Chemical structure of liquid paraffin
Liquid paraffin, used commonly in medical and industrial applications, consists of a mixture of hydrocarbon chains rather than a single type of molecule. It also goes by the names mineral oil and paraffin oil.
According to a 1972 "Chemistry and Technology of Fuels and Oils" article, mineral oil, or liquid paraffin, consists of a mixture of alkanes. This term refers to a subgroup of hydrocarbons. Alkanes consist solely of single-bonded carbon and hydrogen atoms. Some alkanes in liquid paraffin have a straight chain shape; others have more than one branch in their molecular structure, making them isoalkanes.
Liquid paraffin burns easily and serves as a lamp oil, the Artists Resource for Fire website states. Drugstores sell mineral oil over the counter as a laxative; the same variety makes a good medium for preparing samples in infrared spectroscopy, according to 2004 articles in the "Internet Journal of Vibrational Spectroscopy."
Molecular Size Effects
The alkanes' large molecular size makes liquid paraffin less volatile than other alkane mixtures such as gasoline, according to a Brigham Young University website information on vapour-liquid equilibria. Therefore, paraffin oil has little odour because the particles do not evaporate easily.