NAPHTHA. The word naphtha is derived from the oriental term nafata, signifying to ooze out, and was originally applied to a yellowish white, volatile, inflammable, liquid hydrocarbon, which exudes from the soil in certain parts of Persia, Italy, &c. The very fluid portions of those natural tar-like matters [ASPHALT; BITUMEN; PETROLEUM] that issue from the ground in so many parts of the world, having been found to be almost identical with the original nafata, have been in cluded under the term naphtha, and the latter word is therefore, or rather should be, now used to designate any light, more or less colour less, inflammable fluid, of mineral origin and immiscible with water. Naphtha is sometimes specifically termed mineral naphtha.
Other liquids, resembling true naphtha in little else than the cha racters of volatility and inflammability, have also been called naphtha. Thus wood-spirit has frequently been so named, and is still often spoken of as wood-naphtha ; see METHYL, hydrated oxide of. ACETONE is also sometimes described under the name of naphtha. Lastly, COAL TAR yields by distillation a liquid having all the characters of natural naphtha ; it is, however, generally distinguished as coal naphtha.
The origin of naphtha is, in all probability, due to the action of internal heat upon beds of coal or peat, these substances being, in nearly all cases, found in the neighbourhood of the petroleum or naphtha springs; moreover, the artificial production of coal naphtha, as just described, gives considerable support to this theory.
Crude naphtha is usually contaminated with much colouring matter, but from this it may be freed by rectification. When quite pure it contains no oxygen, and hence is usually the liquid in which potassium, sodium, and other metals that have intense affinity for oxygen are preserved. For the latter purpose it must be several times well
agitated with about a fifth of its bulk of strong sulphuric acid, then washed with water, and finally distilled from quicklime.
Pure naphtha is colourless, and of peculiar taste and odour. It is insoluble in water ; soluble in about eight parts of alcohol ; and mis cible in all proportions with ether, and with the essential oils. With the aid of heat it dissolves one-fourteenth of its weight of phospho rus, or one-twelfth of sulphur, but deposits them on cooling. It dissolves one-eighth of its weight of iodine, absorbs anumoniacal and hydrochloric acid gases, is attacked by chlorine and bromine, and de composed by hot concentrated nitric or sulphuric acids. It is an excellent solvent for gutty pereha, india-rubber, camphor, and oily or resinous bodies generally ; is indeed largely used for these purposes, but chiefly in lamps as a source of artificial light. Its specific gravity varies from to 0'85.
Naphtha seems to be a mixture of several polymeric hydrocarbons. Pelletier and Walter have extracted, and described three, namely, naphtha (CJI„), boiling point 190° ; naplethene (C„H„), boiling point 239'; and naphthote (C„H„), boiling point 374°.
Great care should be observed in manipulating with the more vola tile descriptions of naphtha. It is exceedingly inflammable, and fatal accidents have arisen from its vapour catching fire on the approach of a naked flame.
For the chief localities of the naphtha springs, and statistics con cerning their products, see NAPHTHA, in NAT. HIST. DIV".