The Calculation of Both Electrostatic and Van der Waals Effects to Probe the Efficiency of Solvent Extraction of Heterocyclic Aromatics from Heavy Oil.

Due to the complex composition and similar structure, the extraction denitrification of aromatic rich oil is faced with the contradiction problem of denitrification efficiency and aromatic loss which cannot be efficiently solved by experiments. However, the complex interactions involved can be analyzed from the perspective of calculation, and the prediction criteria and methods are proposed. Based on rigorous density functional theory calculation data, Simple models based on electrostatic potential (ESP) and Van der Waals potential (VdWP)-based calculations were established and validated. The twofold model provided the best prediction for interactions between extractants and nitrogen compounds and between extractants and aromatics, which determines denitrification efficiency and aromatic loss, respectively, due to the most complete description of both electrostatic and VdW force. This provides a powerful tool for evaluating the non-covalent interactions and thence tuning the efficiency of the separation process. Thus, high denitrification efficiency (43.2~66.3 %) and moderate aromatic loss (1.7~4.4 %) were obtained using screened deep eutectic solvents (DESs). This ideal observation provided the potential for mild hydrodesulfurization and manufacture of high-grade carbon materials.

Metals and non-metals in the periodic table.

The demarcation of the chemical elements into metals and non-metals dates back to the dawn of Dmitri Mendeleev's construction of the periodic table; it still represents the cornerstone of our view of modern chemistry. In this contribution, a particular emphasis will be attached to the question 'Why do the chemical elements of the periodic table exist either as metals or non-metals under ambient conditions?' This is perhaps most apparent in the p-block of the periodic table where one sees an almost-diagonal line separating metals and non-metals. The first searching, quantum-mechanical considerations of this question were put forward by Hund in 1934. Interestingly, the very first discussion of the problem-in fact, a pre-quantum-mechanical approach-was made earlier, by Goldhammer in 1913 and Herzfeld in 1927. Their simple rationalization, in terms of atomic properties which confer metallic or non-metallic status to elements across the periodic table, leads to what is commonly called the Goldhammer-Herzfeld criterion for metallization. For a variety of undoubtedly complex reasons, the Goldhammer-Herzfeld theory lay dormant for close to half a century. However, since that time the criterion has been repeatedly applied, with great success, to many systems and materials exhibiting non-metal to metal transitions in order to predict, and understand, the precise conditions for metallization. Here, we review the application of Goldhammer-Herzfeld theory to the question of the metallic versus non-metallic status of chemical elements within the periodic system. A link between that theory and the work of Sir Nevill Mott on the metal-non-metal transition is also highlighted. The application of the 'simple', but highly effective Goldhammer-Herzfeld and Mott criteria, reveal when a chemical element of the periodic table will behave as a metal, and when it will behave as a non-metal. The success of these different, but converging approaches, lends weight to the idea of a simple, universal criterion for rationalizing the instantly-recognizable structure of the periodic table where …the metals are here, the non-metals are there … The challenge of the metallic and non-metallic states of oxides is also briefly introduced. This article is part of the theme issue 'Mendeleev and the periodic table'.

Preparation and characterization of Dendrobium officinale powders through superfine grinding.

BACKGROUND: Dendrobium officinale has been used in China for several thousand years as a health food and has become one of the most expensive tea materials worldwide as a result of extremely scarce resources in the wild and an increasing demand. Hence, it is very important to improve the depth and width of its application. In the present study, the physico-chemical, surface chemistry and thermal properties of micron range particles and coarse particles prepared by superfine grinding and shear pulverization were investigated. RESULTS: As the particle size decreased, the specific surface area of D. officinale powders increased significantly. Microscopy observations confirmed that superfine grinding effectively changed the original structure of D. officinale. The Fourier transform infrared spectroscopy spectra depicted the characteristic bands shifted in terms of absorbance and/or wave number as the powder particle size decreased. The crystallinity and intensity of the crystal peaks of D. officinale powders increased as the particle size decreased. Moisture sorption isotherms suggested that superfine powders were more unstable as a result of the increase in surface area, as well as the exposure of polar groups. CONCLUSION: The results of the present study suggest that superfine grinding may provide new methods of processing for D. officinale with respect to further enhancement of its application value. © 2017 Society of Chemical Industry.

