Sorption Recovery of Transplutonium Elements from Nitric Acid Solutions with Arsenazo Group Reagents

Sorption recovery of actinides and lanthanides from nitric acid solution with arsenazo group reagents, activated carbon modified with these reagents, and chelating sorbents containing arsenazo functional groups was studied.     

Fabrication and Characterization of Novel Salicylic Acid Sensors Using Different Reagents (Ferric and Copper)

Abstract

Fabrication of optical fiber salicylic acid (SA) sensors based on immobilization of ferric(III) nitrate and copper(II) acetate on Dowex‐50x8 is presented in this paper. The SA forms a stable purple complex with immobilized Fe³⁺ at pH 2.1 with a response time of 10 min while it forms a stable yellowish green complex with immobilized Cu²⁺ at pH 6.5 with a response time of 8 min. The reflectance spectra of the sensors were measured by using an optical fiber spectrophotometer. The results showed these SA sensors have maximum reflectance at 786 nm and 725 nm for SAFe complex and SACu complex, respectively. The useful dynamic response ranges are 0.02–0.50 g/L (SAFe) and 0.40–1.40 g/L (SACu). These complexes are stable for more than 24 hours. A good reproducibility (0.90%— SAFe; 0.86%— SACu) of measurement was obtained with these sensors.     

A Review of Manganese(III) (Oxyhydr)Oxides Use in Advanced Oxidation Processes

The key role of trivalent manganese (Mn(III)) species in promoting sulfate radical-based advanced oxidation processes (SR-AOPs) has recently attracted increasing attention. This review provides a comprehensive summary of Mn(III) (oxyhydr)oxide-based catalysts used to activate peroxymonosulfate (PMS) and peroxydisulfate (PDS) in water. The crystal structures of different Mn(III) (oxyhydr)oxides (such as α-Mn₂O₃, γ-MnOOH, and Mn₃O₄) are first introduced. Then the impact of the catalyst structure and composition on the activation mechanisms are discussed, as well as the effects of solution pH and inorganic ions. In the Mn(III) (oxyhydr)oxide activated SR-AOPs systems, the activation mechanisms of PMS and PDS are different. For example, both radical (such as sulfate and hydroxyl radical) and non-radical (singlet oxygen) were generated by Mn(III) (oxyhydr)oxide activated PMS. In comparison, the activation of PDS by α-Mn₂O₃ and γ-MnOOH preferred to form the singlet oxygen and catalyst surface activated complex to remove the organic pollutants. Finally, research gaps are discussed to suggest future directions in context of applying radical-based advanced oxidation in wastewater treatment processes.     

Chemical Structure,Porous Morphology,and Sorption Properties of Adsorbents Produced from Organic Technogenic Substrates (A Review)

Russian Journal of General Chemistry - The review provides information on the Porous structure and sorption properties of carbon and carbon-inorganic sorbents obtained from organic technogenic...     

Sorption and Catalytic Activity of Adsorbent-Catalyst Based on Montmorillonite Modified with Cr(III) and Cu(II) Mixed Oxides

The sorption properties of mixed adsorbent-catalyst based on high-silica zeolite and montmorillonite modified with mixed oxides of Cr(III) and Cu(II) with respect to organic compounds of various classes were studied, and the optimal dynamic conditions of its operation were determined.     

Sorption of CO2 from Humid Gases on Potassium Carbonate Supported by Porous Matrix

Kinetics of sorption of carbon dioxide on potassium carbonate supported by different porous matrices was studied in a flow reactor at 40°C. The structural and chemical changes of potassium carbonate-aluminum oxide composite sorbents were studied by powder X-ray diffraction, thermogravimetry, and low-temperature nitrogen sorption.     

Synthesis of MAPA Reagents and 2-Alkyl(aryl)aminopyridines from 2-Bromopyridine Using the Goldberg Reaction

A short and economical synthesis of various 2-methylaminopyidine amides (MAPA) from 2-bromopyridine has been developed using the catalytic Goldberg reaction. The effective catalyst was formed in situ by the reaction of CuI and 1,10-phenanthroline in a 1/1 ratio with a final loading of 0.5–3 mol%. The process affords high yields and can accommodate multigram-scale reactions. A modification of this method provides a new preparation of 2-N-substituted aminopyridines from various secondary N-alkyl(aryl)formamides and 2-bromopyridine. The intermediate aminopyridine formamide is cleaved in situ through methanolysis or hydrolysis to give 2-alkyl(aryl)aminopyridines in high yields.     

