Sulfonated carbon as a strong and stable solid acid catalyst exhibited excellent catalytic performance in various acid-catalyzed reactions. Here, sulfonated carbon, as catalyst for oxidation reaction, was prepared via...Sulfonated carbon as a strong and stable solid acid catalyst exhibited excellent catalytic performance in various acid-catalyzed reactions. Here, sulfonated carbon, as catalyst for oxidation reaction, was prepared via the carbonization of starch followed by sulfonation with concentrated sulfuric acid. N2 physisorption, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray fluorescence and acid-base titration were used to characterize the obtained materials. The catalytic activity of sulfonated carbon was studied in the oxidation of aldehydes to carboxylic acids using 30 wt% H2O2 as oxidant. This oxidation protocol works well for various aldehydes including aromatic and aliphatic aldehydes. The sulfonated carbon can be recycled for three times without obvious loss of activity.展开更多
Sn-aniline complex was prepared by a simple procedure.Cyclic and acyclic ketones were oxidized into lactones or esters with very high selectivity and yield with 30% hydrogen peroxide in the presence of Sn-aniline comp...Sn-aniline complex was prepared by a simple procedure.Cyclic and acyclic ketones were oxidized into lactones or esters with very high selectivity and yield with 30% hydrogen peroxide in the presence of Sn-aniline complex.展开更多
The selective catalytic oxidation of toluene with hydrogen peroxide over V-Mo-based catalysts under mild conditions was studied.The promotion effect of Mo on the catalysts was studied with V/Al2O3 and Mo/Al2O3 as refe...The selective catalytic oxidation of toluene with hydrogen peroxide over V-Mo-based catalysts under mild conditions was studied.The promotion effect of Mo on the catalysts was studied with V/Al2O3 and Mo/Al2O3 as reference samples.The catalysts were characterized by XRD,TPR,and XPS techniques.The results show that the addition of Mo to V/Al2O3 may change the distribution of V species on Al2O3 surface.Over V-Mo/Al2O3 catalyst,highly dispersed amorphous V species facilitates benzaldehyde formation,and crystalline V2O5 species increases the conversion of toluene but decreases the selectivity to benzaldehyde,while AlVMoO7 species favors both the conversion of toluene and the formation of cresols.The yield of benzaldehyde depends remarkably on the surface O/Al and Mo/V atomic ratios,and gets to a maximum value of 13.2% with a selectivity of 79.5% at an O/Al atomic ratio of 3.0 and Mo/V atomic ratio of 0.7.展开更多
An investigation on the process of ozone combined with hydrogen peroxi de and ultraviolet radiation has been carried out in order to establish the kine tics for photochemical oxidation of polyacrylamide (PAM) in aqueo...An investigation on the process of ozone combined with hydrogen peroxi de and ultraviolet radiation has been carried out in order to establish the kine tics for photochemical oxidation of polyacrylamide (PAM) in aqueous solution. Ef fects of operating parame- ters, including initial PAM concentration, dosages of ozone and hydrogen peroxide, UV radiation and pH value on the photochemical oxi dation of PAM, have been studied. There was an increase in photochemical oxidati on rate of PAM with increasing of dosages of O3, H2O2 and ultraviolet radiation. Upon increasing of the initial PAM concentration, the photochemical oxidation r ate of PAM decreased. Slight effect of pH value on the photochemical oxidation r ate of PAM was observed in the experiments. The kinetics equation for the photoc hemical oxidation of PAM by the system has been established.展开更多
A series of CoPd/KIT-6 bimetallic catalysts with various Co:Pd molar ratios at different calcination temperatures were prepared and used for the direct synthesis of H_(2)O_(2) from H_(2) and O_(2).These catalysts were...A series of CoPd/KIT-6 bimetallic catalysts with various Co:Pd molar ratios at different calcination temperatures were prepared and used for the direct synthesis of H_(2)O_(2) from H_(2) and O_(2).These catalysts were characterized by nitrogen adsorption-desorption,low and wide-angle X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM),scanning electron microscopy(SEM),elemental mapping and energy-dispersive X-ray(EDX)methods.It was found that the particle size,electronic interactions,morphology,and textural properties of these catalysts as well as their catalytic activity in the reaction of H_(2) with O_(2) were affected by Co addition and different calcination temperatures.Also,the results showed that while the H_(2)O_(2) selectivity depends on Pd^(2+) species,the H_(2) conversion is related to Pd0 active sites.Among these catalysts,CoPd/KIT-6 calcined at 350℃(CoPd/KIT-350 catalyst)showed the best catalytic activity with 50%of H_(2)O_(2) selectivity and 51%conversion of H_(2).展开更多
