Formamide condensation with Ni can generate the N–C structure,widely recognized as an efficient catalyst for electrocatalytic CO_(2) reduction reaction(CO_(2)RR).To improve the utilization efficiency of Ni atoms,we i...Formamide condensation with Ni can generate the N–C structure,widely recognized as an efficient catalyst for electrocatalytic CO_(2) reduction reaction(CO_(2)RR).To improve the utilization efficiency of Ni atoms,we introduced metal oxides as substrates to modulate the growth of a formamide-Ni(FA-Ni)condensate.FA-Ni@TiO_(2) demonstrated 2.8 times higher partial CO current density and Ni turnover frequency than FA-Ni,which were also higher than those of other FA-Ni@metal oxides,including ZrO_(2),Al_(2)O_(3),Fe_(2)O_(3),and ZnO.The improved performance of CO_(2)RR can be attributed to the Ni content exposed on FA-Ni@TiO_(2) being twice that of the raw FA-Ni condensate.The Fourier transform infrared results suggested that formamide was adsorbed on TiO_(2) via the-CHO group,exposing-NH_(2) for potential interaction with Ni.As a result,Ni atoms were predispersed on the TiO_(2) surface.By contrast,the dispersion of Ni atoms was not enhanced by other metal oxides,such as Al_(2)O_(3),Fe_(2)O_(3),and ZnO,owing to the robust acidity of their surface sites.These metal oxides adsorbed formamide via-NH_(2),leading to the absence of extra-NH_(2) available for binding to Ni atoms.This study provides new insights into the development of appropriate substrates for single-atom catalysts.展开更多
A series of Ru supported on CeO_2 and Ce_(0.7)Zr_(0.3)O_2(CeZrO) was prepared by incipient-wet impregnation method and investigated in the catalytic wet oxidation of N,N-dimethyl formamide(DMF) in batch reactor. The p...A series of Ru supported on CeO_2 and Ce_(0.7)Zr_(0.3)O_2(CeZrO) was prepared by incipient-wet impregnation method and investigated in the catalytic wet oxidation of N,N-dimethyl formamide(DMF) in batch reactor. The physicochemical property of the catalysts was characterized by Brunauer-Emmett-Teller(BET), X-ray diffraction(XRD), H_2 temperature-programmed reduction(H_2-TPR), X-ray photoelectron spectroscopy(XPS) and thermogravimetry(TG). Compared with 3%Ru/CeO_2, 3%Ru/Ce_(0.7)Zr_(0.3)O_2 catalyst exhibits much higher performance for DMF degradation due to the promotion of Ru dispersion and the transfer of active oxygen, and 99% DMF conversion and 97% COD elimination are obtained at 453 K,2.5 MPa oxygen pressure after 5 h. The reaction mechanism of DMF degradation was suggested. The carbonaceous species deposition and oxidation of Ru can be responsible for catalyst deactivation. And the catalyst activity can be recovered by air calcination and H_2 reduction.展开更多
A highly efficient copper-catalyzed approach to form amide bonds from formamides and carboxylic acids was developed. This protocol shows broad substrate scopes and high yields in the presence of 1 mol% catalyst and 4....A highly efficient copper-catalyzed approach to form amide bonds from formamides and carboxylic acids was developed. This protocol shows broad substrate scopes and high yields in the presence of 1 mol% catalyst and 4.0 equiv, formamides.展开更多
The structures,the binding energies and the thermodynamic properties of formamide and hydroxyacetonitrile(HAN) dimers have been studied by means of the self\|consistent \%ab initio\% Hartree\|Fock and the second\|orde...The structures,the binding energies and the thermodynamic properties of formamide and hydroxyacetonitrile(HAN) dimers have been studied by means of the self\|consistent \%ab initio\% Hartree\|Fock and the second\|order Mφller\|Plesset correlation energy correction methods. The counterpoise procedure was used to check the basis set superposition error(BSSE) of the binding energies. There exist cyclic structures in a formamide dimer(Ⅰ),a HAN dimer(Ⅱ) and their heterodimer(Ⅲ). The corrected binding energies for dimers Ⅰ,Ⅱ and Ⅲ are respectively -45.53,-45.83 and -43.89 kJ/mol at the MP2/aug\|cc\|p VDZ//HF/\{aug\|cc\|p VDZ\} level. The change of the Gibbs free energies(Δ\%G\%) in the process of Ⅰ+Ⅱ→2Ⅲ was predicted to be -2.74 kJ/mol at 298.15 K. Dimer Ⅲ can be spontaneously produced in the mixture of formamide and HAN,which is in agreement with the experimental fact that most cyanohydrins are capable of interacting with dipeptide cyclo\|His\|Phe(CHP).展开更多
The formamide-titanium oxide interaction mechanism is a research target of great importance for understanding the elementary events of the origin of life: the synthesis of nucleoside bases and formation of biological ...The formamide-titanium oxide interaction mechanism is a research target of great importance for understanding the elementary events of the origin of life: the synthesis of nucleoside bases and formation of biological molecules needed for life. Titanium oxide (TiO2) can act as a strongly adsorbing surface or a catalytic material. In the present study, a comparative molecular dynamics analysis performed to clarify the adsorbing and diffusion properties of liquid formamide on a TiO2 surface in the presence of water molecules. The structural features of the formamide concentration effect (the accumulation of molecules) on a TiO2 surface in the presence and absence of water solvent are cleared up. Modification of the formamide diffusion abilities mediated by a water solvent is observed to correlate with the formamide-water concentration distribution on the surface.展开更多
