Diethanolamine
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I would like to ask an experienced colleague for advice. Today I conducted an experiment: at room temperature (18 degrees), diethanolamine was dissolved using an alkaline solution, which resulted in the formation of a solid. When the temperature was increased, the substance dissolved again; then it was added to light oil, and white solids were formed once more, which ended up in the oil phase. Even when the temperature was raised to 30–40 degrees, the substance did not dissolve. I’m not sure what the reason for this is.
The white solid is an organic salt; it has a high distribution coefficient in the oil phase, so it moves into that phase. However, its solubility is low, which is why it does not dissolve when the temperature is increased.
A very fundamental principle in chemistry: like dissolves like. Ethanolamine and bases (the ones you mentioned are likely inorganic bases) are both polar compounds. But their polarity strengths vary. Light oils are non-polar liquids; they can only dissolve non-polar and weakly polar substances. The white solid that was released again, as you mentioned, should be an inorganic base.
Like dissolves like, it would be helpful to take samples for analysis if possible
It is recommended to heat the temperature to 80 degrees, at which point it should dissolve; however, a flocculent substance will be formed during the dissolution process.