A series of Mn/CeO2-Al2O3 and K/CeO2-Al2O3 catalysts for hydrogenation of benzoic acid to benzaldehyde were prepared to investigate the effect of Mn, K addition on CeO2-Al2O3 catalyst. X-ray diffraction (XRD) and H2-t...A series of Mn/CeO2-Al2O3 and K/CeO2-Al2O3 catalysts for hydrogenation of benzoic acid to benzaldehyde were prepared to investigate the effect of Mn, K addition on CeO2-Al2O3 catalyst. X-ray diffraction (XRD) and H2-temperature-programmed reduction (H2-TPR) results suggested that the interaction between CeO2 and MnOx enhanced the reducibility of catalysts and therefore benzoic acid conversion. The addition of K increased the number of basic number on the catalyst which leads to a high selectivity to benzaldehyde, but excessive addition imposed negative effects on the catalyst performance. A Mn-K/CeO2-Al2O3 catalyst was developed and investigated in the reaction. The simultaneous addition of Mn and K enhanced not only the catalytic activity but also the capacity to resist the coke formation over catalyst.展开更多
The effect of different concentrations of benzaldehyde on the electrodeposition of Ni–W alloy coatings on a mild steel substrate from a citrate electrolyte was investigated in this study. The electrolytic alkaline ba...The effect of different concentrations of benzaldehyde on the electrodeposition of Ni–W alloy coatings on a mild steel substrate from a citrate electrolyte was investigated in this study. The electrolytic alkaline bath(p H 8.0) contained stoichiometric amounts of nickel sulfate, sodium tungstate, and trisodium citrate as precursors. The corrosion resistance of the Ni–W-alloy-coated specimens in 0.2 mol/L H2SO4 was studied using various electrochemical techniques. Tafel polarization studies reveal that the alloy coatings obtained from the bath containing 50 ppm benzaldehyde exhibit a protection efficiency of 95.33%. The corrosion rate also decreases by 21.5 times compared with that of the blank. A higher charge-transfer resistance of 1159.40 ?·cm2 and a lower double-layer capacitance of 29.4 μF·cm-2 further confirm the better corrosion resistance of the alloy coating. X-ray diffraction studies reveal that the deposits on the mild steel surface are consisted of nanocrystals. A lower surface roughness value(Rmax) of the deposits is confirmed by atomic force microscopy.展开更多
In this study, liquid-phase aerobic oxidation of toluene catalyzed by Mn–Mo oxide was conducted in a 1.0 L batch reactor. The macroscopic kinetics of toluene consumption and benzaldehyde generation at 413–443 K were...In this study, liquid-phase aerobic oxidation of toluene catalyzed by Mn–Mo oxide was conducted in a 1.0 L batch reactor. The macroscopic kinetics of toluene consumption and benzaldehyde generation at 413–443 K were obtained from a combination of experimental observation and hypothetical models. The results clearly showed that both the oxidation rate of toluene and generation rate of the aromatic product were proportional to the concentration of the substrate, the partial pressure of oxygen and the surface area of the catalyst. The energy barrier of toluene oxidation to benzyl alcohol was the highest(≈ 81 kJ mol^(-1)), while that of benzyl alcohol oxidation to benzaldehyde was the lowest(≈ 57 kJ mol^(-1)). Moreover, the activation energy of further oxidation of benzaldehyde in an acetic acid solvent was only slightly lower(≈ 1.9 kJ mol^(-1)) than that of toluene oxidation. Significantly, the transformation of benzyl alcohol indeed contributed to the generation of benzaldehyde and this step conformed to a first-order parallel-consecutive model. Increased reaction temperature and residence time favored the transformation of benzyl alcohol to benzaldehyde. In addition, doping with molybdenum at Mn/Mo = 3/1 enhanced the catalytic performance of the heterogeneous catalyst and was attributed to the presence of a synergetic effect between different metal cations. Regarding the microscopic kinetics, the LH-OS-ND mechanism(Langmuir–Hinshelwood adsorption of reagents on the same type of active sites and non-dissociative adsorption of oxygen) was verified as responsible for the heterogeneous oxidation of toluene. Oxygen and benzaldehyde were weakly adsorbed(Δ H_(ads,Oxy) ≈^(-1)5 kJ mol^(-1), Δ H _(ads)0,Bald) ≈-30 kJ mol^(-1)), but showed strong mobility(Δ S_(ads,Oxy) ≈-22 J mol^(-1) K^(-1)), Δ S_(ads,Bald) ≈-39 J mol^(-1) K^(-1)). The fundamental intrinsic rates were deduced based on the LH-OS-ND mechanism and showed great consistency with the macroscopic results.展开更多
