Potassium Propylbenzene

In the presence of alkah metals such as potassium and sodium, toluene is alkylated with ethylene on the methyl group to yield, successively, normal propylbenzene, 3-phenylpentane, and S-ethji-S-phenylpentane (21). 

Potassium hydroxide, alcoholic, 7, 77 Potassium iodide, 4, 37 7, 14, 58 Potassium permanganate, 7, 18 8, 68 Potassium Phthalimide, 7, 8, 78 Potassium sulfate, 6, 2 Prest-o-lite tank, 8, 10 Propane-1, 1, 2, 3-Tetracarboxyuc Ester (Ethyl), 4, 29, 77 m-Propylbenzene, 4, 59 t 50-Propyl chloride, 5, 28 i-Propy] chloride, 5, 28... 

Tn 1955 Pines and Schaap (1) discovered that toluene was alkylated by ethylene in the presence of sodium or potassium metal or, more specifically, their organometallic derivatives. This reaction requires a high temperature (about 200°C) and considerable olefin pressure the organometallic catalyst is essentially insoluble in the reaction medium. The catalyst cycle—for example, in the side-chain ethylation of toluene— involves a benzyl carbanion which adds to ethylene to form a primary alkyl carbanion. The latter immediately abstracts a proton from the excess toluene reactant to form n-propylbenzene and to reform the energetically-favored benzylic anion in a catalytic cycle. 

On further conversion of the n-propylbenzene, additional benzylic hydrogens are ethylated. The high rate of transmetalation involving the primary aliphatic organosodium or potassium intermediates and the alkyl-... 

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