Combustion Of Ethyl Acetate Research Articles

Preparation and characterizations of Ce-Cu-O monolithic catalysts for ethyl acetate catalytic combustion

Ce-Cu-O monolithic catalysts were prepared by using Ce 0.9Cu 0.1O 1.9 solid solution or nitrate as precursors, and their catalytic performance for the combustion of ethyl acetate were studied. The catalysts calcined at a low temperature showed high catalytic activities. When calcined at high temperatures, the catalyst with Ce 0.9Cu 0.1O 1.9 solid solution as precursor remained a high activity, while the catalyst with metal nitrates as precursors exhibited a suppressed reactivity. Therefore, the catalyst prepared with the Ce 0.9Cu 0.1O 1.9 solid solution had better thermal stability.

Activation of Pt/SnO 2 catalyst for catalytic oxidation of volatile organic compounds

The catalytic combustion of toluene over tin oxide-supported metal catalysts (Pt/SnO 2, Pd/SnO 2, Ru/SnO 2, and Rh/SnO 2) was studied. As a result, the Pt/SnO 2 catalyst exhibited the highest activity. The activity of Pt/SnO 2 catalyst is expected to originate from the strong chemical interaction between platinum and tin oxide. The correlation between the nano-structure and catalytic activity in the oxidation of ethyl acetate was investigated for the Pt/SnO 2 catalysts treated under a reducing or an oxidative atmosphere. For the transmission electron microscopy image of the as-calcined Pt/SnO 2 catalyst, the fine particles composed of platinum species was highly dispersed on the surface of SnO 2 support. After the reduction treatment at 400 °C, the peculiar core–shell structure was formed. It is noted that the particles with this structure disappeared by the reoxidation treatment in air, and the redispersion of nano-particles was confirmed. The particles with the core–shell structure were observed again after the second reduction treatment for the reoxidized catalyst. The catalytic activities of ethyl acetate combustion over Pt/SnO 2 catalysts were deteriorated and activated, corresponding to the nano-structural changes induced by the reduction–oxidation treatments.

Catalytic combustion of ethyl acetate and nano-structural changes of ruthenium catalysts supported on tin oxide

Correlation between the catalytic activity and the nano-structure of ruthenium catalyst supported on tin oxide was investigated. As-calcined Ru/SnO2 catalyst exhibited high catalytic activity for ethyl acetate combustion despite its low surface area of ca. 5.0m2g−1. The catalytic activity was degraded by the reduction treatment at 400°C, whereas it was partially restored by the subsequent reoxidation treatment at 400°C. To elucidate the variation in the catalytic activity, the ruthenium catalysts heat-treated under reductive or oxidative condition were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). In the as-calcined catalyst, it was revealed that the fine particles with the small contact angles were well-dispersed on the surface of tin oxide support. In the deactivated catalyst treated at 400°C under a reductive atmosphere, the large particles of intermetallic compounds with the core–shell structure were clearly observed. On the other hand, upon the reoxidation treatment at 400°C the particles with the core–shell structure disappeared accompanied with the appearance of the nano-sized particles. Accordingly, it was clarified that the catalytic activity was strongly influenced by the structural changes of active sites such as sintering and redispersion.

Low-Temperature Complete Oxidation of Ethyl Acetate Over CeO2-Supported Precious Metal Catalysts

Catalytic combustion of ethyl acetate was investigated over various CeO2-supported precious metal catalysts prepared by impregnation method, and the effect of reduction treatment on the activity was examined. Among the catalysts tested, Ru/CeO2 achieved the highest activity for ethyl acetate combustion, and the activity was almost unchanged by the heat treatment in a hydrogen atmosphere. In the cases of Pt/CeO2, Pd/CeO2, and Rh/CeO2, the catalytic activity was enhanced by the reduction treatment at 400 °C, though the activity of the reduced catalysts was still inferior to that of Ru/CeO2. It was confirmed by temperature-programmed reduction that the reduction of the ruthenium species was initiated at the lowest temperature among the CeO2-supported precious metals. The precious metal species reducible at lower temperatures should be responsible for the high activity in the complete oxidation of ethyl acetate.

