Crystalline porous ionic salts assembled from polyoxometalates and cationic capsule for the selective photocatalytic aerobic oxidation of aromatic alcohols to aldehydes

Crystalline porous ionic salts(CPISs) represent a new type of porous materials constructed by electrostatic interaction, however, synthesis of CPISs bearing pre-designed functionality while exhibiting permanent porosity is still challenging. Herein we report the facile synthesis of a series of CPISs 1-3 built from photocatalytic-active polyoxometalate(POM) clusters and cationic Zr-based capsules, which showed open porous frameworks with BET surface area up to 33 m^(2)/g and high activity and selectivity for photodriven aerobic oxidation of alcohols to aldehydes. Compared with the pristine POM cluster {W10}, 1 can promote the reaction in much higher efficiency due to the concerted catalysis of preinstalled {W10} and Zr-based capsule together with open channels. This work highlights the advantage of CPISs as porous heterogeneous catalysts in organic transformation, and may shed light on the rational design of more delicate CPISs-derived functional materials.

Synthesis and kinetics of 2,5-dicyanofuran in the presence of hydroxylamine ionic liquid salts

2,5-Dicyanofuran(DCF)is an important biomass-derived platform compound primarily used to prepare bio-based adiponitrile,which is the key precursor for the synthesis of nylon 66 and 1,6-hexanediisocyanate(HDI).In this study,one-pot,green and safe synthesis of DCF from 2,5-diformylfuran(DFF)and hydroxylamine ionic liquid salts was proposed.Eco-friendly hydroxylamine ionic liquid salts were used as the nitrogen source.Ionic liquid exhibited three-fold function of cosolvent,catalysis and phase separation.The conversion of DFF and yield of DCF reached 100%under the following optimum reaction conditions:temperature of 120℃ for 70 min,volume ratio of paraxylene:[HSO_(3)-b-Py]
HSO4 of 2:1,and molar ratio of DFF:(NH_(2)OH)_(2)
[HSO_(3)-b-Py]
HSO4 of 1:1.5.The reaction mechanism for the synthesis of DCF was proposed,and the kinetic model was established.The reaction order with respect to DFF and intermediate product 2,5-diformylfuran dioxime(DFFD)was 1.06 and 0.16,and the reaction activation energy was 64.07 kJ·mol^(-1) and 59.37 kJ·mol^(-1) respectively.After the reaction,the ionic liquid was easy to separate,recover and recycle.

Thermochemical properties and thermokinetic behavior of energetic triazole ionic salts

The properties of dissolution in different solvents,the specific heat capacity and thermal decomposition process under the non-isothermal conditions for energetic triazole ionic salts 1,2,4-triazolium nitrate(1a),1,2,3-triazolium nitrate(1b),3,4,5triamino-1,2,4-triazolium nitrate(2a),3,4,5-triamino-1,2,4-triazolium dinitramide(2b)were precisely measured using a Calvet Microcalorimeter.The thermochemical equation,differential enthalpies of dissolution(△difH m ),standard molar enthalpies of dissolution(△difH m ),apparent activation energy(E),pre-exponential constant(A),kinetic equation,linear relationship of specific heat capacity with temperature over the temperature range from 283 to 353 K,standard molar heat capacity(C p,m)and enthalpy,entropy and Gibbs free energy at 283–353 K,taking 298.15 K as the benchmark for 1a,1b,2a and 2b were obtained with treating experimental data and theoretical calculation method.The kinetic and thermodynamic parameters of thermal decomposition reaction,critical temperature of thermal explosion(Tb),self-accelerating decomposition temperature(TSADT)and adiabatic time-to-explosion(t)of 1a,1b,2a and 2b were calculated.Their heat-resistance abilities were evaluated.Information was obtained on the relation between molecular structures and properties of 1a,1b,2a and 2b.

Preparation of Ionic Liquids Immobilized on FMIL-101 Catalysts for Conversion of CO_(2)to Propylene Carbonate

