Misplaced Pages

#906093

72-457: Gasoline ( North American English ) or petrol ( Commonwealth English ) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines . When formulated as a fuel for engines , gasoline is chemically composed of organic compounds derived from the fractional distillation of petroleum and later chemically enhanced with gasoline additives . It

144-409: A Wurtz reaction of 1,6-dibromohexane. Although rather unreactive, cyclohexane undergoes autoxidation to give a mixture of cyclohexanone and cyclohexanol . The cyclohexanone–cyclohexanol mixture, called " KA oil ", is a raw material for adipic acid and caprolactam , precursors to nylon . Several million kilograms of cyclohexanone and cyclohexanol are produced annually. It is used as

216-454: A bromine number of 10 or above can be protected with the combination of unhindered or partially hindered phenols and oil-soluble strong amine bases, such as hindered phenols. "Stale" gasoline can be detected by a colorimetric enzymatic test for organic peroxides produced by oxidation of the gasoline. Gasolines are also treated with metal deactivators , which are compounds that sequester (deactivate) metal salts that otherwise accelerate

288-422: A plastic crystal , which means the molecules retain some rotational degree of freedom. The low-temperature (below 186 K) phase II is ordered. Two other low-temperature (metastable) phases III and IV have been obtained by application of moderate pressures above 30 MPa, where phase IV appears exclusively in deuterated cyclohexane (application of pressure increases the values of all transition temperatures). Here Z

360-455: A condition called "stale fuel". Gasoline containing ethanol is especially subject to absorbing atmospheric moisture, then forming gums, solids, or two phases (a hydrocarbon phase floating on top of a water-alcohol phase). The presence of these degradation products in the fuel tank or fuel lines plus a carburetor or fuel injection components makes it harder to start the engine or causes reduced engine performance On resumption of regular engine use,

432-449: A controlled process called deflagration . However, the unburned mixture may autoignite by pressure and heat alone, rather than igniting from the spark plug at exactly the right time, causing a rapid pressure rise that can damage the engine. This is often referred to as engine knocking or end-gas knock. Knocking can be reduced by increasing the gasoline's resistance to autoignition , which is expressed by its octane rating. Octane rating

504-459: A convenient crystal-crystal transition at −87.1 °C. Cyclohexane vapour is used in vacuum carburizing furnaces, in heat treating equipment manufacture. The 6-vertex edge ring does not conform to the shape of a perfect hexagon . The conformation of a flat 2D planar hexagon has considerable strain because the C-H bonds would be eclipsed . Therefore, to reduce torsional strain , cyclohexane adopts

576-443: A fine mist. Quality gasoline should be stable for six months if stored properly, but can degrade over time. Gasoline stored for a year will most likely be able to be burned in an internal combustion engine without too much trouble. However, the effects of long-term storage will become more noticeable with each passing month until a time comes when the gasoline should be diluted with ever-increasing amounts of freshly made fuel so that

648-500: A gasoline depends upon: The various refinery streams blended to make gasoline have different characteristics. Some important streams include the following: The terms above are the jargon used in the oil industry, and the terminology varies. Currently, many countries set limits on gasoline aromatics in general, benzene in particular, and olefin (alkene) content. Such regulations have led to an increasing preference for alkane isomers, such as isomerate or alkylate, as their octane rating

720-468: A greater volume fraction of aromatics. Finished marketable gasoline is traded (in Europe) with a standard reference of 0.755 kilograms per liter (6.30 lb/U.S. gal), (7,5668 lb/ imp gal) its price is escalated or de-escalated according to its actual density. Because of its low density, gasoline floats on water, and therefore water cannot generally be used to extinguish a gasoline fire unless applied in

792-412: A growing annual target of total gallons blended. Although the mandate does not require a specific percentage of ethanol, annual increases in the target combined with declining gasoline consumption have caused the typical ethanol content in gasoline to approach 10 percent. Most fuel pumps display a sticker that states that the fuel may contain up to 10 percent ethanol, an intentional disparity that reflects

