Co-reporter:Fei Wang, Xuan Kang, Ma-xi Zhou, Xing-hui Yang, Li-jing Gao, Guo-min Xiao
Applied Catalysis A: General 2017 Volume 539(Volume 539) pp:
Publication Date(Web):5 June 2017
DOI:10.1016/j.apcata.2017.04.005
•Introduction of Zn species improved conversion efficiency of carbon in glycerol.•Sn/HZSM-5 modified by ZnO film of 20 ALD cycles lead to better synergistic effect.•Sn particles on HZSM-5 would be completely packaged by ZnO film of 40 ALD cycles.•The catalyst reusability could be tremendously improved by ALD introduced ZnO film.The chemoselective catalytic conversion of glycerol into high value-added aromatics (GTA) can greatly enhance the economic profits in biodiesel and biomass industry chain. In order to enhance the aromatization activity, stability and conversion efficiency of carbon in glycerol into aromatics during the GTA process, Zn species, which could directly convert alkenes originated from deoxygenation of glycerol into aromatics through dehydrogenation reaction, was introduced into Sn/HZSM-5 zeolite via atomic layer deposition (ALD) and incipient wet impregnation (IWI) method. Compared with impregnated ZnO modified Sn/HZSM-5, ZnO introduced by 20 ALD cycles into Sn/HZSM-5 deposited in the form of thin film, which not only fully coated both HZSM-5 external and internal surface, but also partially covered impregnated Sn particles. This film stabilized the oxidation state of loaded SnOx species which acted as catalytically active materials and further healed HZSM-5 structural defects, leading to the better synergistic effect among HZSM-5 zeolite, impregnated Sn particles and ALD introduced ZnO films. Besides, the reusability of this catalyst could be tremendously improved due to the protective effect of introduced ALD ZnO film which could prevent irreversible dealumination of HZSM-5 from exposure of HZSM-5 framework to steam during GTA reaction and regeneration procedure. However, when the deposited ZnO ALD cycle number reached 40, Sn particles on HZSM-5 could be completely packaged by ZnO film, on which occasion Sn could not participate in the GTA process, thereby leading to the reduction in both aromatics yields and catalyst lifetime.Download high-res image (205KB)Download full-size imageModification of a Sn/HZSM-5 catalyst by thin 20 ALD cycle deposited ZnO films lead to better synergistic aromatization effect.
Co-reporter:Lijing Gao, Wei Xu, Guomin Xiao
Chemical Engineering and Processing: Process Intensification 2017 Volume 122(Volume 122) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.cep.2017.09.019
•A universal model for biodiesel production in membrane reactor with solid catalysts and methanol recycle was established.•Reaction kinetics, LLE and pore model for filtration were considered in the model.•The composites in the membrane reaction system were calculated by the model and fit the experimental data well.A mathematical model based on the pore model of membrane, liquid–liquid equilibrium model and reaction kinetics model for biodiesel production in membrane reactor was developed. The parameters of the model were calculated from the membrane reaction process of the transesterification between soybean oil and methanol catalyzed by KF/Ca-Mg-Al hydrotalcite. The biodiesel yield calculated by the model fitted the experimental data well. The model simulated results indicated that the membrane reaction system can be divided in biodiesel accumulation and membrane separation of biodiesel stage. In the studied temperature range, the biodiesel yield with the same reaction time increased with the increase in temperature. However, the maximum yields under of all temperatures were almost the same. The results proved that the membrane reactor can shift the transesterification equilibrium to the products side by continuously removing the products.Download high-res image (105KB)Download full-size image
Co-reporter:Xianghai Song, Yuanfeng Wu, Donghui Pan, Fufeng Cai, Guomin Xiao
Molecular Catalysis 2017 Volume 436(Volume 436) pp:
Publication Date(Web):1 July 2017
DOI:10.1016/j.mcat.2017.04.027
•Efficient C3N4 catalyst was developed to synthesize chloropropene carbonate from CO2.•Edge defects were assumed to be active sites for CO2 activation.•Cl atom and epoxide group in epichlorohydrin could activate each other.•Only minimal decrease in activity was observed after five cycles.As an abundant, nontoxic, cheap, and renewable carbon resource, carbon dioxide (CO2) has drawn much attention in recent years. The chemical fixation of CO2 for various synthetic transformations is a hot topic in current researches. In the present work, three kinds of carbon nitride (C3N4) were prepared and tested for the chemical fixation of CO2 to chloropronene carbonate (CPC). These catalysts were characterized by means of XRD, SEM, BET, IR, and XPS. The activity test demonstrated that u-C3N4 presents the best catalytic activity, which was attributed to the large amount of edge defects in the structure and its higher surface area. The superior reactivity of epichlorohydrin (ECH) compared with other epoxide was derived from the Cl atom in its structure, which can act as a co-catalyst for the reaction and activate epoxide group in ECH as well. The best result was obtained at 120 °C, 2 MPa initial CO2 pressure in 5 hours with an ECH conversion of 98.31% and CPC selectivity of 98.01%. The catalyst can be reused for five cycles with only minimal decrease in catalytic activity. Moreover, based on the experimental and characterization results a possible reaction mechanism was proposed.Chemical fixation of CO2 into chloropropene carbonate over carbon nitride.Download full-size image
Co-reporter:Fei Wang, Weiyin Xiao, Lijing Gao and Guomin Xiao
Catalysis Science & Technology 2016 vol. 6(Issue 9) pp:3074-3086
Publication Date(Web):26 Nov 2015
DOI:10.1039/C5CY01651G
A series of ZnO/HZSM-5 catalysts were prepared by atomic layer deposition (ALD) with different cycle numbers and tested for methanol to aromatics (MTA) reactions. The growth rate of Zn content monotonically decreases with increasing number of deposition cycles due to the “half-self-limiting” ALD-type growth mode for ZnO on HZSM-5 zeolite, in which the density of the regenerated reactive –OH sites in the HZSM-5 substrates was less than that of the consumed –OH sites in one cycle. The deposited ZnO existed as small nanocrystallites upon low ALD cycles. However, as the number of ALD cycles exceeds a certain value, the resulting ZnO grown on the HZSM-5 substrate exists in the form of a continuous coating with corrugated surfaces, which could effectively prevent damage to the HZSM-5 framework caused by exposure of the zeolite skeleton to steam during the reaction and regeneration processes. The ZnO/HZSM-5 catalyst treated with 40 ALD cycles was proved to be the optimum catalyst for MTA reactions, producing a nearly twofold increase in BTX aromatics (carbon yield of 60.3%) than the parent HZSM-5 (28.3% carbon yield of BTX aromatics). The catalyst prepared by ALD not only is more effective for the aromatization of methanol but also shows a more stable performance in the MTA process than that prepared by conventional methods (i.e. IWI and IE) with a comparable amount of Zn content. This better performance could be ascribed to the synergetic effect that occurred between the multinuclear oxygenated zinc sites and (ZnOH)+ sites formed during the ALD process, which would boost the transformation of inert low alkanes to aromatics.
Co-reporter:Fufeng Cai, Wei Zhu and Guomin Xiao
Catalysis Science & Technology 2016 vol. 6(Issue 13) pp:4889-4900
Publication Date(Web):29 Feb 2016
DOI:10.1039/C6CY00085A
In this work, ZrO2-promoted Cu–Al2O3 catalysts prepared by the co-precipitation method were used for the hydrogenolysis of glycerol to 1,2-propanediol in a fixed-bed reactor. These catalysts were fully characterized by BET, ICP, N2O chemisorption, XRD, H2-TPR, NH3-TPD, XPS, TEM and TGA. The relationship between the catalytic activity and the metal–support interaction was studied in detail. The experimental results showed that the addition of ZrO2 to Cu–Al2O3 could greatly enhance glycerol conversion and 1,2-propanediol selectivity. This improvement was related to the increase in the acidity and Cu dispersion on the catalytic surface. The optimal 20ZrCu–Al2O3 catalyst attained 97.1% glycerol conversion and 95.3% 1,2-propanediol selectivity. Furthermore, the effects of process parameters like solvent, reaction temperature, operating pressure, glycerol concentration and liquid flow rate on glycerol hydrogenolysis together with the catalyst stability were deeply investigated. Compared with the Cu–Al2O3 catalyst, the ZrO2-promoted Cu–Al2O3 catalyst had better stability and potential for practical application, which was likely due to the high Cu dispersion and strong interaction between copper and zirconium species.
