent results;The quantum efficiency of the photochemical reaction: SO2+Cl2→SO2Cl 2 was determined at 70°C using light with a wave length of 4358 A from a high-pressure mercury arc. The value for the quantum efficiency was found to be 1.2 +/- 0.2;Rate curves for the reaction at 70°C have been determined for various starting pressures of the two gases. The reaction was found to be first order with respect to the chlorine, and the equation which best describes the curves was found to be: dSO2Cl2 dt=kCl 2;The degree of dissociation of the molecule (SO2Cl2) in the temperature range between 50 and 100°C was investigated. The constants for the dissociation were found from the degree of dissociation and these were used to calculate the DeltaH for the reaction;The DeltaH from the dissociation reaction was used in the calculation of the free energy of sulfuryl chloride. This calculation was made from data available in the literature combined with the DeltaH determined in the dissociation reaction. The calculated values compared favorably with those found in this investigation