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Atomic weight of germanium
Sept., I92I,]
EASTMAN KODAK COMPANY NOTES.
ELECTROLYTIC
MANUFACTURE
387
OF p-AMINOPHENOL2
By A. S. McDaniel, L. Schneider, and A. Ballard.
[a~STRACr.] NITROBENZENE was reduced electrolytically at 3 °o C. in strong sulphuric acid (90-91 per cent.), free from iron and heavy metals, using platinum electrodes, with a cathode current density of 6-8 amperes per IOO square centimetres, and anode density double. Glazed earthenware cells with porus diaphragms of thin, dense porcelain were used. Under these conditions minimum sulphonation was obtained. By washing the cell sludge with commercial hydrochloric acid, centrifuging, and treating with pure hydrochloric acid p-aminophenol hydrochloride was obtained, the yield being 4o-5o per cent. on the nitrobenzene (exclusive of mother liquors which yield a further IO per cent.). Apart from the cost of platinum, the most important economic factor is the necessity of providing for the cheap concentration of the spent acid. Cost of upkeep, owing to the excessive corrosive action of the matrials on the apparatus, is also considerable.
Atomic Weight of Germanium.--(Correction.) John H. Mflller of the University of Pennsylvania has determined the atomic weight of germanium by heating a known mass o,f potassium fluogermanate in a current of hydrogen chloride, and weighing the residual potassium chloride (Jour. A m . Chem. Soc., ~92I, xliii, Io85Jo95). Seven determinations gave, as an average, an atomic weight of 72.4~8 for germanium. J.S.H. Prof. C. Runge, of Goettingen, has sent to N a t u r e a list of men of science in Germany who have died since the beginning of the war. Among them are: Physicists--I-Iittorf, Riecke, E. Mach, Helmert, W. Voigt and Elster; chemists--E. Fischer and A. yon Baeyer; mathematicians--Lexis, R. Dedekind, Frobenius, Cantor, Staeckel, Thomae and T. Reye; astronomers--yon Auwers, Schwarzschild, Bruns, and W. Foerster; botanists--Voechting, Solms-Laubach, W. Pfeffer, whose investigations led to the conception of osmotic pressure, and Schwendener. G.F.S. 3 Trans. Amer. Electrochem. Soc., 192I, p. 319-327, Communication No. 69, from the :Research Laboratory of the Eastman Kodak Company
EASTMAN KODAK COMPANY NOTES.
ELECTROLYTIC
MANUFACTURE
387
OF p-AMINOPHENOL2
By A. S. McDaniel, L. Schneider, and A. Ballard.
[a~STRACr.] NITROBENZENE was reduced electrolytically at 3 °o C. in strong sulphuric acid (90-91 per cent.), free from iron and heavy metals, using platinum electrodes, with a cathode current density of 6-8 amperes per IOO square centimetres, and anode density double. Glazed earthenware cells with porus diaphragms of thin, dense porcelain were used. Under these conditions minimum sulphonation was obtained. By washing the cell sludge with commercial hydrochloric acid, centrifuging, and treating with pure hydrochloric acid p-aminophenol hydrochloride was obtained, the yield being 4o-5o per cent. on the nitrobenzene (exclusive of mother liquors which yield a further IO per cent.). Apart from the cost of platinum, the most important economic factor is the necessity of providing for the cheap concentration of the spent acid. Cost of upkeep, owing to the excessive corrosive action of the matrials on the apparatus, is also considerable.
Atomic Weight of Germanium.--(Correction.) John H. Mflller of the University of Pennsylvania has determined the atomic weight of germanium by heating a known mass o,f potassium fluogermanate in a current of hydrogen chloride, and weighing the residual potassium chloride (Jour. A m . Chem. Soc., ~92I, xliii, Io85Jo95). Seven determinations gave, as an average, an atomic weight of 72.4~8 for germanium. J.S.H. Prof. C. Runge, of Goettingen, has sent to N a t u r e a list of men of science in Germany who have died since the beginning of the war. Among them are: Physicists--I-Iittorf, Riecke, E. Mach, Helmert, W. Voigt and Elster; chemists--E. Fischer and A. yon Baeyer; mathematicians--Lexis, R. Dedekind, Frobenius, Cantor, Staeckel, Thomae and T. Reye; astronomers--yon Auwers, Schwarzschild, Bruns, and W. Foerster; botanists--Voechting, Solms-Laubach, W. Pfeffer, whose investigations led to the conception of osmotic pressure, and Schwendener. G.F.S. 3 Trans. Amer. Electrochem. Soc., 192I, p. 319-327, Communication No. 69, from the :Research Laboratory of the Eastman Kodak Company