Reactions of aryl 1-(2,4-dinitronaphthyl) ethers with piperidine in dimethyl sulfoxide at 25oC resulted in substitution of the aryloxy group at the ipso carbon atom. The reaction was measured spectrophotochemically and the kinetic studies suggested that the titled reaction is accurately third order. The mechanism is began by fast nucleophilic attack of piperidine on C1 to form zwitterion intermediate

The results of density functional theory calculations at the APFD/SDD level are detailed herein in order to study the main steps in the α,β-dehydrogenation of aldehydes and cyclic ketones in the presence of an allylpalladium complex catalyst. The mechanism is believed to proceed via an allylpalladium enolate complex (A) in equilibrium with the carbon-bonded complex (B), followed by β-hydride elimination

The co-combustion characteristics of Fujian anthracite with two biomasses (i.e. Cunninghamia lanceolata) and Mycorrhizal plants in different proportions were investigated using thermogravimetric analysis. The result showed that first, the co-combustion processes of Fujian anthracite with the two biomasses (Cunninghamia lanceolata and Mycorrhizal plants) proceeded in three stages, separation and combustion

This work presents a comprehensive study on the effects of pyrolysis parameters (pyrolysis temperature, residence time, and heating rate) on the distribution of pyrolysis products of Miscanthus. Py-GC/MS (Pyrolysis-gas chromatography/mass) was conducted to identify building blocks of value-added chemical from Miscanthus. The results showed that the main pyrolysis products of Miscanthus were ketone

The reaction kinetics among isoquinoline, dimethyl acetylenedicarboxylate, and indole (as NH-acid) were investigated using ultraviolet (UV) spectrophotometry. The reaction rate equation was obtained, the dependence of the reaction rate on different reactants was determined, and the overall rate constant (kov) was calculated. By studying the effects of solvent, temperature, and concentration on the

Accurate thermal decomposition mechanism and kinetic parameters are helpful to analyze the combustion process of flexible polyurethane foam. The thermal decomposition process of flexible polyurethane foam products (amine derivatives) was ignored in the past. Three thermal decomposition mechanisms of flexible polyurethane foam were proposed according to the thermogravimetry experiment of flexible polyurethane

The reaction mechanism between silacyclopropenylidene and three-membered heterocyclic compounds (azirane and oxirane) has been systematically investigated at the B3LYP/6-311+G* level of theory in order to better understand the reactivity of unsaturated cyclic silylene. Geometry optimizations and vibrational analyses have been conducted for the stationary points on the potential energy surface of the

The production of hydrogen by steam reforming of ethanol was carried out on SBA-15-supported nano NiO catalyst synthesized by the equivalent-volume impregnation method with two different Ni sources (nickel nitrate and nickel sulfamate). The catalyst was characterized by N2 adsorption–desorption, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy to examine the

Although natural gas hydrates and hydrate exploration have been extensively studied for decades, the reaction kinetics and nucleation mechanism of hydrate formation is not fully understood. In its early stage, gas hydrate formation can be assumed to be an autocatalytic kinetic reaction with nucleation and initial growth. In this work, a reaction kinetics model has been established to form structure

Theoretical investigations have been performed on the kinetics of bimolecular hydrogen-abstraction reactions of 1,3,5-trioxane and 1,4-dioxane cyclic ethers with OH radicals. Hydrogen abstraction from both axial and equatorial positions of 1,3,5-trioxane and 1,4-dioxane was considered. Optimization of the structures, and the calculation of energies, vibrational frequencies and moments of inertia for

We have examined here the possibility of functionalization of the B12N12 cluster by methyl azide by means of a [2 + 3] cycloaddition reaction in analogy with the spontaneous functionalization of C20 fullerene using the same reaction. To achieve more reliable data, all possible interactions at different positions and orientations were considered by reaction channel study and potential energy surface

Equilibrium constants and reaction rate constants for the esterification of secondary alkan-2-ols with acetic acid were measured at 60°C in 1,4-dioxane. Taft coefficients, as single parameter (without inductive effects), and two-parameter correlation (including inductive and steric effects), of the measurements were used for the prediction of esterification rate constants for secondary alkan-2-ols

A series of magnetically separable catalysts based on Ru–Ni bimetallic compounds supported on Fe3O4 nanoparticles was prepared by the co-precipitation method. These catalysts were evaluated for diformyltricyclodecanes hydrogenation reactions, achieving 97% tricyclodecanedimethylol selectivity at 98% diformyltricyclodecanes conversion under mild conditions. The catalyst could be easily recovered by