Protective Effects of Lepidium meyenii (Maca) Aqueous Extract and Lycopene on Testosterone Propionate-Induced Prostatic Hyperplasia in Mice.

The inhibitory effect of maca extractant, lycopene, and their combination was evaluated in benign prostatic hyperplasia (BPH) mice induced by testosterone propionate. Mice were divided into a saline group, solvent control group and testosterone propionate-induced BPH mice [BPH model group, solvent BPH model group, benzyl glucosinolate group (1.44 mg/kg), maca group (60 mg/kg), lycopene treated (15, 5, and 2.5 mg/kg), maca (30 mg/kg) combine lycopene treated (7.5, 2.5, and 1.25 mg/kg), and finasteride treated]. Benzyl glucosinolate was used in order to evaluate its pharmacological activity on BPH to find out whether it is the major active component of maca aqueous extract. Finasteride was used as positive control. The compounds were administered once for 30 successive days. Compared with solvent BPH model group, BPH mice fed with maca (30 mg/kg) and lycopene (7.5 mg/kg) combination exhibited significant reductions in the prostatic index, prostatic acid phospatase, estradiol, testosterone, and dihydrotestosterone levels in serum. They also had similar histological compared with those aspects observed in the mice in the solvent control group. The results indicated that combination of maca and lycopene synergistically inhibits BPH in mice. Copyright © 2017 John Wiley & Sons, Ltd.

Rapid Production of High-Purity Hydrogen Fuel through Microwave-Promoted Deep Catalytic Dehydrogenation of Liquid Alkanes with Abundant Metals.

Hydrogen as an energy carrier promises a sustainable energy revolution. However, one of the greatest challenges for any future hydrogen economy is the necessity for large scale hydrogen production not involving concurrent CO2 production. The high intrinsic hydrogen content of liquid-range alkane hydrocarbons (including diesel) offers a potential route to CO2 -free hydrogen production through their catalytic deep dehydrogenation. We report here a means of rapidly liberating high-purity hydrogen by microwave-promoted catalytic dehydrogenation of liquid alkanes using Fe and Ni particles supported on silicon carbide. A H2 production selectivity from all evolved gases of some 98 %, is achieved with less than a fraction of a percent of adventitious CO and CO2 . The major co-product is solid, elemental carbon.

Anti-obese effect of glucosamine and chitosan oligosaccharide in high-fat diet-induced obese rats.

OBJECTIVE: This study is to evaluate the anti-obese effects of glucosamine (GLC) and chitosan oligosaccharide (COS) on high-fat diet-induced obese rats. METHODS: The rats were randomly divided into twelve groups: a normal diet group (NF), a high-fat diet group (HF), Orlistat group, GLC high-, middle-, and low-dose groups (GLC-H, GLC-M, GLC-L), COS1 (COS, number-average molecular weight ≤1000) high-, middle-, and low-dose groups (COS1-H, COS1-M, COS1-L), and COS2 (COS, number-average molecular weight ≤3000) high-, middle-, and low-dose groups (COS2-H, COS2-M, COS2-L). All groups received oral treatment by gavage once daily for a period of six weeks. RESULTS: Rats fed with COS1 gained the least weight among all the groups (P < 0.01), and these rats lost more weight than those treated with Orlistat. In addition to the COS2-H and Orlistat groups, the serum total cholesterol (CHO) and low-density lipoprotein cholesterol (LDL-C) levels were significantly reduced in all treatment groups compared to the HF group (P < 0.01). The various doses of GLC, COS1 and COS2 reduced the expression levels of PPARγ and LXRα mRNA in the white adipose tissue. CONCLUSIONS: The results above demonstrated that GLC, COS1, and COS2 improved dyslipidemia and prevented body weight gains by inhibiting the adipocyte differentiation in obese rats induced by a high-fat diet. Thus, these agents may potentially be used to treat obesity.

