最近に於ける放射性同位元素の化學への應用について(紹介)

Abstract

We have mainly described recent applications of radio-active isotopes to chemistry since 1947. (1) The preparation and synthesis of radioactive compounds:-In this paragraph, the methods of preparation or synsesis of the labbeled dl-systine, l-serine, nitrosopteroylglutamic acid and many other inorganic and organic compounds were treated. (2) Analytical chemistry:-Here, self-absorption curve, method of measurement of radio-activity, micro-analysis by the radio-chemical method etc. were described. We showed that the lower solubilities, e.g., that of thorium pyrophosphate (6.1×10-5g./liter) etc., cold be measured by the radiochemical method. (3) The mechanism of chemical reactions and exchange reactions:-The mechanism of chemical reactions and exchange reactions would become clear by using the radioactive isotopes. Here we have taken the decomposition of glucose and others as examples. (4) Physical chemistry:- i) The study on the surface, e.g., the determination of surface area by means of radio-chemical method. ii) Measurement of low vapour pressure. By the use of radio-active isotopes, very low vapour pressure, e.g., that of thoriumacetylacetonate (3.2±0.3×10-6m.m. at 1000), can be measured. iii) Determination of ironic transference number in molten salt. PbCl2 was used as salt, and RaD as radio-active indicator. The transference number of Pb between 520° and 680° was 0.1--0.2 and that of Cl, 0.8--0.9. iv) Diffusion coefficient of Cu in the oxidation of Cu-foil. From the distribution of radio-active Cu in the Cu-oxide, diffusion coefficient, D, was found to be 0.358cm./sec. The activation energy for the oxidation of Cu is 39±2 kcal/mol. We also described briefly the counter and the error in the experiment.