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Current article is devoted to the development of a method for determining polymer functional additives and their molecular weight characteristics in diesel fuel by gel penetration chromatography. The objects of the study were solutions of “C5A”, “Maxoil D”, “Detersol”, polymethymethacrylate “D” (PMAD), “Keropur D ”, Antigel “Difron 3319” and “Superantigel” individual additives as well as the diesel fuel produced by the “Kuban Oil and Gas Company - Ilskiy Oil Refinery”, LLC. The conditions for chromatographic separation and determination of polymeric functional additives were determined considering the analyzed fuel matrix, the working range of the separated masses and molecular weights of analytes, and the composition of the eluent applicable for wide range of analytes. The chromatographic system was calibrated using the narrowly dispersed analytical standard polystyrene samples with molecular weights of 1000, 2000, 4000, 10000, 30,000, 50,000, and 70,000 Da respectively. The molecular weight characteristics were calculated for each functional additive from the analytical standard samples of polystyrene. The method of GPC determination of polymeric functional additives in diesel fuel, along with the concentration characteristics, also makes it possible to determine the molecular weight parameters of wide range of polymeric functional additives; therefore, it is promising for monitoring the quality of the diesel fuel. The proposed analytical scheme was tested in the analysis of real sample of diesel fuel. The GPC scheme for the determination of the “Keroflux 3699” depressant-dispersant additive in diesel fuel included sample preparation using the solid-phase extraction, calibration of the chromatographic system using the standard polystyrene samples, GPC determination of additive components, and the calculation of molecular weight characteristics. The molecular weight characteristics of the “Keroflux 3699” depressant dispersant additive in diesel fuel have been established - the number average and weight average molecular weights equivalent to polystyrene were 10,300 and 8800 Da respectively, and the polydispersity index of the additive was 1.17.

The features of methanol conversion using silica gel adsorbents modified with alumina, the result of which is the formation of dimethyl ether, are considered. The conversion of methanol to dimethyl ether on modified silica gel was studied in experimental and industrial plants in a wide temperature range and at various gas supply flows. There were obtained the dependences of the degree of conversion of methanol to dimethyl ether on the temperature of catalysis on modified samples of silica gel, the distribution of absorbed components in industrial adsorption plant for drying natural gas.

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