A Facile Method for the Epoxidation of Cyclic Enone Catalyzed by tert-BuNH2 with 30% Hydrogen Peroxide as Oxidant

It was found that tert-BuNH_2 is an efficient catalyst for epoxidation of α,β-unsaturated ketones with 30% H_2O_2under mild conditions.For most of the cyclic unsaturated ketones used,moderate to excellent yields (45%—93%)were obtained within 24 h period.     

Effect of Cationic Surfactant on the Inhibition of Ligninase by Hydrogen Peroxide

The inhibition of lingninase by hydrogen peroxide in the presence of cationic surfactant CTAB was studied by kinetic speetrophotometdc technique. Results showed that addition of CTAB enhanced the inhibition by H202, but it did not alter the inhibition pattern and the inhibition constant changed little with theco-ncentration of CTAB. Modification of the enzymic protein by the surfactant monomer may be responsible for the above mentioned results.     

An Iron(III)-Monoamidate Complex Catalyst for Selective Hydroxylation of Alkane CH Bonds with Hydrogen Peroxide

Selective oxidation: The success of the title reaction is caused by the strong electron donation from the amidate moiety of the dpaq ligand to the iron center (dpaq=2-[bis(pyridin-2-ylmethyl)]amino-N-quinolin-8-yl-acetamidate). This process facilitates the O?O bond heterolysis of the intermediate Fe(III) OOH species to generate a selective oxidant without forming highly reactive hydroxyl radicals.     

Study on the Biomimetic Oxidation Catalyzed by the Model Compound of Cytochrome P-450(VI)——The Influence of Substituent x in T(x-p)PMn(Ⅲ)Cl on the Hydroxylation of Alkane

The influence of monosubstitution at phonyl rings in a series of T(x-P) PMn (Ⅲ)Cl (x = o , m , p-CH3, CH3O, Cl, Br, I, NO , o-NH2, p-(CH3)3C) on the biomimetic catalytic hydroxylation and chlorizaiton of cyclohexane with PhIO was studied. The yields of cyclohexanol and chlorocyclohexane increased with the electron-withdrawing ability of the substituent in this manganese complex. The fair linear correlations between the yields of cyclohexanol and para or ortho substituent constant are presented as:logYx/YH = 0.310p+0.03, logyx/YCH3 = 0.61σ0.07Es+0.05, But there are no linear correlations between the yields of chloro-cyclohexane and either para, ortho or meta substituent constants.     

Environmentally Benign Oxidation of Some Organic Sulfides with 34% Hydrogen Peroxide Catalyzed by Simple Heteropolyoxometalates

An environmentally benign oxygenation protocol was developed for selective oxidation of some types of aromatic and aliphatic sulfides in good to excellent yields utilizing 34% hydrogen peroxide catalyzed by simple heteropolyoxometalates in normal drinking water at room temperature. The catalysts could be recovered and reused for at least seven reaction cycles under the described reaction conditions without considerable loss of reactivity. This procedure introduced a new insight into the use of simple heteropolyanions as recoverable catalysts for the oxidation of organic sulfides by an environmentally acceptable protocol. Keywords     

C–C Bond Rupture in the Oxidation of Lower (C2–C6) Alcohols with Hydrogen Peroxide Mediated by Iron-Containing Compounds

C–C bond rupture upon the oxidation of alcohols in the Fe(ClO₄)₃+ H₂O₂system in aqueous acetonitrile at room temperature is found. The relative yield of the products of C–C bond rupture is 20–30% under standard conditions for C₂and C₃alcohols and decreases in the series C₂> C₃> C₄> C₆. The alkyl radical and carboxylic acid are the products of C–C bond rupture in alcohol oxidation. Cyclohexane is a competitive inhibiting agent for C–H bond oxidation in 1-propanol, and it does not affect the yield of the products of C–C bond rupture. When H₂O₂is replaced by tert-BuOOH, the fraction of the products of C–C bond rupture decreases by an order of magnitude. Our data suggest that a non-radical intermediate, likely Fe(III) hydroperoxo complex, is responsible for C–C bond rupture in alcohol under the reaction conditions.     

