Water → 1,4-Benzenedimethanol, 2,5-difluoro-

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A solution of 63.2 g (0.265 mols of 2,3,5,6-tetrafluoroterephthalic acid (m.p. 268 - 271° C., obtainable from Pierce-Chemical, Rockford, Ill., U.S.A., in 450 ml of tetrahydrofuran are introduced in the course of 1 hour into a solution of 40.3 g (1.06 mols) of lithium aluminium hydride in 1200 ml of tetrahydrofuran. The reaction mixture is refluxed for 24 hours, then cooled to 10° C. and treated carefully with 40 ml of 15% sodium hydroxide solution and finally with 120ml of water. The white precipitate is filtered off, washed with 500 ml of tetrahydrofuran, and the clear filtrate concentrated at 60° C. under vacuum. 37.9 g of slightly yellow-colored crystals are obtained. This-layer chromatography reveals them to be a mixture of at least three substances. To isolate a unitary substance, the batch is dissolved in 500 ml of ether, 2.8 g of insoluble constituents are removed by filtration, and the ethereal solution concentrated to one-third its volume. It is then treated with 35 ml of pentane and cooled to 10° C., white crystals precipitating. After two recrystallizations from ether+pentane, 3.4 g of fine needles are obtained which melt at 107-109° C.

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