Glycerol carbonate,an important glycerol value-added product,has been widely used as an active intermediate and inert solvent in the synthesis of cosmetics,detergents,chemical intermediates,polymers,and so on.The dire...Glycerol carbonate,an important glycerol value-added product,has been widely used as an active intermediate and inert solvent in the synthesis of cosmetics,detergents,chemical intermediates,polymers,and so on.The direct carbonylation from glycerol with CO_(2)is considered a promising route,but still tough work due to the thermodynamic stability and the kinetic inertness of CO_(2).In this work,highlyselective direct carbonylation of glycerol and CO_(2)into glycerol carbonate has been achieved over highly dispersed MgInCe-mixed metal oxides(MgInCe-MMO),which were prepared through the topological transformation derived from the MgInCe-layered double hydroxides(MgInCe-LDHs).By precisely modulating the surface basic-acidic properties and the oxygen vacancies,an efficient carbonylation of glycerol with CO_(2)has been achieved with a selectivity of up to>99%to glycerol carbonate.Deep investigation into the synergistic catalysis of base-acid sites and oxygen vacancies has been clarified.展开更多
Microreactors are increasingly used for green and safe chemical processes owing to their benefits of superior mass and heat transfer,increased yield,safety,and simplicity of control.However,immobilizing catalysts in m...Microreactors are increasingly used for green and safe chemical processes owing to their benefits of superior mass and heat transfer,increased yield,safety,and simplicity of control.However,immobilizing catalysts in microreactors remains challenging.In this investigation,a technique for creating Cu_(2)O/montmorillonite catalyst coating,using electrostatic attraction for layer-by-layer self-assembly,was proposed.The montmorillonite film's morphology and thickness could be efficiently regulated by adjusting the degree of exfoliation and surface charge of montmorillonite,alongside layer-by-layer coating times.The Cu_(2)O nanoparticles were immobilized using the flow deposition approach.The resulting Cu_(2)O@montmorillonite-film-coated capillary microreactor successfully transformed glycerol into dihydroxyacetone.The conversion of glycerol and product selectivity could be controlled by adjusting the molar ratio of reactants,temperature,residence time,and Cu_(2)O loading.The maximum glycerol conversion observed was 47.6%,with a 27%selectivity toward dihydroxyacetone.The study presents a technique for immobilizing montmorillonite-based catalyst coatings in capillary tubing,which can serve as a foundation for the future application of microreactors in glycerol conversion.展开更多
Glycerol monolaurate(GML)is a widely used industrial chemical with excellent emulsification and antibacterial effect.The direct esterification of glycerol with lauric acid is the main method to synthesize GML.In this ...Glycerol monolaurate(GML)is a widely used industrial chemical with excellent emulsification and antibacterial effect.The direct esterification of glycerol with lauric acid is the main method to synthesize GML.In this work,the kinetic process of direct esterification was systematically studied using p-toluenesulfonic acid as catalyst.A complete kinetic model of consecutive esterification reaction has been established,and the kinetic equation of acid catalysis was deduced.The isomerization reactions of GML and glycerol dilaurate were investigated.It was found that the reaction was an equilibrium reaction and the reaction rate was faster than the esterification reaction.The kinetic equations of the consecutive esterification reaction were obtained by experiments as k_(1)=(276+92261Xcat)exp(-37720/RT)and k_(2)=(80+4413Xcat)exp(-32240/RT).The kinetic results are beneficial to the optimization of operating conditions and reactor design in GML production process.展开更多
The selective aqueous-phase glycerol hydrogenolysis is a promising reaction to produce commercially useful 1,3-propanediol(1,3-PDO).The Pt-WOx bifunctional catalyst can catalyse the glycerol hydrogenol-ysis but the ca...The selective aqueous-phase glycerol hydrogenolysis is a promising reaction to produce commercially useful 1,3-propanediol(1,3-PDO).The Pt-WOx bifunctional catalyst can catalyse the glycerol hydrogenol-ysis but the catalyst deactivation via sintering,metal leaching,and coking can predominantly occur in the aqueous phase reaction.In this work,the effect of reaction temperature,pressure and second promoter(Cu,Fe,Rh,Mn,Re,Ru,Ir,Sn,B,and P)on catalytic performance and deactivation behaviour of Pt/WOx/-Al2O3 was investigated.When doped with Rh,Mn,Re,Ru,Ir,B,and P,the second promoter boosts catalytic activity by promoting great dispersion of Pt on support and increasing Pt surface area.The increased Bronsted acid sites lead to selective synthesis of 1,3-PDO than 1,2-propanediol(1,2-PDO).The characterization studies of fresh and spent catalysts reveal that the main cause of catalyst deactivation is the Pt sintering,as interpreted based on XRD,CO chemisorption,and TEM analyses.The Pt sintering is affected depending on the second promoter that can either or reduce the interaction between Pt,WO_(χ)/γ and Al_(2)O_(3).As an electron acceptor of Pt in Pt/WO_(χ)/γ-Al_(2)O_(3),Re and Mn as second promoters resulted in increased Pt^(2+) on the catalytic surface,which strengthens the contact between Pt andγ-Al_(2)O_(3) and WO_(χ),resulting in a decrease in Pt sintering.The metal leaching and coking are not affected by the presence of second promoter.The catalyst modified with a second promoter possesses improved catalytic activity and 1,3-PDO production,however the stability continues to remain a challenge.The present work unrav-elled the determining parameters of catalytic activity and deactivation,thus providing a promising pro-tocol toward effective catalysts for glycerol hydrogenolysis.展开更多
Hydrogen production from electrolytic water is an important sustainable technology to realize renewable energy conversion and carbon neutrality.However,it is limited by the high overpotential of oxygen evolution react...Hydrogen production from electrolytic water is an important sustainable technology to realize renewable energy conversion and carbon neutrality.However,it is limited by the high overpotential of oxygen evolution reaction(OER)at the anode.To reduce the operating voltage of electrolyzer,herein thermodynamically favorable glycerol oxidation reaction(GOR)is proposed to replace the OER.Moreover,vertical Ni O flakes and NiMoNH nanopillars are developed to boost the reaction kinetics of anodic GOR and cathodic hydrogen evolution,respectively.Meanwhile,excluding the explosion risk of mixed H_2/O_(2),a cheap organic membrane is used to replace the expensive anion exchange membrane in the electrolyzer.Impressively,the electrolyzer delivers a remarkable reduction of operation voltage by 280 mV,and exhibits good long-term stability.This work provides a new paradigm of hydrogen production with low cost and good feasibility.展开更多
