共查询到20条相似文献,搜索用时 15 毫秒
1.
Petr Baldrian Tom Cajthaml Vra Merhautov Jií Gabriel Frantiek Nerud Pavel Stopka Martin Hrubý Milan J. Bene 《Applied catalysis. B, Environmental》2005,59(3-4):267-274
Chelating sorbents with 8-hydroxyquinoline (IVa), 8-hydroxyquinoline-5-sulfonic acid (IVb), and tris(2-aminoethyl)amine (VI) ligands immobilized on macroporous methacrylate matrix were prepared and saturated with Co(II), Cu(II), and Fe(II). All these chelates catalyze cleavage of H2O2 yielding highly reactive hydroxyl radicals. All were able to degrade by this mechanism polycyclic aromatic hydrocarbons (anthracene, benzo[a]pyrene and benzo[k]fluoranthene). The most effective catalysts IVa-Fe, IVb-Fe, and VI-Cu (25 mg with 100 μmol H2O2) performed complete decomposition of 33 μg anthracene and benzo[a]pyrene during one 7-day catalytic cycle at 25 °C. The fastest decomposition proceeded during the 1st day of incubation; 75% of anthracene and 74% of benzo[a]pyrene were decomposed by IVb-Co within the first 24 h. More than 25% decomposition within the 1st day was also achieved with IVb-Fe, VI-Cu, IVa-Cu, and VI-Co for anthracene and more than 30% benzo[a]pyrene was decomposed by IVb-Fe, VI-Cu, IVa-Cu, and IVb-Cu during the same period. 1,4-Anthracenedione was the main product of anthracene oxidation by all catalysts. The catalysts were stable at pH 2–11 depending on their structure and able to perform sequential catalytic cycles without regeneration. 相似文献
2.
《Catalysis communications》2007,8(10):1516-1520
The bis(maltolato)oxo complexes of vanadium(V) and vanadium(IV) both in a soluble form and anchored to chemically modified silica gel, when used in combination with pyrazine-2-carboxylic acid (PCA), catalyze the oxidation of benzene to phenol and alkanes to the corresponding alkyl hydroperoxides with H2O2 at 40–50 °C. Heterogenizing the complexes leads to changes in regioselectivity and bond selectivity parameters of the alkane oxidation, and this opens new routes to the enhancement of the selectivity in oxidation processes. 相似文献
3.
4.
Zhengpei Ye Zaihui Fu Sheng Zhong Fang Xie Xiaoping Zhou Fenglan Liu Dulin Yin 《Journal of Catalysis》2009,261(1):110-115
A series of hexadentate 8-quinolinolato manganese(III) complexes were synthesized and proven to own a distorted octahedral geometry via elemental analysis, solid UV–vis spectroscopy and Hartree–Fock/3-21G+ calculation. These Mn(III) complexes were found to be more efficient than their corresponding tetradentate 8-quinolinolato manganese(II) and salen-MnIIIOAc for the oxidation of alcohols in acetone medium, being due to their special hexadentate binding structures that could open an axial MnO bond to form the more active pentadentate structures in the presence of aqueous hydrogen peroxide, as supported by UV–vis spectra. The halogen substituents in ligand's aryl ring could significantly enhance the catalytic activities and 5-chloro-7-iodo-8-quinolinolato manganese(III) gave the highest turnover number (TON). A reasonable mechanism for the present catalytic system was proposed. 相似文献
5.
V2O5经甘油还原,再以邻苯二甲酸或其二钠盐溶液浸渍,制备了改性V2O5催化剂用于异丁香酚的过氧化氢氧化。运用FT-IR、紫外可见漫反射光谱(DR UV-Vis)、XRD等对催化剂进行了表征。结果表明,还原-浸渍法可以有效调变V2O5的价态与晶体结构从而提升其催化性能,其中以甘油在120 ℃ 还原V2O5所得前体浸渍邻苯二甲酸二钠所得催化剂 (PVO)-120性能较佳。考察了N,N-二甲基甲酰胺(DMF)等助剂、DMF用量和反应时间等对氧化反应的影响。最优反应条件为:以 (PVO)-120为催化剂,以DMF-CH3COCH3(20%,体积比)为介质,异丁香酚:H2O2=1∶2(摩尔比),20 ℃ 反应4 h,异丁香酚转化率可达87.3%,香草醛收率达到78.0%。 相似文献
6.
