2,2,4-Trimethylpentane, also known as isooctane or iso-octane, is an organic compound with the formula (CH3)3CCH2CH(CH3)2. It is one of several isomers of octane (C8H18). This particular isomer is the standard 100 point on the octane rating scale (the zero point is n-heptane). It is an important component of gasoline, frequently used in relatively large proportions (around 10%) to increase the knock resistance of fuel.[2][3]
Strictly speaking, if the standard meaning of ‘iso’ is followed, the name isooctane should be reserved for the isomer 2-methylheptane. However, 2,2,4-trimethylpentane is by far the most important isomer of octane and historically it has been assigned this name.[4]
Engine knocking is an unwanted process that can occur during high compression ratios in internal combustion engines. In 1926 Graham Edgar added different amounts of n-heptane and 2,2,4-trimethylpentane to gasoline, and discovered that the knocking stopped when 2,2,4-trimethylpentane was added. This work was the origin of the octane rating scale.[7] Test motors using 2,2,4-trimethylpentane gave a certain performance that was standardized as 100 octane. The same test motors, run in the same fashion, using heptane, gave a performance which was standardized as 0 octane. All other compounds and blends of compounds then were graded against these two standards and assigned octane numbers.
Safety
In common with all hydrocarbons, 2,2,4-trimethylpentane is flammable.[8]
^"2,2,4-trimethylpentane - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification and Related Records. Retrieved 11 March 2012.
^Werner Dabelstein; Arno Reglitzky; Andrea Schütze; Klaus Reders (2007). "Automotive Fuels". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a16_719.pub2. ISBN978-3527306732.
^Richardson, KA; Wilmer, JL; Smith-Simpson, D; Skopek, TR (February 1986). "Assessment of the genotoxic potential of unleaded gasoline and 2,2,4-trimethylpentane in human lymphoblasts in vitro". Toxicology and Applied Pharmacology. 82 (2): 316–22. doi:10.1016/0041-008x(86)90207-3. PMID 3945956.
^Clayden, Jonathan (2005). Organic chemistry (Reprinted (with corrections). ed.). Oxford [u.a.]: Oxford Univ. Press. pp. 315. ISBN978-0-19-850346-0.
^Bipin V. Vora; Joseph A. Kocal; Paul T. Barger; Robert J. Schmidt; James A. Johnson (2003). "Alkylation". Kirk‐Othmer Encyclopedia of Chemical Technology. doi:10.1002/0471238961.0112112508011313.a01.pub2. ISBN0471238961.
trimethylpentane, other, isomers, octane, octane, isomers, also, known, isooctane, octane, organic, compound, with, formula, 3cch2ch, several, isomers, octane, c8h18, this, particular, isomer, standard, point, octane, rating, scale, zero, point, heptane, impor. For other isomers of octane see Octane Isomers 2 2 4 Trimethylpentane also known as isooctane or iso octane is an organic compound with the formula CH3 3CCH2CH CH3 2 It is one of several isomers of octane C8H18 This particular isomer is the standard 100 point on the octane rating scale the zero point is n heptane It is an important component of gasoline frequently used in relatively large proportions around 10 to increase the knock resistance of fuel 2 3 2 2 4 Trimethylpentane NamesPreferred IUPAC name 2 2 4 Trimethylpentane 1 IdentifiersCAS Number 540 84 1 Y3D model JSmol Interactive imageBeilstein Reference 1696876ChEBI CHEBI 62805 NChEMBL ChEMBL1797261 NChemSpider 10445 YECHA InfoCard 100 007 964EC Number 208 759 1MeSH 2 2 4 trimethylpentanePubChem CID 10907RTECS number SA3320000UNII QAB8F5669O YUN number 1262CompTox Dashboard EPA DTXSID7024370InChI InChI 1S C8H18 c1 7 2 6 8 3 4 5 h7H 6H2 1 5H3 YKey NHTMVDHEPJAVLT UHFFFAOYSA N YSMILES CC C CC C C CPropertiesChemical formula C 8H 18Molar mass 114 232 g mol 1Appearance Colorless liquidOdor petroleum likeDensity 0 692 g cm 3Melting point 107 38 C 161 28 F 165 77 KBoiling point 99 30 C 210 74 F 372 45 Klog P 4 373Vapor pressure 5 5 kPa at 21 C Henry s lawconstant kH 3 0 nmol Pa 1 kg 1UV vis