Solubility and solution thermodynamics of ammonium dihydrogen phosphate in the water–methanol system

The solubility of ammonium dihydrogen phosphate(MAP)in the water–methanol system is essential for antisolvent crystallization studies.To investigate the effect of methanol on the solubility of MAP in water,the solubility of MAP in the water–methanol system was determined by dynamic method and static equilibrium method at temperatures ranging from 293.2 to 343.2 K at atmospheric pressure.Results showed that the solubility of MAP increased with the increase of temperature and the increase of water mole fraction in the water–methanol system.The experimental solubility data were correlated with the modified Apelblat equation,the combined nearly ideal binary solvent/Redlich–Kister(CNIBS/R–K)model and the Jouyban–Acree model.The calculated results based on these three models were in very good agreement with the experimental data with the average relative deviations of 0.65%,0.97%,and 5.38%,respectively.Simultaneously,the thermodynamic properties of the MAP dissolution process in the water–methanol system,including Gibbs energy change,enthalpy,and entropy were obtained by the Van’t Hoff equation,which can be used to assess the crystallization process.

Heat of Boron Trifluoride–Methanol System Determined by Bunsen Ice Calorimeter

The complex heat of BF_3 with methanol was measured by utilizing the principle of the Bunsen ice calorimeter. The complex heat of BF_3 –methanol was found to be 49.2 and 58.1 kJ/mol when the molar ratio of BF_3 to methanol was 1:2 and 1:1,respectively. In addition,the complex heat of BF_3 –anisole was also measured to test the apparatus error. The BF_3 –anisole result showed a calorimeter value of 53.1 kJ/mol with a system error of 2.3% as compared with the value reported in the literature. The mechanism of the reaction of BF_3 and methanol was interpreted based on our obtained results. This apparatus is useful and suitable for measuring the heat of other liquid–gas and liquid–liquid reactions.

Modeling and analysis of air combustion and steam regeneration in methanol to olefins processes

Light olefins is the incredibly important materials in chemical industry.Methanol to olefins(MTO),which provides a non-oil route for light olefins production,received considerable attention in the past decades.However,the catalyst deactivation is an inevitable feature in MTO processes,and regeneration,therefore,is one of the key steps in industrial MTO processes.Traditionally the MTO catalyst is regenerated by removing the deposited coke via air combustion,which unavoidably transforms coke into carbon dioxide and reduces the carbon utilization efficiency.Recent study shows that the coke species over MTO catalyst can be regenerated via steam,which can promote the light olefins yield as the deactivated coke species can be essentially transferred to industrially useful synthesis gas,is a promising pathway for further MTO processes development.In this work,we modelled and analyzed these two MTO regeneration methods in terms of carbon utilization efficiency and technology economics.As shown,the steam regeneration could achieve a carbon utilization efficiency of 84.31%,compared to 74.74%for air combustion regeneration.The MTO processes using steam regeneration can essentially achieve the near-zero carbon emission.In addition,light olefins production of the MTO processes using steam regeneration is 12.81%higher than that using air combustion regeneration.In this regard,steam regeneration could be considered as a potential yet promising regeneration method for further MTO processes,showing not only great environmental benefits but also competitive economic performance.

Precision tuning of highly efficient Pt-based ternary alloys on nitrogen-doped multi-wall carbon nanotubes for methanol oxidation reaction

The electrochemical methanol oxidation is a crucial reaction in the conversion of renewable energy.To enable the widespread adoption of direct methanol fuel cells(DMFCs),it is essential to create and engineer catalysts that are both highly effective and robust for conducting the methanol oxidation reaction(MOR).In this work,trimetallic PtCoRu electrocatalysts on nitrogen-doped carbon and multi-wall carbon nanotubes(PtCoRu@NC/MWCNTs)were prepared through a two-pot synthetic strategy.The acceleration of CO oxidation to CO_(2) and the blocking of CO reduction on adjacent Pt active sites were attributed to the crucial role played by cobalt atoms in the as-prepared electrocatalysts.The precise control of Co atoms loading was achieved through precursor stoichiometry.Various physicochemical techniques were employed to analyze the morphology,element composition,and electronic state of the catalyst.Electrochemical investigations and theoretical calculations confirmed that the Pt_(1)Co_(3)Ru_(1)@NC/MWCNTs exhibit excellent electrocatalytic performance and durability for the process of MOR.The enhanced MOR activity can be attributed to the synergistic effect between the multiple elements resulting from precisely controlled Co loading content on surface of the electrocatalyst,which facilitates efficient charge transfer.This interaction between the multiple components also modifies the electronic structures of active sites,thereby promoting the conversion of intermediates and accelerating the MOR process.Thus,achieving precise control over Co loading in PtCoRu@NC/MWCNTs would enable the development of high-performance catalysts for DMFCs.

