Microwave-assisted regioselective alkylation of naphthalene compounds using alcohols and zeolite catalysts

Regioselective alkylation of naphthalene compounds with alcohols smoothly proceeded in the presence of zeolite catalysts under microwave irradiation. A H-mordenite (H-M) zeolite catalyst (SiO2/Al2O3 ratio = 240) showed the highest efficiency. In the microwave reactions, high reaction rates and high selectivities for 2,6-dialkylnaphthalenes were achieved. In the best case for the reaction of 2-isopropylnaphthalene with isopropyl alcohol, the conversion and the selectivity were 43.5% and 66.4%, respectively. In di-tert-butylation of naphthalene with tert-butyl alcohol, the conversion and the selectivity reached 86.5% and 70.4%, respectively. The conversions and the selectivities were generally higher than those obtained by conventional oil bath heating.

Graphical abstractMicrowave-assisted regioselective alkylation of naphthalene compounds (2-isopropylnaphthalene, naphthalene) with alcohols (isopropyl alcohol, tert-butyl alcohol) smoothly proceeded in the presence of a H-mordenite catalyst (SiO2/Al2O3 ratio = 240) to give the corresponding 2,6-dialkylnaphthalenes with high selectivities. The conversions and the selectivities were generally higher than those obtained by conventional oil bath heating.Figure optionsDownload full-size imageDownload high-quality image (92 K)Download as PowerPoint slide