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.     

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.     

Synthesis of 3-epistrophanthidin and 3-epistrophanthidol

Conclusions 3-Epistrophanthidin and 3-epistrophanthidol have been synthesized from strophanthidin and strophanthidol with yields of 10 and 40%, respectively. The substances synthesized proved to be identical with the new natural aglycones isolated from the seeds ofStrophanthus kombe Oliv.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 1, pp. 57–60, 1970.     

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.     

Influence of the degree of branching of the O-alkyl radical on the anticholinesterase properties of O-alkyl S-n-butyl methylphosphonothioates

Russian Chemical Bulletin -