Naptha - What is it?

Naphtha's price rise causes anxiety. It signals an inevitable increase in polymer prices. So what is naphtha? Is it a compound? Naphtha is a generic term applied to any one of a wide variety of volatile hydrocarbon mixtures. They are obtained from coal tar or more often from petroleum.

Petroleum naphtha or mineral naphtha is obtained from petroleum as a crude distillate that is lighter than kerosene and has a lower boiling point. It contains a mixture of methane-type hydrocarbons. The distillates with lower boiling points than petroleum naphtha are called ligroin.

Other forms of naphtha are crude naphtha, obtained from coal tar; shale naphtha, obtained from shale; and wood naphtha, obtained from wood.

Solvent naphtha, used for dissolving rubber, is a high-boiling-point fraction distilled from coal tar. Physical properties vary widely depending on the mixture. Initial boiling point may may be as low as 27°C and end points may reach as high as 260°C. Boiling ranges could be as narrow as 11°C or as high as 110°C. In the strictest sense of the term naphtha, not less than 10% of the material should distill below 175°C and not less than 95% should distill below 240°C. Strictly speaking refinery products like gasoline and kerosene are also naphthas.

Naphthas are primarily produced by fractional distillation. Extractive distillation is used when certain high quality naphthas are desired. Acid, clay treating removes sulphur compounds and improves odour and stability. Products sold as naphthas find their use as solvents, thinners, or as carriers. Naphthas could be classified between aliphatic (paraffinic) naphthas and aromatic types. Aliphatic naphthas are relatively low in odor and toxicity and low in solvent power. These are used in processing of soyabeans for oil extraction, by dry cleaners, as a carrier in printing inks. Aromatic naphthas are the high solvency type. The main components are toluene and xylenes. These are used as thinners for paints and varnishes. Rubber industry also uses naphtha as solvents. Leather industry uses them to degrease the skin, metal industry to degrease metals. naphthas also find usage in floor waxes, furniture waxes, shoe polishes and metal polishes. And offcourse naphtha is used in the manufacture of synthetic (artificial) resins. Pure naphtha is highly explosive when exposed to an open flame.