Propane

Propane (/ˈproʊpeɪn/) is a three-carbon alkane with the molecular formula C3H8. It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel. Propane is one of a group of liquefied petroleum gases (LP gases). The others include butane, propylene, butadiene, butylene, isobutylene, and mixtures thereof.

Propane
Skeletal formula of propane
Skeletal formula of propane with all implicit carbons shown, and all explicit hydrogens added
Ball and stick model of propane
Spacefill model of propane
Names
Preferred IUPAC name
Propane[1]
Systematic IUPAC name
Tricarbane (never recommended[1])
Identifiers
3D model (JSmol)
1730718
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.000.753
EC Number 200-827-9
E number E944 (glazing agents, ...)
25044
KEGG
RTECS number TX2275000
UNII
UN number 1978
Properties[2]
C3H8
Molar mass 44.097 g·mol−1
Appearance Colorless gas
Odor Odorless
Density 2.0098 kg/m3 (at 0 °C, 101.3 kPa)
Melting point −187.7 °C; −305.8 °F; 85.5 K
Boiling point −42.25 to −42.04 °C; −44.05 to −43.67 °F; 230.90 to 231.11 K
47mgL−1 (at 0 °C)
log P 2.236
Vapor pressure 853.16 kPa (at 21.1 °C (70.0 °F))
15 nmol Pa−1 kg−1
Conjugate acid Propanium
-40.5·10−6 cm3/mol
Thermochemistry
73.60 J K−1 mol−1
−105.2–−104.2 kJ mol−1
−2.2197–−2.2187 MJ mol−1
Hazards
Safety data sheet See: data page
GHS pictograms GHS02: Flammable
GHS signal word DANGER
H220
P210
NFPA 704
Flash point −104 °C (−155 °F; 169 K)
470 °C (878 °F; 743 K)
Explosive limits 2.37–9.5%
US health exposure limits (NIOSH):
PEL (Permissible)
TWA 1000 ppm (1800 mg/m3)[3]
REL (Recommended)
TWA 1000 ppm (1800 mg/m3)[3]
IDLH (Immediate danger)
2100 ppm[3]
Related compounds
Related alkanes
Related compounds
Diiodohydroxypropane
Supplementary data page
Refractive index (n),
Dielectric constantr), etc.
Thermodynamic
data
Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

History

Propane was discovered by the French chemist Marcellin Berthelot in 1857.[5] It was found dissolved in Pennsylvanian light crude oil by Edmund Ronalds in 1864.[6][7] Walter O. Snelling of the U.S. Bureau of Mines highlighted it as a volatile component in gasoline in 1910, which was the beginning of the propane industry in the United States. The volatility of these lighter hydrocarbons caused them to be known as "wild" because of the high vapor pressures of unrefined gasoline. On March 31, 1912, The New York Times reported on Snelling's work with liquefied gas, saying "a steel bottle will carry enough gas to light an ordinary home for three weeks".[8]

It was during this time that Snelling, in cooperation with Frank P. Peterson, Chester Kerr, and Arthur Kerr, created ways to liquefy the LP gases during the refining of gasoline. Together, they established American Gasol Co., the first commercial marketer of propane. Snelling had produced relatively pure propane by 1911, and on March 25, 1913, his method of processing and producing LP gases was issued patent #1,056,845.[9] A separate method of producing LP gas through compression was created by Frank Peterson and its patent granted on July 2, 1912.[10]

The 1920s saw increased production of LP gas, with the first year of recorded production totaling 223,000 US gallons (840 m3) in 1922. In 1927, annual marketed LP gas production reached 1 million US gallons (3,800 m3), and by 1935, the annual sales of LP gas had reached 56 million US gallons (210,000 m3). Major industry developments in the 1930s included the introduction of railroad tank car transport, gas odorization, and the construction of local bottle-filling plants. The year 1945 marked the first year that annual LP gas sales reached a billion gallons. By 1947, 62% of all U.S. homes had been equipped with either natural gas or propane for cooking.[9]

In 1950, 1,000 propane-fueled buses were ordered by the Chicago Transit Authority, and by 1958, sales in the U.S. had reached 7 billion US gallons (26,000,000 m3) annually. In 2004, it was reported to be a growing $8-billion to $10-billion industry with over 15 billion US gallons (57,000,000 m3) of propane being used annually in the U.S.[11]

The "prop-" root found in "propane" and names of other compounds with three-carbon chains was derived from "propionic acid",[12] which in turn was named after the Greek words protos (meaning first) and pion (fat).

Sources

Propane is produced as a by-product of two other processes, natural gas processing and petroleum refining. The processing of natural gas involves removal of butane, propane, and large amounts of ethane from the raw gas, in order to prevent condensation of these volatiles in natural gas pipelines. Additionally, oil refineries produce some propane as a by-product of cracking petroleum into gasoline or heating oil.

The supply of propane cannot easily be adjusted to meet increased demand, because of the by-product nature of propane production. About 90% of U.S. propane is domestically produced.[13] The United States imports about 10% of the propane consumed each year, with about 70% of that coming from Canada via pipeline and rail. The remaining 30% of imported propane comes to the United States from other sources via ocean transport.

After it is separated from the crude oil, North American propane is stored in huge salt caverns. Examples of these are Fort Saskatchewan, Alberta; Mont Belvieu, Texas; and Conway, Kansas. These salt caverns were hollowed out in the 1940s,[14] and they can store 80,000,000 barrels (13,000,000 m3) or more of propane. When the propane is needed, much of it is shipped by pipelines to other areas of the United States. The North American standard grade of automotive use propane is rated HD 5. HD 5 grade has a maximum of 5 percent butane, but propane sold in Europe, has a max allowable amount of butane of 30 percent, meaning it's not the same fuel as HD 5. The LPG used as auto fuel and cooking gas in Asia and Australia, also has a very high content of butane. Propane is also shipped by truck, ship, barge, and railway to many U.S. areas.[15]

Propane can also be produced as a biofuel.[16] Biopropane is commercially sold in Europe.[17]

Properties and reactions

Propane flame contours-en
Pyrometry of a propane flame using thin-filament velocimetry. The hottest parts of the flame are in a hollow cone-shaped area near its base and pointing upward.
  >1,750 K (1,480 °C)
  1,700 K (1,430 °C)
  1,600 K (1,330 °C)
  1,350 K (1,080 °C)
  1,100 K (830 °C)
  875 K (602 °C)
  750 K (477 °C)

Propane is a color- and odorless gas. At normal pressure it liquifies below it's boiling point at −42 °C and solidifies below it's melting point at −187,7 °C. Propane crystallizes in the space group P2(1)/n [18][19]. The low spacefilling of 58.7 % (at 90 K), due to the bad stacking properties of the molecule, is the reason for the particularly low melting point.

