Catalysis of cleavage of di-β-naphthyl ether by electron-donating agents: an explanation for the effectiveness of phenols as promoters for coal conversion

1,3,5-Trimethoxybenzene, 1,2-dimethoxynaphthalene, and 1,4-dimethoxynaphthalene are ineffective as catalysts for the hydrogenolysis of di-β-naphthyl ether in tetralin at 450 °C. However, mixtures of these polyethers with phenol are appreciably more effective catalysts than is phenol itself. Mixtures of the dimethoxynaphthalenes with acetic acid or 1,1,1-trifluoroethanol have catalytic ability, even though the individual components are inactive. It is suggested that both electron-donating ability and acidity are factors determining catalytic activity, and a mechanism is proposed involving electron transfer from the catalyst to the protonated diaryl ether.