49.9 g of the 4-(4-nitro-3-benzyloxyphenoxy)-4′-(4-benzyloxycarbonylphenoxy)octafluorobiphenyl prepared as described in Example 2 (0.065 mol) are dissolved in 400 ml of a mixture of tetrahydrofuran and ethyl acetate (volume ratio 1:1), and 5 g of Pd/C (palladium/carbon) are then added to the solution. The mixture is then hydrogenated using hydrogen at a pressure of 1 bar at room temperature in an autoclave with vigorous stirring; the reaction is terminated after 3 days. The yellow-beige solution is evaporated to half in a rotary evaporator and left to stand overnight at room temperature, during which the reaction product precipitates out in crystalline form. The reaction product is then separated off and dried for 48 hours under nitrogen at 40° C./10 mbar in a vacuum drying cabinet (yield: 91%).
