Reaction of fatty acids with 3,3′-iminobis-propylamine to produce soil hydrophobic agents

Abstract

The reaction between two moles of fatty acid and one of 3,3′-iminobis-propylamine (DPTA) is somewhat analogous to the reaction between fatty acid and diethylenetriamine (DETA) that we had reported previously, but there are significant differences. Conversion to the diamide HN(CH₂CH₂CH₂NHCOR)₂ proceeds much more rapidly but less efficiently than does the reaction of fatty acid with DETA. The former diamide is obtained in only about a 70% yield and byproducts are obtained, whereas the reaction with DETA yields the diamide almost quantitatively. Cyclization to the pyrimidine

$$RCONHCH_2 CH_2 CH_2 NCH_2 CH_2 CH_2 N = CR$$

is extremely slow and incomplete. The analogous cyclization of α,ω-diamides of DETA produces high yields of imidazolines. The AOCs wet method for amine titration gave erroneous structural information when the test was applied to the diamides of DPTA, as was the case for the DETA-diamide. The water repellency of soils treated with a homologous series of fatty iminobis-propylamine (DPTA)-diamides was studied, and the following observations were made: 1) the fatty DPTA-diamides were slightly more hydrophobic than the fatty DETA-diamides, which we ascribe to the additional methylene groups of the former; 2) hydrophobicity intensified with increasing molecular weight of the saturated fatty acids; and 3) unsaturation, as in the oleic derivative, enhanced hydrophilicity.