Advances in the Study of the Antiatherogenic Function and Novel Therapies for HDL.

The hypothesis that raising high-density lipoprotein cholesterol (HDL-C) levels could improve the risk for cardiovascular disease (CVD) is facing challenges. There is multitudinous clear clinical evidence that the latest failures of HDL-C-raising drugs show no clear association with risks for CVD. At the genetic level, recent research indicates that steady-state HDL-C concentrations may provide limited information regarding the potential antiatherogenic functions of HDL. It is evident that the newer strategies may replace therapeutic approaches to simply raise plasma HDL-C levels. There is an urgent need to identify an efficient biomarker that accurately predicts the increased risk of atherosclerosis (AS) in patients and that may be used for exploring newer therapeutic targets. Studies from recent decades show that the composition, structure and function of circulating HDL are closely associated with high cardiovascular risk. A vast amount of data demonstrates that the most important mechanism through which HDL antagonizes AS involves the reverse cholesterol transport (RCT) process. Clinical trials of drugs that specifically target HDL have so far proven disappointing, so it is necessary to carry out review on the HDL therapeutics.

Solution combustion synthesis: the relevant metrics for producing advanced and nanostructured photocatalysts.

The current developments and progress in energy and environment-related areas pay special attention to the fabrication of advanced nanomaterials via green and sustainable paths to accomplish chemical circularity. The design and preparation methods of photocatalysts play a prime role in determining the structural, surface characteristics and optoelectronic properties of the final products. The solution combustion synthesis (SCS) technique is a relatively novel, cost-effective, and efficient method for the bulk production of nanostructured materials. SCS-fabricated metal oxides are of great technological importance in photocatalytic, environmental and energy applications. To date, the SCS route has been employed to produce a large variety of solid materials such as metals, sulfides, carbides, nitrides and single or complex metal oxides. This review intends to provide a holistic perspective of the different steps involved in the chemistry of SCS of advanced photocatalysts, and pursues several SCS metrics that influence their photocatalytic performances to establish a feasible approach to design advanced photocatalysts. The study highlights the fundamentals of SCS and the importance of various combustion parameters in the characteristics of the fabricated photocatalysts. Consequently, this work deals with the design of a concise framework to link the fine adjustment of SCS parameters for the development of efficient metal oxide photocatalysts for energy and environmental applications.

A review of catalytic hydrogenation of carbon dioxide: From waste to hydrocarbons.

With the rapid development of industrial society and humankind's prosperity, the growing demands of global energy, mainly based on the combustion of hydrocarbon fossil fuels, has become one of the most severe challenges all over the world. It is estimated that fossil fuel consumption continues to grow with an annual increase rate of 1.3%, which has seriously affected the natural environment through the emission of greenhouse gases, most notably carbon dioxide (CO2). Given these recognized environmental concerns, it is imperative to develop clean technologies for converting captured CO2 to high-valued chemicals, one of which is value-added hydrocarbons. In this article, environmental effects due to CO2 emission are discussed and various routes for CO2 hydrogenation to hydrocarbons including light olefins, fuel oils (gasoline and jet fuel), and aromatics are comprehensively elaborated. Our emphasis is on catalyst development. In addition, we present an outlook that summarizes the research challenges and opportunities associated with the hydrogenation of CO2 to hydrocarbon products.

Size-Dependent Microwave Heating and Catalytic Activity of Fine Iron Particles in the Deep Dehydrogenation of Hexadecane.

Knowledge of the electromagnetic microwave radiation-solid matter interaction and ensuing mechanisms at active catalytic sites will enable a deeper understanding of microwave-initiated chemical interactions and processes, and will lead to further optimization of this class of heterogeneous catalysis. Here, we study the fundamental mechanism of the interaction between microwave radiation and solid Fe catalysts and the deep dehydrogenation of a model hydrocarbon, hexadecane. We find that the size-dependent electronic transition of particulate Fe metal from a microwave "reflector" to a microwave "absorber" lies at the heart of efficient metal catalysis in these heterogeneous processes. In this regard, the optimal particle size of a Fe metal catalyst for highly effective microwave-initiated dehydrogenation reactions is approximately 80-120 nm, and the catalytic performance is strongly dependent on the ratio of the mean radius of Fe particles to the microwave skin depth (r/δ) at the operating frequency. Importantly, the particle size of selected Fe catalysts will ultimately affect the basic heating properties of the catalysts and decisively influence their catalytic performance under microwave initiation. In addition, we have found that when two or more materials-present as a mechanical mixture-are simultaneously exposed to microwave irradiation, each constituent material will respond to the microwaves independently. Thus, the interaction between the two materials has been found to have synergistic effects, subsequently contributing to heating and improving the overall catalytic performance.