In this paper, a new catalyst system V-Cs-Cu-Tl was studied in the gas phase selective oxidation for p-tert butyl toluene to p-tert benzaldehyde. The catalyst system was prepared by impregnation method. The results ob...In this paper, a new catalyst system V-Cs-Cu-Tl was studied in the gas phase selective oxidation for p-tert butyl toluene to p-tert benzaldehyde. The catalyst system was prepared by impregnation method. The results obtained are optimum value and have good advantages in environmental protection.展开更多
This paper has studied the recycling of the oxidation mediator Mn(Ⅲ)/Mn(Ⅱ) and sulfuric acid solution in process of indirect electrosynthesis of benzaldehyde. Experimental resalts show that mis recycling may be real...This paper has studied the recycling of the oxidation mediator Mn(Ⅲ)/Mn(Ⅱ) and sulfuric acid solution in process of indirect electrosynthesis of benzaldehyde. Experimental resalts show that mis recycling may be realized When electrolysis and synthetic reaction are carried out in the same concentration of 60% H2SO4 separately, then there will be no waste discharged, energy consumption will be decreased and almost no current efficiency will be lossed during recycling process. The optimun current efficiency is 76%, yield of benzaldehyde is 64%.展开更多
The dielectric constant e’ and dielectric loss e" of several mixtures of propionaldehyde-polyethylene glycol (system 1) and benzaldehyde-polyethylene glycol (system II) have been measured within the frequency ba...The dielectric constant e’ and dielectric loss e" of several mixtures of propionaldehyde-polyethylene glycol (system 1) and benzaldehyde-polyethylene glycol (system II) have been measured within the frequency band 105-107 Hz and the temperature range 20-50℃. The dielectric behaviour is discussed. on the other hand, the dielectric relaxation time T. activation energy △He, and entorpy change △Se for the dielectric relaxation as well as activation energy of viscous flow △Hv are calculated for the same temperature range. It is suggested that the observed increase in T values with increas.ng glycol content is due to an increase in the hydrogen bonding in the aggregates or clusters which would be formed between the carbonyl group of the aldehyde and the hydrogen atoms from the glycot molecules. In addition， the higher values of T, △He, and △Se in case of system (II) than that in case of system (I) may be due to the greater volume of the aggregates and the stronger dipole-dipole forces in system (II) compared with those in system (I).展开更多
The hydrogenation of benzaldehyde over a series of nickel-containing mesoporous silicas with different nickel contents was studied at atmospheric pressure in the range temperature of 393 - 513 K under H2 ?ow. These ma...The hydrogenation of benzaldehyde over a series of nickel-containing mesoporous silicas with different nickel contents was studied at atmospheric pressure in the range temperature of 393 - 513 K under H2 ?ow. These materials (noted Nin-HMS with n = Si/Ni = 50, 25, 15) have been prepared at room temperature using a route based on hydrogen bonding and self-assembly between neutral primary amine micelles (S0) and neutral inorganic precursors (I0). They were characterized by their chemical analysis, BET surface area, XRD, FT-IR, and SEM microscopy. The obtained products were benzylalcohol, toluene, benzene with yields depending on the nickel content (Si/Ni ratio) and reaction temperature. The products of benzaldehyde hydrogenation (benzylalcohol, and toluene) and hydrogenolysis (benzene) were preferentially formed at low/middle and high reaction temperature respectively. The mesoporous Ni-containing materials were very active hydrogenation catalysts with almost 90% selectivity to benzylalcohol product and showed excellent stability. A mechanism in which the reaction could be initiated by a benzaldehyde reduction over Nin-HMS materials under hydrogen flow with formation of reaction products is proposed.展开更多
The fluorescence emission wavelength [λmax(em)] values of three types of benzaldehyde derivatives, namely, ethylene acetals (1-Ys), 4-nitrophenylhydrazones (2-Ys) and phenylhydrazones (3-Ys), have been measured. Corr...The fluorescence emission wavelength [λmax(em)] values of three types of benzaldehyde derivatives, namely, ethylene acetals (1-Ys), 4-nitrophenylhydrazones (2-Ys) and phenylhydrazones (3-Ys), have been measured. Correlation analyses by the dual-parameter equation show that the λmax(em) values of 1-Ys are mainly affected by the spin-delocalization effects of the substituents, while those of 2-Ys are mainly affected by the polar effects. However,those of 3-Ys are independent of the substituents.展开更多
