Benzidine and diphenylamine radical formation on the surface of NaY-zeolite and γ-alumina with and without MoO3

Solutions of benzidine and diphenylamine in benzene produce cation radical on the surface of zeolite, γ-alumina, MoO₃ and MoO₃ doped γ-alumina and zeolite. MoO₃ doped zeolite behaved much differently than V₂O₅ doped zeolite in presence of benzidine or diphenylamine in benzene.     

Preparation and application of dense poly(phenylene oxide) membranes in pervaporation

Dense flat-sheet membranes were prepared from poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) using the casting solvents chloroform and 1,1,2-trichloroethylene. X-ray diffraction, tapping mode atomic force microscopy (TM-AFM), and contact angle studies were used to characterize the membranes. The surface energy and the solubility parameters of the PPO membranes were determined from the measured contact angles and compared with the predicted ones from the group contribution method. Swelling experiments and pervaporation separation of methanol from its mixture with ethylene glycol over the entire range of concentration, 0-100%, were conducted using these membranes. Flory-Huggins theory was used to predict the sorption selectivity. The results are discussed in terms of the solubility parameter approach and as function of the morphological characteristics of the membranes. It was found that PPO membranes prepared with chloroform exhibited better pervaporation performance than PPO membranes prepared with 1,1,2-trichloroethylene.     

Benzidine and diphenylamine radical formation on the surface of NaY-zeolite and γ-alumina with and without V2O5

Solutions of benzidine and diphenylamine in benzene produce cation radicals on the surface of zeolite, -alumina and V₂O₅ doped alumina and zeolite. The sequence of the electron acceptor site strength on the surface is as follows:     

Copper(II), nickel(II) and cobalt(II) complexes of pyridyl and quinolylhydrazones of isatin and methylisatin: Ligand dependent stereochemistry

Summary [M^II(Lig)X] (M = Cu^II, Ni^II or Co^II and Lig = deprotonated pyridylhydrazone, (IPH-H), quinolylhydrazone of isatin (IQH-H) andN-methylisatin (MIQH-H)) have been characterized by magnetic susceptibility measurements, optical spectra and infrared spectral studies. [M^II(IPH-H)Cl] (M = Ni^II and Co^II) are tetrahedral while [M^II(MIQH-H)X] (M = Ni^II or Co^II and X = Br or Cl), [Ni^II(IQH-H)Br] and [Cu^II(IPH-H)Cl] are planar.     

Insertion of zeolite in sol-gel made catalytic material: an EPR study

Incorporation of zeolite to catalyst base-supports generally endows them with improved catalytic properties; especially those related to selectivity and activity. These effects are due to the stronger than normal acidity of zeolites and their molecular sieve effect. Such properties alter notoriously the way in which metals incorporate into a crystalline sol-gel catalytic matrix. Most noticeable effects on the surface as per EPR analysis occur upon incorporation of copper as metal catalyst when ZSM-5 zeolite is added, then when adding β-zeolite and finally when using Y-zeolite. This revised version was published online in June 2006 with corrections to the Cover Date.     

Colour changes in the uncatalyzed and Ag+ catalyzed oxidation of aromatic amines by persulphate ion

Summary A scheme has been proposed for the identification of some of the aromatic amines, viz., aniline, ethyl and methyl aniline, diethyl and dimethyl aniline, - and -naphthylamine, o-, m- and p-toluidine, o-, m- and p-anisidine, m- and p-phenetidine, o-, m- and p-phenylenediamine, carbazole, benzidine, o-tolidine, quinoline and iso-quinoline, p-xylidine and diphenylamine. It is based on the reaction of an aqueous persulphate solution with an alcoholic solution of the amine.

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Zusammenfassung Eine systematische Identifizierung einiger aromatischer Amine aufgrund der Oxydation mit Persulfatlösung wird beschrieben. Folgende Verbindungen werden dabei berücksichtigt: Anilin, Äthyl- und Methylanilin, Diäthyl- und Dimethylanilin, - und -Naphthylamin, o-, m- und p-Toluidin, o-, m- und p-Anisidin, m- und p-Phenetidin, o-, m- und p-Phenylendiamin, Carbazol, Benzidin, o-Tolidin, Chinolin und Isochinolin, p-Xylidin und Diphenylamin.

     

Recent advances in continuous flow synthesis of heterocycles

In the current scenario, flow chemistry is emerging as a significant technology in the field of organic synthesis. This miniaturized protocol including microreactors facilitates excellent heat transfer, low solvent wastage, lesser reaction time, a safer environment for reagent handling and appreciable yields of desired products. Thus, this “enabling technology” has a great scope in the synthesis and preparation of a variety of heterocycles that require toxic reagents as starting materials. This review discusses the recent advances (2020–2021) in continuous flow strategy for synthesis and derivatization of variety of heterocyclic entities, of different ring size, using different approaches. This also highlights the advantages of different combined techniques like Microwave assisted heating, electrochemical flow cell, LED light source, NMR and FT-IR analysis, etc., that enables utilization of various mechanisms and real-time monitoring of reactions leading to improved results.

Graphic abstract