A Simple and Efficient Process for the Preparation of 1,6-Dimethoxynaphthalene

1,6-Dimethoxynaphthalene (1,6-DMN) was prepared by the O-dimethylation of 1,6-dihydroxynaphthalene (1,6-DHN) with dimethyl sulfate (DMS) in the presence of sodium hydroxide and additives in different solvents. The main reaction determining factors were divided into three categories with respect to yield and purity of 1,6-DMN: (1) Type of solvents and adding methods of NaOH had the highest effect on the results. (2) Amount of DMS and concentration of NaOH were less important. (3) Reaction time and temperature were the least important factors. The best reductant was Na(2)S(2)O(4), and it was only under N(2) atmosphere that yield and purity were also good. The improved process provides more than 99% yield, which considerably reduces the cost of 1,6-DMN, and more than 98% purity eliminates the purification process in the follow-up industrial production.