Co-reporter:Fufeng Cai and Guomin Xiao
Catalysis Science & Technology 2016 vol. 6(Issue 14) pp:5656-5667
Publication Date(Web):11 Apr 2016
DOI:10.1039/C6CY00116E
In this work, a series of Cu–Co–Al catalysts with different Ce loadings were applied to the hydrogenolysis of glycerol to 1,2-propanediol in a fixed-bed flow reactor. The physicochemical properties of the synthesized catalysts were analyzed using BET, N2O chemisorption, SEM, TEM, XRD, H2-TPR, NH3-TPD and XPS techniques. Systematic characterization demonstrated that the incorporation of Ce into the Cu–Co–Al catalyst could effectively restrain the aggregation of active metal species as well as the growth of metallic particles during calcination and reduction, which resulted in the formation of highly dispersed active metals. Large amounts and superior strength of acid sites were present in the Ce-promoted Cu–Co–Al catalysts, as confirmed by NH3-TPD analysis. The reducible nature of the Cu–Co–Al catalyst greatly increased after the addition of Ce. The higher concentration of acid sites, excellent reducibility and highly dispersed active metals were responsible for the superior catalytic activity of the 8Ce/Cu–Co–Al catalyst and it attained 91.6% glycerol conversion and 92.4% 1,2-propanediol selectivity. In addition, the effects of different process parameters such as the solvent, reaction temperature, operating pressure, catalyst loading, glycerol concentration and liquid flow rate on glycerol hydrogenolysis together with the catalyst stability were studied in detail, showing that the Ce-promoted Cu–Co–Al catalyst had high efficiency and stability for glycerol hydrogenolysis.
Co-reporter:Jian Li, Jingjing Li, Yanqing Gao, Shibin Shang, Zhanqiang Song, and Guomin Xiao
ACS Sustainable Chemistry & Engineering 2016 Volume 4(Issue 9) pp:4685
Publication Date(Web):August 14, 2016
DOI:10.1021/acssuschemeng.6b00819
As a continuous study on the integrated application of volatile β-pinene as an abundant bioresource, the further and broader activity assessment of β-pinene analogues was necessary. On the basis of previous research, the larvicidal activities were carried out against two agricultural insect pests Plutella xylostella and Mythimna separata. In accordance with the overall insecticidal effect, it was remarkable that compounds 5k and 5l demonstrated extreme activity, with LC50 values 1.846 and 1.621 μg/mL against Plutella xylostella. The preliminary structure–activity relationship (SAR) was analyzed, and compounds with the appropriate amphipathic feature displayed more desirable performance. In the meantime, the quantitative structure–activity relationship (QSAR) model (R2 = 0.9485, F = 82.94, S2 = 0.0067) was built. The model indicated the most important structural feature was the μc value, which represented the total hybridization components of the molecular dipole. The work provided a potential and alternative approach to take advantage of a forest resource in agriculture.Keywords: Insecticidal activity; QSAR; Turpentine; β-Pinene
Co-reporter:Fei Wang, Weiyin Xiao, Lijing Gao and Guomin Xiao
RSC Advances 2016 vol. 6(Issue 49) pp:42984-42993
Publication Date(Web):26 Apr 2016
DOI:10.1039/C6RA03358J
The green production of aromatics from glycerol, a by-product of biodiesel manufacturing, is a potential alternative to the conventional production of aromatics through fossil fuel-based technology. In the present work the one-step catalytic conversion of glycerol to aromatics has been conducted over pure HZSM-5 and several metal species (Zn, Mo, Sn, Ni and Ag) modified HZSM-5 catalysts. Both the roles of metal species and HZSM-5 supports played during the GTA (glycerol to aromatics) procedure as well as the whole GTA catalytic process were investigated in this article. There are two main routes existing in zeolite upgrading of glycerol to aromatics, one by aldol condensation of glycerol dehydration products, in which oxygen in the glycerol is removed in the form of H2O, whereas the other by oligomerization of olefins originated from the decarbonylation of glycerin dewatered products, in which oxygen in the feedstock is removed in the form of CO or CO2. Among all the catalysts tested, 2.34 wt% Sn/HZSM-5, which exhibits 21.1 wt% in BTX aromatics yield and 10 h catalyst lifetime compared to the bare HZSM-5 (13.9 wt% of BTX aromatics and 5.5 h catalyst lifetime) and our previously reported optimum base-treated HZSM-5 catalyst (25.2 carbon yields%, i.e. 16.7 wt% of BTX aromatics), has demonstrated to be a potential candidate in the catalytic upgrading of glycerol. The incorporated Sn cations may preferentially accelerate the competitive decarbonylation steps (i.e., acetone → butene), and thus, facilitated the generation of xylene aromatics. Furthermore, the incorporated Sn cations could heal the framework defects in the HZSM-5 crystals and promote the transfer rate of coke precursors, greatly lessening the occurrence of the subsequent coking reactions during the whole GTA process.
Co-reporter:Weiyin Xiao, Fei Wang and Guomin Xiao
RSC Advances 2015 vol. 5(Issue 78) pp:63697-63704
Publication Date(Web):14 Jul 2015
DOI:10.1039/C5RA07593A
A series of hierarchical HZSM-5 zeolites were prepared by post-synthesis modification of conventional bulk crystals of HZSM-5 zeolite with sodium hydroxide (NaOH) solution at different concentrations. These micro–mesoporous composite molecular sieves were characterized by powder X-ray diffraction, transmission electron microscopy, nitrogen adsorption, Fourier transform infrared (FT-IR) spectroscopy techniques and pyridine FT-IR to investigate the changes in crystallinity, acidity, morphology and textural property of HZSM-5 zeolite before and after alkaline treatment. The catalytic performances of these hierarchical HZSM-5 zeolites were evaluated by the aromatization of glycerol with methanol as the solvent, which was a promising route for converting renewable glycerol and methanol into high value aromatics. Substantial mesoporosity with sizes centered at around 4 nm could be generated for HZSM-5 zeolites after treatment with mild NaOH solution (≤0.4 M), coupled with improved retained microporosity, resulting in great improvements in catalytic lifetime and selectivity to benzene, toluene and xylene (BTX) aromatics during the reaction of glycerol to aromatics. Although the larger mesopore surface areas were achieved when treated with NaOH concentrations that were higher than 0.5 M, the HZSM-5 structure was partly damaged, leading to the reduction of catalytic lifetime and selectivity to BTX aromatics. The HZSM-5 treated with 0.3 M NaOH solution was found to be the optimum catalyst for the transformation of glycerol/methanol to aromatics, producing a nearly two-fold increase in BTX aromatics (carbon yields of 25.18%) and three-fold improvement in catalyst lifetime (12.5 h) when compared to the parent microporous HZSM-5 (13.9% carbon yields of BTX aromatics and catalyst lifetime of 4 h). These improved catalytic performances are mainly attributed to the optimized bimodal micro–mesoporous HZSM-5 zeolite during the alkali treatment, which retained sufficient micropores that have the capacity for aromatization and also more mesopores were created that would shorten the average diffusion path lengths, increase the accessibility to the acid sites and facilitate the transportation of large molecules, e.g., glycerol and carbon precursors, during the aromatization of glycerol.
