查找使用阿拉丁产品的科研文献

Measurement and correlation of solubility of 1,3,5-trioxane in binary solvents from (288.15 to 328.15) K

Jie Li,Xinwei Zhang,Quanjie Liu,Zequn Yin

The solubilities of 1,3,5-trioxane were measured by a dynamic method in binary solvents (methanol-water, ethanol-water, isopropanol-water and dimethoxymethane-water) at the temperature range (288.15 to 328.15) K at atmosphere pressure. The solubility increased with increasing of temperature in all case, indicating that the dissolution process of 1,3,5-trioxane was endothermic. In addition, the experimental solubility of 1,3,5-trioxane in binary solvents at different temperatures were correlated by the (CNIBS)/Redlich–Kister model, the modified Apelblat model, Wilson model and NRTL equation. The calculated values were in good agreement with the measured experimental data. The (CNIBS)/Redlich–Kister model and modified Apelblat model were in agreement with the experimental solubility in all the binary solvents. The Wilson model was suitable for the binary solvent of methanol-water and dimethoxymethane-water. NRTL equation was suitable for the all in agreement with the experimental solubility in the binary solvent except the isopropanol–water.

ZnPc-MWCNT/sulfonated poly (ether ether ketone) composites for high-k and electrical energy storage applications

Wenhan Xu,Yunhe Zhang,Gang Yang,Xiang Yu,Jie Liu,Zhenhua Jiang

Volumetric and viscometric properties of amino acids in aqueous maltitol solutions at T = (293.15–323.15) K

Jing Zhang,Chunying Zhu,Youguang Ma

The densities and viscosities of the ternary mixtures of glycine, l -alanine, l -valine, l -threonine and l -arginine in aqueous maltitol solutions were measured at T   =   (293.15–323.15)   K under the atmospheric pressure. The apparent molar volume ( V φ ), the limiting partial molar volume ( V φ 0 ) and the limiting partial molar volume of transfer (Δ tr V φ 0 ) were obtained in terms of the measured density, then the viscosity B -coefficient was further calculated by the least-square method. Meanwhile, the partial molar isobaric expansion ( E 2 0 ), the isobaric thermal expansion coefficient ( α 2 ), the solvation number ( n S ), the free energies of activation per mole of solvent (Δ μ 1 0≠ ) and per mole of solute (Δ μ 2 0≠ ) were also calculated. The volumetric and viscometric properties were analyzed and discussed according to the interactions between amino acids and maltitol molecules based on the co-sphere overlap model and the transition state theory.

ASb2(SO4)2(PO4) (A = H3O+, K, Rb): Layered Structure Containing Ordered Sulfate and Phosphate Anions

Xiao Zhao,Dajiang Mei,Jingli Xu,Yuandong Wu

Three compounds A Sb 2 (SO 4 ) 2 (PO 4 ) ( A = H 3 O + , K, Rb) were obtained from the reactions of Sb 2 O 3 , A 2 CO 3 ( A = Li, Rb) or K 2 SO 4 and NH 4 H 2 PO 4 in H 2 SO 4 (98 %) at 220–250 °C. Their structures were determined by single-crystal X-ray diffraction. All compounds crystallize in the triclinic space group P (no.2) and are isostructural. The crystal structures consist of two-dimensional 2 ∞ [Sb 2 (SO 4 ) 2 (PO 4 )] – anionic layers and alkali cations, which are located between anionic layers. The anionic layers are composed of [SbO 4 ] ψ-trigonal bipyramids, [SbO 5 ] ψ octahedra, [SO 4 ] tetrahedra, and [PO 4 ] tetrahedra. All compounds are characterized by solid state UV/Vis/NIR diffuse reflectance spectra, FT-IR spectroscopy, and Raman spectroscopy.

