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BACKGROUND: The tetrahydrofuran–ethanol azeotrope cannot be separated by common distillation, but can be effectively separated by extractive distillation. Extractive distillation can be simulated by Aspen Plus software. The minimum annual cost of the process can be calculated to assess ionic liquid separation ability. The interaction energy can be used to explain the separation mechanism. RESULTS: The non‐random two‐liquid model parameters of ternary mixtures for tetrahydrofuran and ethanol containing tributylmethylammonium acetate or 1‐octyl‐3‐methylimidazolium acetate were obtained. Thermodynamic property databases of tributylmethylammonium acetate, 1‐hexyl‐2,3‐dimethylimidazolium acetate and 1‐octyl‐3‐methylimidazolium acetate were established. Based on the thermodynamic model parameters and properties, the sequential iterative method was used to determine the best operating conditions and minimum total annual cost the of extractive distillation process. The interaction energy was calculated to explain the separation mechanism. CONCLUSIONS: The separation performance of tributylmethylammonium acetate is better than that of 1‐hexyl‐2,3‐dimethylimidazolium acetate or 1‐octyl‐3‐methylimidazolium acetate. The selection and design of the ionic liquids can be conducted in terms of the interaction energy. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

The chemical formula of basic zinc chloride is Zn5(OH)8Cl2 · H2O (denoted as ZHC). It is a new type of zinc source additive, widely used in the feed industry. In this article, micron‐sized hexagonal flake ZHC with a diameter of 10–60 µm is directly prepared by ammonia precipitation method using ZnCl2 as raw material. The products are characterized and analyzed by X‐ray diffraction, scanning electron microscopy, and laser particle size analyzer. The effects of reaction temperature, ammonia flow rate, aging time, and reactant concentration on the product morphology are studied. Under the optimum reaction conditions, the ZnCl2 concentration is 2.0 mol L−1, NH3 flow rate is 300 mL min−1, the reaction time is 1 h, the reaction temperature is 80 °C, and the aging time is 5 h. Lastly, the yield reaches 49.06%. The growth habit of ZHC is theoretically analyzed by the Morphology program. The calculation results are in good agreement with the experimental results. The change of (003) crystal plane exposure caused by temperature is an important reason for the non‐ideality of macroscopic morphology. [ABSTRACT FROM AUTHOR]

BACKGROUND: The binary benzene–n‐propanol azeotrope can be formed in chemical production. Extractive distillation is an important azeotrope separation technology and an ionic liquid is a type of excellent entrainer. Aspen Plus software was used to simulate the extractive distillation process. The separation performance of ionic liquids was evaluated in terms of total annual cost of the extractive distillation process. The separation mechanism of the azeotrope was quantitatively explained using intermolecular interaction energy. RESULTS: The thermodynamic properties databases of 1‐octyl‐3‐methylimidazolium acetate, trioctylmethylammonium acetate and 1‐decyl‐3‐methylimidazolium acetate were established in Aspen Plus software. The extractive distillation process was established through combining the thermodynamic properties of the three ionic liquids and the vapor–liquid equilibrium data of benzene–n‐propanol–ionic liquid. The optimal operating conditions were obtained by minimizing the total annual cost of the separation process through a sequential iterative method. The interaction energy was calculated using density functional theory through Gaussian 09 software and used to explain the principle of the benzene–n‐propanol azeotropic system separation. CONCLUSIONS: 1‐Octyl‐3‐methylimidazolium acetate has the best separation performance among the three ionic liquids. The interaction energy can be used to screen and design ionic liquids in the process of benzene–n‐propanol extractive distillation separation. © 2021 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

In this study, traditional strongly endothermic anaerobic retorting (AR) and relatively novel self‐heating retorting (SHR) processes for oil shale (OS) were investigated and compared in detail. These studies mainly involve the structural and quantitative evolution of organic matters in OS during retorting, including varieties of crystallite parameters, carbon framework structure, amounts of various structural carbons and toxic polycyclic aromatic hydrocarbons, and so on. The obtained results well elucidate some reaction pathways in AR and SHR as well as certain differences between the two retorting processes. Moreover, based on our former work that verifies SHR greatly simplifies retorting operation by in situ generating heat to replace external heat carrier/provision, this study further demonstrates that SHR also alleviates the environmental effect of organic toxic residues as compared to AR. The present study provides some critical results not only for penetrating the reaction mechanism but also for assessing or controlling the environmental impact of both retorting processes. [ABSTRACT FROM AUTHOR]

Oil shale (OS) is a particularly promising alternative fossil fuel source. However, very different from coal, its inorganic mineral content is very high. The organic matters (mainly kerogen) are finely distributed in the inorganic minerals. Therefore, the minerals may affect the processing of OS, whose elucidation is critical to the choice of processing conditions. In this work, different minerals (SiO2, CaCO3, and Al2O3) were added to OS with different mass ratios of OS to mineral, respectively. Then, the thermogravimetric (TG) technique was employed to analyze the reaction behavior of these different OS/mineral mixtures in N2and in air for studying the influence of minerals on the OS pyrolysis in N2(i.e., retorting) and on the OS combustion in air. The results show that CaCO3and Al2O3have a promoting effect on both pyrolysis and combustion of OS, and they can decrease the reaction activation energy of both kinds of processes. However, SiO2has an inhibitive effect and can increase the reaction activation energy for both kinds of processes. It is hoped that the present study can further increase the understanding toward the effect of different minerals on the OS reactions. [ABSTRACT FROM PUBLISHER]

