Studies on the Carbon and nitrogen cycles in the Soil. IV. Natural and artificial humic acids

The preparation of natural humic acids from soil, peat (Dopplerite) and “Adco,” and of artificial “humic” acids from sucrose, cellulose, dextrose and glycine (Maillard), furfural, hydroquinone and lignin, and their purification is described. Their elementary composition and their behaviour under conductometric titration with ammonia have been studied. The artificial products from sucrose and furfural did not behave as acids, but all the natural products, and the artificial products from cellulose, hydroquinone and lignin possessed the properties of colloidal acids. Preliminary investigations into the “humification” of furfural and ω-hydroxymethyl furfural, and into the interaction of dextrose with amino bodies, are described.