Sustainable chemical processing of flowing wastewater through microwave energy.

Iron oxide nanostructured catalysts have emerged as potential candidates for efficient energy conversion and electrochemical energy storage devices. However, synthesis and design of nanomaterial plays a key role in its performance and efficiency. Herein, we describe a one-pot solution combustion synthesis (SCS) of α-Fe2O3 with glycine as a fuel, and a subsequent reduction step to produce iron-containing catalysts (i.e., Fe3O4, Fe-Fe3O4, and Fe0). The synthesized iron-based nanoparticles were investigated for methyl orange (MO) degradation through Microwave (MW) energy under continuous flow conditions. Fe-Fe3O4 showed higher MO degradation efficiency than α-Fe2O3, Fe3O4 and Fe0 at low absorbed MW power (i.e. 5-80 W). The enhanced degradation efficiency is associated to the combination of higher availability of electron density and higher heating effect under MW energy. Investigation of dielectric properties showed relative dielectric loss of Fe3O4, Fe-Fe3O4, and Fe0 as 3847, 2010, and 1952, respectively. The calculated average local temperature by the comparative analysis of MW treatment with conventional thermal (CT) treatment showed a marked thermal effect of MW-initiated MO degradation. This work highlights the potential of microwave-driven water depollution under continuous-flow processing conditions and demonstrates the positive impact that earth-abundant Fe catalyst synthesized by green SCS method can have over the treatment of wastewater.

Yolk-Shell Nanocapsule Catalysts as Nanoreactors with Various Shell Structures and Their Diffusion Effect on the CO2 Reforming of Methane.

Well-geometric-confined yolk-shell catalysts can act as nanoreactors that are of benefit for the antisintering of metals and resistance to coke formation in high-temperature reactions such as the CO2 reforming of methane. Notwithstanding the credible advances of core/yolk-shell catalysts, the enlarged shell diffusion effects that occur under high space velocity can deactivate the catalysts and hence pose a hurdle for the potential application of these types of catalysts. Here, we demonstrated the importance of the shell thickness and porosity of small-sized Ni@SiO2 nanoreactor catalysts, which can vary the diffusional paths/rates of the diffusants that directly affect the catalytic activity. The nanoreactor with an ∼4.5 nm shell thickness and rich pores performed the best in tolerating the shell diffusion effects, and importantly, no catalytic deactivation was observed. We further proposed a shell diffusion effect scheme by modifying the Weisz-Prater and blocker model and found that the "gas wall/hard blocker" formed on the openings of the shell pores can cause reversible/irreversible interruption of the shell mass transfer and thus temporarily/permanently deactivate the nanoreactor catalysts. This work highlights the shell diffusion effects, apart from the metal sintering and coke formation, as an important factor that are ascribed to the deactivation of a nanoreactor catalyst.

Catalytic Activity of Various Carbons during the Microwave-Initiated Deep Dehydrogenation of Hexadecane.

Carbon materials have been widely used as microwave susceptors in many chemical processes because they are highly effective at transforming incoming electromagnetic energy for local (hot spot) heating. This property raises the intriguing possibility of using the all-pervasive carbonaceous deposits in operating heterogeneous catalytic processes to augment the catalytic performance of microwave-initiated reactions. Here, the catalytic activities of a range of carbon materials, together with carbon residues produced from a "test" reaction-the dehydrogenation of hexadecane under microwave-initiated heterogeneous catalytic processes, have been investigated. Despite the excellent microwave absorption properties observed among these various carbons, only activated carbons and graphene nanoplatelets were found to be highly effective for the microwave-initiated dehydrogenation of hexadecane. During the dehydrogenation of hexadecane on a Fe/SiC catalyst, active carbon species were formed at the early stage of the reactions but were subsequently transformed into filamentous but catalytically inert carbons that ultimately deactivated the operating catalyst.

