Synthesis and crystal structure of the low-temperature modification of Li<Subscript>12</Subscript>Zn<Subscript>4</Subscript>(P<Subscript>2</Subscript>O<Subscript>7</Subscript>)<Subscript>5</Subscript>

The crystal structure of a low-temperature modification of the Li₁₂Zn₄(P₂O₇)₅ compound has been determined by full-profile analysis from the X-ray powder diffraction data. The compound crystallizes in the monoclinic crystal system (a = 5.130(1) Å, b = 13.454(1) Å, c = 8.205(1) Å, β = 90.36(1)°, space group P2₁/n, Z = 4) and has a framework structure in which the zinc and lithium atoms statistically occupy equivalent positions.     

Identification of Crepenynic Acid in the Seed Oil of <Emphasis Type="Italic">Atractylodes lancea</Emphasis> and <Emphasis Type="Italic">A. macrocephala</Emphasis>

Atractylodes rhizome is widely used in traditional Chinese herbal medicine. Although the chemical composition of the root has been studied in detail, the oil content and fatty acid composition of the seeds of Atractylodes species have not been reported. Fatty acyl composition of seeds from Atractylodes lancea and A. macrocephala was determined by gas chromatography and mass spectrometry of fatty acid methyl esters and 3-pyridylcarbinol esters. The predominant fatty acid in the seeds of both species was linolenic acid, but the unusual acetylenic fatty acid, crepenynic acid (cis-9-octadecen-12-ynoic acid), was also observed at levels of 18% in A. lancea and 13–15% in A. macrocephala. Fatty acid content was 24% for the samples of A. lancea and 16–17% for samples from A. macrocephala. sn-1,3 regioselective lipase digestion of seed lipids revealed that crepenynic acid was absent from the sn-2 position of the seed triacylglycerol. Crepenynic acid was also found in the seed oil of Jurinea mollis at 24% and was not present in the sn-2 position of the TAG. A contrasting distribution of crepenynic acid was found in the oil of Crepis rubra, suggesting differences in crepenynic acid synthesis or TAG assembly between these species.     

Density and microhardness of glasses in the SrO-B<Subscript>2</Subscript>O<Subscript>3</Subscript>-SiO<Subscript>2</Subscript> system

The density d at a temperature of 25°C is measured by the hydrostatic weighing method, the Vickers microhardness H _V is determined, and the fluctuation free volume fraction f _g is calculated for glasses in the SrO-B₂O₃-SiO₂ system with a constant strontium oxide content in the range from 35 to 45 mol %. It is demonstrated that the quantities H _V and f _g decrease and the density d increases with an increase in the SrO content.     

Crystal structure of Pb<Subscript>6</Subscript>O[(Si<Subscript>6</Subscript>Al<Subscript>2</Subscript>)O<Subscript>20</Subscript>]

The crystal structure of Pb₆O[(Si₆Al₂)O₂₀)] is investigated using X-ray diffraction. The compound has tetragonal symmetry, space group I4/mmm, a = 11.7162(10) Å, c = 8.0435(12) Å, and V = 1104.13(2) ų. The structure is refined to R ₁ = 0.036 for 562 unique reflections with [F ₀] ≥ 4σF. The structure contains two symmetrically independent positions of the Pb²⁺ cations coordinated by five O atoms (Pb²⁺-O^2? = 2.34–2.68 Å). The TO₄ tetrahedra (T = Si, Al) form tubular [(Si₆Al₂)O₂₀] chains extended along the c axis. The O₄ oxygen atom is not bonded to the Si and Al atoms and is octahedrally coordinated by six Pb atoms with the formation of an oxo-centered OPb₆ octahedron. The assumption is made that, in some of lead silicate and aluminosilicate glasses, a number of oxygen atoms are located outside the tetrahedral structure and represent segregation centers of the Pb²⁺ cations due to the formation of oxo-centered complexes.     