Glycerol(electrochemical) oxidation reaction(GOR) producing organic small molecule acid and coupling with hydrogen evolution reaction is a critical aspect of ensuring balanced glycerol capacity and promoting hydrogen ...Glycerol(electrochemical) oxidation reaction(GOR) producing organic small molecule acid and coupling with hydrogen evolution reaction is a critical aspect of ensuring balanced glycerol capacity and promoting hydrogen generation on a large scale. However, the development of highly efficient and selective non-noble metal-based GOR electrocatalysts is still a key problem. Here, an S-doped CuO nanorod array catalyst(S-CuO/CF) constructed by sulfur leaching and oxidative remodeling is used to drive GOR at low potentials: It requires potentials of only 1.23 and 1.33 V versus RHE to provide currents of 100 and 500 mA cm^(-2), respectively. Moreover, it shows satisfactory comprehensive performance(at 100 mA cm^(-2), V_(cell) = 1.37 V) when assembled as the anode in asymmetric coupled electrolytic cell. Furthermore, we propose a detailed cycle reaction pathway(in alkaline environment) of S-doped CuO surface promoting GOR to produce formic acid and glycolic acid. Among them, the C–C bond breaking and lattice oxygen deintercalation steps frequently involved in the reaction pathway are the key factors to determine the catalytic performance and product selectivity. This research provides valuable guidance for the development of transition metal-based electrocatalysts for GOR and valuable insights into the glycerol oxidation cycle reaction pathway.展开更多
Selective oxidation of glycerol is a hot topic.Increased biodiesel production has led to glycerol oxidation over Au- and Pt-based catalysts being widely studied.However,Pt catalysts suffer from deactivation because of...Selective oxidation of glycerol is a hot topic.Increased biodiesel production has led to glycerol oxidation over Au- and Pt-based catalysts being widely studied.However,Pt catalysts suffer from deactivation because of weak metal-support interactions.In this study,multi-walled carbon nanotube（MWCNTs）-pillared nitrogen-doped graphene（NG） was prepared by direct pyrolysis of melamine on MWCNTs,and the synthesized NG-MWCNT composite was used as the support for Pt.Characterization results showed that the surface area（173 m^2/g） and pore volume of the NG-MWCNT composite were greater than those of bare MWCNTs and the separated melamine pyrolysis product（CH_x）.Pt（1.4±0.4 nm） dispersion on the NG-MWCNTs was favorable and the Pt/NG-MWCNT catalyst was highly active and selective in the oxidation of glycerol to glyceric acid（GLYA） in base-free aqueous solution.For example,the conversion of glycerol reached 64.4% with a GLYA selectivity of 81.0%,whereas the conversions of glycerol over Pt/MWCNTs and Pt/CN_x were 29.0% and 31.6%,respectively.The unique catalytic activity of the Pt/NG-MWCNTs is attributed to well-dispersed Pt clusters on the NG-MWCNTs and the electron-donating effect of the nitrogen dopant in the NG-MWCNTs.展开更多
Pt/activated carbon （Pt/AC） catalyst combined with base works efficiently for lactic acid production from glycerol under mild conditions. Base type （LiOH, NaOH, KOH, or Ba（OH）2） and base/glycerol molar ratio sig...Pt/activated carbon （Pt/AC） catalyst combined with base works efficiently for lactic acid production from glycerol under mild conditions. Base type （LiOH, NaOH, KOH, or Ba（OH）2） and base/glycerol molar ratio significantly affected the catalytic performance. The corresponding lactic acid selectivity was in the order of LiOH〉NaOH〉KOH〉Ba（OH）2. An increase in LiOH/glycerol molar ratio ele‐vated the glycerol conversion and lactic acid selectivity to some degree, but excess LiOH inhibited the transformation of glycerol to lactic acid. In the presence of Pt/AC catalyst, the maximum selec‐tivity of lactic acid was 69.3% at a glycerol conversion of 100% after 6 h at 90 °C, with a Li‐OH/glycerol molar ratio of 1.5. The Pt/AC catalyst was recycled five times and was found to exhibit slightly decreased glycerol conversion and stable lactic acid selectivity. In addition, the experimental results indicated that reaction intermediate dihydroxyacetone was more favorable as the starting reagent for lactic acid formation than glyceraldehyde. However, the Pt/AC catalyst had adverse effects on the intermediate transformation to lactic acid, because it favored the catalytic oxidation of them to glyceric acid.展开更多
This research was focused on the valorisation of glycerol,exploring the feasibility of an efficient route for oxygenated additives production based on its etherification with bio-butanol.A home-made BEA zeolite sample...This research was focused on the valorisation of glycerol,exploring the feasibility of an efficient route for oxygenated additives production based on its etherification with bio-butanol.A home-made BEA zeolite sample with a tuneable acidity has been proposed as the catalytic system,being tested in a stirred reactor under different etherification conditions.Although a reaction temperature as high as 200℃resulted to be beneficial in terms of glycerol conversion(-90%),only by operating at milder conditions the product selectivity to glycerol-ethers can be better controlled,in order to obtain a bio-fuel complying with the requirements for mixing with fossil diesel or biodiesel,without any need of purification from large amount of by-products.A comprehensive identification of all the compounds formed during the reaction was performed by a GC-MS analysis,on the basis of the complex network of consecutive and parallel reaction paths leading not only to the desired ethers,but also to many side products not detected in similar acid-catalyzed reactions in liquid phase and not available in the most used mass-spectra libraries.展开更多
