Naphtha ( or ) is a flammable liquid hydrocarbon mixture. Mixtures labelled naphtha have been produced from natural gas condensates, petroleum distillates, and the distillation of coal tar and peat. In different industries and regions naptha may also be crude oil or refined products such as kerosene. Mineral spirits, also historically known as "naptha", are not the same chemical.
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Etymology
The word naphtha is from Latin and Ancient Greek (?????), derived from Middle Persian naft ("wet", "naphtha"), from Old Persian ???. In Ancient Greek, it was used to refer to any sort of petroleum or pitch. The term entered Semitic languages as well in antiquity: It appears in Arabic as ????? naf? ("petroleum"), in Syriac as ?????? naft?, and in Hebrew as ????? neft.
The book of II Maccabees tells how a "thick water" was put on a sacrifice at the time of Nehemiah and when the sun shone it caught fire. It adds that "those around Nehemiah termed this 'Nephthar', which means Purification, but it is called Nephthaei by the many [literally hoi polloi]."
Naphtha is the root of the word naphthalene. The second syllable of "naphtha" can also be recognised in phthalate.
It also enters the word napalm, a contraction of the "na" of naphthenic acid and "palm" of palmitic acid, originally made from a mixture of naphthenic acid combined with aluminium and magnesium salts of palmitic acid.
In older usage, "naphtha" simply meant crude oil, but this usage is now obsolete in English. It was also used for mineral spirits (also known as "Stoddard Solvent"), the "naptha" originally in Fels Naptha laundry soap. The Ukrainian and Belarusian word ????? (lit. nafta), Lithuanian, Latvian and Estonian "nafta", the Russian word ????? (lit. neft') and the Persian naft (???) mean "crude oil". Also, in Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Italy, Serbia, Slovenia, nafta (????? in Cyrillic) is colloquially used to indicate diesel fuel and crude oil. In the Czech Republic and Slovakia, nafta was historically used for both diesel fuel and crude oil, but its use for crude oil is now obsolete and it generally indicates diesel fuel. In Bulgarian, nafta means diesel fuel, while neft, as well as petrol (?????? in Cyrillic), means crude oil. Nafta is also used in Argentina, Paraguay and Uruguay to refer to gasoline/petrol. In Poland, the word nafta means kerosene. In Flemish, the word naft is used colloquially for gasoline.
There is a conjecture that the Greek word naphtha came from the Indo-Iranian god name Apam Napat, which occurs in Vedic and in Avestic; the name means "grandson of (the) waters", and the Vedas describe him as fire emerging from water, perhaps inspired by a burning seepage of natural gas.
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Types
Various qualifiers have been added to the term "naphtha" by different sources in an effort to make it more specific:
One source distinguishes by boiling point:
Light naphtha is the fraction boiling between 30 °C and 90 °C and consists of molecules with 5-6 carbon atoms. Heavy naphtha boils between 90 °C and 200 °C and consists of molecules with 6-12 carbon atoms.
Another source differentiates light and heavy comments on the hydrocarbon structure, but offers a less precise dividing line:
Light [is] a mixture consisting mainly of straight-chained and cyclic aliphatic hydrocarbons having from five to nine carbon atoms per molecule. Heavy [is] a mixture consisting mainly of straight-chained and cyclic aliphatic hydrocarbons having from seven to nine carbon atoms per molecule.
Both of these are useful definitions, but they are incompatible with one another. These terms are also sufficiently broad that they are not widely useful.
Health and safety considerations
The material safety data sheets (MSDSs) from various naphtha vendors are also indicative of the non-specific nature of the product and reflect the considerations due for a flammable mixture of hydrocarbons: flammability, carcinogenicity, skin and airway irritation, etc.
Humans can be exposed to naphtha in the workplace by breathing it in, swallowing it, skin contact, and eye contact. The US Occupational Safety and Health Administration (OSHA) has set the permissible exposure limit for naphtha exposure in the workplace as 100 ppm (400 mg/m3) over an 8-hour workday. The US National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 100 ppm (400 mg/m3) over an 8-hour workday. At levels of 1000 ppm, 10% of the lower explosive limit, naphtha is immediately dangerous to life and health.
Source of the article : Wikipedia
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