Co-doped NH2-MIL-125(Ti) catalysts [Co/NH2-MIL-125(Ti)] are developed for the photocatalytic reduction of CO2 upon visible-light irradiation. Compared with NH2-MIL-125(Ti), Co/NH2-MIL-125(Ti) exhibits a significantly enhanced activity in CO2 reduction, due to the fact that the doping of Co nanoparticles onto NH2-MIL-125(Ti) can promote the visible-light harvesting and electron transfer. In addition, when benzylic alcohols as electron donors, instead of triethanolamine (TEOA) which is often used as a sacrificial agent, are added into the reaction system, Co/NH2-MIL-125(Ti) can simultaneously catalyze CO2 reduction to formic acid (HCOOH) and the selective oxidation of the benzylic alcohols to the corresponding aldehydes, making the proposed process more economical and environment-friendly.

•Synthesis of amino-functionalized mesoporous silicas (AFMS) with high amino loading.•Single- and multi-component adsorption of Cu2+, Pb2+, Cd2+, and Zn2+ on the AFMS.•The high adsorption capacities and fast uptake rates on the AFMS.•Pb2+ and Cu2+ can be more selectively removed by the AFMS.Amino-functionalized mesoporous silicas (AFMS) were synthesized by a neutralization route using the anionic surfactant dodecanoic acid (DAA) as structure-directing agent (SDA), aminopropyltrimethoxysilane (APTMS) as co-structure-directing agent (CSDA), and tetraethoxysilane (TEOS) as silicon source. The synthesis parameters, which affect the structural properties and the amino loadings of the resultant AFMS, were optimized. Various techniques, such as FT-IR, XRD, N2 adsorption-desorption, and TEM, were used to characterize the synthesized AFMS. The selective removal of Cu2+, Pb2+, Cd2+, and Zn2+ from aqueous solutions in single-, binary-, ternary-, and quaternary-component systems by the synthesized AFMS was thoroughly investigated. The measured single-component adsorption isotherms of Cu2+, Pb2+, Cd2+, and Zn2+ on the AFMS optimally synthesized can be well described by the Sips model, in which the extracted adsorption capacities are 2.34, 2.86, 1.71, and 1.36 mmol/g (0.149, 0.593, 0.192, and 0.089 g/g) for Cu2+, Pb2+, Cd2+, and Zn2+, respectively, higher than those on other adsorbents reported in the literature. Furthermore, Pb2+ and Cu2+ can be more selectively removed by the synthesized adsorbent, compared to Cd2+ and Zn2+, confirmed by the results on the multi-component adsorption.

The selective separation of C2H6/C2H4 mixtures can be achieved by the zeolitic imidazolate framework ZIF-7, which is a well-known flexible microporous material due to its gate-opening effect in response to external stimuli such as pressure and temperature. Transient breakthrough experiments with C2H6/C2H4 mixtures were carried out at varying pressure and temperature conditions to confirm the potential application of ZIF-7 to selectively adsorb the saturated alkane and reject the unsaturated alkene in the gas phase during the adsorption cycle. Transient breakthrough simulations, including the influence of intra-crystalline diffusion, were compared with the experimental breakthroughs. The assumption of negligible diffusional limitations is able to capture the essential characteristics of the experimental breakthroughs. With the breakthroughs from both experiments and simulations, the adsorbed amounts of C2H6 and C2H4 in ZIF-7 were calculated to estimate the separation selectivity, which is in reasonable agreement with ideal adsorbed solution theory calculations. The derived isosteric heats of adsorption for both adsorbates are compared and used to explain the adsorption selectivity for C2H6 over C2H4 in ZIF-7. The good agreement between experiments and simulations verifies that the simulation methodology employed in the current study is a valuable and efficient tool for modeling the separation performance of C2H6/C2H4 mixtures in ZIF-7.ZIF-7 is a potential adsorbent for the selective separation of C2H6/C2H4 mixtures, where the concentrated C2H4 can be recovered in the adsorption cycle.

