Mesitylene

Last updated
Mesitylene
Mesitylene 1,3,5-Trimethylbenzene.svg
Mesitylene
Mesitylene Mesitylene-3D-vdW.png
Mesitylene
Names
Preferred IUPAC name
1,3,5-Trimethylbenzene [1]
Other names
Mesitylene [1]
sym-Trimethylbenzene
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.003.278 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 203-604-4
KEGG
PubChem CID
UNII
UN number 2325
  • InChI=1S/C9H12/c1-7-4-8(2)6-9(3)5-7/h4-6H,1-3H3 Yes check.svgY
    Key: AUHZEENZYGFFBQ-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C9H12/c1-7-4-8(2)6-9(3)5-7/h4-6H,1-3H3
    Key: AUHZEENZYGFFBQ-UHFFFAOYAK
  • Cc1cc(cc(c1)C)C
Properties
C9H12
Molar mass 120.19 g/mol
AppearanceColorless liquid [2]
Odor Distinctive, aromatic [2]
Density 0.8637 g/cm3 at 20 °C
Melting point −44.8 °C (−48.6 °F; 228.3 K)
Boiling point 164.7 °C (328.5 °F; 437.8 K)
0.002% (20°C) [2]
Vapor pressure 2 mmHg (20°C) [2]
-92.32·10−6 cm3/mol
Structure
0.047 D [3]
Hazards
Flash point 50 °C; 122 °F; 323 K [2]
NIOSH (US health exposure limits):
PEL (Permissible)
none [2]
REL (Recommended)
TWA 25 ppm (125 mg/m3) [2]
IDLH (Immediate danger)
N.D. [2]
Safety data sheet (SDS)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Mesitylene or 1,3,5-trimethylbenzene is a derivative of benzene with three methyl substituents positioned symmetrically around the ring. The other two isomeric trimethylbenzenes are 1,2,4-trimethylbenzene (pseudocumene) and 1,2,3-trimethylbenzene (hemimellitene). All three compounds have the formula C6H3(CH3)3, which is commonly abbreviated C6H3Me3. Mesitylene is a colorless liquid with sweet aromatic odor. It is a component of coal tar, which is its traditional source. It is a precursor to diverse fine chemicals. The mesityl group (Mes) is a substituent with the formula C6H2Me3 and is found in various other compounds. [4]

Contents

Preparation

Mesitylene is prepared by transalkylation of xylene over solid acid catalyst: [4]

2  C6H4(CH3)2  ⇌ C6H3(CH3)3 +  C6H5CH3
C6H4(CH3)2 + CH3OH → C6H3(CH3)3 + H2O

Although impractical, it could be prepared by trimerization of propyne, also requiring an acid catalyst, yields a mixture of 1,3,5- and 1,2,4-trimethylbenzenes.

Trimerization of acetone via aldol condensation, which is catalyzed and dehydrated by sulfuric acid is another method of synthesizing mesitylene. [5]

Reactions

Oxidation of mesitylene with nitric acid yields trimesic acid, C6H3(COOH)3. Using manganese dioxide, a milder oxidising agent, 3,5-dimethylbenzaldehyde is formed. Mesitylene is oxidised by trifluoroperacetic acid to produce mesitol (2,4,6-trimethylphenol). [6] Bromination occurs readily, giving mesityl bromide: [7]

(CH3)3C6H3 + Br2 → (CH3)3C6H2Br + HBr

Mesitylene is a ligand in organometallic chemistry, one example being the organomolybdenum complex [(η6-C6H3Me3)Mo(CO)3] [8] which can be prepared from molybdenum hexacarbonyl.

Applications

Mesitylene is mainly used as a precursor to 2,4,6-trimethylaniline, a precursor to colorants. This derivative is prepared by selective mononitration of mesitylene, avoiding oxidation of the methyl groups. [9]

Niche uses

Structure of (mesitylene)molybdenum tricarbonyl, [(e -C6H3Me3)Mo(CO)3] (Mesitylene)molybdenum tricarbonyl.png
Structure of (mesitylene)molybdenum tricarbonyl, [(η -C6H3Me3)Mo(CO)3]

Mesitylene is used in the laboratory as a specialty solvent. In the electronics industry, mesitylene has been used as a developer for photopatternable silicones due to its solvent properties.

