Strong Basicity Research Articles

A novel fluorescent probe with one-excitation and dual-emission for selective and simultaneous detection of Glutathione and Arginine in NIR and blue regions

A hydroxyphenylbenzothiazole (HBT)-based fluorescent probe (HBT-Py) was synthesized to selectively and simultaneously detect GSH and Arg in NIR (684 nm) and blue (469 nm) regions excited by 400 nm at the absolutely same measured conditions, respectively. After studied the detected mechanism through TLC, HRMS and optical data, we proposed that the detection for GSH could result from the Michael addition and esterlysis reactions between GSH and the probe, followed by ESIPT process to get the fluorescent signal at 684 nm. While the mechanism for detection Arg could be from esterlysis and ESIPT-block due to the strong basicity and formation of hydrogen bond from guanidine group in Arg.

Ca–Mg–Al ternary mixed oxides derived from layered double hydroxide for selective etherification of glycerol to short-chain polyglycerols

In this study, a magnesium (Mg) and aluminum (Al) layered double hydroxide (LDH) was used as a precursor in the preparation of calcium (Ca), Mg and Al ternary mixed oxides for selective conversion of glycerol into diglycerols via solvent-free glycerol etherification. The LDH-derived MgAl mixed oxide was saturated with an aqueous solution of Ca citrate complexes, followed by calcination at 700 °C, to obtain the Ca-MgAl mixed metal oxide (MMO) catalysts. The effects of the citric acid addition and Ca loading levels on the physicochemical and catalytic properties of the resulting Ca-MgAl MMO were investigated. The Ca-MgAl MMO series were characterized by a high Ca dispersion, high total basicity (236–482 μmol g−1), an enhanced amount of strong basic sites and a new mesoporosity. The highest diglycerols selectivity of 78.3 mol% was achieved at a glycerol conversion of 40.4 mol% when the reaction was performed over the Ca-MgAl MMO catalyst synthesized with a 7.5 wt% Ca loading level, at a 3 wt% catalyst loading, 220 °C for 24 h. The formation of ternary mixed oxides improved the structural stability of the pristine MgAl mixed oxide. The catalytic performance of Ca-MgAl MMO was compared with that of commercial MgAl mixed oxides and homogeneous base (Na2CO3). The presence of strong basicity in the MMO catalysts was a key part in the selective synthesis of diglycerols.

Insight into the effect of promoters (M = Cu, Ag, Zn, Zr) on aldol condensation reaction based on MgO surface in the process of ethanol to 1, 3-butadiene: A comparative DFT study

Based on density functional theory, the performance of aldol condensation of acetaldehyde to 3-hydroxybutanal on MgO surfaces doped with Cu/Ag/Zn/Zr was compared and analyzed, respectively. And the two kinds of coordination structures: terrace surface (Mg5C-O5C-T) and the kinks surface (Mg3C-O3C-K), were selected as the basis of MgO surface. Among these kinds of promoters, Zn and Ag have a little influence on the surface properties of MgO. While Cu and Zr could modify the acidity-basicity properties of MgO surfaces. Cu as the promoter could reduce the energy barrier of acetaldehyde enolization step on weak basicity site (Mg5C-O5C-T), and that of the proton back-transfer step on strong basic site (Mg3C-O3C-K) simultaneously. Moreover, Zr could promote both the formation of CC bond and proton back-transfer step on the strong basicity sites. It is speculated that strong basicity sites on MgO surface could be eliminated by the addition of Zr to avoid the excessive condensation of acetaldehyde, which could result in catalyst deactivation. In conclusion, Cu has a promoting effect on aldol condensation reaction on both two coordination structures of MgLC-OL'C ion pairs. Zr is beneficial to the performance of the strong basic catalyst.

