Theoretical study of H⋯P and X⋯P interactions of methylphosphines with HSX molecules

Ab initio calculations were used to analyze the interactions between thiohypohalous acids (HSX; X = F, Cl, Br, I) and methylphosphine derivatives (PH _n Me_3?n , n = 0–3) at the MP2/aug-cc-pVDZ level of theory. Interaction of HSX with PH _n Me_3?n leads to both hydrogen bond (HSX–PH _n Me_3?n –HB) as well as halogen bond (HSX–PH _n Me_3?n –XB) complexes. Stabilities of both HB and XB complexes increase with basicity of the phosphines. However, HB complexes of a phosphine molecule with different HSX have the same order of stabilities, but XB complexes of heavier thiohypohalous acids are more stable. Electron densities of complexes were characterized with the atoms in molecules methodology. The charge transfer within dimers was analyzed by means of natural bond orbitals.     

Theoretical study on the small carbon nano-ladders

1,3-Butadiyne, 1,3,5-hexatriyne, 1,3,5,7-octatetrayne, and 1,3,5,7,9-decapentayne are small oligomeric forms of acetylene. These oligomers participate in cyclization reactions to form ladder-like structures. Enthalpies, ?H, and Gibbs free energies, ?G, of the cyclization reactions were calculated employing MP2 and B3LYP methods. The calculated ?H and ?G were positive, and their variation versus carbon atoms number, n, was fitted in linear functions as ?H(n) = a+bn. The calculations were performed on the structures with carbon numbers up to 20. Also, consecutive cyclization reactions between acetylene molecules were studied. During these consecutive reactions, two different structures, zigzag-ladder-like and cyclic molecules with tetragonal rings, were produced. Among the cyclic structures, the hexagonal form was the most stable structure. The calculated ?H and ?G of formation of zigzag-ladder-like molecules were excellently fitted in linear functions. The obtained functions for ?H and ?G calculated by MP2 method are ?H(n) = 139.67?126.44n and ?G(n) = 80.987?75.684n, respectively.     

Enhancement of Biogas Production by Co-digestion of Potato Pulp with Cow Manure in a CSTR System

Anaerobic digestion (AD) process is a well-established method to generate energy from the organic wastes both from the environmental and economical perspectives. The purpose of present study is to evaluate energy production from potato wastes by incorporating cow manure into the process. Firstly, a laboratory pilot of one-stage biogas production was designed and built according to continuously stirred tank reactor (CSTR) system. The setup was able to automatically control the environmental conditions of the process including temperature, duration, and rate of stirring. AD experiment was exclusively performed on co-digestion of potato peel (PP) and cow manure (CM) in three levels of mixing ratio including 20:80, 50:50, 80:20 (PP:CM), and 0:100 as control treatment based on the volatile solid (VS) weight without adding initial inoculums. After hydraulic retention time (HRT) of 50 days on average 193, 256, 348, and 149 norm liter (L_N) (kg VS)^?1, methane was produced for different mixing ratios, respectively. Statistical analysis shows that these gas productions are significantly different. The average energy was determined based on the produced methane which was about 2.8 kWh (kg VS)^?1, implying a significant energy production potential. The average chemical oxygen demand (COD) removal of treatments was about 61 %, showing that it can be leached significantly with high organic matter by the employed pilot. The energy efficiency of 92 % of the process also showed the optimum control of the process by the pilot.     

Optimization of fundamental parameters in routine production of 90Y-hydroxyapatite for radiosynovectomy

Hydroxyapatite was applied as a carrier adsorbing ⁹⁰Y³⁺ ions for ⁹⁰Y-HA colloid production. The radiopharmaceutical colloid was prepared by adding an acidic solution of ⁹⁰YCl₃ to HA suspension in saline solution. Effective parameters on labeling of ⁹⁰Y-HA were evaluated. Adsorption and cation-exchange properties were studied using inductively coupled plasma elemental analysis and N₂ adsorption–desorption isotherm method. Radionuclidic purity was over 99.9 %. Labeling yield and radiochemical purity were >99 %. Radiochemical purity was evaluated also in human albumin for 7 days at 37 °C. Biodistribution studies have shown complete retention of injected radioactivity at the administration site up to 72 h.     

绿色可磁性分离二氧化硅包裹镍铁尖晶石负载硫酸氢铁纳米粒子催化剂用于合成1,8-二氧十氢吖啶合成Amir Khojastehnezhad,Mohammad Rahimizadeh,简

A new magnetically separable catalyst consisting of ferric hydrogen sulfate supported on silica-coated nickel ferrite nanoparticles was prepared. The synthesized catalyst was characterized using vibrating sample magnetometry, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy. This new magnetic catalyst was shown to be an efficient heterogeneous catalyst for the synthesis of 1,8-dioxodecahydroacridines under solvent-free conditions. The catalyst is readily recovered by simple magnetic decantation and can be recycled several times with no significant loss of catalytic activity.     