Propane undergoes combustion reactions in a similar fashion to other alkanes. In the presence of excess oxygen, propane burns to form water and carbon dioxide.

Propane combustion is much cleaner than that of coal or unleaded gasoline. Propane per BTU production of CO2 is almost as low as that of natural gas[21]. Propane burns hotter than home heating oil or diesel fuel because of the very high hydrogen content. The presence of C–C bonds, plus the multiple bonds of propylene and butylene, create organic exhausts besides carbon dioxide and water vapor during typical combustion. These bonds also cause propane to burn with a visible flame.

Energy content

The enthalpy of combustion of propane gas where all products return to standard state, for example where water returns to its liquid state at standard temperature (known as higher heating value), is (2219.2 ± 0.5) kJ/mol, or (50.33 ± 0.01) MJ/kg.[20] The enthalpy of combustion of propane gas where products do not return to standard state, for example where the hot gases including water vapor exit a chimney, (known as lower heating value) is −2043.455 kJ/mol.[22] The lower heat value is the amount of heat available from burning the substance where the combustion products are vented to the atmosphere; for example, the heat from a fireplace when the flue is open.

Density

The density of liquid propane at 25 °C (77 °F) is 0.493 g/cm3, which is equivalent to 4.11 pounds per U.S. liquid gallon or 493 g/L. Propane expands at 1.5% per 10 °F. Thus, liquid propane has a density of approximately 4.2 pounds per gallon (504 g/L) at 60 °F (15.6 °C).

Uses

Propane is a popular choice for barbecues and portable stoves because the low boiling point of −42 °C (−44 °F) makes it vaporize as soon as it is released from its pressurized container. Therefore, no carburetor or other vaporizing device is required; a simple metering nozzle suffices. Propane powers buses, forklifts, taxis, outboard boat motors, and ice resurfacing machines and is used for heat and cooking in recreational vehicles and campers. Propane is also used in some locomotive diesel engines as a fuel added into the turbocharger yielding much better combustion.

Since it can be transported easily, it is a popular fuel for home heat and backup electrical generation in sparsely populated areas that do not have natural gas pipelines. Many heavy-duty highway trucks use propane as a boost, where it is added through the turbocharger, to mix with diesel fuel droplets. Propane droplets' very high hydrogen content helps the diesel fuel to burn hotter and therefore more completely. This provides more torque, more horsepower, and a cleaner exhaust for the trucks. It is normal for a 7-liter medium-duty diesel truck engine to increase fuel economy by 20 to 33 percent when a propane boost system is used. It is cheaper because propane is much cheaper than diesel fuel. The longer distance a cross country trucker can travel on a full load of combined diesel and propane fuel means they can maintain federal hours of work rules with two fewer fuel stops in a cross country trip. Truckers, tractor pulling competitions, and farmers have been using a propane boost system for over forty years in North America.

International ships can reuse propane from ocean-going ships that transport LPG because as the sun evaporates the propane during the voyage, the international ship catches the evaporating propane gas and feeds it into the air intake system of the ship's diesel engines. This reduces bunker fuel consumption and the pollution created by the ships. There is an international agreement to use either propane or CNG as a mandatory additive to the bunker fuel for all ocean traveling ships beginning in 2020.

Propane tank 20lb
A 20 lb (9.1 kg) steel propane cylinder. This cylinder is fitted with an overfill prevention device (OPD) valve, as evidenced by the trilobular handwheel.

Propane is generally stored and transported in steel cylinders as a liquid with a vapor space above the liquid. The vapor pressure in the cylinder is a function of temperature. When gaseous propane is drawn at a high rate, the latent heat of vaporization required to create the gas will cause the bottle to cool. (This is why water often condenses on the sides of the bottle and then freezes). Since lightweight, high-octane propane vaporize before the heavier, low-octane propane, the ignition properties change as the cylinder empties. For these reasons, the liquid is often withdrawn using a dip tube.

Commercially available "propane" fuel, or LPG, is not pure. Typically in the United States and Canada, LPG is primarily propane (at least 90%), while the rest is mostly ethane, propylene, butane, and odorants including ethyl mercaptan.[23][24] This is the HD-5 standard, (Heavy Duty-5% maximum allowable propylene content, and no more than 5% butanes and ethane) defined by the American Society for Testing and Materials by its Standard 1835 for internal combustion engines. Not all products labeled "LPG" conform to this standard, however. In Mexico, for example, gas labeled "LPG" may consist of 60% propane and 40% butane. "The exact proportion of this combination varies by country, depending on international prices, on the availability of components and, especially, on the climatic conditions that favor LPG with higher butane content in warmer regions and propane in cold areas".[25]

Domestic and industrial fuel

150 gallon Propane Tank
Domestic spherical steel pressure vessel with a pressure regulator for propane storage in the United States. This example was installed on this property in 1974.
PropaneTruck2
A local delivery truck
Propane retail 06758
Retail sale of propane in the United States

Propane use is growing rapidly in non-industrialized areas of the world. Propane has replaced many older traditional fuel sources.

North American industries using propane include glass makers, brick kilns, poultry farms and other industries that need portable heat.

In rural areas of North America, as well as northern Australia, propane is used to heat livestock facilities, in grain dryers, and other heat-producing appliances. When used for heating or grain drying it is usually stored in a large, permanently-placed cylinder which is recharged by a propane-delivery truck. As of 2014, 6.2 million American households use propane as their primary heating fuel.[13]

In North America, local delivery trucks with an average cylinder size of 3,000 US gallons (11,000 L), fill up large cylinders that are permanently installed on the property, or other service trucks exchange empty cylinders of propane with filled cylinders. Large tractor-trailer trucks, with an average cylinder size of 10,000 US gallons (38,000 L), transport propane from the pipeline or refinery to the local bulk plant. The bobtail and transport are not unique to the North American market, though the practice is not as common elsewhere, and the vehicles are generally called tankers. In many countries, propane is delivered to consumers via small or medium-sized individual cylinders, while empty cylinders are removed for refilling at a central location.