Co-reporter:Fufeng Cai; Wei Zhu; Yanbin Wang; Tongzhen Wang
Journal of Chemical & Engineering Data 2015 Volume 60(Issue 6) pp:1776-1780
Publication Date(Web):May 13, 2015
DOI:10.1021/je501170h
In this work, the ability of ionic liquids (ILs) 1,3-dimethylimidazolium dimethylphosphate ([MMIM][DMP]), 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM][DEP]), and 1-butyl-3-methylimidazolium dibutylphosphate ([BMIM][DBP]) as alternative solvents used in liquid removal of toluene from its combination with heptane was studied. The liquid–liquid equilibrium (LLE) data in relation to ternary systems {toluene + heptane + [MMIM][DMP], [EMIM][DEP], or [BMIM][DBP]} calibrated at T = 298.2 K and atmospheric pressure. The LLE results studied in relation to ternary systems were fitted by the thermodynamic nonrandom two-liquid (NRTL) model. The toluene solute distribution ratios and toluene/heptane selectivities, derived from the experimental LLE data, were compiled and analyzed to determine the extraction capacity of the studied ILs.
Co-reporter:Fufeng Cai, Wei Zhu, Jessica Juweriah Ibrahim, Guomin Xiao
The Journal of Chemical Thermodynamics 2015 Volume 89() pp:35-40
Publication Date(Web):October 2015
DOI:10.1016/j.jct.2015.04.033
•[A336][SCN] was studied as a solvent to extract polyhydric alcohols from water.•LLE data for ternary systems were determined at T = 303.2 K and atmospheric pressure.•The NRTL model was applied to fit the LLE data with a good accuracy.•Selectivity and solute distribution ratio were obtained and compared with literature.•[A336][SCN] was a promising solvent to separate polyhydric alcohols and water.This work demonstrated the possibility of hydrophobic ionic liquid tricaprylmethylammonium thiocyanate ([A336][SCN]) as a solvent in the separation by extraction of polyhydric alcohols from their mixtures with water. The knowledge of (liquid + liquid) equilibrium (LLE) of these mixtures is essential for the design of the extraction process. For this reason, the LLE data of the ternary systems {[A336][SCN] + water + glycerol, or ethylene glycol, or 1,2-propanediol, or 1,3-propanediol} were determined at T = 303.2 K and atmospheric pressure. The reliability of the tie-lines data was ascertained by applying the Othmer–Tobias equation, and the non-random two liquid (NRTL) model used to fit the experimental LLE data. The effectiveness of the extraction of polyhydric alcohols from water was evaluated using the solute distribution ratio and the selectivity. The extraction capability of [A336][SCN] was compared with that of other ILs. The results indicated that the [A336][SCN] was suitable for use as a solvent in (liquid + liquid) extraction of polyhydric alcohols from water.
Co-reporter:Fufeng Cai, Min Zhao, Yuan Wang, Fei Wang, Guomin Xiao
The Journal of Chemical Thermodynamics 2015 Volume 81() pp:177-183
Publication Date(Web):February 2015
DOI:10.1016/j.jct.2014.09.019
•Phosphoric-based ILs were studied as solvents to extract ethanol from hexane.•LLE data for ternary systems with miscibility gap were presented.•The NRTL model can correlate the experimental LLE data with a good accuracy.•[MMIM][DMP] was a promising solvent for the separation of ethanol and hexane.Ethanol and hexane mixtures are present in industrial processes producing oxygenated additives for unleaded gasoline. The separation of ethanol and hexane is important but challenging due to the formation of an azeotropic mixture. This research focuses on the study of phosphoric-based ionic liquids (ILs) as green solvents for the separation of ethanol from hexane in a liquid extraction process. The knowledge of the (liquid + liquid) equilibrium (LLE) of this mixture is essential for the design of the extraction separation technique. Hence, the experimental determination of the LLE data for the ternary system {ethanol + hexane + 1,3-dimethylimidazolium dimethylphosphate ([MMIM][DMP])}, {ethanol + hexane + 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM][DEP])} and {ethanol + hexane + 1-butyl-3-methylimidazolium dibutylphosphate ([BMIM][DBP])} at T = 303.2 K and atmospheric pressure was carried out. The reliability of the experimental LLE data was confirmed by applying the Othmer–Tobias and Hand equations, and the NRTL model was used to correlate the experimental results for the studied ternary system. The solute distribution ratio and selectivity, derived from the experimental LLE data, were calculated and analyzed evaluate the capacity of the investigated ILs as solvents in liquid extraction process. This capacity was also compared with that of other ILs. The experimental results show that the studied ILs can be suitable solvents in a (liquid + liquid) extraction for the separation of azeotropic mixtures of ethanol and hexane.Potential solvent for the separation of ethanol and hexane in (liquid + liquid) extraction.
Co-reporter:Fufeng Cai; Jessica Juweriah Ibrahim; Lei Niu; Wei Xu
Journal of Chemical & Engineering Data 2015 Volume 60(Issue 1) pp:57-64
Publication Date(Web):December 4, 2014
DOI:10.1021/je500672d
The azeotrope methanol and methyl acetate is involved in the industrial manufacturing process of vinyl alcohol which is made from vinyl acetate by alcoholysis with methanol. This work focused on a study of ionic liquid as a solvent in the extraction separation for this azeotropic mixture. The knowledge of liquid–liquid equilibrium (LLE) is essential for the design of the extraction separation process. For this reason, LLE data for the ternary system {methanol + methyl acetate + 1,3-dimethylimidazolium dimethylphosphate ([MMIM][DMP])} were measured at the temperatures T = (298.2, 313.2, and 328.2) K and atmospheric pressure. The consistency of the experimental LLE data was ascertained by using the Othmer-Tobias and Hand equations. Additionally, the experimental LLE data were compared with the correlated values obtained by means of the nonrandom two liquid (NRTL) model. The solute distribution ratios and selectivity values, derived from the experimental LLE data, were calculated and analyzed in order to evaluate the efficiency as a solvent in liquid extraction process. The experimental results show that [MMIM][DMP] can be used as a potential solvent for the separation of methanol and methyl acetate in the liquid–liquid extraction.
Co-reporter:Minghao Zhou, Lufei Tian, Lei Niu, Cong Li, Guomin Xiao, Rui Xiao
Fuel Processing Technology 2014 Volume 126() pp:12-18
Publication Date(Web):October 2014
DOI:10.1016/j.fuproc.2014.04.015
•NiMo/CNT catalysts possess high catalytic activity for the hydrogenation reaction.•Upgrading of bio-oil was carried out in mild conditions.•Synergistic effect was observed in the hydrogenation process of synthetic bio-oil.•The pH value of bio-oil increased from 2.92 to 3.68 after upgrading.•The H element content increased from 8.40 wt.% to 11.26 wt.% after upgrading.A series of non-sulfided nickel-based catalysts with HNO3-pretreated CNTs as support ((x1 + x2) wt.% NiMo/CNTs, xi represents the Ni or Mo loading amount) were synthesized, and evaluated for the hydrogenation of bio-oil model compounds (acetic acid, furfural and hydroxyacetone) and raw bio-oil. Acetic acid was chosen for the initial screening of catalysts. Results showed that reduced (10 + 10) wt.% NiMo/CNT catalyst exhibited the highest activity. Hydrogenation of other model compounds and raw bio-oil was then carried out over reduced (10 + 10) wt.% NiMo/CNT catalyst. A synergistic effect was observed in the hydrogenation process of a model compound mixture, which led to the aldol condensation between furfural and hydroxyacetone to give a C8 compound, which could give most valuable hydrocarbon after deep hydrogenation. After the upgrading process, both the pH and the hydrogen content of bio-oil increased, and the oxygen content decreased, which were all desirable for the further application of upgraded bio-oil.
