Progress in Processes and Catalysts for Dehydrogenation of Cyclohexanol to Cyclohexanone

The dehydrogenation of cyclohexanol to cyclohexanone is a crucial industrial process in the production of caprolactam and adipic acid, both of which serve as important precursors in nylon textiles. This endothermic reaction is constrained by thermodynamic equilibrium and involves a complex reaction network, leading to a heightened focus on catalysts and process design. Copper-based catalysts have been extensively studied and exhibit exceptional low-temperature catalytic performance in cyclohexanol dehydrogenation, with some being commercially used in the industry. This paper specifically concentrates on research advancement concerning active species, reaction mechanisms, factors influencing product selectivity, and the deactivation behaviors of copper-based catalysts. Moreover, a brief introduction to the new processes that break thermodynamic equilibrium via reaction coupling and their corresponding catalysts is summarized here as well. These reviews may off er guidance and potential avenues for further investigations into catalysts and processes for cyclohexanol dehydrogenation.

Reaction Process of Chromium Slag Reduced by Industrial Waste in Solid Phase

M, a particular industrial waste, was selected to detoxify chromium slag at a high temperature. The carbon remaining in M reduced Cr （ Ⅳ ） of Na2 CrO4 borne in the chromium slag to Cr （ Ⅲ ） in the solid phase reaction, and its thermodynamics and kinetics were studied. The reduction process of Na2CrO4 by carbon produced CO, whiCh＇was endothermic. Under the experimental condition, the apparent activation energy was 4. 41 kJ·mol^-1 , the＇apparent order of reaction for Na2 CrO4 was equal to one, and the partial pressure of CO was only 0.22 Pa at 1 330℃.

IN SITU PROCESSING OF Al_(2)O_(3) WHISKERS REINFORCED Ti-Al INTERMETALLIC COMPOSITES

In situ Al2O3 whiskers reinforced Ti-Al intermetallic composites were fabricated at ~1200℃ by reaction sintering of cold-consolidated fillets consisting mainly of Ti, Al, and different additives. The phases and microstructures of the sintered composites were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The process of synthesis was investigated using differential thermal analysis (DTA). The effects of processing parameters and additives on the microstructures of the composites and the development of whisker were examined. It is found that the morphology of the whisker is strongly influenced by the additives, the exothermal reaction process, and the processing parameters.

DBU-based CO2 absorption-mineralization system: Reaction process,feasibility and process intensification

Amine-based carbon dioxide(CO2)capture is still limited by high desorption energy consumption.Fixing CO2 into carbonate is a safer and more permanent method.In this work,calcium oxide(CaO)is introduced to perform chemical desorption instead of thermal desorption on 1,8-diazabicyclo[5.4.0]undec-7-ene(DBU)aqueous solution after CO2 absorption.The X-ray diffraction(XRD)patterns of solid products show the formation of calcite calcium carbonate(CaCO3),which prove the feasibility of this method.The effects of reaction temperature,reaction time and Ca2+/CO32-molar ratios on the related reactions in CO2 absorption-mineralization process and CaCO3 precipitation are discussed,and purer CaCO3 is obtained by ultrasonic treatment.The CaCO3 content can be increased to 95.8%and the CO2 desorption ratio can achieve 80%by 30 min ultrasonic dispersion treatment under the conditions(40℃,180 min,Ca2+/CO32-molar ratio=1.0).After five cycles,DBU aqueous solution shows stable CO2 absorption and mineralization ability.Fourier transform infrared spectroscopy(FT-IR)spectra of the reaction process also indicate the regeneration of the solvent.Compared with thermal desorption,this process is exothermic,almost without no additional heat.

The Process of TiB_2-Cu Composite Phase and Structure Formation during Combustion Synthesis

The reaction process of combustion synthesis for TiB2 -Cu was investigated in detail using combustion-wave arresting experiment, X-ray diffraction （ XRD ） analysis, SEM analysis and differential thermal analysis （ DTA ）. The XRD analysis results for the different parts of the quenched specimen show that TiCux intermetallic phase firstly forms with the propagation of combustion wave, and then Ti1.87 B50 and Ti3B4 metastable phases come forth due to the diffusion of B atoms and finally the stable TiB2 phase forms because of the continuous diffusion of B atoms. The formation of TiB2 phase is uot completed by one step, but undergoes several transient processes. The process of reaction synthesis for Ti-B-Cu ternary system can be divided into three main stages： melting of Cu and Ti , and the formation of Cu- Ti melt and few TiCux , TiBx intermetallic phases ; large numbers of TiCux intermetallic phases formation and some fine TiB2 particles precipitation ; and the TiB2 particles coarsening and the stable TiB2 and Cu two phases formation in the final product.

Progress and challenges of carbon-fueled solid oxide fuel cells anode

Carbon-fueled solid oxide fuel cells(CF-SOFCs)can electrochemically convert the chemical energy in carbon into electricity,which demonstrate both superior electrical efficiency and fuel utilisation compared to all other types of fuel cells.However,using solid carbon as the fuel of SOFCs also faces some challenges,the fluid mobility and reactive activity of carbon-based fuels are much lower than those of gaseous fuels.Therefore,the anode reaction kinetics plays a crucial role in determining the electrochemical performance of CF-SOFCs.Herein,the progress of various anodes in CF-SOFCs is reviewed from the perspective of material compositions,electrochemical performance and microstructures.Challenges faced in developing high performance anodes for CF-SOFCs are also discussed.