Effect of PANI–AC Composite on Electrochemical Synthesis of Hydrogen Peroxide by Alkaline H2–O2 Fuel Cell Reactor

Russian Journal of Electrochemistry - Effect of polyaniline on the oxygen reduction reaction during the electrochemical synthesis of H2O2 by an alkaline H2–O2 fuel cell reactor was...     

Selective Electrochemical Recognition of o-Phenylenediol by a Novel Calix[4]arene Derivative

A new type of calixarene-modified electrode has been prepared by directly coating the surface of a glassy carbon electrode with tetrahydrofuran solution containing 25,26,27,28-tetra-（3-amidino thiopropoxy）-5,11,17,23-tetratert-butylcalix[4]arene, and applied to the investigation of electrochemical behavior of phenylenediols. The results showed that the modified electrode could selectively recognize o-phenylenediol, making the over-potential of o-phenylenediol dropped and peak current increased greatly. The anodic peak current is proportional to the concentration of o-phenylenediol in the range of 1.0×10^-5-1.0×10^-4 mol·L^-1 with the detection limit （SIN=3） of 1.0×10^-7 mol·L^-1. The recognizing mechanism, including electrochemical process and binging sites, was also discussed using voltammetry.     

LaSrNiO_(4-λ) with K_2NiF_4 Strcture──A Highly Active Catalyst for Direct Decomposition of Nitrogen Monoxide

IntroductionThecatalyticremovalofnitrogenmonoxide(NO)fromexhaustgascouldbeperformedbyeitherreductionwithgaseousreductantordirectdecomposi-tion,formingharmlesscomponentsN2andO,.Atpresenttheformerisprefer-entiallyemployedinindustryandtheremovalofautomobileexhaust[l]thoughthelatterissimplerandcheaper.Thisisduetothefactthatuptodatenosuit-ablecatalystwithaconsistentlyhighactivityforthelatterhasbeenfound.IthasbeengenerallyacceptedthatthedesorptionofoxygengeneratedfromtheNOdecompositionontheactive…     

Dawson结构钼钒磷杂多化合物对苯酚过氧化氢羟化作用的研究

Ｄａｗｓｏｎ结构钼钒磷杂多化合物对苯酚过氧化氢羟化作用的研究于剑锋，杨宇，吴通好，孙家锺（吉林大学化学系理论化学研究所，长春，１３００２３）关键词Ｄａｗｓｏｎ结构钼钒磷杂多化合物，苯酚羟化，过氧化氢苯二酚（ＤＢＨ）是重要的化工原料．由芳香化合物羟化制...     

尖晶石型铁酸镉催化苯酚过氧化氢羟化作用的研究

尖晶石型铁酸镉催化苯酚过氧化氢羟化作用的研究于剑锋，杨宇，吴通好，孙家锺（吉林大学化学系理论化学研究所，长春，１３００２３）关键词尖晶石型铁酸镉，苯酚过氧化氢羟化，苯二酚由低浓度的Ｈ２Ｏ２羟化苯酚制苯二酚（ＤＢＨ）的研究已有许多报道［１～４］，但其催...     

羟基磷酸铜催化剂催化羟化苯酚动力学研究

利用初始反应速率动力学方法研究以过氧化氢为氧化剂.羟基磷酸铜为催化剂催化氧化苯酚的动力学.对催化剂的用量、过氧化氢和苯酚浓度以及温度的影响进行了仔细研究.反应物和催化剂对该反应都是一级的,表观活化能为12kJ/mol.在考虑到所有的吸附平衡后.给出了相应的动力学公式.     

含铜过渡金属水滑石类化合物对苯酚过氧化氢羟化的催化作用

合成了一系列二元、三元过渡金属水滑石类化合物, 并经XRD、IR进行了表征.苯酚过氧化氢羟化结果表明, 含铜水滑石类化合物对该反应有较高的催化活性, 并初步提出了反应机理.     

Electrochemical Study on Decomposition of Hydrogen Peroxide with Fe(II)

Decomposition of H₂O₂ with Fe²⁺ was studied with SnO₂ electrodes. By chronoamperometric and voltammetric techniques, the diffusion coefficients of Fe^3* and H ₂O₂ were estimated to be 5 × 10-₆ and 2 × 10^?5 cm²/s, respectively; the rate of decomposition of H₂O₂ with Fe²⁺ was proportional to [H₂O₂]^1/2·[Fe²⁺]² at a smaller concentration of Fe²⁺, but to [H₂O₂]^1/2·[Fe²⁺] when [Fe²⁺] was increased, indicating the formation of ferryl ion and the electron exchange between it and Fe²⁺ playing important roles. This catalytic decomposition. was dependent on pH; the maximum rate was observed to occur about pH = 1.5.     

