Cleavage of aryl ether

Problem 19.15 Why does cleavage of aryl ethers, ArOR, with HI yield only ArOH and Rl ... 

Treating a bituminous coal with potassium hydroxide in glycols at 250°C yields a largely soluble product that results from the reduction of polycyclic aromatics and the cleavage of aryl ether linkages. The reduction in aromaticity was demonstrated in two ways. First, the fraction of aromatic carbons ( J of the soluble product, which was determined by NMR, was compared with the of the whole coal determined by fluorination. Secondly, the aromatic acids produced in a selective oxidation of both the product and coal were compared, and evidence for ether cleavage was obtained from the oxidation results. The effects of rank and different protic solvents on the reaction were examined. 

Engesser, K.H., V. Strubel, K. Christoglou, P. Fischer, and H.G. Rast. 1989. Dioxygen-olytic cleavage of aryl ether bonds l,10-dihydro-l,10-dihydroxyfluorene-9-one, a novel arene dihydrodiol as evidence for angular dioxygenation of dibenzofu-ran. FEMS Microbiol. Lett. 65 205-210. 

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