(N,N')-Bis-hydroxybenzyl urea heavy metal chelates - used as fertilisers supplying trace element and nitrogen (NL 28.12.77)

N,N'-bis-(2-hydroxybenzyl)-urea derivs. of formula (I) and their Fe (II), Fe (III), Cu (II), Zn, Mn (II), Co (II) and Ni (Ii) chelates are new. In the formula, X1 and X2 are same or different -SO3M or -COOM; M is H; alkali metal, alkaline earth metal or mono-, di- or triethylamino; one of X1 and X2 may also be 1-4C opt. branched alkyl). The chelates of (I) are fertiliser components, which supply nitrogen as well as heavy metal trace elements for preventing deficiency diseases (e.g. iron chlorosis). The metal of the chelate is highly utilised and rapidly resorbed in the roots and foliage. The chelates may be used alone (e.g. as 0.5-50% aq. soln.) e.g. urea, superphosphate, K salts, NH4NO3). (I) are intermediates for the chelates. In an example, N, N'-bis-(2-hydroxy-5-SO3K-benzyl)-urea was prepd. from KSO3-pC6H4-OH, HCHO and urea then converted to a chelate with aq. FeCl3. La présente invention a pour objet un procédé de préparation de nouveaux dérivés carbamidiques et de leurs chélates métalliques, répondant à la formule genérale :