Manufacture by Acid Treatment

White oils, containing no significant levels of aromatics or sulfur-containing compounds, have no antioxidant capability and will undergo oxidation to peroxides and hydroperoxides readily and at the same time show no visible signs of chemical change. Therefore storage conditions should be maintained at ambient temperatures. Because of this instability, addition of an antioxidant such as butylated hydroxytoluene (BHT) or vitamin E is permitted in some jurisdictions. 

White oils are referred to as naphthenic or paraffinic depending on their crude source. Alternatively it has been suggested that they may be defined by the percent type of carbon atoms, with paraffinic white oils having 50% or more paraffinic carbons and naphthenic oils having at least 40%.8 

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Silica gel. Silica gel is a porous amorphous form of silica (Si02) and is manufactured by acid treatment of sodium silicate solution and then dried. The silica gel surface has an affinity for water and organic material. It is primarily used to dehydrate gases and liquids. 

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