Alkylation of naphthalene in the presence of molten zinc chloride.

The alkylation of naphthalene with a few kinds of alkylating agents was examined in the reaction temperature range of 200 to 400°C by using a convenient smallsized tubing-bomb as a reactor.With dialkylbenzenes and molten zinc chloride as a catalyst, the transalkylation of naphthalene was conducted. The experimental results are listed in Table 1, which show that the alkylnaphthalenes are produced accompanied with the formation of by-products to some extent.The alkylation of naphthalene with olefins and the above-mentioned catalyst was examined. The results, as summarized in Table 2, reveal that the alkylation also proceeds with some by-products formed.In the case of use of alkylchlorides as an alkylating agent, the naphthalene was alkylated without addition of zinc chloride as shown in Table 3. Accordingly, the alkylnaphthalenes can be efficiently obtained by selecting the proper reaction conditions.