Biomass pyrolysis oil can be improved effectively by electrocatalytic hydrogenation(ECH).However,the unclear interactions among different components lead to low bio-oil upgrading efficiency in the conversion process.H...Biomass pyrolysis oil can be improved effectively by electrocatalytic hydrogenation(ECH).However,the unclear interactions among different components lead to low bio-oil upgrading efficiency in the conversion process.Herein,benzaldehyde and phenol,as common compounds in bio-oil,were chosen as model compounds.The interactions between the two components were explored in the ECH process by combining experiments and theoretical calculations.Results showed that phenol could accelerate the conversion of benzaldehyde in the ECH.The selectivity of benzyl alcohol was increased from 60.9%of unadded phenol to 99.1%with 30 mmol/L phenol concentration at 5 h.Benzaldehyde inhibited the ECH of phenol.In the presence of benzaldehyde,the conversion rate of phenol was below 10.0%with no cyclohexanone and cyclohexanol formation at 5 h.The density functional theory(DFT)calculations revealed that the phenol could promote the adsorption of benzaldehyde and facilitate the targeted conversion of benzaldehyde on the active site by lowering the reaction energy barrier.The research on the interaction between phenol and benzaldehyde in the ECH provides a theoretical basis for the application of ECH in practical bio-oil upgrading.展开更多
In this study, Al_2O_3-washcoated SiC(Al_2O_3–SiC) foams and Al_2O_3 powder were employed as the supports of a Ni catalyst for the liquid-phase hydrogenation of benzaldehyde. A series of Ni/Al_2O_3–SiC foam catalyst...In this study, Al_2O_3-washcoated SiC(Al_2O_3–SiC) foams and Al_2O_3 powder were employed as the supports of a Ni catalyst for the liquid-phase hydrogenation of benzaldehyde. A series of Ni/Al_2O_3–SiC foam catalysts and Ni/Al_2O_3 powder catalysts with a Ni loading from 10 wt% to 37 wt% of the weight of Al_2O_3 were first prepared by a deposition–precipitation(DP) method. The catalytic activity and recyclability of both kinds of catalysts were then compared. Although it had a smaller accessible surface area with the reactant, the foam catalyst with a Ni loading of 16 wt% exhibited a slightly higher conversion of benzaldehyde after 6 h(of 99.3%) in comparison with the Ni/Al_2O_3 catalyst with identical Ni loading(conversion of 97.5%). When the Ni loading increased from 16 wt% to 37 wt%, the reaction rate obtained with the foam catalyst increased significantly from 0.108 to 0.204 mol L^(-1)h^(-1), whereas the reaction rate obtained with the powder catalyst increased from 0.106 to 0.123 mol L^(-1)h^(-1). Furthermore, the specific activity(moles of benzaldehyde consumed by 1 g min^(-1)of Ni) of the foam catalyst with a Ni loading above 30 wt% was superior to that of the powder catalyst because of its smaller Ni-particle size and higher mass-transfer rate. The foam catalyst displayed a high recyclability as a function of run times owing to the strong interaction between the Ni component and the Al_2O_3 coating. The conversion of benzaldehyde over the foam catalyst remained almost unchanged after being used 8 times. In comparison, a drop of 43% in the conversion of benzaldehyde with the powder catalyst was observed after being used 7 times due to the leaching of the Ni component.展开更多
Converting water into hydrogen fuel and oxidizing benzyl alcohol to benzaldehyde simultaneously under visible light illumination is of great significance,but the fast recombination of photogenerated carriers in photoc...Converting water into hydrogen fuel and oxidizing benzyl alcohol to benzaldehyde simultaneously under visible light illumination is of great significance,but the fast recombination of photogenerated carriers in photocatalysts seriously decreases the conversion efficiency.Herein,a novel dual-functional 0D Cd_(0.5)Zn_(0.5)S/2D Ti_(3)C2 hybrid was fabricated by a solvothermally in-situ generated assembling method.The Cd_(0.5)Zn_(0.5)S nano-spheres with a fluffy surface completely and uniformly covered the ultrathin Ti_(3)C2 nanosheets,leading to the increased Schottky barrier(SB)sites due to a large contact area,which could accelerate the electron–hole separation and improve the light utilization.The optimized Cd_(0.5)Zn_(0.5)S/Ti_(3)C2 hybrid simultaneously presents a hydrogen evolution rate of 5.3 mmol/(g·h)and a benzaldehyde production rate of 29.3 mmol/(g·h),which are~3.2 and 2 times higher than those of pristine Cd_(0.5)Zn_(0.5)S,respectively.Both the multiple experimental measurements and the density functional theory(DFT)calculations further demonstrate the tight connection between Cd_(0.5)Zn_(0.5)S and Ti_(3)C2,formation of Schottky junction,and efficient photogenerated electron–hole separation.This paper suggests a dual-functional composite catalyst for photocatalytic hydrogen evolution and benzaldehyde production,and provides a new strategy for preventing the photogenerated electrons and holes from recombining by constructing a 0D/2D heterojunction with increased SB sites.展开更多