La–Ni–S2O82–/ZrO2–Al2O3 catalysts were successfully prepared by two different methods of sulfate impregnation, and the physico-chemical properties of the catalysts were characterized by X-ray diffraction, Brunauer–Emmett–Teller analysis, Fourier transform infrared spectroscopy, pyridine adsorption–infrared spectroscopy, and X-ray photoelectron spectroscopy techniques. Catalytic activities were evaluated

A series of APTMS ((3-aminopropyl)trimethoxysilane)-modified silicate MCM-41 adsorbents (x-APTMS/MCM-41, x is the volume of APTMS per 1 g of silicate MCM-41) with different APTMS contents was prepared, and the effects of APTMS content on the desulfurization performance of the APTMS/MCM-41 adsorbents were studied in a fixed adsorption bed using H2S and N2 mixture as a model gas. The as-prepared adsorbents

The reaction kinetics of carbon reduction of silica were investigated using thermodynamic concepts and by fitting to relevant models the experimental data obtained for this reduction using a thermogravimetric unit in the temperature range of 1566 to 1933 K. The results show that the only way to produce SiC in this reduction is the reaction of Si, SiO, or SiO2 at the surface or by diffusion of SiO inside

Platinum-carbonaceous catalysts were prepared by the wet impregnation method and tested for catalytic oxidation of toluene as a volatile organic compound. The textural properties of the constructed catalysts were considered by X-ray diffraction, X-ray fluorescence, inductively coupled plasma – optical emission spectroscopy, Fourier transform infrared, scanning electron microscope and N2 adsorption–desorption

The ammonium uranyl carbonate, (NH4)4UO2(CO3)3, is an important material used in UO2 and U3O8 ceramics production for the nuclear fuel fabrication. Thermal study and kinetic analysis of ammonium uranyl carbonate conversion under isothermal conditions has been studied in air atmosphere to obtain the tri-uranium octoxide (U3O8), using muffle furnace equipment, UV–visible spectrophotometer, gas adsorption

Kinetic rate constants for the oxidation reaction of the hydroxyl radical with CH3SH, C2H5SH, n-C3H7SH, and iso-C3H7SH under inert (Ar) conditions over the temperature range 252–430 K have been studied theoretically using density functional theory along with various exchange–correlation functionals as well as the benchmark CBS-QB3 quantum chemical approach. Bimolecular rate constants were estimated

The mechanistic nature of a [3+2] cycloaddition reaction involving zwitterionic species has been investigated, and the changes of electron density related to the O–C and C–C bond formation along the intrinsic reaction coordinate have been characterized. This polar [3+2] cycloaddition reaction, which takes place through a non-concerted two-stage one-step mechanism, proceeds with a moderate Gibbs free

A large number of heterogeneous catalysts were tested in the aldol condensation of heptanal with cyclopentanone. There are many possible products from this aldol condensation, among which the most desired is 2-heptylidenecyclopentanone. As heterogeneous catalysts, the following were tested: caesium modified zeolites, functionalized MCM-41, and single (MgO, CaO, ZnO) and double (Mo–Si, Mg–Al, Zn–Al)

A novel method for preparing Ni2P/Al2O3(L) catalysts in an N2 atmosphere by decomposition of hypophosphites was proposed, and Ni2P/Al2O3(T) catalyst was synthesized by the temperature programmed reduction method in a H2 atmosphere for comparison. These prepared catalysts were washed with deionized water to remove impurities. The X-ray diffraction, N2-adsorption specific surface area measurements, CO

In this work, we focus our attention on chemical reactions confined within carbon nanotubes. As a result of the confinement within carbon nanotubes, novel physical and chemical properties are found for the confined materials. We consider the feasibility of proton transfer inside carbon nanotubes. To do that, we have chosen formamide as the simplest real model for exhibiting the tautomerization in DNA

A series of Ni–Fe/MCM-41 bimetallic catalysts and also Ni/MCM-41 and Fe/MCM-41 catalysts were prepared by the incipient-wetness impregnation method and tested for their activity for CO methanation in a continuous-flow microreactor. The results showed that the catalytic activities of the Ni–Fe/MCM-41 bimetallic catalysts were much higher than those of the Ni/MCM-41 and Fe/MCM-41 catalysts at low temperatures

New 1H and 13C NMR 400 MHZ spectra of the 2-Nb cation under stable ion conditions, for example, in SbF5/SO2F2/SO2ClF, −80 oC, show besides the usual 1H NMR resonances at δ 4.93, 2.82, 1.85, the never before seen singlet, δ 9.63, and doublet, δ 2.97 (J2,6 = 16.6 Hz), ratio 1.00 : 1.07, proposed to be due to resonance-stabilized bridgehead 1-Nb cationic enantiomers in equilibrium with 2-Nb cation. The