Non-precious metal-nitrogen-carbon(MNC)electrocatalysts have gained tremendous attention as promising electrocatalysts for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).However,the most applicable s...Non-precious metal-nitrogen-carbon(MNC)electrocatalysts have gained tremendous attention as promising electrocatalysts for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).However,the most applicable strategies for the synthesis of MNC materials heavily rely on pyrolysis treatment,which may easily lead to metal aggregation and subsequent degradation of catalytic performance.Herein,we developed a pyrolysis-free strategy for preparing MNC materials,which was demonstrated by achieving ultrathin cobalt-nitrogen-carbon(Co NC)layer with dense atomically dispersed cobalt sites depositing on graphene oxide(GO)via simple treatment of Co salt and GO in formamide.The formamide-derived Co NC layer deposited on GO(termed as f-Co NC/GO)could be controlled in 1-2 nm thick.Remarkably,the f-CoNC/GO composite without pyrolysis exhibited excellent bifunctional performance toward ORR and OER,which was attributed to the dense atomically dispersed Co-Nxsites and improved conductivity by GO substrate.Furthermore,the f-CoNC/GO-assembled rechargeable Zn-air battery showed highly efficient and stable performance,demonstrating our pyrolysis-free method to be straightforward,cost-effective,and feasible for the scalable production of MNC electrocatalysts.展开更多
The hybrid calculations with ONIOM（B3LYP/6-31G＊：AM1） method were carried out on the tautomerization reaction of formamide to formamidic acid in the microcontainer-encapsulated state. The free-state tautomerization...The hybrid calculations with ONIOM（B3LYP/6-31G＊：AM1） method were carried out on the tautomerization reaction of formamide to formamidic acid in the microcontainer-encapsulated state. The free-state tautomerization process was also investigated with B3LYP/6-31G＊＊//B3LYP/6-31G＊ method for the purpose of comparison. Bare tautomerization, H20-assisted（single-H20 or multiple-HaO） and self-assisted mechanisms were all taken into consideration for the encapsulated state. The results show that only bare tautomerization and single-H2O catalysis mechanisms are possible to the encapsulated formamide tautomerization owing to the container＇s size confinement effect. Geometrical changes in the complexed container and vip molecules are discussed to deeply understand the complex＇s structural properties. The bare tautomerization barrier in the encapsulated state increases by 23.826 kJ/mol, accounting for 12% of the corresponding total energy barrier in the free state, and the increased values for the single-H2O catalysis process are 12.958 kJ/mol, accounting for 16% of the corresponding total energy barrier, respectively. This finding suggests that the encapsulation can make the tautomerization process slightly difficult.展开更多
The tautomerism of formamide has been investigated by ab initio calculation using RHF/4-31G basis set. The change in some physical properties along the reaction path is presented. In the study of molecular reaction ki...The tautomerism of formamide has been investigated by ab initio calculation using RHF/4-31G basis set. The change in some physical properties along the reaction path is presented. In the study of molecular reaction kinetics, we have calculated all the kinetic parameters according to statistical thermodynamics and transition state theory. The combination of kinetics analysis with IRC analysis has indicated that the tautomerism is concerted but the geometric changes are nonsynchronous; the lifetime of the transition state is short and the transition state is tight type; the formamide is more stable than formimidic acid; the kinetic rate constant of backward reaction is larger than that of the forward reaction in the range of temperature studied.展开更多
The proton transfer in the isolated, mono and dehydrated forms, isolated dimers of N-Hydroxy Methylen Formamide (NHMF) have been completely investigated in the present study using Density Functional Theory (DFT), M?ll...The proton transfer in the isolated, mono and dehydrated forms, isolated dimers of N-Hydroxy Methylen Formamide (NHMF) have been completely investigated in the present study using Density Functional Theory (DFT), M?ller-Plesset perturbation (MP2) and Hartree-Fock (HF) methods with the 6-31G* and 6-311G* basis sets. The barrier heights for both H2O-assisted and auto-assistance reactions are significantly lower than that of the bare tautomerization reaction from NHMF to N-Formyl Formamide (NFF), implying the importance of the superior catalytic effect of H2O in the monomer of NHMF and important role of HOCH= N-COH for the intramolecular proton transfer.展开更多
The research team headed by Ding Kuiling working in the State Key Laboratory of Metallorganic Chemistry at the CAS Shanghai Institute of Organic Chemistry by using the princer type ruthenium complex catalyst has succe...The research team headed by Ding Kuiling working in the State Key Laboratory of Metallorganic Chemistry at the CAS Shanghai Institute of Organic Chemistry by using the princer type ruthenium complex catalyst has successfully developed a new method for effectively synthesizing formamide compounds from CO_2,H2 and primary or secondary amines serving as the feedstocks.展开更多
