| 摘要 |
A new hydroxylation of phenolic cpds. of the formula (I); R and Ro = H, 1-4C alkyl-cyclohexyl or phenyl - by H2O2 in an acid catalyst comprises effecting the reaction in a ketonic cpd. and a suitable amt. of a solid mineral catalyst with acidic properties. The mineral acid catalyst is pref. of SiO2-Al2O3, SiO2-Ga2O3, SiO2-B2O3; acid or bridged-clays; natural or synthetic zeolites; phosphates of B-Al and Ga; lamellar phosphates of tetravalent metals, i.e. alpha-M(HPO4)2pH2O (M = Ti, Ge, Zr or Sn; p less than Z) lamellar phosphonates (Zr) and acidic oxides (sulphated oxides of Ti, Zr or Fe). The natural clays, from which acidic clays are derived, are pref. based on the T.O.T. structure (smectites, vermiculite and micas): the smectites include montmorillonites Si4(Al2-yMgy)O10(OH)2M+y; beidellites (Si4-xAlx)Al2O10)CH)2M+x; hectorites Si4(Mg3-yLiy)O10(OH)2M+y; stevensites Si4(Mg3-y(O10(OH)2M+2y; saponites (Si4-xAlx)Mg3O10(OH)2M+x. The commercial clays (acidic or not) are treated with an aq. acid soln. Bridged clays are pref. from a smectite (a synthetic beidellite or a montmorillonite. This comprises treatment with a hydroxide of Al, Ni, Co, V, Mo, Rh, Fe, Cu, Ru, Cr, La, Ce, Ti, Ba, Ga, Zr, Nb, Ta or Si (Al(CH)3 is used). The natural zeolite may be a chabazite, clinofitilite, erionite, mordenite, philipsite or offretite. Synthetic zeolites are pref. of ZSM-5, zeolite Y, ferrierite, zeolite X (faujasite), zeolite L, mordenite, zeolite ZSM-11, mazzite and offretite. The zeolite used is esp. acidified zeolite US-Y or a ZSM-5. The cpds. corresp. to the formula Ra-CO-X-Rb (II). Ra and Rb = 1-30C hydrocarbyl, or together form a divalent radical (opt. substd. by halogen atom(s) or gp(s). stable in the reaction conditions). More pref., Ra and Rb = 1-8C alkyl, (Ra = 1-6C alkyl and Rb = phenyl). X = a single bond, -CO-, -CHOH- or -(R)n- (1-4C alkylene and n = 1-16). The ketonic cpd. is pref. a pentanone, acetophenone, or n-valero phenone. The cpd. (I) is pref. phenol, anisole, ortho, para or meta cresol, 4-tertbutyl, 2-methoxy and 4-methoxy phenol: specifically (I) is phenol. The amt. of catalyst w.r.t. phenolic cpd. (I) is 0.1-20% (0.5-10%). The amt. of ketonic cpd. (II) is at least 1 x 10 power (-3) per mole of H2O2, (1 x 10 power (-3) - 10) esp. 0.05-1.0 mole. USE/ADVANTAGE - More esp. the hydroxylation is used to hydroxylate phenols and phenolic ethers, esp. phenol to form hydroquinone and pyrocatechol. The hydroxylation gives improved yields of diphenols and enables easy sepn. of the acid catalyst from the reaction medium at the end of the reaction.
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