The Keggin-structured heteropolyacid H4PMo11VO40 and its triethylamine-modified derivative [(C2H5)3NH]4PMo11VO40 were prepared and characterized by FT-IR and UV–visible spectrometry, and elemental analysis. Direct hydroxylation of benzene to phenol by H2O2 over these two catalysts was then compared. The effect of the triethylamine in [(C2H5)3NH]4PMo11VO40 on the catalytic hydroxylation of benzene was investigated in detail. The results showed that although the triethylamine-modified catalyst is not significantly more active than the parent heteropolyacid catalyst, its reaction-controlled phase-transfer characteristics enable easy separation of the catalyst from the reaction medium, and its reuse, suggesting its potential for application to the hydroxylation of benzene to phenol with H2O2.

N2O is a greenhouse gas with tremendous global warming potential, and more importantly it also causes ozone depletion; thus, the separation of N2O from industrial processes has gained significant attention. We have demonstrated that N2O can be selectively separated from CO2 using the zeolite imidazolate framework ZIF-7. The adsorption/desorption isotherms of both N2O and CO2 in ZIF-7 indicate the gate-opening mechanism of this material, and surprisingly, the threshold pressure for the gate opening with N2O is lower than that with CO2. Theoretical calculations indicate that both gas–host and gas–gas interaction energies for N2O are more favorable than those for CO2, giving rise to the difference in the threshold pressure between N2O and CO2 in ZIF-7. Breakthrough experiments for N2O/CO2 mixtures confirm that ZIF-7 is capable of separating N2O and CO2 mixtures under the optimized conditions, in reasonable agreement with simulation results, making it a promising material for industrial applications.

The sulfoxy or sulfonic acid-functionalized MIL-101 catalyst was prepared by either post-functionalization or pre-modification of the organic linkers with the functionalized ligands, respectively, the latter is the so-called one-pot synthesis method. These catalysts were systemically characterized by XRD, N2 adsorption, acid–base titration, and FT-IR techniques and applied in the liquid-phase esterification of monocarboxylic acids with monohydric alcohols. The results show that the sulfonic acid-functionalized MIL-101 (S-MIL-101) prepared by the one-pot synthesis method possesses a higher catalytic activity in the esterification than its counterpart the sulfoxy acid-functionalized MIL-101 (S/MIL-101) prepared by the post-functionalized method, due to the fact that S-MIL101 has a higher acid loading and a high utilization efficiency of the functionalized acid sites. Moreover, S-MIL-101 is stable to leaching, behaves as a true heterogeneous catalyst, can be easily recovered by filtration, and can be reused five times in succession without any loss of its catalytic activity.

FeZSM-5 zeolites with crystal sizes ranging from 70 nm to 20 μm were synthesized by adjusting the alkalinity of the synthesis system and optimizing the crystallization conditions. After steam-activated treatment, these zeolites were used as catalysts in the direct decomposition of N2O, showing that the larger the zeolite crystal size, the higher the reaction temperature required for the complete decomposition of N2O. Moreover, N2O decomposition over the FeZSM-5 catalysts with crystal sizes larger than 5 μm at high temperatures shows that the conversion of N2O decreases with increasing the zeolite crystal size, implying that the internal mass transfer limitations are available. However, under the applied conditions, the diffusion limitations are absent and the observed reaction rates are controlled by the intrinsic kinetics of N2O decomposition over the FeZSM-5 catalysts with crystal sizes smaller than 2 μm.Graphical abstractThe conversion of N2O over FeZSM-5 catalysts at 525 °C decreases with increasing the zeolite crystal size.Highlights► Tailored synthesis of FeZSM-5 crystals with different sizes. ► Investigation on internal mass transfer limitations for N2O decomposition. ► The crystal size of FeZSM-5 significantly affects its observed activity. ► Diffusion limitations are available over the zeolite crystals larger than 5 μm.