The high spinning speed 1H magic angle spinning nuclear magnetic resonance (1H MAS NMR) technique was employed to distinguish the two groups of surface hy-droxyls of kaolinite and investigate the intercalation mechani...The high spinning speed 1H magic angle spinning nuclear magnetic resonance (1H MAS NMR) technique was employed to distinguish the two groups of surface hy-droxyls of kaolinite and investigate the intercalation mechanism of kaolinite/formamide compound. The proton chemical shifts of the inner hydroxyl and inner surface hydroxyl of kaolinte are in the range of δ-1.3--0.9 and δ 2.4-3.0 respectively. After formamide intercalation three proton peaks were detected. The proton peak of the inner surface hydrox-yls of the intercalation compound shifts to high-field with δ2.3-2.7, which is assigned to the formation of the hydrogen bond between the inner surface hydroxyl and formamide carbonyl group. Whereas, the proton peak of the inner hydroxyl shifts to δ-0.3 toward low-field, that is attributed to van der Waal’s effect between the inner hydroxyl proton and the amino group proton of the formamide which may be keyed into the ditrigonal hole of the kaolinite. The third peak, additional proton peak, is in the展开更多
Excess volumes （v^E）, ultrasonic velocities （u）, isentropic compressibility （△Ks） and viscosities （η） for the binary mixtures of dimethyl formamide （DMF） with 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2,...Excess volumes （v^E）, ultrasonic velocities （u）, isentropic compressibility （△Ks） and viscosities （η） for the binary mixtures of dimethyl formamide （DMF） with 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2,4-trichlorobenzene, o-chlorotoluene, m-chlorotoluene, p-chlorotoluene, o-nitrotoluene and m-nitrotoluene at 303.15 K were studied. Excess volume data exhibit an inversion in sign for the mixtures of dimethyl formamide with 1,2- and 1,3-dichlorobenzenes and the property is completely positive over the entire composition range for the mixtures of dimethyl formamide with 1,2,4-trichlorobenzene, o-nitrotoluene and m-nitrotoluene. On the other hand, the quantity is negative for the mixtures of dimethyl formamide with chlorotoluenes. Isentropic compressibility （Ks） has been computed for the same systems from precise sound velocity and density data. Further, deviation of isentropic com- pressibility （△Ks） from ideal behavior was also calculated. AKs values are negative over the entire volume fraction range in all the binary mixtures. The experimental sound velocity data were analysed in terms of Free Length Theory （FLT） and Collision Factor Theory （CFT）. The viscosity data were analysed on the basis of corresponding state approach. The measured data were discussed on the basis of intermolecular interactions between unlike molecules.展开更多
For the first time, Pd supported on natural palygorskite was developed for amine formylation with CO2 and H2. Both secondary and primary amines with diverse structures could be converted into the desired formamides at...For the first time, Pd supported on natural palygorskite was developed for amine formylation with CO2 and H2. Both secondary and primary amines with diverse structures could be converted into the desired formamides at < 100 °C, and good to excellent yields were obtained.展开更多
Activating MoS_(2) with atomic metal doping is promising to harvest desirable Pt-matched hydrogen evolution reaction(HER)catalytic performance.Herein,we developed an efficient method to access edgerich lattice-distort...Activating MoS_(2) with atomic metal doping is promising to harvest desirable Pt-matched hydrogen evolution reaction(HER)catalytic performance.Herein,we developed an efficient method to access edgerich lattice-distorted MoS_(2) for highly efficient HER via in-situ sulphuration of atomic Co/Mo species that were well-dispersed in a formamide-derived N-doped carbonaceous(f-NC)substrate.Apart from others,pre-embedding Co/Mo species in f-NC controls the release of metal sources upon annealing in S vapor,grafting the as-made MoS_(2) with merits of short-range crystallinity,distorted lattices,rich defects,and more edges exposed.The content of atomic Co species embedded in MoS_(2) reaches up to 2.85 at.%,and its atomic dispersion has been systematically confirmed by using XRD,HRTEM,XPS,and XAS characterizations.The Co-doped MoS_(2) sample exhibits excellent HER activity,achieving overpotentials of 67 and155 m V at j=10 m A cm^(-2) in 1.0 M KOH and 0.5 M H_(2)SO_(4),respectively.Density functional theory simulations suggest that,compared with free-doping MoS_(2),the edged Co doping is responsible for the significantly improved HER activity.Our method,in addition to providing reliable Pt-matched HER catalysts,may also inspire the general synthesis of edge-rich metal-doped metal chalcogenide for a wide range of energy conversion applications.展开更多
In this paper, formamide was firstly used as plasticizer to prepare thermoplastic starch (TPS), which could suppress the retrogradation of TPS by X-ray diffractometry (XRD) and show a good flexibility, but was weaker ...In this paper, formamide was firstly used as plasticizer to prepare thermoplastic starch (TPS), which could suppress the retrogradation of TPS by X-ray diffractometry (XRD) and show a good flexibility, but was weaker than conventional glycerol-plasticized TPS (GPTPS). When urea was introduced into plasticizer, both the retrogradation and mechanical properties were ameliorated. The tensile stress, strain and energy break of TPS plasticized by urea (wt. 20%) and formamide (wt.10%), respectively, reached 4.83 MPa, 104.6 % and 2.17 N-m (Newton-meter) after it had been stored at relative humidity (RH) 30% for one week.展开更多