Propene (also called propylene) can be a contaminant of commercial propane. Propane containing too much propene is not suited for most vehicle fuels. HD-5 is a specification that establishes a maximum concentration of 5% propene in propane. Propane and other LP gas specifications are established in ASTM D-1835.[26] All propane fuels include an odorant, almost always ethanethiol, so that people can easily smell the gas in case of a leak. Propane as HD-5 was originally intended for use as vehicle fuel. HD-5 is currently being used in all propane applications.

Refrigeration

Propane is also instrumental in providing off-the-grid refrigeration, as the energy source for a gas absorption refrigerator and is commonly used for camping and recreational vehicles. In addition, blends of pure, dry "isopropane" (R-290a) (isobutane/propane mixtures) and isobutane (R-600a) can be used as the circulating refrigerant in suitably constructed compressor-based refrigeration. Compared to fluorocarbons, propane has a negligible ozone depletion potential and very low global warming potential (having a value of only 3.3 times the GWP of carbon dioxide) and can serve as a functional replacement for R-12, R-22, R-134a, and other chlorofluorocarbon or hydrofluorocarbon refrigerants in conventional stationary refrigeration and air conditioning systems.[27] Because its global warming effect is far less than current refrigerants, propane was chosen as one of five replacement refrigerants approved by the EPA in 2015, for use in systems specially designed to handle its flammability.[28]

In motor vehicles

Such substitution is widely prohibited or discouraged in motor vehicle air conditioning systems, on the grounds that using flammable hydrocarbons in systems originally designed to carry non-flammable refrigerant presents a significant risk of fire or explosion.[29][30][31][32][33][34][35][36]

Vendors and advocates of hydrocarbon refrigerants argue against such bans on the grounds that there have been very few such incidents relative to the number of vehicle air conditioning systems filled with hydrocarbons.[37][38]

Motor fuel

Propane is also being used increasingly for vehicle fuels. In the U.S., over 190,000 on-road vehicles use propane, and over 450,000 forklifts use it for power. It is the third most popular vehicle fuel in the world,[39] behind gasoline and Diesel fuel. In other parts of the world, propane used in vehicles is known as autogas. In 2007, approximately 13 million vehicles worldwide use autogas.[39]

The advantage of propane in cars is its liquid state at a moderate pressure. This allows fast refill times, affordable fuel cylinder construction, and price ranges typically just over half that of gasoline. Meanwhile, it is noticeably cleaner (both in handling, and in combustion), results in less engine wear (due to carbon deposits) without diluting engine oil (often extending oil-change intervals), and until recently was a relative bargain in North America. The octane rating of propane is relatively high at 110. In the United States the propane fueling infrastructure is the most developed of all alternative vehicle fuels. Many converted vehicles have provisions for topping off from "barbecue bottles". Purpose-built vehicles are often in commercially owned fleets, and have private fueling facilities. A further saving for propane fuel vehicle operators, especially in fleets, is that pilferage is much more difficult than with gasoline or diesel fuels.

Propane is also used as fuel for small engines, especially those used indoors or in areas with insufficient fresh air and ventilation to carry away the more toxic exhaust of an engine running on gasoline or Diesel fuel. More recently, there have been lawn care products like string trimmers, lawn mowers and leaf blowers intended for outdoor use, but fueled by propane in order to reduce air pollution.[40]

Improvised explosive devices

Propane and propane cylinders have been used as improvised explosive devices in attacks and attempted attacks against schools and terrorist targets such as the Columbine High School massacre, 2012 Brindisi school bombing, the Discovery Communications headquarters hostage crisis and in car bombs.

Other uses

  • Propane is the primary flammable gas in blowtorches for soldering.
  • Propane is used as a feedstock for the production of base petrochemicals in steam cracking.
  • Propane is the primary fuel for hot air balloons.
  • It is used in semiconductor manufacture to deposit silicon carbide.
  • Propane is commonly used in theme parks and in the movie industry as an inexpensive, high-energy fuel for explosions and other special effects.
  • Propane is used as a propellant, relying on the expansion of the gas to fire the projectile. It does not ignite the gas. The use of a liquefied gas gives more shots per cylinder, compared to a compressed gas.
  • Propane is used as a propellant for many household aerosol sprays, including shaving creams and air fresheners.
  • Propane is a promising feedstock for the production of propylene[41][42] and acrylic acid.[43][44][45][46]

Hazards

Propane is a simple asphyxiant.[47] Unlike natural gas, propane is denser than air. It may accumulate in low spaces and near the floor. When abused as an inhalant, it may cause hypoxia (lack of oxygen), pneumonia, cardiac failure or cardiac arrest.[48][49] Propane has low toxicity since it is not readily absorbed and is not biologically active. Commonly stored under pressure at room temperature, propane and its mixtures will flash evaporate at atmospheric pressure and cool well below the freezing point of water. The cold gas, which appears white due to moisture condensing from the air, may cause frostbite.

Propane is denser than air. If a leak in a propane fuel system occurs, the gas will have a tendency to sink into any enclosed area and thus poses a risk of explosion and fire. The typical scenario is a leaking cylinder stored in a basement; the propane leak drifts across the floor to the pilot light on the furnace or water heater, and results in an explosion or fire. This property makes propane generally unsuitable as a fuel for boats.

