The Removal of Particles from Oils by Nonionic Surfactants

The separation of particulate material from a dispersion of particles in an oil can be effected by transport of the particles through the bounding oil interface in a process mediated by surfactant. When the oil phase containing particles is contacted with an aqueous phase, the transport process through the interface is resisted by a capillary force which depends on the interfacial tension and on the contact angle for the three-phase system. It is shown how the addition of a judiciously-chosen nonionic surfactant to a model system of carbon particles in n-alkanes can bring about near-complete transfer of the particles to the aqueous phase. The underlying mechanisms for the transport process are discussed. Some implications for systems of practical importance are discussed.     

基于二肽的相选择胶凝剂对水中油污和有毒染料的清污性能

设计合成了一系列相选择胶凝剂(3a-3e),并通过¹H和¹³C核磁共振波谱和质谱对其结构进行了表征。 在有机溶剂和水的混合体系中对目标化合物进行相选择凝胶性能试验,结果表明化合物3c在粉末状态下表现出出色的相选择胶凝能力,在室温下可通过摇晃从油水两相体系中快速除去苯、甲苯、二甲苯和汽油。 另外,实验证明以3d-苄醇凝胶作为吸附剂可以实现有毒染料溶液的有效吸附,而且通过紫外-可见光谱实验可以对其清除效果进行量化。 操作简单和高效除污等优点表明这些二肽胶凝剂在污水纯化处理中具有广阔的应用前景。     

Nickel-Catalyzed Thiolation of Aryl Nitriles

A nickel-catalyzed thiolation of aryl nitriles has been developed to access functionalized aryl thioethers. The ligand dcype (1,2-bis(dicyclohexylphosphino)ethane) as well as the base KO^tBu (potassium tert-butoxide) are essential to achieve this transformation. This scalable and practical process involves both a C−C bond activation and a C−S bond formation. Furthermore, this reaction shows a high functional-group tolerance and enables the late-stage functionalization of important molecules.     

微生物铁氧化还原作用对水中砷锑去除影响的研究进展

砷锑污染在全球领域广泛存在,与常规的铁氧化物相比,微生物铁氧化生成的含Fe(Ⅲ)矿物对水中砷/锑(As/Sb)具有更强的吸附能力,并因其高效、实用和环境友好而具有广阔的应用前景,但微生物铁还原也可能导致被吸附的As/Sb再次释放。本文综述了微生物铁氧化还原作用对As/Sb去除影响的研究进展,归纳了铁矿物“合成-溶解-转化”的微生物循环过程以及该循环伴随的水中As/Sb固定、溶解与转化机理,整合了微生物合成Fe(Ⅲ)矿物的矿物学性质、对As/Sb固定的热动力学规律和络合机制,总结了微生物合成Fe(Ⅲ)矿物对As/Sb去除的影响因素,基于该研究的现存问题展望了利用微生物铁氧化还原作用去除As/Sb的发展方向。     

Efficient Co-Catalyzed Double Hydroboration of Nitriles: Application to One-Pot Conversion of Nitriles to Aldimines

The commercially available and bench-stable Co(acac)₂/dpephos system is employed as a precatalyst for selective and efficient room temperature hydroboration of organic nitriles with HBPin to produce a series of N,N-diborylamines [RN(BPin)₂], which react in situ with aldehydes to give aldimines. Formation of aldimines from N,N-diborylamines does not require a dehydrating agent, is applicable to a wide range of N,N-diborylamine and aldehyde substrates and is highly chemoselective, being unaffected by various common functional groups, such as alkenes, alkynes, secondary amines, ketones, esters, amides, carboxylic acids, pyridines, nitriles, and nitro compounds. The overall transformation represents a synthetically valuable approach to aldimines from nitriles and can be performed in a sequential one-pot manner, tolerating ester, lactone, carboxamide and unactivated alkene functionalities.     

Straightforward Conversion of Alcohols into Nitriles

The reaction of various alcohols with cyanogen bromide, triphenylphosphine, and a base afforded the corresponding nitrile in satisfactory yields.     

Reactions of Amidoximes with Metal-Activated Nitriles

Metal-mediated reactions of amidoximes with nitrile ligands are discussed and recent works of the author are considered to allow the reader to better understand the amidoxime reactivity patterns. General routes of activation of amidoxime and nitrile substrates in the studied reactions are considered. Reactions employing amidoximes as HO- and HN-nucleophiles, as well as reactions of amidoximes with nitrile ligands leading to heterocyclic systems are discussed.     

