Hydrolysis study of organic acid anhydrides by differential thermal analysis-I Pyromellitic dianhydride

A technique for following the hydrolysis of pyromellitic acid dianhydride (PMDA) by differential thermal analysis (DTA) is described. On exposure of PMDA to moisture, an endothennic peak is initiated between 190 and 200 degrees . As the degree of hydrolysis increases, this peak becomes more intense and shifts to higher temperatures. The formation of pyromellitic acid (PMA) during the hydrolysis of PMDA can be determined qualitatively by DTA.     

Reaction of perfluoroisobutylene with potassium thiocyanate

Conclusions The authors obtained perfluoroisobutenyl isothiocyanate by reacting perfluoroisobutylene with potassium thiocyanate, and studied some of its properties.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1176–1178, May, 1969.     

Determination of Samarium in rocks by epithermal neutron-activation analysis

Summary A non-destructive neutron-activation method for the determination of samarium in rocks, based on activation with epithermal neutrons, is described. By this means the formation of¹⁵³Sm, as compared to most interfering radionuclides, is considerably higher than by thermal neutron activation. The precision of the method is 2–3% in the range of 3–25 ppm, and the sensivity is about 0,1 ppm. Results are presented for some standard rocks. The influence of other rare earth nuclides on the measurement of the 41 KeV X-ray of¹⁵³Sm has been investigated.

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Zerstörungsfreie Bestimmung von Samarium in Gesteinen durch Aktivierungsanalyse mit epithermischen Neutronen

Zusammenfassung Die Bildung von¹⁵³Sm ist hierbei im Vergleich zu den meisten störenden Radionukliden beträchtlich größer als bei der Aktivierung mit thermischen Neutronen. Die Präzision des Verfahrens beträgt 2–3% im Bereich von 3–25 ppm, die Empfindlichkeit etwa 0,1 ppm. Für einige Standardgesteine werden die Ergebnisse angeführt. Der Einfluß anderer Nuklide Seltener Erden auf die Messung der 41 keV Röntgenstrahlung von¹⁵³Sm wurde untersucht.

     

The effect of a magnetic field on the singlet/triplet ratio in geminate ion recombination

Excited state formation by ion recombination in solutions of fluorene in squalene has been studied by pulse radiolysis at the center of a large electromagnet. The products of the slower part of the ion recombination are affected by an applied magnetic field. The fluorescence yield increases by a factor of about 1.5 whereas the triplet yield decreases.     

Radiation Effects on Concentrated Potassium Hexacyanoferrate(III) Solutions

The neutron irradiated potassium hexacyanoferrate(III) solutions were analyzed for Fe(CN)₆^4?, Fe(CN)₆^3?, and Prussian blue. The retention values (1.1%) were constant throughout the pH and concentration ranges studied, and did not change with the length of irradiation. The complex behavior of the radiochemical yield of the Fe(CN)₆^4? and Prussian blue was attributed to the competition of the various reactions involved in the irradiation.     

Reactivity of phenyl esters of phosphorus acids in alkaline hydrolysis

Conclusions A study was made of the kinetics of the alkaline hydrolysis of some phenyl esters of phosphorus acids. An estimate was made of the contribution made by the induction effect and the p–d conjugation of the phenoxyl group to the free activation energy of the alkaline hydrolysis of the investigated esters.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2794–2796, December, 1972.