Co-reporter:Fufeng Cai, Jessica Juweriah Ibrahim, Lijing Gao, Ruiping Wei, Guomin Xiao
Fluid Phase Equilibria 2014 Volume 382() pp:254-259
Publication Date(Web):25 November 2014
DOI:10.1016/j.fluid.2014.09.016
•LLE data for methanol + DMC + phosphoric-based ILs were measured in this work.•LLE data for ternary systems with miscibility gap were presented.•The NRTL model can correlate the experimental LLE data with a good accuracy.•The extraction capacity for the ILs follows this order: [MMIM][DMP] > [EMIM][DEP].Methanol and dimethyl carbonate (DMC) mixture is present in the industrial manufacturing process of DMC, which is made from the catalytic oxidative carbonylation of methanol. The separation of methanol and DMC is important but difficult due to the formation of an azeotropic mixture. This work has been focused on a study of phosphoric-based ionic liquids (ILs) as green solvents for the separation of methanol and DMC in the extraction process. The knowledge of liquid–liquid equilibrium (LLE) of this mixture is essential for the design of the extraction separation process. For this reason, LLE data for the ternary systems {methanol + DMC + 1-methyl-3-methylimidazolium dimethylphosphate ([MMIM][DMP])} and {methanol + DMC + 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM][DEP])} were measured at T = (298.2 and 313.2) K and atmospheric pressure. The solute distribution ratio and selectivity of the methanol, derived from the tie-lines data, were calculated and analyzed in order to evaluate the capacity of the studied ILs as solvents in liquid extraction process. The experimental results show that the values of selectivity for the studied ILs follow this order: [MMIM][DMP] > [EMIM][DEP]. Finally, the experimental LLE data for the studied ternary systems were compared with the calculated values obtained by means of the non-random two liquid (NRTL) model. The NRTL model was verified to accurately correlate the experimental LLE data.LLE data for methanol + DMC + phosphoric-based ILs were determined.
Co-reporter:Lei Niu;Zunshan Li;Feng Jiang
Reaction Kinetics, Mechanisms and Catalysis 2014 Volume 112( Issue 1) pp:199-208
Publication Date(Web):2014 June
DOI:10.1007/s11144-014-0697-z
Vapor phase ortho-selective methylation of m-cresol with methanol has been carried out over the catalyst of Fe, Si, Al and K oxides in a fixed-bed, down-flow reactor at 573–673 K. Catalyst characterization has been carried out by XRD, BET and SEM. 2,3,6-Trimethylphenol was found to be the major product derived with very little 2,3-xylenol and 2,5-xylenol. The effect of the K2O content of the catalyst, reaction temperature, reactant molar ratio and LHSV on the methylation of m-cresol with methanol was investigated. When the formation of the catalyst was fixed at Fe2O3:SiO2:Al2O3:K2O = 100:5:2:0.9, under a reaction condition of 653 K reaction temperature, 7:1 methanol to m-cresol molar ratio and 1.3 h−1 LHSV, the maximum yield of 97.2 % was obtained for 2,3,6-trimethylphenol, and the yield kept around 97 % even after the reaction time of 100 h.
Co-reporter:Lei Niu;Ruiping Wei;Feng Jiang
Reaction Kinetics, Mechanisms and Catalysis 2014 Volume 113( Issue 2) pp:543-556
Publication Date(Web):2014 December
DOI:10.1007/s11144-014-0745-8
A series of dealumination ultrastable Y-type zeolite (DUSY) supported Cu catalysts with different Cu loadings were prepared, characterized and tested in the hydrogenolysis of glycerol. The results showed that DUSY retained the Y zeolite structure and generated abundant of secondary mesoporous, which not only facilitated the 1,2-propanediol (1,2-PDO) to diffuse out the catalyst, but also improved the dispersion of Cu. Cu/DUSY catalyst exhibited single weak acid sites and unique reduced structure of Y type zeolite and resulted in a more concentrated product distribution, primarily 1,2-PDO with few glycols.
Co-reporter:Hongyan Zhu;Minghao Zhou;Zuo Zeng
Korean Journal of Chemical Engineering 2014 Volume 31( Issue 4) pp:593-597
Publication Date(Web):2014 April
DOI:10.1007/s11814-013-0253-y
A series of Cu-Ni-Al hydrotalcites derived oxides with a (Cu+Ni)/Al mole ratio of 3 with varied Cu/Ni mole ratio (from 0.017 to 0.5, with a Cu ratio of 0.0125 to 0.25) were prepared by co-precipitation method, then applied to the hydrogenation of furfural in aqueous. Their catalytic performance for liquid phase hydrogenation of furfural to prepare cyclopentanone was described in detail, considering reaction temperature, catalyst composition, reaction time and so on. The yield of cyclopentanone was influenced by the mole ratio of Cu-Ni-Al based heterogeneous catalyst and depended on the reaction conditions. The yield of cyclopentanone was up to 95.8% when the reaction was carried out under 413 K with H2 pressure of 40 bar for 8 h. The catalysts were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM) and H2 temperature-programmed reduction (H2-TPR).
Co-reporter:Lijing Gao;Wei Xu;Lihua Chen
Journal of Porous Materials 2014 Volume 21( Issue 5) pp:667-675
Publication Date(Web):2014 October
DOI:10.1007/s10934-014-9813-8
In this study, a new kind of solid acid catalyst p-toluenesulfonic acid/MCM-41/ceramic membrane was synthesized by in situ synthesis and impregnation method, which has shown its favorable catalytic activity, as verified in the transesterification and catalyst characterization. The catalyst was characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier-transform infrared spectroscopy. The transesterification of palm oil and methanol results showed that p-toluenesulfonic acid/MCM-41/ceramic membrane had the highest catalytic activity with immersing p-toluenesulfonic acid solution concentration of 0.15 mol/L. Different operation parameters of the transesterification of palm oil with methanol, such as catalyst amount, catalytic mass ratio, reaction time, reaction temperature and methanol/palm oil molar ratio were investigated. Under the optimum conditions of 4 % of fresh catalyst (catalytic mass ratio is 4.37 %), 80 min of reaction time, reaction temperature of 120 °C and methanol to palm oil molar ratio of 12:1, a relatively high fatty acid methyl ester yield of 95.6 % was obtained.
Co-reporter:Wei Xu, Lijing Gao, Songcheng Wang, and Guomin Xiao
Energy & Fuels 2013 Volume 27(Issue 11) pp:6738-6742
Publication Date(Web):October 30, 2013
DOI:10.1021/ef401823z
Transesterification of soybean oil to produce biodiesel was performed in a membrane reactor packed with shaped KF/Ca–Mg–Al hydrotalcite solid base. The microfiltration ceramic membrane (length: 20 cm, inner/outer diameter: 6/10 mm) was used to retain the oil during the transesterification reaction. High quality biodiesel was produced in the fixed bed membrane reactor by coupling heterogeneous alkali catalyzed transesterification and separation process. The response surface methodology (RSM) was employed to evaluate the effects of such factors as reaction temperature, catalyst amount, and circulation velocity on biodiesel production. 70 °C reaction temperature, 0.531 g/cm3 catalyst amount and 3.16 mL/min circulation velocity was found to be the optimum condition, achieving a 0.1820 g/min biodiesel yielding rate during 150 min of circulation time.
