查找使用阿拉丁产品的科研文献

Separation of n-propanol - n-propyl acetate azeotropic system by extractive distillation with ionic liquids: COSMO-RS prediction, experimental investigation and quantum chemical calculation

Fan Yang,Tianzhao Wu,Tinghe Song,Qinqin Zhang,Zhigang Zhang

During the preparation of n-propyl acetate (NPAC), an azeotropic mixture of NPAC and n-propanol (NPA) will form inevitably, which is difficult to separate by ordinary distillation. In this work, COSMO-RS model was applied to screen appropriate ionic liquids (ILs) to separate the binary azeotrope of NPAC - NPA. 1-decyl-3-methylimidazolium acetate ([DMIM][Ac]), 1-octyl-3-methylimidazolium acetate ([OMIM][Ac]), and 1-hexyl-3-methylimidazolium acetate ([HMIM][Ac]) were selected as entrainers based on solvent capacity and selectivity. The vapor–liquid equilibrium (VLE) data of the binary system (NPA - NPAC) and the ternary system (NPA - NPAC - IL) were measured at atmospheric pressure. The thermodynamic consistency of VLE data was verified by van Ness test and Wisniak's L-W test. The NRTL (non-random two liquids) model was used to correlate the VLE experimental data and obtained good applicability. The experimental results demonstrated that all three ionic liquids can improve the relative volatility of NPAC to NPA, and the separation effect is more obvious with the increase of ionic liquid content. The separation performance order of three ionic liquids follows: [HMIM][Ac] > [OMIM][Ac] > [DMIM][Ac]. Finally, ESP analysis, mutual penetration analysis, and IGMH analysis plus QTAIM topological analysis were used to explore the mechanism of separation. The analysis results indicate that the interaction between ionic liquids and NPA is stronger than that between ionic liquids and NPAC. In addition, the stronger interaction between [DMIM][Ac] and NPA is due to their strong hydrogen bond (HB) interactions.

Vapor–Liquid Equilibrium Experiment and Thermodynamic Correlation of n-Propanol + n-Propyl Acetate + 1-Ethyl-3-methylimidazolium Acetate and 1-Hexyl-3-methylimidazolium Acetate

Feihu Li,Yidong Gu,Yanli Sun,Dahaun Liu,Qunsheng Li

In the esterification reaction of n-propanol and acetic acid to produce n-propyl acetate, the presence of a mixture of n-propanol and n-propyl acetate is inevitable. However, the system of n-propanol and n-propyl acetate has an azeotropic point, which makes it impossible for conventional distillation to separate the two substances completely. Therefore, 1-ethyl-3-methylimidazolium acetate ([EMIM][OAC]) and 1-hexyl-3-methylimidazolium acetate ([HMIM][OAC]) were selected as entrainers to conduct the vapor–liquid equilibrium experiment of n-propanol + n-propyl acetate + [EMIM][OAC] and n-propanol + n-propyl acetate + [HMIM][OAC] at atmospheric pressure in this study. The experimental data were regressed by the NRTL model and UNIFAC-Lei model. NRTL model was in better agreement with the experimental data. The results showed that both [EMIM][OAC] and [HMIM][OAC] could separate the n-propanol + n-propyl acetate system, and [EMIM][OAC] showed the enormous separation potential of ionic liquids based on [OAC]− as anions for the azeotropic system.

Mechanical Properties and Thermal Degradation Kinetics of a Novel Thermally Stable Thermoplastic Poly(ester-ether) Elastomer Containing N′N-Bis(2-carboxymethyl) Pyromellitimide Unit

Shaojian Lin,Jiaojiao Shang,Jianwu Lan,Ronghui Guo,Xia Huang,Wen He

Preparation, Mechanical Properties and Thermal Degradation Kinetics of a Novel Poly(ester-ether-imide) Elastomer Based on N′,N-Bis(2-hydroxyethyl)-Pyromellitimide Unit

Shaojian Lin,Jianwu Lan,Ronghui Guo,Jiaojiao Shang,Wen He

Ban+2Znn(BO3)n(B2O5)Fn (n = 1, 2): new members of the zincoborate fluoride series with two kinds of isolated B–O units

