Extraction of neutral oil

Neutral oil or neutral fatty matter is the nonionic fraction of an anionic surfactant. It is the fraction obtained by extraction under such conditions that the anionic itself is not extracted. It contains the unsulphated alcohol or unsulphonated hydrocarbon or other starting material, together with sultones, sulphones and possibly other trace constituents. This is an abbreviated version of the procedure given in section 3.1.2. The sample size may be varied. Other variations include the use of different volumes 

Weigh a 5g sample, dissolve it in 50% ethanol and transfer to a separating funnel with the same solvent. 

Make just alkaline to phenolphthalein with 1 M sodium hydroxide. 

Extract with four 100 ml portions of petroleum ether. 

Combine the petroleum ether extracts and wash with 100 ml of 50% ethanol. 

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