Study of the role of alkaline sodium additive in selective hydrogenation of phenol

The selective hydrogenation of phenol to cyclohexanone is an important process in the chemical industry.However,achieving high selectivity at high conversion rates is highly challenging,particularly under continuous reaction conditions.Here,we found that the presence of Na alkaline additives(NaX,X=CO3^2–,HCO^3–,or OH^–)on Pd/Al2O3 not only promoted the phenol conversion from 8.3%to>99%but also increased the cyclohexanone selectivity from 89%to>97%during the continuous hydrogenation of phenol on a fixed bed reactor.After 1200 h of continuous reaction,no activity or selectivity attenuation was observed and the turnover number was approximately 2.9×10^5.Density functional theory calculations,spectroscopic,and dynamics studies demonstrated that the addition of NaX greatly promoted phenol adsorption and hydrogen activation,thereby improving catalytic activity.Simultaneously,the formation of a“-C=O-Na-”intermediate inhibited the excessive hydrogenation and intermolecular coupling of cyclohexanone,leading to high selectivity.

在3,4-二羟基肉桂酸介质中以多壁碳纳米管为传感器电催化检测L-半胱氨酸(英文)

A highly sensitive electrochemical sensor was prepared for the determination of L-cysteine using a modified multiwall carbon nanotubes paste electrode in the presence of 3,4-dihydroxycinnamic acid(3,4-DHCA) as a mediator, based on an electrocatalytic process. The results indicate that the electrode is electrocatalytically efficient for the oxidation of L-cysteine in the presence of 3,4-DHCA. The interaction between the mediator and L-cysteine can be used for its sensitive and selective determination. Using chronoamperometry, the catalytic reaction rate constant was calculated to be 2.37 × 102 mol–1 L s–1. The catalytic peak current was linearly dependent on the L-cysteine concentration in the range of 0.4–115 μmol/L. The detection limit obtained by linear sweep voltammetry was 0.25 μmol/L. Finally, the modified electrode was examined as a selective, simple, and precise new electrochemical sensor for the determination of L-cysteine in real samples.

Synthesis and Characterization of a Persistent Benzoanthracenyl Radical Derivative

A highly persistent benzoanthracenyl radical(BAR1)protected by five substituents at strategic positions is synthesized.BAR1 exhibited half-life time of 108 h in air-saturated solution,which allowed for detailed characterization in the solution.The combined experimental and theoretical study reveals the properties associated with its asymmetric structure and spin distribution.One-electron oxidation of BAR1 afforded stable cationic species BAR1+,whose structure is unambiguously determined by the NMR spectroscopy.

Definition of Binding Force of Molecular Orbital

Like many other properties of the molecular orbital (MO), such as energy level,electron negativity and charge distribution, the binding force of the molecular orbitalis regarded as an important physical concept to describe the binding property of themolecular orbital. The MO’s are divided into binding orbital, nonbinding orbital andantibinding orbital according to their respective binding effect. The binding charac-ter of an MO can be determined through the measurement of the changes in

Rauvolfia serpentina-Mediated Green Synthesis of CuO Nanoparticles and Its Multidisciplinary Studies

Copper oxide nanoparticles （CuO Nps） were successfully synthesized by solution combustion method using aqueous leaf extract of Rauvolfia serpentina as a fuel. The structure and morphology of the CuO nanoparticles （Nps） were characterized by powder X-ray diffraction （PXRD）, UV-visible spectroscopy （UV-visible）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, etc. The PXRD patterns reveal the formation of monoclinic phase with crystallite structure. SEM images indicate that the particles have sponge-like structure being highly porous and agglom- erated with large surface area. The average crystallite sizes were found to be in the range of 10-20 nm by Scherrer＇s method. The CuO Nps size was further confirmed by TEM. Further, CuO Nps exhibit good photocatalytic activity for the photodegradation of trypan blue dye, indicating that it acts as a promising semiconducting material. The antibacterial properties of CuO nanoparticles were investigated against pathogenic bacterial strains, namely Gram -ve Escherichia coli （NCIM-5051） and Pseudomonas desmolyticum （NCIM-2028） and Gram ＋ve bacteria Staphylococcus aureus （NCIM- 5022） using the agar well diffusion method.