Assessment of the sorption capacity and regeneration of carbon dioxide sorbents using thermogravimetric methods

Adsorption methods using solid sorbents are an alternative to the absorption technology in the processes of purification gases from carbon dioxide. There is a need to rapidly assess the suitability of sorbents for use it in PSA, TSA, or VPSA installations. Important parameters which determine the quality of the sorbent are the sorption capacity of sorbent, selectivity to CO₂ and the possibility of regeneration. This paper presents the results of sorption/desorption of CO₂ study on the impregnated porous materials using thermogravimetric methods. Thermogravimetry allows for rapid assessment of sorption capacity and regeneration of the sorbents. Specially selected temperature program allowed to determine the sorption capacity of sorbents depending on the concentration of CO₂ in the gas mixture and temperature. Degree of sorbent purification was determined in desorption process.     

Ferrocene‐Donor and 4,5‐Dicyanoimidazole‐Acceptor Moieties in Charge‐Transfer Chromophores with π Linkers Tailored for Second‐Order Nonlinear Optics

A series of new nonlinear optical chromophores ( 1 – 15 ) that were comprised of ferrocene‐donor and 4,5‐dicyanoimidazole‐acceptor moieties and various π linkers of different length were synthesized. Support for the presence of significant D ? A interactions in these NLO‐phores was obtained from the evaluation of the quinoid character of the 1,4‐phenylene moieties and their electronic absorption spectra, which featured intense high‐energy (HE) bands that were accompanied by less‐intense low‐energy (LE) bands. The redox behavior of these compounds was investigated by cyclic voltammetry (CV) and by rotating‐disc voltammetry (RDV); their electrochemical gaps decreased steadily from 2.64 to 2.09 V. In addition to the experimentally obtained data, DFT calculations of their absorption spectra, HOMO/LUMO levels, and second‐order polarizabilities (β) (?2ω,ω,ω) were performed. A structure–property relationship study that was performed by systematically altering the π linker revealed that the intramolecular charge‐transfer and nonlinear optical properties of these inorganic–organic hybrid D? π? A systems ( 1 – 15 ) were primarily affected by: 1) The presence of olefinic/acetylenic subunits; 2) the length of the π linker; and 3) the spatial arrangement (planarity) of the π linker.     

Studies on the catalysis of the reaction of organotin phenoxides with diethyl acetylenedicarboxylate

Different organotin phenoxides react at room temperature with diethyl acetylenedicarboxylate in diethyl ether, in the presence of lithium perchlorate to give a mixture of corresponding phenyl vinyl ethers and ring ethenylated phenols. Copyright © 2005 John Wiley & Sons, Ltd.     

Kinetics and mechanism of the reaction of allyl chloride with trichlorosilane catalyzed by carbon‐supported platinum

The kinetics of substrate conversions in the commercially important hydrosilylation of allyl chloride with trichlorosilane, catalyzed by active carbon‐supported platinum, as well as the yields of the main product (3‐chloropropyltrichlorosilane) and by‐products (tetrachlorosilane, propyltrichlorosilane) have been studied. On the basis of the measurements performed, the pseudo first‐order rate constants (k_obs, k₁ and k₂ from the model of competitive reactions) and activation energy (E_a = 11 kcal mol^?1 (46.2 kJ mol^?1)) were determined. The data obtained point to a non‐linear dependence of k_obs on the catalyst amount. From the kinetic relationships, the kinetic equation was deduced. All the results of kinetic, IR spectroscopic and thermogravimetric measurements, as well as the derived kinetic equation, have confirmed the general model of consecutive–competitive reaction involving the formation of a surface complex C₁ which can decompose in two directions according to the Chalk–Harrod mechanism. Copyright © 2003 John Wiley & Sons, Ltd.     

Martingales of Random Subsets of a Metric Space of Negative Curvature

We prove extension of classical convergence theorem of P. Lévy for martingales of random subsets of a metric space of negative curvature.     

Higgs boson production and weak boson structure

The influence of the QCD structure of the weak bosons on the Higgs boson production ine-p scattering is studied. The energy and Higgs boson mass dependence of the cross-section, following from the new contributions, is calculated. Work supported by the Polish State Committee for Scientifić Research (grant No. 2 P03B 081 09) and the Volkswagen-Stiftung