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Thermal decomposition of 1-(ferrocenyl)ethanol was carried out under N2 and O2 atmospheres. Peak deconvolution method was used to separate the overlapped peaks and hence to obtain the temperature range of individual reactions. The decomposition followed two steps for N2 atmosphere while for O2 atmosphere three steps were observed. The integral iso-conversional methods (FWO, KAS, Tang, Starink, Vyazovkin and Akbi) were used to estimate the activation energy. The activation energies estimated are comparatively higher for FWO method in comparison to other methods while that estimated following other methods are quite close. Step-wise reaction mechanism functions have been determined. Simulated conversion plots were compared with the experimentally observed plots, and their close agreement implied the accuracy of the kinetic method adopted for analysis. Utilising the estimated kinetic parameters, thermodynamic parameters (ΔS, ΔH and ΔG) were calculated. All estimated kinetic and thermodynamic parameters indicate the strong influence of gaseous medium used for solid state thermal decomposition. Thermally decomposed materials were characterized with powder XRD, SEM and EDX studies. From the characterization results it was concluded that thermal decomposition of 1-(ferrocenyl)ethanol led to the formation of nanocrystalline iron oxides only in oxidative atmosphere. It was proposed that at the initial state of decomposition magnetite might have formed as an intermediate which with increase of temperature first converted to maghemite and then gradually to hematite. The present study, through kinetic analysis and characterization of the decomposed materials, convincingly establishes the significant effect of the reaction atmosphere on the thermal decomposition of an organo-iron compound as well as the nature of the material produced. [ABSTRACT FROM AUTHOR]

This study investigates the kinetics data of glass wool (GW) and extruded polystyrene (XPS) insulation materials used in cladding systems using a systematic framework. The determination of appropriate kinetic properties, such as pre-exponential factors, activation energy and reaction orders, is crucial for accurately modelling the full-scale fire performance of insulation materials. The primary objective of this research is to extract thermal and kinetics data of XPS and GW insulation materials employed in high-rise buildings. To obtain these properties, thermogravimetric analysis (TGA) is conducted at four different heating rates: 5, 10, 15 and 20 K/min. The TGA results serve as the basis for determining the kinetic properties using a combination of model-free and model-based methods. The outcomes of this study are expected to be highly beneficial in defining the pyrolysis reaction steps and extracting kinetics data for fire modelling of such insulation materials. This information will enhance the understanding of the fire behaviour and performance of these materials during fire incidents, aiding in developing more accurate fire models and improving fire safety strategies for cladding systems in high-rise buildings. [ABSTRACT FROM AUTHOR]

Pd-only three-way catalysts with improved catalytic activity for NO elimination were prepared. In order to explore the catalytic reaction rules of NO reduction under a three-way catalytic system, a series of single reactions related to NO reduction were evaluated. It was found that the reaction temperatures of NO + H2 or NO + CO or NO + C3H6 reactions were below 250 °C, while that of NO + C3H8 was up to 350 °C. Thus, the reaction NO + C3H8 served as the key reaction in determining the purification efficiency of NO at the high-temperature stage. By in situ FTIR, we proposed that three possible steps were involved in NO + C3H8 reaction. The first step was the oxidation of C3H8 and NO to acetone and nitrate species by active oxygen species, respectively (C3H8 + O* → C3H6O, NO + O* → NO3−). XPS results revealed that the amount of active oxygen species in Pd/CeO2-ZrO2-Al2O3 (Pd/CZA, 73.7%) was much higher than that in Pd/CexZr1−xO2+Al2O3 (Pd/CZ+A, 64.1%). This was in line with the higher reaction efficiency of the first step over Pd/CZA. Then the NO + C3H8 reaction was accelerated by the first step, which consequently contributed to the higher NO elimination efficiency of Pd/CZA. [ABSTRACT FROM AUTHOR]

Deuterium isotope exchange was employed to investigate some of the reaction steps for the hydrodechlorination of CF3CFHCl and CH3CH2Cl on supported Pd catalysts. Hydrodechlorination rates for both compounds using D2 or H2 were identical. It is concluded that H or D species are not involved in the rate-determining step of the hydrodechlorination reaction. Experiments using a combined H2 and D2 feed for hydrodechlorination of CF3CFHCl showed that CF3CFH2 was preferentially formed over CF3CFHD. This experimental observation can be explained by isotope effects and is consistent with gas phase H2 in equilibrium with adsorbed H and a reaction step consisting of the combination of surface adsorbed CF3CFH&z.sbnd; species with adsorbed H. Deuterated product distributions of CF3CFHCl and CH3CH2Cl hydrodechlorination experiments with D2 were analyzed to explore the reaction steps beyond the kinetically relevant steps. The main product of CF3CFHCl hydrodechlorination was CF3CFHD, showing that the C&z.sbnd;Cl bond is preferentially broken. In the case of CH3CH2Cl, substantial C&z.sbnd;H bond breaking accompanies the initial C&z.sbnd;Cl scission. Deuterium exchange experiments with ethane on Pd/C and Pd/ZrO2 were also investigated and the results indicate that the CH3CH2Cl product distribution is not caused by re-adsorption and subsequent exchange reaction of ethane. [Copyright &y& Elsevier]

Intensive and broad studies of chemical reactions concerning X(NSO)2 (X=Se, Te), X2Te(NSO)2 (X=F, Cl, Br) and X′2Te(NSC)2X′2 (X′=F, Cl) provides besides new interesting compounds also valuable intermediates for a better understanding of reaction pathways in chalcogen–nitrogen chemistry. Based on the mechanism elucidated for the formation of [SeSeNSN+]2[MF6−]2 or [ClSeSeNSN][SbCl6−] from Se(NSO)2 and MF5 (M=As, Sb, Nb) or Se(NSO)2 and SbCl5 respectively an interpretation of the reaction sequences of other procedure such as Te(NSO)2+SbCl5 or e.g. Cl2Te(NSO)2 with MCl3 (M=Ga, Al, Fe) could be provided. It was proved that a desulfurisation process is responsible for transforming Cl2Te(NSO)2 and derivated products in the presence of MCl3 into [(Cl2Te)2N+][MCl4−] and [ClTeSNSN+][MCl4−]. The results gained in these studies led directly to the synthesis of [SSNNN+][TeCl5−], the first ring with three cummulated nitrogen atoms. In order to learn more about the possible structures of Cl2Te(NSN)2TeCl2, careful and intensive investigations proved the formation of the cage N[Te(Cl)NSN]3. A thorough reinvestigation of the original synthesis of the cage yielded S4N4 as an additional product and by varying the stoichiometry between the educts TeCl4 and (CH3)3SiNSNSi(CH3)3 important intermediates could be detected and isolated. They provided the base for understanding the consecutive steps during the procedure between educts and to yield products. Fluorine substituted acyclic, cyclic, neutral and ionic chalcogen–nitrogen compounds are described as well as relationship among themselves and related compounds. Interesting and valuable correlations are presented and evaluated. [Copyright &y& Elsevier]