New bis:imidazolyl carbinol cpds. - prepd. via imidazolyl-lithium cpd., used in sepg. platinum gp. metals, e.g. from used catalysts

摘要

C1-bridged (a)symmetric bisimidazole cpds. of formula (I) (or their mixts., acid addn. salts or quaternised prods.) are new. In (I) R3 = opt. branched 2-20C alkyl, halo- or Ph-substd. opt. branched alkyl, aryl (esp. Ph), halo- (esp. Cl)-substd. aryl (esp. p-halophenyl) or tolyl, R4 = lower alkyl (pref. Me, Et or Pr) or lower alkylene (pref. vinyl or propylene) and R5 and R6 = H or 1-3C alkyl or together form -(CH2)3-, -(CH2)4-, -CH=CH.CH=CH- or -CH=C(Me).C(Me)=CH-. Cpds. (I) are specifically claimed e.g. bis(N-methylimidazol -2-yl)nonylcarbinol. Prodn. of (I) by reacting 2 mols. of an imidazolyl-Li cpd. (or mixt. of such cpds. of the imidazolyl gps. in (I) are different) with 0.9-1.1 mols. of an ester of formula R3.COOR7 (R7 = 1-6C alkyl) and then hydrolysing the intermediate with a protonic cpd. esp. water. USE/ADVANTAGE - (I) are esp. useful in recovery of Pt gp. metals from aq. solns. or from used catalysts such as ammoxidn., reforming, isomerisation or car exhaust gas treating catalysts, cpd. (I) being contacted with the aq. soln. to effect selective pptn. or liq-liq. extn.