Fabrication of superhydrophobic electrospun polyimide nanofibers modified with polydopamine and polytetrafluoroethylene nanoparticles for oil–water separation

ABSTRACTThe oil–water separation technologies of removing oil pollutants from water in an efficient and economical way is a challenge. The current methods used for oil–water separation suffer many shortcomings, including a low separation efficiency, complex separation equipment, high operation costs, and secondary pollution. In this study, we fabricated a highly flexible, high‐intensity, quite stable superhydrophobic and superoleophilic polyimide (PI) nanofibrous membranes, which are much more efficient and cost efficient for oil–water separation by modifying the membranes with a polydopamine (PDA) solution and polytetrafluoroethylene (PTFE) dispersion. The fabricated membrane (PDA–PTFE–PI) possesses both the high tensile stress of PI and the superhydrophobic and superlipophilic properties of the PDA–PTFE coating. The modified membrane could separate various oil–water mixtures efficiently at a high flux (6000 L·m−2·h−1) and an extremely high efficiency (>99%). Furthermore, even when the membrane was under an extremely hostile environment (with an ultrahigh temperature, strong acidity, or strong basicity), it still remained quickly stable with a good separation efficiency and recyclability after 10 cycles. We anticipate that our study will provide a new technology for the highly efficient mass production of oil–water mixture management. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47638.

Facile preparation of pore- and morphology-controllable ETS-10 zeolite with enhanced biomass hydrogenation activity

A detailed investigation was carried out to develop novel pore- and morphology-controllable ETS-10 zeolite. The XRD, N2 adsorption/desorption, SEM, TEM and 29Si NMR MAS results proved that a series of hierarchical ETS-10 zeolites was successfully synthesized and more importantly, their morphologies and pore sizes can be freely confined in the desired range under the mesoporogen, morphology- and structure-directing actions of different additives. What's more, the close relationship between various additives and raw materials especially titanium source was discussed, which played an active part in morphology change and hierarchical pores formation. This can be ascribed to the special reducibility of inorganic Ti source, system liquidity and pH, and the enhanced inorganic species dissolution. Finally, the synthesized hierarchical ETS-10 materials were used as heterogeneous catalysts for different biomass-derivatives hydrogenation. Remarkably catalytic performance can be attributed to the unique TiO6 octahedra carrying two negative charges that strengthens the interaction with active metal species, and thus improves their dispersion. Moreover, the inherent strong Lewis basicity and moderate Lewis acidity favor the oriented conversion of reactants. The controllably hierarchical structure and morphology benefit exposure of more highly dispersed active sites and prolong the catalyst life circle. Especially, an analogous molecular-recognition pattern was found by using sodium lignosulphonate, which is identified as the leading role in noticeably enhancing the catalytic activity and selectivity of the correspondingly ETS-10-based catalyst.

Effect of support materials and Ni loading on catalytic performance for carbon dioxide reforming of coke oven gas

To investigate the effect of support materials on catalytic performance in carbon dioxide reforming of coke oven gas, Ni-based catalysts supported on various metal oxides with various properties are prepared and evaluated. The support material affects the important properties related to the catalytic performance such as surface area, Ni dispersion, basicity, oxygen storage capacity, and interaction between Ni and support. Among the various catalysts on different metal oxides, Ni/MgOAl2O3 catalyst exhibits the highest CH4 conversion due to its high Ni dispersion, large surface area, and strong basicity. Hence, the Ni loading in the Ni/MgOAl2O3 catalyst is optimized. Ni loading performs the important roles to determine the Ni dispersion, the amount of Ni active sites, and basicity. 15 wt% Ni/MgOAl2O3 catalyst shows the highest catalytic activity even at a high gas hourly space velocity (GHSV) of 1,500,000 h−1, owing to the large amount of Ni active sites which related to Ni loading, Ni dispersion, and reduction degree. To confirm the stability of the 15 wt% Ni/MgOAl2O3 catalyst, catalytic reaction has been carried out for 50 h and noticeable catalytic deactivation is not observed for 50 h.

Palladium-catalyzed relay hydroaminocarbonylation of alkenes with hydroxylamine hydrochloride as an ammonia equivalent

Amides are prevalent in pharmaceuticals, agrochemicals, and materials. Hydroaminocarbonylation of alkenes has emerged as one of the most direct and rapid approaches to amides. Nowadays, these reactions remain largely confined to using alkylamines as nitrogen sources, leading to sluggish reactions due to their strong binding ability and basicity. Here we show the application of abundantly available hydroxylamine hydrochloride (NH2OH·HCl) as a surrogate of ammonia for the relay hydroaminocarbonylation of simple alkenes in the presence of a convenient palladium catalyst system. The in situ formation of alkylamines from hydroxylamine hydrochloride by hydroaminocarbonylation reaction and Lossen rearrangement allows us to establish an efficient relay hydroaminocarbonylation. Notably, this transformation allows the catalytic formation of two C–N bonds with hydroxylamine hydrochloride as an amine source by incorporation of two molecules of alkene and avoids the use of alkylamines.