Self-assembled synthesis of oxygen-doped g-C3N4 nanotubes in enhancement of visible-light photocatalytic hydrogen

Currently,photocatalytic water splitting is regarded as promising technology in renewable energy generation.However,the conversion efficiency suffers great restriction due to the rapid recombination of charge carriers.Rational designed the structure and doping elements become important alternative routes to improve the performance of photocatalyst.In this work,we rational designed oxygen-doped graphitic carbon nitride(OCN)nanotubes derived from supermolecular intermediates for photocata lytic water splitting.The as prepared OCN nanotubes exhibit an outstanding hydrogen evolution rate of 73.84μmol h^(-1),outperforming the most of reported one dimensional(1D)g-C_(3)N_(4) previously.Due to the rational oxygen doping,the band structure of g-C_(3)N_(4) is meliorated,which can narrow the band gap and reduce the recombination rate of photogene rated carriers.Furthermore,the hollow nanotube structure of OCN also provide multiple diffuse reflection during photocata lytic reaction,which can significantly promote the utilization capacity of visible light and enhance the photocatalytic water splitting performance.It is believed that our work not only rationally controls the nanostructure,but also introduces useful heteroatom into the matrix of photocatalyst,which provides an effective way to design high-efficiency g-C_(3)N_(4) photocatalyst.

Advanced oxidation technology for H_2S odor gas using non-thermal plasma

Non-thermal plasma technology is a new type of odor treatment processing.We deal with H2Sfrom waste gas emission using non-thermal plasma generated by dielectric barrier discharge.On the basis of two criteria,removal efficiency and absolute removal amount,we deeply investigate the changes in electrical parameters and process parameters,and the reaction process of the influence of ozone on H2S gas removal.The experimental results show that H2S removal efficiency is proportional to the voltage,frequency,power,residence time and energy efficiency,while it is inversely proportional to the initial concentration of H2S gas,and ozone concentration.This study lays the foundations of non-thermal plasma technology for further commercial application.

Fabrication of an r-Al_2Ti intermetallic matrix composite reinforced with α-Al_2O_3 ceramic by discontinuous mechanical milling for thermite reaction

In this study, a powder mixture with an Al/TiO2 molar ratio of 10/3 was used to form an r-Al2Ti intermetallic matrix composite （IMC） reinforced with α-Al2O3 ceramic by a novel milling technique, called discontinuous mechanical milling （DMM） instead of milling and ignition of the produced thermite. The results of energy dispersive X-ray spectroscopy （EDX） and X-ray diffraction （XRD） of samples with varying milling time indicate that this fabrication process requires considerable mechanical energy. It is shown that Al2Ti-α-Al2O3 IMC with small grain size was produced by DMM after 15 h of ball milling. Peaks for γ-TLA1 as well as Al2Ti and Al2O3 are observed in XRD patterns after DMM followed by heat treatment. The microhardness of the DMM-treated composite produced after heat treatment was higher than Hv 700.

Reaction dynamics in the combustion synthesis system of Al-CrO_3-Al_2O_3-NaF-N_2-O_2

A new material with heat-resistant and adiabatic characteristics and high strength was prepared using the combustion synthesis method by mixed powders of CrO3, Al, Al2O3, and NaF in atmospheric gas. The reaction dynamic process of the Al-CrO3-NaF-Al2O3-N2-O2 new material system by the combustion synthesis method was discussed based on the observation results by SEM, EDS, and XRD in combination with the combustion front quenching method （CFQM） and the relation curves between reaction free enthalpies and the corresponding temperatures. The combustion synthesis mechanism and the formation reasons of the phase in the combustion product were analyzed.

Piezoelectric and dielectric properties of Cr-doped PSN-PZN-PZT qua-ternary piezoelectric ceramics

PSN-PZN-PZT + x wt. %Cr2O3, X = 0.0-0-9, were prepared by conventional mixed oxide techniques at sintering temperatures of 1220 degrees C-1300 degrees C for 2 h. The effect of sintering temperature on the microstructure and the piezoelectric properties was investigated by XRD, SEM, and other conventional measurement. The result indicated that with temperature increasing, the valence of Cr ion from Cr5+ or Cr6+ changes into C3+, and the piezoelectric properties turn hard. With increasing Cr2O3 content, the amount of rhombohedral phases increases and the morphotropic boundary phase is correspondingly shifts to rhombohedral phase. A uniform microstructure and excellent comprehensive properties were obtained at 1240 degrees C as the amount of Cr2O3 is 0.5 wt.%.