The optical active alkyne-bridged Mo-Co heterometal complexes are synthesized by the chiral phase transfer catalyst (N-benzylcinchorin chloride) induced metal exchange reaction. The complex is used as catalyst to prom...The optical active alkyne-bridged Mo-Co heterometal complexes are synthesized by the chiral phase transfer catalyst (N-benzylcinchorin chloride) induced metal exchange reaction. The complex is used as catalyst to promote the asymmetric addition of diethylzinc to benzaldehyde. The ee value of the product alcohol is 5.7%, which illustrates the asymmetric induction of the tetrahedral framework chirality in asymmetric catalysis reaction for the first time.展开更多
Marine fungi are important members of the marine microbiome,which have been paid growing attention by scientists in recent years.The secondary metabolites of marine fungi have been reported to contain rich and diverse...Marine fungi are important members of the marine microbiome,which have been paid growing attention by scientists in recent years.The secondary metabolites of marine fungi have been reported to contain rich and diverse compounds with novel structures(Chen et al.,2019).Aspergillus terreus,the higher level marine fungus of the Aspergillus genus(family of Trichocomaceae,order of Eurotiales,class of Euro・tiomycetes,phylum of Ascomycota).展开更多
The benzophenone/tertiaryamine system is one of the most important photoinitiation systems in photocuring acrylates. The subjects of how to increase the quantum yield or how to extend the spectral absorption range hav...The benzophenone/tertiaryamine system is one of the most important photoinitiation systems in photocuring acrylates. The subjects of how to increase the quantum yield or how to extend the spectral absorption range have atracted a lot of attention. The present authors have reported before the rate-accelerating effect of oxygen展开更多
The catalytic conversion of biomass-derived feedstocks into functional molecules is of significance to synthetic organic chemistry.Herein,through a palladium-catalyzed reductive annulation reaction of resorcinols and ...The catalytic conversion of biomass-derived feedstocks into functional molecules is of significance to synthetic organic chemistry.Herein,through a palladium-catalyzed reductive annulation reaction of resorcinols and 2-nitrobenzaldehydes,we present a new approach for the direct synthesis of acridinone derivatives,featuring operational simplicity,good substrate compatibility,and readily available feedstocks.展开更多
The dearomative[5+1]annulation of 2-methylindoles with new five-membered synthons O-alkyl orthooxybenzaldehydes was developed unprecedentedly through cascade[1,5]-hydride transfer/dearomativecyclization in HFIP for th...The dearomative[5+1]annulation of 2-methylindoles with new five-membered synthons O-alkyl orthooxybenzaldehydes was developed unprecedentedly through cascade[1,5]-hydride transfer/dearomativecyclization in HFIP for the synthesis of spirochromanes bearing the 2-methylindolenine skeleton.Inaddition,the dual alkylation of the methyl group of 2-methylindolenines was achieved by sequential operation through the redox neutral[5+1]annulation with the second five-membered synthon N-alkylortho-aminobenzaldehyde,providing the chromane and tetrahydroquinoline fused spiroindolenines ingood yields.Furthermore,the auxiliary group that facilitates the hydride transfer process could be simplyremoved.展开更多
