Isobutylene

Last updated
Isobutylene
Isobutylene.svg
Ball-and-stick model of isobutylene Isobutylene-3D-balls.png
Ball-and-stick model of isobutylene
Space-filling model of isobutylene Isobutylene-3D-vdW.png
Space-filling model of isobutylene
Names
Preferred IUPAC name
2-Methylprop-1-ene
Other names
2-Methylpropene
Isobutene
γ-Butylene
2-Methylpropylene
Methylpropene
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.003.697 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 204-066-3
PubChem CID
RTECS number
  • UD0890000
UNII
UN number 1055
In Liquefied petroleum gas: 1075
  • InChI=1S/C4H8/c1-4(2)3/h1H2,2-3H3 Yes check.svgY
    Key: VQTUBCCKSQIDNK-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C4H8/c1-4(2)3/h1H2,2-3H3
  • CC(=C)C
Properties [1]
C4H8
Molar mass 56.106 g/mol
AppearanceColorless gas
Density 0.5879 g/cm3, liquid
Melting point −140.3 °C (−220.5 °F; 132.8 K)
Boiling point −6.9 °C (19.6 °F; 266.2 K)
-44.4·10−6 cm3/mol
Hazards [2]
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-exclam.svg
Danger
H220
P210, P377, P381, P403
NFPA 704 (fire diamond)
NFPA 704.svgHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g. propaneInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
4
0
Flash point flammable gas
465 °C (869 °F; 738 K)
Explosive limits 1.8–9.6%
Related compounds
Related butenes
1-Butene
cis-2-Butene
trans-2-Butene
Related compounds
 Isobutane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Isobutylene (or 2-methylpropene) is a hydrocarbon with the chemical formula (CH3)2C=CH2. It is a four-carbon branched alkene (olefin), one of the four isomers of butylene. It is a colorless flammable gas, and is of considerable industrial value. [3]

Contents

Production

Polymer and chemical grade isobutylene is typically obtained by dehydrating tertiary butyl alcohol (TBA) or catalytic dehydrogenation of isobutane (Catofin or similar processes). [4] Gasoline additives methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE), respectively, are produced by reacting methanol or ethanol with isobutylene contained in butene streams from olefin steam crackers or refineries, or with isobutylene from dehydrated TBA. Isobutylene is not isolated from the olefin or refinery butene stream before the reaction, as separating the ethers from the remaining butenes is simpler. Isobutylene can also be produced in high purities by "back-cracking" MTBE or ETBE at high temperatures and then separating the isobutylene by distillation from methanol.

Isobutylene is a byproduct in the ethenolysis of diisobutene to prepare neohexene: [5]

(CH3)3C-CH=C(CH3)2 + CH2=CH2 → (CH3)3C-CH=CH2 + (CH3)2C=CH2

Uses

Isobutylene is used in the production of a variety of products. It is alkylated with butane to produce isooctane or dimerized to diisobutylene (DIB) and then hydrogenated to make isooctane, a fuel additive. Isobutylene is also used in the production of methacrolein. Polymerization of isobutylene produces butyl rubber (polyisobutylene or PIB). Antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are produced by Friedel-Crafts alkylation of phenols with isobutylene.

tert-Butylamine is produced commercially by amination of isobutylene using zeolite catalysts: [6]

NH3 + CH2=C(CH3)2 → H2NC(CH3)3

Applications are found in the calibration of photoionization detectors.

Safety

Isobutylene is a highly flammable gas.

See also

Related Research Articles

<span class="mw-page-title-main">Ether</span> Organic compounds made of alkyl/aryl groups bound to oxygen (R–O–R)

In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom bonded to two organyl groups. They have the general formula R−O−R′, where R and R′ represent the organyl groups. Ethers can again be classified into two varieties: if the organyl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether". Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin.

<span class="mw-page-title-main">Ester</span> Compound derived from an acid

In chemistry, an ester is a functional group derived from an acid in which the hydrogen atom (H) of at least one acidic hydroxyl group of that acid is replaced by an organyl group. Analogues derived from oxygen replaced by other chalcogens belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well, but not according to the IUPAC.

<span class="mw-page-title-main">Tetrahydrofuran</span> Cyclic chemical compound, (CH₂)₄O

Tetrahydrofuran (THF), or oxolane, is an organic compound with the formula (CH2)4O. The compound is classified as heterocyclic compound, specifically a cyclic ether. It is a colorless, water-miscible organic liquid with low viscosity. It is mainly used as a precursor to polymers. Being polar and having a wide liquid range, THF is a versatile solvent. It is an isomer of another solvent, butanone.

Methyl <i>tert</i>-butyl ether Chemical compound

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.

Ethyl <i>tert</i>-butyl ether Oxygenate gasoline additive in the production of gasoline from crude oil

Ethyl tertiary-butyl ether (ETBE), also known as ethyl tert-butyl ether, is commonly used as an oxygenate gasoline additive in the production of gasoline from crude oil. ETBE offers equal or greater air quality benefits than ethanol, while being technically and logistically less challenging. Unlike ethanol, ETBE does not induce evaporation of gasoline, which is one of the causes of smog, and does not absorb moisture from the atmosphere.

<span class="mw-page-title-main">Methyl methacrylate</span> Organic monomer

Methyl methacrylate (MMA) is an organic compound with the formula CH2=C(CH3)COOCH3. This colorless liquid, the methyl ester of methacrylic acid (MAA), is a monomer produced on a large scale for the production of poly(methyl methacrylate) (PMMA).

<i>tert</i>-Butyl alcohol Chemical compound

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.