Using [H2O2] in the molar range, the reaction with Fe2+ has two phases: in the first rapid phase, only a small fraction of the total O2 is evolved; the bulk of the gas is formed in a slow second phase. In interpretations based on the free radical model of Barb et al., the first phase has been identified with the ‘Fenton reaction’ (reaction of Fe2+with H2O2), while the second with catalytic decomposition

The effects of metallic cobalt crystal phase on catalytic activity of cobalt catalysts in the Fischer–Tropsch synthesis were investigated in a continuous spinning basket reactor. The cobalt catalysts were prepared by impregnation of the cobalt active phase in a microemulsion system on multiwall carbon nanotube supports. A series of cobalt catalysts with different Co particle sizes was prepared by variation

A nickel phosphide hydrodeoxygenation catalyst (Ni2P-O/MCM-41) was prepared using a new synthetic method. The as-prepared catalyst was evaluated in the hydrodeoxygenation of benzofuran, and the effects of reaction temperature, pressure, and the H2/liquid ratio were investigated. A pseudo first-order model was employed to describe the reaction kinetics of benzofuran hydrodeoxygenation over the Ni2P-O/MCM-41

In this article, hybrid functional B3LYP method is used to construct the reactant structure of energetic components in propellant at the bhandhlyp/6-31g(d) level, and to calculate the closed-shell layer of the system. At the bhandhlyp/6-31g(d) level, the energy difference (activation energy) between the transition state and the reactant was calculated and the reaction mechanism between energetic components

The sorption kinetics and thermodynamic parameters of phosphate removal from aqueous solution using quaternary ammonium–modified bottle gourd biomass as a sorbent were studied in a batch reactor. The cationic sorbent, containing trimethylammonium and hydroxypropyl groups, was obtained through the chemical reactions of the lignocellulosic Lagenaria vulgaris shell with (3-chloro-2-hydroxypropyl)trimethylammonium

Bi24Br10+xAg x O31 nanosheets were prepared by a facile single-step co-precipitation method in the presence of 1-butyl-3-methylimidazolium bromide ionic liquid as the bromide source and template agent. The products were well characterized by X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, diffuse reflectance spectroscopy, nitrogen adsorption–desorption isotherms

The formation kinetics of the complex, [Ru(CN)5INH]3−, formed through the ligand substitution reaction between isoniazid (INH) and aquapentacyanoruthenate(II) ([Ru(CN)5H2O]3−), have been investigated, under pseudo first-order conditions, as a function of concentrations of [INH] and [Ru(CN)5H2O]3−, ionic strength and temperature at pH = 4.0 ± 0.02 in 0.2 M NaClO4 spectrophotometrically at 502 nm (λmax

The interaction of biotin and streptavidin in the presence and absence of a carbon nanotube was studied by molecular dynamics simulation. With respect to the Arrhenius dependence of the rate constants with temperature, those of streptavidin–biotin complex formation ( k 1 ) and streptavidin–biotin complex dissociation ( k − 1 ) were calculated from molecular dynamics simulation trajectories. Nanotube

The density functional theory method is employed to systematically explore the mechanism of syngas methanation on the Ni4/MCM-41 catalyst surface. The calculation results show that the optimal pathway of CH4 formation is CO + H → CHO + H → CH2O + H → CH3O → CH3 + H → CH4 with the rate-determining step of CH3O direct dissociation. Because the activation energy for the direct dissociation of CH3O species

The kinetics of the aquation reaction of the [VO(ida)(bipy)]·2H2O (VO(ida)(bipy)) complex (where ida = iminodiacetate anion and bipy = 2,2’-bipyridine) promoted by [Fe(H2O)6]3+ ions were investigated in aqueous solutions. Spectrophotometric studies were carried out at different temperatures in the range of 293.15–313.15 K. The concentration of the [Fe(H2O)6]3+ (Fe3+) ions was kept within the range

Changing the mechanism of the widely used 1,3-dipolar cycloaddition reaction from its usual asynchronous one-step pattern to the rarely observed stepwise form leads to the emergence of intermediates, side products, and other impurities. Thus, it is crucial to determine the nature of the mechanism of the 1,3-dipolar cycloaddition reaction between a special 1,3-dipole and a specified dipolarophile (by