Benzaldehyde lyase(BAL)is an enzyme which was originally found from Pseudomonas fluorescens biovar I.It has long been used in the formation of a C-C bond.BAL can exclusively yield(R)-enantioselective products from the...Benzaldehyde lyase(BAL)is an enzyme which was originally found from Pseudomonas fluorescens biovar I.It has long been used in the formation of a C-C bond.BAL can exclusively yield(R)-enantioselective products from the synthesis ofα-hydroxy ketones and has so far been explored as an important enzyme to prepare the corresponding intermediate of pharmaceuticals.Due to its substrate spectrum and stereospecificity,this enzyme extends the synthetic potential for carboligations appreciably.In this review,we highlight the biotransformation applications of BAL in recent years,some of which have achieved intriguing results and provided the theoretical basis for drug development and industrial purpose in the future.展开更多
基金Project supported by the Science and Technology Department of Zhejiang Province,China (2007C21103)
文摘A series of Mn/CeO2-Al2O3 and K/CeO2-Al2O3 catalysts for hydrogenation of benzoic acid to benzaldehyde were prepared to investigate the effect of Mn, K addition on CeO2-Al2O3 catalyst. X-ray diffraction (XRD) and H2-temperature-programmed reduction (H2-TPR) results suggested that the interaction between CeO2 and MnOx enhanced the reducibility of catalysts and therefore benzoic acid conversion. The addition of K increased the number of basic number on the catalyst which leads to a high selectivity to benzaldehyde, but excessive addition imposed negative effects on the catalyst performance. A Mn-K/CeO2-Al2O3 catalyst was developed and investigated in the reaction. The simultaneous addition of Mn and K enhanced not only the catalytic activity but also the capacity to resist the coke formation over catalyst.
文摘The effect of different concentrations of benzaldehyde on the electrodeposition of Ni–W alloy coatings on a mild steel substrate from a citrate electrolyte was investigated in this study. The electrolytic alkaline bath(p H 8.0) contained stoichiometric amounts of nickel sulfate, sodium tungstate, and trisodium citrate as precursors. The corrosion resistance of the Ni–W-alloy-coated specimens in 0.2 mol/L H2SO4 was studied using various electrochemical techniques. Tafel polarization studies reveal that the alloy coatings obtained from the bath containing 50 ppm benzaldehyde exhibit a protection efficiency of 95.33%. The corrosion rate also decreases by 21.5 times compared with that of the blank. A higher charge-transfer resistance of 1159.40 ?·cm2 and a lower double-layer capacitance of 29.4 μF·cm-2 further confirm the better corrosion resistance of the alloy coating. X-ray diffraction studies reveal that the deposits on the mild steel surface are consisted of nanocrystals. A lower surface roughness value(Rmax) of the deposits is confirmed by atomic force microscopy.
基金supported by the National Natural Science Foundation of China (No. 21376163)
文摘In this study, liquid-phase aerobic oxidation of toluene catalyzed by Mn–Mo oxide was conducted in a 1.0 L batch reactor. The macroscopic kinetics of toluene consumption and benzaldehyde generation at 413–443 K were obtained from a combination of experimental observation and hypothetical models. The results clearly showed that both the oxidation rate of toluene and generation rate of the aromatic product were proportional to the concentration of the substrate, the partial pressure of oxygen and the surface area of the catalyst. The energy barrier of toluene oxidation to benzyl alcohol was the highest(≈ 81 kJ mol^(-1)), while that of benzyl alcohol oxidation to benzaldehyde was the lowest(≈ 57 kJ mol^(-1)). Moreover, the activation energy of further oxidation of benzaldehyde in an acetic acid solvent was only slightly lower(≈ 1.9 kJ mol^(-1)) than that of toluene oxidation. Significantly, the transformation of benzyl alcohol indeed contributed to the generation of benzaldehyde and this step conformed to a first-order parallel-consecutive model. Increased reaction temperature and residence time favored the transformation of benzyl alcohol to benzaldehyde. In addition, doping with molybdenum at Mn/Mo = 3/1 enhanced the catalytic performance of the heterogeneous catalyst and was attributed to the presence of a synergetic effect between different metal cations. Regarding the microscopic kinetics, the LH-OS-ND mechanism(Langmuir–Hinshelwood adsorption of reagents on the same type of active sites and non-dissociative adsorption of oxygen) was verified as responsible for the heterogeneous oxidation of toluene. Oxygen and benzaldehyde were weakly adsorbed(Δ H_(ads,Oxy) ≈^(-1)5 kJ mol^(-1), Δ H _(ads)0,Bald) ≈-30 kJ mol^(-1)), but showed strong mobility(Δ S_(ads,Oxy) ≈-22 J mol^(-1) K^(-1)), Δ S_(ads,Bald) ≈-39 J mol^(-1) K^(-1)). The fundamental intrinsic rates were deduced based on the LH-OS-ND mechanism and showed great consistency with the macroscopic results.