Co-reporter:Hu Liu;Baosong Fu;Qianqian Shang
Journal of Applied Polymer Science 2013 Volume 127( Issue 4) pp:3204-3212
Publication Date(Web):
DOI:10.1002/app.37739
Abstract
In this study, vinyl-group modified nanosilicas (mSiO2) were prepared via sol–gel method using vinyltriethoxysilane (VTES) as modifier first, then the novel poly(hydroxylic fluoroacrylate)/mSiO2 nanocomposite was successfully synthesized by in situ solution polymerization of mSiO2 with dodecafluoroheptyl methacrylate (DFHMA), β-hydroxyethyl methacrylate (HEMA), methyl methacrylate (MMA), and butyl acrylate (BA) initiated by 2,2-azobisisobutyronitrile (AIBN) in the co-solvents of ethyl acetate and butyl acetate. The chemical composition and structure of the nanocomposite were characterized by Fourier transform infrared spectrometry (FTIR) and transmission electron microscopy (TEM). TEM observation indicated that mSiO2 nanoparticles obtained a well dispersion in polymeric matrix. Thermogravimetric analysis (TGA) studies revealed that the temperature corresponding to 50% weight loss of the nanocomposite was improved by 21.5°C with the addition of 2.0 wt % mSiO2. The synthesized nanocomposites were applied to use with hexamethylene diisocyanate trimer (HDIT) to prepare polyurethane materials. Tensile test revealed that polyurethane material with mSiO2 content of 2.0 wt % showed an ultimate tensile strength of about 5.19 times higher than that without mSiO2. The polyurethane films displayed surface energy of lower than 25 mN m–1 and high light transmittance. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Co-reporter:Qianqian Shang;Mengyu Wang;Hu Liu;Lijing Gao
Polymer Composites 2013 Volume 34( Issue 1) pp:51-57
Publication Date(Web):
DOI:10.1002/pc.22376
Abstract
A facile and novel strategy was reported on the fabrication of raspberry-like SiO2/polystyrene (SiO2/PS) composite particles by emulsion polymerization in the presence of vinyl-functionalized silica (vinyl-SiO2) particles, which were prepared via a one-step sol–gel process using vinyltriethoxysilane as the precursor. The submicron vinyl-SiO2 particles were used as the core, and nanosized PS particles were then adsorbed onto the vinyl-SiO2 particles to form raspberry-like composite particles during the polymerization process. The composition, morphology, and structure of the vinyl-SiO2 particles and the SiO2/PS hybrid particles were characterized by thermogravimetric analysis, nuclear magnetic resonance, Fourier transform infrared spectroscopy, transmission electron microscopy, and scanning electron microscopy. Superhydrophobic surface can be constructed by directly depositing the raspberry-like SiO2/PS composite particles on glass substrate, and the water contact angle can be adjusted by the styrene/SiO2 weight ratio. In addition, the superhydrophobic film possessed a strong adhesive force to pin water droplet on the surface even when the film was turned upside down. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers
Co-reporter:Feng Jiang;Wei Xu;Lei Niu
Catalysis Letters 2013 Volume 143( Issue 11) pp:1200-1206
Publication Date(Web):2013 November
DOI:10.1007/s10562-013-1058-7
Bulk and silica supported vanadium–chromium oxide (VCrO) catalysts with different VCrO loadings were prepared and their catalytic activity was evaluated in the ammoxidation of 3-picoline to nicotinonitrile. The silica supported catalysts had larger surface area and different active phases compared with the bulk catalyst. These differences varied the acidity and reducibility of the catalysts and finally resulted in distinction in catalytic properties. The high selectivity was confirmed to be related to the low surface density of acid sites, and the high activity coincided with the high surface area and reducibility.
Co-reporter:Hu Liu;Baosong Fu;Yi Li;Qianqian Shang
Journal of Coatings Technology and Research 2013 Volume 10( Issue 3) pp:361-369
Publication Date(Web):2013 May
DOI:10.1007/s11998-012-9452-4
The novel polymethylsiloxane grafted by fluorocarbon side chains was synthesized via hydrosilylation reaction of polymethylhydrosiloxane (PMHS) with 2,2,3,4,4,4-hexafluorobutyl acrylate (HFBA) in the presence of Karstedt’s catalyst. The reaction factors of reaction temperature, reaction time, catalyst dosage, solvent dosage, and molar ratio of the reactants were investigated through orthogonal experiments. Under optimal conditions, the grafting ratio of HFBA to PMHS reached 91.6%. The structure of the grafted polymer was characterized by FTIR and 1H NMR spectra. The synthesized polymer was incorporated into two-component polyurethane coating formulations as an additive to prepare antigraffiti coatings. After curing, the contact angle measurement was performed and the results showed that surface free energy of the coating film decreased dramatically from 30.7 to 21.4 mJ/m2. The inks of permanent markers cannot spread readily on the coating film and can be removed easily, indicating that the incorporation of the synthesized polymer endowed the coating with admirable antigraffiti performance. XPS analysis revealed that atomic concentrations of silicon and fluorine near the surface (about 10 nm) were much higher than deeper within the film (about 100 nm), suggesting that these two elements had a strong migration tendency toward the coating–air interface. AFM measurement showed that the inclusion of synthesized polymer in coating did not affect the surface roughness of the film.
Co-reporter:Hu Liu;Lijing Gao;Qianqian Shang
Journal of Coatings Technology and Research 2013 Volume 10( Issue 6) pp:775-784
Publication Date(Web):2013 November
DOI:10.1007/s11998-013-9507-1
A type of antigraffiti polyurethane clearcoat was prepared and characterized. Polymethylsiloxane grafted by fluorocarbon side chains (PSF) was first synthesized through hydrosilylation of polymethylhydrosiloxane with dodecafluoroheptyl acrylate. Hydroxyl fluoroacrylate resins with different hydroxyl contents were synthesized via free radical-initiated solution polymerization and further applied to prepare polyurethane clearcoats. The synthesized polymers were structurally characterized by using Fourier transform infrared and 1H nuclear magnetic resonance. The prepared polyurethane clearcoats underwent contact angle measurement, dynamic thermal mechanical analysis, nanoscratch experiments, and atomic force microscopy. The results reveal that low surface energy, high crosslink density, low coefficient of friction, and low roughness were jointly beneficial to antigraffiti properties. Antigraffiti testing was carried out on the clearcoat with 8.0 wt% PSF and 2.0 wt% active silicone fluid, and this clearcoat showed high resistance to acrylic spray paint, permanent markers, and other graffiti materials.
Co-reporter:Qianqian Shang;Mengyu Wang;Hu Liu
Journal of Coatings Technology and Research 2013 Volume 10( Issue 4) pp:465-473
Publication Date(Web):2013 July
DOI:10.1007/s11998-012-9465-z
Water repellent SiO2 particulate coatings were prepared by a one-step introduction of vinyl groups on the coating surface. Rough surface structure and low surface energy could be directly obtained. Vinyl functionalized SiO2 (vinyl-SiO2) spheres with average diameter of 500 nm were first synthesized by a sol–gel method in aqueous solution using vinyltriethoxysilane as the precursor. The multilayer SiO2 coating fabricated by dip-coating method was highly hydrophobic with a water contact angle of 145.7° ± 2.3°. The superhydrophobic SiO2 coating with a water contact angle up to 158° ± 1.7° was prepared by spraying an alcohol mixture suspension of the vinyl-SiO2 spheres on the glass substrate. In addition, the superhydrophobic SiO2 coating demonstrated good stability under the acidic condition. However, it lost its hydrophobicity above 200°C because of the oxidation and degradation of vinyl groups.
Co-reporter:Yang Xiao, Lijing Gao, Guomin Xiao, Baosong Fu, and Lei Niu
Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 37) pp:11860-11865
Publication Date(Web):March 5, 2012
DOI:10.1021/ie202312z
A 500 h endurance test of continuous catalytic transesterification to biodiesel was conducted in a bench-scale fixed-bed reactor. A designed cylinder shape of KF/Ca–Mg–Al hydrotalcite catalyst was stable through the test with high catalytic activity and mechanical strength, converting palm oil to biodiesel with a conversion of more than 95%. Conditions effects on transesterification under relative high pressure (1.0 MPa) were investigated and a one-dimensional heterogeneous model of a fixed-bed reactor was developed to describe the reaction-mass transfer behaviors of continuous catalytic transesterification in a bench-scale fixed-bed reactor. With the given reactor size, optimum conditions were proposed as a LHSV (liquid hourly space velocity) of 0.76–0.25 h–1, molar ratio of methanol-to-oil of 9.16–13.7, and temperature of 338–347 K.
