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1.
The possibility of the integration of the processes of H2O2 production through isopropanol partial oxidation and the direct ammoximation of cyclohexanone with H2O2 and NH3 catalyzed by TS‐1 was investigated. The results of isopropanol partial oxidation showed that around 7.5 % yield of H2O2 was obtained at 110 °C, 10 atm, 2 h, and after fractionation, a H2O2 solution with the typical composition 25.2 wt.‐% H2O2, 10.3 wt.‐% isopropanol, 0.29 wt.‐% acetone, 0.45 wt.‐% phosphoric acid and 0.43 wt.‐% acetic acid was obtained. The presence of these impurities up to the above levels did not appreciably influence the ammoximation of cyclohexanone in terms of the conversion of cyclohexanone and the selectivity to cyclohexanone oxime. The results indicate that the processes of H2O2 production through isopropanol partial oxidation and the ammoximation of cyclohexanone can be integrated. 相似文献
2.
R. Prasad Seema Vashisht 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1997,68(3):310-314
The ammoximation of cyclohexanone to cyclohexanone oxime with H2O2 and NH3, in liquid phase, over γ-Al2O3 supported titanium silicates, is reported. The effects of temperature, reactant concentrations and support to catalyst ratio on the efficiency of the process are examined. A maximum yield of 94·48% with selectivity 98·49% for oxime could be achieved over 50 wt% γ-Al2O3 supported titanium silicates, at a cyclohexanone: NH3: H2O2 molar ratio of 1:1·5:1, and at a temperature of 313 K. Studies suggest that in the case of a supported catalyst, the catalyst: ketone ratio is about eight times less than that needed for an unsupported catalyst. A batchwise addition of cyclohexanone and ammonia and a dropwise addition of H2O2 produced the best results. A tentative mechanism for the production of oxime and by-products is suggested. © 1997 SCI. 相似文献
3.
The ammoximation of different ketones and aldehydes to their corresponding oximes catalyzed by K6[PW9V3O40]·4H2O was carried out with hydrogen peroxide and ammonia in isopropanol at room temperature. High yields of oximes were obtained in this catalytic system. This catalytic system was proved to be heterogeneous by the ammoximation activity of removal of catalyst and the elemental analysis of the filtrate after reaction. A possible procedure for the ammoximation catalyzed by K6[PW9V3O40]·4H2O with H2O2 and NH3·H2O was proposed. The fresh and used catalysts were characterized by IR and 31P MAS NMR, which revealed the good stability of the catalyst. 相似文献
4.
Daniele Bianchi Luigi Balducci Rossella Bortolo Rino D'Aloisio Marco Ricci Guido Span Roberto Tassinari Cristina Tonini Raffaele Ungarelli 《Advanced Synthesis \u0026amp; Catalysis》2007,349(6):979-986
The hydroxylation of benzene to phenol with hydrogen peroxide was investigated using different solvents and a series of catalysts, obtained by modification of titanium silicalite (TS‐1). The best results were obtained after post‐synthesis treatment of TS‐1 with NH4HF2 and H2O2. The new catalyst (TS‐1B), used in the presence of a particular co‐solvent (sulfolane) is able to protect the produced phenol from over‐oxidation and dramatically enhanced the selectivity of the reaction. 相似文献
5.
Agnieszka Wróblewska Eugeniusz Milchert 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2007,82(7):681-686
The influence of the technological parameters on the course of the epoxidation of allyl alcohol with 30% H2O2 in the presence of titanium silicalite TS‐2 catalyst and methanol as a solvent was studied. The process was performed in an autoclave at the autogenic pressure. The influence of temperature in the range 20–120 °C, molar ratio of allyl alcohol/H2O2 (1:1–10:1), methanol concentration in the reaction mixture (10–80% w/w), catalyst TS‐2 concentration (0.1–2.0% w/w) and reaction time (1–8 h) were investigated. The functions describing the process were: selectivity of transformation to glycidocidol in relation to allyl alcohol consumed, selectivity of transformation to organic compounds in relation to hydrogen peroxide consumed, conversions of allyl alcohol and hydrogen peroxide. Copyright © 2007 Society of Chemical Industry 相似文献
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Agnieszka Wróblewska Joanna Wajzberg Anna Fajdek Eugeniusz Milchert 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(9):1344-1349
BACKGROUND: The influence of technological parameters on the epoxidation of 1‐butene‐3‐ol (1B3O) over titanium silicalite TS‐2 catalyst has been investigated. Epoxidations were carried out using 30%(w/w) hydrogen peroxide at atmospheric pressure. The major product from the epoxidation of B3O was 1,2‐epoxybutane‐3‐ol, with many potential applications. RESULTS: The influence of temperature (20–60 °C), 1B3O/H2O2 molar ratio (1:1–5:1), methanol concentration (5–90%(w/w)), TS‐2 catalyst concentration (0.1–6.0%(w/w)) and reaction time (0.5–5.0 h) have been studied. CONCLUSION: The epoxidation process is most effective if conducted at a temperature of 20 °C, 1B3O/H2O2 molar ratio 1:1, methanol concentration (used as the solvent) 80%(w/w), catalyst concentration 5%(w/w) and reaction time 5 h. Copyright © 2009 Society of Chemical Industry 相似文献
8.