A series of polyoxometalate (POM)-based amphiphilic catalysts were prepared via functionalization of the V-containing Keggin POM H4PMo11VO40 by cationic surfactants with different carbon-chain lengths. These prepared catalysts were systematically characterized by Fourier transform infrared (FT-IR), 1H nuclear magnetic resonance (NMR), thermogravimetric (TG), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption, and X-ray diffraction (XRD) techniques as well as by the elemental analysis. Their catalytic activities were evaluated in the selective oxidation of benzyl alcohol to benzaldehyde by H2O2 under organic solvent-free conditions. Among the catalysts investigated, the amphiphilic (ODA)4PMo11VO40 (ODA: octadecylmethylammonium) shows the highest catalytic efficiency for the selective oxidation. The high activity and selectivity of the prepared (ODA)4PMo11VO40 are probably related to its amphiphilic property. A maximum conversion of benzyl alcohol is 60.6% with a selectivity of 99% for benzaldehyde under the optimized reaction conditions over (ODA)4PMo11VO40, which offers excellent reusability, confirmed by the recycling of the used catalyst.

A comparison study has been conducted on the strategies for synthesizing nanocrystalline Li2ZrO3 and Kdoped Li2ZrO3 absorbents for CO2 capture at high temperatures, including solid-state and liquid-phase methods, citrate route, and starch-assisted sol-gel method combined with freeze-drying technique. The absorption properties, including uptake rate and absorption capacity, of synthesized absorbents were investigated by thermogravimetric analysis (TGA) at different CO2 partial pressures. The nanosized Li2ZrO3 crystals synthesized by the citrate route exhibit a faster uptake and a higher, nearly stoichiometric absorption capacity than those synthesized by the solid-state and liquid-phase methods. The doping of K into Li2ZrO3 can significantly improve the uptake rate of CO2, especially at low CO2 partial pressures. For the synthesis of K-doped Li2ZrO3, the citrate route has poor reproducibility and scalability, whereas the starch-assisted sol-gel method combined with freeze-drying technique is reproducible and easily scaled up, and the thus synthesized absorbents possess excellent CO2 capture properties.

A highly regio-, chemo-, diastereo- and enantioselective organocatalytic [4 + 1] annulation of 2-halo-1,3-dicarbonyl compounds with Morita–Baylis–Hillman adducts catalyzed by commercially available, low cost quinidine for the preparation of synthetically unique and medicinally multi-functionalized isoxazoline N-oxides with three stereogenic centers including adjacent quaternary and tertiary stereocenters has been developed. Notably, the unexpected product ethyl 2-((tert-butyldimethylsilyl)oxy)-2-(5,5-diacetyl-3-((methylsulfonyl)oxy)-4-phenylisoxazolidin-3-yl)acetate (8) bearing a quaternary stereocenter and two tertiary stereocenters was obtained from the undocumented 5,5-diacetyl-3-(2-ethoxy-1-hydroxy-2-oxoethyl)-4-phenyl-4,5-dihydroisoxazole 2-oxide (4ba).

A series of functionalized 2,3-dihydro-1,4-benzoxazines were obtained in moderate to excellent yields via domino [5 + 1] annulations of 2-halo-1,3-dicarbonyl compounds 2 with imines 1 under mild conditions and the application of this method in the synthesis of bioactive analogues, such as functionalized tetracyclic-1,4-benzoxazines which contain two new heterocyclic rings and one quaternary carbon center has also been developed.

Amino-functionalized silica spheres with centrosymmetric radial mesopores and high amino loading were synthesized using the anionic surfactant N-lauroylsarcosine sodium (Sar-Na) as template and 3-aminopropyltrimethoxysilane (APTMS) as co-structure directing agent (CSDA) by an orthogonal experiment optimization. The synthesized amino-functionalized mesoporous silica (AFMS) was used as adsorbent to the selective adsorption of CO2. The effects of water vapor in the adsorptive stream on the adsorption properties of CO2 were investigated in detail. The results show that the synthesized adsorbent possesses a high adsorption selectivity for CO2 over CH4 and N2 due to the specific interactions between CO2 and amino groups. The presence of water vapor in the adsorptive stream can dramatically enhance the adsorbed amount of CO2 because of the partial formation of bicarbonate in the presence of moisture. Furthermore, the adsorbent shows a good stability, confirmed by adsorption-regeneration cycles. Based on these excellent properties, the application of the developed AFMS adsorbent in the selective adsorption of CO2 is anticipated.