Hydrogen bonds in 4-dihydroxymethylpyridinium 2,6-dichloro-4-nitrophenolate

The ionic adduct of 2,6-dichloro-4-nitrophenol with 4-formylpyridine (which transforms into 4-dihydroxymethylpyridine), crystallizes in the space group P2₁/c with a = 12.264(2), b = 6.730(1), c = 16.731(3) Å, β = 99.46(3)° and Z = 4. Relatively long N⁺---HO⁻ hydrogen bonds (R_N = 2.683(3) Å are formed with strongly asymmetric location of the H-atom. This is well reflected both in IR and UV-VIS spectra. One of the gem diol OH group is attached to the phenolate oxygen atom and the second is engaged in the formation of infinite polyanionic chains via O---HO hydrogen bonds between OH groups.     

Continuous Flow Reactor for Hydroxylation of Benzene to Phenol by Hydrogen Peroxide

The direct hydroxylation of benzene to phenol catalyzed by activated carbon-supported Fe (Fe/AC) in acetonitrile using H₂O₂ as the oxidant was studied in a continuous flow reactor. Results showed that the continuous operation could obtain high phenol yield of 28.1%, coupled with the turnover frequency of 3 h^-1, and high selectivity of 98% under mild condition. The catalyst was characterized by N₂ adsorption/desorption, Boehm titration, X-ray photoelectron spectra, and Fourier transform infrared spectroscopy. It was observed that iron may interact with the carboxyl group forming iron-carboxylate like species, which act as the active phase. The apparent activation energy obtained by fitting an Arrhenius model to the experimental data was 13.4 kJ/mol. The reaction order was calculated to be about 1, 0.2 for benzene and 0.7 for H₂O₂.     

Electrochemical Surface Structuring with Polyaniline Wrapped Hb for Hydrogen Peroxide Biosensing

Through the electrodeposition of aniline with hemoglobin (Hb) on zincoxide‐gold colloidal sols (ZnO‐AuNPs) modified indium oxide electrode, a hydrogen peroxide (H₂O₂) biosensor was constructed. Polyaniline (PANI) form a nano‐cage wrapped Hb, which provided a comfortable and stable site for the immobization of Hb. UV‐vis spectrum was employed to characterize Hb retained original structure in the resulting Hb‐PANI/ZnO‐AuNPs membrane. Electrochemical investigation of the biosensor showed a pair of well‐defined, quasi‐reversible redox peaks with E_pa= ‐0.139 V and E_pc = ‐0.238 V (vs. SCE) in 0.1 M pH 7.0 phosphate buffer solution at the scan rate of 100 mV/s. The biosensor displayed a fast response time (<3 s) and broad linear response to H₂O₂ in the range from 1.5 μM to 1.7 mM with a detection limit of 0.8 μM (S/N = 3).     

二氧化钛纳米颗粒/还原氧化石墨烯修饰玻碳电极在对硝基苯酚检测中的应用

本文报道了用二氧化钛纳米颗粒（TiO₂NPs）/还原氧化石墨烯（RGO）的复合物修饰玻碳电极检测微量对硝基苯酚（4-NP）的电化学方法. 本研究用扫描电子显微镜（SEM）对该复合材料形貌进行表征,用循环伏安法和交流阻抗谱对该复合物电极的电化学性能进行检测,表现出良好的电化学特性,采用差分脉冲伏安法对4-NP进行微量检测,结果令人满意,这主要得益于TiO2NPs/RGO复合物对4-NP有较高的催化活性,其电流峰值与浓度呈较高的线性关系,DPV的检测范围为10μmol·L^-1 ~ 350μmol·L^-1,检测限为0.13 μmol·L^-1. 与其他报道的一些电化学传感器相比,该传感器检测范围大,检测限低,且工作稳定,成本低,分析简单快速,具有很好的应用前景.     

Selective Oxidation of Toluene with Hydrogen Peroxide Catalyzed by V-Mo-based Catalyst

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.