Catalytic Combustion of Ethyl Acetate over Nanostructure Cobalt Supported ZSM‐5 Zeolite Catalysts

Abstract Gas phase catalytic combustion of ethyl acetate, as one of volatile organic compounds (VOC), was studied on nanostructure ZSM‐5, HZSM‐5 and Co‐ZSM‐5 with different cobalt loadings. Nanostructure of ZSM‐5 was determined by XRD, SEM and TEM. Catalytic studies were carried out under atmospheric pressure in a fixed bed reactor. Results showed that the Co‐ZSM‐5 catalysts had better activity than others and at temperatures below 350 °C, amount of Co loading was more effective on catalytic activity. The order of conversion of ethyl acetate over different Co loading is as follows: Co‐ZSM‐5 (0.75 wt%)<Co‐ZSM‐5 (1.5 wt%)<Co‐ZSM‐5 (15 wt%)<Co‐ZSM‐5 (2.8 wt%). Besides the higher the inlet concentration of ethyl acetate, the lower the conversion yield, and oxygen concentration in catalytic oxidation conditions has not so large influence on conversion. Furthermore, the presence of water vapor in inlet gaseous feed has an inhibitive effect on ethyl acetate conversion and at the temperatures above 400?C, the effect decreases.

Catalytic Combustion of Ethyl Acetate over Al 2O 3- Ce 0.5Zr 0.5O 2 Supported Metal Oxide Catalysts

The catalysts for the combustion of ethyl acetate were prepared using Fe, Co, Cu, Cr, and Mn metal oxide as active components supported on Al 2O 3-Ce 0.5Zr 0.5O 2 mixed oxides and characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR), oxygen storage capacity measurement, BET surface area, XPS measurement, and activity test. According to the results of characterization, it was found that Cu/Al 2O 3-Ce 0.5Zr 0.5O 2 (1:2, mass ratio) and Mn/Al 2O 3-Ce 0.5Zr 0.5O 2 (1:2) catalysts presented excellent activity for the catalytic combustion of ethyl acetate, because of the more reducible species and high reducibility of the catalysts. For ethyl acetate oxidation, more than 99% conversion was achieved at 245 °C over catalysts Cu/Al 2O 3-Ce 0.5Zr 0.5O 2 (1:2) and Mn/Al 2O 3-Ce 0.5Zr 0.5O 2 (1:2, mass ratio), indicating that the catalysts had great potential for wide use.

Washcoating of metallic monoliths with a MnCu catalyst for catalytic combustion of volatile organic compounds

A ready-made MnCu catalyst showing a good performance in the combustion of volatile organic compounds has been deposited on FeCrAlloy® metallic monoliths by means of washcoating. With the aim of depositing a homogeneous and well-adhered layer of catalyst on the monoliths, the effects of a pre-coating with colloidal alumina as a primer, the solid concentration in the slurry, the addition of a stabilizer to the slurry, and the immersions number of the monolith in the slurry were studied. The addition of a stabilizer to the slurry was necessary to prevent sedimentation and to achieve reproducible washcoatings. The pre-coating of the monolith with the primer improved the washcoating adherence obtained with one impregnation but a better adherence did not compensate a lower solid load due to a lower surface roughness. A higher amount of deposited material was obtained with the slurry at 35 wt% making two impregnations. The obtained monoliths showed excellent catalytic activity in the combustion of ethyl acetate and toluene. The activity as well as the surface area and pore volume of each monolith increased with the amount of retained solid.

Support effect on complete oxidation of volatile organic compounds over Ru catalysts

Catalytic combustion of ethyl acetate, acetaldehyde, and toluene was investigated on various supported Ru catalysts prepared by the impregnation method, and the effect of reduction treatment on the activity was examined. Among the as-calcined catalysts tested, Ru/CeO2 showed the highest activity for all tests regardless of the pre-treatment in hydrogen atmosphere. The catalytic activity of Ru/SnO2 was significantly degraded by the reduction treatment, whereas the activity of Ru/ZrO2 and Ru/γ-Al2O3 was enhanced. To reveal these phenomena, the as-calcined and reduced catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), transmission electron microscopy (TEM), and BET surface area. The dispersion of ruthenium on the supports was evaluated by chemisorption methods of carbon monoxide. The catalytic activity was strongly related to ruthenium species easily oxidizable and reducible at low temperatures. Such ruthenium species were loaded on CeO2 in a highly dispersed state, resulting in the highest activity.