Caustic calcined magnesia (main component is MgO) can be used to produce Mg(OH) 2 by ammonium-circulation method (reaction steps: (1) MgO + 2NH 4 + → Δ Mg 2 + + 2NH 3 ↑ + H 2 O and (2) Mg 2 + + 2NH 3 ↑ + 2H 2 O → Mg(OH) 2 ↓ + 2NH 4 + ; Overall: MgO + H 2 O → Mg(OH) 2 ↓). NH 4 Cl, NH 4 NO 3 and (NH 4 ) 2 SO 4 have exhibited the ability to be used as a circulation medium. In this work, ammonium acetate (NH 4 Ac) was investigated as a circulation medium. The purity of the used caustic calcined magnesia (i.e., MgO content) is 85 wt.%. The results show that NH 4 Ac is a much more efficient circulation medium than NH 4 Cl, NH 4 NO 3 or (NH 4 ) 2 SO 4 is. Step (1) in the ammonium-circulation method can be significantly accelerated if NH 4 Ac is used as the circulation medium. The reason for the high efficiency of NH 4 Ac was also analyzed. By using NH 4 Ac as the circulation medium, rose petal-like Mg(OH) 2 precipitate can be prepared in the presence of polyethylene glycol. The purity of the prepared Mg(OH) 2 is more than 99 wt.%. [ABSTRACT FROM AUTHOR]

A processusing plentiful and inexpensive caustic calcined magnesia(CCM; main component is MgO) to prepare lamellar MH of high purityis described. The process begins with the reaction of MgO in CCM withNH4NO3at ∼100 °C to produce ammoniagas and Mg(NO3)2solution and the subsequentfiltration of Mg(NO3)2solution to remove impurities(e.g., SiO2). Then, the obtained ammonia is introducedinto the Mg(NO3)2solution to produce MH precipitateand NH4NO3. After the MH precipitate is separatedby filtration, the filtrate containing NH4NO3is returned to the initial step. The overall reaction of this processis the hydration of MgO to MH. Therefore, this process is called theapparent-hydration method. This apparent-hydration method overcomesthe disadvantages of the true hydration method, such as the inabilityto remove impurities. A crucial finding is that, because of the presenceof trace SO42–in the obtained Mg(NO3)2solution, a MH product with a narrow particlesize distribution cannot be produced. After removal of the SO42–with Ba(NO3)2,lamellar MH with a narrow particle size distribution can be synthesizedat 120 °C in one step. This work provides a promising route tothe use of CCM to prepare MH. [ABSTRACT FROM AUTHOR]

Abstract: Through-porous steel fiber matrix with high specific surface area and self-support strength was examined as the support of TiO2 film photocatalyst. TiO2 was uniformly and conformally deposited onto the surface of the metal skeleton of the porous steel fiber matrix via atomic layer deposition method so that the porosity as well as gas permeability of the matrix is maintained. For further improving the photocatalytic activity, noble metals (Au and Pt/Pd alloy) were sputtered onto the surface of TiO2 photocatalyst. The photodegradation of methyl orange was used for evaluating the photocatalytic properties. The results show that compared with TiO2 films deposited on flat Si wafers, TiO2 films on the porous support display higher photocatalytic activities, owing to their higher specific surface areas. The photocatalytic activity of TiO2 on porous support was not enhanced by Au, while it was remarkably improved by Pt/Pd. The TiO2 photocatalysts were also analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy. [Copyright &y& Elsevier]

Multi-walled carbon nanotube (MWCNT)/polythiophene (PTh) composites have been prepared by in situ chemical oxidative polymerization. PTh is synthesized onto the sidewalls of the MWCNTs, which play a role as hard templates for PTh to produce one-dimensional nanostructures. The morphology and structures of the MWCNT/PTh composites are characterized by High-resolution transmission electron microscopy, x-ray diffraction, and Fourier transform infrared spectrometry. Their electrical property and thermal stability are determined using vector network analyzer and thermal gravimetric analyzer. Moreover, the mechanism of MWCNT/PTh nanowire formation is described. The studies show that the composites are nanowires with core-shell structure, in which the outer shells and inner cores are formed by PTh and MWCNTs, respectively. The addition of MWCNTs does not change the backbone structure of PTh and affect the amorphous condition of PTh very slightly, however, it improves the electrical conductivity and thermal stability of PTh. [ABSTRACT FROM AUTHOR]