X2Si=Sn: (X = H, Me, F, Cl, Br, Ph, Ar, etc.) are a new chemical species. The cycloaddition reactions of X2Si=Sn: are a new field of stannylene chemistry. The mechanism of the cycloaddition reaction between singlet state Me2Si=Sn: and ethene has been investigated for the first time here using second-order Møller-Plesset perturbation theory together with the 6-311++G** basis set for C, H and Si atoms

CuO- and Ag2O-decorated g-C3N4 photocatalysts were prepared by appropriate chemical modification of carbon nitride nanosheets produced from programmed pyrolysis of urea. After comprehensive characterization by powder X-ray diffraction, diffuse reflectance spectroscopy, Fourier transform–infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller analysis methods, their photocatalytic

Glyoxal can be important in atmospheric chemistry in terms of its ability to convert to secondary organic aerosols. In this study, the glyoxal-breaking reaction by two atmospheric active radicals, NO2 and NH2, has been investigated at the B3LYP and M06-2X levels in connection with 6-311++G(d,p) basis set. The formation of the most stable adducts from glyoxal with NO2/NH2 radical requires two hydrogen

The tautomeric equilibrium of benzimidazolone and benzimidazolthione have been studied by the density functional theory method using the CAM-B3LYP functional together with the 6-311G(d,p) basis set. Two separate mechanisms have been investigated: a direct intramolecular transfer using the polarizable continuum model and an indirect proton transfer assisted by a molecule of solvent (C6H12, H2O, CH3OH

Density functional theory calculations were employed to investigate the electrochemical oxygen reduction reaction on the (111) and (100) surfaces of cobalt(II) oxide. Different mechanisms were applied to evaluate the oxygen reduction reaction performance of cobalt(II) oxide structures in terms of the Gibbs free energy and density of states. A variety of intermediate structures based on associative

Non-isothermal pyrolysis and gasification of Enteromorpha prolifera (also known as Ulva prolifera) under a CO2 atmosphere were investigated by thermogravimetry analysis. The gaseous products were measured online with Fourier transform infrared spectroscopy coupled with thermogravimetry. The kinetic parameters of pyrolysis and gasification reactions were obtained using the Coats–Redfern method. The

Substitution reactions of square-pyramidal [ZnCl2(terpy)] complex (terpy = 2,2′:6′,2″-terpyridine) with biologically relevant nucleophiles such as imidazole, glutathione, 1,2,4-triazole, and pyrazine were investigated at pH 7.0 as a function of nucleophile concentration. The reactions were followed under pseudo first-order conditions by UV-Vis spectrophotometry. The substitution reactions comprised

Kinetic rate constants for the oxidation reactions of OH radicals with CH3SH (1), C2H5SH (2), n-C3H7SH (3) and iso-C3H7SH (4) under inert conditions (Ar) over the temperature range 252−430 K have been studied using the CBS-QB3 composite method. Kinetic rate constants under atmospheric pressure and in the fall-off regime have been estimated using transition state theory (TST) and statistical Rice–R

Using Fe6(OH)18(H2O)6 as a ring cluster model for superparamagnetic iron oxide nanoparticles, noncovalent configurations and three mechanisms of covalent functionalization of superparamagnetic iron oxide nanoparticles with cyclophosphamide an anticancer drug were studied. Quantum molecular descriptors, solvation, and binding energies of noncovalent interactions were investigated the in gas and solution

In this work, the mechanism of the palladium-catalysed acetoxylation of benzene C-H has been studied theoretically in detail. Based on experimental studies, a four-step mechanism for this reaction had been proposed, that is, C−H activation of benzene is the rate-determining step which forms an intermediate (k1 pathway) which is subsequently oxidized to produce a high-valent Pd intermediate (k2 pathway)

This study employed Nb2O5.nH2O for the dehydration of butane-2,3-diol, which could be derived from biomass or waste gas using a fermentation process. The experiments were conducted at a temperature ranging from 220 °C to 260 °C and a weight hourly space velocity of 0.01–0.05 min−1. There are three main products that include methyl ethyl ketone, isobutyraldehyde, and butadiene. The yield of products

Neodymium (Nd)- or yttrium (Y)- modified bulk Ni2P catalysts (Nd-Ni2P or Y-Ni2P) have been successfully prepared and their catalytic performance in benzofuran hydrodeoxygenation have been investigated. The as-prepared catalysts were characterised by X-ray diffraction, N2 adsorption–desorption, CO uptake and X-ray photoelectron spectroscopy. The addition of Nd or Y, especially Nd, can increase the surface