Nanosized perovskite-type oxides La 1− xSr xMO 3− δ (M = Co, Mn; x = 0, 0.4) for the catalytic removal of ethylacetate

Nanometer perovskite-type oxides La 1− x Sr x MO 3− δ (M = Co, Mn; x = 0, 0.4) have been prepared using the citric acid complexing-hydrothermal-coupled method and characterized by means of techniques, such as X-ray diffraction (XRD), BET, high-resolution scanning electron microscopy (HRSEM), X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption (TPD), and temperature-programmed reduction (TPR). The catalytic performance of these nanoperovskites in the combustion of ethylacetate (EA) has also been evaluated. The XRD results indicate that all the samples possessed single-phase rhombohedral crystal structures. The surface areas of these nanomaterials ranged from 20 to 33 m 2 g −1, the achievement of such high surface areas are due to the uniform morphology with the typical particle size of 40–80 nm (as can be clearly seen in their HRSEM images) that were derived with the citric acid complexing-hydrothermally coupled strategy. The XPS results demonstrate the presence of Mn 4+ and Mn 3+ in La 1− x Sr x MnO 3− δ and Co 3+ and Co 2+ in La 1− x Sr x CoO 3− δ , Sr substitution induced the rises in Mn 4+ and Co 3+ concentrations; adsorbed oxygen species (O −, O 2 −, or O 2 2−) were detected on the catalyst surfaces. The O 2-TPD profiles indicate that Sr doping increased desorption of the adsorbed oxygen and lattice oxygen species at low temperatures. The H 2-TPR results reveal that the nanoperovskite catalysts could be reduced at much lower temperatures (<240 °C) after Sr doping. It is observed that under the conditions of EA concentration = 1000 ppm, EA/oxygen molar ratio = 1/400, and space velocity = 20,000 h −1, the catalytic activity (as reflected by the temperature ( T 100%) for EA complete conversion) increased in the order of LaCoO 2.91 ( T 100% = 230 °C) ≈ LaMnO 3.12 ( T 100% = 235 °C) < La 0.6Sr 0.4MnO 3.02 ( T 100% = 190 °C) < La 0.6Sr 0.4CoO 2.78 ( T 100% = 175 °C); furthermore, there were no formation of partially oxidized by-products over these catalysts. Based on the above results, we conclude that the excellent catalytic performance is associated with the high surface areas, good redox properties (derived from higher Mn 4+/Mn 3+ and Co 3+/Co 2+ ratios), and rich lattice defects of the nanostructured La 1− x Sr x MO 3− δ materials.

Gold and iron nanoparticles in mesoporous silicas: Preparation and characterization

Abstract Gold and iron oxide nanoparticles in mesoporous silicas are prepared and characterized by N 2 -physisorption, XRD, TEM-EDAX, UV–Vis and Moessbauer spectroscopies. Their reductive behaviour and catalytic properties in ethylacetate combustion are also tested. The dispersion and intimate contact between the obtained gold and iron particles are affected not only by the preparation method and pretreatment temperature used, but could be successfully regulated by the pore accessibility of the host matrix.

Development of TiO 2/Ti wire-mesh honeycomb for catalytic combustion of ethyl acetate in air

Wire-mesh sheets coated with Ti particles were developed by using an electrophoretic deposition (EPD) method. They were thermally treated at various working conditions for enhancing the coating strength. The Ti layer was suitably porous and showed a good adherence to the wire surface, due to partial sintering of Ti particles after thermal treatment at 900 °C. Then additional calcination at 600 °C resulted in the formation of a thin TiO 2 layer (∼3 μm) on the outer surface of the Ti layer. After making Pt/TiO 2/Ti-coated wire-mesh honeycombs (WMH) successfully, they were applied in catalytic combustion of ethyl acetate in air. The activity was much higher than that of a ceramic honeycomb containing a similar catalyst composition, especially in the high temperature ranges. This is explained by the difference in external mass transfer rate between the two modules. TiO 2/Ti-WMH had several additional advantages: (i) the active catalyst platinum could be directly impregnated, since TiO 2 could be used as a catalyst support. This reduces the manufacturing process with one-step, viz., support washcoating. (ii) Since there is no additional washcoat, it can be expected that the possibility of catalyst loss during the operation becomes very low. (iii) A rapid thermal response due to the small heat capacity.

