Combustion Of Ethyl Acetate Research Articles

Highly Active MnO2 for the Catalytic Combustion of Ethyl Acetate at Low Temperature

Highly Active MnO2 for the Catalytic Combustion of Ethyl Acetate at Low Temperature

Ce1−xSnxO2 Catalysts Prepared with Combustion Method for Catalytic Combustion of Ethyl Acetate

A series of Ce1−XSnXO2 (X = 0, 0.2, 0.3, 0.4, 0.5, 0.9, 1) catalysts were synthesized via the combustion method. The physical and chemical structures of the prepared catalysts were systematically characterized by XRD, BET, SEM, TEM, XPS, and TPR. The Ce1−XSnXO2 catalysts have higher catalytic activities than the mono-oxide catalysts, as there are synergistic effects between CeO2 and SnO2. The catalytic activities of the Ce1−XSnXO2 catalysts are dependent on the X for the catalytic combustion of ethyl acetate (EA). The Ce1−XSnXO2 (X < 0.5) catalysts show high catalytic performances. Meanwhile, the Ce0.8Sn0.2O2 and Ce0.7Sn0.3O2 catalysts display the highest catalytic performance, with T50 = 190 °C and T90 = 210 °C. More importantly, the Ce0.8Sn0.2O2 catalyst exhibits superior thermal and catalytic activity stability. It is found that the Ce1−XSnXO2 catalysts form solid solutions, as the X is <0.5. The reduction of Sn4+ species to Sn2+ is significantly promoted by the CeO2, which is an important factor attributed to the high catalytic activities of the solid solution Ce1−XSnXO2 catalysts. The catalytic activities of the Ce1−XSnXO2 catalysts exhibit a strong correlation to the surface atomic areas of Ce3+ and Oα (VO). In other words, the higher surface atomic areas of Ce3+ and Oα (VO) are, the higher the catalytic activities will have.

Influence of LaCoO3 perovskite oxides prepared by different method on the catalytic combustion of ethyl acetate in the presence of NO

Effect of preparation methods, including selective etching (LCO-E), sol–gel (LCO-S) and co-precipitation (LCO-C), on the physicochemical properties of LaCoO3 and its catalytic activity for removal ethyl acetate (EA) are investigated. The physicochemical properties of these LaCoO3 materials are characterized by XRD, N2 physicosorption, SEM, HR-TEM, H2-TPR O2-TPD, EPR and in situ DRIFTS. The preparation methods have a strong influence for LaCoO3 perovskites on crystalline size, surface area, redox ability, oxygen mobility, Co3+ content and the catalytic activity from the highest to the lowest value were LCO-E > LCO-S > LCO-C. In particular, we found that NO plays different roles in the reaction depending on the reaction temperature below or above 160 ℃, where the oxidation of NO to NO2 occurs or not. This directs a new strategy to simultaneously remove EA and NO, and even to pollutants with more complicated compositions. Moreover, it is found that the presence of small amount of water can significantly improve the reaction activity. The presence of excess water severely occupies the active sites, resulting in the decrease of activity. A mechanism for the removal of NO and EA in the presence of water is proposed.

Mechanistic Insight into Catalytic Combustion of Ethyl Acetate on Modified CeO2 Nanobelts: Hydrolysis-Oxidation Process and Shielding Effect of Acetates/Alcoholates.

In this study, based on the comparison of two counterparts [Mn- and Cr-modified CeO2 nanobelts (NBs)] with the opposite effects, some novel mechanistic insights into the ethyl acetate (EA) catalytic combustion over CeO2-based catalysts were proposed. The results demonstrated that EA catalytic combustion consisted of three primary processes: EA hydrolysis (C-O bond breakage), the oxidation of intermediate products, and the removal of surface acetates/alcoholates. Rapid EA hydrolysis typically occurs on surface acid/base sites or hydroxyl groups, and the removal of surface acetates/alcoholates resulting from EA hydrolysis is considered the rate-determining step. The deposited acetates/alcoholates like a shield covered the active sites (such as surface oxygen vacancies), and the enhanced mobility of the surface lattice oxygen as an oxidizing agent played a vital role in breaking through the shield and promoting the further hydrolysis-oxidation process. The Cr modification impeded the release of surface-activated lattice oxygen from the CeO2 NBs and induced the accumulation of acetates/alcoholates at a higher temperature due to the increased surface acidity/basicity. Conversely, the Mn-substituted CeO2 NBs with the higher lattice oxygen mobility effectively accelerated the in situ decomposition of acetates/alcoholates and facilitated the re-exposure of surface active sites. This study may contribute to a further mechanistic understanding into the catalytic oxidation of esters or other oxygenated volatile organic compounds over CeO2-based catalysts.

