1. The destructive alkylation of benzene with pentane over an aluminosilicate catalyst under autoclave conditions have effected for the first time. 2. The effects of the duration of reaction, temperature, and amount of catalysts on the yield of reaction products were investigated. 3. It was shown that destructive alkylation of benzene with an equimolecular amount of pentane under autoclave conditions results in the formation of a mixture of alkylated aromatic hydrocarbons (in an amount equal to 34% by weight of the original mixture) together with gaseous hydrocarbons (23% by weight on the original mixture). 4. The alkylated aromatic hydrocarbons obtained in the autoclave experiments were investigated, and it was shown that they included toluene, ethylbenzene, isopropylbenzene, xylenes, and ethylmethylbenzene. The gaseous reaction products were investigated and it was shown that they consisted mainly of saturated hydrocarbons.