diethylamine in tetrachloromethane byproducts: N,N'-diphenylurea, CO2; refluxing (10 h); cooling, filtration off diphenylurea, cooling in ice, Et2NH addn., filtration, washing of ppt. (pentane), evapn. (reduced pressure), filtration, distn. (vac.);

aluminum oxide in pentamethylene 223°C/normal pressure, mixture of the dienes (ratio germanole : methylene-compd. 17 : 83) is obtained;

aluminum oxide in gas byproducts: H2O; catalytic dehydration on Al2O3 in gas phase (reduced pressure 0.01 mmHg, 300°C); condensation into cold trap; detn. by (1)H-NMR spectroscopy;