Purification of original crude glycerol obtained from biodiesel production was conducted in a laboratory scale equipment by means of a combined chemical and physical treatment method based upon repeated cycles of acid...Purification of original crude glycerol obtained from biodiesel production was conducted in a laboratory scale equipment by means of a combined chemical and physical treatment method based upon repeated cycles of acidification of liquid phase to the desired pH value by using 5.85% H3PO4 solution for pH value adjustment, and the mixture was kept at 70 ℃ for 60 rain to make phase separation for obtaining a glycerol-rich middle phase. The yield of crude glycerol reached 81.2%. Subsequently, upon reaction of the obtained glycerol phase with 0.03% of sodium oxalate at 80 ℃ for 30 min the impurity removal rate was equal to 19.8%. The fraction boiling between 164 ℃ and 200 ℃ was collected by vacuum distil- lation followed by decolorization with 2% of active carbon at 80 ℃ for two times to yield the product glycerol with an ac- ceptable purity of 98.10%.展开更多
Bimetallic CoCu nanocomposites were synthesized in polyol by using Ru as heterogeneous nucleation agent and stearic acid as surfactant, and their catalytic properties were investi- gated by hydrogenolysis of glycerol ...Bimetallic CoCu nanocomposites were synthesized in polyol by using Ru as heterogeneous nucleation agent and stearic acid as surfactant, and their catalytic properties were investi- gated by hydrogenolysis of glycerol to propanediols. It was found that the surfactant could induce Co nanocrystals to form nanowires as structure-directing agent, while it＇s ineffective for Cu because only spherical Cu particles were produced under the same condition. When Co2＋ and Cu2＋ coexist in polyol, Cu2＋ is firstly reduced and forms the spherical particles, and then the Cu particles afford surface for the subsequential reduction of Co2＋ and growth of Co nanocrystals to form the nanorods, obtaining the urchin-like CoCu nanocomposites. The catalytic performance in selective hydrogenolysis of glycerol to propanediols proposed that the CoCu urchin-like nanocomposites was superior to the Co nanowires possibly due to that the synergistic effect between Co and Cu component promoted conversion of glyc- erol and obtained the higher propanediol yields based on the specific surface areas of the catalysts.展开更多
The morphologic changes and growth status of PC12 cells were observed after intervened by different concentrations of methanol, ethanol, acetone, glycerol and the toxic concentrations were ascertained. Four kinds of o...The morphologic changes and growth status of PC12 cells were observed after intervened by different concentrations of methanol, ethanol, acetone, glycerol and the toxic concentrations were ascertained. Four kinds of organic solvents al showed certain cytotoxicity to PC12 cells. Compared with other three kinds of or-ganic solvents, ethanol showed the most obvious cytotoxicity to PC12 cells and the cellviability would be reduced to 60% if the concentration of ethanol was 20 ml/L and the intervention lasted for 24 h. Under the same condition, the reduced per-centages of cellviability for acetone and ethanol were 20% and 15% respectively. Glycerol also showed cytotoxicity to PC12 cells, especial y as the concentration was raised gradual y, but the toxicity was relatively mild. This study would provide refer-ence material for subsequent pharmacological studies.展开更多
The biodiesel production technology catalyzed by 1,8-diazabicycloundec-7-ene（DBU）is developed in this work.Crude glycerol containing DBU and DBU/glycerol/CO2（DGC）ionic compounds reacts directly with dimethyl carbo...The biodiesel production technology catalyzed by 1,8-diazabicycloundec-7-ene（DBU）is developed in this work.Crude glycerol containing DBU and DBU/glycerol/CO2（DGC）ionic compounds reacts directly with dimethyl carbonate（DMC）to produce high value-added glycerol carbonate（GC）catalyzed by DBU and DGC.The catalytic performance of DBU and DGC,as well as the kinetics of the reaction catalyzed by DBU,were investigated.The results show that DGC has a weak catalytic effect on the transesterification of glycerol and DMC.When the temperature is higher than 60℃,DGC catalyzes the reaction jointly with DBU,which is produced from the decomposition of DGC.DBU has a good catalytic effect on the reaction between glycerol and DMC,with 90%conversion of glycerol and 84%selectivity to GC under the following conditions：DMC-to-glycerol molar ratio of 3：1,4.0%DBU（based on glycerol mass）,reaction time of 60 min,and reaction temperature of 40℃.The apparent kinetics results show that the activation energies are 30.95 kJ·mol^-1 and 55.16 kJ·mol^-1 for the forward and reverse GC generation reactions,respectively,and the activation energy of the decomposition reaction of GC to glycidol（GD）is 26.58 kJ·mol^-1.展开更多
The surface of SiO2 support was pretreated by C1-C4 normal alcohols before the impregnation of iridium and rhenium precursors.These catalysts were applied in high concentration glycerol aqueous solution hydrogenolysis...The surface of SiO2 support was pretreated by C1-C4 normal alcohols before the impregnation of iridium and rhenium precursors.These catalysts were applied in high concentration glycerol aqueous solution hydrogenolysis.The catalysts prepared from the pretreated supports exhibited high catalytic activity because of the formation of more active sites from a high dispersion of iridium oxide and rhenium oxide.The catalysts with the support pretreated by 1-propanol showed the highest glycerol conversion of 59.5%.The supports and catalysts were characterized by FT-IR,nitrogen adsorption,TPR,XRD,TEM,H2-chemisorption and NH3-TPD.展开更多
Rhodium nanoparticle-loaded carbon black (Rh/CB) was prepared by a wet method, and its activity and durability for glycerol oxidation reaction (GOR) in alkaline medium were compared with Pt, Pd and Au nanoparticle-loa...Rhodium nanoparticle-loaded carbon black (Rh/CB) was prepared by a wet method, and its activity and durability for glycerol oxidation reaction (GOR) in alkaline medium were compared with Pt, Pd and Au nanoparticle-loaded CB (Pt/CB, Pd/CB and Au/CB). In the cyclic voltammogram of the Rh/CB electrode, the redox waves due to hydrogen adsorption/desorption and the surface OH monolayer formation/reduction were observed at more negative potentials than the Pt/CB and Pd/CB electrodes. The onset and peak potentials of the GOR current densities for the Rh/CB electrode were ca. –0.55 and –0.30 V vs. Hg/HgO, respectively, which were 0.10 and 0.20 V more negative than the Pt/CB electrode whose GOR activity was the best, indicating that Rh was a fascinating metal for reducing the overpotential for GOR. In the electrostatic electrolysis with the Rh/CB and Pt/CB electrodes, the decrease in the GOR current density in the former with time was suppressed compared to that in the latter, suggesting that the tolerance to poisoning for the Rh/CB electrode was superior to that for the Pt/CB electrode.展开更多