The three aromatic hydrogen atoms of mesitylene are in identical chemical shift environments. Therefore, they only give a single peak near 6.8 ppm in the 1H NMR spectrum; the same is also true for the nine methyl protons, which give a singlet near 2.3 ppm. For this reason, mesitylene is sometimes used as an internal standard in NMR samples that contain aromatic protons. [10]

Uvitic acid is obtained by oxidizing mesitylene or by condensing pyruvic acid with baryta water. [11]

The Gattermann reaction can be simplified by replacing the HCN/AlCl3 combination with zinc cyanide (Zn(CN)2). [12] Although it is highly toxic, Zn(CN)2 is a solid, making it safer to work with than gaseous hydrogen cyanide (HCN). [13] The Zn(CN)2 reacts with the HCl to form the key HCN reactant and ZnCl2 that serves as the Lewis-acid catalyst in-situ. An example of the Zn(CN)2 method is the synthesis of mesitaldehyde from mesitylene. [14]

History

Mesitylene was first prepared in 1837 by Robert Kane, an Irish chemist, by heating acetone with concentrated sulfuric acid. [15] He named his new substance "mesitylene" because the German chemist Carl Reichenbach had named acetone "mesit" (from the Greek μεσίτης, the mediator), [16] and Kane believed that his reaction had dehydrated mesit, converting it to an alkene, "mesitylene". [17] However, Kane's determination of the chemical composition ("empirical formula") of mesitylene was incorrect. The correct empirical formula was provided by August W. von Hofmann in 1849. [18] In 1866 Adolf von Baeyer gave a correct mesitylene's empirical formula; however, with a wrong structure of tetracyclo[3.1.1.11,3.13,5]nonane. [19] A conclusive proof that mesitylene was trimethylbenzene was provided by Albert Ladenburg in 1874; however, assuming wrong benzene structure of prismane. [20]

Mesityl group

The group (CH3)3C6H2- is called mesityl (organic group symbol: Mes). Mesityl derivatives, e.g. tetramesityldiiron, are typically prepared from the Grignard reagent (CH3)3C6H2MgBr. [21] Due to its large steric demand, the mesityl group is used as a large blocking group in asymmetric catalysis (to enhance diastereo- or enantioselectivity) and organometallic chemistry (to stabilize low oxidation state or low coordination number metal centers). Larger analogues with even greater steric demand, for example 2,6-diisopropylphenyl (Dipp) and the analogously named Tripp ((iPr)3C6H2, Is) and supermesityl ((tBu)3C6H2, Mes*) groups, may be even more effective toward achieving these goals.

Safety and the environment

Mesitylene is also a major urban volatile organic compound (VOC) which results from combustion. It plays a significant role in aerosol and tropospheric ozone formation as well as other reactions in atmospheric chemistry.[ citation needed ]

Related Research Articles

<span class="mw-page-title-main">Ketone</span> Organic compounds of the form >C=O

In organic chemistry, a ketone is an organic compound with the structure R−C(=O)−R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group −C(=O)−. The simplest ketone is acetone, with the formula (CH3)2CO. Many ketones are of great importance in biology and industry. Examples include many sugars (ketoses), many steroids, and the solvent acetone.

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

N,N-Dimethylaniline (DMA) is an organic chemical compound, a substituted derivative of aniline. It is a tertiary amine, featuring a dimethylamino group attached to a phenyl group. This oily liquid is colourless when pure, but commercial samples are often yellow. It is an important precursor to dyes such as crystal violet.

Furan is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen atom. Chemical compounds containing such rings are also referred to as furans.

<span class="mw-page-title-main">Cyanohydrin</span> Functional group in organic chemistry

In organic chemistry, a cyanohydrin or hydroxynitrile is a functional group found in organic compounds in which a cyano and a hydroxy group are attached to the same carbon atom. The general formula is R2C(OH)CN, where R is H, alkyl, or aryl. Cyanohydrins are industrially important precursors to carboxylic acids and some amino acids. Cyanohydrins can be formed by the cyanohydrin reaction, which involves treating a ketone or an aldehyde with hydrogen cyanide (HCN) in the presence of excess amounts of sodium cyanide (NaCN) as a catalyst:

<span class="mw-page-title-main">Anisole</span> Organic compound (CH₃OC₆H₅) also named methoxybenzene

Anisole, or methoxybenzene, is an organic compound with the formula CH3OC6H5. It is a colorless liquid with a smell reminiscent of anise seed, and in fact many of its derivatives are found in natural and artificial fragrances. The compound is mainly made synthetically and is a precursor to other synthetic compounds. Structurally, it is an ether with a methyl and phenyl group attached. Anisole is a standard reagent of both practical and pedagogical value.

<span class="mw-page-title-main">Acetone</span> Organic compound ((CH3)2CO); simplest ketone

Acetone is an organic compound with the formula (CH3)2CO. It is the simplest and smallest ketone. It is a colorless, highly volatile, and flammable liquid with a characteristic pungent odour, very reminiscent of the smell of pear drops.