Co-reporter:Qianqian Shang;Baosong Fu;Hu Liu
Journal of Coatings Technology and Research 2012 Volume 9( Issue 5) pp:589-595
Publication Date(Web):2012 September
DOI:10.1007/s11998-012-9394-x
A fluorine–silicon polymer of poly(styrene-co-1H,1H,2H,2H-perfluorooctyl methacrylate-co-vinyltriethoxysilane) (PSFV) was synthesized by bulk polymerization, and superhydrophobic surfaces were subsequently fabricated utilizing phase separation technique in one step by casting PSFV copolymer solution under ambient atmosphere. The PSFV copolymer was dissolved in tetrahydrofuran (THF), and then ethanol was added into the solution to induce phase separation. The surface morphologies of the copolymer films were controlled by the degree of phase separation, which could be tuned easily by the ethanol/THF volume ratio and the solution’s initial concentration. Scanning electron microscopy observations indicated that the superhydrophobic copolymer film had a rough surface with a binary hierarchical structure. A brief explanation of the formation of the special microstructure was put forward. The water contact angle and sliding angle of the superhydrophobic PSFV surface were measured as 162° and 4°, respectively. The simplicity of the operation’s process might make the superhydrophobic surface potentially useful in a variety of applications.
Co-reporter:Tingfeng Yan;Mei Hong;Lei Niu;Feng Jiang
Research on Chemical Intermediates 2012 Volume 38( Issue 8) pp:1839-1846
Publication Date(Web):2012 October
DOI:10.1007/s11164-012-0507-z
Oxidation of 2-methylnaphthalene (2-MN) with aqueous hydrogen peroxide was conducted in acetic acid. The epoxidation pathway was investigated by increasing the CH3CO3H content and adding manganese(II) naphthenate (MnPc) as catalyst. 2-Methyl-1,4-naphthoquinone was obtained in 75.6% conversion and with 80.0% selectivity under the latter conditions. A probable mechanism in which MnPc catalyzes the oxidation of 2-MN by hydrogen peroxide in acetic acid is proposed.
Co-reporter:Minghao Zhou;Mei Hong
Research on Chemical Intermediates 2012 Volume 38( Issue 9) pp:2237-2243
Publication Date(Web):2012 November
DOI:10.1007/s11164-012-0540-y
(6R)- and (6S)-5,6,7,8-tetrahydrofolic acid were resolved by reversed-phase HPLC on a C-18 column with hydroxypropyl-β-cyclodextrin (HP-β-CD) in the mobile phase. As the concentration of HP-β-CD increased from 0 to 45 mM, resolution increased and retention times decreased dramatically. The influence of different mobile phase pH, column temperature, and some other factors were evaluated, and we obtained the optimal HPLC separation conditions.
Co-reporter:Y. Tong;L. Gao;G. Xiao;X. Pan
Chemical Engineering & Technology 2011 Volume 34( Issue 2) pp:241-248
Publication Date(Web):
DOI:10.1002/ceat.201000379
Abstract
Supercritical CO2 extraction with a static modifier was applied to extract chlorophyll a from Spirulina platensis. The effects of the process were investigated by single-factor and response surface analysis experiments. The optimal process parameters for supercritical CO2 extraction were determined to be: ethanol/water as the modifier, 40 vol.-% water content in the modifier, 21.2 mL modifier volume, 1 h static soaking time, 2 h dynamic extraction time, 48.7 MPa extraction pressure, 326.4 K extraction temperature, and 10 g min–1 CO2 flow rate. The optimized chlorophyll a extraction yield was 6.84 mg g–1. A comparison of the experimental results suggested that the yield of chlorophyll a by supercritical CO2 extraction with modifier was higher than that obtained by conventional solvent extraction.
Co-reporter:Qianqian Shang;Lijing Gao;Hu Liu
Journal of Sol-Gel Science and Technology 2011 Volume 59( Issue 2) pp:
Publication Date(Web):2011 August
DOI:10.1007/s10971-011-2507-7
A superhydrophobic silica film has been fabricated by a facile method, which combines the co-sedimentation of dual-sized polystyrene (PS) spheres and the infiltration of a silica sol. The scanning electron microscopy (SEM) observations indicate that the as-prepared silica surface has a hierarchical micro/nano-structure. The micrometer-sized hollow silica particle with nanometer-sized holes on its surface was created by removing the organic polymer at high temperature. After chemically modified by a layer of dodecafluoroheptyl-methyl-dimethoxysilane (DFMS), the silica film has a water contact angle up to 156.4°, showing excellent superhydrophobic property. The present method may enhance widespread application of superhydrophobic film because of its simplicity and cheapness.
Co-reporter:Yang Xiao, Lijing Gao, Guomin Xiao, and Jianhua Lv
Energy & Fuels 2010 Volume 24(Issue 11) pp:5829-5833
Publication Date(Web):October 12, 2010
DOI:10.1021/ef100966t
Kinetics of the transesterification reaction catalyzed by solid base in a fixed-bed reactor was studied in this paper. The transesterification reaction between palm oil and methanol was catalyzed by KF/Ca−Mg−Al hydrotalcite solid base, which made it a complicated liquid−liquid−solid heterogeneous reaction. Isopropyl ether was used to obtain a homogeneous reactant system, and then liquid−liquid mass-transfer limitations were eliminated. Experimental results showed that, when the feed rate was faster than 0.3 mL/min, liquid−solid external diffusion mass-transfer limitations were negligible and, when the diameter of the catalyst particle was not larger than 0.18 mm, liquid−solid internal diffusion mass-transfer limitations could be neglected as well. Then, intrinsic reaction rates of this transesterification under different space velocities, temperatures, and concentrations were measured in a fixed-bed integral reactor. An intrinsic kinetic model was developed on the basis of the Eley−Rideal mechanism according to the experimental data, which indicated a new mechanism of the transesterification reaction catalyzed by solid base. The transesterification reaction occurred between methanol adsorbed on solid base active sites and glyceride from the liquid phase. The surface reaction of triglyceride with adsorbed methanol was assumed to be rate-determining. The model calculation agreed well with experimental data. Regression of experimental data indicated that the transesterification reaction was an endothermic reaction and the activation energy was 111.6 kJ/mol.
Co-reporter:Lijing Gao, Guangyuan Teng, Jianhua Lv and Guomin Xiao
Energy & Fuels 2010 Volume 24(Issue 1) pp:646-651
Publication Date(Web):November 17, 2009
DOI:10.1021/ef900800d
A series of solid base catalysts, KF/Ca−Mg−Al hydrotalcite (KF mass ratio of 100%) with different cation ratios, were prepared and studied in this research. Effects of the cation ratio of the Ca−Mg−Al hydrotalcite and the methanol/oil molar ratios on the fatty acid methanol ester (FAME) yield of the transesterification of palm oil with methanol were investigated. The results of the transesterification reactions showed that all of these kinds of catalysts had a very high activity for the biodiesel yields, obtaining 90% or more with 10 min of reaction under the conditions of 338 K, 12:1 methanol/oil molar ratio, and 5% (wt/wt oil) catalyst amount. In addition, the FAME yield could reach 99.6% in 10 min catalyzed by the optimal catalyst KF/Ca−Mg−Al hydrotalcite (2.2:0.8:1 Ca/Mg/Al; KF mass ratio of 100%), under the same reaction conditions as above.
