Aromatic hydrocarbons, adsorption

Jaynes WF, Boyd SA (1991b). Hydrophobicity of siloxane surfaces in smectites as revealed by aromatic hydrocarbon adsorption from water. Clays Clay Miner 39 428-436... 

If, for the purpose of comparison of substrate reactivities, we use the method of competitive reactions we are faced with the problem of whether the reactivities in a certain series of reactants (i.e. selectivities) should be characterized by the ratio of their rates measured separately [relations (12) and (13)], or whether they should be expressed by the rates measured during simultaneous transformation of two compounds which thus compete in adsorption for the free surface of the catalyst [relations (14) and (15)]. How these two definitions of reactivity may differ from one another will be shown later by the example of competitive hydrogenation of alkylphenols (Section IV.E, p. 42). This may also be demonstrated by the classical example of hydrogenation of aromatic hydrocarbons on Raney nickel (48). In this case, the constants obtained by separate measurements of reaction rates for individual compounds lead to the reactivity order which is different from the order found on the basis of factor S, determined by the method of competitive reactions (Table II). Other examples of the change of reactivity, which may even result in the selective reaction of a strongly adsorbed reactant in competitive reactions (49, 50) have already been discussed (see p. 12). 

Oscik and Chojnacka [63] use TEC adsorption in the investigation of six aromatic hydrocarbons (naphthalene, diphenyl, anthracene, pyrene, chrysene, and acenaphthene) on silica gel G by elution with different binary mobile phases (trichloroethylene-benzene, carbon tetrachloride-benzene, n-heptane-trichloroethylene. 

Membranes offer a format for interaction of an analyte with a stationary phase alternative to the familiar column. For certain kinds of separations, particularly preparative separations involving strong adsorption, the membrane format is extremely useful. A 5 x 4 mm hollow-fiber membrane layered with the protein bovine serum albumin was used for the chiral separation of the amino acid tryptophan, with a separation factor of up to 6.6.62 Diethey-laminoethyl-derivatized membrane disks were used for high-speed ion exchange separations of oligonucleotides.63 Sulfonated membranes were used for peptide separations, and reversed-phase separations of peptides, steroids, and aromatic hydrocarbons were accomplished on C18-derivatized membranes. 

Szabo, G., Guczi, J., Bulman, R.A. (1995) Examination of silica-salicylic acid and silica-8-hydroxyquinoline HPLC stationary phases for estimation of the adsorption coefficient of soil for some aromatic hydrocarbons. Chemosphere 30, 1717-1727. 

Dachs, J., Eisenreich, S.J. (2000) Adsorption onto aerosol soot carbon dominates gas-particle partitioning of polycyclic aromatic hydrocarbons. Environ. Sci. Technol. 34, 3690-3697. 

Gridin, V.V., Litani-Barzilai, I., Kadosh, M., Schechter, I. (1998) Determination of aqueous solubility and surface adsorption of polycyclic aromatic hydrocarbons by laser multiphoton ionization. Anal. Chem. 70, 2685-2692. 

Walters, R.W., Luthy, R.G. (1984) Equilibrium adsorption of polycyclic aromatic hydrocarbons from water onto activated carbon. Environ. Sci. Technol. 18(6), 395-403. 

Yamasaki, H., Kuwata, K., Kuge, Y. (1984) Determination of vapor pressure of polycyclic aromatic hydrocarbons in the supercooled liquid phase and their adsorption on airborne particulate matter. Nippon Kagaka Kaish. 8, 1324—1329. 

Storing aqueous samples in glass containers prior to being examined for polynuclear aromatic hydrocarbons at the ng 1 1 level can also be a problem. There is evidence of adsorption of the hydrocarbons onto the glass surface. This problem is considerably reduced by putting the extracting solvent in the bottle before introducing the water sample. 

A fundamental improvement in the facilities for studying electrode processes of reactive intermediates was the purification technique of Parker and Hammerich [8, 9]. They used neutral, highly activated alumina suspended in the solvent-electrolyte system as a scavenger of spurious impurities. Thus, it was possible to generate a large number of dianions of aromatic hydrocarbons in common electrolytic solvents containing tetraalkylammonium ions. It was the first time that such dianions were stable in the timescale of slow-sweep voltammetry. As the presence of alumina in the solvent-electrolyte systems may produce adsorption effects at the electrode, or in some cases chemisorption and decomposition of the electroactive species, Kiesele constructed a new electrochemical cell with an integrated alumina column [29]. 

Tables VI and VIII contain in parentheses several sets of adsorption coefficients of aromatic hydrocarbons that have been estimated from competitive experiments or adsorption measurements. The problems with the interpretation have been mentioned in Section V,A,2. Other series that have been correlated with Type A and Type B expressions are summarized in Table IX 48, 52, 74, 82, 96,100,103,156-159). The series showing parallel...

Kulprathipanja, S. (1995) Process for adsorptive separation of ethylbenzene from aromatic hydrocarbons. U.S. Patent 5,453,550. 

Neuzil, R. (1971) Aromatic hydrocarbon separation by adsorption. US Patent 3,558,730. 

This chapter reviews the adsorptive separations of various classes of non-aromatic hydrocarbons. It covers three different normal paraffin molecular weight separations from feedstocks that range from naphtha to kerosene, the separation of mono-methyl paraffins from kerosene and the separation of mono-olefins both from a mixed C4 stream and from a kerosene stream. In addition, we also review the separation of olefins from a C10-16 stream and review simple carbohydrate separations and various acid separations. 

The second part of the book covers zeolite adsorptive separation, adsorption mechanisms, zeolite membranes and mixed matrix membranes in Chapters 5-11. Chapter 5 summarizes the literature and reports adsorptive separation work on specific separation applications organized around the types of molecular species being separated. A series of tables provide groupings for (i) aromatics and derivatives, (ii) non-aromatic hydrocarbons, (iii) carbohydrates and organic acids, (iv) fine chemical and pharmaceuticals, (v) trace impurities removed from bulk materials. Zeolite adsorptive separation mechanisms are theorized in Chapter 6. 

Chapter 7 gives a review of the technology and applications of zeolites in liquid adsorptive separation of petrochemical aromatic hydrocarbons. The application of zeolites to petrochemical aromatic production may be the area where zeolites have had their largest positive economic impact, accounting for the production of tens of millions of tonnes of high-value aromatic petrochemicals annually. The nonaromatic hydrocarbon liquid phase adsorption review in Chapter 8 contains both general process concepts as well as sufficient individual process details for one to understand both commercially practiced and academic non-aromatic separations. 

Eiceman, G.A. and Vandiver, VJ. Adsorption of polycyclic aromatic hydrocarbons on fly ash from a municipal incinerator and a coal-fired power plant, Atmos. Environ., 17(3) 461-465, 1983. 

El-Dib, M.A. and Badawy, M.l. Adsorption of solnble aromatic hydrocarbons on grannlar activated carbon, Water Res., 13(3) 255-258, 1979. 

Sterling Jr MC, Bonner JS, Page CA, Ernest ANS, Autenrieth RL (2003) Partitioning of crude oil polycyclic aromatic hydrocarbons in aquatic systems. Environ Sci Technol 37 4429-4434 Stern O (1924) Zur theorie der elecktrolytischen doppelschict. Z Electrochem 30 508-516 Stollenwerk KC, Grove DB (1985) Adsorption and desorption of hexavalent chromium in an alluvial aquifer near Telluride, Colorado. J Environ Qual 14 150-155 Stumm W, Morgan JJ (1996) Aquatic chemistry, 3rd edn. WUey, New York... 

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