Reductive C2‐Alkylation of Pyridine and Quinoline N‐Oxides Using Wittig Reagents

The ability to alkylate pyridines and quinolines is important for their further development as pharmaceuticals and agrochemicals, and for other purposes. Herein we describe the unprecedented reductive alkylation of pyridine and quinoline N‐oxides using Wittig reagents. A wide range of pyridine and quinoline N‐oxides were converted into C2‐alkylated pyridines and quinolines with excellent site selectivity and functional‐group compatibility. Sequential C?H functionalization reactions of pyridine and quinoline N‐oxides highlight the utility of the developed method. Detailed labeling experiments were performed to elucidate the mechanism of this process.     

柴油机尾气净化催化剂的最新研究进展

柴油机尾气排放的污染物已经引起了严重的环境污染问题,催化净化技术是柴油机尾气污染治理必不可少和最有效的处理技术之一,而高效催化剂的研制和开发是催化净化技术的核心.本文以柴油机尾气中最难处理的两种污染物NOx和碳烟颗粒(PM)的催化处理技术为主线,综述了NOx的催化还原(选择性催化还原(SCR)和贮存还原(NSR))催化剂、碳烟的催化燃烧催化剂、NOx和碳烟颗粒同时消除的催化剂及柴油机尾气四效催化剂的最新研究进展,并总结性地提出了目前该研究方向存在的主要问题和发展方向.     

Sorption of molybdenum(VI) from mineral salt solutions

Changes in the ionic forms of molybdenum and conditions of sorption on the anionite AV-17 × 8 from mineral salt solutions at concentrations of 0.05–2 N and pH of medium 1–6 were revealed.     

载体试剂在有机合成中应用的研究(Ⅱ)——芳香醚的合成

某些芳香族混醚如对硝基苯基间甲苯醚(甲草醚)、2,4-二氯苯基-4'-硝基苯基醚等均是商品化的除草剂。近年来,相转移催化法合成醚类已有报导。     

Reductive Elimination of Bromine from 1,2-Dibromoalkanes Using Organometallic Reagents

Organocuprate(I) reagents are now being widely used for highly selective substitution reactions¹ with alkyl,² alkenyl,² aryl,² and acyl³ halides and with α,α'-dihaloketones.⁴ Organocopper interaction with 1,2-dihaloalkanes is of interest because two main reaction pathways may be expected: (a) replacement of both halogens by organic groups and (b) reductive elimination of halogen to form alkenes.⁵ We report here that various types of 1,2-dibromides react with lithium dialkyl-cuprate(I) reagents under exceedingly mild conditions to give alkenes exclusively (Eq. 1).     

快速气相色谱法测定汽车工业废气中芳烃排放量

采用气体直接进样及快速程序升温气相色谱法,能在８０ｓ内快速,简单地测定废气中芳烃等多种组分的含量。在本方法中,芳烃的最低检出浓度为０．１ｍｇ／ｍ６３,该方法允在两周内测定了汽车喷漆车间４８个排气口的５７６个样品,具有简单,快速,灵敏,实用等优点,特别适合于涂装工业气体稀释溶剂样品的测定。     

Sorption of radiocobalt(II) from aqueous solutions to Na-attapulgite

The sorption of Co(II) on Na-attapulgite as a function of contact time, solid content, pH, ionic strength, foreign ions, fulvic acid (FA) and temperature under ambient conditions was studied. The kinetic of Co(II) sorption on Na-attapulgite was described well by pseudo-second-order model. The sorption of Co(II) on Na-attapulgite was strongly dependent on pH and ionic strength. The sorption of Co(II) was mainly dominated by outer-sphere surface complexation and/or ion exchange at low pH, whereas inner-sphere surface complexation or surface precipitation was the main sorption mechanism at high pH values. The presence of FA did not affect Co(II) sorption obviously at pH <7, and a negative effect was observed at pH >7. The Langmuir and Freundlich models were used to simulate the sorption data at different temperatures, and the results indicated that the Langmuir model simulated the data better than the Freundlich isotherm model. The thermodynamic parameters (∆G°, ∆S°, ∆H°) calculated from the temperature-dependent sorption isotherms indicated that the sorption of Co(II) on Na-attapulgite was an endothermic and spontaneous process. The results suggest that the attapulgite sample is a suitable material in the preconcentration and solidification of radiocobalt from large volumes of aqueous solutions.