82 - 88%Chromat.; 4 - 11%Chromat. |
With hydrogen;sponge cobalt catalyst in water-containing state; In toluene; at 160℃; under 3975.4 - 165017 Torr; for 0.5 - 1h;Product distribution / selectivity; |
To a 1 liter autoclave, 300 ml of toluene, 25 g of a sponge cobalt catalyst in a water-containing state (in which the catalyst amount is 5 g) and 30 g of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol were charged and a gas phase was thoroughly purged with hydrogen, and thereafter the hydrogen pressure was set to 1.5 MPa at ordinary temperature (the pressure means gauge pressure hereinafter). The stirring and heating for the autoclave were started and the temperature thereof was kept to 160 C. When the temperature reached to 160 C., the pressure was 2.2 MPa. The reaction was continued for 1 hr. Then, the autoclave was cooled to room temperature. After the cooling, the pressure showed 1.0 MPa. At this time, the amount of absorbed hydrogen was 104 mol % based on 2,3,5,6-tetrafluorobenzene-1,4-dimethanol charged. Hydrogen inside a reactor was removed, and thereafter the reaction mixture was recovered and the catalyst was filtered. [0059] The reaction mixture was heated under reduced pressure to remove the solvent by distillation, and further by gradually decreasing the pressure, a fraction distilled at 665 Pas at a temperature of from 100 to 105 C. was recovered. The fraction was analyzed with nuclear magnetic resonance spectrum (NMR) analysis and gas chromatography-mass spectroscopy (GC-MS) to identify 98% 2,3,5,6-tetrafluoro-4-methyl-benzyl alcohol. [0060] Further, using the distilled 2,3,5,6-tetrafluoro-4-methyl-benzyl alcohol as an authentic sample, a part of the reaction mixture recovered in the above reaction was analyzed with the gas chromatography internal standard method. In result, the conversion of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol was 94%, the yield of 2,3,5,6-tetrafluoro-4-methyl-benzyl alcohol was 88% (on the basis of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol), and the yield of 2,3,5,6-terafluoro-p-xylene was 4% (on the basis of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol).Example 5 [0068] To a 1 liter autoclave, 600 ml of toluene, 30 g of a sponge cobalt catalyst in a water-containing state (in which the catalyst amount is 6 g) and 60 g of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol were charged and gas phase was thoroughly purged with nitrogen. The stirring and heating for the autoclave were started and the temperature thereof was kept to 160 C. The pressure at this time was 0.28 MPa. Hydrogen was charged to the autoclave to increase the pressure to 0.53 MPa. Then, hydrogen was further fed to the autoclave to keep the pressure at 0.53 MPa, and when the hydrogen absorbing amount reached to 130 mol % based on 2,3,5,6-tetrafluorobenzene-1,4-dimethanol charged while watching the hydrogen flow rate, the reaction was stopped. The reaction required 30 minutes. [0069] Then, the autoclave was cooled to room temperature, gases inside the reactor were removed, and thereafter the reaction mixture was recovered and the catalyst was filtered. [0070] The resulting reaction mixture was analyzed with the gas chromatography internal standard method. In result, the conversion of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol was 99.5%, the yield of 2,3,5,6-tetrafluoro-4-methyl-benzyl alcohol was 82% (on the basis of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol), and the yield of 2,3,5,6-tetrafluoro-p-xylene was 11% (on the basis of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol). |
58%Chromat.; 14%Chromat. |
With hydrogen;rhenium oxide-alumina catalyst; In 1,4-dioxane; at 220℃; under 36003.6 Torr; for 5h;Product distribution / selectivity; |
Example 4 To a 100 ml autoclave, 30 ml of 1,4-dioxane, 1.5 g of a supported rhenium oxide-alumina catalyst and 3.0 g of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol were charged and a gas phase was thoroughly purged with hydrogen, and thereafter the hydrogen pressure was set to 3 MPa at ordinary temperature.The stirring and heating for the autoclave were started and the temperature thereof was kept to 220 C. When the temperature reached to 220 C., the pressure was 4.8 MPa. The reaction continued for 5 hr. Then, the autoclave was cooled to room temperature and the pressure after the cooling showed 2.6 MPa. At this time, the amount of absorbed hydrogen was 116 mol % based on 2,3,5,6-tetrafluorobenzene-1,4-dimethanol charged.hydrogen inside a reactor was removed, and thereafter the reaction mixture was recovered and the catalyst was filtered.The resulting reaction mixture was analyzed with the gas chromatography internal standard method.In result, the conversion of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol was 83%, the yield of 2,3,5,6-tetrafluoro-4-methyl-benzyl alcohol was 58% (on the basis of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol), and the yield of 2,3,5,6-terafluoro-p-xylene was 14% (on the basis of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol). |
40%Chromat.; 7%Chromat. |
With hydrogen;sponge cobalt catalyst in a water-containing state; In 1,4-dioxane; at 160℃; under 3750.38 Torr; for 4h;Product distribution / selectivity; |
Example 2 To a 100 ml autoclave, 30 ml of 1,4-dioxane, 2.5 g of a sponge cobalt catalyst in a water-containing state (in which the catalyst amount is 0.5 g) and 3.0 g of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol were charged and a gas phase was thoroughly purged with hydrogen, and thereafter the hydrogen pressure was set to 0.3 MPa at ordinary temperature.The stirring and heating for the autoclave were started and the temperature thereof was kept to 160 C. When the temperature reached to 160 C., the pressure was 0.5 MPa. hydrogen was fed to the autoclave to keep a pressure at 0.5 MPa, and when the hydrogen absorbing amount reached to 145 mol % based on 2,3,5,6-tetrafluorobenzene-1,4-dimethanol charged while watching the hydrogen flow rate, the reaction was stopped.The reaction required 4 hr. Then, the autoclave was cooled to room temperature.hydrogen inside a reactor was removed, and thereafter the reaction mixture was recovered and the catalyst was filtered. The resulting reaction mixture was analyzed with the gas chromatography internal standard method.In result, the conversion of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol was 69%, the yield of 2,3,5,6-tetrafluoro-4-methyl-benzyl alcohol was 40% (on the basis of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol), and the yield of 2,3,5,6-terafluoro-p-xylene was 7% (on the basis of 2,3,5,6-tetrafluorobenzene-1,4-dimethanol). |