Density,ultrasonic velocity and viscosity of imidazolinone derivatives are studied in dimethyl formamide(DMF) at 308.15 K.From the experimental data,various acoustical parameters,such as specific impedance Z,isentropi...Density,ultrasonic velocity and viscosity of imidazolinone derivatives are studied in dimethyl formamide(DMF) at 308.15 K.From the experimental data,various acoustical parameters,such as specific impedance Z,isentropic compressibilityκs,Rao's molar sound function Rm,van der Waals constant b,relaxation strength r,intermolecular free length Lf,internal pressureπ,solvation number Sn,relative association RA,etc.are evaluated,which helps in understanding the molecular interactions occurring in these solutions.展开更多
Design of supportive atomic sites with a controllably adjusted coordinating environment is essential to advancing the reduction of CO_(2) to value-added fuels and chemicals and to achieving carbon neutralization.Herei...Design of supportive atomic sites with a controllably adjusted coordinating environment is essential to advancing the reduction of CO_(2) to value-added fuels and chemicals and to achieving carbon neutralization.Herein,atomic Ni(Zn)sites that are uniquely coordinated with ternary Zn(Ni)/N/O ligands were successfully decorated on formamide-derived porous carbon nanomaterials,possibly forming an atomic structure of Ni(N_(2)O_(1))-Zn(N_(2)O_(1)),as studied by combining X-ray photoelectron spectroscopy and X-ray absorption spectroscopy.With the mediation of additional O coordination,the Ni-Zn dual site induces significantly decreased desorption of molecular CO.The NiZn-NC decorated with rich Ni(N_(2)O_(1))-Zn(N_(2)O_(1))sites remarkably gained>97%CO Faraday efficiency over a wide potential range of -0.8 to -1.1 V(relative to reversible hydrogen electrode).Density functional theory computations suggest that the N/O dual coordination effectively modulates the electronic structure of the Ni-Zn duplex and optimizes the adsorption and conversion properties of CO_(2) and subsequent intermediates.Different from the conventional pathway of using Ni as the active site in the Ni-Zn duplex,it is found that the Ni-neighboring Zn sites in the Ni(N_(2)O_(1))-Zn(N_(2)O_(1))coordination showed much lower energy barriers of the CO_(2) protonation step and the subsequent dehydroxylation step.展开更多
ForewordIt is well known that all electrical machines and equipmentsare made mainly of conducting materials,magnetic materials,struc-tural materials and insulating materials.Insulation materials are sub-jected to mech...ForewordIt is well known that all electrical machines and equipmentsare made mainly of conducting materials,magnetic materials,struc-tural materials and insulating materials.Insulation materials are sub-jected to mechanical,thermal and electrical stresses and exposed tomoisture,dirt,chemical corrosion and radiation.The combined ac-tion,intensity and duration of such stresses and effects set a limit展开更多
NaY zeolite functionalized by sulfamic acid/Cu（OAc）_2[NaY/SA/Cu（Ⅱ）] was synthesized and used as a new,efficient and recyclable catalyst for preparation of formamides. This novel organic-inorganic hybrid catalyst ...NaY zeolite functionalized by sulfamic acid/Cu（OAc）_2[NaY/SA/Cu（Ⅱ）] was synthesized and used as a new,efficient and recyclable catalyst for preparation of formamides. This novel organic-inorganic hybrid catalyst was characterized by several techniques such as FT-IR, XRD, SEM, EDX and TG analysis.Chemoselectivity, easy procedure, excellent yields, very short reaction times, solvent-free and mild reaction conditions are some benefits of this new protocol.展开更多
Although MXene has attracted great interest in diverse fields,it is susceptible to oxidation in water(H_(2)O)with transition metal ions such as Co^(2+),Fe^(2+),and Cu^(2+),which is pronounced at high temperatures.This...Although MXene has attracted great interest in diverse fields,it is susceptible to oxidation in water(H_(2)O)with transition metal ions such as Co^(2+),Fe^(2+),and Cu^(2+),which is pronounced at high temperatures.This impedes the preparation of MXene-based composites and their functional applications.Here,this study revealed that Co^(2+)increases the maximum and average atomic charge of H in H_(2)O to improve the reactivity of H_(2)O,which leads to the fact that Co^(2+)catalyzes the oxidation of Ti_(3)C_(2)T_(x)MXene.Furthermore,the addition of N,Ndimethyl formamide(DMF)reduces theH_(2)Oactivity and improves the oxidation stability of Ti_(3)C_(2)T_(x)in the presence of Co^(2+)via preferentially forming coordination bonds with Co^(2+).This strategy is also effective in enhancing the oxidation tolerance of Ti_(3)C_(2)T_(x)to Fe^(2+)in H_(2)O.Moreover,it is feasible to enhance the oxidation stability of Ti2CTx MXene in H_(2)O with the existence of Co^(2+).By virtue of these,the CoO/Ti_(3)C_(2)T_(x)composite was successfully prepared without obvious Ti_(3)C_(2)T_(x)oxidation,which is desirable to harness the advantages of Ti_(3)C_(2)T_(x)as the complementary component for lithium-ion batteries.This work provides a straightforward paradigm to enhance the oxidation resistance of MXene in H_(2)O in the presence of transition metal ions and at high temperatures,which opens a new vista to use MXene for target applications.展开更多
基金supported by the National Natural Science Foundation of China(No.42077299)the Innovation Program of Chinese Academy of Agricultural Sciences(No.Y2024QC29).
