I am currently doing imidazoline synthesis. I react between oleic acid and Diethylenetriamine with a temperature condition of 170 for 12 hours for the amidation reaction, and cyclize at 230 for 16 hours. Both of these temperatures I use vacuum.

But, when at 170 the value of amine decreases drastically, when it should not decrease significantly, right? Then the second method I did was non-vacuum at 170 and vacuum at 230, but finally when I checked at the initial 230 the amine value also decreased significantly.

Is there any input or advice to maintain the amine value of my imidazoline. I hope my imidazoline is a brown liquid and there is no precipitation or stable as a liquid at room temperature

Oh yes, my reaction is without using solvents. so only on oleic acid and its DETA only