SECTION 10

#1732787364907

864-574: A high compression ratio. A high expansion ratio is also one of the two key reasons for the efficiency of diesel engines , along with the elimination of pumping losses due to throttling of the intake airflow. The lower energy content of LPG by liquid volume in comparison to gasoline is due mainly to its lower density. This lower density is a property of the lower molecular weight of propane (LPG's chief component) compared to gasoline's blend of various hydrocarbon compounds with heavier molecular weights than propane. Conversely, LPG's energy content by weight

936-401: A higher compression ratio through the concomitant higher expansion ratio on the power stroke, which is by far the greater effect. The higher expansion ratio extracts more work from the high-pressure gas created by the combustion process. An Atkinson cycle engine uses the timing of the valve events to produce the benefits of a high expansion ratio without the disadvantages, chiefly detonation, of

1008-608: A large influence on Canadian English from its early roots. Some terms in North American English are used almost exclusively in Canada and the United States (for example, the terms diaper and gasoline are widely used instead of nappy and petrol ). Although many English speakers from outside North America regard those terms as distinct Americanisms , they are just as common in Canada, mainly due to

1080-454: A large percentage of cars from the 1980s and early 1990s which ran on leaded gasoline were still in use, along with cars that could run on unleaded fuel. However, the declining number of such cars on British roads saw many gasoline stations withdrawing LRP from sale by 2003. Methylcyclopentadienyl manganese tricarbonyl (MMT) is used in Canada and the U.S. to boost octane rating. Its use in the U.S. has been restricted by regulations, although it

1152-642: A nation with a good supply of high-octane gasoline would have the advantage in air power. In 1943, the Rolls-Royce Merlin aero engine produced 980 kilowatts (1,320 hp) using 100 RON fuel from a modest 27 liters (1,600 cu in) displacement. By the time of Operation Overlord , both the RAF and USAAF were conducting some operations in Europe using 150 RON fuel (100/150 avgas ), obtained by adding 2.5 percent aniline to 100-octane avgas. By this time,

1224-416: A representative species, performs the chemical reaction: By weight, combustion of gasoline releases about 46.7 megajoules per kilogram (13.0  kWh /kg; 21.2 MJ/ lb ) or by volume 33.6 megajoules per liter (9.3 kWh/L; 127 MJ/U.S. gal; 121,000 BTU/U.S. gal), quoting the lower heating value . Gasoline blends differ, and therefore actual energy content varies according to

1296-680: A single category. Canadians are generally tolerant of both British and American spellings, with British spellings of certain words (e.g., colour ) preferred in more formal settings and in Canadian print media; for some other words the American spelling prevails over the British (e.g., tire rather than tyre ). Dialects of American English spoken by United Empire Loyalists who fled the American Revolution (1775–1783) have had

1368-443: A solvent in some brands of correction fluid. Cyclohexane is sometimes used as a non-polar organic solvent, although n-hexane is more widely used for this purpose. It is frequently used as a recrystallization solvent, as many organic compounds exhibit good solubility in hot cyclohexane and poor solubility at low temperatures. Cyclohexane is also used for calibration of differential scanning calorimetry (DSC) instruments, because of

1440-423: A three-dimensional structure known as the chair conformation , which rapidly interconvert at room temperature via a process known as a chair flip . During the chair flip, there are three other intermediate conformations that are encountered: the half-chair, which is the most unstable conformation, the more stable boat conformation, and the twist-boat, which is more stable than the boat but still much less stable than

1512-440: A typical gasoline consists of a homogeneous mixture of hydrocarbons with between 4 and 12 carbon atoms per molecule (commonly referred to as C4–C12). It is a mixture of paraffins ( alkanes ), olefins ( alkenes ), napthenes ( cycloalkanes ), and aromatics . The use of the term paraffin in place of the standard chemical nomenclature alkane is particular to the oil industry (which relies extensively on jargon). The composition of

SECTION 20

#1732787364907

1584-738: Is 10 percent ethanol, and 98E5, which is 5 percent ethanol. Most gasoline sold in Sweden has 5–15 percent ethanol added. Three different ethanol blends are sold in the Netherlands—E5, E10 and hE15. The last of these differs from standard ethanol–gasoline blends in that it consists of 15 percent hydrous ethanol (i.e., the ethanol–water azeotrope ) instead of the anhydrous ethanol traditionally used for blending with gasoline. The Brazilian National Agency of Petroleum, Natural Gas and Biofuels (ANP) requires gasoline for automobile use to have 27.5 percent of ethanol added to its composition. Pure hydrated ethanol