Efficient and stable PtFe alloy catalyst for electrocatalytic methanol oxidation with high resistance to CO

Direct methanol fuel cells(DMFC) are widely considered to be an ideal green energy conversion device but their widespread applications are limited by the high price of the Pt-based catalysts and the instability in terms of surface CO toxicity in long-term operation.Herein,the PtFe alloy nanoparticles(NPs) with small particle size(~4.12 nm) supported on carbon black catalysts with different Pt/Fe atomic ratios(Pt_(1)Fe_(2)/C,Pt_(3)Fe_(4)/C,Pt_(1)Fe_(1)/C,and Pt_(2)Fe_(1)/C) are successfully prepared for enhanced anti-CO poisoning during methanol oxidation reaction(MOR).The optimal atomic ratio of Pt/Fe for the MOR is 1:2,and the mass activity of Pt_(1)Fe_(2)/C(5.40 A mg_(Pt)^(-1)) is 13.5 times higher than that of conventional commercial Pt/C(Pt/C-JM)(0.40 A mg_(Pt)^(-1)).The introduction of Fe into the Pt lattice forms the PtFe alloy phase,and the electron density of Pt is reduced after forming the PtFe alloy.In-situ Fourier transform infrared results indicate that the addition of oxyphilic metal Fe has reduced the adsorption of reactant molecules on Pt during the MOR.The doping of Fe atoms helps to desorb toxic intermediates and regenerate Pt active sites,promoting the cleavage of C-O bonds with good selectivity of CO_(2)(58.1%).Moreover,the Pt_(1)Fe_(2)/C catalyst exhibits higher CO tolerance,methanol electrooxidation activity,and long-term stability than other Pt_(x)Fe_(y)/C catalysts.

Realizing methanol synthesis from CO and water via the synergistic effect of Cu^(0)/Cu^(+)over Cu/ZrO_(2) catalyst

The optimizing utilization of ca rbon resources has drawn wide attention all over the world,while exploiting the high-efficiency catalytic routes remains a challenge.Here,a direct methanol synthesis route is realized from pure CO and H_(2)O over 10%Cu/t-ZrO_(2) catalyst,where the time yield of methanol is144.43 mmol mol_(Cu)^(-1)h^(-1)and the methanol selectivity in hydrocarbons is 100%,The Cu species highly dispersed in the t-ZrO_(2) support lead parts of them in the cationic state.The Cu^(+)sites contribute to the dissociation of H_(2)O,providing the H*source for methanol synthesis,while the formed Cu^(0) sites promote the absorption and transfer of H*during the reaction.Moreover,the H_(2)O is even a better H resource than H_(2) due to its better dissociation effectivity in this catalytic system.The present work offers a new approach for methanol synthesis from CO and new insight into the process of supplying H donor.

Low carbon alcohol fuel electrolysis of hydrogen generation catalyzed by a novel and effective Pt–CoTe/C bifunctional catalyst system