Metal-organic frameworks(MOFs)have attracted considerable research attention as a new type of porous material for catalytic applications.Herein,2,5-dihydroxyterephthalic acid was proposed to replace conventional terephthalic acid and reacted with chromic nitrate nonahydrate to synthesize a functional metal–organic framework(FMIL-101).This was then used to immobilize various compound ionic liquids to prepare three ionic liquids immobilized on FMIL-101 catalysts,namely,FMIL-101-[HeMIM]Cl/(ZnBr_(2))_(2),FMIL-101-[CeMIM]Cl/(ZnBr_(2))_(2),and FMIL-101-[AeMIM]Br/(ZnBr_(2))_(2).After characterization by Fourier-transform infrared spectroscopy,X-ray diffraction,ultraviolet spectroscopy,thermogravimetry,specific surface area analysis,and scanning electron microscopy,the catalysts were used to mediate cycloaddition reactions between carbon dioxide(CO_(2))and propylene oxide.The effects of reaction temperature,reaction pressure,reaction time,and catalyst dosage on the catalytic performance were investigated.The results revealed that the FMIL-101-supported CIL catalysts afforded the target product propylene carbonate with good catalytic performance and thermal stability.The optimal catalyst,FMIL-101-[CeMIM]Cl/(ZnBr_(2))_(2),displayed a propylene oxide conversion of 98.64%and a propylene carbonate selectivity of 96.63%at a reaction temperature of 110℃,a reaction pressure of 2.0 MPa,a catalyst dosage of 2.0%relative to propylene oxide,and a reaction time of 2.5 h.In addition,the conversion and selectivity of the catalyst decreased slightly after four cycles.Additionally,the catalyst decreased slightly in catalytic performance after being recycled four times.

Lithium Ion Extraction from the High Ration Mg/Li Salt Lake Brine with Ionic Liquid in Triisobutyl Phosphate and Kerosene

1 Introduction As the lightest metal with the unique properties of energy production and storage,lithium is regarded as the new century energy metal.Lithium and its compounds were widely used in various industrial fields,especially in

Expeditious Coordination-Driven Construction of Hierarchically Nanoporous Barium Salts

Organic moieties-derived salts with permanent porosity and polarized channels have shown unique features and attractive performance in the field of adsorption,separation,and conduction.However,state-of-the-art organic salts generally rely on ionic interaction and hydrogen bonding formation to maintain the porous channels.The synthesis of organic moiety-derived saltswith permanent accessible pores even after removal of the trapped guest molecules,and without the constraint of hydrogen bonding formation still remains a great challenge.Herein,we present an expeditious construction pathway to generate hierarchically nanoporous barium salts without hydrogen bonding formation.The strong ionic interaction of the bariumcation and sulfonate anions led to rapid reaction equilibrium(∼2 min),affording diverse barium-derived ionic polymer(Ba-IP)with permanent porosity and highly polarized channels.The produced Ba-IP materials with abundant cations and anions displayed high CO_(2)/N2 and CO_(2)/CH_(4)separation performance,with the selectivities reaching up to 89.5 and 280,respectively,at 273 K,surpassingmost of the organic polymers functionalized by ionic moieties.

An experimental study of salt expansion in sodium saline soils under transient conditions

Salt expansion in sulfate saline soils that are widely distributed in northwestern China causes serious infrastructural damages under low-temperature conditions. However, the mechanism of salt expansion under low temperatures is not clear. In this study, we conducted a series of cooling experiments combined with salt crystallization to study this mechanism, and employed an ionic model to calculate the supersaturation ratio of the solution. During the experiments, the strength and the process of salt expansion were examined under different cooling rates and various crystal morphologies. The relationship between temperature and supersaturation ratio under transient conditions was also considered. Results indicate that the initial supersaturation ratio of a sodium sulfate solution is closely related to environmental conditions, and that this ratio decreases with slowing the cooling rates and stabilizing the crystal forms. Higher initial supersaturation ratios lead to an increased non-steady-state zone, resulting in less salt expansion. On the other hand, chloride ion content has a distinct influence on the crystallization supersaturation ratio of the sodium sulfate solution, and higher chloride ion content can inhibit salt expansion in sodium saline soils. These findings help explain salt expansion mechanisms in complex conditions such as seasonally frozen soils, and thus help search for improved methods of preventing salt expansion in sulfate saline soils.

Synthesis and properties of energetic salts based on 3-nitro-5-nitroimino-1,2,4-oxadiazole

A series of 3-nitro-5-nitroimino-1,2,4-oxadiazole-based energetic salts were synthesized from 3-nitro-5-nitroimino-1,2,4-oxadiazole anion and nitrogen-rich cations. They were fully characterized by IR,elemental analysis and NMR spectroscopy. The structure of triaminoguanidinium salt（1-e） was confirmed by single crystal X-ray diffraction. All salts showed good thermal stability with decomposed temperature ranging from 155 8C to 258 8C, and positive heats of formation from 226.0 k J/mol to554.1 k J/mol. Thus, the theoretic detonation pressure was predicted from 28.70 GPa to 37.60 GPa and velocities from 8526 m/s to 9354 m/s. Among them, guanidinium salt（1-c） exhibited both high decomposition temperature（258 8C） and detonation velocity（9319 m/s）.