Idil Arslan‐Alaton Asli Akin Tugba Olmez‐Hanci 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2010,85(4):493-501
BACKGROUND: Industrial surfactants are biologically complex organics that are difficult to degrade and may cause ecotoxicological risks in the environment. Until now, many scientific reports have been devoted to the effective treatment of surfactants employing advanced oxidation processes, but there is no available experimental study dealing with the optimization and statistical design of surfactant oxidation with the well‐established H2O2/UV‐C process. RESULTS: Considering the major factors influencing H2O2/UV‐C performance as well as their interactions, the reaction conditions required for the complete oxidation of a commercial non‐ionic textile surfactant, an alkyl ethoxylate, were modeled and optimized using central composite design‐response surface methodology (CCD‐RSM). Experimental results revealed that for an aqueous non‐ionic surfactant solution at an initial chemical oxygen demand (COD) of 450 mg L?1, the most appropriate H2O2/UV‐C treatment conditions to achieve full mineralization at an initial pH of 10.5 were 47 mmol L?1 H2O2 and a reaction time of 86 min (corresponding to a UV dose of 30 kWh m?3). CONCLUSION: CCD allowed the development of empirical polynomial equations (quadratic models) that successfully predicted COD and TOC removal efficiencies under all experimental conditions employed in the present work. The process variable treatment time, followed by the initial COD content of the aqueous surfactant solution were found to be the main parameters affecting treatment performance, whereas the initial H2O2 concentration had the least influence on advanced oxidation efficiencies. The H2O2 concentration and surfactant COD were found to be more important for TOC abatement compared with COD abatement. Copyright © 2009 Society of Chemical Industry 相似文献
9.
F. Frusteri E. N. Savinov A. Parmaliana E. R. Savinova V. N. Parmon N. Giordano 《Catalysis Letters》1994,27(3-4):355-360
Selective partial oxidation of ethane to ethanol and acetaldehyde by in situ generated H2O2 has been achieved under cathodic current passing through a carbon supported Nafion-H catalytic membrane. A correlation between H2O2 generation rate and reaction rate has been found. 相似文献
10.
Sarla Malhotra M Pandit JC Kapoor DK Tyagi 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(1):13-19
Photo‐oxidation of cyanide was studied in aqueous solution using a low‐pressure ultra‐violet (UV) lamp along with H2O2 as an oxidant. It was observed that by UV alone, cyanide degradation was slow but when H2O2 was used with UV, the degradation rate became faster and complete degradation occurred in 40 min. The rate of degradation increased as the lamp wattage was increased. It was also observed that cyanide oxidation is dependent on initial H2O2 concentration and the optimum dose of H2O2 was found to be 35.3 mmol dm?3. Photo‐oxidation reactions were carried out at alkaline pH values (10–11) as at acidic pH values, cyanide ions form highly toxic HCN gas which is volatile and difficult to oxidise. By the UV/H2O2 process, using a 25 W low‐pressure UV lamp and at alkaline pH of 10.5 with an H2O2 dose of 35.3 mmol dm?3, cyanide (100 mg dm?3) was completely degraded in 40 min when air was bubbled through the reactor, but when pure oxygen was bubbled the time reduced to 25 min. The cyanide degradation reaction pathway has been established. It was found that cyanide was first oxidised to cyanate and later the cyanate was oxidised to carbon dioxide and nitrogen. The kinetics of cyanide oxidation were found to be pseudo‐first order and the rate constant estimated to be 9.9 × 10?2min?1 at 40 °C. The power required for complete degradation of 1 kg of cyanide was found to be 167 kWh (kilowatt hour). Copyright © 2004 Society of Chemical Industry 相似文献
11.
Lei Zhigang Zhang Jinchang Chen Biaohua 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(11):1251-1254
A new separation method of reactive extractive distillation is proposed for the separation of isopropanol and water, using the mixture of ethylene glycol (C2H6O2) and glycollic potassium (C2H5O2K) as an entrainer. Vapor–liquid‐equilibrium (VLE) measurements confirmed that the entrainer was effective for this separation. Using a feed/solvent volume ratio of 1:1, isopropanol with a concentration over 96.0% weight fraction was obtained by the reactive extractive distillation process and the azeotropic point was eliminated. A novel process of separating isopropanol and water is designed on the basis of reactive extractive distillation to obtain the product with different concentrations, which may have a lasting value in industry. © 2002 Society of Chemical Industry 相似文献
12.