To improve the activity for glycerol oxidation reaction (GOR) of Pt, PtAg (mole ratio of Pt/Ag = 3 and 1) alloy nanoparticle-loaded carbon black (Pt/CB, PtAg(3:1)/CB, PtAg(1:1)/CB) catalysts were prepared by a wet met...To improve the activity for glycerol oxidation reaction (GOR) of Pt, PtAg (mole ratio of Pt/Ag = 3 and 1) alloy nanoparticle-loaded carbon black (Pt/CB, PtAg(3:1)/CB, PtAg(1:1)/CB) catalysts were prepared by a wet method. The resultant catalysts, moreover, were heat-treated in a N2 atmosphere at 200°C. The alloying of Pt with Ag for each PtAg/CB was confirmed by X-ray diffractometry and electron dispersive X-ray spectrometry. The heat-treatment did not change the crystal structure of the PtAg alloys and increased their particle size. X-ray photoelectron spectroscopy exhibited that stabilizers were completely removed from the PtAg alloy surface, and the Pt4f and Ag3d doublets due to metallic Pt and Ag, respectively, shifted to lower binding energies, supporting the alloying of Pt with Ag. Both PtAg/CB electrodes had two oxidation waves of glycerol irrespective of heat-treatment, which was different from the Pt/CB electrode. The onset potential of the first oxidation wave was -0.60 V, which was 0.20 V less positive than that for the Pt/CB electrode, indicating the alloying of Pt with Ag greatly improved the GOR activity of Pt. The heat-treated PtAg(3:1)/ CB electrode improved the GOR current density of the second oxidation peak. In the potentiostatic electrolysis at -0.1 and 0 V for both PtAg/CB electrodes, the ratio of oxidation current density at 60 min to that at 5 min (j<sub>60</sub>/j<sub>5</sub>), an indicator of the catalyst deterioration, at 0 V was higher than that at -0.1 V, because the adsorbed oxidation intermediates were greatly consumed at the larger overpotential. The heat-treatment of the PtAg(3:1)/CB electrode increased the j60</sub>/j5</sub> value at -0.1 V but decreased that at 0 V. This could be attributed to the formation of high-order oxidation intermediates which might have stronger poisoning effect.展开更多
Techno-economic analysis of an indirect use of carbon dioxide within the route of glycerolysis of glycerol with urea is investigated. The results show that the net present value of the biodiesel-glycerol carbonate pro...Techno-economic analysis of an indirect use of carbon dioxide within the route of glycerolysis of glycerol with urea is investigated. The results show that the net present value of the biodiesel-glycerol carbonate production by glycerolysis is higher than the biodiesel-glycerol carbonate production by direct carboxylationat at the end of the 12-year operation with similar capacities. The stochastic model has predicted that using glycerolysis route for the synthesis of glycerol carbonate production might increase the probability of getting positive net present value by about 15%.展开更多
It is of importance to convert glycerol,the primary by-product from biodiesel manufacturing,to various valuable C3 chemicals,such as acrolein via dehydration,lactic acid,1,3-dihydroxyacetone via oxidation,and 1,3-prop...It is of importance to convert glycerol,the primary by-product from biodiesel manufacturing,to various valuable C3 chemicals,such as acrolein via dehydration,lactic acid,1,3-dihydroxyacetone via oxidation,and 1,3-propanediol,allyl alcohol via hydrogenolysis.As compared to petroleum-based resources,C3 chemicals from glycerol provide a benign,sustainable and atomically economic feature.Extensive heterogeneous catalysts have been designed,prepared and tested for these transformations.In recent five years,great progress,including high yields to target products over appropriate catalysts,insight into reaction mechanism and network,has been achieved.The present review systematically covers recent research progress on sustainable C3 chemical production from catalytic glycerol transformations.We hope that it will benefit future research on transformations of glycerol as well as other polyols.展开更多
Catalytic transformation of cellulose into value-added chemicals is of great importance for utilization of renewable and abundant biomass. Due to the high oxygen content, cellulose serves as an ideal candidate for the...Catalytic transformation of cellulose into value-added chemicals is of great importance for utilization of renewable and abundant biomass. Due to the high oxygen content, cellulose serves as an ideal candidate for the production of oxygenates, in particular lactic acid which is a versatile building block in chemical industry. The efficient conversion of cellulose to lactic acid generally requires selective activation of specific C-O and C-C bonds, and therefore multifunctional catalysts that combine several key reactions including hydrolysis, isomerization and retro-aldol fragmentation are highly desirable. This review article highlights the recently developed catalytic systems and catalysts for the selective transformation of cellulose and cellulose-derived carbohydrates into lactic acid, lactates and/or its esters. Emphases will be put on the reaction mechanism and key factors that exert effects on the catalytic performances. In addition, the catalytic transformation of glycerol, a C3 compound over-supplied from biodiesel industry, will also be surveyed. Recent advances in the development of new catalysts or strategies are analyzed and discussed to gain insight into the transformation of C3 compound to lactic acid.展开更多
The selective hydrogenolysis of glycerol to 1,3-propanediol(1,3-PDO)is an attractive reaction due to the high demand for valorization of huge excess amounts of glycerol supply as well as the important application of 1...The selective hydrogenolysis of glycerol to 1,3-propanediol(1,3-PDO)is an attractive reaction due to the high demand for valorization of huge excess amounts of glycerol supply as well as the important application of 1,3-PDO in polyester industry.Nevertheless,the formation of 1,3-PDO is thermodynamically less favorable than 1,2-PDO,which necessitates the development of efficient catalysts to manipulate the reaction kinetics towards the 1,3-PDO formation.Among others,Pt-W based catalysts have shown promising activities and selectivities of 1,3-PDO although the reaction mechanism is not well addressed at the molecular level.In this short review,we have compared the performances of different Pt-W based catalysts and discussed the key factors influencing the activity and selectivity.Three possible reaction mechanisms have been discussed in terms of the synergy between Pt and WO_x and the origin of acid sites.Finally,the long-term stability of the Pt-W catalysts has been discussed.We hope this review will provide useful information for the development of more efficient catalysts for this important reaction.展开更多
