Abstract: A sample of a hydrocarbon oil containing asphaltenes is chromatographically analyzed by forming a mixture of the oil with a weak solvent. The mixture is passed in contact with a column of a stationary phase of fine solid particles of fully functionalized material, followed by a weak solvent. The solvent, after recovery from the column, is analyzed for aromatics by UV-absorption of UV radiation in the range 200 to 400 nm. The absorbance of the UV light by the irradiated eluents across the UV wavelength range is monitored and the integral of absorbance is derived as a function of photon energy across the wavelength range. The magnitude of the derived integral in at least one time interval corresponding with aromatics in the eluent from the stationary phase is measured as an indication of the level of aromatics in the oil sample. The weak solvent may be followed by a strong solvent which, in turn, may be followed by a strong solvent which is modified by the addition of a hydrogen bonding solvent.

Abstract: A sample of a hydrocarbon oil containing asphaltenes is chromatographically analyzed by forming a mixture of the oil with a weak solvent. The mixture is passed in contact with a column of a stationary phase of fine solid particles of fully functionalized material, followed by a weak solvent. The solvent, after recovery from the column, is analyzed for aromatics by UV-absorption of UV radiation in the range 200 to 400 nm. The absorbance of the UV light by the irradiated eluents across the UV wavelength range is monitored and the integral of absorbance is derived as a function of photon energy across the wavelength range. The magnitude of the derived integral in at least one time interval corresponding with aromatics in the eluent from the stationary phase is measured as an indication of the level of aromatics in the oil sample. The weak solvent may be followed by a strong solvent which, in turn, may be followed by a strong solvent which is modified by the addition of a hydrogen bonding solvent.

Abstract: An electrochemical device is described which has an oxygen electrode which contains a pyrochlore type electrocatalyst material. This electrocatalyst material is one or more electrically conductive pyrochlore compounds selected from the compounds of the following formula:A.sub.2 B.sub.2 O.sub.7-y (1)wherein A is any of the known pyrochlore structure metal cations, B is a pyrochlore structure metal cation at least a major portion of which is selected from the group consisting of one or more of Ru, Rh, Ir, Os, Pt, Ru-Pb mixtures and Ir-Pb mixtures, and wherein O.ltoreq.y.ltoreq.1.0. Desirably, A is a pyrochlore structure metal cation at least a major portion of which is selected from the group consisting of one or more of Pb, Bi and T1. A preferred group of pyrochlore compounds which are included in the above formula are those having the following formula:Pb.sub.2 [M.sub.2-x Pb.sub.x ]O.sub.7-y (2)wherein M is selected from the group consisting of Ru and Ir, wherein O.ltoreq.X.ltoreq.1.2 and O.ltoreq.y.ltoreq.1.

Abstract: Novel lead-rich pyrochlore type compounds are described having the formula:Pb.sub.2 [M.sub.2-x Pb.sub.x ]O.sub.7-ywherein M is selected from the group consisting of Ru, Ir and mixtures thereof and wherein x is greater than 0 and less than or equal to about 1.2 and y is greater than or equal to 0 and less than or equal to about 1.0. A method of synthesizing these compounds is also described. The method involves the solid state reaction of a lead source and a ruthenium source and/or an iridium source at temperatures below about 600.degree. C in an oxygen-containing environment.