Hydrogenolysis in an alkaline medium of lignin, either crude or contained in woods of various species, is carried out in a solvent, at not below 100 deg.C and at an initial H2 pressure of not less than 30 bars, in presence of a catalyst obtd. by redn. of a Ni(II) salt by (a) an alkali borohydride in an aq. or ethanolic medium, or (b) by a Na hydride-Na alcoholate system in tetrahydrofuran. The catalyst may be pre-prepd. and stored in an inert atmos., or may be prepd. on the vegetable fibre. Hydrogenolysis is pref. at 130-250 deg.C and an initial H2 pressure of 60-130 bars, in water or a mixt. of water and water-miscible organic solvent. The amt. of catalyst is esp. 0.5-1.5 milliatoms-g of Ni/g of wood. The prod. is a suspension contg. catalyst, ash and possibly residual pulp in an alkaline soln. of Na phenolates. The suspension is acidified to pH 1 with dil. HCl, and the phenols are extracted with ether. (I) and (II) can be isolated by chromatography, by vacuum distn., or by extn. with hexane or cyclohexane. Used in prepn. of 4-ethyl-2-methoxy-phenol (I) and 2,6-dimethoxy-4-ethylphenol (II). The prepn. gives almost solely (I) (from soft woods) and (II) (from hard woods). The lignin conversion is about 40 wt.%.
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