<span class="mw-page-title-main">Methyl isobutyl ketone</span> Chemical compound

Methyl isobutyl ketone (MIBK, 4-methylpentan-2-one) is an organic compound with the condensed chemical formula (CH3)2CHCH2C(O)CH3. This ketone is a colourless liquid that is used as a solvent for gums, resins, paints, varnishes, lacquers, and nitrocellulose.

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

Mesityl oxide is a α,β-unsaturated ketone with the formula CH3C(O)CH=C(CH3)2. This compound is a colorless, volatile liquid with a honey-like odor.

<span class="mw-page-title-main">Aleksandr Dianin</span> Russian chemist (1851–1918)

Aleksandr Pavlovich Dianin was a Russian chemist from Saint Petersburg. He carried out studies on phenols and discovered a phenol derivative now known as bisphenol A and the accordingly named Dianin's compound. He was married to the adopted daughter of fellow chemist Alexander Borodin. In 1887, Dianin succeeded his father-in-law as chair of the Chemistry Department at the Imperial Medical-Surgical Academy in St. Petersburg.

1,3,5-Triazine, also called s-triazine, is an organic chemical compound with the formula (HCN)3. It is a six-membered heterocyclic aromatic ring, one of several isomeric triazines. s-Triazine —the "symmetric" isomer—and its derivatives are useful in a variety of applications.

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.

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

Zinc cyanide is the inorganic compound with the formula Zn(CN)2. It is a white solid that is used mainly for electroplating zinc but also has more specialized applications for the synthesis of organic compounds.

<span class="mw-page-title-main">Organotitanium chemistry</span>

Organotitanium chemistry is the science of organotitanium compounds describing their physical properties, synthesis, and reactions. Organotitanium compounds in organometallic chemistry contain carbon-titanium chemical bonds. They are reagents in organic chemistry and are involved in major industrial processes.

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

Diacetone alcohol is an organic compound with the formula CH3C(O)CH2C(OH)(CH3)2, sometimes called DAA. This colorless liquid is a common synthetic intermediate used for the preparation of other compounds, and is also used as a solvent.

Acetone cyanohydrin (ACH) is an organic compound used in the production of methyl methacrylate, the monomer of the transparent plastic polymethyl methacrylate (PMMA), also known as acrylic. It liberates hydrogen cyanide easily, so it is used as a source of such. For this reason, this cyanohydrin is also highly toxic.

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

Durene, or 1,2,4,5-tetramethylbenzene, is an organic compound with the formula C6H2(CH3)4. It is a colourless solid with a sweet odor. The compound is classified as an alkylbenzene. It is one of three isomers of tetramethylbenzene, the other two being prehnitene (1,2,3,4-tetramethylbenzene) and isodurene (1,2,3,5-tetramethylbenzene). Durene has an unusually high melting point (79.2 °C), reflecting its high molecular symmetry.

<span class="mw-page-title-main">1,3,5-Trinitrobenzene</span> Chemical compound

1,3,5-Trinitrobenzene is one of three isomers of trinitrobenzene with the formula C6H3(NO2)3. A pale yellow solid, the compound is highly explosive.

<span class="mw-page-title-main">(Mesitylene)molybdenum tricarbonyl</span> Chemical compound

(Mesitylene)molybdenum tricarbonyl is an organomolybdenum compound derived from the aromatic compound mesitylene (1,3,5-trimethylbenzene) and molybdenum carbonyl. It exists as pale yellow crystals, which are soluble in organic solvents but decompose when in solution. It has been examined as a catalyst and reagent.

<span class="mw-page-title-main">Isodurene</span> Organic compound

Isodurene or 1,2,3,5-tetramethylbenzene is an organic compound with the formula C6H2(CH3)4, classified as an aromatic hydrocarbon. It is a flammable colorless liquid which is nearly insoluble in water but soluble in organic solvents. It occurs naturally in coal tar. Isodurene is one of three isomers of tetramethylbenzene, the other two being prehnitene (1,2,3,4-tetramethylbenzene) and durene (1,2,4,5-tetramethylbenzene).

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

Mesityl bromide is an organic compound with the formula (CH3)3C6H2Br. It is a derivative of mesitylene (1,3,5-trimethylbenzene) with one ring H replaced by Br. The compound is a colorless oil. It is a standard electron-rich aryl halide substrate for cross coupling reactions. With magnesium it reacts to give the Grignard reagent, which is used in the preparation of tetramesityldiiron.

