Thermophysical Properties of High-Temperature Reacting Mixtures of Carbon and Water in the Range 400–30,000 K and 0.1–10 atm. Part 1: Equilibrium Composition and Thermodynamic Properties

This paper is devoted to the calculation of the chemical equilibrium composition and thermodynamic properties of reacting mixtures of carbon and water at high temperature. Equilibrium particle concentrations and thermodynamic properties including mass density, molar weight, entropy, enthalpy and specific heat at constant pressure, sonic velocity, and heat capacity ratio are determined by the method of Gibbs free energy minimization, using species data from standard thermodynamic tables. The calculations, which assume local thermodynamic equilibrium, are performed in the temperature range from 400 to 30,000 K for pressures of 0.10, 1.0, 3.0, 5.0 and 10.0 atm. The properties of the reacting mixture are affected by the possible occurrence of solid carbon formation at low temperature, and therefore attention is paid to the influence of the carbon phase transition by comparing the results obtained with and without considering solid carbon formation. The results presented here clarify some basic chemical process and are reliable reference data for use in the simulation of plasmas in reacting carbon and water mixtures together with the need of transport coefficients computation.     

Silver(I) mediated folding of a molecular basket

We have investigated Ag(I) mediated folding of a tridentate compound, containing three pyridine flaps tethered to a semirigid scaffold, into a molecular basket, using both experimental and theoretical methods. The basket formation has been shown to be highly favorable in organic media (Delta G degrees = -7.2 kcal/mol), with the assembly process allowing for another ligand to bind preferentially on the outer side.     

Microheterogeneous structure of 1-octanol in neat and water-saturated state

The conformational and dynamic properties of 1-octanol in neat and in water-saturated states have been investigated by 1H NMR. It has been proved that neat 1-octanol is microheterogeneous in nature comprising regions enriched in either hydrocarbons or hydroxyl groups. A reversed micelle-like cluster model was proposed, where the octanol cluster has an inner polar core of hydrogen-bonded octanol hydroxyls and an outer shell of nonpolar alkyl chains radiating outside. It was also observed that the cluster structure of octanol experiences minor changes with the presence of water. In water-saturated octanol, water molecules associate via hydrogen bonding and reside in the innermost center of the polar region with restricted motion, whereas the octanol cluster structure is modified by loosening the compact structure. Moreover, the preferential solvations of both systems were tested and compared. It not only gives some clues about the microheterogeneity of the alcohol system and the structure of the cluster but also helps in advancing our understanding on the behavior and properties of the amphiphilic molecules system such as phospholipids.     

Polymer nano- and microspheres with bumpy and chain-segregated surfaces

Reported is a novel and simple method for the preparation of polymer spheres bearing hemispherical surface bumps where one type of polymer chains concentrates. The method is used to produce spheres with a diameter between approximately 30 and approximately 500 nm. Spheres with chain-segregated bumpy surfaces may find applications in drug delivery and other areas.     

氧气分子参与的乙烯基单体自由基聚合

尽管被公认在自由基聚合中往往起着缓聚、阻聚或链转移的作用,越来越多的结果表明,在某些情况下,如高温、高压,或当某些催化剂存在时,氧气分子(O2)可以参与甚至加速乙烯基单体的自由基聚合。本文综述了上世纪90年代以来,O2参与的乙烯基单体的热/光诱导自由基聚合、化学引发自由基聚合、氧载体催化自由基聚合以及可逆加成-断裂链转移自由基聚合。以上结果表明,在上述情况下,O2,作为一个普通不饱和单体,可以与苯乙烯、甲基丙烯酸甲酯等乙烯基单体形成交替共聚物(聚过氧化物),而此类聚过氧化物均可裂解为自由基。     

Co‐crystallization of hemimellitic acid with 4,4′‐bipyridine forming a pillar‐layered hydrogen‐bonded network

Co‐crystallization of hemimellitic acid (benzene‐1,2,3‐tricarboxylic acid) dihydrate (H₃HMA·2H₂O) with 4,4′‐bipyridine (4,4′‐bpy) affords the 1:1 co‐crystal benzene‐1,2,3‐tricarboxylic acid–4,4′‐bipyridine (1/1), H₃HMA·4,4′‐bpy or C₉H₆O₆·C₁₀H₈N₂. Strong O—H⋯O hydrogen bonds connect the acid mol­ecules to form a one‐dimensional zigzag chain, around which the 4,4′‐bpy components are fixed as arms via O—H⋯N inter­actions, resulting in a ladder motif. Through weak C—H⋯O non‐covalent forces, the resulting acid layers are extended into a three‐dimensional pillar‐layered architecture supported by rod‐like 4,4′‐bpy components. The influence on hydrogen‐bonding models is also discussed, with the discovery of an unexpected inter­action motif that does not follow the routine hydrogen‐bonded hierarchical rule in the construction of an acid–base co‐crystal.     

4-Amino-l,2,4-triazole Resin-supported Palladium Complex as Phosphine-free Catalyst for Suzuki Reaction in Aqueous Phase

1 Introduction The Suzuki cross-coupling reaction is a powerful and versatile method for the generation of unsymme-trical biaryls from arylboronic acids and aryl halides in a single step~([1-3]).However,the reaction is usually performed in the presence of Pd catalyst along with phosphine ligand,which sometimes creates practical problems because organophosphines tend to be expensive,poisonous,and air sensitive.Recently,phosphine-free ligands,such as nitrogen or sulfur-containing ligands~([4-6]) and N-heterocyclic car-benes~([7-12]) have been applied in Suzuki reaction effectively.     

Preparation of a monolith functionalized with zinc oxide nanoparticles and its application in the enrichment of fluoroquinolone antibiotics

This study describes the enrichment ability of ZnO‐modified methacrylic acid‐co‐ethylene dimethacrylate polymer monoliths as stationary phases for the simultaneous determination of antibiotics (ofloxacin, ciprofloxacin, enoxacin, and pefloxacin) combined with high‐performance liquid chromatography. The prepared monolith was characterized by scanning electron microscopy, X‐ray photoelectron spectroscopy, Fourier‐transformed infrared spectroscopy, and thermogravimetric analysis. The polymer monolith microextraction method has been applied to the enrichment of fluoroquinolone antibiotics and satisfactory results were obtained in the analysis of water samples. Compared with the conventional methacrylic acid based monolith, the developed monolith exhibited a higher enrichment capacity because of the introduction of zinc oxide into the preparation process.     

Synthesis of Dispirocyclopentyl‐3,3′‐bisoxindoles via Domino Cycloaddition Reactions of 4‐Dimethylaminopyridinium Bromides with 3‐Phenacylideneoxindoles

The base mediated cycloaddition reactions of 4‐dimethylamino‐1‐phenacylpyridinium bromides with two molecular 3‐phenacylideneoxindoles in methylene dichloride afforded functionalized dispirocyclopentyl‐3,3′‐bisoxindoles in good yields and with high diastereoselectivity. The similar cycloaddition reactions of 1‐(N,N‐dialkylcarbamoylmethyl) and 1‐cyanomethyl 4‐dimethylamino‐pyridinium bromide in refluxing ethanol in the presence of triethylamine also resulted in dispirocyclopentyl‐3,3′‐bisoxindoles with high diastereoselectivity. The stereochemistry of dispirocyclopentyl‐3,3′‐bisoxindoles was elucidated on the basis of ¹H NMR data and single crystal structures.