COMPARISON OF CHLORINATED SOLVENT ALUMINUM REACTION INHIBITORS

Twenty-two compounds were evaluated as inhibitors, at reflux temperatures, of the reaction with aluminum of 1,1-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane, and a solution of 10 vol % toluene in 90 vol % methylene chloride. Minimum concentrations needed to inhibit the reaction are tabulated. Good 1,1,1-tri-chloroethane-aluminum reaction inhibitors are not necessarily among the best inhibitors for other chlorinated solvents. Addition of an aromatic diluent, such as toluene, to methylene chloride severely increases its corrosiveness toward aluminum. It is suggested that inhibition of the aluminum-methylene chloride reaction involves complexing of the chemisorbed aluminum chloride product with electronegative groups of the inhibitor. Successful inhibition then demands a complex that has only very limited solubility in the solvent system. Sixty compounds are ranked in order of their effectiveness in inhibiting reaction of the methylene chloride-toluene solvent system with aluminum. © 1979, American Chemical Society. All rights reserved.