文摘In this paper, a new catalyst system V-Cs-Cu-Tl was studied in the gas phase selective oxidation for p-tert butyl toluene to p-tert benzaldehyde. The catalyst system was prepared by impregnation method. The results obtained are optimum value and have good advantages in environmental protection.
文摘This paper has studied the recycling of the oxidation mediator Mn(Ⅲ)/Mn(Ⅱ) and sulfuric acid solution in process of indirect electrosynthesis of benzaldehyde. Experimental resalts show that mis recycling may be realized When electrolysis and synthetic reaction are carried out in the same concentration of 60% H2SO4 separately, then there will be no waste discharged, energy consumption will be decreased and almost no current efficiency will be lossed during recycling process. The optimun current efficiency is 76%, yield of benzaldehyde is 64%.
文摘The dielectric constant e’ and dielectric loss e" of several mixtures of propionaldehyde-polyethylene glycol (system 1) and benzaldehyde-polyethylene glycol (system II) have been measured within the frequency band 105-107 Hz and the temperature range 20-50℃. The dielectric behaviour is discussed. on the other hand, the dielectric relaxation time T. activation energy △He, and entorpy change △Se for the dielectric relaxation as well as activation energy of viscous flow △Hv are calculated for the same temperature range. It is suggested that the observed increase in T values with increas.ng glycol content is due to an increase in the hydrogen bonding in the aggregates or clusters which would be formed between the carbonyl group of the aldehyde and the hydrogen atoms from the glycot molecules. In addition， the higher values of T, △He, and △Se in case of system (II) than that in case of system (I) may be due to the greater volume of the aggregates and the stronger dipole-dipole forces in system (II) compared with those in system (I).
文摘The hydrogenation of benzaldehyde over a series of nickel-containing mesoporous silicas with different nickel contents was studied at atmospheric pressure in the range temperature of 393 - 513 K under H2 ?ow. These materials (noted Nin-HMS with n = Si/Ni = 50, 25, 15) have been prepared at room temperature using a route based on hydrogen bonding and self-assembly between neutral primary amine micelles (S0) and neutral inorganic precursors (I0). They were characterized by their chemical analysis, BET surface area, XRD, FT-IR, and SEM microscopy. The obtained products were benzylalcohol, toluene, benzene with yields depending on the nickel content (Si/Ni ratio) and reaction temperature. The products of benzaldehyde hydrogenation (benzylalcohol, and toluene) and hydrogenolysis (benzene) were preferentially formed at low/middle and high reaction temperature respectively. The mesoporous Ni-containing materials were very active hydrogenation catalysts with almost 90% selectivity to benzylalcohol product and showed excellent stability. A mechanism in which the reaction could be initiated by a benzaldehyde reduction over Nin-HMS materials under hydrogen flow with formation of reaction products is proposed.
文摘The fluorescence emission wavelength [λmax(em)] values of three types of benzaldehyde derivatives, namely, ethylene acetals (1-Ys), 4-nitrophenylhydrazones (2-Ys) and phenylhydrazones (3-Ys), have been measured. Correlation analyses by the dual-parameter equation show that the λmax(em) values of 1-Ys are mainly affected by the spin-delocalization effects of the substituents, while those of 2-Ys are mainly affected by the polar effects. However,those of 3-Ys are independent of the substituents.
基金gratitude to Shenzhen Science and Technology Program(No.JCYJ20200109150210400).