Low carbon alcohol fuels electrolysis under ambient conditions is promising for green hydrogen generation instead of the traditional alcohol fuels steam reforming technique,and highly efficient bifunctional catalysts for membrane electrode fabrication are required to drive the electrolysis reactions.Herein,the efficient catalytic promotion effect of a novel catalyst promoter,CoTe,on Pt is demonstrated for low carbon alcohol fuels of methanol and ethanol electrolysis for hydrogen generation.Experimental and density functional theory calculation results indicate that the optimized electronic structure of Pt–CoTe/C resulting from the synergetic effect between Pt and CoTe further regulates the adsorption energies of CO and H*that enhances the catalytic ability for methanol and ethanol electrolysis.Moreover,the good water activation ability of CoTe and the strong electronic effect of Pt and CoTe increased the tolerance ability to the poisoning species as demonstrated by the CO-stripping technique.The high catalytic kinetics and stability,as well as the promotion effect,were also carefully discussed.Specifically,71.9%and 75.5%of the initial peak current density was maintained after 1000 CV cycles in acid electrolyte for methanol and ethanol oxidation;and a low overpotential of 30 and 35 mV was required to drive the hydrogen evolution reaction in methanol and ethanol solution at the current density of 10 mA cm^(-2).In the two-electrode system for alcohol fuels electrolysis,using the optimal Pt–CoTe/C catalyst as bi-functional catalysts,the cell potential of 0.66 V(0.67 V)was required to achieve 10 mA cm^(-2) for methanol(ethanol)electrolysis,much smaller than that of water electrolysis(1.76 V).The current study offers a novel platform for hydrogen generation via low carbon alcohol fuel electrolysis,and the result is helpful to the catalysis mechanism understanding of Pt assisted by the novel promoter.

Interfacial Electronic Modulation of Dual-Monodispersed Pt–Ni_(3)S_(2) as Efficacious Bi-Functional Electrocatalysts for Concurrent H_(2) Evolution and Methanol Selective Oxidation

Constructing the efficacious and applicable bifunctional electrocatalysts and establishing out the mechanisms of organic electro-oxidation by replacing anodic oxygen evolution reaction(OER) are critical to the development of electrochemicallydriven technologies for efficient hydrogen production and avoid CO_(2) emission. Herein, the hetero-nanocrystals between monodispersed Pt(~ 2 nm) and Ni_(3)S_(2)(~ 9.6 nm) are constructed as active electrocatalysts through interfacial electronic modulation, which exhibit superior bi-functional activities for methanol selective oxidation and H_(2) generation. The experimental and theoretical studies reveal that the asymmetrical charge distribution at Pt–Ni_(3)S_(2) could be modulated by the electronic interaction at the interface of dual-monodispersed heterojunctions, which thus promote the adsorption/desorption of the chemical intermediates at the interface. As a result, the selective conversion from CH_(3)OH to formate is accomplished at very low potentials(1.45 V) to attain 100 m A cm^(-2) with high electronic utilization rate(~ 98%) and without CO_(2) emission. Meanwhile, the Pt–Ni_(3)S_(2) can simultaneously exhibit a broad potential window with outstanding stability and large current densities for hydrogen evolution reaction(HER) at the cathode. Further, the excellent bi-functional performance is also indicated in the coupled methanol oxidation reaction(MOR)//HER reactor by only requiring a cell voltage of 1.60 V to achieve a current density of 50 m A cm^(-2) with good reusability.

CO_(2) hydrogenation to methanol over the copper promoted In_(2)O_(3) catalyst

The metal promoted In_(2)O_(3) catalysts for CO_(2) hydrogenation to methanol have attracted wide attention because of their high activity with high methanol selectivity.However,there was still no experimental confirmation if copper could be a good promoter for In_(2)O_(3).Herein,the Cu promoted In_(2)O_(3) catalyst was prepared using a deposition-precipitation method.Such prepared Cu/In_(2)O_(3) catalyst shows significantly higher CO_(2) conversion and space time yield(STY)of methanol,compared to the un-promoted In_(2)O_(3) catalyst.The loading of Cu facilitates the activation of both H_(2) and CO_(2) with the interface between the Cu cluster and defective In_(2)O_(3) as the active site.The Cu/In_(2)O_(3) catalyst takes the CO hydrogenation pathway for methanol synthesis from CO_(2) hydrogenation.It exhibits a unique size effect on the CO adsorption.At temperatures below 250℃,CO adsorption on Cu/In_(2)O_(3) is stronger than that on In_(2)O_(3),causing higher methanol selectivity.With increasing temperatu res,the Cu catalyst aggregates,which leads to the formation of weak CO adsorption site and causes a decrease in the methanol selectivity.Compared with other metal promoted In_(2)O_(3) catalysts,it can be concluded that the catalyst with stronger CO adsorption possesses higher methanol selectivity.

