6145-18-2Relevant academic research and scientific papers
Mechanistic Insights into Catalytic Ethanol Steam Reforming Using Isotope-Labeled Reactants
Crowley, Stephen,Castaldi, Marco J.
supporting information, p. 10650 - 10655 (2016/09/03)
The low-temperature ethanol steam reforming (ESR) reaction mechanism over a supported Rh/Pt catalyst has been investigated using isotope-labeled EtOH and H2O. Through strategic isotope labeling, all nonhydrogen atoms were distinct from one another, and allowed an unprecedented level of understanding of the dominant reaction pathways. All combinations of isotope- and non-isotope-labeled atoms were detected in the products, thus there are multiple pathways involved in H2, CO, CO2, CH4, C2H4, and C2H6product formation. Both the recombination of C species on the surface of the catalyst and preservation of the C?C bond within ethanol are responsible for C2product formation. Ethylene is not detected until conversion drops below 100 % at t=1.25 h. Also, quantitatively, 57 % of the observed ethylene is formed directly through ethanol dehydration. Finally there is clear evidence to show that oxygen in the SiO2-ZrO2support constitutes 10 % of the CO formed during the reaction.
Comparative study of MTO conversion over SAPO-34, H-ZSM-5 and H-ZSM-22: Correlating catalytic performance and reaction mechanism to zeolite topology
Li, Jinzhe,Wei, Yingxu,Liu, Guangyu,Qi, Yue,Tian, Peng,Li, Bing,He, Yanli,Liu, Zhongmin
experimental part, p. 221 - 228 (2011/11/05)
Conversion of methanol to olefins (MTO) was comparatively studied over three zeolites with different topologies, i.e. SAPO-34, H-ZSM-5 and H-ZSM-22. The correlation between reaction mechanism and the zeolite topology was also investigated. SAPO-34 presented the highest selectivity for light olefins such as ethene and propene, and no aromatics were detected. H-ZSM-5 showed relatively high selectivity for ethene and propene, and large amount of aromatics were detected. Over H-ZSM-22, the selectivity for ethene is very low and a large amount of non-aromatic C6+ olefins generated. With the aid of 12C-methanol/13C-methanol switch technique, the reaction routes followed by methanol conversion over the three catalysts could be distinguished. The reaction mechanisms, which varied with the zeolite topologies, caused the differences in catalytic performances. The co-reaction of 13C-methanol with 12C-olefin or 12C-aromatic, were carried out for further clarification of the operation of the different catalytic cycles in methanol conversion.
Photocatalytic Oxidation of Ethanol: Isotopic Labeling and Transient Reaction
Muggli, Darrin S.,Larson, Sheldon A.,Falconer, John L.
, p. 15886 - 15889 (2007/10/03)
Transient reaction techniques were combined with isotope labeling to study the reaction steps for the room-temperature, photocatalytic oxidation (PCO) of ethanol on TiO2.Carbon-13 labeled ethanol (CH3(13)CH2OH) was adsorbed on the catalyst and photocatalytically oxidized in the absence of gas-phase ethanol.The amounts of species remaining on the surface after PCO were determined by temperature-programmed oxidation.During PCO, only CO2 and H2O formed for low coverages of ethanol, whereas acetaldehyde also desorbed for saturation coverage.Acetaldehyde forms rapidly from ethanol oxidation during PCO.At both low and high ethanol coverages, the α-carbon is preferentially oxidized and thus (13)CO2 forms faster than (12)CO2 at short illumination times.At longer times, the rates of (13)CO2 and (12)CO2 formation are nearly identical.The difference in behavior between (13)CO2 and (12)CO2 formation suggests two parallel reactions of ethanol, which may be due to two adsorption sites on TiO2.
Cracking of (5-(13)C)-n-Nonane with Quartz Wool, Silica-Alumina and Type Y Zeolite
Weeks, Thomas J.,Ladd, Irwin R.,Bolton, Anthony P.
, p. 84 - 91 (2007/10/02)
The cracking mechanism of (5-(13)C)-n-nonane has been studied over quartz wool, silica-alumina and a type Y zeolite.The products observed at a reaction temperature of 510 deg C over quartz wool agree reasonably well with the currently accepted mechanism of free radical cracking.Reaction with silica-alumina at 500 deg C and zeolite at 230 deg C results in a (13)C labelled product distribution which agrees with neither a thermal cracking mechanism nor the currently accepted mechanism of β-scission of carbonium ion intermediates.Rather, the data suggest that the product distribution is a result of the temperature-dependent random description and cracking of a complex polymeric precursor.