基金Financial support from the National Key Research and Development Program of China(2022YFB3805602)the National Natural Science Foundation of China(22138001,22288102)the Fundamental Research Funds for the Central Universities。
文摘Glycerol carbonate,an important glycerol value-added product,has been widely used as an active intermediate and inert solvent in the synthesis of cosmetics,detergents,chemical intermediates,polymers,and so on.The direct carbonylation from glycerol with CO_(2)is considered a promising route,but still tough work due to the thermodynamic stability and the kinetic inertness of CO_(2).In this work,highlyselective direct carbonylation of glycerol and CO_(2)into glycerol carbonate has been achieved over highly dispersed MgInCe-mixed metal oxides(MgInCe-MMO),which were prepared through the topological transformation derived from the MgInCe-layered double hydroxides(MgInCe-LDHs).By precisely modulating the surface basic-acidic properties and the oxygen vacancies,an efficient carbonylation of glycerol with CO_(2)has been achieved with a selectivity of up to>99%to glycerol carbonate.Deep investigation into the synergistic catalysis of base-acid sites and oxygen vacancies has been clarified.
基金support from the National Natural Science Foundation of China(2207213641672033)+2 种基金the research grants from Engineering Research Center of Non-metallic Minerals of Zhejiang Province(ZD2023K01)the projects from Qing Yang Institute for Industrial Minerals(KYYHX-20220336KYY-HX-20170557).
文摘Microreactors are increasingly used for green and safe chemical processes owing to their benefits of superior mass and heat transfer,increased yield,safety,and simplicity of control.However,immobilizing catalysts in microreactors remains challenging.In this investigation,a technique for creating Cu_(2)O/montmorillonite catalyst coating,using electrostatic attraction for layer-by-layer self-assembly,was proposed.The montmorillonite film's morphology and thickness could be efficiently regulated by adjusting the degree of exfoliation and surface charge of montmorillonite,alongside layer-by-layer coating times.The Cu_(2)O nanoparticles were immobilized using the flow deposition approach.The resulting Cu_(2)O@montmorillonite-film-coated capillary microreactor successfully transformed glycerol into dihydroxyacetone.The conversion of glycerol and product selectivity could be controlled by adjusting the molar ratio of reactants,temperature,residence time,and Cu_(2)O loading.The maximum glycerol conversion observed was 47.6%,with a 27%selectivity toward dihydroxyacetone.The study presents a technique for immobilizing montmorillonite-based catalyst coatings in capillary tubing,which can serve as a foundation for the future application of microreactors in glycerol conversion.
基金supported by the National Research and Development Program of China(2021YFC3001100)the National Natural Science Foundation of China(22288102).
文摘Glycerol monolaurate(GML)is a widely used industrial chemical with excellent emulsification and antibacterial effect.The direct esterification of glycerol with lauric acid is the main method to synthesize GML.In this work,the kinetic process of direct esterification was systematically studied using p-toluenesulfonic acid as catalyst.A complete kinetic model of consecutive esterification reaction has been established,and the kinetic equation of acid catalysis was deduced.The isomerization reactions of GML and glycerol dilaurate were investigated.It was found that the reaction was an equilibrium reaction and the reaction rate was faster than the esterification reaction.The kinetic equations of the consecutive esterification reaction were obtained by experiments as k_(1)=(276+92261Xcat)exp(-37720/RT)and k_(2)=(80+4413Xcat)exp(-32240/RT).The kinetic results are beneficial to the optimization of operating conditions and reactor design in GML production process.
基金funded by the National Research Council of Thailand (NRCT)the Second Century Foundation (C2F),Chulalongkorn University,ThailandResearcher Supporting Project RSP2024RR400,King Saud University,Saudi Arabia
文摘The selective aqueous-phase glycerol hydrogenolysis is a promising reaction to produce commercially useful 1,3-propanediol(1,3-PDO).The Pt-WOx bifunctional catalyst can catalyse the glycerol hydrogenol-ysis but the catalyst deactivation via sintering,metal leaching,and coking can predominantly occur in the aqueous phase reaction.In this work,the effect of reaction temperature,pressure and second promoter(Cu,Fe,Rh,Mn,Re,Ru,Ir,Sn,B,and P)on catalytic performance and deactivation behaviour of Pt/WOx/-Al2O3 was investigated.When doped with Rh,Mn,Re,Ru,Ir,B,and P,the second promoter boosts catalytic activity by promoting great dispersion of Pt on support and increasing Pt surface area.The increased Bronsted acid sites lead to selective synthesis of 1,3-PDO than 1,2-propanediol(1,2-PDO).The characterization studies of fresh and spent catalysts reveal that the main cause of catalyst deactivation is the Pt sintering,as interpreted based on XRD,CO chemisorption,and TEM analyses.The Pt sintering is affected depending on the second promoter that can either or reduce the interaction between Pt,WO_(χ)/γ and Al_(2)O_(3).As an electron acceptor of Pt in Pt/WO_(χ)/γ-Al_(2)O_(3),Re and Mn as second promoters resulted in increased Pt^(2+) on the catalytic surface,which strengthens the contact between Pt andγ-Al_(2)O_(3) and WO_(χ),resulting in a decrease in Pt sintering.The metal leaching and coking are not affected by the presence of second promoter.The catalyst modified with a second promoter possesses improved catalytic activity and 1,3-PDO production,however the stability continues to remain a challenge.The present work unrav-elled the determining parameters of catalytic activity and deactivation,thus providing a promising pro-tocol toward effective catalysts for glycerol hydrogenolysis.