Basic organic chemicals and high value–added products are mainly produced by hydrocarbon nitridation and oxidation.However,several drawbacks limit the application of the traditional oxidation and nitridation technolo...Basic organic chemicals and high value–added products are mainly produced by hydrocarbon nitridation and oxidation.However,several drawbacks limit the application of the traditional oxidation and nitridation technologies in the future,such as complex processes,poor intrinsic safety,low atom utilization,and serious environmental pollution.The green nitridation and oxidation technologies are urgently needed.Hydrogen peroxide,a well–known green oxidant,is widely used in green hydrocarbon oxidation and nitridation.But its industrial production in China adopts fixed–bed technology,which is fall behind slurry–bed technology adopted by advanced foreign chemical companies,limiting the development of hydrogen peroxide industry and green hydrocarbon nitridation or oxidation industry.This article reviews the industrial production technologies of hydrogen peroxide and basic organic chemicals such as caprolactam,aniline,propene oxide,epichlorohydrin,phenol,and benzenediol,especially introduces the green production technologies of basic organic chemicals related with H_(2)O_(2).The article also emphasis on the efforts of Chinese researchers in developing its own slurry–bed technology of hydrogen peroxide production,and corresponding green hydrocarbon nitridation or oxidation technologies with hydrogen peroxide.Compared with traditional nitridation or oxidation technologies,green production technologies of caprolactam,propene oxide,epichlorohydrin,and benzenediol with hydrogen peroxide promote the nitrogen atom utilization from 60%to near 100%and the carbon atom utilization from 80%to near 100%.The waste emissions and environmental investments are reduced dramatically.Technological blockade against the green chemical industry of China are partially broken down,and technological upgrade in the chemical industry of China is guaranteed.展开更多
Objective:To evaluate the biomarkers of oxidative stress in herpes zoster patients compared with control subjects.Methods:This study compared the nitric oxide(NO),hydrogen peroxide(H2 O2),malon dialdehyde,uric acid,an...Objective:To evaluate the biomarkers of oxidative stress in herpes zoster patients compared with control subjects.Methods:This study compared the nitric oxide(NO),hydrogen peroxide(H2 O2),malon dialdehyde,uric acid,and bilirubin levels between 43 herpes zoster patients and 47 age-matched control subjects.The area under the curve of the receiver operating characteristic curve was performed to evaluate the final logistic regression model.Results:The significant differences were observed in the serum levels of NO,H2 O2,and malondialdehyde between the case and the control groups(P<0.001).However,no statistical differences were found in both uricacid and bilirubin levels between the groups.Additionally,the raised oxidant biomarkers were strongly associated with increased disease severity(P<0.001).Multiple logistic regression analysis with the highest area under the curve[0.98(95%CI 0.95-1.00)]and the minimum number of variables showed that high levels of NO(OR 1.24;95%CI 1.06-1.46;P=0.008)and H2 O2(OR 1.25;95%CI 1.09-1.43;P=0.001)were associated with herpes zoster.Conclusions:High levels of NO and H2 O2 were observed in patients with herpes zoster.Increased NO and H2 O2 levels might be associated with herpes zoster,which needs to be confirmed by further studies.展开更多
Background:Hepatocellular carcinoma(HCC)has a high incidence and mortality that epitomizes one of the prominent causes of cancer-related death globally.Novel therapeutic approaches are therefore required.Reactive oxyg...Background:Hepatocellular carcinoma(HCC)has a high incidence and mortality that epitomizes one of the prominent causes of cancer-related death globally.Novel therapeutic approaches are therefore required.Reactive oxygen species(ROS)are necessary for maintaining cell cycle.Although ROS is involved in HCC progression,hydrogen peroxide(H2O2)has anti-proliferative effect on HCC.Method:HCC Huh-7 cells were cultured and incubated with various concentrations of H2O2.Paraoxonase activity,levels of malondialdehyde,glutathione and protein oxidation were measured in treated and untreated Huh-7 cells.Furthermore,untreated and treated Huh-7 cells were subjected to two dimensional gel electrophoresis and identified protein spots which were differentially expressed by LC-MS/MS analysis.q RT-PCR was performed to validate the identified proteins.Results:H2O2 depleted glutathione(GSH)with the concomitant up-regulation of GSTP1 and Prx2.H2O2 also increased malondialdehyde and protein oxidation,decreased the activity of paraoxonase in Huh-7 cells.Conclusion:H2O2 could be used as a novel therapeutic agent that might be beneficial in inducing cell cytotoxicity and hence suppress HCC proliferation.展开更多
The green and effective Baeyer-Villiger oxidation reaction of cyclohexanone for preparing ε-caprolactone is of particular importance in the synthesis of new polymer materials. We have discussed here several mechanism...The green and effective Baeyer-Villiger oxidation reaction of cyclohexanone for preparing ε-caprolactone is of particular importance in the synthesis of new polymer materials. We have discussed here several mechanism types of Baeyer-Villiger oxidation of cyclohexanone with H2O2 in different reaction systems. Five main types have been addressed, i. e.: (1) the non-catalyzed reaction type, where the C=O of ketones is activated by H+, which is electrolytically dissociated from H2O2 and H2O, to improve the capability of C=O group for accepting the electron pairs; (2) the thermally activated radical reaction type, where the Criegee intermediate is produced via two steps of radical reaction with ·OH attack, with much more hydroxyl radicals being excited in the presence of TS-1 zeolite; (3) the Brnsted acid catalysis reaction type, where both O-O moiety and C=O group could be activated by Brnsted acid; (4) the solid Lewis acid catalyzed C=O of the substrate activation reaction type through enhancing the donor-acceptor interaction between the antibonding π*C=O orbital of cyclohexanone and HOMO of Sn-containing zeolites; and (5) the solid Lewis acid catalyzed H2O2 to form Me-OOH oxidative species by converting the highest occupied molecular orbital (HOMO) of Ti-OOH into a singly occupied molecular orbital (SOMO), making the O-O group highly electrophilic to attack the C=O of cyclohexanone during the Baeyer-Villiger oxidation process. In the end, we have also compared the different mechanisms and put forward our opinions on the development direction of catalytic materials aiming at eco-friendly Baeyer-Villiger oxidation of cyclohexanone in the years to come.展开更多