Crystal structure and thermal expansion of ammonium pentaborate NH<Subscript>4</Subscript>B<Subscript>5</Subscript>O<Subscript>8</Subscript>

Anhydrous ammonium pentaborate NH₄B₅O₈ has been synthesized by thermal dehydration of larderellite NH₄[B₅O₇(OH)₂] · H₂O at a temperature of 290°C for 7 h. The crystal structure has been determined from the X-ray powder diffraction data: a = 7.58667(5) Å, b = 12.00354(8) Å, c = 14.71199(8) Å, R _p = 6.23, R _wp = 7.98, R _B = 12.7, R _F = 8.95, and β-KB₅O₈ structure type. The double interpenetrating framework is formed by pentaborate groups, each consisting of a boron-oxygen tetrahedron and four triangles, in which all oxygen atoms are bridging. The thermal behavior of the NH₄B₅O₈ compound has been investigated using thermal X-ray diffraction. As for other pentaborates of this type, the thermal expansion of the NH₄B₅O₈ compound is anisotropic and reaches a maximum along the a axis. The thermal expansion coefficients are as follows: α _a = 39 × 10^?6, α _b = 6 × 10^?6, α _c = 20 × 10^?6, and α _V = 65 × 10^?6 °C^?1.     

CO and CO<Subscript>2</Subscript> methanation over Ni catalysts supported on alumina with different crystalline phases

The effect of alumina crystalline phases on CO and CO₂ methanation was investigated using alumina-supported Ni catalysts. Various crystalline phases, such as α-Al₂O₃, θ-Al₂O₃, δ-Al₂O₃, η-Al₂O₃, γ-Al₂O₃, and κ-Al₂O₃, were utilized to prepare alumina-supported Ni catalysts via wet impregnation. N₂ physisorption, H₂ chemisorption, temperature-programmed reduction with H₂, CO₂ chemisorption, temperature-programmed desorption of CO₂, and X-ray diffraction were employed to characterize the catalysts. The Ni/θ-Al₂O₃ catalyst showed the highest activity during both CO and CO₂ methanation at low temperatures. CO methanation catalytic activity appeared to be related to the number of Ni surface-active sites, as determined by H₂-chemisorption. During CO₂ methanation, Ni dispersion and the CO₂ adsorption site were found to influence catalytic activity. Selective CO methanation in the presence of excess CO₂ was performed over Ni/γ-Al₂O₃ and Ni/δ-Al₂O₃; these substrates proved more active for CO methanation than for CO₂ methanation.     

Synthesis of Structured Lipids Containing Pinolenic Acid at the <Emphasis Type="Italic">sn</Emphasis>-2 Position via Lipase-Catalyzed Acidolysis

Lipase-catalyzed acidolysis of a modified pine nut oil (MPNO)—the pine nut oil was obtained from Pinus koraiensis Siebold &; Zucch.—with capric acid was studied in a continuous packed bed reactor (PBR) using Lipozyme RM IM from Rhizomucor miehei as a biocatalyst. The MPNO containing pinolenic acid (PLA) at the sn-2 position of the triacylglycerol (TAG) backbone was prepared by lipase-catalyzed redistribution of pine nut oil using Novozym 435 from Candida antarctica. The effects of the water content in the reaction mixture and the molar ratio of substrates on the extent of the acidolysis reaction as a function of residence time in a PBR were investigated. The water content of the reaction mixture significantly influenced both the rate of acidolysis and the degree of acyl migration, but the molar ratio of substrates affected only the rate of acidolysis. The optimum water content and molar ratio for synthesis of the structured lipid containing PLA at the sn-2 position and capric acid at the sn-1,3 positions of the TAG backbone were 0.04%, and 1:5 (MPNO to capric acid), respectively.     

Raman spectra and surface structure of CaO-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript>-SiO<Subscript>2</Subscript> glass leached in potassium hydroxide solutions

It is difficult to research on the surface structure of amorphous phase in fly ash during leaching reaction due to crystalline phase and complex structure. In the present work, in order to reveal the effects of leaching reaction on the surface structure of amorphous phase in fly ash, the modelling CaO-Fe₂O₃-Al₂O₃-SiO₂ glass was prepared by the traditional melting methods. The leaching reaction of CaO-Fe₂O₃-Al₂O₃-SiO₂ glass with 7.5 M KOH was investigated by spectroscopy, spectrophotometer and wet chemical method. The results show that the content of Q ¹, Q ², Q ³ and Q ⁴ of glass without corrosion was 4.21, 9.51, 23.03 and 52.55%, respectively, which shows that the network polymerization of glass is compact. The leaching reaction of glass can be described by the following equation: dS/dt = k/(r + S ₀). Leaching in KOH for various times induces the content of Q ⁴ and Q ¹ to be decreased, and Q ² and Q ³ increased, resulted in the depolymerization of network and the surface glass dissolved in alkaline solution to form a gel phase. In stage one of leaching reaction, the rate of iron ion leached from glass surface was slow, which resulted in the small slope of straight-line relationship of leaching curve. In the following stage, the leaching rate of iron ion increased with the prolongation of time.     