Visual and Precise Detection of pH Values under Extreme Acidic and Strong Basic Environments by Cellulose-Based Superior Sensor.

Precise determination of pH values with an instrument-free mode is challenging and practical in industry processes, life science, and environmental monitoring. Here, taking advantage of the intramolecular charge transfer process, we construct a cellulose-based superior pH sensor, Phen-MDI-CA, which contains a highly sensitive, pH-responsive, and extended conjugation structure by combining phenanthroline moiety as a chromophore with urea group as a bridge. The resultant Phen-MDI-CA can precisely and visually determine pH values under extreme acidic and strong basic environments, depending on the different colors. In visible light mode, Phen-MDI-CA can readily discriminate the pH values of 14.0, 13.0, 12.0, and 11.0 and distinguish pH 2.0 from 1.0 by the naked eye. In fluorescent mode, Phen-MDI-CA can recognize more accurate pH values of pH 11.6-13.2 at a 0.2-0.4 pH interval by the high-contrasting color change. After addition of pH-irresponsive dyes as the reference, the corresponding ratiometric systems exhibit different colors at a 0.2-0.4 pH interval during the pH values of 11.0-14.0 and 1.0-2.0. Benefiting from the excellent formability, the Phen-MDI-CA was readily fabricated into pH test strips by coating method. To our knowledge, this is the first study to monitor extreme acidity and strong basicity in such precise pH values with an instrument-free mode.

Dry Reforming of Propane over γ-Al2O3 and Nickel Foam Supported Novel SrNiO3 Perovskite Catalyst

The SrNiO3 perovskite catalyst was synthesized by the citrate sol-gel method and supported on γ-Al2O3 and Nickel foam, which was used to produce syngas (CO and H2) via dry reforming of propane (DRP). Several techniques characterized the physicochemical properties of the fresh and spent perovskite catalyst. The X-ray diffractograms (XRD) characterization confirmed the formation of the perovskite compound. Before the catalytic activity test, SrNiO3 perovskite catalyst was reduced in the H2 atmosphere. Results indicated that the H2 reduction slightly increased the activity of the SrNiO3 perovskite catalyst. The catalytic activity was examined for the CO2/C3H8 ratio of 3 and reaction temperatures in the range of 550 °C–700 °C. The results from the catalytic study achieved 88% conversion of C3H8 and 66% conversion of CO2 with SrNiO3/NiF at 700 °C. Also, syngas with a maximum concentration of 21 vol.% of CO and 29 vol.% of H2 was produced from the DRP. The strong basicity of SrNiO3 perovskite enhanced the CO selectivity, resulting in minimal carbon formation. Post reaction catalyst characterization showed the presence of carbon deposition which could have originated from propane decomposition.

A highly active and selective mesostructured Cu/AlCeO catalyst for CO2 hydrogenation to methanol

Mesostructured catalysts with optimized microstructure and surface properties endowed them attractive catalytic performance. Herein, the mesostructured AlCeO supports with different weight ratio of Al2O3 and CeO2 have been prepared on the basis of a self-assembly sol-gel process, then 15 wt.% Cu was loaded onto the mesostructured AlCeO supports by incipient wetness impregnation method. The mesostructured AlCeO supports with varied ratio of Al2O3 to CeO2 resulted in the very different Cu particle size, and for the optimized catalyst Cu/AlCeO-7 (the amount of Al2O3 in AlCeO support was 70 wt.%), the Cu crystal size was around 7 nm based on the characterization of XRD and TEM. The Cu/AlCeO-7 catalyst had strong metal-support interactions (SMSI) and more Cu-ceria interface, which was confirmed by the XPS. Furthermore, the Cu/AlCeO-7 catalyst showed the highest exposed Cu surface area (SCu) (25.5 m2/gcat) from the analysis results of H2-TPR and dissociative chemisorption of nitrous oxide. The CO2-TPD results demonstrated the Cu/AlCeO-7 had strong surface basicity. Hence, Cu/AlCeO-7 catalyst showed the highest space time yield of methanol (STYMeOH). The CO2 conversion (Cu/AlCeO-7, V(H2)/V(CO2) = 3/1, GHSV = 6000 mL h−1 g−1 and P = 4 MPa) was up to 22.5% at 553 K, the methanol selectivity can reach 94% at 473 K, and the STYMeOH was up to 7.2 mmol gcat.-1 h-1 at 493 K. The as-prepared mesostructured Cu/AlCeO-7 exhibited a promising catalyst candidate for CO2 hydrogenation to methanol.