Liquid–Liquid Equilibrium for Ternary System n-Butanol + n-Hexane + Ethylene Glycol at 298.15–323.15 K

Qingsong Li,Midong Shi,Liping Wang,Gaoyin He,Fan Gan

The liquid–liquid equilibrium (LLE) experiments for n-butanol + n-hexane + ethylene glycol were carried out and LLE data were measured at 298.15, 303.15, 308.15, 313.15, and 323.15 K under atmospheric pressure. The analysis results of the effects of n-butanol content and temperature on extraction showed that high n-butanol content was not favorable for extraction, and temperature had little effect on extraction. Moreover, the NRTL and UNIQUAC models were applied to correlate the LLE data, and the correlated data indicated that the UNIQUAC model showed a better correlation performance.

Thermochemical properties for a series of microporous borophosphates of MI[ZnBP2O8] (MI = Na, K, Rb, Cs)

Pan Liang,Qiu-Yue Kang,Lu Du,Zhi-Hong Liu

Two pure microporous materials, Rb[ZnBP 2 O 8 ] and Cs[ZnBP 2 O 8 ], have been synthesized and characterized by XRD, FT-IR, DTA-TG techniques and chemical analysis. The molar enthalpies of solution of Rb[ZnBP 2 O 8 ] and Cs[ZnBP 2 O 8 ] (s) in 3   mol   ·   dm −3 HCl (aq), of Zn(PO 3 ) 2 (s) in (HCl   +   H 3 BO 3 ) (aq), and of RbCl (s)/CsCl (s) in [Zn(PO 3 ) 2   +   HCl   +   H 3 BO 3 ] (aq) were measured by microcalorimeter at T   =   298.15   K, respectively. With the incorporation of the previously determined enthalpy of solution of H 3 BO 3 (s) in 3   mol   ·   dm −3 HCl (aq), together with the use of the standard molar enthalpies of formation for Zn(PO 3 ) 2 (s), RbCl (s)/CsCl (s), H 3 BO 3 (s), HCl (aq) and H 2 O (l), the standard molar enthalpies of formation of −(3198.5   ±   1.2)   kJ   ·   mol −1 for Rb[ZnBP 2 O 8 ] and −(3212.7   ±   1.2)   kJ   ·   mol −1 for Cs[ZnBP 2 O 8 ] at T   =   298.15   K were obtained on the basis of the appropriate thermochemical cycle. In addition, the molar enthalpy of formation of −(2944.4   ±   1.2)   kJ   ·   mol −1 for [ZnBP 2 O 8 ] − has also been estimated by a group contribution method, which can be used to predict the Δ f H m θ ${\mathrm{\Delta }}_{\text{f}}{H}_{\text{m}}^{\mathrm{\theta }}$ of the other similar borophosphates. Moreover, these data have been further used to compare the thermodynamic stability of this series of borophosphates.

Solubilities of crotonic acid in different organic solvents at several temperatures from (278.15 to 333.15) K

Zheng Cao,Yonghong Hu,Yumei Kai,Jiaojiao Li,Wenbiao Zhi,Wenge Yang

In our study the solubilities of crotonic acid in methanol, ethanol, 2-propanol, 1-butanol, acetic acid, N,N -dimethylformamide, ethyl acetate and acetonitrile were experimentally determined over the temperature range of (278.15–333.15)   K at around 5   K intervals by employing an analytical stirred-flask method. The experimental solubility data were well correlated with the modified Apelblat equation, in different kinds of solvents the values of the sum of MPD were 6.3. The thermodynamic functions were evaluated by two methods and the results were the same. The dissolving process was endothermic, entropy-driving and non-spontaneous. It was necessary to use the experiment data and correlation models in the reaction and purification of crotonic acid.

