Naphtha
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2008-07-15T20:34:01Z
Tim Q. Wells
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'''Naphtha''' normally refers to a number of different flammable liquid mixtures of hydrocarbons, i.e. a distillation product from [[petroleum]] or [[coal tar]] boiling in a certain range and containing certain hydrocarbons, a broad term encompassing any volatile, flammable liquid hydrocarbon mixture.
Naphtha is used primarily as feedstock for producing a [[ Octane rating|high octane]] [[gasoline]] component (via the [[catalytic reforming]] process). It is also used in the [[petrochemical]] industry for producing [[olefin]]s in [[steam crackers]] and in the chemical industry for [[solvent]] (cleaning) applications.
==Etymology==
The origin of the word '''Naphtha''' is unclear. It is an Ancient Greek word that was used to refer to any sort of [[petroleum]] or [[Pitch (resin)|pitch]]. The Greeks themselves borrowed the word from the [[Old Persian]] words ''nafata'', ''naft'' or ''neft'', which were used to describe bubbling oil. Naphtha may also have been derived from the name of the [[Veda|Vedic]] [[Hindu]] and [[Avesta|Avestic]] god [[Apam Napat]], a form of [[Agni]], or fire god.
Naphtha is the root of the words [[naphthalene]] and [[napalm]], which is derived from naphtha by mixing under controlled conditions with aluminium salts of palmitic acid (a type of soap).
In older usage, naphtha simply meant [[crude oil]], but this usage is now obscure.
==Health and safety considerations==
Forms of naphtha may be [[carcinogen]]ic, and frequently products sold as naphtha contain some impurities, which may also have deleterious properties of their own. [http://nafaa.pbwiki.com/Naphtha] [http://monographs.iarc.fr/ENG/Monographs/vol47/volume47.pdf] Like many [[hydrocarbon]] products, because they are products of a [[refractory]] process where a complex soup of chemicals is broken into another range of chemicals, which are then graded and isolated mainly by their [[specific gravity]] and [[Volatility (chemistry)|volatility]], there is a range of distinct chemicals included in each product. This makes rigorous comparisons and identification of specific carcinogens difficult, especially in our modern environment where exposure to a great number of such products occurs on a daily basis, and is further complicated by exposure to a significant range of other known and potential carcinogens (e.g., see [http://www.defence.gov.au/dpe/dhs/research/shoamp/Mortality_Final_report_Sept_2003.pdf]).
Below are linked some Material Safety Data Sheet (MSDS) specifications for different "naphtha" products, which contain varying degrees of naphtha, as well as various other chemicals. As well as giving health guidelines, these are some of the few ways to determine what a given product contains.
* JT Baker VM&P Naphtha [http://www.jtbaker.com/msds/englishhtml/p1696.htm MSDS].
* Diggers Shellite [http://www.diggersaust.com.au/files/Shellite.pdf MSDS]
* Shell Ronsonol MSDS [http://www.cooperbooth.com/datasheets/160606.pdf source1] [http://pages.slc.edu/~aschultz/chemical_hygiene/MSDS/theater%20msds/LIGHTER%20FLUID.PDF source2]
* Links to [http://www.nafaa.org/msds.html more MSDS] for various camping-stove fuels including several that include naphtha
[[Benzene]] in particular is a known high-risk carcinogen, and so benzene content is typically specified in the MSDS. But more specific breakdown of particular forms of hydrocarbon is not as common.
==Properties of naphthas==
===Physical properties===
Molecular weight range is 100-215 g/mol; specific gravity range is 0.75-0.85 g/cm<sup>3</sup>; boiling point range is 320-430°F; vapor pressure is < 5 mm Hg (< 5 torr). Naphthas are insoluble in water; colorless (kerosene odor) or red-brown (aromatic odor) liquid; incompatible with strong oxidizers.
