Imidazolines are made commercially from the reaction of fatty acid, fatty methyl esters, or fatty triglycerides with a polyamine such as diethylenetriamine (~), aminoethylethanolamine (~), ethylenediamine
(~), or triethylenetetramine (~). (There are very few examples of the use of shorter-chain carboxylic acids or in one case, formamide. )
There has not been general agreement about the exact structure of the intermediate diamide. Without experimental evidence, Dobozy  concluded that the intermediate was aI, 2-, not aI, 3-diamide (the numbers 1, 2, and 3 refer to the N atoms in the DETA). However, later work by Butler and O'Regan  showed that the 1,3diamide was the product of the reaction of 2 mol of fatty acid with DETA. Confirmation of the 1,3 arrangement was made by infrared (IR), IH nuclear magnetic resonance (NMR), and 13C NMR. Still other authors  followed the rate of reaction of 2 mol of tallow fatty acids and 1 mol of DETA using analyses for free fatty acid and primary, secondary, and tertiary amine. Their analyses showed that when essentially all the fatty acid had been consumed, the primary amine value reached a constant value consistent with one free primary amino group. Thus they claim that the 1, 2-diamide structure is the true intermediate. This is not the whole story, however.