1656-450: Is a high-volume profitable product produced in crude oil refineries. The fuel-characteristics of a particular gasoline-blend, which will resist igniting too early are measured as the octane rating of the fuel blend. Gasoline blends with stable octane ratings are produced in several fuel-grades for various types of motors. A low octane rated fuel may cause engine knocking and reduced efficiency in reciprocating engines . Tetraethyl lead

1728-456: Is a naturally colorless liquid, many gasolines are dyed in various colors to indicate their composition and acceptable uses. In Australia, the lowest grade of gasoline (RON 91) was dyed a light shade of red/orange, but is now the same color as the medium grade (RON 95) and high octane (RON 98), which are dyed yellow. In the U.S., aviation gasoline ( avgas ) is dyed to identify its octane rating and to distinguish it from kerosene-based jet fuel, which

1800-509: Is also available as a fuel. Legislation requires retailers to label fuels containing ethanol on the dispenser, and limits ethanol use to 10 percent of gasoline in Australia. Such gasoline is commonly called E10 by major brands, and it is cheaper than regular unleaded gasoline. The federal Renewable Fuel Standard (RFS) effectively requires refiners and blenders to blend renewable biofuels (mostly ethanol) with gasoline, sufficient to meet

1872-459: Is called E85 . The most extensive use of ethanol takes place in Brazil , where the ethanol is derived from sugarcane . In 2004, over 13 billion liters (3.4 × 10 ^  U.S. gal) of ethanol was produced in the U.S. for fuel use, mostly from corn and sold as E10. E85 is slowly becoming available in much of the U.S., though many of the relatively few stations vending E85 are not open to

1944-729: Is currently allowed. Its use in the European Union is restricted by Article 8a of the Fuel Quality Directive following its testing under the Protocol for the evaluation of effects of metallic fuel-additives on the emissions performance of vehicles. Gummy, sticky resin deposits result from oxidative degradation of gasoline during long-term storage. These harmful deposits arise from the oxidation of alkenes and other minor components in gasoline (see drying oils ). Improvements in refinery techniques have generally reduced

2016-490: Is higher than gasoline's due to a higher hydrogen -to- carbon ratio. Molecular weights of the species in the representative octane combustion are 114, 32, 44, and 18 for C 8 H 18 , O 2 , CO 2 , and H 2 O, respectively; therefore one kilogram (2.2 lb) of fuel reacts with 3.51 kilograms (7.7 lb) of oxygen to produce 3.09 kilograms (6.8 lb) of carbon dioxide and 1.42 kilograms (3.1 lb) of water. Spark-ignition engines are designed to burn gasoline in

2088-569: Is higher than n-alkanes. In the European Union, the benzene limit is set at one percent by volume for all grades of automotive gasoline. This is usually achieved by avoiding feeding C6, in particular cyclohexane , to the reformer unit, where it would be converted to benzene. Therefore, only (desulfurized) heavy virgin naphtha (HVN) is fed to the reformer unit Gasoline can also contain other organic compounds , such as organic ethers (deliberately added), plus small levels of contaminants, in particular organosulfur compounds (which are usually removed at

2160-420: Is left colorless. In Canada, the gasoline for marine and farm use is dyed red and is not subject to fuel excise tax in most provinces. Oxygenate blending adds oxygen -bearing compounds such as MTBE , ETBE , TAME , TAEE , ethanol , and biobutanol . The presence of these oxygenates reduces the amount of carbon monoxide and unburned fuel in the exhaust. In many areas throughout the U.S., oxygenate blending

2232-501: Is mandated by EPA regulations to reduce smog and other airborne pollutants. For example, in Southern California fuel must contain two percent oxygen by weight, resulting in a mixture of 5.6 percent ethanol in gasoline. The resulting fuel is often known as reformulated gasoline (RFG) or oxygenated gasoline, or, in the case of California, California reformulated gasoline (CARBOB). The federal requirement that RFG contain oxygen