Silica-Supported Copper (II) Oxide Cluster via Ball Milling Method for Catalytic Combustion of Ethyl Acetate

Highly dispersed CuO/SiO2 catalysts were successfully synthesized by a green process of ball milling (BM) under solvent-free and room temperature conditions. The structural evolution of CuO/SiO2 catalysts prepared by BM was elucidated by TG-DSC, XRD, FT-IR, and XPS characterizations. We found that the copper acetate precursor was dispersed over the layer of copper phyllosilicate which was formed by reacting between the copper acetate precursor and the silica support during the BM process. The copper phyllosilicate layer over the support might play an important role in the stabilization of the CuO cluster (<2 nm) during thermal pretreatment. The 15% CuO/SiO2 catalyst exhibited the best catalytic activity for the catalytic combustion of ethyl acetate as it owned a highest active surface area of CuO among the CuO/SiO2 catalysts with different copper loadings.

Selective etching of in-situ formed La2O3 particles to prepare porous LaCoO3 perovskite for catalytic combustion of ethyl acetate

A selective etching method was reported to prepare porous LaCoO3 perovskite for catalytic combustion of ethyl acetate (EA). The porous LaCoO3 was obtained by selectively etching of in-situ formed La2O3 particles with acetic acid (HAc) from a pre-synthesized LaCoO3-La2O3 composite. XRD, N2 physisorption, ICP-OES, TEM, XPS, H2-TPR and O2-TPO showed that the etching of La2O3 with HAc not only generated surface La defects, but also improved the porosity, the exposure of active sites and the redox properties of the material. Therefore, the porous LaCoO3 can contact and activate the reactants efficiently, accelerating the reaction rate. LCO2.0-30, prepared with La/Co molar ratio of 2.0 and etched for 30 min, was the most active catalyst even in presence of H2O, with 100% EA conversion at 220 °C, due to its abundant porosity, surface active sites and strong reducibility. A possible reaction mechanism for EA combustion conducted on porous LaCoO3 perovskite was proposed.

Highly Active Mno2 for the Catalytic Combustion of Ethyl Acetate at Low Temperature

Highly Active Mno2 for the Catalytic Combustion of Ethyl Acetate at Low Temperature

Combustion of ethyl acetate: the experimental study of flame structure and validation of chemical kinetic mechanisms

Mole fraction profiles for reactants, major products, and main combustion intermediates were measured in near-stoichiometric and fuel-rich premixed burner-stabilized flames of ethyl acetate (AcOEt) under atmospheric pressure. Three recent chemical kinetic mechanisms for the AcOEt combustion were validated against the data reported. Their different predictive capabilities were explained using the results of kinetic analysis.

Catalytic oxidation of ethyl acetate over CuO/ZSM-5 catalysts: Effect of preparation method

Abstract A series of CuO/ZSM-5 catalysts with different copper loadings were prepared by impregnation (IM) and chemical vapor deposition (CVD) methods, respectively. Their physicochemical properties were investigated by N2 adsorption/desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectronic spectra (XPS), temperature-programmed reduction by hydrogen (H2-TPR) and temperature-programmed desorption of NH3 (NH3-TPD). The XRD and TEM results demonstrated that the crystallite size of the CuO prepared by CVD method was smaller than that by IM, and the XPS results illustrated that the copper specie was mostly in Cu2+ state and Cu+ co-existed. The performance of catalytic oxidation of ethyl acetate was conducted in the fixed-bed reactor based on CuO/ZSM-5 catalysts. The experimental results showed that the preparation method affected the catalytic activity of CuO/ZSM-5; the CVD catalysts exhibited a higher catalytic activity for ethyl acetate oxidation compared with the IM catalysts at the same copper loadings. Ethanol and acetaldehyde are observed to be the intermediate products in the combustion of ethyl acetate over the synthesized catalysts. The relative amounts of acetaldehyde and ethanol are determined by the selectivity of the catalyst toward acetaldehyde production from ethanol. Particularly, the 3 wt% CVD catalyst showed the best catalytic activity for ethyl acetate oxidation with 90% conversion of ethyl acetate at 235 °C, which was much lower than that of the 3 wt% IM catalyst (278 °C), meanwhile, the intermediate products of the 3 wt% CVD for ethyl acetate oxidation were completely oxidized into CO2 and H2O at temperature as low as 288 °C.