Oxidation of sulfide in aqueous solution by hydrogen peroxide was investigated in the presence of hydrated ferric oxide catalyst. The ferric oxide catalyst was synthesized by sol gel technique from ferric chloride and...Oxidation of sulfide in aqueous solution by hydrogen peroxide was investigated in the presence of hydrated ferric oxide catalyst. The ferric oxide catalyst was synthesized by sol gel technique from ferric chloride and ammonia. The synthesized catalyst was characterized by Fourier transform infrared spectroscopy, X-Ray diffraction analysis, scanning electrom microscope and energy dispersive X-ray analysis. The catalyst was quite effective in oxidizing the sulfide by hydrogen peroxide. The effects of sulfide concentration, catalyst loading, H2O2 dosing and temperature on the kinetics of sulfide oxidation were investigated. Kinetic equations and activation energies for the catalytic oxidation reaction were calculated based on the experimental results.展开更多
A series of CaO samples were prepared by calcination of commercially available and synthesis of calcium salt precursors such as calcium acetate,carbonate,hydroxide and oxalate etc.CaO samples were found to be effectiv...A series of CaO samples were prepared by calcination of commercially available and synthesis of calcium salt precursors such as calcium acetate,carbonate,hydroxide and oxalate etc.CaO samples were found to be effective for the epoxidation of styrene using hydrogen peroxide as an oxidant in the presence of acetonitrile.To determine the influence of the physicochemical properties and surface basicity on the catalytic activity,the prepared CaO samples were characterized using thermogravimetry(TG),X-ray diffraction(XRD),scanning electron microscopy(SEM),N2-adsorption and temperature-programmed desorption of CO2(CO2-TPD).The results indicate that the amounts of very strong basic sites and high basicity strength on CaO sample are key factors for its excellent catalytic performance.In contrast,the surface area,porosity and the surface structure of CaO sample have a relatively minor effect on the catalytic activity.CaO sample,obtained by the decomposition of Ca(OH)2,prepared by precipitating calcium nitrate with sodium hydroxide in ethylene glycol solution,exhibits the highest amount of very strong basic sites and stronger strength of basic sites,and therefore it catalyses the epoxidation of styrene with the highest rate among the tested CaO samples.Under the selected reaction conditions,the selectivity of 97.5% to styrene oxide at a conversion in excess of 99% could be obtained.展开更多
Hydrogen peroxide(H_2O_2) and free radicals cause oxidative stress, which induces cellular injuries, metabolic dysfunction, and even cell death in various clinical abnormalities. Fullerene(C_(60)) is critical for scav...Hydrogen peroxide(H_2O_2) and free radicals cause oxidative stress, which induces cellular injuries, metabolic dysfunction, and even cell death in various clinical abnormalities. Fullerene(C_(60)) is critical for scavenging oxygen free radicals originated from cell metabolism, and reduced glutathione(GSH) is another important endogenous antioxidant. In this study, a novel water-soluble reduced glutathione fullerene derivative(C_(60)-GSH) was successfully synthesized, and its beneficial roles in protecting against H_2O_2-induced oxidative stress and apoptosis in cultured HEK 293 T cells were investigated. Fourier Transform infrared spectroscopy and 1H nuclear magnetic resonance were used to confirm the chemical structure of C_(60)-GSH. Our results demonstrated that C_(60)-GSH prevented the reactive oxygen species(ROS)-mediated cell damage. Additionally, C_(60)-GSH pretreatment significantly attenuated H_2O_2-induced superoxide dismutase(SOD) consumption and malondialdehyde(MDA) elevation. Furthermore, C_(60)-GSH inhibited intracellular calcium mobilization, and subsequent cell apoptosis via bcl-2/bax-caspase-3 signaling pathway induced by H_2O_2 stimulation in HEK 293 T cells. Importantly, these protective effects of C_(60)-GSH were superior to those of GSH. In conclusion, these results suggested that C_(60)-GSH has potential to protect against H_2O_2-induced cell apoptosis by scavenging free radicals and maintaining intracellular calcium homeostasis without evident toxicity.展开更多