Li2ZrO3 nanocrystals with improved CO2 capture properties were synthesized by a citrate sol–gel method. The morphology and structure of the synthesized Li2ZrO3 samples were characterized in detail by SEM, TEM, and XRD techniques. The CO2 capture–regeneration properties of these nanocrystals were investigated by thermogravimetric analysis (TGA) over a wide range of temperatures and of CO2 partial pressures. The nanosized Li2ZrO3 crystallites with a tetragonal phase exhibit a better CO2 capture performance than reported sorbents, exhibiting a faster uptake and a higher, nearly stoichiometric adsorption capacity (∼26 wt.%). Furthermore, the adsorbent shows a good stability, confirmed by capture–regeneration cycles. Based on these excellent properties, application in sorption-enhanced reaction process (SERP) is anticipated.

Fe-ZSM-5 zeolites with uniform crystal size and shape were synthesized by a hydrothermal method, and these parent zeolites were desilicated by an alkaline-treatment method to obtain mesoporous Fe-ZSM-5 (meso-Fe-ZSM-5) zeolites. Both Fe-ZSM-5 and meso-Fe-ZSM-5 zeolites were characterized by XRD, N2 adsorption–desorption, ICP-AES, SEM, TEM, UV-vis, and TGA techniques and as catalysts they were used in the direct oxidation of benzene to phenol (BTOP) by N2O as oxidant. The meso-Fe-ZSM-5 catalysts show a much higher catalytic activity and stability, compared to the parent Fe-ZSM-5 catalysts. A comparison study on the uptakes of benzene in the parent and alkali-treated zeolites indicates that the internal mass-transfer limitations of the meso-Fe-ZSM-5 zeolites are significantly improved due to the introduction of intracrystalline mesoporosity, resulting in a better catalytic activity and stability in the BTOP reaction. Desilication in the alkaline medium of Fe-ZSM-5 crystals enables a more efficient utilization of the zeolite in the BTOP reaction that is strongly affected by diffusional limitations.

In a neutral buffer system (Tris–HCl), the sheet-like mesoporous silica SBA-15 with regular hexagonal array was synthesized in the presence of the triblock copolymer P123 and the organic salt Na2EDTA. The small angle X-ray scattering, N2 adsorption–desorption, SEM, and TEM techniques were used to investigate the topology and morphology of the synthesized mesoporous silica, which shows a well-ordered hexagonal mesostructure and a sheet-like morphology. The mesopore channels in the synthesized material are perpendicular to the sheet plane. The strategy via the addition of the organic salt Na2EDTA provides an alternative to synthesize SBA-15 with a sheet-like morphology under mild conditions.

Amino-functionalized SBA-15 materials were synthesized by cocondensation of tetraethoxysilane (TEOS) with organosilane aminopropyltrimethoxysilane (APTMS) in a wide range of molar ratios of APTMS to TEOS in the presence of triblock copolymer P123 under acidic synthesis conditions. The effects of F– periodically added into the synthesis solution and of the APTMS concentration in the initial synthesis solution on the textural properties of the functionalized SBA-15 were investigated in detail. The addition of APTMS into the initial synthesis solution can adversely affect the SBA-15 mesostructure, whereas the ordered mesostructure of the amino-functionalized SBA-15 materials can be reserved by the introduction of F– into the synthesis solution. The results from the adsorption of CO2 on the synthesized materials show that the mesoporous SBA-15 functionalized with a high concentration of APTMS in the initial synthesis solution in the presence of F– could be a potential adsorbent for CO2 capture and separation.

