(1) By passing carbon monoxide gas through the dilute aqueous solution of chloroplatinic acid, a red-coloured colloidal solution was obtained. (2) The red sol was more stable than the ordinary black platinum sol against electrolytes. (3) The red sol changed to the black one evolving some gas bubbles by the action of air, oxygen, hydrogen peroxide, alcohols, and aceton, or by the process of evacuation or heating. (4) The action of bromine water on the red sol is described. (5) The change of the electrical conductivity was measured in the process of formation of the red sol. (6) The structure of the colloidal particles of the red sol is discussed. They consist, probably, of groups of platinum carbonyl molecules.
(1) The Raman spectra of the following substances have been measured: α-methyl-furan, α-furfuryl alcohol, α-furfuryl acetate, furfural, α-furoyl chloride, methyl α-furoate, ethyl α-furoate, α-furfuracrylic acid, ethyl α-furfuracrylate, and tetrahydro-α-furfuryl alcohol. (2) The frequencies of Δν, 625 (or 650), 888, 925, 1021, 1081, 1153, 1232, 1390, 1460 (or 1480), 1507, 1575 (or 1605), 3122, 3153cm.−1,are observed as the characteristic lines of the α-mono-derivatives of furan. (3) The frequencies of Δν, 1460 (or 1480) and 1572 cm.−1, are observed in the type of (Remark: Graphics omitted.), while those of 1507 and 1605 cm.−1 in the type of (Remark: Graphics omitted.). (4) It is shown that the investigation supports the formula with double bonds in the case of α-mono-derivatives of furan.