Whole cut fatty acids

The removal of contaminants (unreacted triglycerides, odor and color bodies, polymerized matter, and decomposition products) from split fatty acids is achieved by simple distillation.17a,b The products obtained from such straight distillations are called whole cut fatty acids (e.g., whole coconut fatty acid). 

For personal care applications, the major products in this group are amphoacetates or amphodiacetates , generally based on alkyl hydroxyethyl imidazolines from either a whole coconut fatty acid distribution or a lauric cut. The ampho portion of their name is a convention established by the International Nomenclature Committee for Cosmetic Products (INCI) to indicate that they are derived from imidazoline structures. The INCI nomenclature applied to these materials, amphoacetate and amphodiacetate, is intended to give an indication of the stoichiometry used to produce them, either 1 or 2 mol of sodium chloroacetate is added to each mole of fatty imidazoline. Modern analytical methods have been used to determine the structure of these products and almost all of them are actually monoacetates . The main difference between amphoacetates and ampho diacetates is the composition of the by-products. 

Fractionation makes it possible to separate the fatty acid mixtures into narrower cuts or even individual components. The detergent-grade feedstock C12-C18 fraction is separated from the whole cut by topping off the C8-C10 fraction. The middle cut, C12-C14, can be further fractionated from the C12-C18 cut through the use of multistage fractionation employing two or more columns. 

Cocamidopropyldimethyl amine can be prepared from whole coconut oil, coconut fatty acid, or methyl esters either whole cut or stripped of the C6-C10 chain fractions. The aforementioned tertiary amines are converted to betaines by reaction with sodium monochloroacetate (SMCA) in a relatively dilute aqueous system (Scheme 1.1). 

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