The adsorption isotherms of CFC-115 (1-chloro-1,1,2,2,2-pentafluoroethane) and HFC-125 (1,1,1,2,2-pentafluoroethane) on Vruf activated carbon (Calgon Carbon Corp.; brand code, VRU-F) and silicalite-1 have been accurately measured at pressures up to 120 kPa and temperatures ranging from 273 to 348 K. The Tóth or dual-site Langmuir (DSL) model appropriately describes the equilibrium data for the adsorptives CFC-115 and HFC-125 on Vruf carbon or silicalite-1, respectively. Because HFC-125 molecule has a higher packing efficiency in the pores of Vruf carbon, its saturation capacity extracted by the Tóth model is higher than that for CFC-115. For CFC-115, a “kink” in the isotherm on silicalite-1 is observed at about 4 molecules (unit cell of silicalite-1)−1, and the measured isotherms of CFC-115 for the first time show a second-step adsorption at loadings over 4 molecules (unit cell)−1. This is ascribed to a large difference in the adsorption entropy between the molecular locations in the intersections and in the channels. The DSL model with fixed saturation capacities describes this behavior well. The mixture adsorption isotherms predicted by the ideal adsorbed solution theory show that both adsorbents could be industrially applicable in the separation of CFC-115 and HFC-125.

Amino-functionalized silica nanospheres with centrosymmetric radial mesopores were successfully prepared using the anionic surfactant N-lauroylsarcosine sodium (Sar-Na) as template and 3-aminopropyltrimethoxysilane (APMS) as co-structure directing agent. The template was efficiently removed by extraction either using a basic solution of monoethanol amine (MEA) in ethanol or an acetonitrile solution acidified with HCl. The synthesized mesoporous silica materials were characterized by the FT-IR, TG-DTA, XRD, N2 adsorption–desorption and TEM techniques. CO2 adsorption at 25 °C was evaluated by a volumetric method, and CO2 desorption was studied by the TPD technique. The results indicate that, compared to the sorbent treated with acidic-acetonitrile, the sorbent treated with the MEA–ethanol solution has a much higher adsorption capacity towards CO2, exhibits a higher degree of reversibility in the adsorption process, and has a much higher CO2/N2 selectivity.

The adsorption equilibria of nitrous oxide (N2O) on three commercial activated carbons were systematically investigated by means of a volumetric method at pressures up to 101 kPa and temperatures ranging from (195 to 323) K. The multiple-process adsorption equilibrium model appropriately describes the equilibrium data over the whole range of the applied conditions. The estimated total adsorption capacity of N2O is higher for activated carbon which possesses a higher pore volume determined by N2 adsorption at 77 K. The thermodynamic properties such as the adsorption equilibrium constant and enthalpy associated with adsorption were derived to characterize interactions between adsorbate and adsorbent.

Various catalysts, including the heteropolyacid (HPA) H4PMo11VO40, its cesium salts, and inorganic–organic dual modified HPA catalyst, were prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (13C NMR), N2 adsorption, acid–base titration, electron spin resonance (ESR) and X-ray diffraction (XRD) techniques as well as elemental analysis. These prepared catalysts were used in the hydroxylation of benzene to phenol by H2O2 as oxidant. The inorganic–organic dual modified HPA Cs2.5(MIMPS)1.5PMo11VO40, prepared by partially exchanging Cs+ with protons in H4PMo11VO40 and followed by the immobilization of 3-(1-methylimidazolium-3-yl)propane-1-sulfonate (MIMPS), led to a liquid–solid biphasic catalysis system in the hydroxylation, which showed the best catalytic performance in terms of reusability and catalytic activity. The high reusability of Cs2.5(MIMPS)1.5PMo11VO40 in the heterogeneous hydroxylation was probably due to its high resistance in leaching of bulk HPA into the reaction medium. The slightly enhanced catalytic activity for the catalyst was due to the acid sites available from MIMPS beneficial to the hydroxylation.The inorganic–organic dual modified heteropolyacid Cs2.5(MIMPS)1.5PMo11VO40, prepared by partially exchanging Cs+ with protons in H4PMo11VO40 and followed by the immobilization of 3-(1-methylimidazolium-3-yl)propane-1-sulfonate (MIMPS), led to a liquid–solid biphasic reaction system for hydroxylation of benzene with H2O2, which showed the best catalytic performance in terms of reusability and catalytic activity. The high reusability of Cs2.5(MIMPS)1.5PMo11VO40 in the heterogeneous hydroxylation was probably due to its high resistance of leaching of bulk heteropolyacid into the reaction medium. The slightly enhanced catalytic activity for the catalyst was due to the acid sites available from MIMPS beneficial to the hydroxylation.Download full-size image