Because phenolic compounds are toxic for methanogenic bacteria many problems concerning the high toxicity and biodegradability of the olive oil mill wastewater (OMW) have been encountered during anaerobic treatments o...Because phenolic compounds are toxic for methanogenic bacteria many problems concerning the high toxicity and biodegradability of the olive oil mill wastewater (OMW) have been encountered during anaerobic treatments of this effluent. In this work, we try to develop a new catalytic process for the degradation of phenolic compounds, producing less toxic OMW for methanogenic bacteria, facilitating the anaerobic digestion. This process consists of an oxidative reaction using copper supported on alumina pillared clay in presence of a photocatalytic system (H2O2 with UV light). Preliminary results showed that the use of the copper supported catalyst in presence of 0.88% H2O2 (v/v) allows after 2 h colour reduction (25%), significant abatement of total organic carbon (40%), and important removal of polyphenolic compounds (63%) especially those of high molecular mass and subsequently decreases the OMW toxicity from 100% to 70%. This catalytic pre-treatment process of OMW was efficient for anaerobic digestion.展开更多
The oxidative desulfurization of a real refinery feedstock (i.e.,non-hydrotreated kerosene with total sulfur mass content of 0.16%) with a mixture of hydrogen peroxide and acetic acid was studied.The influences of var...The oxidative desulfurization of a real refinery feedstock (i.e.,non-hydrotreated kerosene with total sulfur mass content of 0.16%) with a mixture of hydrogen peroxide and acetic acid was studied.The influences of various operating parameters including reaction temperature (T),acid to sulfur molar ratio (nacid/nS),and oxidant to sulfur molar ratio (nO/nS) on the sulfur removal of kerosene were investigated.The results revealed that an increase in the reaction temperature (T) and nacid/nS enhances the sulfur removal.Moreover,there is an optimum nO/nS related to the reaction temperature and the best sulfur removal could be obtained at nO/nS=8 and 23 for the reaction temperatures of 25 and 60°C,respectively.The maximum observed sulfur removal in the present oxidative desulfurization system was 83.3%.展开更多
This study reports an investigation into the degradation of 2,4-dichlorophenoxyacetic acid in bubble contactor column by O3/H2O2 process, which is widely used as a principal advanced oxidation process. The degradation...This study reports an investigation into the degradation of 2,4-dichlorophenoxyacetic acid in bubble contactor column by O3/H2O2 process, which is widely used as a principal advanced oxidation process. The degradation of 2,4-dichlorophenoxyacetic acid was studied under different H2O2/O3 molar ratio and pH value. Meanwhile, TOC removal was investigated both in distilled water and tap water. The influences of ozone transfer and consumed hydrogen peroxide were also discussed. The degradation products and oxidation intermediates were identified by GC-MS and LC-MS. A possible reaction mechanism was thus proposed.展开更多
The extensive use of nanoparticles(NPs)in diverse applications causes their localization to aquatic habitats,affecting the metabolic products of primary producers in aquatic ecosystems,such as algae.Synthesized calciu...The extensive use of nanoparticles(NPs)in diverse applications causes their localization to aquatic habitats,affecting the metabolic products of primary producers in aquatic ecosystems,such as algae.Synthesized calcium oxide nanoparticles(CaO NPs)are of the scarcely studied NPs.Thus,the current work proposed that the exposure to CaO NPs may instigate metabolic pathway to be higher than that of normally growing algae,and positively stimulate algal biomass.In this respect,this research was undertaken to study the exposure effect of CaO NPs(0,20,40,60,80,and 100μg mL^(−1))on the growth,photosynthesis,respiration,oxidative stress,antioxidants,and lipid production of the microalga Coccomyxa chodatii SAG 216-2.The results showed that the algal growth concomitant with chlorophyll content,photosynthesis,and calcium content increased in response to CaO NPs.The contents of biomolecules such as proteins,amino acids,and carbohydrates were also promoted by CaO NPs with variant degrees.Furthermore,lipid production was enhanced by the applied nanoparticles.CaO NPs induced the accumulation of hydrogen peroxide,while lipid peroxidation was reduced,revealing no oxidative behavior of the applied nanoparticles on alga.Also,CaO NPs have a triggering effect on the antioxidant enzymes such as superoxide dismutase,catalase,ascorbate peroxidase,and guaiacol peroxidase.The results recommended the importance of the level of 60μg mL^(−1) CaO NPs on lipid production(with increasing percentage of 65%compared to control)and the highest dry matter acquisition of C.chodatii.This study recommended the feasibility of an integrated treatment strategy of CaO NPs in augmenting biomass,metabolic up-regulations,and lipid accumulation in C.chodatii.展开更多
[Objectives] To study the effects of Roudoukou-8 San extract on hydrogen peroxide( H_2O_2) induced cardiomyocyte injury of rats and explore its action mechanism. [Methods] The cardiomyocytes of neonatal rats were isol...[Objectives] To study the effects of Roudoukou-8 San extract on hydrogen peroxide( H_2O_2) induced cardiomyocyte injury of rats and explore its action mechanism. [Methods] The cardiomyocytes of neonatal rats were isolated and cultured,and the H_2O_2 induced cardiomyocyte injury model was established. Methyl thiazolyl tetrazolium( MTT) assay was used to detect the protective effects of Roudoukou-8 San extract on H_2O_2 induced cardiomyocyte. The effects of Roudoukou-8 San on cardiomyocyte morphology were observed under inverted microscope. The contents of lactate dehydrogenase( LDH),creatine kinase( CK) and aspartate aminotransferase( AST) in cell culture medium were determined by automatic biochemical instrument; the levels of malondialdehyde( MDA),superoxide dismutase( SOD) and nitric oxide( NO) in the cells were detected by