==Production of naphtha in refineries==
Naphtha is obtained in [[petroleum]] refineries as one of the intermediate products from the [[Continuous distillation#continuous fractional distillation of crude oil|distillation of crude oil]]. It is a liquid intermediate between the light gases in the crude oil and the heavier liquid [[kerosene]]. Naphthas are volatile, flammable and have a [[specific gravity]] of about 0.7. The generic name naphtha describes a range of different refinery intermediate products used in different applications. To further complicate the matter, similar naphtha types are often referred to by different names.
The different naphthas are distinguished by:
* density (g/ml or specific gravity)
* PONA, PIONA or PIANO analysis, which measures (usually in volume percent but can also be in weight percent):
** [[Paraffin]] content (volume percent)
** [[Isoparaffin]] content (only in a PIONA analysis)
** [[Olefin]]s content (volume percent)
** [[Naphthene]]s content (volume percent)
** [[Aromatic]]s content (volume percent)
==Different types of naphthas==
=== Paraffinic naphthas===
Generally speaking, less dense ("lighter") naphthas will have a higher [[paraffin]] content. These are therefore also referred to as '''paraffinic naphtha'''. The main application for these naphthas is as a feedstock in the petrochemical production of [[olefin]]s. This is also the reason they are sometimes referred to as "light distillate feedstock" or '''LDF''' (these naphtha types can also be called "straight run gasoline"/'''SRG''' or "light virgin naphtha"/'''LVN''').
When used as feedstock in petrochemical steam crackers, the naphtha is heated in the presence of water vapour and the absence of oxygen or air until the hydrocarbon molecules fall apart. The primary products of the cracking process are olefins ([[ethylene]] / [[ethene]], [[propylene]] / [[propene]] and [[butadiene]]) and aromatics ([[benzene]] and [[toluene]]). These are used as feedstocks for derivative units that produce [[plastic]]s ([[polyethylene]] and [[polypropylene]] for example), [[synthetic fiber]] precursors ([[acrylonitrile]]), industrial chemicals ([[glycol]]s for instance).
===Heavy naphthas===
[[Image:Camp fuel.jpg|thumb|300px|right|Coleman Camp Fuel, also known as white gas, is a common naphtha fuel used in many lanterns and torches]]
The "heavier" or rather denser types are usually richer in naphthenes and aromatics and therefore also referred to as N&A's. These can also be used in the petrochemical industry but more often are used as a feedstock for refinery catalytic reformers where they convert the lower [[octane rating|octane]] naphtha to a higher octane product called [[reformate]]. Alternative names for these types are Straight Run Benzene (SRB) or Heavy Virgin Naphtha (HVN).
==Other applications / descriptions==
Naphthas are also used in other applications such as:
* (as an unprocessed component - in contrast to reforming above) in the production of [[petrol]]/[[gasoline|motor gasoline]].
* industrial [[solvents]] and cleaning fluids
* an oil painting medium
* the sole ingredient in the home cleaning fluid Energine, which has been discontinued.
* an ingredient in [[shoe polish]]
* an ingredient in some lighter fluids for wick type [[lighter]]s such as [[Zippo]] lighters.
* an [[adulterant]] to petrol
* a fuel for [[portable stove]]s and [[lantern]]s, sold in North America as '''white gas''' or '''[[Coleman Company|Coleman]] fuel'''.
* historically, as a probable ingredient in [[Greek fire]] (together with grease, oil, sulfur, and naturally occurring [[Sodium nitrate|saltpeter]] from the [[desert]])
* a fuel for [[fire spinning]], fire [[juggling]], or other fire performance equipment which creates a brighter and cleaner yet shorter burn.
* to lightly wear the finish (polish) off [[guitar]]s when preparing "relic" instruments.
* to remove oil from the [[diaphragm (optics)|aperture blades]] of [[Photographic lens|camera lenses]], which if present can slow the movement of the blades, leading to [[Exposure (photography)|overexposure]].
* in medieval times, pots containing naphtha were used in battle as a form of primitive grenade.