OXIDATION OF ETHYL ACETATE ON Fe-Mn OXIDES FROM NITRATES DEPOSITED BY IMPREGNATION ON MONOLITHS OF AISI 304 STAINLESS STEEL

The iron-manganese mixed monolithic catalysts were obtained by impregnation from nitrates as precursors. A monolithic support was studied with and without alumina as surface generator. The characterization consisted in XRD, SEM, Adherence test, SBET and TPR. The monolith was evaluated in the combustion of ethyl acetate. The preparation method was very satisfactory in terms of reproducibility and adherence of the deposited phase. The higher activity of IFeMnx with respect to Al3FeMnx may be attributed for the formation of the solid solution where the Fe is introduced to the bixbyite structure. However, the presence of defective MnOx species in monoliths without alumina which might help to improve their performance is observed.

Study of Deactivation and Regeneration of ZSM-5 Supported Manganese Nano Catalysts in Combustion of Ethyl Acetate and 2-Propanol

Study of Deactivation and Regeneration of ZSM-5 Supported Manganese Nano Catalysts in Combustion of Ethyl Acetate and 2-Propanol

A novel glass fiber catalyst for the catalytic combustion of ethyl acetate

Supported CuO catalysts were prepared by wet impregnation into novel glass fiber corrugated honeycomb supports, and the catalytic combustion of ethyl acetate and the effect of copper loading were examined. Among the catalysts tested, Cu10/Al2O3-M showed the highest activity. For the catalyst, 100% conversion of ethyl acetate was achieved at 300°C, feed concentration of 1802mg/m3 and the space velocity of 5000h−1. To reveal these phenomena, the supports and catalysts were characterized by SEM, BET, XRD, H2-TPR and ethyl acetate-TPD. The catalyst activity was strongly related to the amount of highly dispersed CuO species and suitable porosity.

Catalytic Combustion of Ethyl Acetate over Manganese Oxides Deposited on Metallic Monoliths

AbstractMnOx/AISI 304 austenitic stainless‐steel monolithic catalysts were prepared by impregnation with aqueous solutions of manganese nitrate or acetate. The preparation method was satisfactory in terms of reproducibility and adherence of the deposited phase. The use of different precursors led to significantly dissimilar results. With manganese nitrate, the formation of Mn‐Cr‐O mixed phases on the surface was favored, whereas with manganese acetate, Mn2O3 was the predominant active phase. The Mn‐Cr‐O mixed phases would be highly dispersed but their catalytic activity was low. The major catalytic behavior was obtained with monoliths impregnated with manganese acetate.

MnCu/cordierite monolith used for catalytic combustion of Volatile Organic Compounds

AbstractA MnCu‐mixed oxide catalyst supported on a cordierite monolith was synthesized. The catalyst showed very good stability and high homogeneity and presented an excellent catalytic activity in the combustion of ethyl acetate, n‐hexane, and its mixture. The total conversion temperature of the mixture was determined by the temperature at which the most difficult molecule was oxidized.

Catalytic combustion of ethyl acetate over CeMnO x and CeMnZrO x compounds synthesized by coprecipitation method

Ce 0.6Mno. 4O2 catalysts with different sources of manganese and Ce 0.6-xZroe ZrMno. 4O 2 mixed oxide catalysts were prepared by coprecipitation method and were characterized by N 2 adsorption-desorption, TPR, XRD, and XPS techniques. The activities of the prepared catalysts for ethyl acetate combustion, and the effects of calcination temperature and space velocity on catalytic activity were investigated. The results showed that partial replacement of Mn(NO 3) 2 with KM11O4 as sources of manganese could improve activities of catalysts. Ce 0.45Zr o. 15Mno.4O2} catalyst exhibited the best catalytic activity and high thermal stability, e.g., Γ90 could be still below 210 °C even if space velocity was up to 20000 h −1.

Preparation of MnO x /AISI 304 Austenitic Stainless Steel Monoliths for Catalytic Combustion of Ethyl Acetate

The objective of this study is to explore the treatment conditions of austenitic stainless steel, AISI 304, for catalytic devices used in volatile organic compounds (VOCs) combustion. The variables studied were treatment exposure time, temperature and atmosphere. AISI 304 steel surface resulted in different morphologies depending on temperature and atmosphere. The oxide layer was com- posed of mixed oxides of Cr-Fe and Cr-Mn-Fe, forming octahedral and hexagonal crystals. The addition of man- ganese with the objective of reaching the ideal Mn/Fe ratio improved notably the catalytic performance.