Basic rules of NO oxidation by a Fe2+/H2O2/AA directional decomposition system were researched based on the technical background of flue gas NOx removal. Effects of gas‐liquid interfacial area, main gas, and solution parameters on NO oxidation efficiency (η) were analyzed. The results showed that adequate contact area was the precondition for high η by a Fe2+/H2O2/AA system. η decreased with the increase in NO concentration, which illustrated that this method would be efficient in oxidizing NO at a low concentration. η tended to decrease linearly with the growth in gas flow, however, the NO oxidation rate (v) rose with the increase in NO concentration and gas flow. η increased with the initial concentrations of H2O2 and Fe2+, but the amplitude decreased. Controlling the initial concentrations of H2O2 and Fe2+ to achieve reasonable synergies between generation rate and consumption rate of ·OH could weaken the invalid consumption of reactants. η increased with the increase in temperature in the range 30–60 °C, but it nearly did not change with temperature after 60 °C. This oxidation technology and the traditional wet flue gas desulphurization technology exhibited temperature synergy. Under typical pH of wet desulphurization, η and H2O2 consumption rate did not change obviously. 相似文献
13.
This laboratory study was designed to investigate the degradation of 4-chloronitrobenzene ([CNB] = 2.4 × 10?6 mol L?1; pH = 7.5) by H2O2/UV and by O3/UV oxidation processes which involve the generation of very reactive and oxidizing hydroxyl free radicals. The effects of the oxidant doses (H2O2 or aqueous O3), liquid flow rate (or the contact time), and bicarbonate ions acting as OH· radical scavengers on the CNB removal rates were studied. For a constant oxidant dose, the results show that the O3/UV system appears to be more efficient than the H2O2/UV system to remove CNB because of the greatest rate of OH· generation by ozone photodecomposition compared to H2O2 photolysis. However, for a given amount of oxidant decomposed, the H2O2/UV oxidant system was found to be more efficient than O3/UV. Moreover, high levels of bicarbonate ions in solution (4 × 10?3 mol L?1) significantly decrease the efficiency of CNB removal by H2O2/UV and by O3/UV oxidation processes. 相似文献
14.
Continuous and scale‐up synthesis of high purity H2O2 by safe gas‐phase H2/O2 plasma reaction
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Yanhui Yi Juncheng Zhou Tianlong Gao Hongchen Guo Juncheng Zhou Jialiang Zhang 《American Institute of Chemical Engineers》2014,60(2):415-419
A new generation of double dielectric barrier discharge (DDBD) reactor featured by a metal powder (MP) high voltage electrode is presented. The MP high voltage electrode not only has excellent homogeneous discharge performance but also has the advantage of without regular maintenance. Therefore, the MP‐DDBD reactor was proved to be suitable for the uninterrupted and safe synthesis of high purity H2O2 aqueous solution with up to 65 wt % concentration from the H2/O2 mixture. The scale‐up synthesis of H2O2 was successfully attempted in an integrated device based on the MP‐DDBD reactor. The future practical H2O2 synthesizer based on the MP‐DDBD reactor will be small and movable, and therefore, be convenient to supply high purity H2O2 on site for small scale users like semiconductor industry. © 2013 American Institute of Chemical Engineers AIChE J 60: 415–419, 2014 相似文献
15.
Stefanie Tamm Louise Olsson Sebastian Fogel Pär Gabrielsson Magnus Skoglundh 《American Institute of Chemical Engineers》2013,59(11):4325-4333
A global kinetic model which describes H2‐assisted NH3‐SCR over an Ag/Al2O3 monolith catalyst has been developed. The intention is that the model can be applied for dosing NH3 and H2 to an Ag/Al2O3 catalyst in a real automotive application as well as contribute to an increased understanding of the reaction mechanism for NH3‐SCR. Therefore, the model needs to be simple and accurately predict the conversion of NOx. The reduction of NO is described by a global reaction, with a molar stoichiometry between NO, NH3 and H2 of 1:1:2. Further reactions included in the model are the oxidation of NH3 to N2 and NO, oxidation of H2, and the adsorption and desorption of NH3. The model was fitted to the results of an NH3‐TPD experiment, an NH3 oxidation experiment, and a series of H2‐assisted NH3‐SCR steady‐state experiments. The model predicts the conversion of NOx well even during transient experiments. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4325–4333, 2013 相似文献
16.