Facile in situ reductive synthesis of both nitrogen deficient and protonated g-C3N4 nanosheets for the synergistic enhancement of visible-light H2 evolution.

A new strategy is reported here to synthesize both nitrogen deficient and protonated graphitic carbon nitride (g-C3N4) nanosheets by the conjoint use of NH4Cl as a dynamic gas template together with hypophosphorous acid (H3PO2) as a doping agent. The NH4Cl treatment allows for the scalable production of protonated g-C3N4 nanosheets. With the corresponding co-addition of H3PO2, nitrogen vacancies, accompanied by both additional protons and interstitially-doped phosphorus, are introduced into the g-C3N4 framework, and the electronic bandgap of g-C3N4 nanosheets as well as their optical properties and hydrogen-production performance can be precisely tuned by careful adjustment of the H3PO2 treatment. This conjoint approach thereby results in improved visible-light absorption, enhanced charge-carrier separation and a high H2 evolution rate of 881.7 µmol h-1 achieved over the H3PO2 doped g-C3N4 nanosheets with a corresponding apparent quantum yield (AQY) of 40.4% (at 420 nm). We illustrate that the synergistic H3PO2 doping modifies the layered g-C3N4 materials by introducing nitrogen vacancies as well as protonating them, leading to significant photocatalytic H2 evolution enhancements, while the g-C3N4 materials doped with phosphoric acid (H3PO4) are simply protonated further, revealing the varied doping effects of phosphorus having different (but accessible) valence states.

Transforming carbon dioxide into jet fuel using an organic combustion-synthesized Fe-Mn-K catalyst.

With mounting concerns over climate change, the utilisation or conversion of carbon dioxide into sustainable, synthetic hydrocarbons fuels, most notably for transportation purposes, continues to attract worldwide interest. This is particularly true in the search for sustainable or renewable aviation fuels. These offer considerable potential since, instead of consuming fossil crude oil, the fuels are produced from carbon dioxide using sustainable renewable hydrogen and energy. We report here a synthetic protocol to the fixation of carbon dioxide by converting it directly into aviation jet fuel using novel, inexpensive iron-based catalysts. We prepare the Fe-Mn-K catalyst by the so-called Organic Combustion Method, and the catalyst shows a carbon dioxide conversion through hydrogenation to hydrocarbons in the aviation jet fuel range of 38.2%, with a yield of 17.2%, and a selectivity of 47.8%, and with an attendant low carbon monoxide (5.6%) and methane selectivity (10.4%). The conversion reaction also produces light olefins ethylene, propylene, and butenes, totalling a yield of 8.7%, which are important raw materials for the petrochemical industry and are presently also only obtained from fossil crude oil. As this carbon dioxide is extracted from air, and re-emitted from jet fuels when combusted in flight, the overall effect is a carbon-neutral fuel. This contrasts with jet fuels produced from hydrocarbon fossil sources where the combustion process unlocks the fossil carbon and places it into the atmosphere, in longevity, as aerial carbon - carbon dioxide.

Water/oil microemulsion for the preparation of robust La-hexaaluminates for methane catalytic combustion.

Robust and highly effective Fe-substituted and non-substituted La-Hexaaluminate methane combustion catalysts have been prepared via coprecipitation in "water-pools" of Water/Oil microemulsions with dual nonionic surfactants, followed by ethanol supercritical drying and post-annealing.

Inhibitory effects of polysaccharide from Diaphragma juglandis fructus on α-amylase and α-d-glucosidase activity, streptozotocin-induced hyperglycemia model, advanced glycation end-products formation, and H2O2-induced oxidative damage.