Supernova β^- decay of nuclides ^(53)Fe,^(54)Fe,^(55)Fe and ^(56)Fe in strongly screened plasma

Electron screening has strong effects on electron energy and threshold energy of the beta decay reaction.In this paper,we study β~-decay rates of some iron isotopes.The beta decay rates increase by about two orders of magnitude due to electron screening.Strongly screened beta decay rates due to Q-value correction are more than one order of magnitude higher than those without Q-value correction.

Beta decay of nuclides ^(56)Fe,^(62)Ni,^(64)Ni and ^(68)Ni in the crust of magnetars

By introducing the Dirac δ-function and Pauli exclusion principle in the presence of superstrong magnetic fields （SMFs）, we investigate the influence of SMFs on beta decay and the change rates of electron fraction （CREF） of nuclides 56Fe, 62Ni, 64Ni and 6SNi in magnetars, which are powered by magnetic field energy. We find that the magnetic fields have a great influence on the beta decay rates, and the beta decay rates can decrease by more than six orders of magnitude in the presence of SMFs. The CREF also decreases by more than seven orders of magnitude in the presence of SMFs.

Strong screening effects on resonant nuclear reaction ^(23)Mg(p,γ) ^(24)Al in the surface of magnetars

Based on the theory of relativistic superstrong magnetic fields （SMFs）, by using the method of Thomas-Fermi-Dirac approximations, we investigate the problem of strong electron screening （SES） in SMFs and the influence of SES on the nuclear reaction of 23Mg （p, Y）24A1. Our calculations show that the nuclear reaction will be markedly effected by the SES in SMFs in the surface of magnetars. Our calculated screening rates can increase two orders of magnitude due to SES in SMFs.

Opinion: Chemical--Mesoscopics..for the Mesoparticles Reactivity Explanation

The estimation of chemical particles reactivity and the determination of chemical reactions direction are the actual theme in new scientific trend-Chemical Mesoscopics.Paper includes the proposal about the using the theory of free energy linear dependence from physical organic chemistry and their applications for prognosis of reactions flowing.The semi-empiric constants is given according to mesoscopic physics definitions as well as the transformed Kolmogorov-Avrami equation is discussed.It is the development of Chemical Mesoscopics for organic reactivity estimation including nanostructures reactivity.

Ergodicity of Reversible Reaction Diffusion Processes with General Reaction Rates

In this paper,a class of reaction diffusion processes with general reaction rates is studied.A necessary and sufficient condition for the reversibility of this calss of reaction diffusion processes is given,and then the ergodicity of these processes is proved.

Reaction ergodography for the 1,2-H shift and inversion processes of amino-carbene

The ab initio calculations have been performed on the reaction paths of 1,2-H shift and inversion processes of amino-carbene molecule by the Intrinsic Reaction Coordinate(IRC)method. We have determined the equilibrium geometries and energies of the reactant,transition state and product,and obtained the activation energies,reaction heats,frequency factors and the activation entropies of these two reaction processes.The vibrational correlation from reactant to transition state indicated that the IRCs of 1,2-H shift and inversion processes were associated with the deformation modes of 1540 and 1208 cm^(-1),respectively.The vibrational coupling between normal coordinates in the inversion process would be helpful for selecting the inversion reaction channel.

Storage-reduction strategy for NO_(x) reduction from gas turbine exhaust with W-Ti-CeO_(x) catalyst in natural gas power plants

Traditional vanadium-based selective catalytic reduction(SCR)deNO_(x) catalyst can hardly adapt to the gas conditions(much high NO_(2)/NO_(x) ratio at lower temperature)of the start-up and low loading periods for a gas turbine.Therefore,a W-Ti-CeO_(x) catalyst with NO_(x) storage and reduction(NSR)function was developed in this work for gas turbine exhaust NO_(x) elimination.The experimental results reveal that W-Ti-CeO_(x) catalyst exhibits high NO_(2) adsorption capacity at relatively low temperature while that is quite low for V-W/TiO_(2).The abundant surface Ce^(3+) species can be mainly responsible for its high adsorption ability owing to the reaction between NO_(2) and Ce^(3+) to form nitrate/nitrite species and NO.Meanwhile,the adsorption capacity of W-Ti-CeO_(x) can easily regenerate at medium-high temperature and NH_(3)-SCR reaction.Furthermore,W-Ti-CeO_(x) also shows good NH_(3)-SCR activity,which can fulfill the deNO_(x) process at high temperature.The addition of W and Ti into ceria can enhance the surface acidity and redox ability,thereby increasing the SCR activity.This work proposes a novel storage-reduction strategy for NO_(x) elimination throughout the operation of gas turbines.

Strongly screening electron capture for nuclides ^(52,53,59,60)Fe by the Shell-Model Monte Carlo method in pre-supernovae

The death of massive stars due to supernova explosions is a key ingredient in stellar evolution and stellar population synthesis. Electron capture （EC） plays a vital role in supernova explosions. Using the Shell-Model Monte Carlo method, based on the nuclear random phase approximation and linear response theory model for electrons, we study the strong screening EC rates of 52,53,59,60Fe in pre-supernovae. The results show that the screening rates can decrease by about 18.66%. Our results may become late-type stars, supernova explosion mechanisms and a good foundation for future investigation of the evolution of numerical simulations.