Nonaqueous conductometric titration of molybdenum with hexafluorosilicic acid, N,N-dimethyl-formamide adduct

Abstract

Nonaqueous conductometric titration of molybdenum in a lubricating oil was carried out by using N,N-dimethylformamide (DMF)-acid adduct as a titrant. The adduct was obtained by the reaction of hexafluorosilicic acid with DMF. Direct titration of ammonium molybdate with the adduct(H2SiF6-3DMF) in DMF was investigated by conductometric and photometric methods. The molar ratio of molybdenum(VI) and H2SiF6 at inflection points were found to be 2:1 and 1:1 by conductometric and 2:1 by photometric method, respectively. The reaction ratios were not influenced by water content of less than 1 percent. For an application of this method molybdenum in a lubricating oil was determined by the method after dissolving it in a mixture of DMSO-HNO3 and DMF-SO3 adducts. Molybdenum compound in organic substance soluble in organic solvents was found to be determined more rapidly by the proposed method as compared with the conventional method. © 1984, The Japan Society for Analytical Chemistry. All rights reserved.