PHASE TRANSFER CATALYSED ORGANIC AND ORGANOMETALLIC SYNTHESES USING CARBONYL IRON COMPLEXES.

Phase transfer catalysts are useful in carrying out reactions when the reactants are present in (i) two immiscible liquid phases or (ii) solid-liquid phases. Among the versatile phase transfer catalysts (PTC), benzyltriethylammonium chloride, tricaprylmethylammonium chloride and several other quaternary ammonium salts are well known. The extractability of the ion pair O** plus X** minus into the organic phase increases with the number of -CH//2-groups. Several liquid reagents like DMF, DMA and hexamethylphosphoramide are also employed as PTC. The very costly crown ethers are only equally effective, like the cheap quaternary onium salts. But in special cases where the reaction is to be carried out in solid-liquid two-phase systems, crown ethers have special advantages. Cryptands can also be used effectively.