lmax 210 nmMagnetic susceptibility x 98 34 10 6 cm3 molRefractive index nD 1 391ThermochemistryHeat capacity C 242 49 J K 1 mol 1Std molarentropy S 298 328 03 J K 1 mol 1Std enthalpy offormation DfH 298 260 6 to 258 0 kJ mol 1Std enthalpy ofcombustion DcH 298 5462 6 to 5460 0 kJ mol 1HazardsGHS labelling PictogramsSignal word DangerHazard statements H225 H304 H315 H336 H410Precautionary statements P210 P261 P273 P301 P310 P331NFPA 704 fire diamond 130Flash point 12 C 10 F 261 K Autoignitiontemperature 396 C 745 F 669 K Explosive limits 1 1 6 0 Related compoundsRelated alkanes 2 2 Dimethylbutane2 3 DimethylbutaneTriptaneTetramethylbutaneTetraethylmethane2 3 3 Trimethylpentane2 3 4 TrimethylpentaneTetra tert butylmethane2 3 Dimethylhexane2 5 DimethylhexaneExcept where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa N verify what is Y N Infobox references Strictly speaking if the standard meaning of iso is followed the name isooctane should be reserved for the isomer 2 methylheptane However 2 2 4 trimethylpentane is by far the most important isomer of octane and historically it has been assigned this name 4 Contents 1 Production 2 History 3 Safety 4 See also 5 References 6 External linksProduction EditIsooctane is produced on a massive scale in the petroleum industry by alkylation of isobutene with isobutane This process is conducted in alkylation units in the presence of acid catalysts 5 Route to 2 2 4 trimethylpentane from isobutene and isobutane It can also be produced from isobutylene by dimerization using an Amberlyst catalyst to produce a mixture of iso octenes Hydrogenation of this mixture produces 2 2 4 trimethylpentane 6 History EditEngine knocking is an unwanted process that can occur during high compression ratios in internal combustion engines In 1926 Graham Edgar added different amounts of n heptane and 2 2 4 trimethylpentane to gasoline and discovered that the knocking stopped when 2 2 4 trimethylpentane was added This work was the origin of the octane rating scale 7 Test motors using 2 2 4 trimethylpentane gave a certain performance that was standardized as 100 octane The same test motors run in the same fashion using heptane gave a performance which was standardized as 0 octane All other compounds and blends of compounds then were graded against these two standards and assigned octane numbers Safety EditIn common with all hydrocarbons 2 2 4 trimethylpentane is flammable 8 See also EditOil refinery Antiknock agentsReferences Edit 2 2 4 trimethylpentane Compound Summary PubChem Compound USA National Center for Biotechnology Information 26 March 2005 Identification and Related Records Retrieved 11 March 2012 Werner Dabelstein Arno Reglitzky Andrea Schutze Klaus Reders 2007 Automotive Fuels Ullmann s Encyclopedia of Industrial Chemistry Weinheim Wiley VCH doi 10 1002 14356007 a16 719 pub2 ISBN 978 3527306732 Richardson KA Wilmer JL Smith Simpson D Skopek TR February 1986 Assessment of the genotoxic potential of unleaded gasoline and 2 2 4 trimethylpentane in human lymphoblasts in vitro Toxicology and Applied Pharmacology 82 2 316 22 doi 10 1016 0041 008x 86 90207 3 PMID 3945956 Clayden Jonathan 2005 Organic chemistry Reprinted with corrections ed Oxford u a Oxford Univ Press pp 315 ISBN 978 0 19 850346 0 Bipin V Vora Joseph A Kocal Paul T Barger Robert J Schmidt James A Johnson 2003 Alkylation Kirk Othmer Encyclopedia of Chemical Technology doi 10 1002 0471238961 0112112508011313 a01 pub2 ISBN 0471238961 Dimerization of isobutylene Amberlyst com Fuels and lubricants handbook Volume 1 George E Totten Steven R Westbrook Rajesh J Shah page 62 2 2 4 Trimethylpentane Integrated Risk Information System United States Environmental Protection AgencyExternal links Edit Wikimedia Commons has media related to Isooctane International Chemical Safety Card 0496 Retrieved from https en wikipedia org w index php title 2 2 4 Trimethylpentane amp oldid 1099858409, wikipedia, wiki, book, books, library,