Co-reporter:J. Lv ;G. Xiao
Chemical Engineering & Technology 2010 Volume 33( Issue 12) pp:2051-2058
Publication Date(Web):
DOI:10.1002/ceat.201000239
Abstract
Poly(vinyl alcohol)/polyacrylonitrile blend membranes were prepared to separate pyridine/water mixtures by pervaporation. The membranes were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The effects of membrane composition, feed pyridine concentration, operating temperature, downstream pressure and ultrasound irradiation on the separation process were evaluated. The experimental results indicated that with increasing PVA mass ratio and operating temperature the permeate flux increased but the separation factor decreased, while with increasing feed concentration and downstream pressure the separation factor increased and the permeate flux decreased. It was observed that Ultrasound irradiation enhanced the permeate flux.
Co-reporter:Guangyuan Teng;Lijing Gao;Hu Liu
Applied Biochemistry and Biotechnology 2010 Volume 162( Issue 6) pp:1725-1736
Publication Date(Web):2010 November
DOI:10.1007/s12010-010-8953-9
This paper discusses the synthesis of biodiesel catalyzed by solid base of K2CO3/HT using Jatropha curcas oil as feedstock. Mg–Al hydrotalcite was prepared using co-precipitation methods, in which the molar ratio of Mg to Al was 3:1. After calcined at 600 °C for 3 h, the Mg–Al hydrotalcite and K2CO3 were grinded and mixed according to certain mass ratios, in which some water was added. The mixture was dried at 65 °C, and after that it was calcined at 600 °C for 3 h. Then, this Mg–Al hydrotalcite loaded with potassium carbonate was obtained and used as catalyst in the experiments. Analyses of XRD and SEM characterizations for catalyst showed the metal oxides formed in the process of calcination brought about excellent catalysis effect. In order to achieve the optimal technical reaction condition, five impact factors were also investigated in the experiments, which were mass ratio, molar ratio, reaction temperature, catalyst amount and reaction time. Under the best condition, the biodiesel yield could reach up to 96%.
Co-reporter:Baosong Fu, Lijing Gao, Lei Niu, Reiping Wei and Guomin Xiao
Energy & Fuels 2009 Volume 23(Issue 1) pp:569
Publication Date(Web):December 4, 2008
DOI:10.1021/ef800751z
The solid superacid catalyst SO42−/ZrO2 was prepared by impregnation and characterized by infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction. Their performances were evaluated by the transesterification reaction of waste cooking oil (WCO) with methanol. The influence of the load ratio of SO42−/ZrO2, molar ratio of methanol/waste cooking oil, catalyst amount, reaction temperature, and reaction time on biodiesel yield was investigated. Under a condition of methanol/WCO molar ratio of 9:1, a catalyst amount of 3 wt %, reaction time of 4 h, and reaction temperature of 120 °C, 93.6% of biodiesel yield was obtained.
Co-reporter:Guangyuan Teng, Lijing Gao, Guomin Xiao and Hu Liu
Energy & Fuels 2009 Volume 23(Issue 9) pp:4630-4634
Publication Date(Web):July 20, 2009
DOI:10.1021/ef9003736
Synthesis of biodiesel from soybean oil over solid base catalyst was investigated in this paper. In process of catalyst preparation, potassium fluoride was used as alkaline metal salt to load onto γ-Al2O3. Over this basic catalyst, transesterification reactions were carried out to prepare biodiesel using soybean oil and methanol as feedstock. According to experiments, the best reaction conditions were gotten as followed: load ratio was 72.68% (by weight), molar ratio was 12:1 (methanol/oil), reaction temperature was 338 K, mass of catalyst was 2% of oil (by weight), and reaction time was 3 h. Yield of biodiesel exceeds 99%. With X-ray diffraction (XRD) and DSC-TGA characterization, it was proved that new crystal phase synthesized by calcinations showed its favorable effect to the transesterification reaction.
Co-reporter:Lijing Gao, Bo Xu, Guomin Xiao and Jianhua Lv
Energy & Fuels 2008 Volume 22(Issue 5) pp:3531
Publication Date(Web):August 26, 2008
DOI:10.1021/ef800340w
The KF/hydrotalcite (HT) solid base catalysts were prepared by impregnation and characterized by X-ray diffraction. Biodiesel can be obtained from transesterification of palm oil with methanol over the KF/HT catalysts. The effect factors, such as KF/HT load ratio, methanol/oil molar ratio, catalyst amount, reaction time, and reaction temperature, were investigated. When the reaction was carried out at 338 K, with palm oil/methanol molar ratio of 12:1, reaction time of 3 h, and catalyst amount of 3 wt %, the yield of fatty acid methyl esters can reach 85%, and when the reaction time prolonged to 5 h, the yield can become 92%.
Co-reporter:Xu Bo, Xiao Guomin, Cui Lingfeng, Wei Ruiping and Gao Lijing
Energy & Fuels 2007 Volume 21(Issue 6) pp:3109
Publication Date(Web):November 3, 2007
DOI:10.1021/ef7005035
The KF/Al2O3 catalysts were prepared by an impregnation method and characterized by X-ray diffraction and thermogravimetric analysis. Their catalytic performances were evaluated in the transesterification of palm oil with methanol. The effects of the load ratio of KF to Al2O3, molar ratio of methanol/oil, amount of catalyst, reaction time, and temperature on product yields were investigated. The catalytic behavior was examined in relation to physiochemical properties of the catalysts.
Co-reporter:Cui Lingfeng, Xiao Guomin, Xu Bo and Teng Guangyuan
Energy & Fuels 2007 Volume 21(Issue 6) pp:3740-3743
Publication Date(Web):October 20, 2007
DOI:10.1021/ef700405e
Alkyl esters of long chain fatty acid are called biodiesel. These esters can be obtained from the transesterification of triglycerides with methanol/ethanol. This work investigated the possibility of using KF/γ-Al2O3 as heterogeneous catalysts for the transesterification of cottonseed oil with methanol. The operation variables used were methanol/oil molar ratio (6:1–18:1), catalyst concentration (1–5 wt %), temperature (50–68 °C), and catalyst type. The biodiesel with the best properties was obtained using a methanol/oil molar ratio of 12:1, catalyst (4%), and 65 °C temperature with the catalyst KF/γ-Al2O3. The strongest basic sites (superbasic) promote the transesterification reaction also at very low temperature (65 °C), while the basic sites of medium strength require higher temperatures to promote the same reaction.
Co-reporter:Lijing Gao, Guangyuan Teng, Guomin Xiao, Ruiping Wei
Biomass and Bioenergy (September 2010) Volume 34(Issue 9) pp:1283-1288
Publication Date(Web):September 2010
DOI:10.1016/j.biombioe.2010.03.023
Co-reporter:Fei Wang, Ma-xi Zhou, Xing-hui Yang, Li-jing Gao, Guo-min Xiao
Molecular Catalysis (May 2017) Volume 432() pp:144-154
Publication Date(Web):1 May 2017
DOI:10.1016/j.mcat.2017.01.017
•Deoxygenation and dehydration resulted in a superior quality in liquid products.•Smaller intramesopores exhibit better BTX yields and slower carbon deposition rate.•The reaction route during the GTA procedure was changed over hierarchical HZSM-5.One-step aromatization of glycerol to value-added aromatics is a very promising way not only owing to the growing byproduct of glycerol in biodiesel manufacturing but also due to the imperious demands to provide a sustainable route for aromatics production to alleviate the dependence on fossil fuels. Different hierarchical HZSM-5 catalysts with diverse sizes of intramesoporosity and similar size of microporosity are prepared by desilication with different alkali. The occurrence of deoxygenation and dehydration reactions among the GTA process brought about a noticeable drop in the oxygen content of the organic products and as a consequence, resulted in a superior quality in liquid products, in which aromatics, such as benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene, et al., were the major components. Liquid route during the GTA reaction was suppressed while the gas route was enhanced over the desilicated HZSM-5 samples, leading to the increment of BTX light aromatics yields and reduction of the heavier aromatics yields (trimethylbenzene, tetramethylbenzene). It was found that smaller intramesopores (3–5 nm) together with well-preservation of parent HZSM-5 microporosity exhibited better shape-selective BTX yields and slower carbon deposition rate during the GTA procedure than larger ones (6–16 nm).Download full-size imageLiquid route during the GTA reaction was suppressed while the gas route was enhanced over the desilicated HZSM-5 samples, leading to the increment of BTX light aromatics yields and reduction of the heavier aromatics yields (trimethylbenzene, tetramethylbenzene).