文摘Formamide condensation with Ni can generate the N–C structure,widely recognized as an efficient catalyst for electrocatalytic CO_(2) reduction reaction(CO_(2)RR).To improve the utilization efficiency of Ni atoms,we introduced metal oxides as substrates to modulate the growth of a formamide-Ni(FA-Ni)condensate.FA-Ni@TiO_(2) demonstrated 2.8 times higher partial CO current density and Ni turnover frequency than FA-Ni,which were also higher than those of other FA-Ni@metal oxides,including ZrO_(2),Al_(2)O_(3),Fe_(2)O_(3),and ZnO.The improved performance of CO_(2)RR can be attributed to the Ni content exposed on FA-Ni@TiO_(2) being twice that of the raw FA-Ni condensate.The Fourier transform infrared results suggested that formamide was adsorbed on TiO_(2) via the-CHO group,exposing-NH_(2) for potential interaction with Ni.As a result,Ni atoms were predispersed on the TiO_(2) surface.By contrast,the dispersion of Ni atoms was not enhanced by other metal oxides,such as Al_(2)O_(3),Fe_(2)O_(3),and ZnO,owing to the robust acidity of their surface sites.These metal oxides adsorbed formamide via-NH_(2),leading to the absence of extra-NH_(2) available for binding to Ni atoms.This study provides new insights into the development of appropriate substrates for single-atom catalysts.
基金This project supported by the National Key Research and Development Program of China(2016YFC0204300)the National Natural Science Foundation of China(21171055,21333003,21571061)+1 种基金the"Shu Guang"Project of the Shanghai Municipal Education Commission(12SG29)the Commission of Science and Technology of Shanghai Municipality(15DZ1205305)
文摘A series of Ru supported on CeO_2 and Ce_(0.7)Zr_(0.3)O_2(CeZrO) was prepared by incipient-wet impregnation method and investigated in the catalytic wet oxidation of N,N-dimethyl formamide(DMF) in batch reactor. The physicochemical property of the catalysts was characterized by Brunauer-Emmett-Teller(BET), X-ray diffraction(XRD), H_2 temperature-programmed reduction(H_2-TPR), X-ray photoelectron spectroscopy(XPS) and thermogravimetry(TG). Compared with 3%Ru/CeO_2, 3%Ru/Ce_(0.7)Zr_(0.3)O_2 catalyst exhibits much higher performance for DMF degradation due to the promotion of Ru dispersion and the transfer of active oxygen, and 99% DMF conversion and 97% COD elimination are obtained at 453 K,2.5 MPa oxygen pressure after 5 h. The reaction mechanism of DMF degradation was suggested. The carbonaceous species deposition and oxidation of Ru can be responsible for catalyst deactivation. And the catalyst activity can be recovered by air calcination and H_2 reduction.
基金supported by the National Natural Science Foundation of China(No.21372176)Tongji University 985 Phase Ⅲ funds+1 种基金Pujiang Project of Shanghai Science and Technology Commission(No.11 J1409800)the Program for Professor of Special Appointment(Eastern Scholar) at Shanghai Institutions of Higher Learning
文摘A highly efficient copper-catalyzed approach to form amide bonds from formamides and carboxylic acids was developed. This protocol shows broad substrate scopes and high yields in the presence of 1 mol% catalyst and 4.0 equiv, formamides.
文摘The structures,the binding energies and the thermodynamic properties of formamide and hydroxyacetonitrile(HAN) dimers have been studied by means of the self\|consistent \%ab initio\% Hartree\|Fock and the second\|order Mφller\|Plesset correlation energy correction methods. The counterpoise procedure was used to check the basis set superposition error(BSSE) of the binding energies. There exist cyclic structures in a formamide dimer(Ⅰ),a HAN dimer(Ⅱ) and their heterodimer(Ⅲ). The corrected binding energies for dimers Ⅰ,Ⅱ and Ⅲ are respectively -45.53,-45.83 and -43.89 kJ/mol at the MP2/aug\|cc\|p VDZ//HF/\{aug\|cc\|p VDZ\} level. The change of the Gibbs free energies(Δ\%G\%) in the process of Ⅰ+Ⅱ→2Ⅲ was predicted to be -2.74 kJ/mol at 298.15 K. Dimer Ⅲ can be spontaneously produced in the mixture of formamide and HAN,which is in agreement with the experimental fact that most cyanohydrins are capable of interacting with dipeptide cyclo\|His\|Phe(CHP).