文摘Biomass pyrolysis oil can be improved effectively by electrocatalytic hydrogenation(ECH).However,the unclear interactions among different components lead to low bio-oil upgrading efficiency in the conversion process.Herein,benzaldehyde and phenol,as common compounds in bio-oil,were chosen as model compounds.The interactions between the two components were explored in the ECH process by combining experiments and theoretical calculations.Results showed that phenol could accelerate the conversion of benzaldehyde in the ECH.The selectivity of benzyl alcohol was increased from 60.9%of unadded phenol to 99.1%with 30 mmol/L phenol concentration at 5 h.Benzaldehyde inhibited the ECH of phenol.In the presence of benzaldehyde,the conversion rate of phenol was below 10.0%with no cyclohexanone and cyclohexanol formation at 5 h.The density functional theory(DFT)calculations revealed that the phenol could promote the adsorption of benzaldehyde and facilitate the targeted conversion of benzaldehyde on the active site by lowering the reaction energy barrier.The research on the interaction between phenol and benzaldehyde in the ECH provides a theoretical basis for the application of ECH in practical bio-oil upgrading.
基金the financial support of the project from the National Key Research&Development Program of China(No.2017YFB0310405)
文摘In this study, Al_2O_3-washcoated SiC(Al_2O_3–SiC) foams and Al_2O_3 powder were employed as the supports of a Ni catalyst for the liquid-phase hydrogenation of benzaldehyde. A series of Ni/Al_2O_3–SiC foam catalysts and Ni/Al_2O_3 powder catalysts with a Ni loading from 10 wt% to 37 wt% of the weight of Al_2O_3 were first prepared by a deposition–precipitation(DP) method. The catalytic activity and recyclability of both kinds of catalysts were then compared. Although it had a smaller accessible surface area with the reactant, the foam catalyst with a Ni loading of 16 wt% exhibited a slightly higher conversion of benzaldehyde after 6 h(of 99.3%) in comparison with the Ni/Al_2O_3 catalyst with identical Ni loading(conversion of 97.5%). When the Ni loading increased from 16 wt% to 37 wt%, the reaction rate obtained with the foam catalyst increased significantly from 0.108 to 0.204 mol L^(-1)h^(-1), whereas the reaction rate obtained with the powder catalyst increased from 0.106 to 0.123 mol L^(-1)h^(-1). Furthermore, the specific activity(moles of benzaldehyde consumed by 1 g min^(-1)of Ni) of the foam catalyst with a Ni loading above 30 wt% was superior to that of the powder catalyst because of its smaller Ni-particle size and higher mass-transfer rate. The foam catalyst displayed a high recyclability as a function of run times owing to the strong interaction between the Ni component and the Al_2O_3 coating. The conversion of benzaldehyde over the foam catalyst remained almost unchanged after being used 8 times. In comparison, a drop of 43% in the conversion of benzaldehyde with the powder catalyst was observed after being used 7 times due to the leaching of the Ni component.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51902137 and 51672113)the Key Research and Development Plan(Grant No.BE2019094)+1 种基金the Qing Lan Project([2016]15)of Jiangsu ProvinceThe calculations were carried out by the Advanced Computing East China Sub-center and Big Data Center of Southeast University。
文摘Converting water into hydrogen fuel and oxidizing benzyl alcohol to benzaldehyde simultaneously under visible light illumination is of great significance,but the fast recombination of photogenerated carriers in photocatalysts seriously decreases the conversion efficiency.Herein,a novel dual-functional 0D Cd_(0.5)Zn_(0.5)S/2D Ti_(3)C2 hybrid was fabricated by a solvothermally in-situ generated assembling method.The Cd_(0.5)Zn_(0.5)S nano-spheres with a fluffy surface completely and uniformly covered the ultrathin Ti_(3)C2 nanosheets,leading to the increased Schottky barrier(SB)sites due to a large contact area,which could accelerate the electron–hole separation and improve the light utilization.The optimized Cd_(0.5)Zn_(0.5)S/Ti_(3)C2 hybrid simultaneously presents a hydrogen evolution rate of 5.3 mmol/(g·h)and a benzaldehyde production rate of 29.3 mmol/(g·h),which are~3.2 and 2 times higher than those of pristine Cd_(0.5)Zn_(0.5)S,respectively.Both the multiple experimental measurements and the density functional theory(DFT)calculations further demonstrate the tight connection between Cd_(0.5)Zn_(0.5)S and Ti_(3)C2,formation of Schottky junction,and efficient photogenerated electron–hole separation.This paper suggests a dual-functional composite catalyst for photocatalytic hydrogen evolution and benzaldehyde production,and provides a new strategy for preventing the photogenerated electrons and holes from recombining by constructing a 0D/2D heterojunction with increased SB sites.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 29871061).
