The Action of Aluminum Chloride on Benzene and Cyclohexane

Abstract

When 1-bromoethynyl-l-cyclohexanol was treated similarly with pyridine and thionyl chloride a mixture of 1bromoethynyl-1 -cyclohexene and 1 -(chlorobromovinyl) -1cyclohexene was formed. From 23 g. of the hexanol, there was produced 4 g. of product distilling at 120-130°( 34 mm.) and 4.5 g. at 130-140°. Summary l-a-Chlorovinjd-1-cyclohexene was prepared by the action of thionyl chloride on ethynylcyclohexanol in pyridine and some ethynyl-cyclohexene was obtained also.1-Ethynyl-lchlorocyclohexane and cyclohexylidenevinyl chloride were proved absent.1 -Phenylethynyl-1 -cyclohexanol, 1 -chloroethynyl-1 -cyclohexanol and 1 -bromoethynyl-1 -cyclohexanol underwent more dehydration than chlorination by thionyl chloride or phosphorus pentachloride.1-Ethyl-l-chlorocyclohexane was prepared readily from 1-ethyl-l-cyclohexanol but 1-phenyl-1-cyclohexanol resisted chlorination.Evanston, III.

The Friedel-Crafts Syntheses.

“…Benzene itself may introduce various alkyl groups into aromatic nuclei. On refluxing benzene with aluminum chloride, ethylbenzene (206) and cyclohexylbenzene (443) may be isolated, among other products. This is further discussed under the subject of mechanism (p. 378).…”

“…It is interesting to note that oxygen may be introduced into a nucleus as inert as benzene by means of the Friedel-Crafts reaction. It is an established fact that when oxygen is not excluded from Friedel-Crafts syntheses, one of the complicating reactions is the introduction of oxygen into the nucleus to form phenolic substances (443,206).…”

“…Benzene, for example, with aluminum chloride yields a minute quantity of diphenyl (206). However, with other hydrocarbon types, this reaction is prevalent.…”

“…Even the cycloparaffins tend to couple with evolution of hydrogen as the aromatic nuclei do (296,293,206). The liberated hydrogen may cause reductions of the other reactants.…”

“…Besides those cleavage reactions already mentioned, the aromatic rings may undergo complete decomposition to form fragments that undergo simultaneous reduction to yield alkyl groups that will enter the remaining nuclei. This process has been pictorially described as "destructive alkylation" (206). The over-all reaction is represented simply:-CeHe c2h5<…”