The oxidation of liquid cyclohexane by O2 over UV-illuminated TiO2 at room temperature has been studied in a static slurry reactor. From the effects of the mass of catalyst, the temperature, the radiant flux, the concentration of C6H12 (using acetonitrile as a solvent), it is concluded that the reaction is photocatalytic. Using mainly the 365 nm-ray of a mercury-lamp, an initial quantum yield of 0.1 is found for pure cyclohexane and radiant fluxes < ca.5mWcm–2 (6×1015 photons s–1 cm–2). A high selectivity to cyclohexanone is observed (83%), the other products being cyclohexanol (5%) and CO2 (12%). The low amount of cyclohexanol is explained by the higher rate of oxidation of this alcohol compared to that of cyclohexane. Smaller oxidation rates are observed when TiO2 is loaded with 0.5 to 10 wt%Pt and the cyclohexanone/cyclohexanol ratio decreases to ca. 4. Finally, the C6H12 oxidation has been employed as a test reaction to confirm the detrimental effect of the doping with several tri or pentavalent cations upon the photocatalytic activity of TiO2. 相似文献
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A series of hydrotalcite-like compounds were prepared under microwave irradiation, which were used to catalyze the Baeyer–Villiger oxidation of cyclohexanone to ε-caprolactone with hydrogen peroxide as oxidant. The results show that stibium-containing hydrotalcite (Sb-HTL) has good catalytic properties in the reaction. In the Baeyer–Villiger oxidation of cyclohexanone to ε-caprolactone with H2O2 catalyzed by Sb-HTL, the effects of reaction time, reaction temperature, amount of catalyst and H2O2/cyclohexanone molar ratio are also investigated in details. It is shown the cyclohexanone conversion and ε-caprolactone selectivity can reach 79.15 and 93.84%, respectively, under the optimum reaction conditions. Furthermore, Sb-HTL can be reused for six times without obvious loss of activity and selectivity. Therefore, Sb-HTL is reusable and would be a promising catalyst for the Baeyer–Villiger oxidation using green and cheap oxidants like hydrogen peroxide instead of peroxycarboxylic acids. 相似文献
19.
Au/TS‐1 catalyst for propene epoxidation with H2/O2: A novel strategy to enhance stability by tuning charging sequence
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Xiang Feng Yibin Liu Yichuan Li Chaohe Yang Zhihua Zhang Xuezhi Duan Xinggui Zhou De Chen 《American Institute of Chemical Engineers》2016,62(11):3963-3972
For propene epoxidation with H2 and O2, the catalytic performance of Au/TS‐1 catalyst is extremely sensitive to preparation parameters of deposition‐precipitation (DP) method. In this work, effect of charging sequence in DP process on catalyst structure and catalytic performance of Au/TS‐1 catalyst is first investigated. For different charging sequences, the compositions of Au complexes (e.g., [AuCl(OH)3]?) and pore property of TS‐1 (i.e., with or without H2O prefilling micropores) could affect the transfer of Au complexes into the micropores, resulting in different Au locations and thus significantly different catalytic performance. Notably, when TS‐1 is first filled with H2O and then mixed with Au complexes, the reduced Au/TS‐1 catalyst could expose Au nanoparticles on the external surface of TS‐1 and show high stability. The results provide direct evidence showing that micropore blocking is the deactivation mechanism. Based on the results, a simple strategy to design highly stable Au/Ti‐based catalysts is developed. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3963–3972, 2016 相似文献
20.
Idil Arslan Isil Akmehmet Balcioglu 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2001,76(1):53-60
The advanced chemical oxidation of raw and biologically pretreated textile wastewater by (1) ozonation, (2) H2O2 /UV − C oxidation and (3) sequential application of ozonation followed by H2O2 /UV − C oxidation was investigated at the natural pH values (8 and 11) of the textile effluents for 1 h. Analysis of the reduction in the pollution load was followed by total environmental parameters such as TOC, COD, UV–VIS absorption kinetics and the biodegradability factor, fB. The successive treatment combination, where a preliminary ozonation step was carried out prior to H2O2 /UV − C oxidation without changing the total treatment time, enhanced the COD and TOC removal efficiency of the H2O2 /UV − C oxidation by a factor of 13 and 4, respectively, for the raw wastewater. In the case of biotreated textile effluent, a preliminary ozonation step increased COD removal of the H2O2 /UV − C treatment system from 15% to 62%, and TOC removal from 0% to 34%. However, the sequential process did not appear to be more effective than applying a single ozonation step in terms of TOC abatement rates. Enhancement of the biodegradability factor (fB) was more pronounced for the biologically pretreated wastewater with an almost two‐fold increase for the optimized Advanced Oxidation Technologies (AOTs). For H2O2 /UV − C oxidation of raw textile wastewater, apparent zero order COD removal rate constants (kapp), and the second order OH· formation rates (ri) have been calculated. © 2001 Society of Chemical Industry 相似文献