One hazard associated with propane storage and transport is known as a BLEVE or boiling liquid expanding vapor explosion. The Kingman Explosion involved a railroad tank car in Kingman, Arizona in 1973 during a propane transfer. The fire and subsequent explosions resulted in twelve fatalities and numerous injuries.[50]

Comparison with natural gas

Propane is bought and stored in a liquid form (LPG), and thus fuel energy can be stored in a relatively small space. Compressed natural gas (CNG), largely methane, is another gas used as fuel, but it cannot be liquefied by compression at normal temperatures, as these are well above its critical temperature. As a gas, very high pressure is required to store useful quantities. This poses the hazard that, in an accident, just as with any compressed gas cylinder (such as a CO2 cylinder used for a soda concession) a CNG cylinder may burst with great force, or leak rapidly enough to become a self-propelled missile. Therefore, CNG is much less efficient to store, due to the large cylinder volume required. An alternative means of storing natural gas is as a cryogenic liquid in an insulated container as liquefied natural gas (LNG). This form of storage is at low pressure and is around 3.5 times as efficient as storing it as CNG. Unlike propane, if a spill occurs, CNG will evaporate and dissipate harmlessly because it is lighter than air. Propane is much more commonly used to fuel vehicles than is natural gas, because the equipment required costs less. Propane requires just 1,220 kilopascals (177 psi) of pressure to keep it liquid at 37.8 °C (100 °F).[51]

Retail cost

United States

As of October 2013, the retail cost of propane was approximately $2.37 per gallon, or roughly $25.95 per 1 million BTUs.[52] This means that filling a 500-gallon propane tank, which is what households that use propane as their main source of energy usually require, costs $948 (80% of 500 gallons or 400 gallons), a 7.5% increase on the 2012–2013 winter season average US price.[53] However, propane costs per gallon change significantly from one state to another: the Energy Information Administration (EIA) quotes a $2.995 per gallon average on the East Coast for October 2013,[54] while the figure for the Midwest was $1.860 for the same period.[55]

As of December 2015 the propane retail cost was approximately $1.97 per gallon.[56] This means that filling a 500-gallon propane tank to 80% capacity costs $788, a 16.9% decrease or $160 less from the November 2013 quote in this section. Similar regional differences in prices are present with the December 2015 EIA figure for the East Coast at $2.67 per gallon and the Midwest at $1.43 per gallon.[56]

As of August 2018 the average US propane retail cost was approximately $2.48 per gallon. The wholesale price of propane in the U.S. always drops in the summer as most homes don't require it for home heating. The wholesale price of propane in the summer of 2018 has been between 86 cents to 96 cents per U.S. gallon, based on a truckload or railway car load. The price for home heating is exactly double that price, so at 95 cents per gallon wholesale, that would mean a home delivered price of $1.90 per gallon if you order 500 gallons at a time. Prices in the midwest are always cheaper than California. Prices for home delivery always go up near the end of August or the first few days of September when people start ordering their home tanks to be filled.[57]