Oxychlorination of methane over FeO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>/CeO<Subscript>2</Subscript> catalysts

Methane activation through oxychlorination is in the spotlight due to the relatively mild reaction conditions at atmospheric pressure and in the temperature range of 450–550 °C. Although CO₂ is known to exhibit good activity for methane oxychlorination, significant amounts of by-products such as CO₂, CO and carbon deposits are produced during the reaction over CO₂. We investigated the effect of iron in FeO_x/CO₂ catalysts on methane oxychlorination. FeO_x/CO₂ with 3 wt% iron shows the maximum yield at 510 °C with 23% conversion of methane and 65% selectivity of chloromethane. XRD and H₂ TPR results indicate that iron-cerium solid solution was formed, resulting in the production of more easily reduced cerium oxide and the suppression of catalysts sintering during the reaction. Furthermore, the selectivity of by-products decreased more significantly over FeO_x/CO₂ than cerium oxide, which can be attributed to the facilitation of HCl oxidation arising from the enhanced reducibility of the former sample.     

Adsorption characteristics analysis of CO<Subscript>2</Subscript> and N<Subscript>2</Subscript> in 13X zeolites by molecular simulation and N<Subscript>2</Subscript> adsorption experiment

The adsorption characteristics of CO₂ and N₂ in 13X zeolites have been studied by the molecular simulation and N₂ adsorption experiment. It is found that the simulation results by Dreiding force fields are in an agreement with the published data. The influence of the σ and ε parameters of O_Z and Na⁺ on the adsorption performance is discussed. Then the optimized force field parameters are obtained. Specific surface area (S _B ) is calculated by simulation and experiment. Its relative error is just only 4.3 %. Therefore, it is feasible that S _B of 13X zeolites is obtained by the simulation methods. Finally, the impacts of pressure and temperature on adsorption characteristics are investigated. At low pressure, CO₂ adsorption in 13X zeolites belongs to the surface adsorption. As the pressure increase, the partial multilayer adsorption appears along with the surface adsorption. N₂ adsorption in 13X zeolites is different from that of CO₂. At low temperature of 77 K, two primary peaks are caused by the surface adsorption and multilayer adsorption respectively regardless of pressure variation. When the temperature is 273 K, the energy distribution curve appears undulate at low pressures. Then it becomes stable with the pressure increase. The surface adsorption plays an important role at the relative high pressures. The results will help to provide the theory guide for the optimization of force field parameters of adsorbents, and it is very important significance to understand the adsorption performance of zeolites.     

Glucose Uptake and Triacylglycerol Synthesis Are Increased in Barth Syndrome Lymphoblasts

Barth syndrome (BTHS) is an X-linked genetic disease resulting in loss of cardiolipin (Ptd₂Gro). Patients may be predisposed to hypoglycemia and exhibit increases in whole-body glucose disposal rates and a higher fat mass percentage. We examined the reasons for this in BTHS lymphoblasts. BTHS lymphoblasts exhibited a 60% increase (p < 0.004) in 2-[1,2-³H(N)]deoxy-d-glucose uptake, a 40% increase (p < 0.01) in glucose transporter-3 protein expression, an increase in phosphorylated-adenosine monophosphate kinase (AMPK) and a 58% increase (p < 0.001) in the phosphorylated-AMPK/AMPK ratio compared to controls. In addition, BTHS lymphoblasts exhibited a 90% (p < 0.001) increase in d-[U-¹⁴C]glucose incorporated into 1,2,3-triacyl-sn-glycerol (TAG) and a 29% increase (p < 0.025) in 1,2-diacyl-sn-glycerol acyltransferase-2 activity compared to controls. Thus, BTHS lymphoblasts exhibit increased glucose transport and increased glucose utilization for TAG synthesis. These results may, in part, explain why BTHS patients exhibit an increase in whole-body glucose disposal rates, may be predisposed to hypoglycemia and exhibit a higher fat mass percentage.     