In present study, the in vitro and in vivo hemolysis inhibitory, protective effect against reactive oxygen species (ROS) induced oxidative damage in L02 cells, hypoglycemic, and antiglycation activities of DJP-2, a pure polysaccharide fraction from Diaphragma juglandis fructus, were investigated. Results demonstrated that DJP-2 showed remarkable hemolysis inhibitory activity. Pretreatment with DJP-2 markedly weakened the oxidative damage induced by H2O2 in hepatic L02 cells via strengthening the cell viability. DJP-2 also showed clear in vivo and in vitro hypoglycemic activities. Besides, DJP-2 with the concentration of 3 mg/mL exerted more significant antiglycation activities than aminoguanidine during 30 days of incubation. The results obtained in this study would be beneficial for the application of DJP-2 to treat various diseases related to oxidative stress and AGEs. The elucidation of the potential bioactivities of DJP-2 will facilitate its further study and application in the functional food industry and pharmaceuticals industry.

Synergistic Effect of Oxygen Vacancies and Ni Species on Tuning Selectivity of Ni/ZrO2 Catalyst for Hydrogenation of Maleic Anhydride into Succinic Anhydride and γ-Butyrolacetone.

ZrO2 nanoparticles, ZrO2 (P) and ZrO2 (H), with different tetragonal phase contents, were prepared. ZrO2 (P) possessed higher tetragonal phase content than ZrO2 (H). Ni/ZrO2 catalysts (10% (w/w)), using ZrO2 (P) and ZrO2 (H) as supports, were prepared using an impregnation method, and were characterized using XRD, Raman, H2-TPR, XPS, and H2-TPD techniques. Their catalytic performance in maleic anhydride hydrogenation was tested. The Ni/ZrO2 (P) catalyst exhibited stronger metal-support interactions than the Ni/ZrO2 (H) catalyst because of its higher number of oxygen vacancies and the low-coordinated oxygen ions on its surface. Consequently, smaller Ni crystallites and a higher C=C hydrogenation activity for maleic anhydride to succinic anhydride were obtained over a Ni/ZrO2 (P) catalyst. However, the C=O hydrogenation activity of Ni/ZrO2 (P) catalyst was much lower than that of the Ni/ZrO2 (H) catalyst. A 43.5% yield of γ-butyrolacetone was obtained over the Ni/ZrO2 (H) catalyst at 210 °C and 5 MPa of H2 pressure, while the yield of γ-butyrolactone was only 2.8% over the Ni/ZrO2 (P) catalyst under the same reaction conditions. In situ FT-IR characterization demonstrated that the high C=O hydrogenation activity for the Ni/ZrO2 (H) catalyst could be attributed to the surface synergy between active metallic nickel species and relatively electron-deficient oxygen vacancies.

Solvothermal synthesis of N-doped TiO2 nanotubes for visible-light-responsive photocatalysis.

Visible-light-responsive tubular N-doped TiO2 nanocrystallites were synthesized via an environment-conscious solvothermal treatment of protonated titanate nanotubes in an NH4Cl/ethanol/water solution.

The role of photoinduced defects in TiO2 and its effects on hydrogen evolution from aqueous methanol solution.

The hydrogen evolution from aqueous methanol solutions was found to follow two stages of zero order kinetics during photoreactions using TiO 2 as the photocatalyst. Maximal hydrogen evolution was found at the 10% (v/v) methanol solution. X-ray photoelectron spectroscopy (XPS) shows that Ti(1566) defects are formed on the surface of TiO 2 and X-ray powder diffraction (XRD) indicates that Ti(1566) defects are also formed in the bulk after photoreaction. Formation of defects is also shown by broadening of Bragg peaks and blue shifts and peak broadening in Raman spectroscopy. The defect disorder results in the increase of hydrogen evolution. UV-vis diffuse reflection spectra confirm that new absorptions in the visible light region are related to the defect content. At high methanol concentration, XPS implies that the active sites of the surface are blocked by hydroxyl groups, which results in the decrease of hydrogen evolution. TEM images showed that the photoreaction occurred on the surface of the photocatalyst as the surface of the TiO 2 became rough after the photoreaction.