See also

References

  1. ^ a b "Front Matter". Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 4. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4. Similarly, the retained names ‘ethane’, ‘propane’, and ‘butane’ were never replaced by systematic names ‘dicarbane’, ‘tricarbane’, and ‘tetracarbane’ as recommended for analogues of silane, ‘disilane’; phosphane, ‘triphosphane’; and sulfane, ‘tetrasulfane’.
  2. ^ Record of Propane in the GESTIS Substance Database of the Institute for Occupational Safety and Health
  3. ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0524". National Institute for Occupational Safety and Health (NIOSH).
  4. ^ GOV, NOAA Office of Response and Restoration, US. "PROPANE - CAMEO Chemicals - NOAA". cameochemicals.noaa.gov.
  5. ^ "Comptes rendus hebdomadaires des séances de l'Académie des sciences" (in French). 140. 1905.
  6. ^ Roscoe, H.E.; Schorlemmer, C. (1881). Treatise on Chemistry. 3. Macmillan. pp. 144–145.
  7. ^ Watts, H. (1868). Dictionary of Chemistry. 4. p. 385.
  8. ^ "GAS PLANT IN STEEL BOTTLE.; Dr. Snelling's Process Gives Month's Supply in Liquid Form". The New York Times. April 1, 1912. p. 9. Retrieved 2007-12-22.
  9. ^ a b National Propane Gas Association. "The History of Propane". Archived from the original on January 11, 2011. Retrieved 2007-12-22.CS1 maint: Unfit url (link)
  10. ^ "The First Fifty Years of LP-Gas: An Industry Chronology" (PDF). LPGA Times. January 1962. Archived from the original (PDF) on 2006-10-07., Page 17.
  11. ^ Propane Education & Research Council. "Fact Sheet – The History of Propane". Archived from the original on February 16, 2004. Retrieved 2007-12-22.CS1 maint: Unfit url (link)
  12. ^ "Online Etymology Dictionary entry for propane". Etymonline.com. Retrieved 2010-10-29.
  13. ^ a b Sloan, Michael. "2016 Propane Market Outlook" (PDF). Propane Education and Research Council. Retrieved 19 January 2018.
  14. ^ Argonne National Laborator (1999). "Salt Cavern Information Center". Archived from the original on 2007-12-23. Retrieved 2007-12-22.
  15. ^ Propane Education & Research Council. "History of Propane". Archived from the original on 1 November 2010. Retrieved 22 May 2012.
  16. ^ MIT Technology Review. "A New Biofuel: Propane". Retrieved 2015-07-15.
  17. ^ "Neste delivers first batch of 100% renewable propane to European market". 2018-03-19. Retrieved 3 December 2018.
  18. ^ geometry of crystalline propane
  19. ^ Boese R, Weiss HC, Blaser D (1999). "The melting point alternation in the short-chain n-alkanes: Single-crystal X-ray analyses of propane at 30 K and of n-butane to n-nonane at 90 K". Angew Chem Int Ed. 38: 988–992. doi:10.1002/(SICI)1521-3773(19990401)38:7<988::AID-ANIE988>3.3.CO;2-S.
  20. ^ a b Propane. NIST Standard Reference Data referring to Pittam, D. A.; Pilcher, G. (1972). "Measurements of heats of combustion by flame calorimetry. Part 8.—Methane, ethane, propane, n-butane and 2-methylpropane". Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases. 68: 2224. doi:10.1039/f19726802224. and Rossini, F.D. (1934). "Calorimetric determination of the heats of combustion of ethane, propane, normal butane, and normal pentane". Bureau of Standards Journal of Research. 12 (6): 735–750. doi:10.6028/jres.012.059.
  21. ^ United States Energy Information Association. "How much carbon dioxide is produced when different fuels are burned". Retrieved 2019-03-25.
  22. ^ Ҫengel, Yunus A.; Boles, Michael A. (2006). Thermodynamics: An Engineering Approach (Fifth ed.). McGrawHill. p. 925. ISBN 978-0-07-288495-1.
  23. ^ Amerigas. "Amerigas Material Safety Data Sheet for Odorized Propane" (PDF). Archived from the original (PDF) on 2011-12-09. Retrieved 2011-10-24.
  24. ^ Suburban Propane. "Suburban Propane Material Safety Data Sheet for Commercial Odorized Propane" (PDF). Archived from the original (PDF) on 2011-10-25. Retrieved 2011-10-24.
  25. ^ Mexican Ministry of Energy. "Liquefied Petroleum Gas Market Outlook 2008–2017" (PDF). Mexican Ministry of Energy. Archived from the original (PDF) on 2012-05-10. Retrieved 2012-05-17.
  26. ^ "ASTM D1835 - 16 Standard Specification for Liquefied Petroleum (LP) Gases". www.astm.org.
  27. ^ "European Commission on retrofit refrigerants for stationary applications" (PDF). Archived from the original on August 5, 2009. Retrieved 2010-10-29.CS1 maint: Unfit url (link)
  28. ^ Why Your Fridge Pollutes and How It's Changing By Wendy Koch, National Geographic March 6, 2015
  29. ^ "U.S. EPA hydrocarbon-refrigerants FAQ". Epa.gov. Retrieved 2010-10-29.
  30. ^ Compendium of hydrocarbon-refrigerant policy statements, October 2006. vasa.org.au
  31. ^ "MACS bulletin: hydrocarbon refrigerant usage in vehicles" (PDF). Archived from the original (PDF) on 2011-01-05. Retrieved 2010-10-29.
  32. ^ "Society of Automotive Engineers hydrocarbon refrigerant bulletin". Sae.org. 2005-04-27. Retrieved 2010-10-29.
  33. ^ "Shade Tree Mechanic on hydrocarbon refrigerants". Shadetreemechanic.com. 2005-04-27. Retrieved 2010-10-29.
  34. ^ "Saskatchewan Labour bulletin on hydrocarbon refrigerants in vehicles". Labour.gov.sk.ca. 2010-06-29. Archived from the original on 2009-07-01. Retrieved 2010-10-29.
  35. ^ VASA on refrigerant legality & advisability. vasa.org.au
  36. ^ "Queensland (Australia) government warning on hydrocarbon refrigerants" (PDF). Energy.qld.gov.au. Archived from the original on December 17, 2008. Retrieved 2010-10-29.CS1 maint: Unfit url (link)
  37. ^ "New South Wales (Australia) Parliamentary record, 16 October 1997". Parliament.nsw.gov.au. 1997-10-16. Archived from the original on 1 July 2009. Retrieved 2010-10-29.
  38. ^ "New South Wales (Australia) Parliamentary record, 29 June 2000". Parliament.nsw.gov.au. Archived from the original on 22 May 2005. Retrieved 2010-10-29.
  39. ^ a b Propane Education & Research Council. "Autogas". PERC. Archived from the original on September 23, 2010. Retrieved 2012-05-17.CS1 maint: Unfit url (link)
  40. ^ "Facts About Propane: America's Exceptional Energy" (PDF). National Propane Gas Association. April 2001. Retrieved December 15, 2016.
  41. ^ Hernández, Juan Pablo; Echavarría, Adriana; Palacio, Luz Amparo (2013). "Synthesis of two new Nickel and Copper- Nickel vanadates used for propane oxidative dehydrogenation". Revista Facultad de Ingeniería Universidad de Antioquia (67): 137–145. ISSN 0120-6230.
  42. ^ Zea, Hugo; Figueiredo, Jose L.; Carballo, Luis (2011). "PROMOTING EFFECT OF Mo ON Pd / g-Al2O3 SUPPORTED CATALYSTS IN THE OXIDATIVE DEHYDROGENATION OF PROPANE". DYNA. 78 (170): 159–166. ISSN 0012-7353.
  43. ^ Naumann d'Alnoncourt, Raoul; Csepei, Lénárd-István; Hävecker, Michael; Girgsdies, Frank; Schuster, Manfred E; Schlögl, Robert; Trunschke, Annette (2014). "The reaction network in propane oxidation over phase-pure MoVTeNb M1 oxide catalysts" (PDF). Journal of Catalysis. 311: 369–385. doi:10.1016/j.jcat.2013.12.008. hdl:11858/00-001M-0000-0014-F434-5.
  44. ^ Amakawa, Kazuhiko; Kolen'Ko, Yury V; Villa, Alberto; Schuster, Manfred E/; Csepei, Lénárd-István; Weinberg, Gisela; Wrabetz, Sabine; Naumann d'Alnoncourt, Raoul; Girgsdies, Frank; Prati, Laura; Schlögl, Robert; Trunschke, Annette (2013). "Multifunctionality of Crystalline MoV(TeNb) M1 Oxide Catalysts in Selective Oxidation of Propane and Benzyl Alcohol". ACS Catalysis. 3 (6): 1103–1113. doi:10.1021/cs400010q.
  45. ^ Hävecker, Michael; Wrabetz, Sabine; Kröhnert, Jutta; Csepei, Lenard-Istvan; Naumann d'Alnoncourt, Raoul; Kolen'Ko, Yury V; Girgsdies, Frank; Schlögl, Robert; Trunschke, Annette (2012). "Surface chemistry of phase-pure M1 MoVTeNb oxide during operation in selective oxidation of propane to acrylic acid" (PDF). Journal of Catalysis. 285: 48–60. doi:10.1016/j.jcat.2011.09.012. hdl:11858/00-001M-0000-0012-1BEB-F.
  46. ^ Kinetic studies of propane oxidation on Mo and V based mixed oxide catalysts (PDF). 2011.
  47. ^ "Propane". The National Institute for Occupational Safety and Health (NIOSH). Retrieved 2016-05-12. Propane is a simple asphyxiant and does not present an IDLH hazard at concentrations below its lower explosive limit (LEL). The chosen IDLH is based on the LEL of 21,000 ppm rounded down to 20,000 ppm.
  48. ^ "Inhalants – Facts and Statistics". Greater Dallas Council on Alcohol & Drug Abuse. March 4, 2006. Archived from the original on 2009-04-08.
  49. ^ "Inhalants". National Inhalant Prevention Coalition.
  50. ^ "The Disaster Story". Kingman Historic District. Retrieved 1 July 2013.
  51. ^ "Propane Vapor Pressure". The Engineering ToolBox. 2005. Retrieved 2008-07-28.
  52. ^ US Energy Information Administration (November 12, 2013). "Heating Oil and Propane Prices".
  53. ^ Propane Deal (November 12, 2013). "Current Propane Prices".
  54. ^ US Energy Information Administration (November 12, 2013). "East Coast Heating Oil and Propane Prices".
  55. ^ US Energy Information Administration (November 12, 2013). "Midwest Heating Oil and Propane Prices".
  56. ^ a b US Energy Information Administration (December 12, 2015). "Residential Propane: Weekly Heating Oil and Propane Prices (October – March)".
  57. ^ US Energy Information Administration (August 11, 2018). "Residential Propane: Weekly Heating Oil and Propane Prices (October – March)".