Kinetic study of the combustion of ethanol and ethyl acetate mixtures over a MnCu catalyst

A kinetic study of ethanol and ethyl acetate combustion on an efficient catalyst identified as Mn9Cu1 is reported in this contribution. Ethanol and ethyl acetate are typical VOCs which can be found in effluents of printing industries. Ethanol oxidation produces an intermediate product, acetaldehyde. On the other hand, ethyl acetate oxidation produces directly CO2 and H2O. Acetaldehyde reacts more slowly than ethanol, while ethyl acetate is slightly more difficult to oxidize than acetaldehyde.Strong inhibition effects among the species involved (ethanol, ethyl acetate and acetaldehyde) should be explicitly considered to propose reaction rate expressions. Thus, experimental data were satisfactorily fitted employing LHHW type expressions. The estimated activation energy of ethyl acetate and ethanol oxidation lies in the range of values reported in the literature for similar catalysts.

Preparation of Ag–M (M: Fe, Co and Mn)–ZSM‐5 bimetal catalysts with high performance for catalytic oxidation of ethyl acetate

The catalytic combustion of ethyl acetate has been investigated in a series of mono‐metal silver and bimetal Ag–M (M: Fe, Co and Mn)‐modified HZSM‐5 zeolites. The objective was to find a catalyst with high superior activity, selectivity towards deep oxidation product and stability. The catalyst activity was measured under excess oxygen condition in a fixed bed reactor operated at gas hourly space velocity (GHSV) = 30000 h−1, reaction temperature between 150 and 450°C and ethyl acetate inlet concentration of 1000 ppm. Both Fe–Ag–ZSM‐5 and Co–Ag–ZSM‐5 catalysts exhibited high activity in the oxidation of ethyl acetate. The sequences of catalytic activity and catalytic stability were as follows: Fe–Ag–ZSM‐5 > Co–Ag–ZSM‐5 > Mn–Ag–ZSM‐5 > Ag–ZSM‐5 > HZSM‐5. Total conversion of ethyl acetate was achieved at above 250°C. The catalysts were characterized by inductively coupled plasma atomic emission spectroscopy, X‐ray diffraction, transmission electron microscopy, scanning electron microscopy and X‐ray photoelectron spectroscopy.

EFFECTS OF FEED CONCENTRATION AND WATER VAPOR ON CATALYTIC COMBUSTION OF ETHYL ACETATE AND BENZENE IN AIR OVER CR-ZSM-5 CATALYST

Catalytic combustion of ethyl acetate (EAc) and benzene (Bz) over chromium exchanged ZSM-5 (Si/Al=240) is reported. An 11 mm i.d. fixed-bed catalytic reactor, operated at temperatures between 100 oC and 500 oC, and under excess oxygen condition, was used for the catalytic activity measurement. Apparent order of reaction and apparent activation energy were determined by operating the reactor differentially at a gas hourly space velocity (GHSV) of 78,900 h-1 and feed concentrations between 3,500 ppm to 17,700 ppm and 3,700 to 12,400 ppm for ethyl acetate and benzene, respectively. Ethyl acetate was more reactive than benzene due to highly reactive carbonyl group in the molecule. The combustion process satisfactorily fitted pseudo first-order kinetics with respect to organic concentration and a zero-order dependence on the oxygen concentration. The presence of water vapor (9,000 ppm) in the feed stream was found to weaken the reactivity of these organics which could also be demonstrated with increases in the activation energy from 23.1 kJ/mole to 37.6 kJ/mole for ethyl acetate and from 27.6 kJ/mole to 46.1 kJ/mole for benzene. Water vapor was found to play a positive role in the formation of carbon dioxide yield in ethyl acetate combustion. Deactivation of catalyst by water appeared to be only temporary and the activity reverted back to its original value once the source of water vapor was removed.

Copper and chromium oxide nanocomposites supported on SBA-15 silica as catalysts for ethylacetate combustion: Effect of mesoporous structure and metal oxide composition

Copper and chromium oxide nanocomposite materials with different Cu/Cr ratio are prepared by deposition on silica host matrices with different textural properties and characterized by XRD, nitrogen physisorption, UV–Vis, FTIR, XPS and TPR-TG. Their catalytic behavior in ethylacetate total oxidation was also studied. A complex effect of Cu/Cr ratio, textural characteristics of the support and reaction medium on the phase composition of the supported active phase was found. Different mechanisms of regulation of loaded metal oxides dispersion depending on the support peculiarities were discussed. The relation between the phase composition and the catalytic properties of various bi-component materials was studied.