References

  1. 1 2 Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 139. doi:10.1039/9781849733069-FP001. ISBN   978-0-85404-182-4.
  2. 1 2 3 4 5 6 7 8 NIOSH Pocket Guide to Chemical Hazards. "#0639". National Institute for Occupational Safety and Health (NIOSH).
  3. ↑ Zhao, Jun; Zhang, Renyi (2004). "Proton transfer reaction rate constants between hydronium ion (H3O+) and volatile organic compounds". Atmospheric Environment. 38 (14): 2177–2185. Bibcode:2004AtmEn..38.2177Z. doi:10.1016/j.atmosenv.2004.01.019.
  4. 1 2 Karl Griesbaum, Arno Behr, Dieter Biedenkapp, Heinz-Werner Voges, Dorothea Garbe, Christian Paetz, Gerd Collin, Dieter Mayer, Hartmut Höke “Hydrocarbons” in Ullmann's Encyclopedia of Industrial Chemistry 2002 Wiley-VCH, Weinheim. doi : 10.1002/14356007.a13_227.
  5. ↑ Cumming, W. M. (1937). Systematic organic chemistry (3E). New York, USA: D. Van Nostrand Company. p. 57.
  6. ↑ Chambers, Richard D. (2004). "Functional Compounds Containing Oxygen, Sulphur or Nitrogen and their Derivatives". Fluorine in Organic Chemistry. CRC Press. pp. 242–243. ISBN   9780849317903.
  7. ↑ Lee Irvin Smith (1931). "Bromomesitylene". Org. Synth. 11: 24. doi:10.15227/orgsyn.011.0024.
  8. ↑ Girolami, G. S.; Rauchfuss, T. B. and Angelici, R. J.  [ de ], Synthesis and Technique in Inorganic Chemistry, University Science Books: Mill Valley, CA, 1999. ISBN   0-93570248-2.
  9. ↑ Gerald Booth (2007). "Nitro Compounds, Aromatic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a17_411. ISBN   978-3527306732.
  10. ↑ "Mesitylene (1,3,5-Trimethyl Benzene)".
  11. ↑ "Definition of uvitic acid". merriam-webster.com. Retrieved 31 October 2016.
  12. ↑ Adams R.; Levine, I. (1923). "Simplification of the Gattermann Synthesis of Hydroxy Aldehydes". J. Am. Chem. Soc. 45 (10): 2373–77. doi:10.1021/ja01663a020.
  13. ↑ Adams, Roger (1957). Organic Reactions, Volume 9. New York: John Wiley & Sons, Inc. pp. 38 & 53–54. doi:10.1002/0471264180.or009.02. ISBN   9780471007265.
  14. ↑ Fuson, R. C.; Horning, E. C.; Rowland, S. P.; Ward, M. L. (1955). "Mesitaldehyde". Organic Syntheses . doi:10.15227/orgsyn.023.0057 ; Collected Volumes, vol. 3, p. 549.
  15. ↑ Robert Kane (1839) "On a series of combinations derived from pyroacetic spirit [acetone]" Transactions of the Royal Irish Academy, vol. 18, pages 99–125.
  16. ↑ Reichenbach's research is excerpted in: C. Reichenbach (1834) "Ueber Mesit (Essiggeist) und Holzgeist" (On mesit (spirit of vinegar) and wood spirits), Annalen der Pharmacie, vol. 10, no. 3, pages 298–314.
  17. ↑ For an explanation of the original of the name "mesitylene", see also: Henry E. Roscoe, A Treatise on Chemistry (New York, New York: D. Appleton and Co., 1889), vol. III, page 102, footnote 2.
  18. ↑ A.W. Hofmann (1849) "On the composition of mesitilole [mesitylene], and some of its derivatives", The Quarterly Journal of the Chemical Society of London, vol. 2, pages 104–115. (Note: The empirical formula of mesitylene as stated in Hofmann's paper (C18H12 ) is incorrect; however, this happened because Hofmann used 6 as the atomic weight of carbon, instead of the correct atomic weight of 12. Once the correct atomic weight is used in Hofmann's calculations, his results give the correct empirical formula of C9H12.)
  19. ↑ Adolf von Baeyer (1866) "Ueber die Condensationsproducte des Acetons" (On condensation products of acetone), Annalen der Chemie und Pharmacie, vol. 140, pages 297–306.
  20. ↑ Albert Ladenburg (1874) "Ueber das Mesitylen" (On mesitylene), Berichte der deutschen chemischen Gesellschaft, vol. 7, pages 1133–1137. doi : 10.1002/cber.18740070261
  21. ↑ Lee Irvin Smith (1931). "Isoodurene". Org. Synth. 11: 66. doi:10.15227/orgsyn.011.0066.
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