Gasoline - Misplaced Pages Continue

2304-448: Is measured relative to a mixture of 2,2,4-trimethylpentane (an isomer of octane ) and n- heptane . There are different conventions for expressing octane ratings, so the same physical fuel may have several different octane ratings based on the measure used. One of the best known is the research octane number (RON). The octane rating of typical commercially available gasoline varies by country. In Finland , Sweden , and Norway , 95 RON

2376-646: Is produced by hydrogenation of benzene in the presence of a Raney nickel catalyst. Producers of cyclohexane account for approximately 11.4% of global demand for benzene. The reaction is highly exothermic, with ΔH(500 K) = -216.37 kJ/mol. Dehydrogenation commenced noticeably above 300 °C, reflecting the favorable entropy for dehydrogenation. Unlike benzene , cyclohexane is not found in natural resources such as coal. For this reason, early investigators synthesized their cyclohexane samples. Surprisingly, their cyclohexanes boiled higher by 10 °C than either hexahydrobenzene or hexanaphthene, but this riddle

2448-405: Is produced in oil refineries . Roughly 72 liters (19 U.S. gal) of gasoline is derived from a 160-liter (42 U.S. gal) barrel of crude oil . Material separated from crude oil via distillation , called virgin or straight-run gasoline, does not meet specifications for modern engines (particularly the octane rating ; see below), but can be pooled to the gasoline blend. The bulk of

2520-457: Is sporadic or seasonal (little to no use for one or more seasons of the year). Users have been advised to keep gasoline containers more than half full and properly capped to reduce air exposure, to avoid storage at high temperatures, to run an engine for ten minutes to circulate the stabilizer through all components prior to storage, and to run the engine at intervals to purge stale fuel from the carburetor. Gasoline stability requirements are set by

2592-489: Is the alkyl substituent of cyclohexane and is abbreviated Cy . Cyclohexane is one of components of naphtha , from which it can be extracted by advanced distillation methods. Distillation is usually combined with isomerization of methylcyclopentane , a similar component extracted from naphtha by similar methods. Together, these processes cover only a minority (15-20%) of the modern industrial demand, and are complemented by synthesis. On an industrial scale, cyclohexane

2664-490: Is the standard for regular unleaded gasoline and 98 RON is also available as a more expensive option. In the United Kingdom, over 95 percent of gasoline sold has 95 RON and is marketed as Unleaded or Premium Unleaded. Super Unleaded, with 97/98 RON and branded high-performance fuels (e.g., Shell V-Power, BP Ultimate) with 99 RON make up the balance. Gasoline with 102 RON may rarely be available for racing purposes. In

2736-448: The U.S. Clean Air Act banned the sale of leaded fuel for use in on-road vehicles in the U.S. The use of TEL also necessitated other additives, such as dibromoethane . European countries began replacing lead-containing additives by the end of the 1980s, and by the end of the 1990s, leaded gasoline was banned within the entire European Union with an exception for Avgas 100LL for general aviation . The UAE started to switch to unleaded in

2808-642: The United States and Canada . In North America, different English dialects of immigrants from England , Scotland , Ireland , and other regions of the British Isles mixed together in the 17th and 18th centuries. These were developed, built upon, and blended together as new waves of immigration, and migration across the North American continent, developed new dialects in new areas, and as these ways of speaking merged with and assimilated to

2880-477: The Rolls-Royce Merlin 66 was developing 1,500 kilowatts (2,000 hp) using this fuel. Gasoline, when used in high- compression internal combustion engines, tends to auto-ignite or "detonate" causing damaging engine knocking (also called "pinging" or "pinking"). To address this problem, tetraethyl lead (TEL) was widely adopted as an additive for gasoline in the 1920s. With a growing awareness of

2952-691: The U.S., octane ratings in unleaded fuels vary between 85 and 87 AKI (91–92 RON) for regular, 89–90 AKI (94–95 RON) for mid-grade (equivalent to European regular), up to 90–94 AKI (95–99 RON) for premium (European premium). As South Africa's largest city, Johannesburg , is located on the Highveld at 1,753 meters (5,751 ft) above sea level, the Automobile Association of South Africa recommends 95-octane gasoline at low altitude and 93-octane for use in Johannesburg because "The higher