External links

1-Methylamino-1-(3,4-methylenedioxyphenyl)propane

1-Methylamino-1-(3,4-methylenedioxyphenyl)propane or M-ALPHA is an empathogen, reported by Alexander Shulgin in his book PIHKAL as a positional isomer of MDMA, and subsequently found being sold as a designer drug in the UK in 2010, and reported to the EMCDDA new drug monitoring service. It was described by Alexander Shulgin as similar in action to its demethylated homologue, ALPHA, but with roughly twice the duration and twice the potency.

Absorption refrigerator

An absorption refrigerator is a refrigerator that uses a heat source (e.g., solar energy, a fossil-fueled flame, waste heat from factories, or district heating systems) to provide the energy needed to drive the cooling process.

The principle can also be used to air-condition buildings using the waste heat from a gas turbine or water heater. Using waste heat from a gas turbine makes the turbine very efficient because it first produces electricity, then hot water, and finally, air-conditioning (called cogeneration/trigeneration).

The American National Standards Institute standard for the absorption refrigerator is given by the ANSI/AHRI standard 560–2000.

Alternative fuel

Alternative fuels, known as non-conventional and advanced fuels, are any materials or substances that can be used as fuels, other than conventional fuels like; fossil fuels (petroleum (oil), coal, and natural gas), as well as nuclear materials such as uranium and thorium, as well as artificial radioisotope fuels that are made in nuclear reactors.

Some well-known alternative fuels include bio-diesel, bio-alcohol (methanol, ethanol, butane), refuse-derived fuel, chemically stored electricity (batteries and fuel cells), hydrogen, non-fossil methane, non-fossil natural gas, vegetable oil, propane and other biomass sources.

Autogas

Autogas is the common name for liquefied petroleum gas (LPG) when it is used as a fuel in internal combustion engines in vehicles as well as in stationary applications such as generators. It is a mixture of propane and butane.

Autogas is widely used as a "green" fuel, as its use reduces CO2 exhaust emissions by around 15% compared to petrol. One litre of petrol produces 2.3 kg of CO2 when burnt, whereas the equivalent amount of autogas (1.33 litre due to lower density of autogas) produces only 1.5 * 1.33 = 2 kg of CO2 when burnt. CO emissions are 30% lower, compared to petrol and NO x by 50%. It has an octane rating (MON/RON) that is between 90 and 110 and an energy content (higher heating value—HHV) that is between 25.5 megajoules per litre (for pure propane) and 28.7 megajoules per litre (for pure butane) depending upon the actual fuel composition.

Autogas is the third most popular automotive fuel in the world, with approximately 16 million of 600 million passenger cars powered using the fuel, representing less than 3% of the total market share. Approximately half of all autogas-fueled passenger vehicles are in the five largest markets (in descending order): Turkey, South Korea, Poland, Italy, and Australia.

Barbecue grill

A barbecue grill is a device that cooks food by applying heat from below. There are several varieties of grills, with most falling into one of two categories: gas-fueled or charcoal. There is debate over which method yields superior results.

Bisphenol

The bisphenols () are a group of chemical compounds with two hydroxyphenyl functionalities. Most of them are based on diphenylmethane. The exceptions are bisphenol S, P, and M. "Bisphenol" is a common name; the letter following refers to one of the reactants. Bisphenol A is the most popular representative of this group, often simply called "bisphenol."

Bisphenol A diglycidyl ether

Bisphenol A diglycidyl ether (commonly abbreviated BADGE or DGEBA) is an organic compound used as constituent of epoxy resins. The compound is a colorless solid (commercial samples can appear yellow) that melts slightly above room temperature.

Glycerol

Glycerol (; also called glycerine or glycerin; see spelling differences) is a simple polyol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in many lipids which are known as glycerides. It is widely used in the food industry as a sweetener and humectant in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature.

Hank Hill

Henry Rutherford "Hank" Hill (born April 19, 1954), is a fictional character and the main protagonist of the Fox animated television series King of the Hill. He lives in the fictional town of Arlen, Texas with his family and works as the assistant manager of a local branch of Strickland Propane. He likes to drink beer in the alley behind his house with his friends. He is voiced by series creator Mike Judge. The Economist described Hank Hill as one of the wisest people on television, and in 1997 Texas Monthly included him on its annual list of the most influential Texans.

Hot air balloon

A hot air balloon is a lighter-than-air aircraft consisting of a bag, called an envelope, which contains heated air. Suspended beneath is a gondola or wicker basket (in some long-distance or high-altitude balloons, a capsule), which carries passengers and a source of heat, in most cases an open flame caused by burning liquid propane. The heated air inside the envelope makes it buoyant since it has a lower density than the colder air outside the envelope. As with all aircraft, hot air balloons cannot fly beyond the atmosphere. The envelope does not have to be sealed at the bottom, since the air inside the envelope there is at about the same pressure as the surrounding air. In modern sport balloons the envelope is generally made from nylon fabric and the inlet of the balloon (closest to the burner flame) is made from a fire resistant material such as Nomex. Modern balloons have been made in all kinds of shapes, such as rocket ships and the shapes of various commercial products, though the traditional shape is used for most non-commercial, and many commercial, applications.

The hot air balloon is the first successful human-carrying flight technology. The first untethered manned hot air balloon flight was performed by Jean-François Pilâtre de Rozier and François Laurent d'Arlandes on November 21, 1783, in Paris, France, in a balloon created by the Montgolfier brothers. The first hot-air balloon flown in the Americas was launched from the Walnut Street Jail in Philadelphia on January 9, 1793 by the French aeronaut Jean Pierre Blanchard. Hot air balloons that can be propelled through the air rather than simply drifting with the wind are known as thermal airships.