kit method. The apoptotic morphology of cardiomyocytes was observed by Hoechst fluorescence staining.Cell apoptosis were measured by Annexin V and PI double staining and flow cytometer. [Results]100 μmol/L of H_2O_2 acting 2 h could cause about 50% of cardiomyocyte injury. H_2O_2 model group showed increased cell gap,decreased cell count,cell cytoplasmic vacuoles and other obvious damages. Compared with H_2O_2 model group,in Roudoukou-8 San extract dose groups,cardiomyocyte morphology showed different degrees of improvement,Roudoukou-8 San extract can significantly reduce the content of LDH,CK and AST in H_2O_2 injured myocardial cell culture solution,significantly reduce content of MDA and NO in H_2O_2 injured myocardial cells,increase the SOD activity,and significantly inhibit the apoptosis of H_2O_2 injured myocardial cells. [Conclusions]Through improving the cell survival status,increasing the cell viability,reducing oxidative stress injury,inhibiting inflammatory responses,and inhibiting apoptosis,Roudoukou-8 San extract can improve the state of H_2O_2 induced cardiomyocyte injury,so as to protect H_2O_2 injured myocardial cells.展开更多
基金supported by the National Nature Science Foundation of China (J1210060, 21143002)
文摘Sulfonated carbon as a strong and stable solid acid catalyst exhibited excellent catalytic performance in various acid-catalyzed reactions. Here, sulfonated carbon, as catalyst for oxidation reaction, was prepared via the carbonization of starch followed by sulfonation with concentrated sulfuric acid. N2 physisorption, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray fluorescence and acid-base titration were used to characterize the obtained materials. The catalytic activity of sulfonated carbon was studied in the oxidation of aldehydes to carboxylic acids using 30 wt% H2O2 as oxidant. This oxidation protocol works well for various aldehydes including aromatic and aliphatic aldehydes. The sulfonated carbon can be recycled for three times without obvious loss of activity.
文摘Sn-aniline complex was prepared by a simple procedure.Cyclic and acyclic ketones were oxidized into lactones or esters with very high selectivity and yield with 30% hydrogen peroxide in the presence of Sn-aniline complex.
基金Supported by the National Natural Science Foundation of China(Nos.20502017and20072024)the Teaching and ResearchAward Program for Outstanding Young Teachers in Higher Education Institutions of Ministry of Education,Chinathe ScienceFoundation for Young Teachers of Sichuan University.
文摘The selective catalytic oxidation of toluene with hydrogen peroxide over V-Mo-based catalysts under mild conditions was studied.The promotion effect of Mo on the catalysts was studied with V/Al2O3 and Mo/Al2O3 as reference samples.The catalysts were characterized by XRD,TPR,and XPS techniques.The results show that the addition of Mo to V/Al2O3 may change the distribution of V species on Al2O3 surface.Over V-Mo/Al2O3 catalyst,highly dispersed amorphous V species facilitates benzaldehyde formation,and crystalline V2O5 species increases the conversion of toluene but decreases the selectivity to benzaldehyde,while AlVMoO7 species favors both the conversion of toluene and the formation of cresols.The yield of benzaldehyde depends remarkably on the surface O/Al and Mo/V atomic ratios,and gets to a maximum value of 13.2% with a selectivity of 79.5% at an O/Al atomic ratio of 3.0 and Mo/V atomic ratio of 0.7.
文摘An investigation on the process of ozone combined with hydrogen peroxi de and ultraviolet radiation has been carried out in order to establish the kine tics for photochemical oxidation of polyacrylamide (PAM) in aqueous solution. Ef fects of operating parame- ters, including initial PAM concentration, dosages of ozone and hydrogen peroxide, UV radiation and pH value on the photochemical oxi dation of PAM, have been studied. There was an increase in photochemical oxidati on rate of PAM with increasing of dosages of O3, H2O2 and ultraviolet radiation. Upon increasing of the initial PAM concentration, the photochemical oxidation r ate of PAM decreased. Slight effect of pH value on the photochemical oxidation r ate of PAM was observed in the experiments. The kinetics equation for the photoc hemical oxidation of PAM by the system has been established.
基金the financial support(Research Council Grant)provided by Isfahan University of Technology(Iran).
文摘A series of CoPd/KIT-6 bimetallic catalysts with various Co:Pd molar ratios at different calcination temperatures were prepared and used for the direct synthesis of H_(2)O_(2) from H_(2) and O_(2).These catalysts were characterized by nitrogen adsorption-desorption,low and wide-angle X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM),scanning electron microscopy(SEM),elemental mapping and energy-dispersive X-ray(EDX)methods.It was found that the particle size,electronic interactions,morphology,and textural properties of these catalysts as well as their catalytic activity in the reaction of H_(2) with O_(2) were affected by Co addition and different calcination temperatures.Also,the results showed that while the H_(2)O_(2) selectivity depends on Pd^(2+) species,the H_(2) conversion is related to Pd0 active sites.Among these catalysts,CoPd/KIT-6 calcined at 350℃(CoPd/KIT-350 catalyst)showed the best catalytic activity with 50%of H_(2)O_(2) selectivity and 51%conversion of H_(2).
基金support from the National Natural Science Foundation of China(U19B6002)National Key Research and Development Program of China(2016YFB0301600).