Miriding Mutailipu,Xin Su,Min Zhang,Zhihua Yang,Shilie Pan

Two new members of zincoborate fluoride series Ban+2Znn(BO3)n(B2O5)Fn (n = 1, 2), namely, Ba3Zn(BO3)(B2O5)F and Ba4Zn2(BO3)2(B2O5)F2 were firstly synthesized as high-quality single crystals via a high-temperature solution method by adjusting the molar ratios of reactants. They were structurally determined by single-crystal X-ray diffraction and their structures can be regarded as three dimensional (3D) framework stacking of 2∞[Zn2B6O16]10− layers for Ba3Zn(BO3)(B2O5)F and 2∞[Zn2B4O8O5/2O1/3]17/3− layers for Ba4Zn2(BO3)2(B2O5)F2. To the best of our knowledge, the two title compounds are the first examples of two kinds of isolated B–O groups that coexist in one zincoborate halide. The structure comparisons were carried out among all the available anhydrous-zincoborates, and it is interesting to conclude that about 80% of zincoborates contain isolated B–O clusters and notably the molar ratio of cation/boron (A/B) affects the polymerization of isolated B–O configuration. What's more, the first-principles calculations, infrared spectra, and UV-vis-NIR diffuse reflectance spectra of title compounds have also been performed.

Synergistic regulation of surface O/N active sites and local conjugation in N-doped carbonized polymer dots for smartphone-assisted dual-mode sensing of Hg2+

Tao Li,Weitao Wang,Boyang Dou,Shudie Shen,Wenli Zhao,Yanfei Wang,Xiaoyu Zhao,Botao Teng,Liang Zhu

The development of portable, sensitive, and interference-resistant platforms for on-site Hg 2+ detection in aquatic food samples remains highly desirable for food safety monitoring. Herein, a smartphone-assisted fluorescence/colorimetric dual-mode sensing platform was constructed based on N-doped carbonized polymer dots (N-CPDs). The N-CPDs were prepared from ethylenediaminetetraacetic acid and m -phenylenediamine via one-step crosslinking polymerization. By regulating surface O/N active sites and local conjugated structures, the N-CPDs exhibited fluorescence quenching and colorimetric responses toward Hg 2+ without additional responsive reagents. The limits of detection were 40.91 and 38.97 nM for the fluorescence and colorimetric modes, respectively. Structural characterization and quantum chemical calculations indicated that the matching between key oxygen-containing recognition sites and local conjugated structures is critical to the sensing performance. Mechanistic analysis further revealed Hg 2+ -induced static fluorescence quenching and a coordination-driven colorimetric response. Coupled with smartphone-based RGB analysis, the platform enabled portable quantitative detection of Hg 2+ in aquatic food samples, including fish, shrimp, crab, and seaweed. The recoveries were 90.11–108.88%, with RSDs below 4.98%, and the results agreed well with ICP-OES measurements. This work provides an effective strategy for constructing high-performance CPD-based dual-mode sensing platforms and offers a promising tool for portable and reliable Hg 2+ monitoring in real food samples.

Synergistic effect of p-type semiconductor n-Co3O4@C-N on the flame retardancy, smoke suppression, and toxicity reduction of linear low-density polyethylene composites

Jiaqi Geng,Zhichao Tian,Ruiping Wang,Junxiu Liu,Miaojun Xu,Huiying Wen,Mingyang Zhu,Bin Li

Linear low-density polyethylene (LLDPE) is flammable and produces severe molten droplets and toxic smoke, posing a great threat to life and property safety. To address these challenges, ZIF−67-derived nano-carbon-nitrogen-coated Co 3 O 4 (n-Co 3 O 4 @C-N) was synthesized and employed as a synergist for an intumescent flame retardant (IFR) in LLDPE. When IFR/n-Co 3 O 4 @C-N was introduced, LLDPE composites achieved a UL−94 V−0 rating and the limiting oxygen index of 26.8%. Cone calorimeter test results further demonstrated that the total heat release of LLDPE/IFR/n-Co 3 O 4 @C-N−3 decreased by 23.2% compared with pure LLDPE, indicating remarkable suppression of fire intensity. Compared with LLDPE/IFR and LLDPE/commercial-Co 3 O 4 , LLDPE/IFR/n-Co 3 O 4 @C-N−3 exhibited a reduction in total smoke production by 50.3% and 37.2%. The high specific surface area of n-Co 3 O 4 @C-N facilitates sufficient contact with the polymer matrix, enhancing catalytic carbonization and forming a robust graphitized char layer. Furthermore, as a p-type semiconductor, n-Co 3 O 4 @C-N has a narrower band gap, reducing the energy required for electron transition, and its higher hole concentration helps to oxidize more CO to low-toxicity CO 2 , thereby lowering the concentration of toxic gases. This study presents a promising strategy to fabricate flame-retardant, smoke-suppressing, and low-toxic LLDPE composites, thus effectively overcoming the existing technical limitations in wire and cable application fields.