Isobutane

Isobutane, also known as i-butane, 2-methylpropane or methylpropane, is a chemical compound with molecular formula HC(CH3)3. It is an isomer of butane. It is the simplest alkane with a tertiary carbon. Isobutane is used as a precursor molecule in the petrochemical industry, for example in the synthesis of isooctane.

King of the Hill

King of the Hill is an American animated sitcom created by Mike Judge and Greg Daniels for the Fox Broadcasting Company that ran from January 12, 1997, to May 6, 2010. It centers on the Hills, a middle-class American family in the fictional city of Arlen, Texas. Patriarch and main character Hank Hill, who works as assistant manager at Strickland Propane, is the everyman and general protagonist of the series. His modest conservative views and biases often clash with that of his wife, Peggy; his son, Bobby; his father, Cotton; his niece, Luanne; his boss, Buck Strickland; and his neighbor, Kahn. Hank is friends with other residents on his block, especially Bill Dauterive, Dale Gribble, and Jeff Boomhauer, all of whom he has known since elementary school. It attempts to maintain a realistic approach, seeking humor in the conventional and mundane aspects of everyday life.

Judge began creating King of the Hill during his time making the MTV series Beavis and Butt-Head, which he also created and voiced. After pitching the pilot to Fox, Judge was paired with Greg Daniels, an experienced writer who previously worked on The Simpsons. The series debuted on the Fox network as a mid-season replacement in 1997, quickly becoming a hit. The series' popularity led to worldwide syndication, and reruns aired on Adult Swim from 2009 until 2018. Since July 24, 2018, reruns began airing on Comedy Central. The show became one of Fox's longest-running series (third-longest as an animated series, behind The Simpsons and Family Guy). A total of 259 episodes aired over the course of its 13 seasons. The final episode aired on Fox on September 13, 2009. Four episodes from the final season were to have aired on Fox, but later premiered in nightly syndication from May 3 to 6, 2010.

In 2007, it was named by Time magazine as one of the top 100 greatest television shows of all time. King of the Hill won two Emmy Awards and was nominated for seven. The series' celebrity guest stars include Chuck Mangione (playing a fictionalized version of himself), Tom Petty (playing the recurring character Lucky), and numerous country music artists.

Liquefied petroleum gas

Liquefied petroleum gas or liquid petroleum gas (LPG or LP gas), also referred to as simply propane or butane, are flammable mixtures of hydrocarbon gases used as fuel in heating appliances, cooking equipment, and vehicles.

It is increasingly used as an aerosol propellant and a refrigerant, replacing chlorofluorocarbons in an effort to reduce damage to the ozone layer. When specifically used as a vehicle fuel it is often referred to as autogas.

Varieties of LPG bought and sold include mixes that are mostly propane (C3H8), mostly butane (C4H10), and, most commonly, mixes including both propane and butane. In the northern hemisphere winter, the mixes contain more propane, while in summer, they contain more butane. In the United States, mainly two grades of LPG are sold: commercial propane and HD-5. These specifications are published by the Gas Processors Association (GPA) and the American Society of Testing and Materials (ASTM). Propane/butane blends are also listed in these specifications.

Propylene, butylenes and various other hydrocarbons are usually also present in small concentrations. HD-5 limits the amount of propylene that can be placed in LPG to 5%, and is utilized as an autogas specification. A powerful odorant, ethanethiol, is added so that leaks can be detected easily. The internationally recognized European Standard is EN 589. In the United States, tetrahydrothiophene (thiophane) or amyl mercaptan are also approved odorants, although neither is currently being utilized.

LPG is prepared by refining petroleum or "wet" natural gas, and is almost entirely derived from fossil fuel sources, being manufactured during the refining of petroleum (crude oil), or extracted from petroleum or natural gas streams as they emerge from the ground. It was first produced in 1910 by Dr. Walter Snelling, and the first commercial products appeared in 1912. It currently provides about 3% of all energy consumed, and burns relatively cleanly with no soot and very few sulfur emissions. As it is a gas, it does not pose ground or water pollution hazards, but it can cause air pollution. LPG has a typical specific calorific value of 46.1 MJ/kg compared with 42.5 MJ/kg for fuel oil and 43.5 MJ/kg for premium grade petrol (gasoline). However, its energy density per volume unit of 26 MJ/L is lower than either that of petrol or fuel oil, as its relative density is lower (about 0.5–0.58 kg/L, compared to 0.71–0.77 kg/L for gasoline).

As its boiling point is below room temperature, LPG will evaporate quickly at normal temperatures and pressures and is usually supplied in pressurised steel vessels. They are typically filled to 80–85% of their capacity to allow for thermal expansion of the contained liquid. The ratio between the volumes of the vaporized gas and the liquefied gas varies depending on composition, pressure, and temperature, but is typically around 250:1. The pressure at which LPG becomes liquid, called its vapour pressure, likewise varies depending on composition and temperature; for example, it is approximately 220 kilopascals (32 psi) for pure butane at 20 °C (68 °F), and approximately 2,200 kilopascals (320 psi) for pure propane at 55 °C (131 °F). LPG is heavier than air, unlike natural gas, and thus will flow along floors and tend to settle in low spots, such as basements. There are two main dangers from this. The first is a possible explosion if the mixture of LPG and air is within the explosive limits and there is an ignition source. The second is suffocation due to LPG displacing air, causing a decrease in oxygen concentration.

A "full" LPG cylinder contains 85% liquid, the ullage volume will contain vapour at a pressure that varies with temperature.

List of King of the Hill episodes

King of the Hill is an American animated television series created by Mike Judge and Greg Daniels. The series focuses on the Hills, a middle-class American family in the fictional city of Arlen, Texas. It originally aired on Fox from January 12, 1997 to September 13, 2009; with four episodes from the final season premiering in syndication from May 3 to May 6, 2010. A total of 259 episodes aired over the course of 13 seasons.

Nitroglycerin

Nitroglycerin (NG), also known as nitroglycerine, trinitroglycerin (TNG), nitro, glyceryl trinitrate (GTN), or 1,2,3-trinitroxypropane, is a dense, colorless, oily, explosive liquid most commonly produced by nitrating glycerol with white fuming nitric acid under conditions appropriate to the formation of the nitric acid ester. Chemically, the substance is an organic nitrate compound rather than a nitro compound, yet the traditional name is often retained. Invented in 1847, nitroglycerin has been used as an active ingredient in the manufacture of explosives, mostly dynamite, and as such it is employed in the construction, demolition, and mining industries. Since the 1880s, it has been used by the military as an active ingredient, and a gelatinizer for nitrocellulose, in some solid propellants, such as cordite and ballistite.