Synthesis and crystal structure of a new oxohalide CdPb<Subscript>2</Subscript>O<Subscript>2</Subscript>Cl<Subscript>2</Subscript>

A new compound, CdPb₂O₂Cl₂, is synthesized by the method of solid-phase reactions. The compound has monoclinic symmetry, space group C2/m, a = 12.392(8) Å, b = 3.8040(14) Å, c = 7.658(5) Å, β = 122.64(5)°, and V = 304.0(3) ų. The structure contains one symmetrically independent position of the Pb²⁺ cation coordinated by three O^2? anions (Pb²⁺-O^2? = 2.29–2.34 Å) and five Cl^? anions (Pb²⁺-Cl^? = 3.35–3.57 Å). The Cd²⁺ cation has a symmetric coordination with the formation of two bonds Cd-O = 2.15 Å and four bonds Cd-Cl = 2.73 Å. The oxygen atom is tetrahedrally coordinated by three Pb²⁺ cations and one Cd²⁺ cation, which leads to the formation of oxo-centered heterometallic OPb₃Cd tetrahedra. The tetrahedra are linked together into chains through common Pb atoms and into layered complexes due to sharing of the equatorial Cd atoms. The chlorine atoms are located above the cavities of the oxo-centered layer.     

Stability of polymer structures based on fullerene C<Subscript>60</Subscript> under their oxidation with oxygen

A comparative study of the oxidative destruction of the monomer face-centered cubic (FCC) lattice and various polymer [dimeric (D), orthorhombic (O), tetragonal (T), and rhombohedral (R)] phases of C₆₀ in an atmosphere of oxygen has been performed in the temperature range of 100–500°C with the use of a flow microunit connected to a gas chromatograph. From direct measurements of the content of CO₂ in the gaseous products of destruction, the temperature dependences of oxidation rates are measured for the materials under study. It has been established that, with respect to stability against oxidative destruction, different forms of C₆₀ may be arranged as follows: the monomer FCC phase of C₆₀ > D > O > T > R. The reasons behind this tendency are discussed.     

Solution-Combustion Synthesis of LiNi<Subscript>1/3</Subscript>Co<Subscript>1/3</Subscript>Mn<Subscript>1/3</Subscript>O<Subscript>2</Subscript> as a Cathode Material for Lithium-Ion Batteries

A cathode material for lithium-ion batteries–LiNi_1/3Co_1/3Mn_1/3O₂–was prepared by solution combustion synthesis and characterized by XRD, SEM, and galvanostatic charge/discharge cycling. The sample calcined at 950°C for 10 h showed best charge/discharge performance. An initial discharge capacity (C) of 150.5 mA h g^–1 retained 95.7% of its value after 75 charge/discharge cycles at I_c = 14 mA g^–1 (0.2C rate), I_d = 70 mA g^–1 (0.5C rate).     

SHS of Y<Subscript>2</Subscript>Ti<Subscript>2</Subscript>O<Subscript>7</Subscript>-based mineral-like ceramics: Influence of green density

Explored was the influence of compacting pressure (P) and green density (ρ) on the properties of Zr-doped mineral-like pyrochlore ceramics Y₂(Ti_{1 – x} Zr _x )₂O₇ (x ≤ 0.3) prepared by SHS method. The optimal ρ values that provide minimal porosity and maximal mechanical strength of synthesized ceramics were found. An increase in ρ was found to decrease combustion temperature and increase pyrochlore lattice parameter a. Green density was also found to affect phase composition of the SHS-produced ceramics under study.     

Transport properties of solid electrolytes based on <Emphasis Type="Italic">Me</Emphasis>Sm<Subscript>2</Subscript>S<Subscript>4</Subscript>

The solid-solution regions in the MeSm₂S₄-MeS and MeSm₂S₄-Sm₂S₃ (Me = Ca, Ba) systems are revealed. The average ion, cation, and anion transport number of the synthesized solid electrolytes xSm₂S₃[Ca(Ba)S] · (100 ? x)Ca(Ba)Sm₂S₄ (x = 1?10 mol %) are determined by the electromotive force (emf) method with the use of concentration cells with and without transfer. In the phases under investigation, the ion transfer in the temperature range 673–723 K is provided by sulfide ions (\(t_{S^2 } \) = 1.00±0.02). The diffusion coefficients of S^2? ions in the solid electrolytes are determined by potentiostatic chronoamperometry. A vacancy mechanism of defect formation is proposed. It is demonstrated that the transport characteristics of the solid electrolytes based on the CaSm₂S₄ compound are worse than those of the solid electrolytes based on the BaSm₂S₄ compound.     