Removal of Chromium(VI) from Groundwater Using Oil Shale Ash Supported Nanoscaled Zero-valent Iron

Oil shale ash(OSA) supported nanoscaled zero-valent iron(OSA-nZVI) was used as a rapid and efficient reductant for Cr(VI) reduction. The optimal mass ratio of nZVI to OSA and the optimal dosage were explored. The effects of initial pH, reaction temperature, initial Cr(VI) concentration, and common cations and anions in groundwater on Cr(VI) reduction were determined in batch experiments. The results show that the optimum initial pH is 5.0. The reaction temperature has a positive effect on Cr(VI) reduction while the real groundwater has a negative effect. Additionally, 84.22% Cr(VI) was still reduced by 3 g/L OSA-nZVI(1:2)(mass ratio of OSA to Fe⁰ was 1:2) within 120 min for 50 mg/L Cr(VI) under conditions of 10℃ and unadjusted pH.     

Intercalates of Vanadyl Phosphate with Aliphatic Nitriles

Intercalates of vanadyl phosphate with aliphatic nitriles (acetonitrile, propionitrile, butyronitrile, valeronitrile and hexanenitrile) were prepared and characterized by X-ray powder diffraction, thermogravimetric analysis, IR and Raman spectroscopies. The basal spacings of all the intercalates prepared are practically identical. The nitrile intercalates (except acetonitrile) contain one nitrile molecule per formula unit. The nitrile molecules are anchored to the host layers by an N–V donor-acceptor bond and their aliphatic chains are parallel to the host layers. The acetonitrile intercalate contains two guest molecules per formula unit. Only half of them can be bonded to the vanadium atom, the second half is probably anchored by van der Waals interaction. The intercalates prepared are moisture-sensitive and the guest molecules are easily replaced by water molecules.     

A Review on Optimization Production and Upgrading Biogas Through CO2 Removal Using Various Techniques

Biogas from anaerobic digestion of organic materials is a renewable energy resource that consists mainly of CH₄ and CO₂. Trace components that are often present in biogas are water vapor, hydrogen sulfide, siloxanes, hydrocarbons, ammonia, oxygen, carbon monoxide, and nitrogen. Considering the biogas is a clean and renewable form of energy that could well substitute the conventional source of energy (fossil fuels), the optimization of this type of energy becomes substantial. Various optimization techniques in biogas production process had been developed, including pretreatment, biotechnological approaches, co-digestion as well as the use of serial digester. For some application, the certain purity degree of biogas is needed. The presence of CO₂ and other trace components in biogas could affect engine performance adversely. Reducing CO₂ content will significantly upgrade the quality of biogas and enhancing the calorific value. Upgrading is generally performed in order to meet the standards for use as vehicle fuel or for injection in the natural gas grid. Different methods for biogas upgrading are used. They differ in functioning, the necessary quality conditions of the incoming gas, and the efficiency. Biogas can be purified from CO₂ using pressure swing adsorption, membrane separation, physical or chemical CO₂ absorption. This paper reviews the various techniques, which could be used to optimize the biogas production as well as to upgrade the biogas quality.     

One-Step Synthesis of Methyl Esters from Nitriles

Polyphosphate ester that contains methanol easily converts aromatic and alkyl nitriles in one step and in high yield to the corresponding methyl ester at 120° – 150°c.     

Microbial Sensing and Removal of Heavy Metals: Bioelectrochemical Detection and Removal of Chromium(VI) and Cadmium(II)

The presence of inorganic pollutants such as Cadmium(II) and Chromium(VI) could destroy our environment and ecosystem. To overcome this problem, much attention was directed to microbial technology, whereas some microorganisms could resist the toxic effects and decrease pollutants concentration while the microbial viability is sustained. Therefore, we built up a complementary strategy to study the biofilm formation of isolated strains under the stress of heavy metals. As target resistive organisms, Rhizobium-MAP7 and Rhodotorula ALT72 were identified. However, Pontoea agglumerans strains were exploited as the susceptible organism to the heavy metal exposure. Among the methods of sensing and analysis, bioelectrochemical measurements showed the most effective tools to study the susceptibility and resistivity to the heavy metals. The tested Rhizobium strain showed higher ability of removal of heavy metals and more resistive to metals ions since its cell viability was not strongly inhibited by the toxic metal ions over various concentrations. On the other hand, electrochemically active biofilm exhibited higher bioelectrochemical signals in presence of heavy metals ions. So by using the two strains, especially Rhizobium-MAP7, the detection and removal of heavy metals Cr(VI) and Cd(II) is highly supported and recommended.     

One-Pot Conversion of Aldehyde Sodium Bisulfites into Nitriles

Direct conversion of aldehyde sodium bisulfites to the corresponding nitriles can be easily performed by the reaction of an aldehyde sodium bisulfites with a slight execss of hydroxylamine hydrochloride in refluxing toluene and in the presence of 1.0 equivalents of pyridine as catalyst.     

A Facile One-Pot Conversion of Aldehydes into Nitriles

A facile one-pot synthesis of nitriles starting with aldehydes has been developed employing hydroxylamine hydrochloride in dimethylsulfoxide at 100°C.