The Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences (hereinafter referred to as RAS) was founded in 1988 on the basis of the Department of Special-Purity Substances and Volatile Metal Compounds of the Institute of Chemistry of the USSR Academy of Sciences. The founder and the first Director of the Institute was Grigory Grygorievich Devyatykh (1918 – 2005), Academician of RAS, Hero of Socialist Labor, Laureate of Lenin prize and the Prize of the Russian Federation Government.
The setting up of the Institute as an academic institution was the natural result of the success of Nizhny Novgorod school in the development and analysis of high-purity substances. Investigations on this scientific issue were started by G.G. Devyatykh in 1956 at the Chemical Faculty of N.I. Lobachevsky Gorky State University. Up to 1963 the work was carried out by the Department of Inorganic Chemistry and the Laboratory of Mixture Separation of the Research Chemistry Institute at Gorky State University. From 1964 this research area started to develop at the Laboratory of Polymer Stabilization of the USSR Academy of Sciences. In 1968 the laboratory turned into the Institute of Chemistry of the USSR Academy of Sciences.
|Founder of the IChHPS of RAS
G.G. Devyatykh, Academician
Further follows the synopsis of the major contributions of IChHPS of RAS to the fundamentals of high-purity substances chemistry.
Development of the scientific fundamentals for the processes of mixture separation and production of high-purity substances. Development of ultrapurification methods for substances of different chemical groups
The physical and chemical fundamentals have been developed for the production of high-purity substances of different chemical groups. Statistical and thermodynamic techniques have been suggested to calculate the separation factor for liquid-vapor and crystal-liquid equilibria making it possible to theoretically estimate the value of the separation factor. Theoretical fundamentals have been developed for ultrapurification of substances in counter-flow multi-stage processes, i.e., rectification, counter-flow crystallization from the melt, zone recrystallization.
The original designs of columns were developed and their efficiency has been manifested in ultrapurification of specific substances.
The behavior of suspended nano-particles as a specific group of impurities has been studied during ultrapurification of volatile substances. It has been found as drastically different from the behavior of impurities forming a true solution with the purified substance. A new highly efficient method has been suggested and implemented for ultrapurification from suspended particles, i.e., film rectification with vapor superposition of temperature gradient (thermal distillation).
Development of methods for analysis of high-purity substances
The work on the production of high-purity substances was accompanied by the simultaneous or advanced development of the quantitative and qualitative determination of impurities. High-sensitive techniques of analysis were developed based on source and laser mass spectrometry, photoelectric spectroscopy, chemical atomic-emission and atomic absorption analysis, electron microscopy, X-ray microanalysis, IR- and UV-spectroscopy, gas and liquid chromatography, laser ultramicroscopy. It made it possible to thoroughly characterize the impurity composition of high-purity substances and materials of different chemical groups. Actually all the major impurities can be determined in solids with concentration up to 10-10 %; the impurities in elemental and molecular form in volatile substances from 10-1 % to 10-8 %.
Production, analysis and investigation of the properties of high-purity substances. Development of new materials based on high-purity substances
A great amount of work was conducted on the investigation of the properties of high-purity substances. Explosion and fire hazards of volatile hydrides and organo-metallic compounds were investigated. Heat capacity and heat conductivity were measured for a number of high-purity substances as well as the electrical conduction of metals in the low-temperature region; the effect of impurities upon these properties was investigated.
Development of scientific foundations for the technology of high-purity substances materials and functional units on their basis
The open exchange of information and the joint investigations made it possible to realize a unique scientific project of collecting and attesting of samples of the purest substances and materials produced both in Russia and abroad. The project was implemented within the framework of the Permanent Collection Exhibition of Special-Purity Substances set up by the decision of the Presidium of the USSR Academy of Sciences in 1974 with the goal of getting objective information on the state of the problem of high-purity substances. During the period of work of 35 years a unique collection of high-purity substances has been acquired including more than 600 samples; their impurity content was investigated and the information-calculation system «High-Purity Substances and Materials» was created comprising the data base of ~ 42000 impurity-determinations. According to the data of the Collection Exhibition among the purest samples of chemical elements only 4% has the total content of impurities at the level of 10-6 at. % and, approximately, in one-third of chemical elements the total content of impurities is close to 10-3 at. %. The absolute content of impurities even in the purest solids is 1015-1016 at./cm3. This level of impurities does not preclude the effect of impurities upon substance properties. It is known that impurities and structural defects contribute greatly to the quantitative value of the investigated properties. The increase of the degree of purity serves to attain a state when the defect contribution to the investigated property will be equal to the value of impurity contribution. The lower boundary of impurity sensitivity characteristic of the «property of high-purity substance – impurity content» dependence corresponds to this content of impurities. Determination of these values for all impurity-sensitive properties is the main subject of the chemistry of high-purity substances. The main direction of the investigations at the IChHPS of RAS is advancing to a higher level of purity both in the currently purest substances and in less pure substances. Production of purer substances can lead to the detection of new properties or to distinct manifestation of the known properties of substances.