基金the financial support from National Natural Science Foundation of China(92163117,52072389,52172058,51972006)。
文摘Hydrogen production from electrolytic water is an important sustainable technology to realize renewable energy conversion and carbon neutrality.However,it is limited by the high overpotential of oxygen evolution reaction(OER)at the anode.To reduce the operating voltage of electrolyzer,herein thermodynamically favorable glycerol oxidation reaction(GOR)is proposed to replace the OER.Moreover,vertical Ni O flakes and NiMoNH nanopillars are developed to boost the reaction kinetics of anodic GOR and cathodic hydrogen evolution,respectively.Meanwhile,excluding the explosion risk of mixed H_2/O_(2),a cheap organic membrane is used to replace the expensive anion exchange membrane in the electrolyzer.Impressively,the electrolyzer delivers a remarkable reduction of operation voltage by 280 mV,and exhibits good long-term stability.This work provides a new paradigm of hydrogen production with low cost and good feasibility.
基金financially supported by National Natural Science Foundation of China (52174283 and 52274308)。
文摘Glycerol(electrochemical) oxidation reaction(GOR) producing organic small molecule acid and coupling with hydrogen evolution reaction is a critical aspect of ensuring balanced glycerol capacity and promoting hydrogen generation on a large scale. However, the development of highly efficient and selective non-noble metal-based GOR electrocatalysts is still a key problem. Here, an S-doped CuO nanorod array catalyst(S-CuO/CF) constructed by sulfur leaching and oxidative remodeling is used to drive GOR at low potentials: It requires potentials of only 1.23 and 1.33 V versus RHE to provide currents of 100 and 500 mA cm^(-2), respectively. Moreover, it shows satisfactory comprehensive performance(at 100 mA cm^(-2), V_(cell) = 1.37 V) when assembled as the anode in asymmetric coupled electrolytic cell. Furthermore, we propose a detailed cycle reaction pathway(in alkaline environment) of S-doped CuO surface promoting GOR to produce formic acid and glycolic acid. Among them, the C–C bond breaking and lattice oxygen deintercalation steps frequently involved in the reaction pathway are the key factors to determine the catalytic performance and product selectivity. This research provides valuable guidance for the development of transition metal-based electrocatalysts for GOR and valuable insights into the glycerol oxidation cycle reaction pathway.
基金financially supported by the National Natural Science Foundation of China(21473155,21273198,21073159)Natural Science Foundation of Zhejiang Province(L12B03001)the foundation from State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology(GCTKF2014009)~~
文摘Selective oxidation of glycerol is a hot topic.Increased biodiesel production has led to glycerol oxidation over Au- and Pt-based catalysts being widely studied.However,Pt catalysts suffer from deactivation because of weak metal-support interactions.In this study,multi-walled carbon nanotube（MWCNTs）-pillared nitrogen-doped graphene（NG） was prepared by direct pyrolysis of melamine on MWCNTs,and the synthesized NG-MWCNT composite was used as the support for Pt.Characterization results showed that the surface area（173 m^2/g） and pore volume of the NG-MWCNT composite were greater than those of bare MWCNTs and the separated melamine pyrolysis product（CH_x）.Pt（1.4±0.4 nm） dispersion on the NG-MWCNTs was favorable and the Pt/NG-MWCNT catalyst was highly active and selective in the oxidation of glycerol to glyceric acid（GLYA） in base-free aqueous solution.For example,the conversion of glycerol reached 64.4% with a GLYA selectivity of 81.0%,whereas the conversions of glycerol over Pt/MWCNTs and Pt/CN_x were 29.0% and 31.6%,respectively.The unique catalytic activity of the Pt/NG-MWCNTs is attributed to well-dispersed Pt clusters on the NG-MWCNTs and the electron-donating effect of the nitrogen dopant in the NG-MWCNTs.
基金supported by the National Natural Science Foundation of China(21176236)~~
文摘Pt/activated carbon （Pt/AC） catalyst combined with base works efficiently for lactic acid production from glycerol under mild conditions. Base type （LiOH, NaOH, KOH, or Ba（OH）2） and base/glycerol molar ratio significantly affected the catalytic performance. The corresponding lactic acid selectivity was in the order of LiOH〉NaOH〉KOH〉Ba（OH）2. An increase in LiOH/glycerol molar ratio ele‐vated the glycerol conversion and lactic acid selectivity to some degree, but excess LiOH inhibited the transformation of glycerol to lactic acid. In the presence of Pt/AC catalyst, the maximum selec‐tivity of lactic acid was 69.3% at a glycerol conversion of 100% after 6 h at 90 °C, with a Li‐OH/glycerol molar ratio of 1.5. The Pt/AC catalyst was recycled five times and was found to exhibit slightly decreased glycerol conversion and stable lactic acid selectivity. In addition, the experimental results indicated that reaction intermediate dihydroxyacetone was more favorable as the starting reagent for lactic acid formation than glyceraldehyde. However, the Pt/AC catalyst had adverse effects on the intermediate transformation to lactic acid, because it favored the catalytic oxidation of them to glyceric acid.