A series of ceria promoted Ni2P catalysts were prepared and evaluated in dibenzothiophene hydrodesulfurization steam. These catalysts were characterized by X-ray diffraction, N2 adsorption–desorption, CO chemisorptions, and X-ray photoelectron spectroscopy. The results showed that the addition of ceria into the bulk Ni2P catalyst was conducive to the formation of the Ni2P phase and contributed to a

By performing density functional theory calculations, the adsorption configurations of formic acid and possible reaction pathway for HCOOH oxidation on PtPd(111) surface are located. Results show that CO2 is preferentially formed as the main product of the catalytic oxidation of formic acid. The formation of CO on the pure Pd surface could not possibly occur during formic acid decomposition on the

A series of Ti-incorporated bulk Ni2P catalysts was prepared by means of temperature-programmed reduction, and the role of metallic Ti on the structure and catalytic activity of the Ni2P catalysts was studied. For this purpose, bulk Ni2P catalysts with metal Ti contents of 0.005 wt%, 0.01 wt%, and 0.02 wt% were synthesized. X-ray diffraction, CO uptake, Brunauer–Emmett–Teller measurements, and X-ray

By employing a combined approach of the unity bond index–quadratic exponential potential method and density functional theory within the generalized gradient approximation, we have studied the interaction of intermediates in the ethanol dehydrogenation process to ethyl acetate on Cu, Ag, Ni, Pd, Pt, Co, Au and Ir(111) transition metal surfaces. Binding energies and geometries were optimized for the

The kinetics of carbon monoxide methanation over Ni-Mo-SiO2 catalyst were studied. The model was developed based on catalyst tests carried out in a fixed-bed reactor at a reaction temperature varied from 300 °C to 450 °C under a pressure from 0.1 to 1.5 MPa with a weight hourly space velocity of 60,000 mL h−1 g−1. An orthogonal design method was adopted to select test points with temperature, pressure

Kinetic and mechanistic studies of the oxidation of mandelic acid and nine monosubstituted mandelic acids by benzimidazolium dichromate (BIDC) in dimethyl sulfoxide are discussed with an emphasis on correlation of structure and reactivity. The reactions were of first order with respect to BIDC. However, Michaelis-Menten type kinetics were observed with respect to hydroxy acids. The reactions are catalysed

The activities of cobalt catalysts prepared by the microemulsion impregnation method on carbon nanotubes (CNTs) and functionalised carbon nanotubes (FCNTs) supports were evaluated in the Fischer–Tropsch synthesis (FTS). The catalysts were characterised by transmission electron microscopy, X-ray diffraction and Brunauer–Emmett–Teller surface area methods. The results show that the cobalt particles in

Pyrolysis of Tetra Pak waste under CO2 was investigated using a thermogravimetric/differential thermal analyser coupled with a Fourier transform infrared spectrometer. Experimental results showed that cellulose was decomposed between 270 and 390 °C, leading to the formation of aldehydes, ketones, carboxylic acids and levoglucosan. Thermal cracking of polyethylene occurred between 440 and 530 °C and

The synthesis and interactions of the cis-diaqua-chloro-tris(dimethyl sulfoxide)ruthenium(II) complex with selected sulfur-containing ligands such as 2-thiouracil, glutathione and L-cysteine have been studied by UV-Vis spectrophotometry in aqueous medium at pH 4.5. From experimental data it is clear that all three reactions proceed via two steps: the first one being a rate-limiting ligand-dependent

First, the effects of ultrasound-related variables on the crystallinity and particle size of synthesised SAPO-34 catalysts were modelled using a genetic programming (GP) method. The results confirm that GP has good predictive power. Secondly, optimisation of the ultrasound parameters was considered using a genetic algorithm (GA) to obtain SAPO-34 catalysts with high crystallinity and minimum particle

The adsorption of NH3 and NO on the β-MnO2 (1 1 0) surface has been investigated by density functional theory using periodic models. The energetically favourable sites of adsorption of the gases on the β-MnO2 surface are 4-fold coordinate Mn (Mn4-top) and 5-fold coordinate Mn (Mn5-top). The relative adsorption energies (Eads) of these gases on the Mn4-top site and Mn5-top site are in the orders NH3

The mole-ratio method was used to determine the metal–ligand stoichiometry between [ZnCl2(en)] and [ZnCl2(terpy)] (where en = 1,2-diaminoethane or ethylenediamine and terpy = 2,2′:6′,2″-terpyridine) and imidazole at pH 7.2 in the presence of different chloride concentrations. The results indicated step-wise formation of 1:1 and 1:2 complexes in the presence of 0.010 M NaCl and 1:1 complexes in the