Pt nanoclusters modified porous g-C_(3)N_(4)nanosheets to significantly enhance hydrogen production by photocatalytic water reforming of methanol

For the use of green hydrogen energy,it is crucial to have efficient photocatalytic activity for hydrogen generation by water reforming of methanol under mild conditions.Much attention has been paid to gC_(3)N_(4)as a promising photocatalyst for the generation of hydrogen.To improve the separation of photogenerated charge,porous nanosheet g-C_(3)N_(4)was modified with Pt nanoclusters(Pt/g-C_(3)N_(4))through impregnation and following photo-induced reduction.This catalyst showed excellent photocatalytic activity of water reforming of methanol fo r hydrogen production with a 17.12 mmol·g^(-1)·h^(-1)rate at room temperature,which was 311 times higher than that of the unmodified g-C_(3)N_(4).The strong interactions of Pt-N in Pt/g-C_(3)N_(4)constructed effective electron transfer channels to promote the separation of photogenerated electrons and holes effectively.In addition,in-situ infrared spectroscopy was used to investigate the intermediates of the hydrogen production reaction,which proved that methanol and water eventually turn into H_(2)and CO_(2)via formaldehyde and formate.This study provides insights for understanding the photocatalytic hydrogen production in the water reforming of methanol.

The Effects of the Geometry of a Current Collector with an Equal Open Ratio on Output Power of a Direct Methanol Fuel Cell

The open ratio of a current collector has a great impact on direct methanol fuel cell(DMFC)performance.Although a number of studies have investigated the influence of the open ratio of DMFC current collectors,far too little attention has been given to how geometry(including the shape and feature size of the flow field)affects a current collector with an equal open ratio.In this paper,perforated and parallel current collectors with an equal open ratio of 50%and different feature sizes are designed,and the corresponding experimental results are shown to explain the geometry effects on the output power of the DMFC.The results indicate that the optimal feature sizes are between 2 and 2.5 mm for both perforated and parallel flow field in the current collectors with an equal open ratio of 50%.This means that for passive methanol fuel cells,to achieve the highest output power,the optimal feature size of the flow field in both anode and cathode current collectors is between 2 and 2.5 mm under the operating mode of this experiment.The effects of rib and channel position are also investigated,and the results indicate that the optimum pattern depends on the feature sizes of the flow field.

Chemical profiling of bioactive compounds in the methanolic extract of wild leaf and callus of Vitex negundo using gas chromatographymass spectrometry

BACKGROUND The investigation of plant-based therapeutic agents in medicinal plants has revealed their presence in the extracts and provides the vision to formulate novel techniques for drug therapy.Vitex negundo(V.negundo),a perennial herb belonging to the Varbanaceae family,is extensively used in conventional medication.AIM To determine the existence of therapeutic components in leaf and callus extracts from wild V.negundo plants using gas chromatography-mass spectrometry(GCMS).METHODS In this study,we conducted GC-MS on wild plant leaf extracts and correlated the presence of constituents with those in callus extracts.Various growth regulators such as 6-benzylaminopurine(BAP),2,4-dichlorophenoxyacetic acid(2,4-D),α-naphthylacetic acid(NAA),and di-phenylurea(DPU)were added to plant leaves and in-vitro callus and grown on MS medium.RESULTS The results clearly indicated that the addition of BAP(2.0 mg/L),2,4-D(0.2 mg/mL),DPU(2.0 mg/L)and 2,4-D(0.2 mg/mL)in MS medium resulted in rapid callus development.The plant profile of Vitex extracts by GC-MS analysis showed that 24,10,and 14 bioactive constituents were detected in the methanolic extract of leaf,green callus and the methanolic extract of white loose callus,respectively.CONCLUSION Octadecadienoic acid,hexadecanoic acid and methyl ester were the major constituents in the leaf and callus methanolic extract.Octadecadienoic acid was the most common constituent in all samples.The maximum concentration of octadecadienoic acid in leaves,green callus and white loose callus was 21.93%,47.79%and 40.38%,respectively.These findings demonstrate that the concentration of octadecadienoic acid doubles in-vitro compared to in-vivo.In addition to octadecadienoic acid;butyric acid,benzene,1-methoxy-4-(1-propenyl),dospan,tridecanedialdehyde,methylcyclohexenylbutanol,chlorpyrifos,n-secondary terpene diester,anflunine and other important active compounds were also detected.All these components were only available in callus formed in-vitro.This study showed that the callus contained additional botanical characteristics compared with wild plants.Due to the presence of numerous bioactive compounds,the medical use of Vitex for various diseases has been accepted and the plant is considered an important source of therapeutics for research and development.