文摘This research was focused on the valorisation of glycerol,exploring the feasibility of an efficient route for oxygenated additives production based on its etherification with bio-butanol.A home-made BEA zeolite sample with a tuneable acidity has been proposed as the catalytic system,being tested in a stirred reactor under different etherification conditions.Although a reaction temperature as high as 200℃resulted to be beneficial in terms of glycerol conversion(-90%),only by operating at milder conditions the product selectivity to glycerol-ethers can be better controlled,in order to obtain a bio-fuel complying with the requirements for mixing with fossil diesel or biodiesel,without any need of purification from large amount of by-products.A comprehensive identification of all the compounds formed during the reaction was performed by a GC-MS analysis,on the basis of the complex network of consecutive and parallel reaction paths leading not only to the desired ethers,but also to many side products not detected in similar acid-catalyzed reactions in liquid phase and not available in the most used mass-spectra libraries.
基金the financial support from Scientific Research Foundation for Doctoral Program of Liaoning Province(20081104)
文摘Purification of original crude glycerol obtained from biodiesel production was conducted in a laboratory scale equipment by means of a combined chemical and physical treatment method based upon repeated cycles of acidification of liquid phase to the desired pH value by using 5.85% H3PO4 solution for pH value adjustment, and the mixture was kept at 70 ℃ for 60 rain to make phase separation for obtaining a glycerol-rich middle phase. The yield of crude glycerol reached 81.2%. Subsequently, upon reaction of the obtained glycerol phase with 0.03% of sodium oxalate at 80 ℃ for 30 min the impurity removal rate was equal to 19.8%. The fraction boiling between 164 ℃ and 200 ℃ was collected by vacuum distil- lation followed by decolorization with 2% of active carbon at 80 ℃ for two times to yield the product glycerol with an ac- ceptable purity of 98.10%.
基金This work was supported by the National Ba- sic Research Program of China （No.2012CB215304）, tile Science Foundation of Guangdong Province （No.$2012040006992）, and the International Co- operation Project of Ministry of Science and Technology of China （No.2012DFA61080）.
文摘Bimetallic CoCu nanocomposites were synthesized in polyol by using Ru as heterogeneous nucleation agent and stearic acid as surfactant, and their catalytic properties were investi- gated by hydrogenolysis of glycerol to propanediols. It was found that the surfactant could induce Co nanocrystals to form nanowires as structure-directing agent, while it＇s ineffective for Cu because only spherical Cu particles were produced under the same condition. When Co2＋ and Cu2＋ coexist in polyol, Cu2＋ is firstly reduced and forms the spherical particles, and then the Cu particles afford surface for the subsequential reduction of Co2＋ and growth of Co nanocrystals to form the nanorods, obtaining the urchin-like CoCu nanocomposites. The catalytic performance in selective hydrogenolysis of glycerol to propanediols proposed that the CoCu urchin-like nanocomposites was superior to the Co nanowires possibly due to that the synergistic effect between Co and Cu component promoted conversion of glyc- erol and obtained the higher propanediol yields based on the specific surface areas of the catalysts.
文摘The morphologic changes and growth status of PC12 cells were observed after intervened by different concentrations of methanol, ethanol, acetone, glycerol and the toxic concentrations were ascertained. Four kinds of organic solvents al showed certain cytotoxicity to PC12 cells. Compared with other three kinds of or-ganic solvents, ethanol showed the most obvious cytotoxicity to PC12 cells and the cellviability would be reduced to 60% if the concentration of ethanol was 20 ml/L and the intervention lasted for 24 h. Under the same condition, the reduced per-centages of cellviability for acetone and ethanol were 20% and 15% respectively. Glycerol also showed cytotoxicity to PC12 cells, especial y as the concentration was raised gradual y, but the toxicity was relatively mild. This study would provide refer-ence material for subsequent pharmacological studies.
基金Supported by the National Natural Science Foundation of China(No.21476150)
文摘The biodiesel production technology catalyzed by 1,8-diazabicycloundec-7-ene（DBU）is developed in this work.Crude glycerol containing DBU and DBU/glycerol/CO2（DGC）ionic compounds reacts directly with dimethyl carbonate（DMC）to produce high value-added glycerol carbonate（GC）catalyzed by DBU and DGC.The catalytic performance of DBU and DGC,as well as the kinetics of the reaction catalyzed by DBU,were investigated.The results show that DGC has a weak catalytic effect on the transesterification of glycerol and DMC.When the temperature is higher than 60℃,DGC catalyzes the reaction jointly with DBU,which is produced from the decomposition of DGC.DBU has a good catalytic effect on the reaction between glycerol and DMC,with 90%conversion of glycerol and 84%selectivity to GC under the following conditions：DMC-to-glycerol molar ratio of 3：1,4.0%DBU（based on glycerol mass）,reaction time of 60 min,and reaction temperature of 40℃.The apparent kinetics results show that the activation energies are 30.95 kJ·mol^-1 and 55.16 kJ·mol^-1 for the forward and reverse GC generation reactions,respectively,and the activation energy of the decomposition reaction of GC to glycidol（GD）is 26.58 kJ·mol^-1.
基金supported by the National Natural Science Foundation of China(21403217)~~
文摘The surface of SiO2 support was pretreated by C1-C4 normal alcohols before the impregnation of iridium and rhenium precursors.These catalysts were applied in high concentration glycerol aqueous solution hydrogenolysis.The catalysts prepared from the pretreated supports exhibited high catalytic activity because of the formation of more active sites from a high dispersion of iridium oxide and rhenium oxide.The catalysts with the support pretreated by 1-propanol showed the highest glycerol conversion of 59.5%.The supports and catalysts were characterized by FT-IR,nitrogen adsorption,TPR,XRD,TEM,H2-chemisorption and NH3-TPD.
文摘Rhodium nanoparticle-loaded carbon black (Rh/CB) was prepared by a wet method, and its activity and durability for glycerol oxidation reaction (GOR) in alkaline medium were compared with Pt, Pd and Au nanoparticle-loaded CB (Pt/CB, Pd/CB and Au/CB). In the cyclic voltammogram of the Rh/CB electrode, the redox waves due to hydrogen adsorption/desorption and the surface OH monolayer formation/reduction were observed at more negative potentials than the Pt/CB and Pd/CB electrodes. The onset and peak potentials of the GOR current densities for the Rh/CB electrode were ca. –0.55 and –0.30 V vs. Hg/HgO, respectively, which were 0.10 and 0.20 V more negative than the Pt/CB electrode whose GOR activity was the best, indicating that Rh was a fascinating metal for reducing the overpotential for GOR. In the electrostatic electrolysis with the Rh/CB and Pt/CB electrodes, the decrease in the GOR current density in the former with time was suppressed compared to that in the latter, suggesting that the tolerance to poisoning for the Rh/CB electrode was superior to that for the Pt/CB electrode.
