| 摘要 |
Process for the preparation of at least one boric oxide, in anhydrous or hydrated form, of general formula B2O3.xHx2O in which x is a number from 0 to 3, by hydrolysis of methyl borate, in which methyl borate and water are introduced into a hydrolysis zone, and then the product originating from the hydrolysis zone, at least one compound (preferably a hydrocarbon such as, for example, 2,3-dimethylbutane or 2-methylpentane) forming a heteroazeotrope with methanol, the said heteroazeotrope having a boiling point lower than that of the azeotrope formed by methyl borate with methanol and at least one compound which has a boiling point higher than that of methyl borate, the said compound not forming any azeotrope with a boiling point lower than that of the said heteroazeotrope, are introduced into a distillation column, and then the said heteroazeotrope is recovered at the top of the column and a suspension containing at least one boric oxide is recovered at the bottom of the column. A process for oxidising at least one saturated hydrocarbon chosen from the group consisting of cyclohexane and acyclic and cyclic saturated hydrocarbons containing from 7 to 20 carbon atoms in their molecule into a product comprising the corresponding alcohol is also described, according to which the oxidation is performed, in the presence of a boric oxide forming esters with the alcohol formed by oxidation, with the aid of a gas containing molecular oxygen; the oxidation product is hydrolysed to orthoboric acid and into alcohol which is recovered by separation from the organic phase; the aqueous phase containing the boric acid is conveyed to a zone for forming methyl borate which is recovered in the form of its azeotrope with methanol. The recovery of boric oxide from this azeotrope is performed according to the process described above, the recovered boric oxide being recycled to the oxidation stage.
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