* Naptha is used in the furniture industry on "works in progress" to artificially, and temporarily (until it evaporates) see what the patina will look like when the piece is oiled and/or aged. It is useful in matching adjacent boards for a join, primarily with tabletops, panels and shelves.
* in the process of extracting pure [[Dextromethorphan]] from cough syrup
* fuel in torches used by torch jugglers
==Health hazards==
“Light naphtha, a mixture consisting mainly of straight-chained and cyclic aliphatic hydrocarbons having from five to nine carbon atoms per molecule. Heavy naphtha, a mixture consisting mainly of straight-chained and cyclic aliphatic hydrocarbons having from seven to nine carbons per molecule.”<ref>“Chemistry of Hazardous Materials, Third Edition”, Meyer, E., Prentice Hall, 1998, page 458.</ref> “Almost all volatile, lipid-soluble organic chemicals cause general, nonspecific depression of the central nervous system or general anesthesia.” <ref>“Occupational and Environmental Medicine, Third Edition”, LaDou, J. , MS., MD. Lange Medical Books, McGraw Hill, 2004, page 508.</ref> The OSHA PEL TWA = 100 parts-per-million (ppm); Health Hazards/Target Organs = eyes, skin, RS, CNS, liver kidney. Symptoms of acute exposure are dizziness and narcosis with loss of consciousness. The [[World Health Organization]] categorizes health effects into three groups: reversible symptoms (Type 1), mild chronic encephalopathy (Type 2) and severe chronic toxic encephalopathy (Type 3).
==Examples in daily life==
''Shellite'' ([[Australia]]), also known as ''white gas'' ([[North America]]), ''white spirit'' or ''[[Coleman Company|Coleman]] fuel'', is a water white liquid with a hydrocarbon odour. Shellite has a [[freeze point]] less than {{convert|-30|C|0}}, and a [[boiling point]] of {{convert|47|C}}. The composition of shellite is 95% [[paraffin]]s and naphthenes, less than 5% aromatic hydrocarbons and less than 0.5% [[benzene]]. It is highly flammable and due to its low [[flashpoint]] is used in many low pressure camping stoves. Shellite is also a fast drying solvent used for cleaning metal, hard plastic and painted surfaces.
''Ronsonol'' is a brand name used in North America, and is marketed principally as a refill fluid for [[cigarette lighter]]s and has a flashpoint of about {{convert|6|C}}.
==References==
{{reflist}}
==See also==
* [[Petroleum]]
* [[Naphthalene]]
* [[Olefin]]
* [[Oil refinery]]
* [[Benzene]]
* [[n-Hexane]]
* [[Fluid catalytic cracking]]
==External links==
* [http://www.cdc.gov/niosh/npg/ NIOSH Pocket Guide to Chemical Hazards] from the US [[National Institute for Occupational Safety and Health]]
* [http://www.chemicalforums.com/index.php?page=searchmsds Search a number of sites for MSDS]
* [http://members.iinet.net.au/~mbuckler/fuel/index.shtml#whitespiritgas Different names with different meanings in different countries, for some naphtha-containing camping-stove products]
* [http://www.santos.com/Content.aspx?p=167 Cooper Basin naphtha] manufacturer's description
* [http://siri.org/msds/man/man.html Lists of many chemical manufacturer's MSDS sites]
* [http://ptcl.chem.ox.ac.uk/MSDS/ The Physical and Theoretical Chemistry Laboratory Oxford University Chemical and Other Safety Information]
*[http://toxnet.nlm.nih.gov/cgi-bin/sis/search/r?dbs+hsdb:@term+@na+naphtha NLM Hazardous Substances Databank – Naphtha]
==Additional Sources==
*McDermott, Henry J. (2004). Air Monitoring for Toxic Exposures (Second Edition) John Wiley & Sons, Inc.
[[Category:Petroleum products]]
[[Category:Oil refineries]]
[[Category:Chemical engineering]]
[[Category:Hydrocarbon solvents]]
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