基于纳米结构的电化学传感器同时测定溶液中异丙肾上腺素、尿酸和叶酸的浓度(英文)

A carbon paste electrode modified with 2‐((7‐(2,5-dihydrobenzylideneamino)heptylimino)methyl) benzene‐1,4‐diol(DHB) and carbon nanotubes were used to simultaneously determine the concen-trations of isoproterenol(IP), uric acid(UA), and folic acid(FA) in solution. First, cyclic voltammetry was used to investigate the redox properties of the modified electrode at various scan rates. Next, the mediated oxidation of IP at the modified electrode is described. At the optimum pH of 7.0, the oxidation of IP occurs at a potential about 90 mV less than that of an unmodified carbon paste elec-trode. Based on the results of differential pulse voltammetry(DPV), the oxidation of IP showed a dynamic range between 10 and 6000 μmol/L, and a detection limit of 1.24 μmol/L. Finally, DPV was used to simultaneously determine the concentrations of IP, UA, and FA in solution at the modified electrode.     

Thermal performance of poly(ethylene disulfide)/expanded graphite nanocomposites

In this study, the influences of expanded graphite oxide (EG) nanosheets presence with and without surfactant on structural and thermal performance of poly(ethylene disulfide) (PEDS)-based nanocomposites are investigated. Sodium dodecylbenzenesulfonate (SDBS) is used as a surfactant for the preparation of modified-EG nanosheets. The structural, morphological, and thermal properties of prepared nanocomposites are studied using X-ray diffraction (XRD), scanning electron microscopy, and differential scanning calorimetry techniques, respectively. XRD patterns of nanocomposites reveal that a high degree of expanded graphite nanosheets dispersion is achieved with and without surface modification using in situ polymerization method. Moreover, the presence of immobilized polysulfide chains near the interface region of nanosheets is suggested as a possible reason for the observed increase in the number of semi-crystalline organic fractions in the structure of PEDS via EG nanosheets incorporation. In addition, the morphology of SDBS-modified-EG loaded nanocomposite shows a smoother fracture surface than unmodified-nanosheets reinforced nanocomposite. Therefore, more interactions between nanosheets and polysulfide chains are expected in the structure of unmodified-EG reinforced nanocomposite. Moreover, thermal resistance and degradation kinetics of prepared nanocomposites are studied using thermogravimetric analysis results and degradation activation energy calculations, respectively. The required activation energy for the degradation process of SDBS-EG loaded nanocomposite is about 140 kJ mol^?1 lower than the required degradation activation energy of unmodified-nanosheets reinforced nanocomposite.     

A Simple Approach to Assess the Performance of Non-ideal Aluminum/Ammonium Perchlorate Composite Explosives as Compared to the Best Available Methods

Composite explosives containing aluminum/ammonium perchlorate (Al/AP) are widely used for blasting cut of old warship, blasting droll and decoupled charge of blast underwater. The available complex computer codes and empirical methods cannot usually provide a reliable estimation of detonation velocities of explosives containing Al/AP. This work introduces a reliable method for the desk calculation of detonation velocity. The percent of the reacted Al with detonation products and decomposition of AP, as well as composition of the detonation products, are specified according to the distribution of oxygen atoms between Al, C(s), CO(g) and H₂(g). The values of the mean absolute percentage error (MAPE) of the new model are lower than one of the best available methods for CHNO explosives (260 experimental data) and CHNOFCl explosives (50 measured data). For composite explosives, CHNOFClAl and CHNOFClAlAP, the MAPE value of the new model is 3.50, corresponding to 55 experimental data, which is much smaller than the MAPE values of the BKW computer code (8.37) and the comparative empirical model (14.20).     

An Efficient Method for Chemoselective Reduction of Nitro Compounds Using Bimetallic Fe‐Ni NPs/H3PW12O40.×H2O System

The selective reduction of nitro compounds by treatment with bimetallic Fe‐Ni nanoparticles (NPs) and tungestophosphoric acid hydrate (H₃PW₁₂O₄₀.×H₂O) in H₂O is reported. The method has been applied to a broad range of nitro compounds with different sensitive functionalities, including halides, carbonyl, hydroxyl, aldehyde, methyl, acetyl, nitrile, and ester substituents with excellent yields. The reaction yielded single product in all cases with very high yield. The simple experimental procedure and easy purification make the protocol advantageous.     

Efficient and Eco‐friendly Syntheses of 1,5‐Benzothiazepines and 1,5‐Benzodiazepines Catalyzed by [Hmim][NO3] under Mild Conditions

This article presents a synthetic method and reaction mechanism of the 1,5‐benzothiazepines and 1,5‐benzodiazepines derivatives. In this research, 36 thiazepines and diazepines (mostly new) with a new method have been prepared and their structures have been characterized by spectroscopic methods. Crystal structures of a new thiazepine and diazepine (seven‐membered rings) have also been determined and compared with thiazine (six‐membered ring). In this method, N‐methylimidazolium nitrate [Hmim][NO₃] has been used as a catalyst that acts as an environmental friendly system.