| 摘要 |
<p>PURPOSE:To produce 1,2,3,4-tetrafluorobenzene useful as an intermediate of agricultural chemicals and pharmaceuticals, easily, in high yield, in an industrial scale, by decarbonating 3,4,5,6-tetrafluorophthalic acid in an aqueous medium at a specific temperature under autogeneous pressure. CONSTITUTION:The objective 1,2,3,4-tetrafluorobenzene can be prepared economically, by carrying out the decarbonation of 3,4,5,6-tetrafluorophthalic acid in an aqueous medium 210-300 deg.C, preferably 230-270 deg.C, further preferably in the presence of one or more catalysts selected from copper, zinc, cadmium, iron, cobalt, or nickel, the oxide, hydroxide or carbonate of said metals, expecially copper powder, cupric oxide or zinc oxide at 100-270 deg.C, especially 160-240 deg.C under autogeneous pressure. The amount of the catalyst is preferably about 0.1-10pts.wt., especially 0.3-2pts.wt. per 100pts.wt. of the above raw material.</p> |