Facile surfactant-thermal syntheses and characterization of quaternary copper thioantimonates(III) ACu2SbS3 (A = K, Rb, Cs)

Yaying Shen,Chang Liu,Peipei Hou,Mingjia Zhi,Chunmei Zhou,Wenxiang Chai,Qichun Zhang,Yi Liu

Three new quaternary thioantimonates(III) ACu 2 SbS 3 (A = K, Rb, Cs) have been prepared through the surfactant-thermal method. X-ray single crystal diffraction analysis reveals that these three compounds are isostructural and feature a two-dimensional layered structure. Both experimental and theoretical studies confirm they are semiconductors with narrow band gaps. Our results clearly indicated that surfactants, as reaction media, could offer exciting opportunities for exploring novel multinary chalcogenides with diverse crystal structures and interesting physical properties.

A Fragmentation Study on Four Unusual Secoiridoid Trimers, Swerilactones H–K, by Electrospray Tandem Mass Spectrometry

Geng Chang-An,Chen Ji-Jun

Swerilactones H–K ( 1 – 4 ) as four unprecedented secoiridoid trimers represent a new type of natural product, which has attracted much interest of natural chemists due to their novel skeletons and promising bioactivity. In order to well understand their MS fragmentation behaviors, they were investigated by electrospray ionization ion-trap time-of-flight multistage product ion mass spectrometry (ESI-IT-TOF-MS n ) for the first time. The protonated molecules ([M+H] + ) of swerilactones J and K, and deprotonated molecules ([M−H] − ) of swerilactones H, J and K were readily observed in the conventional single-stage mass spectra (MS); however only the [M+Cl] − ion for swerilactone I was obtained in negative mode. Based on the MS n study, the fragmentation pathways of swerilactones H and I in negative mode, and swerilactones J and K in both positive and negative modes were proposed. The neutral losses of H 2 O, CO, CO 2 and C 2 H 4 O moieties are the particular elimination from the precursor ions due to the presence of hydroxyl, δ -lactone and 1- O -ethyl moieties in their structures, of which the retro-Diels–Alder cleavage was the most particular dissociation. The fragment ions at m/z 341 and 291 in negative mode can be considered as the diagnostic ions for secoiridoid trimers. This investigation will provide valuable information for their fast characterization from complicated natural mixtures and extensive understanding their structural architectures.

Efficacy of spilanthol and Acmella oleracea (L.) R. K. Jansen (Asteraceae) extract against Schistosoma mansoni infection

Danilo de Souza Costa,Rayssa A. Cajas,Carla Monteiro Leal,Lara S. Aleixo de Carvalho,Lara Cruz de Souza,Lucas Fukui-Silva,Josué de Moraes,Ademar A. Da Silva Filho

Ethnopharmacological relevance Acmella oleracea (L.) R. K. Jansen, commonly referred to as “Jambu”, is a valuable medicinal plant native to the Amazon regions. Inflorescences of A. oleracea is utilized as local anesthetic properties and for its insecticidal, antiparasitic, and anthelmintic attributes. Aims of this study This study aimed to evaluate the in vitro and in vivo antiparasitic properties of A. oleracea extract and spilanthol (SPL) against Schistosoma mansoni . Materials and methods The ethanolic extract of A. oleracea inflorescences (AoE) was prepared, analyzed by HPLC-DAD, and characterized by UHPLC-HRMS/MS. SPL was isolated from AoE by chromatographic fractionation. The antischistosomal properties of AoE and SPL were evaluated in vitro against adult schistosomes and in preclinical assays using murine models of patent S. mansoni infection. Results Through UHPLC-HRMS/MS analysis, 14 alkamides were annotated in AoE. HPLC-DAD analysis of AoE revealed a peak with a substantial relative area of ∼85%, which was isolated and identified as SPL. AoE and SPL caused mortality of adult schistosomes ex vivo , showing EC 50 values of 32.6 μg/mL and 27.8 μM, respectively, without affected Vero cells or Caenorhabditis elegans . In preclinical studies, the oral administration (400 mg/kg) of AoE and SPL resulted in significant reductions in worm burden of 28% and ∼42%, respectively. Additionally, SPL exhibits remarkable effects on oogram, decreasing egg burden and the number of immature eggs by over 80%, while also promoting significant reductions in hepato- and splenomegaly. Conclusions The research underscores the antischistosomal activity of A. oleracea highlighting the potential of SPL as a lead for the development of new schistosomicidal drugs and encouraging further studies to validate the traditional anthelmintic use of A. oleracea inflorescences.