Nitroglycerin is a major component in double-based smokeless gunpowders used by reloaders. Combined with nitrocellulose, hundreds of powder combinations are used by rifle, pistol, and shotgun reloaders.

In medicine for over 130 years, nitroglycerin has been used as a potent vasodilator (dilation of the vascular system) to treat heart conditions, such as angina pectoris and chronic heart failure. Though it was previously known that these beneficial effects are due to nitroglycerin being converted to nitric oxide, a potent venodilator, the enzyme for this conversion was not discovered to be mitochondrial aldehyde dehydrogenase (ALDH2) until 2002. Nitroglycerin is available in sublingual tablets, sprays, ointments, and patches.

Oxy-fuel welding and cutting

Oxy-fuel welding (commonly called oxyacetylene welding, oxy welding, or gas welding in the U.S.) and oxy-fuel cutting are processes that use fuel gases (or liquid fuels such as gasoline) and oxygen to weld or cut metals. French engineers Edmond Fouché and Charles Picard became the first to develop oxygen-acetylene welding in 1903. Pure oxygen, instead of air, is used to increase the flame temperature to allow localized melting of the workpiece material (e.g. steel) in a room environment. A common propane/air flame burns at about 2,250 K (1,980 °C; 3,590 °F), a propane/oxygen flame burns at about 2,526 K (2,253 °C; 4,087 °F), an oxyhydrogen flame burns at 3,073 K (2,800 °C; 5,072 °F) and an acetylene/oxygen flame burns at about 3,773 K (3,500 °C; 6,332 °F).During the early 20th century, before the development and availability of coated arc welding electrodes in the late 1920s that were capable of making sound welds in steel, oxy-acetylene welding was the only process capable of making welds of exceptionally high quality in virtually all metals in commercial use at the time. These included not only carbon steel but also alloy steels, cast iron, aluminum, and magnesium. In recent decades it has been superseded in almost all industrial uses by various arc welding methods offering greater speed and, in the case of gas tungsten arc welding, the capability of welding very reactive metals such as titanium. Oxy-acetylene welding is still used for metal-based artwork and in smaller home-based shops, as well as situations where accessing electricity (e.g., via an extension cord or portable generator) would present difficulties. The oxy-acetylene (and other oxy-fuel gas mixtures) welding torch remains a mainstay heat source for manual brazing and braze welding, as well as metal forming, preparation, and localized heat treating. In addition, oxy-fuel cutting is still widely used, both in heavy industry and light industrial and repair operations. (See Oxy Gasoline Cutting )

In oxy-fuel welding, a welding torch is used to weld metals. Welding metal results when two pieces are heated to a temperature that produces a shared pool of molten metal. The molten pool is generally supplied with additional metal called filler. Filler material depends upon the metals to be welded.

In oxy-fuel cutting, a torch is used to heat metal to its kindling temperature. A stream of oxygen is then trained on the metal, burning it into a metal oxide that flows out of the kerf as slag.Torches that do not mix fuel with oxygen (combining, instead, atmospheric air) are not considered oxy-fuel torches and can typically be identified by a single tank (oxy-fuel cutting requires two isolated supplies, fuel and oxygen). Most metals cannot be melted with a single-tank torch. Consequently, single-tank torches are typically suitable for soldering and brazing but not for welding.

Propene

Propene, also known as propylene or methyl ethylene, is an unsaturated organic compound having the chemical formula . It has one double bond, and is the second simplest member of the alkene class of hydrocarbons. It is a colorless gas with a faint petroleum-like odor

Propylene glycol

Propylene glycol (IUPAC name: propane-1,2-diol) is a synthetic organic compound with the chemical formula C3H8O2. It is a viscous, colorless liquid which is nearly odorless but possesses a faintly sweet taste. Chemically it is classed as a diol alcohol that is miscible with a broad range of solvents, including water, acetone, and chloroform. It falls within the same class of compounds as alcohols.It is produced on a large scale and is primarily used in the production of polymers, but also used in food processing, pharma and in airplane deicing applications. In the European Union, it has the E-number E1520 for food applications. For cosmetics and pharmacology, the number is E490. Propylene glycol is also present in propylene glycol alginate which is known as E405. Propylene glycol is a compound which is generally recognized as safe (GRAS) by the U.S. Food and Drug Administration (FDA) under 21 CFR x184.1666 and is also approved by FDA for certain uses as an indirect food additive. Propylene glycol is approved and used as a vehicle for topical, oral and some intravenous pharmaceutical preparations in U.S. and in Europe.

The compound is sometimes called (alpha) α-propylene glycol to distinguish it from the isomer propane-1,3-diol, known as (beta) β-propylene glycol.

Toronto propane explosion

The Toronto propane explosion (also known as the Sunrise Propane incident) was a series of explosions and ensuing fire that took place on the morning of August 10, 2008, in Downsview, North York, Toronto, Ontario, Canada. The explosions occurred at the Sunrise Propane Industrial Gases propane facility, located near Keele Street and Wilson Avenue around 03:50 ET. The blasts caused thousands of people to be evacuated from their homes and cost C$1.8 million to clean up, half of which was paid by the province of Ontario. An employee of Sunrise died in the initial explosions and a firefighter died of cardiac arrest the next day while at the scene.

Alkali metal hydrides
Alkaline earth hydrides
Group 13 hydrides
Group 14 hydrides
Pnictogen hydrides
Hydrogen chalcogenides
Hydrogen halides
Transition metal hydrides
Lanthanide hydrides
Actinide hydrides
Types
Infrastructure
Uses
Compressed-air engine
Electric motor
Biofuel ICE
Hydrogen
Others
Multiple-fuel
Documentaries
See also
Alcohols
Barbiturates
Benzodiazepines
Carbamates
Flavonoids
Imidazoles
Kava constituents
Monoureides
Neuroactive steroids
Nonbenzodiazepines
Phenols
Piperidinediones
Pyrazolopyridines
Quinazolinones
Volatiles/gases
Others/unsorted

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