EFFECT OF STRUCTURE ON NITRIFICATION OF UREA DERIVATIVES

Reaction of urea with formaldehyde gives the commercial ureaforms; reaction with higher aldehydes gives products which release nitrogen more rapidly and completely than ureaforms due to their lower molecular weight and their susceptibility to hydrolysis by soil moisture. A series of symmetrical dialkylmethylenediureas has been prepared for comparison as controlled release nitrogen fertilizers. As the alkyl substituents were varied from C1 to C4, the solubility and rate of nitrification both decreased. Nitrogen release was relatively complete and uniform. Time for complete release varied from 12 to 15 weeks for the dimethyl and diethyl compounds to about one year for diisopropylmethylenediurea. The observed effects on nitrification were not due merely to substitution on terminal urea groups, since the corresponding 1,3-dialkylureas, with the exception of the dimethyl compound, were resistant to nitrification and exerted an inhibiting effect. © 1969, American Chemical Society. All rights reserved.