Synthesis of Dimethyl Carbonate from CO_2, Methanol, and Epoxides Using Re(CO)_5Cl/K_2CO_3 as Catalyst System

Over the past few years, dimethyl carbonate （DMC） has been proven to be an efficient methylating, methoxylating, and methoxycarbonylating agent in organic syntheses, in which DMC is used to replace the toxic methyl halides, dimethyl sulfate or carbon monoxide, and so forth. Furthermore, DMC has been used in the syntheses of polycarbonates and polyurethane to develop the nonphosgene routes Therefore, DMC has become one of the most important compounds in the development of green synthetic chemistry.

Temperature and Pressure Behaviours of Methanol, Acetonitrile/Water Mixtures on Chromatographic Systems

Temperature and pressure were shown to vary significantly with solvent mixing, showing maxima at differ-ent solvent ratios. Acetonitrile/water mixing resulted in temperature reduction of solutions whereas metha-nol/water mixing caused temperature increases. On the other hand, maximum recorded chromatographic pressure of acetonitrile:water mixtures occurred at a solvent ratio of 1:6 compared with methanol:water, which showed a maximum pressure at a solvent ratio of 1:1. These findings can be of use in stabilizing re-tention time shifts during HPLC-based studies associated with compound identification based on retention time such as analysis of complex mixtures.

Engineering Cu^(+)/CeZrO_(x) interfaces to promote CO_(2) hydrogenation to methanol

Cu-based catalysts are widely employed for CO_(2) hydrogenation to methanol,which is expected as a promising process to achieving carbon neutrality.However,most Cu-based catalysts still suffer from low methanol yield with a passable CO_(2) conversion and lack insight into its reaction mechanism for guiding the design of catalysts.In this work,Cu^(+)/CeZrO_(x) interfaces are engineered by employing a series of ceria-zirconia solid solution catalysts with various Ce/Zr ratios,forming a Cu^(+)-O_(v)-Ce^(3+)structure where Cu^(+)atoms are bonded to the oxygen vacancies(O_(v))of ceria.Compared to Cu/CeO_(2) and Cu/ZrO_(2),the optimized catalyst(i.e.,Cu_(0.3)Ce_(0.3)Zr_(0.7))exhibits a much higher mass-specific methanol formation rate(192g_(MeOH)/kg_(cat)/h)at 240℃and 3 MPa.Through a series of in-situ and ex-situ characterization,it is revealed that oxygen vacancies in solid solutions can effectively assist the activation of CO_(2) and tune the electronic state of copper to promote the formation of Cu^(+)/CeZrO_(x) interfaces,which stabilizes the key*CO intermediate,inhibits its desorption and facilitates its further hydrogenation to methanol via the reverse watergas-shift(RWGS)+CO-Hydro pathway.Therefore,the concentration of*CO or the apparent Cu^(+)/(Cu^(+)+Cu^(0))ratio could be employed as a quantitative descriptor of the methanol formation rate.This work is expected to give a deep insight into the mechanism of metal/support interfaces in CO_(2) hydrogenation to methanol,offering an effective strategy to develop new catalysts with high performance.