文摘To improve the activity for glycerol oxidation reaction (GOR) of Pt, PtAg (mole ratio of Pt/Ag = 3 and 1) alloy nanoparticle-loaded carbon black (Pt/CB, PtAg(3:1)/CB, PtAg(1:1)/CB) catalysts were prepared by a wet method. The resultant catalysts, moreover, were heat-treated in a N2 atmosphere at 200°C. The alloying of Pt with Ag for each PtAg/CB was confirmed by X-ray diffractometry and electron dispersive X-ray spectrometry. The heat-treatment did not change the crystal structure of the PtAg alloys and increased their particle size. X-ray photoelectron spectroscopy exhibited that stabilizers were completely removed from the PtAg alloy surface, and the Pt4f and Ag3d doublets due to metallic Pt and Ag, respectively, shifted to lower binding energies, supporting the alloying of Pt with Ag. Both PtAg/CB electrodes had two oxidation waves of glycerol irrespective of heat-treatment, which was different from the Pt/CB electrode. The onset potential of the first oxidation wave was -0.60 V, which was 0.20 V less positive than that for the Pt/CB electrode, indicating the alloying of Pt with Ag greatly improved the GOR activity of Pt. The heat-treated PtAg(3:1)/ CB electrode improved the GOR current density of the second oxidation peak. In the potentiostatic electrolysis at -0.1 and 0 V for both PtAg/CB electrodes, the ratio of oxidation current density at 60 min to that at 5 min (j<sub>60</sub>/j<sub>5</sub>), an indicator of the catalyst deterioration, at 0 V was higher than that at -0.1 V, because the adsorbed oxidation intermediates were greatly consumed at the larger overpotential. The heat-treatment of the PtAg(3:1)/CB electrode increased the j60</sub>/j5</sub> value at -0.1 V but decreased that at 0 V. This could be attributed to the formation of high-order oxidation intermediates which might have stronger poisoning effect.
文摘Techno-economic analysis of an indirect use of carbon dioxide within the route of glycerolysis of glycerol with urea is investigated. The results show that the net present value of the biodiesel-glycerol carbonate production by glycerolysis is higher than the biodiesel-glycerol carbonate production by direct carboxylationat at the end of the 12-year operation with similar capacities. The stochastic model has predicted that using glycerolysis route for the synthesis of glycerol carbonate production might increase the probability of getting positive net present value by about 15%.
基金a scholarship from the China Scholarship Council
文摘It is of importance to convert glycerol,the primary by-product from biodiesel manufacturing,to various valuable C3 chemicals,such as acrolein via dehydration,lactic acid,1,3-dihydroxyacetone via oxidation,and 1,3-propanediol,allyl alcohol via hydrogenolysis.As compared to petroleum-based resources,C3 chemicals from glycerol provide a benign,sustainable and atomically economic feature.Extensive heterogeneous catalysts have been designed,prepared and tested for these transformations.In recent five years,great progress,including high yields to target products over appropriate catalysts,insight into reaction mechanism and network,has been achieved.The present review systematically covers recent research progress on sustainable C3 chemical production from catalytic glycerol transformations.We hope that it will benefit future research on transformations of glycerol as well as other polyols.
基金supported by the National Natural Science Foundation of China(21690082,91545203,21473141)the Research Fund for the Doctorial Program of Higher Education(20130121130001)+2 种基金the Fundamental Research Funds for the Central Universities(20720160029)the Program for Innovative Research Team in University(IRT_14R31)Educational Research Projects for Young and Middle-aged Scholars of Fujian Province(JAT170019)
文摘Catalytic transformation of cellulose into value-added chemicals is of great importance for utilization of renewable and abundant biomass. Due to the high oxygen content, cellulose serves as an ideal candidate for the production of oxygenates, in particular lactic acid which is a versatile building block in chemical industry. The efficient conversion of cellulose to lactic acid generally requires selective activation of specific C-O and C-C bonds, and therefore multifunctional catalysts that combine several key reactions including hydrolysis, isomerization and retro-aldol fragmentation are highly desirable. This review article highlights the recently developed catalytic systems and catalysts for the selective transformation of cellulose and cellulose-derived carbohydrates into lactic acid, lactates and/or its esters. Emphases will be put on the reaction mechanism and key factors that exert effects on the catalytic performances. In addition, the catalytic transformation of glycerol, a C3 compound over-supplied from biodiesel industry, will also be surveyed. Recent advances in the development of new catalysts or strategies are analyzed and discussed to gain insight into the transformation of C3 compound to lactic acid.
文摘The selective hydrogenolysis of glycerol to 1,3-propanediol(1,3-PDO)is an attractive reaction due to the high demand for valorization of huge excess amounts of glycerol supply as well as the important application of 1,3-PDO in polyester industry.Nevertheless,the formation of 1,3-PDO is thermodynamically less favorable than 1,2-PDO,which necessitates the development of efficient catalysts to manipulate the reaction kinetics towards the 1,3-PDO formation.Among others,Pt-W based catalysts have shown promising activities and selectivities of 1,3-PDO although the reaction mechanism is not well addressed at the molecular level.In this short review,we have compared the performances of different Pt-W based catalysts and discussed the key factors influencing the activity and selectivity.Three possible reaction mechanisms have been discussed in terms of the synergy between Pt and WO_x and the origin of acid sites.Finally,the long-term stability of the Pt-W catalysts has been discussed.We hope this review will provide useful information for the development of more efficient catalysts for this important reaction.