Ethylenediamine moieties with different amounts were incorporated into the metal–organic framework MIL-101 to prepare the amino-functionalized MIL-101 materials, which were used as heterogeneous catalysts in the one-pot synthesis of nitroalkenes via the Henry reaction. Various reaction conditions were optimized. Under the optimized conditions, the selectivity towards nitroalkenes is extremely high in combination with nearly complete conversion of the reactant nitroalkanes. The amino-functionalized MIL-101 behaves as a true heterogeneous catalyst, can be easily recovered by filtration, and can be reused at least twice without significant loss of its catalytic performance.Download full-size imageHighlights► Amino-functionalized MIL-101 catalyst was prepared and applied in the Henry reaction. ► One-pot synthesis of nitroalkenes via the Henry reaction over the catalysts ► High selectivity for nitroalkenes with nearly complete conversion of nitroalkanes ► The catalysts behave as a true heterogeneous catalyst and can be easily recovered.

The deactivation of Pd/C catalyst in the hydrodechlorination of the two chlorofluorocarbons CClF2–CF3 (CFC-115) and CF2Cl2 (CFC-12) into their corresponding hydrofluorocarbons CHF2–CF3 (HFC-125) and CF2H2 (HFC-32) has been systematically investigated. Besides Pd/C catalyst, Pd black was used as a model catalyst in order to exclude the effects of carbon support. The results show that Pd/C catalyst is more efficient for the catalytic hydrodechlorination of CFC-115 than that of CFC-12. From the XRD, TEM, and H2-TPR characterizations, it can be concluded that the deactivation of Pd/C catalysts in the hydrodechlorination of CFC-115 at 673 K, a weight hourly space velocity (WHSV) of 2400 ml g−1(catal.) h−1 and a H2:CFC-115 molar ratio of 2 is mainly attributed to the sintering of the active species Pd particles while the catalyst deactivation in the hydrodechlorination of CFC-12 at 553 K, a WHSV of 1000 ml g−1(catal.) h−1 and a H2:CFC-12 molar ratio of 4 is due to the carbonaceous deposits. Additionally, the deactivation mechanisms of Pd/C catalysts in the two different hydrodechlorination reactions are discussed.Graphical abstractThe sintering of Pd particles leads to the deactivation of Pd/C catalyst in the hydrodechlorination of CFC-115 while the carbonaceous deposits and the formation of palladium carbide are the causes for the catalyst deactivation in the hydrodechlorination of CFC-12.Download high-res image (135KB)Download full-size imageHighlights► The hydrodechlorination of CFC-115 and of CFC-12 over Pd/C catalyst is compared. ► Pd sintering leads to the catalyst deactivation in the hydrodechlorination of CFC-115. ► Carbonaceous deposits cause the catalyst deactivation in the hydrodechlorination of CFC-12. ► The deactivation mechanisms of Pd/C in the two hydrodechlorination reactions are elucidated.