文摘Basic organic chemicals and high value–added products are mainly produced by hydrocarbon nitridation and oxidation.However,several drawbacks limit the application of the traditional oxidation and nitridation technologies in the future,such as complex processes,poor intrinsic safety,low atom utilization,and serious environmental pollution.The green nitridation and oxidation technologies are urgently needed.Hydrogen peroxide,a well–known green oxidant,is widely used in green hydrocarbon oxidation and nitridation.But its industrial production in China adopts fixed–bed technology,which is fall behind slurry–bed technology adopted by advanced foreign chemical companies,limiting the development of hydrogen peroxide industry and green hydrocarbon nitridation or oxidation industry.This article reviews the industrial production technologies of hydrogen peroxide and basic organic chemicals such as caprolactam,aniline,propene oxide,epichlorohydrin,phenol,and benzenediol,especially introduces the green production technologies of basic organic chemicals related with H_(2)O_(2).The article also emphasis on the efforts of Chinese researchers in developing its own slurry–bed technology of hydrogen peroxide production,and corresponding green hydrocarbon nitridation or oxidation technologies with hydrogen peroxide.Compared with traditional nitridation or oxidation technologies,green production technologies of caprolactam,propene oxide,epichlorohydrin,and benzenediol with hydrogen peroxide promote the nitrogen atom utilization from 60%to near 100%and the carbon atom utilization from 80%to near 100%.The waste emissions and environmental investments are reduced dramatically.Technological blockade against the green chemical industry of China are partially broken down,and technological upgrade in the chemical industry of China is guaranteed.
基金supported by Skin Research Center,Shahid Beheshti University of Medical Sciences,and this manuscript is based on PhD thesis(No.9409)of Dr.Marjan Khazan
文摘Objective:To evaluate the biomarkers of oxidative stress in herpes zoster patients compared with control subjects.Methods:This study compared the nitric oxide(NO),hydrogen peroxide(H2 O2),malon dialdehyde,uric acid,and bilirubin levels between 43 herpes zoster patients and 47 age-matched control subjects.The area under the curve of the receiver operating characteristic curve was performed to evaluate the final logistic regression model.Results:The significant differences were observed in the serum levels of NO,H2 O2,and malondialdehyde between the case and the control groups(P<0.001).However,no statistical differences were found in both uricacid and bilirubin levels between the groups.Additionally,the raised oxidant biomarkers were strongly associated with increased disease severity(P<0.001).Multiple logistic regression analysis with the highest area under the curve[0.98(95%CI 0.95-1.00)]and the minimum number of variables showed that high levels of NO(OR 1.24;95%CI 1.06-1.46;P=0.008)and H2 O2(OR 1.25;95%CI 1.09-1.43;P=0.001)were associated with herpes zoster.Conclusions:High levels of NO and H2 O2 were observed in patients with herpes zoster.Increased NO and H2 O2 levels might be associated with herpes zoster,which needs to be confirmed by further studies.
基金supported by a grant from the Higher Education Commission,Islamabad-Pakistan(NRPU 20-4386)。
文摘Background:Hepatocellular carcinoma(HCC)has a high incidence and mortality that epitomizes one of the prominent causes of cancer-related death globally.Novel therapeutic approaches are therefore required.Reactive oxygen species(ROS)are necessary for maintaining cell cycle.Although ROS is involved in HCC progression,hydrogen peroxide(H2O2)has anti-proliferative effect on HCC.Method:HCC Huh-7 cells were cultured and incubated with various concentrations of H2O2.Paraoxonase activity,levels of malondialdehyde,glutathione and protein oxidation were measured in treated and untreated Huh-7 cells.Furthermore,untreated and treated Huh-7 cells were subjected to two dimensional gel electrophoresis and identified protein spots which were differentially expressed by LC-MS/MS analysis.q RT-PCR was performed to validate the identified proteins.Results:H2O2 depleted glutathione(GSH)with the concomitant up-regulation of GSTP1 and Prx2.H2O2 also increased malondialdehyde and protein oxidation,decreased the activity of paraoxonase in Huh-7 cells.Conclusion:H2O2 could be used as a novel therapeutic agent that might be beneficial in inducing cell cytotoxicity and hence suppress HCC proliferation.
文摘The green and effective Baeyer-Villiger oxidation reaction of cyclohexanone for preparing ε-caprolactone is of particular importance in the synthesis of new polymer materials. We have discussed here several mechanism types of Baeyer-Villiger oxidation of cyclohexanone with H2O2 in different reaction systems. Five main types have been addressed, i. e.: (1) the non-catalyzed reaction type, where the C=O of ketones is activated by H+, which is electrolytically dissociated from H2O2 and H2O, to improve the capability of C=O group for accepting the electron pairs; (2) the thermally activated radical reaction type, where the Criegee intermediate is produced via two steps of radical reaction with ·OH attack, with much more hydroxyl radicals being excited in the presence of TS-1 zeolite; (3) the Brnsted acid catalysis reaction type, where both O-O moiety and C=O group could be activated by Brnsted acid; (4) the solid Lewis acid catalyzed C=O of the substrate activation reaction type through enhancing the donor-acceptor interaction between the antibonding π*C=O orbital of cyclohexanone and HOMO of Sn-containing zeolites; and (5) the solid Lewis acid catalyzed H2O2 to form Me-OOH oxidative species by converting the highest occupied molecular orbital (HOMO) of Ti-OOH into a singly occupied molecular orbital (SOMO), making the O-O group highly electrophilic to attack the C=O of cyclohexanone during the Baeyer-Villiger oxidation process. In the end, we have also compared the different mechanisms and put forward our opinions on the development direction of catalytic materials aiming at eco-friendly Baeyer-Villiger oxidation of cyclohexanone in the years to come.
