Names | |||
---|---|---|---|
Preferred IUPAC name Methylcyclohexane | |||
Other names Hexahydrotoluene Cyclohexylmethane Toluene hexahydride | |||
Identifiers | |||
3D model (JSmol) | |||
ChEBI | |||
ChemSpider | |||
ECHA InfoCard | 100.003.296 | ||
PubChem CID | |||
UNII | |||
CompTox Dashboard (EPA) | |||
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Properties | |||
C7H14 | |||
Molar mass | 98.189 g·mol−1 | ||
Appearance | Colourless liquid | ||
Odor | faint, benzene-like [1] | ||
Density | 0.77 g/cm3 | ||
Melting point | −126.3 °C (−195.3 °F; 146.8 K) | ||
Boiling point | 101 °C (214 °F; 374 K) | ||
0.014 g/L at 25 °C [2] | |||
Vapor pressure | 37 mmHg (20°C) [1] 49.3 hPa at 20.0 °C | ||
-78.91·10−6 cm3/mol | |||
Hazards | |||
Occupational safety and health (OHS/OSH): | |||
Main hazards | severe fire hazard | ||
GHS labelling: | |||
Danger | |||
H225, H302, H304, H315, H336, H410 [2] | |||
P210, P235, P301+P310, P331, P370+P378, P403 [2] | |||
NFPA 704 (fire diamond) | |||
Flash point | −4 °C (25 °F; 269 K) [2] Closed cup | ||
283 °C (541 °F; 556 K) [2] | |||
Explosive limits | 1.2%-6.7% [1] [2] | ||
Lethal dose or concentration (LD, LC): | |||
LD50 (median dose) | 2250 mg/kg (mouse, oral) [3] | ||
LC50 (median concentration) | 10172 ppm (mouse, 2 hr) 10,000-12,500 ppm (mouse, 2 hr) 15227 ppm (rabbit, 1 hr) [3] | ||
NIOSH (US health exposure limits): | |||
PEL (Permissible) | TWA 500 ppm (2000 mg/m3) [1] | ||
REL (Recommended) | TWA 400 ppm (1600 mg/m3) [1] | ||
IDLH (Immediate danger) | 1200 ppm [1] | ||
Safety data sheet (SDS) | [2] | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Methylcyclohexane (cyclohexylmethane) is an organic compound with the molecular formula is CH3C6H11. Classified as saturated hydrocarbon, it is a colourless liquid with a faint odor.
Methylcyclohexane is used as a solvent. It is mainly converted in naphtha reformers to toluene. [4] A special use is in PF-1 priming fluid in cruise missiles to aid engine start-up when they run on special nonvolatile jet fuel like JP-10. [5] Methylcyclohexane is also used in some correction fluids (such as White-Out) as a solvent.
While researching hydrogenation of arenes with hydroiodic acid in 1876 [6] as part of his doctoral dissertation, [7] Felix Wreden first prepared the hydrocarbon from toluene. He determined its boiling point to be 97°C, its density at 20°C to by 0.76 g/cc and named it hexahydrotoluene. [8] It was soon identified in oil from Baku and obtained by other synthetic methods. [9]
Most methylcyclohexane is extracted from petroleum but it can be also produced by catalytic hydrogenation of toluene:
The hydrocarbon is a minor component of automobile fuel, with its share in US gasoline varying between 0.3 and 1.7% in early 1990s [10] and 0.1 to 1% in 2011. [11] Its research and motor octane numbers are 75 and 71 respectively. [12]
As a component of a mixture, it is usually dehydrogenated to toluene, which increases the octane rating of gasoline. [4]
It is also one of a host of substances in jet fuel surrogate blends, e.g., for Jet A fuel. [14] [15]
Methylcyclohexane is used as an organic solvent, with properties similar to related saturated hydrocarbons such as heptane. [16] It is also a solvent in many types of correction fluids.
Methylcyclohexane is a monosubstituted cyclohexane because it has one branching via the attachment of one methyl group on one carbon of the cyclohexane ring. Like all cyclohexanes, it can interconvert rapidly between two chair conformers. The lowest energy form of this monosubstituted methylcyclohexane occurs when the methyl group occupies an equatorial rather than an axial position. This equilibrium is embodied in the concept of A value. In the axial position, the methyl group experiences steric crowding (steric strain) because of the presence of axial hydrogen atoms on the same side of the ring (known as the 1,3-diaxial interactions). There are two such interactions, with each pairwise methyl/hydrogen combination contributing approximately 7.61 kJ/mol of strain energy. The equatorial conformation experiences no such interaction, and so it is the energetically favored conformation.
Methylcyclohexane is flammable.
Furthermore, it is considered "very toxic to aquatic life". [17] Note, while methylcyclohexane is a substructure of 4-methylcyclohexanemethanol (MCHM), it is distinct in its physical, chemical, and biological (ecologic, metabolic, and toxicologic) properties. [18]
Gasoline or petrol 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 is a high-volume profitable product produced in crude oil refineries.
Toluene, also known as toluol, is a substituted aromatic hydrocarbon with the chemical formula C6H5CH3, often abbreviated as PhCH3, where Ph stands for the phenyl group. It is a colorless, water-insoluble liquid with the odor associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) attached to a phenyl group by a single bond. As such, its systematic IUPAC name is methylbenzene. Toluene is predominantly used as an industrial feedstock and a solvent.
Hexane or n-hexane is an organic compound, a straight-chain alkane with six carbon atoms and the molecular formula C6H14.
Naphtha is a flammable liquid hydrocarbon mixture. Generally, it is a fraction of crude oil, but it can also be produced from natural-gas condensates, petroleum distillates, and the fractional distillation of coal tar and peat. In some industries and regions, the name naphtha refers to crude oil or refined petroleum products such as kerosene or diesel fuel.