STUDIES ON VAPOR-LIQUID AND LIQUID-LIQUIDVAPOR EQUILIBRIA FOR THE TERNARY SYSTEM METHANOL-METHYL METHACRYLATEWATER (Ⅱ) TERNARY SYSTEM

Isothermal P-x data for homogeneous, and P-x’-x" data for partially miscible mixtures for the ternary system methanol-methyl methacrylate-water have been determined at 25, 35, 45, 55 and 60℃. By using a modified UNIQUAC model and binary parameters only, the predicted ternary phase equilibrium data were found to be in good agreement with the experimental results, indicating the adequacy of using binary model parameters in computing vapor-liquid and liquid-liquid-vapor equilibria covering pressures ranging from reduced to atmospheric.

STUDIES ON VAPOR-LIQUID AND LIQUID-LIQUID-VAPOR EQUILIBRIA FOR THE TERNARY SYSTEM METHANOL-METHYL METHACRYLATEWATER (Ⅰ) THREE BINARY SYSTEMS

Isothermal P-x data tor the binary systems methanol-methyl methacrylate and methanol-water, and isothermal P-x’-x" data for the binary system methyl methacrylate-water have been determined at 25, 35, 45, 55 and 60℃. Based on the maximum likelihood principle, the modified UNIQUAC model pa rameters for these binary systems were obtained by fitting the experimental data. Vapor compositions were then calculated, and the results were compared with literature data.

The effects of methanol extract of cleistopholis patens on the reproductive system of female Wistar rats

Objective:In Port Harcourt and its environs,extracts of Cleistopholis patens are used by traditional medicine healers for the treatment of menstrual irregularities and other gynaecological disorders.The objective of this study was therefore to determine the effects of orally administered methanol extract of the stem bark of Cleistopholis patens on the reproductive organs of non-pregnant albino(Wistar) rats.Methods:3g/kg(low dose) and 6g/kg(high dose) of the extract were administered orally,daily to two different groups of animals,respectively, over a period of 28 days.A third(control) group of animals received distilled water only,orally over the same period.Five animals from each of the groups were sacrificed on day 8,15 and 29.Venous blood samples and reproductive organs respectively were taken from each group of sacrificed animals for hormonal and histopathological analysis.Results:Results of the hormonal assay revealed a general increase in the levels of Follicle Stimulating Hormone(FSH),Luteinizing Hormone(LH),progesterone,and estrogen.The highest levels were noticed in the animals sacrificed on the 29th day(LH =5.48±0.04 IU/L;FSH =3.80±0.00 IU/ L;Progesterone =7.14±0.15 nmol/L;Estrogen = 0.168±0.002 nmol/L).These increases were statistically significant compared to those of the control animals(LH =2.90±0.00 IU /L;FSH = 1.28±0.02 IU/L; Progesterone = 3.80±0.00 nmol/L;Estrogen = 0.130±0.002 nmol/L;P【0.05),and were also dose dependent. Results of the histopathological studies showed presence of chronic inflammatory cells in the tissues of the fallopian tubes and uterus on the 29th day.However,no changes were observed in the ovaries.Conclusion: The administration of the extract produced a dose and time-dependent increase in FSH,LH,progesterone and estrogen levels.We postulate that these observed effects may have been induced by the phytoestrogens (known to have 1/1 000 th of the efficacy of natural oestrogens) in the extract.The hormonal and histopathological changes may explain the effects described by patients following ingestion of extracts of this plant in traditional medical practice.However,it remains to be determined if these effects are harmful or beneficial in disease conditions.

The Vapor－Liquid Equilibrium of the Quaternary Reactive System Methyl acetate－Methanol－Water－Acetic Acid

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Predication of Atmospheric VLE for the Ternary System Dimethyl Carbonate-Methanol-Furfural by Using the Wilson Equation

The vapor-liquid equilibrium of Dimethyl Carbonate-Methanol-Furfural under atmospheric pressure from DMC-CH 3OH,DMCC 5H 4O 2,CH 3OH-C 5H 4O 2 binary systematic VLE data is calculated,by using C ++(VC6.0) programming language and Wilson equation.It provided important VLE data to set up mathematic models of extraction-rectifying separation of DMC and methanol by using furfural as extraction reagent.So the results can be used for chemical engineering calculation.