Syngas-derived olefins over iron-based catalysts: Effects of basic properties of MgO nanocrystals

A series of Fe/MgO catalysts with well-defined exposed crystal planes were synthesized by impregnation, deposition-precipitation and ultrasonic impregnation methods. The catalysts were characterized by X-ray powder diffraction, high-resolution transmission electron microscopy, CO2 temperature-programmed desorption, H2 temperature-programmed reduction, X-ray spectroscopy and N2 adsorption-desorption isotherms. The characterization results indicate that the basicity of MgO supports strongly affect the catalytic performance of iron-based catalysts for Fischer-Tropsch synthesis. It is found that the strong basicity sites of MgO supports remain during the ultrasonic impregnation process. The intrinsic basicity of Fe/MgO catalysts enhances dissociative CO adsorption and promotes the olefin selectivity. In addition, the catalyst of iron particles on the (111) crystal planes of MgO nanosheets presents higher TOF value and olefins selectivity than that of the catalyst using the (100) crystal planes of MgO nanocubes as a support. The effect of basic properties of MgO nanocrystals facilitates CO chemisorption, suppressing H2 adsorption and olefin desorption on the corresponding Fe/MgO catalysts.

Highly stable and anti-coking Ni/MoCeZr/MgAl2O4-MgO complex support catalysts for CO2 reforming of CH4: Effect of the calcination temperature

Catalyst deactivation by coking and sintering over Ni-based catalysts is still an open question for carbon dioxide reforming of methane (CDRM). Here, Ni/MoCeZr/MgAl2O4-MgO complex support catalysts were successfully synthesized by calcination of the Ce, Zr and Mo promoted NiMgAl-hydrotalcite-like precursors using a simple one-step co-precipitation method. Particular attention was paid to the anti-coking properties and catalytic behaviors of these complex support catalysts prepared at different calcination temperatures (700, 800 and 900 °C). Under harsh conditions (at 900 °C under GHSV of 60,000 mL·h−1·gcat−1 and without using inert gases as diluents), the catalyst calcined at 800 °C yielded a high conversion of CH4 and CO2 above 95% and long-term stability for 658 h without any remarkable coke deposition (only 0.015 mgC·h−1·gcat−1), outperforming the catalysts obtained at other calcination temperatures. Coking analysis showed that all the catalysts generated negligible coke deposition, indicating that solving the coke deposition problem puzzled researchers for many years is possible. Further analysis revealed that the generation of small Ni nanoparticles (<9 nm), strong basicity and intimated metal-support interactions coupled with the high reaction temperature might be the reasons for the stable coke-free process. This work may serve as an important reference for other kinds of catalysts suffering deactivation due to coking and/or sintering.

Effect of alkaline‐earth metals on synthesis of isobutyraldehyde from methanol and ethanol over Cu‐MeOx/Ti‐SBA‐15 catalysts (Me = Mg, Ca, Sr, Ba)

AbstractCu‐MeO/Ti‐SBA‐15 catalysts (Me = Mg, Ca, Sr, and Ba) were used for isobutyraldehyde (IBA) synthesis from methanol and ethanol and characterized by various techniques including XRD, N2 sorption, CO2‐TPD, XPS, etc. Doping different alkaline‐earth meals (Me = Mg, Ca, Sr, and Ba) to Cu/Ti‐SBA‐15 can significantly affect catalytic performance in IBA synthesis. Based on characterizations, different alkaline‐earth metal doping significantly affects the amount of basic sites and the basic strength of the catalyst surface and their interaction with active Cu and other components. Therefore, the higher activity of the catalyst is closely related to larger amounts of basic sites, stronger basicity, and stronger interaction between Cu and MeO.