文摘The optical active alkyne-bridged Mo-Co heterometal complexes are synthesized by the chiral phase transfer catalyst (N-benzylcinchorin chloride) induced metal exchange reaction. The complex is used as catalyst to promote the asymmetric addition of diethylzinc to benzaldehyde. The ee value of the product alcohol is 5.7%, which illustrates the asymmetric induction of the tetrahedral framework chirality in asymmetric catalysis reaction for the first time.
基金This work was supported by the Natural Science Foundation of Guangdong Province(No.2018A030307046)the Basic Research Project of Shenzhen Science and Technology Innovation Commission(No.JCYJ20190813105005619)+2 种基金the Shenzhen Dapeng New District Industrial Development Fund(No.KY20180203)the Shenzhen Dapeng New District Scientific and Technological Research and Development Fund(No.KJYF202001-07)the the Innovation and Development Project about Marine Economy Demostration of Zhanjiang City(No.XM-202008-01B1),China.
文摘Marine fungi are important members of the marine microbiome,which have been paid growing attention by scientists in recent years.The secondary metabolites of marine fungi have been reported to contain rich and diverse compounds with novel structures(Chen et al.,2019).Aspergillus terreus,the higher level marine fungus of the Aspergillus genus(family of Trichocomaceae,order of Eurotiales,class of Euro・tiomycetes,phylum of Ascomycota).
文摘The benzophenone/tertiaryamine system is one of the most important photoinitiation systems in photocuring acrylates. The subjects of how to increase the quantum yield or how to extend the spectral absorption range have atracted a lot of attention. The present authors have reported before the rate-accelerating effect of oxygen
基金We thank the National Natural Science Foundation of China(21971071)the Natural Science Foundation of Guangdong Province(2021A1515010155 and 2019B090905007)the Fundamental Research Funds for the Central Universities(2020ZYGXZR075)for financial support.
文摘The catalytic conversion of biomass-derived feedstocks into functional molecules is of significance to synthetic organic chemistry.Herein,through a palladium-catalyzed reductive annulation reaction of resorcinols and 2-nitrobenzaldehydes,we present a new approach for the direct synthesis of acridinone derivatives,featuring operational simplicity,good substrate compatibility,and readily available feedstocks.
基金supported by the National Natural Science Foundation of China(21978144,21672208 and 21372218)the Support Plan on Science and Technology for Youth Innovation of Universities in Shandong Province(2019KJM002)+1 种基金the financial support from the Talents of High Level Scientific Research Foundation(6651118009 and 6631121010)the start-up fund for the Recruited Talent of Xihua University(Z201098).
文摘The dearomative[5+1]annulation of 2-methylindoles with new five-membered synthons O-alkyl orthooxybenzaldehydes was developed unprecedentedly through cascade[1,5]-hydride transfer/dearomativecyclization in HFIP for the synthesis of spirochromanes bearing the 2-methylindolenine skeleton.Inaddition,the dual alkylation of the methyl group of 2-methylindolenines was achieved by sequential operation through the redox neutral[5+1]annulation with the second five-membered synthon N-alkylortho-aminobenzaldehyde,providing the chromane and tetrahydroquinoline fused spiroindolenines ingood yields.Furthermore,the auxiliary group that facilitates the hydride transfer process could be simplyremoved.
基金The author would like to thank Dr.K.Kaliyaperumal,Dr.M.Fredimoses and Dr.B.Sachin for their careful revisions of this work.
文摘Benzaldehyde lyase(BAL)is an enzyme which was originally found from Pseudomonas fluorescens biovar I.It has long been used in the formation of a C-C bond.BAL can exclusively yield(R)-enantioselective products from the synthesis ofα-hydroxy ketones and has so far been explored as an important enzyme to prepare the corresponding intermediate of pharmaceuticals.Due to its substrate spectrum and stereospecificity,this enzyme extends the synthetic potential for carboligations appreciably.In this review,we highlight the biotransformation applications of BAL in recent years,some of which have achieved intriguing results and provided the theoretical basis for drug development and industrial purpose in the future.
