The electrolysis of organic compounds : Papers / by Hermann Kolbe (1845-1868).

  • Kolbe, Hermann, 1818-1884.
Date:
1900
Catalogue details

Licence: In copyright

Credit: The electrolysis of organic compounds : Papers / by Hermann Kolbe (1845-1868). Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    as electrodes. The decomposition proceeds quietly and without evolution of gas at first, with a somewhat con- siderable elevation of temperature. Only after a large part of the sesquichloro-carbohyposulphuric acid is con- verted into methyl hyposulphuric acid does hydrogen become free at the cathode. This circumstance can be made use of in order to determine at any time, approxi- mately at least, how much chlorine has been exchanged for hydrogen. According to the formula : it is calculated that 57 grms. of zinc are necessary for the conversion of 70 grms. of sesquichloro-carbohyposulphate of potash. The deflection of the magnetic needle of a AVeber's tangent galvanometer introduced into the circuit, amounted in these experiments, on the average, to be- tween 50° and 60°, which corresponds, in the case of the instrument employed, to an average strength of current of about 82. Since with this strength of current, about 10 grms. of zinc are dissolved in an hour, the above decomposition would be finished in 6 hours. After the action of the current for one hour, the liquid was so saturated with chloride of zinc that metallic zinc was deposited upon the cathode in large quantity. It was therefore precipitated, boiling, with carbonate of potash; the filtered alkaline solution was evaporated to the original volume and exposed anew to the action of the current for an hour, until the quantity of the separated carbonate of zinc had increased so greatly that reduction upon the cathode ensued. It was only after 45 grms. of zinc, from the anode, were dissolved, in the course of repeated operations, that a ko f c.,eas.,o5 6Zn 6HO ( KO + C.te3S.iOr, < 6ZnO