Abstract: Polyaniline(PANi)/Fe3O4 nanocomposites have been prepared via in situ chemical oxidative polymerization directed with cationic surfactant cetyltrimethylammonium bromide (CTAB). The studies show that PANi can coat Fe3O4 nanoparticles. CTAB can produce insoluble substance with initiator of polyreaction, and plays a very important role for the coating of Fe3O4 nanoparticles by PANi. Many Fe3O4 nanoparticles are bald without being coated by PANi when CTAB is replaced by anionic surfactant, so anionic surfactant can not play the role of CTAB. [Copyright &y& Elsevier]

Polymorphism- or morphology-controllable synthesis of CaCO 3 is of significance. Usually only calcite CaCO 3 can be obtained from the ordinary CO 2 -Ca(OH) 2 solution route; the very low solubility of Ca(OH) 2 also causes many defects with this route. The route by CaCl 2 and Na 2 CO 3 exhibits some advantages, but the consumption of Na 2 CO 3 is a deficiency. Therefore, this work studies the precipitation of CaCO 3 with CaCl 2 in NH 3 -CO 2 aqueous solution, which will make the overall reaction “CaCO 3   →   CaCO 3 ” if tracing the origin of the reactants. A main focus of the present work is to elucidate how to obtain various CaCO 3 polymorphs with different morphologies through this synthesis system and the corresponding crystal growth mechanism. The results show that, just by simply regulating the reaction conditions, all three anhydrous CaCO 3 polymorphs with various morphologies (e.g., cubic, lamellar, spherical, needle-like and branched) can be obtained in the absence of any additives. The crystal growth process can be well explained based on either Ostwald ripening or dissolution-recrystallization mechanism, depending on the reaction conditions. In addition, the rare phase transition of metastable vaterite to metastable aragonite can also be obtained from the present synthesis system, besides the usual phase transition of vaterite to the most thermodynamically stable calcite. This work provides the essential theoretical support for further developing a green process for CaCO 3 production by using various calcium-containing carbonate minerals, such as limestone, calcite and dolomite. [ABSTRACT FROM AUTHOR]

Use oxide-supported catalyst in green solvent, hot water : Au is anchored on oxide via Au┄O-M interaction (M = Fe, Ti, etc). Basic aqueous catalytic system may destruct a part of O M bonds into oxygen vacancies and weaken Au/support interaction, causing leaching and aggregation of Au. Three simple methods synergistically improve reusability of catalyst. [Display omitted] • Three facile ways synergistically improve catalyst reusability in green solvent, water. • They raise support stability and Au/support interaction to reduce leaching and aggregation of Au. • Nano supports interact with Au more strongly, and are more stable in hot basic water. • Nano TiO 2 is more stable due to the stronger surface Ti O bond, in line with BOLS theory. Obtaining reusable catalysts and using water as a green solvent still remain huge challenges. Various oxides are frequently used as the support, however, the aqueous catalytic systems, particularly in hot basic water, may decrease their stability and thus cause leaching or aggregation of the supported metal nanoparticles (NPs). In this work, three very simple methods in catalyst preparation are demonstrated to greatly improve the reusability of oxide-supported catalysts in 100 °C basic water, by systematically studying a series of oxides as well as carbons as support of gold (Au) NPs and employing Suzuki-Miyaura cross-coupling (SMCC) reaction as a probe. These methods are prerequisites for obtaining both excellent activity and recyclability. Absence of any of them will badly improve leaching or aggregation of Au NPs. The reasons for the synergistically improved reusability are also elucidated in details. Though it's extremely hard to thoroughly overcome leaching in hot water, this work achieves the application of Au/oxide to SMCC reaction in water with higher utilization efficiency of Au than some reported work in organic solvent or with other supports. The present work can serve as supplementary strategies to assist in designing high-performance oxide-supported catalysts for varieties of similar aqueous systems. [ABSTRACT FROM AUTHOR]

• Isobaric VLE data of ternary for cyclohexane-ethanol containing IL ([N 1,8,8,8 [Ac], [DMIM][AC] or [C16MIM]) were determined at 101.3kPa. • Temperature dependence of some thermophysical properties (heat capacity, viscosity and density) of the three ILs were determined at 101.3kPa and 333.15-363.15 K. • The measured data were well correlated. Some important topics and issues related to possible extractive distillation separation of cyclohexane + ethanol system using ionic liquids (ILs) are presented in this manuscript. Three ILs with acetate anion (methyl-trioctyl-ammonium acetate [N 1,8,8,8 [Ac], 1-decyl-3-methyl-imidazolium acetate [DMIM][Ac] and 1-hexadecyl-3-methyl-imidazolium acetate [C 16 MIM][Ac]) were selected as entrainers. The vapor–liquid phase equilibrium (VLE) data for cyclohexane + ethanol + ILs system were determined at 101.3 kPa and correlated by Wilson and NRTL models. The separation effect of these ILs on the basis of the NRTL model follows this order: [N 1,8,8,8 [Ac] > [DMIM][Ac] > [C 16 MIM][Ac]. The binary VLE data of the cyclohexane-ethanol mixture obtained by this device were compared with previously published data and tested by the Herington thermodynamic consistency test. Temperature dependence of some thermophysical properties (density, viscosity and heat capacity) of these ILs were obtained and correlated within the range of possible distillation operating temperatures. [ABSTRACT FROM AUTHOR]