Esterification of phthalic anhydride by alcohols in the presence of titanium bis(β-diketonates)

Conclusions In the esterification of phthalic anhydride by 2-ethylhexanol in the presence of titanium bis(-diketonates), the rate constants of the reaction increase with decreasing stability of the chelate. The relation of the rate constant of the reaction of phthalic anhydride with normal C₆-C₉ alcohols catalyzed by bis (acetylacetonato) dibutoxytitanium and butyl orthotitanate in a medium of the corresponding diesters is extremal in nature because of the different degree of hydrolysis of the catalyst during esterification.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1247–1250, June, 1989.     

Condensation of o-phenylene diamine and substituted acroleins to form macroheterocycles

The reaction of o-phenylene diamine with -alkoxy-, -dimethylamino-, and -acetoxy--alkyl- or -arylacroleins has been studied. A new synthesis of 7,16-diaryl[5,14]dihydro[b,i]dibenzo-[5,9,14,18]tetraaza[14]annulenes was developed, and the syntheses of 5,14-dihydro[b,i]dibenzo[5,9,14,18]tetraaza-[14]annulene and 7,16-dialkyl[5,14]dihydro[b,i]dibenzo[5,9,14,18]tetraaza[14]-annulenes were improved. 5,14-Dihydro[b,i]dibenzo[5,9,14,18]tetraaza[14]-annulenes were synthesized with various substituents in the benzene rings and at positions 7 and 16.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 376–381, March, 1987.     

N-2-(2-pyridyl)ethyl chitosan: Synthesis in gel and sorption properties

A procedure was developed for preparing a new heterocyclically substituted chelating aminopolymer, N-2-(2-pyridyl)ethyl chitosan, by direct addition of 2-vinylpyridine to chitosan under the conditions of synthesis in gel. The resulting polymer has the degree of substitution of up to 1. The ability of the samples obtained to sorb transition and noble metal ions was evaluated.     

Investigation of the structure of chitosan hybrid systems by pH-sensitive nitroxyl radical

Hybrid organo-inorganic materials based on the chitosan-SiO₂, chitosan-Al₂O₃, and chitosancellulose systems are prepared. The structure of the surface is studied by means of EPR spectroscopy using the stable pH-sensitive nitroxyl radical, 4-dimethylamino-2-ethyl-5,5-dimethyl-2-pyridine-4-yl-2,5-dihydro-1H-imidazole-1-oxyl as adsorbed probe molecules, and the processes that occur during the formation of hybrid materials are considered.     

Synthesis of poly[N-(2,3-dihydroxypropyl)aminostyrene], a new sorbent for boron(III) ions

A procedure was developed for preparation of poly[N-(2,3-dihydroxypropyl)aminostyrene] via successive stages of nitration, reduction, and glycidol treatment of polystyrene, which gives the polymer with a maximal degree of functionalization. The composition and structure of the intermediates and end products of the polymer-analogous reactions were characterized by elemental analysis, IR spectroscopy, and solid-state ¹³C NMR spectroscopy. The sorption characteristics of poly[N-(2,3-dihydroxypropyl)aminostyrene] toward boroncontaining ions were assessed.     

Synthesis in a gel and sorption properties of N-2-sulfoethyl chitosan

A new procedure was developed for preparation of chelate amino-containing polymer N-2-sulfoethyl chitosan by synthesis in a gel through the reaction between chitosan and sodium 2-bromoethanesulfonate, yielding a polymer with the degree of substitution of up to 0.5. The structure of the resulting polymers was confirmed by ¹H NMR spectroscopy. The sorption characteristics with respect to transition and alkaline-earth metal ions were determined for the cross-linked polymers.