Sonochemically Prepared Pt/CeO2 and Its Application as a Catalyst in Ethyl Acetate Combustion

Highly dispersed Pt nanoparticles were incorporated in CeO2 nanopowders by an ultrasound-assisted reduction procedure. The activity of the Pt/CeO2 catalysts was studied in the reaction of the ethyl acetate combustion, and complete conversion was achieved at low temperature. It was demonstrated that the higher dispersion of the CeO2 support, the better the performance of the Pt/CeO2 catalysts. The catalysts were characterized by XRD, TEM, HRTEM, EDX, BET, and XPS. The homogeneous incorporation of 2-4 nm Pt nanoparticles into the interparticle distance of the CeO2 nanopowders was demonstrated. The advantage of the sonochemical method for catalyst preparation, in comparison with the traditional incipient wetness impregnation, was explained as the result of the homogeneity and better dispersion of the active metal phase obtained by ultrasound irradiation.

Catalytic combustion of ethyl acetate on supported copper oxide catalysts

Total oxidation of ethyl acetate on supported copper oxide catalysts was investigated. The catalysts have been prepared by wet impregnation method and characterized by XRD, TEM and XPS. Among the catalysts with the supports of TiO 2, CeO 2/TiO 2 and CeO 2–ZrO 2/TiO 2, CeO 2–ZrO 2 solid solutions doped TiO 2 supported catalyst gives the highest catalytic activity. Catalyst with the composition of 5 wt.% CuO/10 wt.% CeO 2–ZrO 2–TiO 2 shows the total oxidation of ethyl acetate at about 270 °C with the 100% CO 2 selectivity. The characterization studies of supported copper oxide catalysts showed that the highly dispersed CuO is one of the active phase which contacts intimately with the support, the action of the interface between the components was not be ignored.

A highly efficient copper supported catalyst for catalytic combustion of ethyl acetate

CeO 2 and/or ZrO 2 modified titania supports and the supported copper oxide catalysts were prepared by impregnation method using nitrate. Catalytic combustion of ethyl acetate has been measured in the temperature range 100–360 °C, and the structural and properties were characterized by means of TPR, XRD and XPS technologies. The results show that CeO 2–ZrO 2 modified TiO 2 support highly enhanced the dispersion of CuO phase, resulting in improving the catalytic activity and suppressed the form of by-product such as ethanol and aldehyde. The complete decomposition of ethyl acetate was achieved at about 280 °C with the 100% CO 2 selectivity.

Catalytic combustion of ethyl acetate over ceria-promoted platinum supported on Al2O3 and ZrO2 catalysts

Platinum-supported catalysts prepared by impregnation of mixed CeO2/Al2O3 and CeO2/ZrO2 oxides using the sol-gel method were characterized and used in the combustion of ethyl acetate. In each series, the effect of CeO2 loading (3 and 5 wt%) was studied. Characterization data from the studied catalysts (specific area measurements, hydrogen chemisorption, programmed temperature reduction (TPR), X-ray diffraction (XRD), photoelectron spectra (XPS) and transmission electron microscopy (TEM)) revealed significant changes in porosity and metal dispersion in each series. The catalytic activity of the solids, evaluated in the total combustion of ethyl acetate, exhibited a positive effect with the addition of Ce in the zirconia series whereas no significant changes was observed in the alumina series.

Copper oxide modified large pore ordered mesoporous silicas for ethyl acetate combustion

Copper oxide supported on large pore ordered mesoporous silicas with channel- and cage-like structures are obtained and characterized with N 2-physisorption, XRD, XPS and TPR with hydrogen. The state of copper species, their reductive properties and catalytic behaviour in ethyl acetate combustion are significantly influenced by the silicas pore architecture.

Performance of H‐ZSM‐5‐supported bimetallic catalysts for the combustion of polluting volatile organic compounds in air

AbstractThe performance of H‐ZSM‐5‐supported bimetallic catalysts with chromium as the base metal in the combustion of ethyl acetate and benzene is reported. A reactor operated from 100 to 500 °C at a gas hourly space velocity (GHSV) of 32 000 h−1 was used for study of the activity. A combination of 1.0 wt% chromium and 0.5 wt% copper yielded a catalyst (Cr1.0Cu0.5/Z) with improved conversion and carbon dioxide yield. Cr2O3 (Cr3+) and CuO (Cu2+) were the predominant metal species in the catalyst. In agreement with the Mars–van Krevelen model, improved reducibility of Cr3+ in the presence of Cu2+ led to an improvement in activity. The copper content in Cr1.0Cu0.5/Z also favored the formation of deep combustion products. Condensation and subsequent growth of coke precursors in the catalyst pores led to the formation of a softer and less aromatic coke fraction while dehydrogenation activity on acid sites formed a harder and more aromatic coke fraction. The use of Cr1.0Cu0.5/Z favored the formation of lower molecular weight intermediates, leading to reduction in formation of softer coke. Copyright © 2005 Society of Chemical Industry