文摘The formamide-titanium oxide interaction mechanism is a research target of great importance for understanding the elementary events of the origin of life: the synthesis of nucleoside bases and formation of biological molecules needed for life. Titanium oxide (TiO2) can act as a strongly adsorbing surface or a catalytic material. In the present study, a comparative molecular dynamics analysis performed to clarify the adsorbing and diffusion properties of liquid formamide on a TiO2 surface in the presence of water molecules. The structural features of the formamide concentration effect (the accumulation of molecules) on a TiO2 surface in the presence and absence of water solvent are cleared up. Modification of the formamide diffusion abilities mediated by a water solvent is observed to correlate with the formamide-water concentration distribution on the surface.
基金financially supported by the National Natural Science Foundation of China(NSFC,21520102002,91622116,and 21701101)the National Key Research and Development Project(2016YFF0204402)+2 种基金the Fundamental Research Funds for the Central Universitiesthe Long-Term Subsidy Mechanism from the Ministry of Finance and the Ministry of Education of Chinathe Shandong Scientific Research Awards Foundation for Outstanding Young Scientists(ZR2018JL010)。
文摘Non-precious metal-nitrogen-carbon(MNC)electrocatalysts have gained tremendous attention as promising electrocatalysts for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).However,the most applicable strategies for the synthesis of MNC materials heavily rely on pyrolysis treatment,which may easily lead to metal aggregation and subsequent degradation of catalytic performance.Herein,we developed a pyrolysis-free strategy for preparing MNC materials,which was demonstrated by achieving ultrathin cobalt-nitrogen-carbon(Co NC)layer with dense atomically dispersed cobalt sites depositing on graphene oxide(GO)via simple treatment of Co salt and GO in formamide.The formamide-derived Co NC layer deposited on GO(termed as f-Co NC/GO)could be controlled in 1-2 nm thick.Remarkably,the f-CoNC/GO composite without pyrolysis exhibited excellent bifunctional performance toward ORR and OER,which was attributed to the dense atomically dispersed Co-Nxsites and improved conductivity by GO substrate.Furthermore,the f-CoNC/GO-assembled rechargeable Zn-air battery showed highly efficient and stable performance,demonstrating our pyrolysis-free method to be straightforward,cost-effective,and feasible for the scalable production of MNC electrocatalysts.
基金Supported by the Special Research Fund for the Doctoral Program of Higher Education of China(No.20040010008)the Scientific Research Fund of Beijing University of Chemical Technology, China(No.QN0411).
文摘The hybrid calculations with ONIOM（B3LYP/6-31G＊：AM1） method were carried out on the tautomerization reaction of formamide to formamidic acid in the microcontainer-encapsulated state. The free-state tautomerization process was also investigated with B3LYP/6-31G＊＊//B3LYP/6-31G＊ method for the purpose of comparison. Bare tautomerization, H20-assisted（single-H20 or multiple-HaO） and self-assisted mechanisms were all taken into consideration for the encapsulated state. The results show that only bare tautomerization and single-H2O catalysis mechanisms are possible to the encapsulated formamide tautomerization owing to the container＇s size confinement effect. Geometrical changes in the complexed container and vip molecules are discussed to deeply understand the complex＇s structural properties. The bare tautomerization barrier in the encapsulated state increases by 23.826 kJ/mol, accounting for 12% of the corresponding total energy barrier in the free state, and the increased values for the single-H2O catalysis process are 12.958 kJ/mol, accounting for 16% of the corresponding total energy barrier, respectively. This finding suggests that the encapsulation can make the tautomerization process slightly difficult.
文摘The tautomerism of formamide has been investigated by ab initio calculation using RHF/4-31G basis set. The change in some physical properties along the reaction path is presented. In the study of molecular reaction kinetics, we have calculated all the kinetic parameters according to statistical thermodynamics and transition state theory. The combination of kinetics analysis with IRC analysis has indicated that the tautomerism is concerted but the geometric changes are nonsynchronous; the lifetime of the transition state is short and the transition state is tight type; the formamide is more stable than formimidic acid; the kinetic rate constant of backward reaction is larger than that of the forward reaction in the range of temperature studied.
文摘The proton transfer in the isolated, mono and dehydrated forms, isolated dimers of N-Hydroxy Methylen Formamide (NHMF) have been completely investigated in the present study using Density Functional Theory (DFT), M?ller-Plesset perturbation (MP2) and Hartree-Fock (HF) methods with the 6-31G* and 6-311G* basis sets. The barrier heights for both H2O-assisted and auto-assistance reactions are significantly lower than that of the bare tautomerization reaction from NHMF to N-Formyl Formamide (NFF), implying the importance of the superior catalytic effect of H2O in the monomer of NHMF and important role of HOCH= N-COH for the intramolecular proton transfer.