<span class="mw-page-title-main">1-Butene</span> Chemical compound

1-Butene (IUPAC name: But-1-ene, also known as 1-butylene) is the organic compound with the formula CH3CH2CH=CH2. It is a colorless gas. But-1-ene is an alkene easily condensed to give a colorless liquid. It is classified as a linear alpha-olefin (terminal alkene). It is one of the isomers of butene (butylene). It is a precursor to diverse products.

<span class="mw-page-title-main">Hydroperoxide</span> Class of chemical compounds

Hydroperoxides or peroxols are compounds of the form ROOH, where R stands for any group, typically organic, which contain the hydroperoxy functional group. Hydroperoxide also refers to the hydroperoxide anion and its salts, and the neutral hydroperoxyl radical (•OOH) consist of an unbond hydroperoxy group. When R is organic, the compounds are called organic hydroperoxides. Such compounds are a subset of organic peroxides, which have the formula ROOR. Organic hydroperoxides can either intentionally or unintentionally initiate explosive polymerisation in materials with unsaturated chemical bonds.

2,4-Dimethyl-6-<i>tert</i>-butylphenol Chemical compound

2,4-Dimethyl-6-tert-butylphenol is the organic compound with the formula Me2(tert-Bu)C6H2OH (Me = methyl, tert-Bu = tertiary butyl). It is a colorless oil that is classified as an alkylated phenol.

2,6-Di-<i>tert</i>-butylphenol Chemical compound

2,6-Di-tert-butylphenol is an organic compound with the structural formula 2,6-((CH3)3C)2C6H3OH. This colorless solid alkylated phenol and its derivatives are used industrially as UV stabilizers and antioxidants for hydrocarbon-based products ranging from petrochemicals to plastics. Illustrative of its usefulness, it prevents gumming in aviation fuels.

<span class="mw-page-title-main">Methacrylic acid</span> Chemical compound

Methacrylic acid, abbreviated MAA, is an organic compound with the formula CH2=C(CH3)CO2H. This colorless, viscous liquid is a carboxylic acid with an acrid unpleasant odor. It is soluble in warm water and miscible with most organic solvents. Methacrylic acid is produced industrially on a large scale as a precursor to its esters, especially methyl methacrylate (MMA), and to poly(methyl methacrylate) (PMMA).

tert-Butyl chloride is the organochloride with the formula (CH3)3CCl. It is a colorless, flammable liquid. It is sparingly soluble in water, with a tendency to undergo hydrolysis to the corresponding tert-butyl alcohol. It is produced industrially as a precursor to other organic compounds.

<i>tert</i>-Butylamine Chemical compound

tert-Butylamine (also erbumine and other names) is an organic chemical compound with the formula (CH3)3CNH2. It is a colorless liquid with a typical amine-like odor. tert-Butylamine is one of the four isomeric amines of butane, the others being n-butylamine, sec-butylamine and isobutylamine.

Isopropyl chloride is an organic compound with the chemical formula (CH3)2CHCl. It is a colourless to slightly yellow, volatile, flammable liquid with a sweet, ether-like (almost like petroleum) odour. It is used as an industrial solvent.

<i>tert</i>-Butyl hydroperoxide Chemical compound

tert-Butyl hydroperoxide (tBuOOH) is the organic compound with the formula (CH3)3COOH. It is one of the most widely used hydroperoxides in a variety of oxidation processes, like the Halcon process. It is normally supplied as a 69–70% aqueous solution. Compared to hydrogen peroxide and organic peracids, tert-butyl hydroperoxide is less reactive and more soluble in organic solvents. Overall, it is renowned for the convenient handling properties of its solutions. Its solutions in organic solvents are highly stable.

<span class="mw-page-title-main">Triisobutylaluminium</span> Chemical compound

Triisobutylaluminium (TiBA) is an organoaluminium compound with the formula Al(CH2CH(CH3)2)3. This colorless pyrophoric liquid is mainly used to make linear primary alcohols and α-olefins.

<span class="mw-page-title-main">2-Vinylpyridine</span> Chemical compound

2-Vinylpyridine is an organic compound with the formula CH2CHC5H4N. It is a derivative of pyridine with a vinyl group in the 2-position, next to the nitrogen. It is a colorless liquid, although samples are often brown. It is used industrially as a precursor to specialty polymers and as an intermediate in the chemical, pharmaceutical, dye, and photo industries. Vinylpyridine is sensitive to polymerization. It may be stabilized with a polymerisation inhibitor such as tert-butylcatechol. Owing to its tendency to polymerize, samples are typically refrigerated.

Hydroalkoxylation is a chemical reaction that combines alcohols with alkenes or alkynes. The process affords ethers.

References

  1. ↑ The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals (11th ed.), Merck, 1989, ISBN   091191028X ,5024.
  2. ↑ Isobutene, International Chemical Safety Card 1027, Geneva: International Programme on Chemical Safety, April 2000
  3. ↑ Geilen, Frank M.A.; Stochniol, Guido; Peitz, Stephan; Schulte-Koerne, Ekkehard (2014). "Butenes". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a04_483.pub3. ISBN   978-3527306732.
  4. ↑ Olah, George A.; Molnár, Árpád (May 2003), Hydrocarbon Chemistry, Wiley-Interscience, ISBN   978-0-471-41782-8 .
  5. ↑ Lionel Delaude; Alfred F. Noels. "Metathesis". Kirk-Othmer Encyclopedia of Chemical Technology. Wiley.
  6. ↑ Eller, Karsten; Henkes, Erhard; Rossbacher, Roland; Höke, Hartmut (2000). "Amines, Aliphatic". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a02_001. ISBN   3527306730.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.