Petrolatum Guide

Petroleum jelly is a flammable, semi-solid mixture of hydrocarbons, having a melting-point usually ranging from a little below to a few degrees above 75°C (167°F). It is colorless, or of a pale yellow color (when not highly distilled), translucent, and devoid of taste and smell when pure. It does not oxidize on exposure to the air, and is not readily acted on by chemical reagents. It is insoluble in water. It is soluble in dichloromethane, chloroform, benzene, diethyl ether, carbon disulfide and oil of turpentine.

There is a common misconception (resulting from the similar feel they produce when applied to human skin) that petroleum jelly and glycerol (glycerine) are physically similar. While petroleum jelly is a non-polar hydrocarbon hydrophobic (water-repelling) and insoluble in water, glycerol (not a hydrocarbon but an alcohol) is the opposite: it is so strongly hydrophilic (water-attracting) that by continuous absorption of moisture from the air, it produces the feeling of wetness on the skin, similar to the greasiness produced by petroleum jelly. The feeling is similar, but petroleum jelly repels water, and glycerine attracts it.

Producers of microcrystalline wax[3] and related materials often produce petrolatums. Some testing standards used by these companies are as follows:...