Fe-ZSM-5 zeolites with uniform crystal size and shape were synthesized by a hydrothermal method, and these parent zeolites were desilicated by an alkaline-treatment method to obtain mesoporous Fe-ZSM-5 (meso-Fe-ZSM-5) zeolites. Both Fe-ZSM-5 and meso-Fe-ZSM-5 zeolites were characterized by XRD, N2 adsorption–desorption, ICP-AES, SEM, TEM, UV-vis, and TGA techniques and as catalysts they were used in the direct oxidation of benzene to phenol (BTOP) by N2O as oxidant. The meso-Fe-ZSM-5 catalysts show a much higher catalytic activity and stability, compared to the parent Fe-ZSM-5 catalysts. A comparison study on the uptakes of benzene in the parent and alkali-treated zeolites indicates that the internal mass-transfer limitations of the meso-Fe-ZSM-5 zeolites are significantly improved due to the introduction of intracrystalline mesoporosity, resulting in a better catalytic activity and stability in the BTOP reaction. Desilication in the alkaline medium of Fe-ZSM-5 crystals enables a more efficient utilization of the zeolite in the BTOP reaction that is strongly affected by diffusional limitations.

A highly regio-, chemo-, diastereo- and enantioselective organocatalytic [4 + 1] annulation of 2-halo-1,3-dicarbonyl compounds with Morita–Baylis–Hillman adducts catalyzed by commercially available, low cost quinidine for the preparation of synthetically unique and medicinally multi-functionalized isoxazoline N-oxides with three stereogenic centers including adjacent quaternary and tertiary stereocenters has been developed. Notably, the unexpected product ethyl 2-((tert-butyldimethylsilyl)oxy)-2-(5,5-diacetyl-3-((methylsulfonyl)oxy)-4-phenylisoxazolidin-3-yl)acetate (8) bearing a quaternary stereocenter and two tertiary stereocenters was obtained from the undocumented 5,5-diacetyl-3-(2-ethoxy-1-hydroxy-2-oxoethyl)-4-phenyl-4,5-dihydroisoxazole 2-oxide (4ba).

The sulfoxy or sulfonic acid-functionalized MIL-101 catalyst was prepared by either post-functionalization or pre-modification of the organic linkers with the functionalized ligands, respectively, the latter is the so-called one-pot synthesis method. These catalysts were systemically characterized by XRD, N2 adsorption, acid–base titration, and FT-IR techniques and applied in the liquid-phase esterification of monocarboxylic acids with monohydric alcohols. The results show that the sulfonic acid-functionalized MIL-101 (S-MIL-101) prepared by the one-pot synthesis method possesses a higher catalytic activity in the esterification than its counterpart the sulfoxy acid-functionalized MIL-101 (S/MIL-101) prepared by the post-functionalized method, due to the fact that S-MIL101 has a higher acid loading and a high utilization efficiency of the functionalized acid sites. Moreover, S-MIL-101 is stable to leaching, behaves as a true heterogeneous catalyst, can be easily recovered by filtration, and can be reused five times in succession without any loss of its catalytic activity.

A series of functionalized 2,3-dihydro-1,4-benzoxazines were obtained in moderate to excellent yields via domino [5 + 1] annulations of 2-halo-1,3-dicarbonyl compounds 2 with imines 1 under mild conditions and the application of this method in the synthesis of bioactive analogues, such as functionalized tetracyclic-1,4-benzoxazines which contain two new heterocyclic rings and one quaternary carbon center has also been developed.

Li2ZrO3 nanocrystals with improved CO2 capture properties were synthesized by a citrate sol–gel method. The morphology and structure of the synthesized Li2ZrO3 samples were characterized in detail by SEM, TEM, and XRD techniques. The CO2 capture–regeneration properties of these nanocrystals were investigated by thermogravimetric analysis (TGA) over a wide range of temperatures and of CO2 partial pressures. The nanosized Li2ZrO3 crystallites with a tetragonal phase exhibit a better CO2 capture performance than reported sorbents, exhibiting a faster uptake and a higher, nearly stoichiometric adsorption capacity (∼26 wt.%). Furthermore, the adsorbent shows a good stability, confirmed by capture–regeneration cycles. Based on these excellent properties, application in sorption-enhanced reaction process (SERP) is anticipated.