文摘The research team headed by Ding Kuiling working in the State Key Laboratory of Metallorganic Chemistry at the CAS Shanghai Institute of Organic Chemistry by using the princer type ruthenium complex catalyst has successfully developed a new method for effectively synthesizing formamide compounds from CO_2,H2 and primary or secondary amines serving as the feedstocks.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 40072014)by the Foundation of State Key Laboratory for Physical Chemistry of Solid Surfaces in Xiamen University (Grant No. 9911).
文摘The high spinning speed 1H magic angle spinning nuclear magnetic resonance (1H MAS NMR) technique was employed to distinguish the two groups of surface hy-droxyls of kaolinite and investigate the intercalation mechanism of kaolinite/formamide compound. The proton chemical shifts of the inner hydroxyl and inner surface hydroxyl of kaolinte are in the range of δ-1.3--0.9 and δ 2.4-3.0 respectively. After formamide intercalation three proton peaks were detected. The proton peak of the inner surface hydrox-yls of the intercalation compound shifts to high-field with δ2.3-2.7, which is assigned to the formation of the hydrogen bond between the inner surface hydroxyl and formamide carbonyl group. Whereas, the proton peak of the inner hydroxyl shifts to δ-0.3 toward low-field, that is attributed to van der Waal’s effect between the inner hydroxyl proton and the amino group proton of the formamide which may be keyed into the ditrigonal hole of the kaolinite. The third peak, additional proton peak, is in the
文摘Excess volumes （v^E）, ultrasonic velocities （u）, isentropic compressibility （△Ks） and viscosities （η） for the binary mixtures of dimethyl formamide （DMF） with 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2,4-trichlorobenzene, o-chlorotoluene, m-chlorotoluene, p-chlorotoluene, o-nitrotoluene and m-nitrotoluene at 303.15 K were studied. Excess volume data exhibit an inversion in sign for the mixtures of dimethyl formamide with 1,2- and 1,3-dichlorobenzenes and the property is completely positive over the entire composition range for the mixtures of dimethyl formamide with 1,2,4-trichlorobenzene, o-nitrotoluene and m-nitrotoluene. On the other hand, the quantity is negative for the mixtures of dimethyl formamide with chlorotoluenes. Isentropic compressibility （Ks） has been computed for the same systems from precise sound velocity and density data. Further, deviation of isentropic com- pressibility （△Ks） from ideal behavior was also calculated. AKs values are negative over the entire volume fraction range in all the binary mixtures. The experimental sound velocity data were analysed in terms of Free Length Theory （FLT） and Collision Factor Theory （CFT）. The viscosity data were analysed on the basis of corresponding state approach. The measured data were discussed on the basis of intermolecular interactions between unlike molecules.
基金supported by the National Natural Science Foundation of China(91745106,21633013)the Major Projects of the National Natural Science Foundation of Gansu,China(18JR4RA001)+1 种基金the Youth Innovation Promotion Association CAS(2019409)Fujian Institute of Innovation,CAS and Key Research Program of Frontier Sciences of CAS(QYZDJ-SSW-SLH051)~~
文摘For the first time, Pd supported on natural palygorskite was developed for amine formylation with CO2 and H2. Both secondary and primary amines with diverse structures could be converted into the desired formamides at < 100 °C, and good to excellent yields were obtained.
基金financially supported by the National Natural Science Foundation of China(22071137)。
文摘Activating MoS_(2) with atomic metal doping is promising to harvest desirable Pt-matched hydrogen evolution reaction(HER)catalytic performance.Herein,we developed an efficient method to access edgerich lattice-distorted MoS_(2) for highly efficient HER via in-situ sulphuration of atomic Co/Mo species that were well-dispersed in a formamide-derived N-doped carbonaceous(f-NC)substrate.Apart from others,pre-embedding Co/Mo species in f-NC controls the release of metal sources upon annealing in S vapor,grafting the as-made MoS_(2) with merits of short-range crystallinity,distorted lattices,rich defects,and more edges exposed.The content of atomic Co species embedded in MoS_(2) reaches up to 2.85 at.%,and its atomic dispersion has been systematically confirmed by using XRD,HRTEM,XPS,and XAS characterizations.The Co-doped MoS_(2) sample exhibits excellent HER activity,achieving overpotentials of 67 and155 m V at j=10 m A cm^(-2) in 1.0 M KOH and 0.5 M H_(2)SO_(4),respectively.Density functional theory simulations suggest that,compared with free-doping MoS_(2),the edged Co doping is responsible for the significantly improved HER activity.Our method,in addition to providing reliable Pt-matched HER catalysts,may also inspire the general synthesis of edge-rich metal-doped metal chalcogenide for a wide range of energy conversion applications.
文摘In this paper, formamide was firstly used as plasticizer to prepare thermoplastic starch (TPS), which could suppress the retrogradation of TPS by X-ray diffractometry (XRD) and show a good flexibility, but was weaker than conventional glycerol-plasticized TPS (GPTPS). When urea was introduced into plasticizer, both the retrogradation and mechanical properties were ameliorated. The tensile stress, strain and energy break of TPS plasticized by urea (wt. 20%) and formamide (wt.10%), respectively, reached 4.83 MPa, 104.6 % and 2.17 N-m (Newton-meter) after it had been stored at relative humidity (RH) 30% for one week.
