Presence Of Nickel Catalyst Research Articles

Nickel‐Catalyzed Reductive Amidation of Aryl Sulfonium Salts with Isocyanates for Amide Synthesis via C−S Bond Activation

AbstractA nickel‐catalyzed reductive amidation of aryl sulfonium salts with isocyanates for amide synthesis via C−S bond cleavage was developed. The reactions proceeded smoothly at ambient temperature in the presence of nickel catalyst and manganese metal in DMF to give a variety of amides in moderate to good yields with wide functional group tolerance.

Radiation-induced dry reforming: A negative emission process

The reaction between the most abundant greenhouse gases (GHG) to produce hydrogen might represent the most powerful and effective decarbonizing opportunity, if a low-carbon energy source is used to drive it. This is the case of methane (CH4) dry reforming (MDR) where its reaction with carbon dioxide (CO2) produces synthesis gas (syngas, a mixture of carbon monoxide and hydrogen). This study explores the feasibility of using ionizing radiation to induce the MDR reaction, at low temperatures and/or less energy demanding conditions. Additionally, the ionizing radiation is proposed to be supplied by nuclear power plants (NPPs), which are low-carbon reliable energy generation sources. Thus, the radiolysis of CO2, CH4 and their mixtures, under γ-irradiation was evaluated in the absence and presence of nickel catalysts. The radiation-induced MDR reaction and radiation-induced catalytic promotion were proven to take place at temperatures close to ambient though at low conversion, with yields below 1%. Since irradiation and heat can be provided by a nuclear power plant, this radiation-induced reaction establishes a connection between nuclear energy to renewable resources and enables a pathway for a decarbonized cleaner chemical industry, for producing green chemicals.

Aquathermolysis of Heavy Crude Oil: Comparison Study of the Performance of Ni(CH3COO)2 and Zn(CH3COO)2 Water-Soluble Catalysts

Aquathermolysis is one of the crucial processes being considered to successfully upgrade and irreversibly reduce the high viscosity of heavy crude oil during steam enhanced oil recovery technologies. The aquathermolysis of heavy oil can be promoted by transition metal-based catalysts. In this study, the catalytic performance of two water-soluble catalysts Ni(CH3COO)2 and Zn(CH3COO)2 on the aquathermolytic upgrading of heavy oil at 300 °C for 24 h was investigated in a high pressure–high temperature (HP-HT) batch reactor. The comparison study showed that nickel acetate is more effective than zinc acetate in terms of viscosity reduction at 20 °C (58% versus 48%). The viscosity alteration can be mainly explained by the changes in the group composition, where the content of resins and asphaltenes in the upgraded heavy crude oil sample in the presence of nickel catalyst was reduced by 44% and 13%, respectively. Moreover, the nickel acetate-assisted aquathermolysis of heavy oil contributed to the increase in the yield of gasoline and diesel oil fractions by 33% and 29%, respectively. The activity of the compared metal acetates in hydrogenation of the crude oil was judged by the results of the atomic H/C ratio. The atomic H/C ratio of crude oil upgraded in the presence of Ni(CH3COO)2 was significantly increased from 1.52 to 2.02. In addition, the catalyst contributed to the desulfurization of crude oil, reducing the content of sulfur in crude oil from 5.55 wt% to 4.51 wt% The destructive hydrogenation of resins and asphaltenes was supported by the results of gas chromatography-mass spectroscopy (GC-MS) and Fourier-transform infrared (FT-IR) spectroscopy analysis methods. The obtained experimental results showed that using water-soluble catalysts is effective in promoting the aquathermolytic reactions of heavy oil and has a great potential for industrial-scale applications.

Nickel-Catalyzed Direct Cross-Coupling of Aryl Fluorosulfates with Aryl Bromides

A one-pot, direct cross-coupling of aryl fluorosulfate with aryl bromide, which is step-economical and avoids the use of a preprepared/commercial organometallic reagent, could be accomplished by performing the reaction in THF at room temperature in the presence of nickel catalyst, magnesium turnings, and lithium chloride, giving rise to the corresponding biaryls in moderate to good yields with reasonable functional group compatibility.