Valiollah Mirkhani Majid Moghadam Shahram Tangestaninejad Iraj Mohammadpoor-Baltork Nahid Rasouli 《Catalysis communications》2008,9(13):2171-2174
The catalytic activity of a hybrid compound [Fe(salen)-POM] (1) consisting of metallosalen moiety, [FeIII(salen)Cl], covalently linked to a Keggin type polyoxometalate, K8SiW11O39 (POM), in the oxidation of hydrocarbons with hydrogen peroxide was investigated. Reaction products were identified by gas chromatography and satisfactory yields were obtained. While, the Fe(salen)-POM catalyst showed high catalytic activity and product selectivity in the oxidation reactions, the metallosalen alone, [FeIII(salen)Cl], showed very poor catalytic activity in these reactions. The ability of various transition metal ions in this oxidation system was also investigated. Among a series of hybrid compounds, Fe(salen)-POM showed the highest activity. 相似文献
7.
8.
9.
水中多环芳烃(PAHs)的去除技术研究进展 总被引:2,自引:0,他引:2
《应用化工》2016,(5):962-966
从水中多环芳烃去除技术的角度,论述了物理法、化学法和生物法的应用现状和特点。为了更好的实现对水中多环芳烃的去除,各处理方法应该加强廉价高效降解材料和处理剂,降解过程和降解机理、复合降解方法以及对处理方法影响因素和条件的控制等方面的研究。 相似文献
10.
n-hexane conversion to hexanols and hexanones as well as the conversion of 2- and 3-hexanol to 2- and 3- hexanone, by reaction with aqueous hydrogen peroxide on titanium silicalite were the objects of kinetic investigations. The choice of these reactions is justified on the basis of an analysis of literature dealing with partial oxidation reactions performed on Ti sites in silica environments. The kinetic analysis based on equations derived using the mathematical theory of linear graphs allows several conclusions on the nature of surface intermediates and on the reaction mechanism. These conclusions are discussed in terms of the partial oxidation of organic materials by hydrogen peroxide over Ti catalysts. This review paper relies mostly on work by the authors and it intends to make an integrated presentation of the kinetics of some critically significant catalytic oxidation reactions. The content was the subject of a plenary lecture at the 5th symposium of the Romanian Catalysis Society. 相似文献
11.
J.-L. LiB.-H. Chen 《Chemical engineering science》2002,57(14):2825-2835
Solubilization of model polycyclic aromatic hydrocarbons (PAHs) by the readily biodegradable nonionic surfactants, Tergitol 15-S-X (X=7,9 and 12), consisting of mixtures of secondary ethoxylated alcohols was investigated at temperatures below their cloud points. Their solubilization capacities for phenanthrene were compared to those of three other commonly used surfactants, e.g. Triton X-100 and Tween 20 as well as Tween 80. Correlation between the micelle-water partition coefficients and the octanol-water partition coefficients in Tergitol 15-S-7 solutions indicated that the hydrophobicity of PAHs, i.e., their octanol-water partition coefficients, could be used in predicting the solubilization efficiency of PAHs by this nonionic surfactant. Effects of temperature and salinity on solubilization capacity of Tergitol 15-S-7 surfactant for phenanthrene were also investigated along with the micellar properties. The change in hydrodynamic radius and aggregation number of micelles with temperature was measured by the dynamic and static laser light scattering techniques. Results showed that increasing aggregation number and micellar size at higher temperature when cloud point is approached gives rise to the higher solubilization capacity of this surfactant. Effect of salinity on the enhancement of phenanthrene solubility was also discussed in terms of conformation changes in the micelles due to the possible coordination of sodium cations and oxygen atoms on the ethylene oxide groups of the surfactant. 相似文献
12.
Valiollah Mirkhani Majid Moghadam Shahram Tangestaninejad Iraj Mohammadpoor-Baltork Nahid Rasouli 《Inorganic chemistry communications》2007,10(12):1537-1540
The catalytic activity of a hybrid compound [Fe(salen)-POM] (1) consisting of Fe(III)(salen)Cl [H2salen = N,N′-bis(salicylidene)ethylenediamine] complex covalently linked to a Keggin type polyoxometalate, K8SiW11O39, (POM) was studied in the oxidation of various olefins in acetonitrile, using hydrogen peroxide as oxygen source. While, [Fe(salen)-POM] catalyst showed moderate to good catalytic activity and product selectivity in the oxidation reactions, the complex Fe(III)(salen)Cl showed poor catalytic activity in these reactions. The effect of other parameters such solvent, oxidant, temperature and the metal type in Schiff base complex were also investigated. 相似文献
13.