文摘Oxidation of sulfide in aqueous solution by hydrogen peroxide was investigated in the presence of hydrated ferric oxide catalyst. The ferric oxide catalyst was synthesized by sol gel technique from ferric chloride and ammonia. The synthesized catalyst was characterized by Fourier transform infrared spectroscopy, X-Ray diffraction analysis, scanning electrom microscope and energy dispersive X-ray analysis. The catalyst was quite effective in oxidizing the sulfide by hydrogen peroxide. The effects of sulfide concentration, catalyst loading, H2O2 dosing and temperature on the kinetics of sulfide oxidation were investigated. Kinetic equations and activation energies for the catalytic oxidation reaction were calculated based on the experimental results.
基金supported by the National Natural Science Foundation of China (No.21173110)
文摘A series of CaO samples were prepared by calcination of commercially available and synthesis of calcium salt precursors such as calcium acetate,carbonate,hydroxide and oxalate etc.CaO samples were found to be effective for the epoxidation of styrene using hydrogen peroxide as an oxidant in the presence of acetonitrile.To determine the influence of the physicochemical properties and surface basicity on the catalytic activity,the prepared CaO samples were characterized using thermogravimetry(TG),X-ray diffraction(XRD),scanning electron microscopy(SEM),N2-adsorption and temperature-programmed desorption of CO2(CO2-TPD).The results indicate that the amounts of very strong basic sites and high basicity strength on CaO sample are key factors for its excellent catalytic performance.In contrast,the surface area,porosity and the surface structure of CaO sample have a relatively minor effect on the catalytic activity.CaO sample,obtained by the decomposition of Ca(OH)2,prepared by precipitating calcium nitrate with sodium hydroxide in ethylene glycol solution,exhibits the highest amount of very strong basic sites and stronger strength of basic sites,and therefore it catalyses the epoxidation of styrene with the highest rate among the tested CaO samples.Under the selected reaction conditions,the selectivity of 97.5% to styrene oxide at a conversion in excess of 99% could be obtained.
基金supported by the Nature Science Foundation Committee Projects of China(No.30470425)
文摘Hydrogen peroxide(H_2O_2) and free radicals cause oxidative stress, which induces cellular injuries, metabolic dysfunction, and even cell death in various clinical abnormalities. Fullerene(C_(60)) is critical for scavenging oxygen free radicals originated from cell metabolism, and reduced glutathione(GSH) is another important endogenous antioxidant. In this study, a novel water-soluble reduced glutathione fullerene derivative(C_(60)-GSH) was successfully synthesized, and its beneficial roles in protecting against H_2O_2-induced oxidative stress and apoptosis in cultured HEK 293 T cells were investigated. Fourier Transform infrared spectroscopy and 1H nuclear magnetic resonance were used to confirm the chemical structure of C_(60)-GSH. Our results demonstrated that C_(60)-GSH prevented the reactive oxygen species(ROS)-mediated cell damage. Additionally, C_(60)-GSH pretreatment significantly attenuated H_2O_2-induced superoxide dismutase(SOD) consumption and malondialdehyde(MDA) elevation. Furthermore, C_(60)-GSH inhibited intracellular calcium mobilization, and subsequent cell apoptosis via bcl-2/bax-caspase-3 signaling pathway induced by H_2O_2 stimulation in HEK 293 T cells. Importantly, these protective effects of C_(60)-GSH were superior to those of GSH. In conclusion, these results suggested that C_(60)-GSH has potential to protect against H_2O_2-induced cell apoptosis by scavenging free radicals and maintaining intracellular calcium homeostasis without evident toxicity.
文摘Because phenolic compounds are toxic for methanogenic bacteria many problems concerning the high toxicity and biodegradability of the olive oil mill wastewater (OMW) have been encountered during anaerobic treatments of this effluent. In this work, we try to develop a new catalytic process for the degradation of phenolic compounds, producing less toxic OMW for methanogenic bacteria, facilitating the anaerobic digestion. This process consists of an oxidative reaction using copper supported on alumina pillared clay in presence of a photocatalytic system (H2O2 with UV light). Preliminary results showed that the use of the copper supported catalyst in presence of 0.88% H2O2 (v/v) allows after 2 h colour reduction (25%), significant abatement of total organic carbon (40%), and important removal of polyphenolic compounds (63%) especially those of high molecular mass and subsequently decreases the OMW toxicity from 100% to 70%. This catalytic pre-treatment process of OMW was efficient for anaerobic digestion.