Theoretical Study on the Formation of 2-Pyrone Derivatives from the Reaction of Alkynes with Carbon Dioxide in the Presence of Nickel Catalyst

The formation of 2-pyrone derivatives by the reaction of CO2 with a model internal alkyne, 2-butyne, in the presence of (cod)2Ni and a bisphosphine ligand (dppb), was studied using the M06/6-311G(d,p) density functional theory method, which revealed that the reaction takes place in three stages. The first stage is the formation of the 2-butyne complex intermediate (dppb)Ni(η2-MeC≡CMe). There are several pathways for the formation of 2-pyrone complexes from it, and the more favorable two pathways were found among them. In the second stage, the coupling of (dppb)Ni(η2-MeC≡CMe) with 2-butyne or CO2 produces nickelacyclopentadiene or oxanickelacyclopentenone with the Ni–O bond, respectively. In the third stage, the reaction of CO2 with nickelacyclopentadiene or that of 2-butyne with oxanickelacyclopentenone produces 2-pyrone Ni complexes. The rate-limiting step is the second, in which nickelacyclopentadiene or oxanickelacyclopentenone is formed. The formation of oxanickelacyclopentenone with the Ni–O bond is kinetically more favorable, while the formation of nickelacyclopentadiene is thermodynamically more favorable. Thus, depending on the experimental conditions, the two pathways are in competition. This supports the mechanisms suggested by Inoue et al. and Hoberg et al., and we discuss the factors that make these mechanisms more favorable.

Novel Cholinesterase Inhibitors: Synthesis, in silico and in vitro Studies

The synthesis of new functionalized linear diaza and triaza phenothiazine and phenoxazines and their in silico and in vitro anti-Alzheimer activity is reported. Fifteen new amide derivatives (8-11 & 13-24) were synthesized by the reactions of phenothiazines/phenoxazine (6 or 12) and various aliphatic and aromatic primary amides (7) in the presence of nickel catalyst and anhydrous potassium carbonate under nitrogen atmosphere. The FTIR, 1H NMR, 13C NMR and HR-MS spectra of the synthesized compounds were in agreement with the assigned structures. All the 15 new derivatives were screened for their in silico and in vitro anti-Alzheimer’s activity using the inhibition of acetylcholinesterase and butyrylcholinesterase. The results of the in silico experiment showed that most of the synthesized derivatives had good binding energies, binding interaction and bond distances. The most active derivatives in the in silico studies was compounds 18 (-12.5 and -11.5 kcal/mol) against acetylcholinesterase and butyrylcholinesterase, respectively. In addition, compound 18 had the best in vitro inhibitory activity against acetylcholinesterase and butyrylcholinesterase (99.37% and 82.35%). The results of in silico experiment were greatly in agreement with the results of in vitro studies. The structure-activity relationship studies revealed that the phenothiazine derivatives had better in silico and in vitro activities. Furthermore, 2-substitutted phenothiazines had better activity than the unsubstituted phenothiazines. The synthesized compounds showed promising in silico and in vitro activities against acetylcholinesterase and butyrylcholinesterase and as such could be further developed for the treatment of Alzheimer’s disease.

The effect of clay minerals on conversion of Yarega heavy oil during catalytic aquathermolysis process

In this study we present the results of physical stimulation of in-situ aquathermolysis process carried out on heavy crude oil sample from Yarega (Russia) oil field in the presence of nickel/iron tallates and clay minerals. The experimental results revealed that clay minerals as the co-catalyst show the best performance at 300 °C in case of nickel tallates, where the viscosity of aquathermolysis products reduces by 4 times in contrast to the initial crude oil. Moreover, the content of saturated fraction isolated from the catalytic aquathermolysis products increased from 36.8 to 50.2 in contrast to the saturated fraction of initial crude oil, while the amount of resins decreased by two times after hydrothermal treatment in the presence of nickel catalyst and clay minerals. Thus, the obtained results justify the involvement of clay minerals to the aquathermolysis process and demonstrate catalytic performance in terms of enhancing group composition and viscosity reduction. Keywords: heavy oil; upgrading; catalysts; aquathermolysis; clay minerals; transition metals; SARA; rheology.

Supercritical Water Gasification as Treatment for High Lipid Content Biomass in the Presence of Nickel Catalyst

Supercritical Water Gasification as Treatment for High Lipid Content Biomass in the Presence of Nickel Catalyst

Nickel‐Catalyzed Deaminative Cross‐Coupling of Disulfides with Katritzky Pryidium Salts to Construct Sulfides

AbstractThe synthesis of thioether or selenoether through the cross‐coupling of C−S or C−Se bond is a high attractive research area due to the prevalence of thioether or selenoether in pharmaceutically active compounds, bioactive natural compounds, agrochemicals, and functional materials. Herein, a novel and general method has been developed for the construction of C−S or C−Se bonds using Katritzky pyridinium salts with disulfides or diselenides in the presence of nickel catalyst. This procedure exhibits remarkable functional group tolerance. Under mild reaction condition, a variety of thioethers and selenoethers is successfully and efficiently obtained through deaminative cross‐coupling.