Synergistically Coupled CoFe Core–Shell Nanoparticles and Fe–N x Motifs in N,S,P-Doped Hierarchical Carbon for Rechargeable Zinc–Air Batteries

Balamurali Ravichandran,Soujanya Prakash Bammanalli,Muthu Austeria P,Sabarinathan Ravichandran,Huiyuan Liu,Weiqi Zhang,Narayanamoorthy Bhuvanendran,Huaneng Su

Abstract Rechargeable zinc–air batteries (ZABs) require efficient and durable bifunctional oxygen electrocatalysts to accelerate both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, we report a hierarchical N, S, and P co-doped carbon catalyst (CoFe/NSP-HC) featuring CoFe core–shell alloy nanoparticles and Fe–Nx coordination motifs, synthesized through a pyrolysis strategy using heteroatom-enriched g-C3N4 as both template and dopant source. Structural characterization reveals a hierarchical porous architecture with uniformly distributed heteroatoms, strong metal–support interactions, and a well-defined Co-rich core/Fe-rich shell configuration. The synergistic integration of CoFe alloy interfaces, Fe–Nx coordination sites, and a defect-rich carbon framework effectively modulates the electronic structure and optimizes the adsorption/desorption behavior of oxygenated intermediates. Consequently, the optimized CoFe/NSP-HC catalyst exhibits bifunctional activity with an ORR half-wave potential of 0.82 V and an OER overpotential of 260 mV at 10 mA cm–2, delivering a low bifunctional potential gap (ΔE) of 0.67 V. Furthermore, the catalyst demonstrates robust electrochemical durability, maintaining stable ORR/OER performance after prolonged cycling. Density functional theory calculations reveal that Fe–Nx sites and Fe-based interfacial centers provide favorable reaction energetics for oxygen electrocatalysis, while Co species contribute to electronic modulation and kinetic enhancement. When employed as the air cathode in a rechargeable ZAB, CoFe/NSP-HC delivers a peak power density of 158.7 mW cm–2 and long-term cycling stability exceeding 350 h. This work provides an effective strategy for constructing multi-component electrocatalysts with synergistically engineered active sites for advanced metal–air energy storage systems.

An Overlooked Source of Nitrosamines from Tire-Derived Amine Additives: The Contribution and Transformation Mechanism of N-Isopropyl-N′-phenyl-p-phenylenediamine (IPPD) during Chlorination

Chenglin Liu,Zhong Zhang,Siyuan Xiong,Sheng Wan,Zeyu Chen,Yao Cheng,Bintian Zhang,Xin Yang,Guomao Zheng

Identification of disinfection byproducts (DBPs) precursors remains a longstanding challenge due to the complexity of contaminated source water. Tire wear particles (TWPs) can be an overlooked source of DBPs precursors. To figure out the specific amine additives in tire rubber serving as potential nitrosamine precursors during chlorination, six frequently measured tire-derived amine additives, including N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD), N-isopropyl-N′-phenyl-p-phenylenediamine (IPPD), N-cyclohexyl-N′-phenyl-p-phenylenediamine (CPPD), N,N′-dicyclohexylurea (DCU), diphenylamine (DPhA), and N,N′-dicyclohexylamine (DCHA), were selected to simulate their degradation processes, and their DBPs formation potentials were evaluated under various water matrices. IPPD was found to have a high molar yield of N-nitrosodimethylamine (NDMA, up to 8%), while 6PPD exhibited a lower molar yield (∼0.1%) with the molar ratio of chlorine-to-ammonium nitrogen (Cl2:N = 2) and disinfectant-to-precursor (D/P = 10). Suspect and target screening approaches were further applied to identify the transformation products of IPPD, and the formation pathway of NDMA via IPPD was proposed. Furthermore, we assessed NDMA formation from IPPD in simulated TWP leachates through chlorination experiments in the presence of ammonia, which revealed that IPPD contributed up to 24% of the total NDMA formed. This study offers new insights into the previously overlooked source of nitrosamines from tire-derived amine additives.