Gasoline - Misplaced Pages Continue

3024-455: The altitude the lower the air pressure, and the lower the need for a high octane fuel as there is no real performance gain". Octane rating became important as the military sought higher output for aircraft engines in the late 1920s and the 1940s. A higher octane rating allows a higher compression ratio or supercharger boost, and thus higher temperatures and pressures, which translate to higher power output. Some scientists even predicted that

3096-586: The announcement "the end of one toxic era". However, leaded gasoline continues to be used in aeronautic, auto racing, and off-road applications. The use of leaded additives is still permitted worldwide for the formulation of some grades of aviation gasoline such as 100LL , because the required octane rating is difficult to reach without the use of leaded additives. Different additives have replaced lead compounds. The most popular additives include aromatic hydrocarbons , ethers ( MTBE and ETBE ), and alcohols , most commonly ethanol . Lead replacement petrol (LRP)

3168-612: The buildup may or may not be eventually cleaned out by the flow of fresh gasoline. The addition of a fuel stabilizer to gasoline can extend the life of fuel that is not or cannot be stored properly, though removal of all fuel from a fuel system is the only real solution to the problem of long-term storage of an engine or a machine or vehicle. Typical fuel stabilizers are proprietary mixtures containing mineral spirits , isopropyl alcohol , 1,2,4-trimethylbenzene or other additives . Fuel stabilizers are commonly used for small engines, such as lawnmower and tractor engines, especially when their use

3240-425: The chair. The chair and twist-boat are energy minima and are therefore conformers, while the half-chair and the boat are transition states and represent energy maxima. The idea that the chair conformation is the most stable structure for cyclohexane was first proposed as early as 1890 by Hermann Sachse, but only gained widespread acceptance much later. The new conformation puts the carbons at an angle of 109.5°. Half of

3312-514: The early 2000s. Reduction in the average lead content of human blood may be a major cause for falling violent crime rates around the world including South Africa. A study found a correlation between leaded gasoline usage and violent crime (see Lead–crime hypothesis ). Other studies found no correlation. In August 2021, the UN Environment Programme announced that leaded petrol had been eradicated worldwide, with Algeria being

3384-461: The effects of heavy cross-border trade and cultural penetration by the American mass media. The list of divergent words becomes longer if considering regional Canadian dialects, especially as spoken in the Atlantic provinces and parts of Vancouver Island where significant pockets of British culture still remain. There are a considerable number of different accents within the regions of both

3456-496: The formation of gummy residues. The metal impurities might arise from the engine itself or as contaminants in the fuel. Gasoline, as delivered at the pump, also contains additives to reduce internal engine carbon buildups, improve combustion and allow easier starting in cold climates. High levels of detergent can be found in Top Tier Detergent Gasolines . The specification for Top Tier Detergent Gasolines

3528-419: The gas) that can withstand the vapor pressure of the gasoline without venting (to prevent the loss of the more volatile fractions) at a stable cool temperature (to reduce the excess pressure from liquid expansion and to reduce the rate of any decomposition reactions). When gasoline is not stored correctly, gums and solids may result, which can corrode system components and accumulate on wet surfaces, resulting in

3600-479: The general public. North American English North American English is the most generalized variety of the English language as spoken in the United States and Canada . Because of their related histories and cultures, plus the similarities between the pronunciations (accents), vocabulary, and grammar of American English and Canadian English , the two spoken varieties are often grouped together under

3672-522: The greater American dialect mixture that solidified by the mid-18th century. Below, several major North American English accents are defined by particular characteristics: A majority of North American English (for example, in contrast to British English) includes phonological features that concern consonants, such as rhoticity (full pronunciation of all /r/ sounds), conditioned T-glottalization (with satin pronounced [ˈsæʔn̩] , not [ˈsætn̩] ), T- and D-flapping (with metal and medal pronounced

SECTION 50

#1732787364907

3744-399: The hydrogens are in the plane of the ring ( equatorial ) while the other half are perpendicular to the plane ( axial ). This conformation allows for the most stable structure of cyclohexane. Another conformation of cyclohexane exists, known as boat conformation , but it interconverts to the slightly more stable chair formation. If cyclohexane is mono-substituted with a large substituent , then