Boron doped graphene synthesis using pulsed laser deposition and its electrochemical characterization

During the design of graphene (G), their electronic, chemical and electrochemical properties among others can be tuned by incorporating heteroatoms in the honeycomb structure. In this study, we investigated boron doped graphene (BG) synthesis and the effect of boron content on the electrochemical property of graphene. To this end, BG was synthesized using pulsed laser deposition (PLD) with carbon and boron as solid sources, followed by rapid thermal annealing in the presence of nickel catalyst. Raman spectroscopy revealed that the BG films consisted of few-layer graphene and boron doping increased the defects level in the films. X-ray photoelectron spectroscopy confirmed the successful boron doping into the graphene with the control of boron content. Electrochemical characterization demonstrated that BG electrodes exhibit higher reversibility and electron transfer constant than the G electrode. All these results prove that PLD method is a viable alternative way to produce BG films with excellent electrochemical properties.

Enhancing field electron emission behavior and mechanical properties of hydrogenated amorphous carbon films by incorporating vertically aligned carbon nanowires via facile reactive magnetron sputtering

A reactive magnetron sputtering deposition facility was performed to fabricate well-aligned carbon nanowires (denoted as CNWs) in hydrogenated amorphous carbon (denoted as a-C:H) film via a one-step self-assembly route in the presence of nickel catalyst. The CNWs arrays with different diameters and vertical alignment on substrate surfaces were incorporated in the a-C:H films under different deposition time. The microstructure of the as-fabricated CNWs/a-C:H composite films was analyzed by field emission scanning electron microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Moreover, the field electron emission behavior of CNWs/a-C:H composite films in vacuum was tested with a parallel-plate-electrode system; and their nano-hardness and adhesion to substrate were measured by nano-indentation and nano-scratching tests. Results indicate that the CNWs/a-C:H composite films exhibit greatly increased electric conductivity and nano-hardness as well as desired flexibility. Particularly, the CNWs/a-C:H composite film obtained at a deposition time of 10 min has the optimal comprehensive properties, showing promising potential in the large-area preparation of flexible electronic devices.

Asymmetric Stepwise Reductive Amination of Sulfonamides, Sulfamates, and a Phosphinamide by Nickel Catalysis.

Asymmetric reductive amination of poorly nucleophilic sulfonamides was realized in the presence of nickel catalysts and titanium alkoxide. A wide range of ketones, including enolizable ketones and some biaryl ones, were converted into sulfonamides in excellent enantiomeric excess. The cyclization of sulfamates and intermolecular reductive amination of a diarylphosphinamide were also successful. Formic acid was used as a safe and economic surrogate of high-pressure hydrogen gas.

Asymmetric Stepwise Reductive Amination of Sulfonamides, Sulfamates, and a Phosphinamide by Nickel Catalysis

AbstractAsymmetric reductive amination of poorly nucleophilic sulfonamides was realized in the presence of nickel catalysts and titanium alkoxide. A wide range of ketones, including enolizable ketones and some biaryl ones, were converted into sulfonamides in excellent enantiomeric excess. The cyclization of sulfamates and intermolecular reductive amination of a diarylphosphinamide were also successful. Formic acid was used as a safe and economic surrogate of high‐pressure hydrogen gas.

Production of carbon nanotubes on bio-char at low temperature via microwave-assisted CVD using Ni catalyst

Microwave-assisted chemical vapor deposition (CVD) was employed for the synthesis of carbon nanotubes (CNTs) on pine nut shell (PNS) chars. The impact of reaction temperature, catalyst, carbon source, and the renewable carbon substrate on the synthesis of the CNTs were investigated. Microwave irradiation, the type of carbon source, and the presence of nickel catalyst were found to be the governing factors during the formation and growth of CNTs at low temperatures. 600 °C was found to be the optimum temperature for the formation of the CNTs. The high-resolution transmission electron microscope (HRTEM) results showed that the CNTs synthesized at 600 °C had a multiwall structure and a d-spacing of 0.34 nm. The diameter and length of CNTs were ~50 nm and 2600–3200 nm, respectively. Raman spectroscopy analysis revealed that a high degree of carbon order was achieved at 600 °C due to the formation of CNTs on the surface of bio-char. The formation and growth mechanisms of CNTs under microwave irradiation were proposed and discussed.