Experimental and modeling study of the autoignition for diesel and n-alcohol blends from ethanol to n-pentanol in shock tube and rapid compression machine

Sixu Wang,Yueying Liang,Jizhen Zhu,Mohsin Raza,Jing Li,Liang Yu,Yong Qian,Xingcai Lu

The ignition delay times (IDTs) of n-alcohol/diesel blends were measured in a heated shock tube (ST) and a heated rapid compression machine (RCM). Three sets of blends were formulated to investigate the effect of n-alcohol (the volume ratio of n-alcohol/diesel being 20%/80% for four blends), cetane number (CN = 43, the volume ratio of n-alcohol/diesel being 20%/80% ethanol/diesel, 20.5%/79.5% n-propanol/diesel, 23.5%/76.6% n-butanol/diesel, 25.8%/74.2% n-pentanol/diesel), and oxygen content (mass fraction of oxygen w O2  = 6.65%, the volume ratio of n-alcohol/diesel being 20%/80% ethanol/diesel, 25.6%/74.4% n-propanol/diesel, 31.4%/68.6% n-butanol/diesel, 37.2%/62.8% n-pentanol/diesel) on the autoignition characteristics. In the RCM temperature region, the IDTs decrease with increasing n-alcohol chain length from ethanol to n-pentanol for all three sets of blends, while those in the ST temperature region show indiscernible variations. Interestingly, the intersection of IDTs for ethanol/diesel blend with other n-alcohol/diesel blends is observed when the temperature is below ~700 K. A recently-released detailed mechanism from the CRECK modeling group was used to predict the experimental results. The simulations show relatively good agreement with high-temperature (HT) ignition data, while the mechanism pronouncedly overpredicts the reactivity of blends at low-to-intermediate temperatures. Sensitivity analyses at three temperatures of 675 K, 800 K, and 1300 K were conducted to identify the dominant reactions during the autoignition of 20% n-alcohol/80% diesel blends and to kinetically elaborate and discuss the discrepancies between simulations and experiments. At the end, a preliminary mechanism tune-up was carried out grounded on the sensitivity analyses. The improved mechanism regains its predictive ability for IDTs of 20% n-butanol/80% diesel blend at RCM temperatures, while fails to precisely simulate the remaining three blends.

Liquid–Liquid Equilibrium Measurement for the Separation of n-Propanol + n-Propyl Acetate Using Imidazolium-Based Ionic Liquids with Different Anions at T = 303.15 K

Fan Yang,Qinqin Zhang,Hua Xin,Tianzhao Wu,Zhigang Zhang

Separating the mixture of the target product n-propyl acetate (NPAC) and the unreacted reactant n-propanol (NPA) is necessary during the production of NPAC. NPA and NPAC cannot be separated by simple distillation because the two could form an azeotrope under atmospheric pressure. Liquid–liquid extraction is an energy-saving and environment-friendly method for separating azeotropic mixtures. Ionic liquids (ILs) are promising alternatives to conventional extractants for separating azeotropes due to the advantages of designability and negligible vapor pressure. In this study, the liquid–liquid equilibrium (LLE) data for the ternary systems of NPAC + NPA + 1-butyl-3-methylimidazolium dihydrogen phosphate ([BMIM][H2PO4]) or 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) or 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) were determined at 303.15 K and 101.3 kPa. The accuracy of the experimental LLE data was checked by the Bachman, Hand, and Othmer–Tobias equations. The selectivity and partition coefficient were calculated to evaluate the extraction capability of the selected extractants. The experimental LLE data were correlated with the nonrandom two-liquid model, and the binary interaction parameters were regressed. Finally, the separation mechanism of the three ILs was explored through σ-profile analysis.

Co-deposition of nanocrystalline Co–Mo catalysts with a new fluffy microstructure for hydrogen evolution reaction based on N, N-dimethylformamide and ethylene glycol system

Xinkuai He,Zhousi Hu,Jingjing Yang,Ruqing Guo,Luye Wu

The co-deposition behavior of Co(II) and Mo(VI) in N,N-dimethylformamide and ethylene glycol system is observed. The result implies that Co–Mo co-deposition is typical induced deposition, while containing ordinary deposition process . Mo(VI) species in the system can suppress the reduction of Co(II) and its effect can be improved as the increase of Mo(VI) concentration, however, Co(II) species can promote the reduction of Mo(VI) and the effect can also be improved as the increase of Co(II) concentration. SEM micrographs indicate that all these films exhibit a fibrous surface morphology with a new fluffy microstructure. XRD pattern reveals that the Co–Mo film is a Mo solid solution in Co and its average size of crystalline grain is 9.5 nm. In addition, the electrocatalytic activity for hydrogen evolution reaction (HER) on these Co–Mo films is investigated. These results indicate that its electrocatalytic activity can be improved as Mo content increases from 1.02 to 2.84 wt% and the prepared Co–Mo film with 2.84 wt% Mo presents a high electrocatalytic activity and stability for HER with an overpotential of 81 mV at 10 mA cm −2 .