Production of MLM-Type Structured Lipids Catalyzed by Immobilized Heterologous <Emphasis Type="Italic">Rhizopus oryzae</Emphasis> Lipase

This work aims to produce triacylglycerols (TAG) containing a medium-chain fatty acid (M) at positions sn-1,3 and a long-chain fatty acid (L) at sn-2 position, i.e. TAG of MLM type, by acidolysis of virgin olive oil with caprylic (C8:0) or capric (C10:0) acids, catalyzed by 1,3-selective Rhizopus oryzae heterologous lipase (rROL) immobilized in Eupergit^® C and modified sepiolite. This lipase was produced by the methylotrophic yeast Pichia pastoris. Reactions were performed at 25 and 40 °C, for 24 h, either in solvent-free or in n-hexane media, at a molar ratio 1:2 (olive oil:free fatty acid). Higher incorporations of C8:0 (21.6 mol%) and C10:0 (34.8 mol%) into the TAG were attained in solvent-free media, at 40 °C, when rROL immobilized in Eupergit^® C was used. In organic media, at 40 °C, only 15.9 and 14.1 mol%, incorporation of C8:0 or C10:0 were, respectively observed. Lower incorporations were attained for both acids (3.4–7.0 mol%) when native ROL (nROL) in both supports and rROL in modified sepiolite were used. rROL in Eupergit^® C maintained its activity during the first four or three 23-h batches, respectively when C8:0 (half-life time, t _1/2 = 159 h) or C10:0 (t _1/2 = 136 h) were used, decreasing thereafter following a time delay model.     

Ratios of Regioisomers of Minor Acylglycerols Less Polar than Triricinolein in Castor Oil Estimated by Mass Spectrometry

We have recently reported the identification of forty new minor molecular species of acylglycerols containing hydroxy fatty acids less polar than triricinolein by electrospray ionization mass spectrometry of the lithium adducts. The ratios of regioisomers of triacylglycerols (ABC and AAB types) and tetraacylglycerols (AAAB type) identified were estimated by the relative abundances of the fragment ions from the neutral losses of fatty acids as α,β-unsaturated fatty acids at the sn-2 position. The order of the contents of regioisomers of triacylglycerols with the fatty acids at the sn-2 position are: nonhydroxy fatty acids > monohydroxy fatty acids > dihydroxy fatty acids > trihydroxy fatty acids. For tetraacylglycerols (AAAB type) such as ricinoleoylricinoleoyl–ricinoleoyl–oleoyl–glycerol (RRRO), ricinoleoylricinoleoyl chain was predominately at the sn-2 position, while ricinoleate was not detected at the sn-2 position.     

Synthesis of Titanates with a Ramsdellite-Type Tunnel Structure Crystallizing in the Li<Subscript>2</Subscript>O-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>-TiO<Subscript>2</Subscript> System in Different Gaseous Media

The ramsdellite-type phases crystallizing in the Li₂O-Fe₂O₃-TiO₂ system in the course of synthesis in gaseous media at different oxygen partial pressures are studied. Solid solutions based on the ramsdellite structure with the composition Li₂Ti_3?xFe _x O_{7 ? δ} (0 ≤ x ≤ 0.7) are prepared in an oxidizing medium (P_O2 = 1 atm) for the first time. Analysis of the results obtained by electron paramagnetic resonance and Mossbauer spectroscopy revealed that, in these solid solutions, all iron ions are in the oxidation state Fe⁺³.     

Crystal structure of new compound (Rb,K)<Subscript>2</Subscript>Cu<Subscript>3</Subscript>(P<Subscript>2</Subscript>O<Subscript>7</Subscript>)<Subscript>2</Subscript>

A new compound of (Rb,K)₂Cu₃(P₂O₇)₂ is obtained by high-temperature reactions from a mixture of RbNO₃, KNO₃, Cu(NO₃)₂, and (NH₄)₄P₂O₇. The crystal structure was solved by direct methods and refined to R ₁ = 0.056 for 5022 independent reflections. The compound belongs to a rhombic crystal system, P2₁2₁2₁, Z = 8, a = 9.9410(7) Å, b = 13.4754(6) Å, c = 18.6353 (3) Å, and R = 0.056. The basis of the structure is a complex copper-phosphate skeleton of the composition of [Cu₃(P₂O₇)₂]^2–, which can be regarded as consisting of two types of heteropolyhedral layers parallel to the (001) plane. The layers are alternated with each other, forming a frame, in the cavities of which the positions of alkali cations are located, statistically populated with K⁺ and Rb⁺ ions. Based on the refined populations of the positions of alkali cations, an exact chemical formula of the compound can be written as Rb_1.28K_0.72Cu₃(P₂O₇)₂. The compound is the most complex among those known to this day of the composition of A₂ ^IB₃ ^II(P₂O₇)₂ (A = Li, Na, K, Rb, or Cs; B = Ni, Cu, or Zn).