NEW PARAMAGNETIC RELAXATION REAGENT FOR WATER-IN-OIL EMULSIONS

The gadolinium(III) beta-diketonate complexes and their adducts with n eutral ligands such as triphenylphosphine oxide (TPPO), trioctylphosph ine oxide (TOPO), hexamethylphosphoramide (HMPA), and dimethyl sulfoxi de (DMSO) have been synthesized and examined as paramagnetic relaxatio n reagents in analysis of water-in-oil emulsions by the nuclear magnet ic relaxation method. For all compounds the solubility in water and n- hexane has been determined. The dipivaloylmethanate complex Gd(DPM)(3) .TOPO (I) was found to show the best solubility in n-hexane (0.05 mol/ l) as well as practical insolubility in water. When added to a sample of hydrocarbons (n-hexane, benzene, kerosene, oil), (I) caused a gener al enhancement of spin-lattice relaxation rates of both aromatic and a liphatic protons. In the study of kerosene-water and oil-water emulsio ns, the addition of 0.05% (I) was associated with shorter organic prot on relaxation times than those of water protons and hence the relaxati on curves might be successfully resolved into two components. The resu lts presented demonstrate that (I) can be used as a paramagnetic relax ation reagent to determine components in water-in-oil emulsions.