文摘Density,ultrasonic velocity and viscosity of imidazolinone derivatives are studied in dimethyl formamide(DMF) at 308.15 K.From the experimental data,various acoustical parameters,such as specific impedance Z,isentropic compressibilityκs,Rao's molar sound function Rm,van der Waals constant b,relaxation strength r,intermolecular free length Lf,internal pressureπ,solvation number Sn,relative association RA,etc.are evaluated,which helps in understanding the molecular interactions occurring in these solutions.
基金National Natural Science Foundation of China,Grant/Award Number:22071137Key Projects of China National Key R&D Plan,Grant/Award Number:2018YFE0118200+1 种基金Key Projects of Shandong Key R&D plan,Grant/Award Number:2019JZZY010506Taishan Scholar Foundation,Grant/Award Number:tspd20210308。
文摘Design of supportive atomic sites with a controllably adjusted coordinating environment is essential to advancing the reduction of CO_(2) to value-added fuels and chemicals and to achieving carbon neutralization.Herein,atomic Ni(Zn)sites that are uniquely coordinated with ternary Zn(Ni)/N/O ligands were successfully decorated on formamide-derived porous carbon nanomaterials,possibly forming an atomic structure of Ni(N_(2)O_(1))-Zn(N_(2)O_(1)),as studied by combining X-ray photoelectron spectroscopy and X-ray absorption spectroscopy.With the mediation of additional O coordination,the Ni-Zn dual site induces significantly decreased desorption of molecular CO.The NiZn-NC decorated with rich Ni(N_(2)O_(1))-Zn(N_(2)O_(1))sites remarkably gained>97%CO Faraday efficiency over a wide potential range of -0.8 to -1.1 V(relative to reversible hydrogen electrode).Density functional theory computations suggest that the N/O dual coordination effectively modulates the electronic structure of the Ni-Zn duplex and optimizes the adsorption and conversion properties of CO_(2) and subsequent intermediates.Different from the conventional pathway of using Ni as the active site in the Ni-Zn duplex,it is found that the Ni-neighboring Zn sites in the Ni(N_(2)O_(1))-Zn(N_(2)O_(1))coordination showed much lower energy barriers of the CO_(2) protonation step and the subsequent dehydroxylation step.
文摘ForewordIt is well known that all electrical machines and equipmentsare made mainly of conducting materials,magnetic materials,struc-tural materials and insulating materials.Insulation materials are sub-jected to mechanical,thermal and electrical stresses and exposed tomoisture,dirt,chemical corrosion and radiation.The combined ac-tion,intensity and duration of such stresses and effects set a limit
基金Arak University for financial support for this work
文摘NaY zeolite functionalized by sulfamic acid/Cu（OAc）_2[NaY/SA/Cu（Ⅱ）] was synthesized and used as a new,efficient and recyclable catalyst for preparation of formamides. This novel organic-inorganic hybrid catalyst was characterized by several techniques such as FT-IR, XRD, SEM, EDX and TG analysis.Chemoselectivity, easy procedure, excellent yields, very short reaction times, solvent-free and mild reaction conditions are some benefits of this new protocol.
基金National Natural Science Foundation of China,Grant/Award Numbers:52272295,52071137,51977071,51802040,21802020Science and Technology Innovation Program of Hunan Province,Grant/Award Numbers:2021RC3066,2021RC3067+1 种基金Natural Science Foundation of Hunan Province,Grant/Award Number:2020JJ3004Fundamental Research Funds for the Central Universities。
文摘Although MXene has attracted great interest in diverse fields,it is susceptible to oxidation in water(H_(2)O)with transition metal ions such as Co^(2+),Fe^(2+),and Cu^(2+),which is pronounced at high temperatures.This impedes the preparation of MXene-based composites and their functional applications.Here,this study revealed that Co^(2+)increases the maximum and average atomic charge of H in H_(2)O to improve the reactivity of H_(2)O,which leads to the fact that Co^(2+)catalyzes the oxidation of Ti_(3)C_(2)T_(x)MXene.Furthermore,the addition of N,Ndimethyl formamide(DMF)reduces theH_(2)Oactivity and improves the oxidation stability of Ti_(3)C_(2)T_(x)in the presence of Co^(2+)via preferentially forming coordination bonds with Co^(2+).This strategy is also effective in enhancing the oxidation tolerance of Ti_(3)C_(2)T_(x)to Fe^(2+)in H_(2)O.Moreover,it is feasible to enhance the oxidation stability of Ti2CTx MXene in H_(2)O with the existence of Co^(2+).By virtue of these,the CoO/Ti_(3)C_(2)T_(x)composite was successfully prepared without obvious Ti_(3)C_(2)T_(x)oxidation,which is desirable to harness the advantages of Ti_(3)C_(2)T_(x)as the complementary component for lithium-ion batteries.This work provides a straightforward paradigm to enhance the oxidation resistance of MXene in H_(2)O in the presence of transition metal ions and at high temperatures,which opens a new vista to use MXene for target applications.
