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Additional Reaction (additional + reaction)
Selected AbstractsChemisorption of carbon dioxide on sodium oxide promoted aluminaAICHE JOURNAL, Issue 11 2007K. B. Lee Abstract New equilibrium and column dynamic data for chemisorption of carbon dioxide from inert nitrogen at 250, 350, and 450°C were measured on a sample of sodium oxide promoted alumina, which was found to be a reversible chemisorbent for CO2. The equilibrium chemisorption isotherms were Langmuirian in the low pressure region (p <2.0 kPa) with a large gas,solid interaction parameter. The isotherms deviated from the Langmuirian behavior in the higher pressure region. A new analytical model which simultaneously accounted for Langmuirian chemisorption of CO2 on the adsorbent surface and additional reaction between the gaseous and sorbed CO2 molecules was used to describe the measured equilibrium data. The heats of CO2 chemisorption and the additional surface reaction were, respectively, 64.9 and 37.5 kJ/mol. The column breakthrough curves for CO2 sorption from inert N2 on the chemisorbent as well as the desorption of CO2 from the chemisorbent by N2 purge at 350°C could be described by the linear driving force (LDF) model in conjunction with the new sorption isotherm. The same LDF mass transfer coefficients can be used to describe both sorption and desorption processes. The CO2 mass transfer coefficients were (i) independent of feed gas CO2 concentration in the range of the data at a given temperature, and (ii) a weak function of temperature. The ratio of the mass transfer zone length to the column length was very small due to highly favorable CO2 sorption equilibrium. Several sequential cyclic CO2 sorption,desorption column dynamic tests were conducted to demonstrate the apparent stability of the material. © 2007 American Institute of Chemical Engineers AIChE J, 2007 [source] Rapid, Low-Temperature Synthesis of ,-SiC Nanowires from Si and GraphiteJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2010Hui-Ling Zhu ,-SiC nanowires were synthesized at a temperature as low as 150°C by the reaction of Si and graphite induced by an additional reaction between Na and S. Characterization by X-ray diffraction, high-resolution transmission electron microscopy, IR spectra, and Raman spectra demonstrates the formation of curly ,-SiC nanowires with several millimeters in length and 50,70 nm in diameter. Also, a prominent peak at 387 nm is observed in the visible photoluminescence emission. Besides the temperature, the molar ratio of S to Si (or graphite) has significant influence on the synthesis of SiC at relatively low temperatures. [source] Cell death and apoptosis-related proteins in muscle biopsies of sporadic amyotrophic lateral sclerosis and polyneuropathyMUSCLE AND NERVE, Issue 8 2001Benedikt G.H. Schoser MD Abstract To investigate disease-related differences of cell death and apoptosis in human denervation atrophy, we studied DNA fragmentation by the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) method in 38 biopsies of clinically nonaffected and affected muscles from patients with sporadic amyotrophic lateral sclerosis (sALS), in 13 muscle biopsies from patients with chronic peripheral neuropathies, and in 8 biopsies from control subjects. In addition, expression of apoptosis-related proteins, bax, bcl-2, and Fas, was studied in 20 biopsies of sALS and 10 chronic peripheral neuropathies. We identified DNA cleavage in 10% of myofibers of patients and in up to 1.5% of control samples. In clinically affected muscles of ALS, a larger amount of TUNEL-positive myofibers (mean 10.5 ± 5.9%) was detected, similar to chronic peripheral neuropathies (mean 10.0 ± 7.4%). Atrophic myofibers were immunopositive for bax, bcl-2, and, to a weaker extent, for Fas. However, bax-, bcl-2-, or Fas-positive atrophic myofibers did not reveal consecutive DNA cleavage. Differences between sALS subgroups and chronic peripheral neuropathies were not found. In human denervation atrophy the bcl-2/bax and the FasL/Fas systems are apparently active independently of DNA fragmentation and apoptosis. DNA fragmentation thus displays an additional reaction that is not disease-specific at chronic stages of human denervation processes, probably recapitulating events like skeletal muscle fiber remodeling in embryonic skeletal tissue development. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1083,1089, 2001 [source] Kharasch-Type Cyclizations of 2-Substituted Indole Derivatives Surprisingly Lead to SpiroindolesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 28 2010Sarah Van der Jeught Abstract Starting from 1H -indole-2-carboxylic acid, a series of spiro[2-oxoindole-pyrrolidines] could be synthesized in a straightforward manner. The key reaction is a Kharasch radical cyclization reaction of trichloroacetylated precursors. The identity of the tricyclic final products that were formed could be determined as spiro[2-oxoindole-pyrrolidines] by using a combination of different analytical techniques (1H NMR, 13C NMR, gHMBC, HRMS) and additional reactions. The produced skeletons are interesting from a medicinal point of view. [source] Thermal Degradation Kinetics of Nylon 66: Experimental Study and Comparison with Model PredictionsMACROMOLECULAR REACTION ENGINEERING, Issue 5 2007Mark A. Schaffer Abstract An experimental investigation of nonoxidative thermal degradation kinetics of nylon 66 melt under high temperature (280,300,°C) and low water content (0.02,0.14 wt.-%) conditions is presented. Experimental data for the time evolution of polymer end-group concentrations and degradation-product generation rates were compared with the predictions of the only published kinetic model. The omitted influence of water content is a plausible partial explanation for the considerable discrepancy between model predictions and some data. Several previously unreported or unquantified degradation products were identified and measured. Potential additional reactions to account for these results in future kinetic models are proposed. [source] | |||||||||||||