Catalytic cracking of rubber seed oil using basic mesoporous molecular sieves K2O/MeO-SBA-15 (Me = Ca, Mg or Ba) as heterogeneous catalysts for the production of liquid hydrocarbon fuels

Liquid hydrocarbon fuels obtained from the catalytic cracking animal fats and plant oils have become one kinds of the attractive fuels because of their possible environment benefits and the current concern over the depletion of fossil fuel sources. In this work, using the combined methods of one-pot synthesis and wetness-impregnation, some basic mesoporous molecular sieves K2O/MeO-SBA-15 (Me = Ca, Mg or Ba) were prepared, characterized and used in the catalytic cracking of rubber seed oil (RSO). The results indicated that the catalysts K2O/MeO-SBA-15 had better catalytic performances than MeO-SBA-15, assigning to their stronger basicity. The catalyst K2O/MgO-SBA-15 obtained with 15 wt% KNO3 impregnation concentration showed the excellent catalytic performance with about 93.2% conversion and 78.3% yield of liquid hydrocarbon biofuel. The obtained liquid biofuel had similar chemical composition to diesel-based fuels and showed good cold flow property, high calorific and low acid value. Importantly, the catalyst K2O/MgO-SBA-15 was of excellent reusability, and it was reused with negligible loss in its catalytic performance for five times, attributing to the MgO layer between silicon skeleton and potassium species which prevents the reaction between silicon in the framework and potassium species.

Knoevenagel Condensation of Aldehydes and Ketones with Alkyl Nitriles Catalyzed by Strongly Basic Anion Exchange Resins under Continuous‐Flow Conditions

AbstractThe use of strongly basic anion exchange resins as catalysts for Knoevenagel condensations under continuous‐flow conditions was investigated. It was found that Amberlite FPA60 was an efficient solid base catalyst for the flow synthesis of 1,2‐disubstituted alkenyl nitriles from arylmethyl nitriles and aldehydes. On the other hand, the Knoevenagel reaction involving acetonitrile required elevated reaction temperatures, which necessitated a change to a thermally robust ammonium hydroxide polymer catalyst. The potential applications of these strongly basic anion exchange resins for multi‐step continuous‐flow synthesis were also demonstrated.

Tuning the basicity of Cu-based mixed oxide catalysts towards the efficient conversion of glycerol to glycerol carbonate

A series of efficient and robust Cu based mixed oxides were synthesized by a simple co-precipitation method and utilized for the production of glycerol carbonate (GC) via transesterification of glycerol with dimethyl carbonate (DMC). The synthesized materials were characterized using XRD, UV–vis spectroscopy, SEM, TEM, N2 sorption, CO2-TPD, and XPS. The addition of Cu on Mg/Al mixed oxides exhibits significant changes in its physicochemical properties and catalytic activity. The obtained mixed oxides showed remarkably high transesterification activity towards the efficient conversion of glycerol to GC under economical reaction conditions without using any solvent. Among all the catalysts employed, highest catalytic activity was observed over MAC-0.6 catalyst with glycerol conversion of 96.4% and GC yield of 91.2%. The improved catalytic performance was observed mainly due to the optimized catalyst molar ratio and strong surface basicity. The strong surface basic sites were greatly attributed to the incorporation of Cu2+ cations in the MgAl (O) periclase that efficiently catalyzed the transesterification of glycerol with DMC. Furthermore, the reported catalyst was robust and could be recycled for more than five times without any significant loss in its catalytic activity.

Supported ionic liquid membranes with high carrier efficiency via strong hydrogen-bond basicity for the sustainable and effective olefin/paraffin separation

Supported ionic liquid membranes (SILMs) constitute a radical advance in olefin/paraffin separation membranes. Unfortunately, the applications of SILMs are vastly hindered by low carrier efficiency. Herein, SILMs with high carrier efficiency via strong hydrogen-bond basicity were designed to carry out efficient ethylene/ethane separation. The strong hydrogen-bond basicity of ILs not only endowed the membranes with high carrier concentration, but also effectively favored for the good disassociation of carrier to form solvated free ions through coordinative interactions between IL and carrier, which greatly increased the number of carrier and enhanced the carrier efficiency. Benefiting from the high carrier efficiency, both ethylene permeability and ethylene/ethane selectivity were significantly elevated, which could reach up to 100 Barrers and 40, respectively, surpassing most of results reported in the open literature. Meanwhile, the ethylene and ethane solubility data in the carrier/ILs were measured in a pressure range from 0 to 3.5 bar at 298.15 K, a first-order equilibrium model based on the formation carrier-ethylene complex species has been developed to describe the physical and chemical dissolving behaviors of ethylene and the equilibrium constants were obtained accordingly. Moreover, the membrane separation process was optimized, confirming that ethylene permeability and ethylene/ethane selectivity increased with the increase of carrier concentration due to the combined effects of gas solubility and diffusion. It was notable that the selectivity of as-prepared SILMs was more effective at lower transmembrane pressures and operating temperatures, which contributed to designing the energy-efficient and sustainable membrane processes. This study opens a new route for the utilization of the IL properties to manipulate the carrier efficiency for developing high performance SILMs.

