Abstract
Long-chain alkylbenzenes (alkyl: C4∼C14) were chloromethylated at 70∼75°C by passing hydrogen chloride for 6∼7h in the presence of paraformaldehyde, zinc chloride and acetic acid. Long-chain alkylbenzyl chlorides were obtaind in good yields (60∼75%) and the chloromethyl derivatives were transformed into the corresponding alkyltoluenes by hydrogenolysis. The isomer contents of the resulting products were examined by infrared spectrometry (IR) and gas-liquid chlomatography (GC).
The analytical results sho wed that the para-substituted compounds (73∼83%) increased with the increase of the length of alkyl chains (C4∼C14), whereas the ortho compounds (24∼15%)decreased. The meta compounds were formed in small amounts (2.8∼1.9%) and decreased slightly with the increase of the chain length. Determination of o-, m- and p-alkyltoluenes by IR was carried out with fair accuracy by using the homologues with other alkyl chain as a standard, even when their standard substances are not available.
