The addition of iodine to certain unsaturated compounds and hydrogen iodide catalysis.

Abstract

Much of the work carried out in the past upon the addition of iodine to unsaturated compounds has been done using aprotic solvents, Hertz and Mylius (6) found that in the reaction between allyl alcohol and iodine in the dark in carbon tetrachloride, carbon disulphide and chloroform, bimolecular constants were obtainable in individual experiments but that these varied with the concentrations Muller (7) studied the iodination of oleic acid in carbon tetrachloride and ethyl acetate and found bimolecular kinetics in each case. Schemacher (8) concluded that the reaction between iodine and ethylene in carbon tetrachloride was homogeneous and proceeding by an atom chain mechanism. Moelwyn-Hughes and Legard (9) studied the iodination of B phenyl propiolic acid in aqueous solution using potassium iodide and iodine. These results were complicated by the presence of K1 3. Bythell and Robertson (10) studied the addition of iodine to various unsaturated substances in both protophilic and aprotic solvents. The protophilic solvents such as acetic acid and nitrobenzene gave brown solutions whereas the aprotic solvents gave violet solutions e.g. carbon tetrachloride, chloroform and hexnae. Ogg and Priest (11) have show that the thermal reaction between iodine and cyclopropene in the gas phase is homogeneous and proceeds by a chain reaction initiated by iodine atoms. Groh and Szelestey (12) studied the iodination of erucic acid in the dark in carbon tetrachloride and carbon disulphide. They found that the reaction velocity is proportional to the concentration of the acid and to the cube of the iodine concentration. They expressed tha reaction as I6 + E ⇆ E.1 2 + 2I2