Evaluation of wire-mesh honeycomb containing porous Al/Al 2O 3 layer for catalytic combustion of ethyl acetate in air

Wire-mesh honeycomb (WMH) catalyst is a monolith made from layers of flat and corrugated wire-meshes. To obtain an attrition-resistant washcoat on mesh surface, the mesh substrate was pre-coated with aluminum powder by electrophoretic deposition. A well-adhered aluminum layer was formed on wire-mesh surface after thermal treatment at 800 °C. Then, additional tuned calcination results in the formation of a thin Al 2O 3 layer in the outer surface of deposited aluminum particles. The Al/Al 2O 3-WMH was evaluated for catalytic combustion of ethyl acetate, a typical refractory volatile organic compound (VOC), after washcoating Pt/TiO 2 catalyst on it. The conversion over Al/Al 2O 3-WMH did not decrease during the long-term operation, since the primer layer of Al/Al 2O 3 enhanced the catalyst adhesion. Results were compared with conventional ceramic honeycomb (CH) containing the same cell density and catalyst loading. The activity of WMH was much higher than that of CH, especially at the high-temperature ranges. It was due to the difference in external mass transfer rate between two modules. The fact was confirmed by the calculation of the external mass transfer coefficient of WMH and CH.

Modeling of the deactivation kinetics for the combustion of ethyl acetate and benzene present in the air stream over ZSM-5 catalyst loaded with chromium

Deactivation kinetics of chromium exchanged ZSM-5 (Cr-ZSM-5, Si/Al=240) catalyst by coking during the combustion of ethyl acetate (EAc) and benzene (Bz) present in the air stream is reported. Lumped coking deactivation model (LCDM), monolayer–multilayer coking deactivation model (MMDM) and heterogeneous surface coking deactivation model (HSDM) are used for the analysis of deactivation process. Coked Cr-ZSM-5 was prepared by exposing the catalyst to 32,000 ppm of each organic at gas hourly space velocity (GHSV) of 3800 h −1 and temperature 400 °C for a period of 12 h. The activity data were obtained with 2000 ppm of each organic at 400 °C and GHSV of 78,900 h −1. HSDM accurately predicted progressive coke content, activity with time-on-stream and profiles of activity–coke content for both organics. In line with experimental observations, the model predicted faster activity drop with lower residual activity during the combustion of ethyl acetate. The combustion reaction of ethyl acetate and benzene could take place over both coking sites ( S c) and metal sites ( S t) but, the role of S t was more dominant especially in benzene combustion.

TiO 2 and ZrO 2 crystals in SBA-15 silica: performance of Pt/TiO 2(ZrO 2)/SBA-15 catalysts in ethyl acetate combustion

TiO 2 (40–64 wt%) and ZrO 2 (48–62 wt%) were inserted in SBA-15 mesostructured silica by chemical solution decomposition or hydrolysis of the corresponding alkoxides inside the host pores. It yielded composites with 85–94% TiO 2 crystallinity (anatase) and >95% crystallinity of ZrO 2 (tetragonal phase). The 4.5 nm (ZrO 2) or 5.0 and 8.5 nm (TiO 2) nanocrystals did not block the SBA-15 pores, and their surface was fully accessible for adsorbed nitrogen or ethyl acetate molecules. After deposition of 0.3 wt% Pt the activity of Ti(Zr)O 2/SBA-15 materials in ethyl acetate combustion was proportional to the surface area of the corresponding transition metal oxide nanoparticles, being a function of their loading and crystal size. The platinized composite materials displayed 1.7–3 times higher activity compared with platinum on bulk Ti(Zr)O 2 oxides prepared by the same methods and two orders of magnitude higher activity relative to Pt/SBA-15 and Pt/ γ-Al 2O 3 catalysts.