Co-reporter:Lian Wang, Qun Liu, Minghao Zhou, Guomin Xiao
Journal of Natural Gas Chemistry (January 2012) Volume 21(Issue 1) pp:25-28
Publication Date(Web):1 January 2012
DOI:10.1016/S1003-9953(11)60328-9
Zirconia-loaded sulfuric acid (SO42−/ZrO2) catalysts were prepared by impregnation method, molded by punch tablet machine and characterized by X-ray diffraction. SO42−/ZrO2 catalyst was used to obtain glycerol triacetate (GTA) directly from glycerin. The effect of some factors, such as different temperatures of calcination and catalysts molded or not, on the reusable times of catalysts and the yield of GTA were investigated. The optimum reaction conditions were shown as follows: the reaction temperature was 403 K; the reaction time continued for 8 h; the amount of molded catalysts was 5 wt% of glycerin and the molar ratio of glycerin to acetic acid was 1:8. The yield of GTA was 97.93% under the optimum condition.
Co-reporter:Xianghai Song, Yuanfeng Wu, Fufeng Cai, Donghui Pan, Guomin Xiao
Applied Catalysis A: General (25 February 2017) Volume 532() pp:77-85
Publication Date(Web):25 February 2017
DOI:10.1016/j.apcata.2016.12.019
Co-reporter:Fei Wang, Weiyin Xiao, Lijing Gao and Guomin Xiao
Catalysis Science & Technology (2011-Present) 2016 - vol. 6(Issue 9) pp:NaN3086-3086
Publication Date(Web):2015/11/26
DOI:10.1039/C5CY01651G
A series of ZnO/HZSM-5 catalysts were prepared by atomic layer deposition (ALD) with different cycle numbers and tested for methanol to aromatics (MTA) reactions. The growth rate of Zn content monotonically decreases with increasing number of deposition cycles due to the “half-self-limiting” ALD-type growth mode for ZnO on HZSM-5 zeolite, in which the density of the regenerated reactive –OH sites in the HZSM-5 substrates was less than that of the consumed –OH sites in one cycle. The deposited ZnO existed as small nanocrystallites upon low ALD cycles. However, as the number of ALD cycles exceeds a certain value, the resulting ZnO grown on the HZSM-5 substrate exists in the form of a continuous coating with corrugated surfaces, which could effectively prevent damage to the HZSM-5 framework caused by exposure of the zeolite skeleton to steam during the reaction and regeneration processes. The ZnO/HZSM-5 catalyst treated with 40 ALD cycles was proved to be the optimum catalyst for MTA reactions, producing a nearly twofold increase in BTX aromatics (carbon yield of 60.3%) than the parent HZSM-5 (28.3% carbon yield of BTX aromatics). The catalyst prepared by ALD not only is more effective for the aromatization of methanol but also shows a more stable performance in the MTA process than that prepared by conventional methods (i.e. IWI and IE) with a comparable amount of Zn content. This better performance could be ascribed to the synergetic effect that occurred between the multinuclear oxygenated zinc sites and (ZnOH)+ sites formed during the ALD process, which would boost the transformation of inert low alkanes to aromatics.
Co-reporter:Fufeng Cai, Wei Zhu and Guomin Xiao
Catalysis Science & Technology (2011-Present) 2016 - vol. 6(Issue 13) pp:NaN4900-4900
Publication Date(Web):2016/02/29
DOI:10.1039/C6CY00085A
In this work, ZrO2-promoted Cu–Al2O3 catalysts prepared by the co-precipitation method were used for the hydrogenolysis of glycerol to 1,2-propanediol in a fixed-bed reactor. These catalysts were fully characterized by BET, ICP, N2O chemisorption, XRD, H2-TPR, NH3-TPD, XPS, TEM and TGA. The relationship between the catalytic activity and the metal–support interaction was studied in detail. The experimental results showed that the addition of ZrO2 to Cu–Al2O3 could greatly enhance glycerol conversion and 1,2-propanediol selectivity. This improvement was related to the increase in the acidity and Cu dispersion on the catalytic surface. The optimal 20ZrCu–Al2O3 catalyst attained 97.1% glycerol conversion and 95.3% 1,2-propanediol selectivity. Furthermore, the effects of process parameters like solvent, reaction temperature, operating pressure, glycerol concentration and liquid flow rate on glycerol hydrogenolysis together with the catalyst stability were deeply investigated. Compared with the Cu–Al2O3 catalyst, the ZrO2-promoted Cu–Al2O3 catalyst had better stability and potential for practical application, which was likely due to the high Cu dispersion and strong interaction between copper and zirconium species.
Co-reporter:Fufeng Cai and Guomin Xiao
Catalysis Science & Technology (2011-Present) 2016 - vol. 6(Issue 14) pp:NaN5667-5667
Publication Date(Web):2016/04/11
DOI:10.1039/C6CY00116E
In this work, a series of Cu–Co–Al catalysts with different Ce loadings were applied to the hydrogenolysis of glycerol to 1,2-propanediol in a fixed-bed flow reactor. The physicochemical properties of the synthesized catalysts were analyzed using BET, N2O chemisorption, SEM, TEM, XRD, H2-TPR, NH3-TPD and XPS techniques. Systematic characterization demonstrated that the incorporation of Ce into the Cu–Co–Al catalyst could effectively restrain the aggregation of active metal species as well as the growth of metallic particles during calcination and reduction, which resulted in the formation of highly dispersed active metals. Large amounts and superior strength of acid sites were present in the Ce-promoted Cu–Co–Al catalysts, as confirmed by NH3-TPD analysis. The reducible nature of the Cu–Co–Al catalyst greatly increased after the addition of Ce. The higher concentration of acid sites, excellent reducibility and highly dispersed active metals were responsible for the superior catalytic activity of the 8Ce/Cu–Co–Al catalyst and it attained 91.6% glycerol conversion and 92.4% 1,2-propanediol selectivity. In addition, the effects of different process parameters such as the solvent, reaction temperature, operating pressure, catalyst loading, glycerol concentration and liquid flow rate on glycerol hydrogenolysis together with the catalyst stability were studied in detail, showing that the Ce-promoted Cu–Co–Al catalyst had high efficiency and stability for glycerol hydrogenolysis.
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![Tungstate(3-),tetracosa-m-oxododecaoxo[m12-[phosphato(3-)-kO:kO:kO:kO':kO':kO':kO'':kO'':kO'':kO''':kO''':kO''']]dodeca-,hydrogen (1:3)](http://img.cochemist.com/ccimg/1400/1343-93-7_b.png)
![(2S)-2-[[4-[[(6S)-2-amino-4-oxo-4a,5,6,7-tetrahydro-1H-pteridin-6-yl]methylamino]benzoyl]amino]pentanedioic acid](http://img.cochemist.com/ccimg/72000/71963-69-4.png)
![(2S)-2-[[4-[[(6S)-2-amino-4-oxo-4a,5,6,7-tetrahydro-1H-pteridin-6-yl]methylamino]benzoyl]amino]pentanedioic acid](http://img.cochemist.com/ccimg/72000/71963-69-4_b.png)
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