Cyclohexane is a cycloalkane with the molecular formula C6H12. Cyclohexane is non-polar. Cyclohexane is a colourless, flammable liquid with a distinctive detergent-like odor, reminiscent of cleaning products. Cyclohexane is mainly used for the industrial production of adipic acid and caprolactam, which are precursors to nylon.
Methyl tert-butyl ether (MTBE), also known as tert-butyl methyl ether, is an organic compound with a structural formula (CH3)3COCH3. MTBE is a volatile, flammable, and colorless liquid that is sparingly soluble in water. Primarily used as a fuel additive, MTBE is blended into gasoline to increase its octane rating and knock resistance, and reduce unwanted emissions.
Natural-gas condensate, also called natural gas liquids, is a low-density mixture of hydrocarbon liquids that are present as gaseous components in the raw natural gas produced from many natural gas fields. Some gas species within the raw natural gas will condense to a liquid state if the temperature is reduced to below the hydrocarbon dew point temperature at a set pressure.
Liquid fuels are combustible or energy-generating molecules that can be harnessed to create mechanical energy, usually producing kinetic energy; they also must take the shape of their container. It is the fumes of liquid fuels that are flammable instead of the fluid. Most liquid fuels in widespread use are derived from fossil fuels; however, there are several types, such as hydrogen fuel, ethanol, and biodiesel, which are also categorized as a liquid fuel. Many liquid fuels play a primary role in transportation and the economy.
Cyclopentane (also called C pentane) is a highly flammable alicyclic hydrocarbon with chemical formula C5H10 and CAS number 287-92-3, consisting of a ring of five carbon atoms each bonded with two hydrogen atoms above and below the plane. It is a colorless liquid with a petrol-like odor. Its freezing point is −94 °C and its boiling point is 49 °C. Cyclopentane is in the class of cycloalkanes, being alkanes that have one or more carbon rings. It is formed by cracking cyclohexane in the presence of alumina at a high temperature and pressure.
Cyclohexane conformations are any of several three-dimensional shapes adopted by cyclohexane. Because many compounds feature structurally similar six-membered rings, the structure and dynamics of cyclohexane are important prototypes of a wide range of compounds.
Catalytic reforming is a chemical process used to convert naphthas from crude oil into liquid products called reformates, which are premium "blending stocks" for high-octane gasoline. The process converts low-octane linear hydrocarbons (paraffins) into branched alkanes (isoparaffins) and cyclic naphthenes, which are then partially dehydrogenated to produce high-octane aromatic hydrocarbons. The dehydrogenation also produces significant amounts of byproduct hydrogen gas, which is fed into other refinery processes such as hydrocracking. A side reaction is hydrogenolysis, which produces light hydrocarbons of lower value, such as methane, ethane, propane and butanes.
Decalin, a bicyclic organic compound, is an industrial solvent. A colorless liquid with an aromatic odor, it is used as a solvent for many resins or fuel additives.
tert-Butyl alcohol is the simplest tertiary alcohol, with a formula of (CH3)3COH (sometimes represented as t-BuOH). Its isomers are 1-butanol, isobutanol, and butan-2-ol. tert-Butyl alcohol is a colorless solid, which melts near room temperature and has a camphor-like odor. It is miscible with water, ethanol and diethyl ether.
1,2,4-Trimethylbenzene, also known as pseudocumene, is an organic compound with the chemical formula C6H3(CH3)3. Classified as an aromatic hydrocarbon, it is a flammable colorless liquid with a strong odor. It is nearly insoluble in water but soluble in organic solvents. It occurs naturally in coal tar and petroleum (about 3%). It is one of the three isomers of trimethylbenzene.
An antiknock agent is a gasoline additive used to reduce engine knocking and increase the fuel's octane rating by raising the temperature and pressure at which auto-ignition occurs. The mixture known as gasoline or petrol, when used in high compression internal combustion engines, has a tendency to knock and/or to ignite early before the correctly timed spark occurs.
3-Methylpentane is a branched alkane with the molecular formula C6H14. It is a structural isomer of hexane composed of a methyl group bonded to the third carbon atom in a pentane chain. It is of similar structure to the isomeric 2-methylpentane, which has the methyl group located on the second carbon of the pentane chain.
Butane is an alkane with the formula C4H10. Butane exists as two isomers, n-butane with connectivity CH3CH2CH2CH3 and iso-butane with the formula (CH3)3CH. Both isomers are highly flammable, colorless, easily liquefied gases that quickly vaporize at room temperature and pressure. Butanes are a trace components of natural gases (NG gases). The other hydrocarbons in NG include propane, ethane, and especially methane, which are more abundant. Liquefied petroleum gas is a mixture of propane and some butanes.
Petroleum naphtha is an intermediate hydrocarbon liquid stream derived from the refining of crude oil with CAS-no 64742-48-9. It is most usually desulfurized and then catalytically reformed, which rearranges or restructures the hydrocarbon molecules in the naphtha as well as breaking some of the molecules into smaller molecules to produce a high-octane component of gasoline.
Fuel surrogates are mixtures of one or more simple fuels that are designed to emulate either the physical properties or combustion properties of a more complex fuel. While surrogate mixtures can demonstrate more than one characteristic of the desired fuel, more often than not different components are required in order to emulate the wide variety of properties that are of interest to researchers. Jet fuel is an example of a fuel requiring a surrogate for experimental research and numerical modelling due to its complexity and high content variability from one batch to the next. Neat hydrocarbon jet fuel surrogate components include decane, dodecane, methylcyclohexane, and toluene. Gasoline surrogate components include n-heptane and iso-octane. Hexadecane is a diesel surrogate component. Biodiesel surrogate components include methyl butyrate and methyl decanoate.