基金Supported by the R&D center of Esfahan refinery (Esfahan,Iran)the technical supports of central laboratory of Esfahan Refinery for total sulfur analysis
文摘The oxidative desulfurization of a real refinery feedstock (i.e.,non-hydrotreated kerosene with total sulfur mass content of 0.16%) with a mixture of hydrogen peroxide and acetic acid was studied.The influences of various operating parameters including reaction temperature (T),acid to sulfur molar ratio (nacid/nS),and oxidant to sulfur molar ratio (nO/nS) on the sulfur removal of kerosene were investigated.The results revealed that an increase in the reaction temperature (T) and nacid/nS enhances the sulfur removal.Moreover,there is an optimum nO/nS related to the reaction temperature and the best sulfur removal could be obtained at nO/nS=8 and 23 for the reaction temperatures of 25 and 60°C,respectively.The maximum observed sulfur removal in the present oxidative desulfurization system was 83.3%.
基金The National Natural Science Foundation of China (No. 50378028)
文摘This study reports an investigation into the degradation of 2,4-dichlorophenoxyacetic acid in bubble contactor column by O3/H2O2 process, which is widely used as a principal advanced oxidation process. The degradation of 2,4-dichlorophenoxyacetic acid was studied under different H2O2/O3 molar ratio and pH value. Meanwhile, TOC removal was investigated both in distilled water and tap water. The influences of ozone transfer and consumed hydrogen peroxide were also discussed. The degradation products and oxidation intermediates were identified by GC-MS and LC-MS. A possible reaction mechanism was thus proposed.
文摘The extensive use of nanoparticles(NPs)in diverse applications causes their localization to aquatic habitats,affecting the metabolic products of primary producers in aquatic ecosystems,such as algae.Synthesized calcium oxide nanoparticles(CaO NPs)are of the scarcely studied NPs.Thus,the current work proposed that the exposure to CaO NPs may instigate metabolic pathway to be higher than that of normally growing algae,and positively stimulate algal biomass.In this respect,this research was undertaken to study the exposure effect of CaO NPs(0,20,40,60,80,and 100μg mL^(−1))on the growth,photosynthesis,respiration,oxidative stress,antioxidants,and lipid production of the microalga Coccomyxa chodatii SAG 216-2.The results showed that the algal growth concomitant with chlorophyll content,photosynthesis,and calcium content increased in response to CaO NPs.The contents of biomolecules such as proteins,amino acids,and carbohydrates were also promoted by CaO NPs with variant degrees.Furthermore,lipid production was enhanced by the applied nanoparticles.CaO NPs induced the accumulation of hydrogen peroxide,while lipid peroxidation was reduced,revealing no oxidative behavior of the applied nanoparticles on alga.Also,CaO NPs have a triggering effect on the antioxidant enzymes such as superoxide dismutase,catalase,ascorbate peroxidase,and guaiacol peroxidase.The results recommended the importance of the level of 60μg mL^(−1) CaO NPs on lipid production(with increasing percentage of 65%compared to control)and the highest dry matter acquisition of C.chodatii.This study recommended the feasibility of an integrated treatment strategy of CaO NPs in augmenting biomass,metabolic up-regulations,and lipid accumulation in C.chodatii.
基金Supported by Project of National Natural Science Foundation(81360678)Program for Young Talents of Science and Technology in Universities of Inner Mongolia(NJYT-17-B29)Program of Health and Family Planning Commission of Inner Mongolia(201702059)
文摘[Objectives] To study the effects of Roudoukou-8 San extract on hydrogen peroxide( H_2O_2) induced cardiomyocyte injury of rats and explore its action mechanism. [Methods] The cardiomyocytes of neonatal rats were isolated and cultured,and the H_2O_2 induced cardiomyocyte injury model was established. Methyl thiazolyl tetrazolium( MTT) assay was used to detect the protective effects of Roudoukou-8 San extract on H_2O_2 induced cardiomyocyte. The effects of Roudoukou-8 San on cardiomyocyte morphology were observed under inverted microscope. The contents of lactate dehydrogenase( LDH),creatine kinase( CK) and aspartate aminotransferase( AST) in cell culture medium were determined by automatic biochemical instrument; the levels of malondialdehyde( MDA),superoxide dismutase( SOD) and nitric oxide( NO) in the cells were detected by kit method. The apoptotic morphology of cardiomyocytes was observed by Hoechst fluorescence staining.Cell apoptosis were measured by Annexin V and PI double staining and flow cytometer. [Results]100 μmol/L of H_2O_2 acting 2 h could cause about 50% of cardiomyocyte injury. H_2O_2 model group showed increased cell gap,decreased cell count,cell cytoplasmic vacuoles and other obvious damages. Compared with H_2O_2 model group,in Roudoukou-8 San extract dose groups,cardiomyocyte morphology showed different degrees of improvement,Roudoukou-8 San extract can significantly reduce the content of LDH,CK and AST in H_2O_2 injured myocardial cell culture solution,significantly reduce content of MDA and NO in H_2O_2 injured myocardial cells,increase the SOD activity,and significantly inhibit the apoptosis of H_2O_2 injured myocardial cells. [Conclusions]Through improving the cell survival status,increasing the cell viability,reducing oxidative stress injury,inhibiting inflammatory responses,and inhibiting apoptosis,Roudoukou-8 San extract can improve the state of H_2O_2 induced cardiomyocyte injury,so as to protect H_2O_2 injured myocardial cells.