Mössbauer study of iron reduction in hematite containing mineral originated from Aswan area in Egypt

Mössbauer spectroscopy was used to study iron reduction in mineral originated from Aswan area in Egypt. The Mössbauer spectra of samples heat treated at 1000 °C in hydrogen atmosphere show a gradually reduction process of hematite. The main phase of sample aged for 1 h is magnetite, while alpha-iron as well as some silicates and wustite type oxide can be detected in sample aged for 3 h. Further aging of sample results in dissolution of alloying elements /Si, Al/, being present in the samples. This process starts already in samples aged at 1000 °C for 4 h, but it is more expressive in minerals heat treated at 1200 °C or 1300 °C, when all paramagnetic phases disappeared.     

Acetals of lactams and acid amides. 53. Eamidines in the synthesis of pyridine and pyrimidine

The reaction of -cyano--aminocrotonic ester with DMFA diethylacetal gives 1-ethoxycarbonyl-1-cyano-2-(N-dimethylaminomethylene)-amino-4-dimethylaminobutadiene, the reaction of which with ammonium acetate and amines leads to 4-methylenepyrimidine derivatives. Condensation of -cyano--aminocrotonic ester with dimethylacetamide dieethylacetal gave 2-(ethoxycarbonylcyano)methylene-4-dimethylamino-6-methylpyridine. It was found that in an alkaline medium, 1-benzyl-4-(ethoxycarbonylcyano) methylenepyrimidine recyclizes into 1-benzyl-3-cyano-4-amino-2-pyridone.For Communication 52, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1109–1114, August, 1988.     

Mass spectra of arylalkylpyridines

The basic principles of the mass-spectral fragmentation of arylalkylpyridines that contain substituents in various positions were established. The principle ions that can be used in Chromatographic mass-fragmentographic analysis in the study of liquid-crystal compositions were determined for each specific case.Communication 1 of the series Mass spectra of liquid crystalsTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1509–1513, November, 1987.     

Force fields and vibrational spectra of M2O and MOH (M = Li,Na) molecules according to data from nonempirical MO-LCAO-SCF calculations

The geometric structure, force fields, and vibrational spectra of M₂O and MOH (M=Li, Na) molecules have been investigated. The size of the d basis on the oxygen atom has a significant influence only on the frequency of the deformation vibration ₃. Experimentally unknown constants of the molecules considered have been evaluated.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 22, No. 6, pp. 724–728, November–December, 1986.     

Influence of the crystallinity of pentasil-type zeolites on their acidity

The acid properties of intermediate products in crystallization of pentasil-type zeolites have been investigated using programmed thermal desorption of ammonia and adsorption of pyridine. It was found that acidity increases with increasing crystallinity due to proton-donor centers. A correlation was established between this change in acidity and methanol TPSR data.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 31, No. 1, pp. 48–51, January–February, 1995.     

Thermodynamics of condensation of phthalonitrile with m-phenylenediamine

Conclusions The reaction of phthalonitrile condensation with m-phenylenediamine is thermodynamically allowed at temperatures from 250° to 500°K, and its equilibrium is almost completely shifted toward the formation of the macroheterocycle.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 779–787, April, 1984.