S. A. Volkov

Application of stationary phases in preparative-scale gas chromatography

Abstract Fluorosiloxane and arylenesiloxane polymers have been investigated as high-temperature siloxane phases in preparative gas chromatography. Their sorption capacities have been determined. Problems related to the vaporization of the sample and trapping of the separated fractions have also been investigated; these are of importance in high-temperature preparative chromatography. Examples are given of the use of siloxane rubbers as stationary phases for separating some mixtures on a preparative scale.

Multiple preparative chromatography. II. Dual-step system

SummaryThe capacity of dual-step preparative chromatographic separation systems is considered. It is shown that dualstep separation makes it possible to enhance the capacity of preparative installations as compared with single- and dual-stage purification of the compounds.

Design of and experience in operating technological preparative installations

Abstract Examples are given of the use of gas chromatography under industrial conditions for producing thiophene, indole and xylene on columns 500 and 1200 mm in diameter with annual capacities of from 100 to 1000 tons. Some problems associated with designing industrial columns are considered, including optimization of temperature conditions.

Investigation of the fluid dynamics of gas flow in large-diameter columns

Abstract The velocity field of a gas flow immediately above the packing surface of a chromatographic column loaded and compacted by various methods has been investigated using a laser anemometer.

Longitudinal spreading in gas and liquid chromatography and its connection with packed bed structure and the velocity of the mobile phase

Abstract Mobile phase velocity distributions were measured by laser Doppler anemometry at the outlet of chromatographic columns 46–140 cm in diameter. Large- and small-scale non-uniformities of the velocity field were detected; the influence of column diameter, packing particle size, mobile phase flow-rate and nature of the particle material on these non-uniformities was studied. The effect of velocity field non-uniformities on longitudinal spreading is discussed.

Chromatography in Fluidized Beds

SummaryChromatography is carried out under the conditions of fluidization, in long, straight tubes under organized and non-organized conditions. Under non-organized conditions the column is filled only with a sorbent. In organized conditions, either metal coils are added into the column or a segmented column is utilized with metal grids. The results obtained are compared to those obtained under fixed-bed conditions when the column is completely filled with the sorbent. Organized fluidized beds provide a significant decrease in longitudinal bandspreading.

A study of the shape of chromatographic bands in preparative gas chromatographic columns

Abstract In preparative gas chromatography it has been observed that the maximum flow-rate and concentration of a component occur in the centre of the column. The reasons for such phenomena are discussed. Some procedures for decreasing the HETP of large diameter columns are described.

Multiple preparative chromatography

SummaryThe capacity of different versions of single- and dual-stage separation of mixtures on a preparative scale is considered. It has been shown that dual-stage separation with intermediate condensation considerably enhances the capacity of the installation as compared with a single-stage process.