Engineering Interconnected Nanofluidic Channel in a Hydrogel Supernetwork toward K+ Ion Accelerating Transport and Efficient Sensing

Rui Zhu,Peng Sun,Guofeng Cui,Jie Zhao,Yaoguang Yu

Ion transportation via the mixed mechanisms of hydrogels underpins ultrafast biological signal transmission in nature, and its application to the rapid and sensitive sensing detection of human specific ions is of great interest for the field of medical science. However, current research efforts are still unable to achieve transmission results that are comparable to those of bioelectric signals. Herein, 3D interconnected nanochannels based on poly(pyrrole-co-dopamine)/poly(vinyl alcohol) (P(Py-co-DA)/PVA) supernetwork conductive hydrogels are designed and fabricated as stimuli-responsive structures for K+ ions. Distinct from conventional configurations, which exhibit rapid electron transfer and permeability to biosubstrates, interconnected nanofluidic nanochannels collaborated with the P(Py-co-DA) conductive polymer in the supernetwork conductive hydrogel significantly improve conductivity (88.3 mS/cm), ion transport time (0.1 s), and ion sensitivity (74.6 mV/dec). The faster ion response time is attributed to the synergism of excellent conductivity originating from the P(Py-co-DA) polymer and the electronic effect in the interconnected nanofluidic channels. Furthermore, the supernetwork conductive hydrogel demonstrates K+ ion selectivity relative to other cations in biofluids such as Na+, Mg2+, and Ca2+. The DFT calculation indicates that the small solvation energy and low chemical transfer resistance are the main reasons for the excellent K+ ion selectivity. Finite element analysis (FEA) simulations further support these experimental results. Consequently, the P(Py-co-DA)/PVA supernetwork conductive hydrogels enriched with the 3D interconnected nanofluidic channels developed in this work possess excellent sensing of K+ ions. This strategy provides great insight into efficient ion sensing in traditional biomedical sensing that has not been explored by previous researchers.

Effect of K and Ni Promoters on Mo2C/Al2O3 Catalyst for Higher Alcohols Synthesis from Syngas

Yang Zhi,Luo Mingsheng,Liu Qinglong,Li Chenmeng,Wang Yatao,Li Hongjuan,Yao Lifei

Abstract The direct production of higher alcohols from syngas in a single step remains a great challenge. In this work, a series of K and Ni promoted Mo 2 C/Al 2 O 3 catalysts were prepared by impregnation method to enhance the selectivity of Mo 2 C-based catalysts for the one-step conversion of syngas to higher alcohols. The catalysts were continuously tested under the following conditions: 300°C, 3.0 MPa, velocity—11.50 \({\text{Lg}}_{{{\text{Mo}}}}^{{ - 1}}\) h –1 , H 2 /CO ratio of 2. The catalysts promoted with K and Ni demonstrated the highest total alcohol selectivity of 67.7%. Moreover, the selectivity for total C 2+ alcohols reached as high as 56%, with 37% being ethanol. X-ray diffraction (XRD), hydrogen temperature-programmed reduction (H 2 -TPR) and X-ray photoelectron spectroscopy (XPS) characterization data reveal that K can promote the crystallinity of β-Mo 2 C, lower the catalyst reduction temperature and increase the proportion of high-valent Mo on the catalyst surface. In addition, adding Ni as a promoter to the KMo 2 C/Al 2 O 3 catalyst can generate a synergistic effect to further enhance the catalytic activity and the selectivity of higher alcohols.