Solvent-Assisted Stepwise Redox Approach To Generate Zeolite NaA-Supported K2O as Strong Base Catalyst for Michael Addition of Ethyl Acrylate with Ethanol.

Solid base catalysts featuring green, robustness, and high activity play an important role in the current fine-chemical and petrochemical industry. Normally, the generation of supported K2O by thermal decomposition of KNO3 requires high temperature, and this process can sometimes destroy the structure of supporting materials. We herein report a solvent-assisted stepwise redox (SASR) approach to generate zeolite NaA-supported K2O, which we call K2O/NaA, that function as the solid base catalyst for Michael addition reaction between ethanol and ethyl acrylate. The solvent-assisted redox decomposition process of KNO3 at elevated temperature was investigated by thermogravimetry–mass spectrometry. It reveals that after reducing a minor amount of KNO3 at 400 °C, the organic solvent decomposes to form carbon, which promotes the reduction of KNO3 to generate strong basicity on the zeolite NaA at 600 °C. The resulting material, K2O/NaA-S, exhibits improved catalytic activity in Michael addition reaction over other benchmark base catalysts that have been used in this reaction. This catalyst is durable for at least four catalytic cycles without apparent loss in activity. K2O/NaA-S exhibits larger reaction rate constant yet lower activation energy than K2O/NaA prepared by thermal decomposition method. The SASR approach described in this paper represents a new blueprint for the generation of the supported alkali oxide as the solid base catalyst.

Theoretical Study of Propylene Epoxidation over Cu2O(111) Surface: Activity of O2–, O–, and O2– Species

Propylene epoxidation catalyzed by cuprous oxide in the presence of oxygen species is important in both technology and scientific fields, and the active species—lattice oxygen (O2–), adsorbed atomic oxygen (O–), or adsorbed molecular oxygen (O2–)—plays a significant role in the catalytic reaction. In the present work, the mechanism of propylene epoxidation and dehydrogenation on a Cu2O(111) facet with different oxygen species has been studied through density functional theory (DFT) calculations with a Hubbard U correction in detail. The whole reaction processes of propylene oxidation includes two different routes: allylic hydrogen stripping (AHS) reactions and propylene epoxidation reactions. Acrolein can be generated by two H-stripping reactions in the AHS path, and propylene oxide (PO) is formed through the oxametallacycle propylene (OMP) intermediate. The calculated results show that the adsorbed atomic oxygen (O–) is the most active oxygen species for the selective oxidation of propylene because it has the strongest basicity among these three oxygen species, whereas the adsorbed molecular oxygen (O2–) has the highest selectivity for the PO formation among these three different oxygen species because of its relatively low basic properties and moderate oxidation compared to those of atomic oxygen (too active oxidation) or lattice oxygen (less oxidation due to the closed-shell nature of the oxide system). Moreover, a microkinetic simulation was used to confirm the above DFT calculation results. The aim of the present study is to give a guide in choosing the most efficient active oxygen species for PO formation, which should be the one with the moderate oxidant.

Transesterification of ethylene carbonate with methanol over Zn-La mixed oxide catalysts

The transesterification of ethylene carbonate (EC) with methanol to synthesis dimethyl carbonate (DMC) and ethylene glycol (EG) over ZnO, La2O3 and Zn-La mixed oxides were explored. The catalysts were prepared by co-precipitation method and characterized by BET, XRD, TG-DSC, CO2-TPD and Hammett titration. The influence of Zn/La atomic ratio, calcination temperature and reaction parameters (reaction temperature, reaction time, catalyst amount) on the catalytic activity were investigated. The results indicated that the binary Zn-La mixed oxide with Zn/La atomic ratio of 2:1 calcined at 500°C showed the highest catalytic performance for the title reaction due to its strongest basicity, and the amount of strong basic sites of the catalyst should be responsible for the high transesterification activity.