Catalysis by hydrogen halides in the gas phase. XIII. Isopropanol and hydrogen iodide

Abstract

Hydrogen iodide catalyses the decomposition of isopropanol into propene and water at 356 to 457°, viz.                            i-C₃H₇OH+HI → C₃H₆+H₂O+HI This is followed by the faster reactions                            C₃H₆+HI → i-C₃H₇I                           i-C₃H₇I+HI → C₃H₈+I₂                         i-C₃H₇OH+I₂ → (CH₃)₂CO+2HI The rates of the initial reaction fit the Arrhenius equation                   k₂ = 10^12.24 exp(-31900/RT) sec^-1 ml mole^-1 and it is believed to be homogeneous and molecular. It is faster than the corresponding reactions with hydrogen chloride and hydrogen bromide in the ratios 100 : 1 and 5 : 1, respectively. For the overall reaction the amounts of the products formed to 70% reaction, computed with the use of rate constants of the individual reactions, agree well with the amounts found by analysis.