3816-400: The last country to deplete its reserves. UN Secretary-General António Guterres called the eradication of leaded petrol an "international success story". He also added: "Ending the use of leaded petrol will prevent more than one million premature deaths each year from heart disease, strokes and cancer, and it will protect children whose IQs are damaged by exposure to lead". Greenpeace called

3888-515: The last quarter of the 19th century. The fuel for these early engines was a relatively volatile hydrocarbon obtained from coal gas . With a boiling point near 85 °C (185 °F) ( n -octane boils at 125.62 °C (258.12 °F)), it was well-suited for early carburetors (evaporators). The development of a "spray nozzle" carburetor enabled the use of less volatile fuels. Further improvements in engine efficiency were attempted at higher compression ratios , but early attempts were blocked by

3960-406: The older gasoline may be used up. If left undiluted, improper operation will occur and this may include engine damage from misfiring or the lack of proper action of the fuel within a fuel injection system and from an onboard computer attempting to compensate (if applicable to the vehicle). Gasoline should ideally be stored in an airtight container (to prevent oxidation or water vapor mixing in with

4032-537: The phaseout of leaded motor fuels in the United Kingdom, Australia , South Africa , and some other countries. Consumer confusion led to a widespread mistaken preference for LRP rather than unleaded, and LRP was phased out 8 to 10 years after the introduction of unleaded. Leaded gasoline was withdrawn from sale in Britain after 31 December 1999, seven years after EEC regulations signaled the end of production for cars using leaded gasoline in member states. At this stage,

4104-577: The premature explosion of fuel, known as knocking . In 1891, the Shukhov cracking process became the world's first commercial method to break down heavier hydrocarbons in crude oil to increase the percentage of lighter products compared to simple distillation. Commercial gasoline as well as other liquid transportation fuels are complex mixtures of hydrocarbons. The performance specification also varies with season, requiring less volatile blends during summer, in order to minimize evaporative losses. Gasoline

4176-425: The refinery). On average, U.S. petroleum refineries produce about 19 to 20 gallons of gasoline, 11 to 13 gallons of distillate fuel diesel fuel and 3 to 4 gallons of jet fuel from each 42 gallon (152 liters) barrel of crude oil. The product ratio depends upon the processing in an oil refinery and the crude oil assay . The specific gravity of gasoline ranges from 0.71 to 0.77, with higher densities having

4248-607: The same), at least one of the LOT vowel mergers (the LOT – PALM merger is completed among virtually all Americans and the LOT – THOUGHT merger among nearly half, while both are completed among virtually all Canadians), and yod-dropping (with tuesday pronounced /ˈtuzdeɪ/ , not /ˈtjuzdeɪ/ ). The last item is more advanced in American English than Canadian English. Cyclohexane Cyclohexyl ( C 6 H 11 )

4320-454: The same, as [ˈmɛɾɫ̩] ), L-velarization (with filling pronounced [ˈfɪɫɪŋ] , not [ˈfɪlɪŋ] ), as well as features that concern vowel sounds, such as various vowel mergers before /r/ (so that, Mary , marry , and merry are all commonly pronounced the same ), raising of pre-voiceless /aɪ/ (with price and bright using a higher vowel sound than prize and bride ), the weak vowel merger (with affected and effected often pronounced

4392-443: The season and producer by up to 1.75 percent more or less than the average. On average, about 74 liters (20 U.S. gal) of gasoline are available from a barrel of crude oil (about 46 percent by volume), varying with the quality of the crude and the grade of the gasoline. The remainder is products ranging from tar to naphtha . A high-octane-rated fuel, such as liquefied petroleum gas (LPG), has an overall lower power output at

SECTION 60

#1732787364907

4464-701: The seriousness of the extent of environmental and health damage caused by lead compounds, however, and the incompatibility of lead with catalytic converters , governments began to mandate reductions in gasoline lead. In the U.S., the Environmental Protection Agency issued regulations to reduce the lead content of leaded gasoline over a series of annual phases, scheduled to begin in 1973 but delayed by court appeals until 1976. By 1995, leaded fuel accounted for only 0.6 percent of total gasoline sales and under 1,800 metric tons (2,000 short tons; 1,800 long tons) of lead per year. From 1 January 1996,

