Fluorocarbon-aluminium compounds. III. Reactions of Heptafluoro-3-iodopropane, 1,1,1,2,2-Pentafluoro-3-iodopropane, and Heptafluoro-2-iodopropane with lithium tetrahydroaluminate

Abstract

The complex LiA1(CFzCF2CF3)H21 which is formed from heptafluoro-3- iodopropane and lithium tetrahydroaluminate has been studied in solution. 1,1,1,2,2- Pentafluoro-3-iodopropane and heptafluoro-2-iodopropane also react with lithium tetrahydroaluminate in diethyl ether or tetrahydrofuran solution to form the unstable complexes LiA1(CH2CF2CF3)H21 and LiA1[CF(CF3)2]H21 respectively. The formula- tion of each fluorocarbon-alane compound is indicated by n.m.r. spectroscopic studies and by a quantitative investigation of the products of (i) thermal degradation and (ii) hydrolysis. Of the three fluoroalkyl-alane complexes, LiAl(CHzCF2CF3)Hd is the least stable thermally. I t decomposes readily in solution to give 2,3,3,3-tetra- fluoropropene in high yield. The perfluoroalkyl-alane complexes LiAl(CFzCF2CFs)HnI and LiAl[CF(CF3)2]H21 both decompose in solution to form fluoro-alkane and -alkene compounds.