This double reaction is carried at a low cost, but precaution is required to control the
conditions and avoid side reactions. Sulfated monoglycerides which are neutralized by an
ethanolamine are excellent foaming agents, even with a C18 chain. This is remarkable since
alkyl-sulfates are foaming agents only with short C12-C14 chain, i.e., a lipophilic group which
comes from coconut oil, and thus a raw material much more expensive than tallow (C16-C18).
A mole of sulfuric acid can be added on a double bond of one of the acid of a glyceride.
The sulfated acid can be separated (by hydrolysis) or stay in the glyceride, to result in an
emulsifying agent.
The sulfate of ricinoleic acid (12-hydroxy-9-octadecenoic acid) which comes from castor
oil is used as a fixer of Turkey red dye (alizarine) on wool. Turkey red oil, a mixture of sulfated
castor oil compounds, was one of the first attempt (in 1875) to produce a soap with some
insensitivity to calcium ions.