4536-455: The standard ASTM D4814. This standard describes the various characteristics and requirements of automotive fuels for use over a wide range of operating conditions in ground vehicles equipped with spark-ignition engines. A gasoline-fueled internal combustion engine obtains energy from the combustion of gasoline's various hydrocarbons with oxygen from the ambient air, yielding carbon dioxide and water as exhaust. The combustion of octane ,

4608-401: The substituent will most likely be found attached in an equatorial position, as this is the slightly more stable conformation . Cyclohexane has the lowest angle and torsional strain of all the cycloalkanes; as a result cyclohexane has been deemed a 0 in total ring strain. Cyclohexane has two crystalline phases. The high-temperature phase I, stable between 186 K and the melting point 280 K, is

4680-419: The susceptibility of gasolines to these problems. Previously, catalytically or thermally cracked gasolines were most susceptible to oxidation. The formation of gums is accelerated by copper salts, which can be neutralized by additives called metal deactivators . This degradation can be prevented through the addition of 5–100 ppm of antioxidants , such as phenylenediamines and other amines . Hydrocarbons with

4752-408: The typical 10:1 compression ratio of an engine design optimized for gasoline fuel. An engine tuned for LPG fuel via higher compression ratios (typically 12:1) improves the power output. This is because higher-octane fuels allow for a higher compression ratio without knocking, resulting in a higher cylinder temperature, which improves efficiency . Also, increased mechanical efficiency is created by

4824-507: The varying actual percentage. In parts of the U.S., ethanol is sometimes added to gasoline without an indication that it is a component. In October 2007, the Government of India decided to make five percent ethanol blending (with gasoline) mandatory. Currently, 10 percent ethanol blended product (E10) is being sold in various parts of the country. Ethanol has been found in at least one study to damage catalytic converters. Though gasoline

4896-631: Was developed by four automakers: GM , Honda , Toyota , and BMW . According to the bulletin, the minimal U.S. EPA requirement is not sufficient to keep engines clean. Typical detergents include alkylamines and alkyl phosphates at a level of 50–100 ppm. In the EU, 5 percent ethanol can be added within the common gasoline spec (EN 228). Discussions are ongoing to allow 10 percent blending of ethanol (available in Finnish, French and German gasoline stations). In Finland, most gasoline stations sell 95E10, which

4968-402: Was developed for vehicles designed to run on leaded fuels and incompatible with unleaded fuels. Rather than tetraethyllead, it contains other metals such as potassium compounds or methylcyclopentadienyl manganese tricarbonyl (MMT); these are purported to buffer soft exhaust valves and seats so that they do not suffer recession due to the use of unleaded fuel. LRP was marketed during and after

5040-477: Was dropped on 6 May 2006 because the industry had developed VOC -controlled RFG that did not need additional oxygen. MTBE was phased out in the U.S. due to groundwater contamination and the resulting regulations and lawsuits. Ethanol and, to a lesser extent, ethanol-derived ETBE are common substitutes. A common ethanol-gasoline mix of 10 percent ethanol mixed with gasoline is called gasohol or E10, and an ethanol-gasoline mix of 85 percent ethanol mixed with gasoline

5112-472: Was once widely used to increase the octane rating but are not used in modern automotive gasoline due to the health hazard . Aviation, off-road motor vehicles, and racing car motors still use leaded gasolines. Interest in gasoline-like fuels started with the invention of internal combustion engines suitable for use in transportation applications. The so-called Otto engines were developed in Germany during

5184-460: Was solved in 1895 by Markovnikov, N.M. Kishner , and Nikolay Zelinsky when they reassigned "hexahydrobenzene" and "hexanaphtene" as methylcyclopentane , the result of an unexpected rearrangement reaction . In 1894, Baeyer synthesized cyclohexane starting with a ketonization of pimelic acid followed by multiple reductions: In the same year, E. Haworth and W.H. Perkin Jr. (1860–1929) prepared it via

#906093