Labile iron(II) and iron(III) complexes {[FeII(bpy)22+]solv and [FeIII(bpy)23+]solv} in acetonitrile activate dioxygen for the oxidation of limonene to produce mainly carvone, carveol, limonene oxide, and
perillaldehyde. Iron(III) complex is reduced by the substrate to iron(II) one, which activates dioxygen. Probably the catalyst
interacts with substrate prior to the oxidation process. Perillaldehyde is likely formed directly from oxidation of methyl
group (not via alcohol). However, the aldehyde is also reduced to perillyl alcohol by the reduced form of the catalyst. 相似文献
14.
15.
《Catalysis communications》2003,4(11):603-608
Simple iron(III) salts activate hydrogen peroxide to oxidize 2-methylnaphthalene to 2-methyl-1-naphthol in glacial acetic acid. 2-Methyl-1-naphthol is then oxidized to 2-methyl-1,4-naphthoquinone by hydrogen peroxide without influence of the catalyst. This is in contrast to the previous reports, which excluded the formation of 2-methyl-1-naphthol as an intermediate product in the process of 2-methylnaphthalene oxidation to 2-methyl-1,4-naphthoquinone. The process, however, mimics the microbial conversion of 2-methylnaphthalene to 2-methyl-1,4-naphthoquinone. The presence of chloride in the system causes exclusively the formation of 2-methyl-1-chloronaphthalene. 相似文献
16.
《Inorganic chemistry communications》2003,6(3):249-251
The reaction of cis, cis-[PtII(9-fm)(dmpda)] (9-fm=9-fluorenylidenemalonate, dmpda=2,2-dimethyl-1,3-propanediamine) with hydrogen peroxide in ethyleneglycol produces cis,trans,cis-[PtIV(9-fm)(OCH2CH2OH)(OH)(dmpda)]. Its crystal structure shows that the local geometry around the platinum atom approximates a typical octahedral arrangement with the added OCH2CH2OH/OH ligands in trans coordination sites. The molecules are packed in a two-dimensional assembly via van der Waals interactions, where the hydrophobic fluorenyl groups are arranged on both faces of the assembly plate whereas the hydrophilic groups fill up the inner part of the plate. The compound bearing both “inorganic OH” and “organic OH” is a potential precursor for further various functionalizations. 相似文献
17.
Goldie SilvaSamantha Voth Paul SzymanskiErnest M. Prokopchuk 《Fuel Processing Technology》2011,92(8):1656-1661
In the presence of bis(acetylacetonato)oxovanadium(IV), dibenzothiophene was oxidized by hydrogen peroxide to form sulfoxide and sulfone products. The percentage of dibenzothiophene remaining after the oxidation and the ratio of these oxidation products, as determined by 1H NMR spectroscopy, was largely dependent on the solvent used. Reactions in acetonitrile consumed more than 99% of the dibenzothiophene in the reaction and yielded the sulfone as the major product. The efficacy of biphasic oxidations performed in heptane and acetonitrile were dependent on the ratio of acetonitrile to heptane with a higher proportion of acetonitrile resulting in greater consumption of dibenzothiophene. After multiple oxidations, all of the dibenzothiophene was removed from the heptane solution. 相似文献
18.
Manuel Len‐Camacho Isabel Viera‐Alcaide M. Victoria Ruiz‐Mndez 《European Journal of Lipid Science and Technology》2003,105(1):9-16
A detailed study of the efficacy of the bleaching process for elimination of polycyclic aromatic hydrocarbons in Spanish olive pomace oils has been carried out. For this purpose active carbon with bleaching earth was used as absorbent. The amount of benzo‐(α)‐pyrene was determined by reversed‐phase high‐performance liquid chromatography with a Fluorimetric detector. The use of exhausted filter‐cakes in countercurrent processes with a cake formed of active carbon and bleaching earth is very efficient for reducing the initial content of benzo‐(α)‐pyrene before the addition of fresh adsorbent, thus reducing the amounts of carbon and earth required. 相似文献
19.
《Catalysis communications》2011,12(15):1181-1184
This work describes the application of a multiphase system for the oxidation of alcohols to ketones or aldehydes, and the selective conversion of sulfides to sulfoxides or sulfones using Keggin-type heteropolyacids and hydrogen peroxide. Benzylic and secondary alcohols were oxidized to ketones or aldehydes at 70 °C in good yield and selectivity. Similarly, sulfides were converted to sulfoxides or sulfones at room temperature with high yields and selectivity. 相似文献