Influence of uniaxial pressing and nickel catalytic additive on activation of magnesium hydride thermal decomposition

Speed-up of thermal decomposition of magnesium hydride due to uniaxial pressing, including pressing in presence of nickel catalyst, was studied by barometry, SEM, DSC, XRD methods, and using mathematical modeling. Pressing even with no catalyst is shown to hasten the hydrogen desorption. The most probable reason for this is the formation of multiple defects in crystal lattice. They can serve as nucleation centers: metal nuclei significantly hasten hydrogen desorption. Besides, metal magnesium not converted to the hydride during the synthesis stage can possibly appear at surface. Adding nickel powder before pressing hastens dehydriding process even more. Comparing hydrogen evolution curves for samples with different amount of nickel allowed to propose the probable mechanism of hydrogen evolution. It is based on description of reactions of hydrogen desorption and hydride decomposition and of the metal-hydride phase morphology change due to these reactions. We develop a mathematical model in form of ordinary differential equations that fits the experimental data well. The model is based on conservation and symmetry assumptions. The fitting allowed to evaluate rate parameters of hydride phase decomposition.

Nickel-Catalyzed Decarbonylative Borylation and Silylation of Esters

The nickel-catalyzed direct borylation and silylation of phenolic esters has been established. The key to this highly efficient acyl C–O bond borylative and silylative cleavage depends on the appropriate choice of different ligands and additives in the presence of nickel catalyst. Both transformations exhibit good functional group compatibility and can serve as powerful synthetic tools for late-stage functionalization of complex compounds. The elucidation of key mechanistic features of this newly developed acyl C–O bond activation in esters was confirmed by two well-characterized organonickel(II) intermediates.

Nickel-Catalyzed Enantioselective Reductive Amination of Ketones with Both Arylamines and Benzhydrazide.

An asymmetric reductive amination of ketones using both arylamines and benzhydrazide in the presence of nickel catalysts was developed. A one-pot synthesis of tetrahydroquinoxalines was also developed starting directly from α-ketoaldehydes and 1,2-diaminobenzene. Formic acid was used as a safe and economic surrogate for high-pressure hydrogen gas. Strongly σ-donating bis(alkylphosphine)s are crucial ancillary ligands for both stereoselective hydride insertion and decarboxylation of the formate.

Nickel‐Catalyzed Enantioselective Reductive Amination of Ketones with Both Arylamines and Benzhydrazide

AbstractAn asymmetric reductive amination of ketones using both arylamines and benzhydrazide in the presence of nickel catalysts was developed. A one‐pot synthesis of tetrahydroquinoxalines was also developed starting directly from α‐ketoaldehydes and 1,2‐diaminobenzene. Formic acid was used as a safe and economic surrogate for high‐pressure hydrogen gas. Strongly σ‐donating bis(alkylphosphine)s are crucial ancillary ligands for both stereoselective hydride insertion and decarboxylation of the formate.

Consideration on Acid Accelerator Oriented to Reproduction of Sodium Borohydride from By-Product

The authors have proposed and made a hydrogen supply system for FCHEV. This system can generate large amount of hydrogen by hydrolysis of powdery sodium borohydride (NaBH4). In the proposed system, the hydrolysis reaction rate is low even under the presence of nickel catalyst when the temperature is low. As a solution of this problem, until now, an acid solution like as citric acid is added until its temperature reached near 50℃. However, in the case of using the citric acid, an impurity like citrate is produced. Thus, it is desired to generate hydrogen without using the citric acid when the temperature is low. Therefore, in this research, a boric acid (H3BO3) as a new acid accelerator was considered in order not to product the impurity. Through experiments, we confirmed that hydrogen could generate continuously and the solution temperature could increase until the target temperature with using the boric acid when the temperature was low.

Coupling of aromatic aldehydes with aryl halides in the presence of nickel catalysts with diazabutadiene ligands

Nickel catalysts with diazabutadiene ligands promote cross-coupling of benzaldehydes with aryl halides in the presence of zinc as reducing agent, which leads to the corresponding benzhydrols and benzophenones. The benzophenone percentage considerably increases when lithium chloride additive is used.