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 a functional group 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 in industry. Examples include many sugars (ketoses), many steroids, and the solvent acetone.

Pyrimidine is an aromatic, heterocyclic, organic compound similar to pyridine. One of the three diazines, it has nitrogen atoms at positions 1 and 3 in the ring. The other diazines are pyrazine and pyridazine.

The Friedel–Crafts reactions are a set of reactions developed by Charles Friedel and James Crafts in 1877 to attach substituents to an aromatic ring. Friedel–Crafts reactions are of two main types: alkylation reactions and acylation reactions. Both proceed by electrophilic aromatic substitution.

<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">Acyl halide</span> Oxoacid compound with an –OH group replaced by a halogen

In organic chemistry, an acyl halide is a chemical compound derived from an oxoacid by replacing a hydroxyl group with a halide group.

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

Anthraquinone, also called anthracenedione or dioxoanthracene, is an aromatic organic compound with formula C
14H
8O
2. Isomers include various quinone derivatives. The term anthraquinone however refers to the isomer, 9,10-anthraquinone wherein the keto groups are located on the central ring. It is a building block of many dyes and is used in bleaching pulp for papermaking. It is a yellow, highly crystalline solid, poorly soluble in water but soluble in hot organic solvents. It is almost completely insoluble in ethanol near room temperature but 2.25 g will dissolve in 100 g of boiling ethanol. It is found in nature as the rare mineral hoelite.

<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 odor.

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

Dibenzylideneacetone or dibenzalacetone, often abbreviated dba, is an organic compound with the formula C17H14O. It is a pale-yellow solid insoluble in water, but soluble in ethanol.

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

Nitrosobenzene is the organic compound with the formula C6H5NO. It is one of the prototypical organic nitroso compounds. Characteristic of its functional group, it is a dark green species that exists in equilibrium with its pale yellow dimer. Both monomer and dimer are diamagnetic.

The Gattermann reaction, (also known as the Gattermann formylation and the Gattermann salicylaldehyde synthesis) is a chemical reaction in which aromatic compounds are formylated by a mixture of hydrogen cyanide (HCN) and hydrogen chloride (HCl) in the presence of a Lewis acid catalyst such as AlCl3. It is named for the German chemist Ludwig Gattermann and is similar to the Friedel–Crafts reaction.

The Blanc chloromethylation is the chemical reaction of aromatic rings with formaldehyde and hydrogen chloride to form chloromethyl arenes. The reaction is catalyzed by Lewis acids such as zinc chloride. The reaction was discovered by Gustave Louis Blanc (1872-1927) in 1923

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">Trimethyl phosphite</span> Chemical compound

Trimethyl phosphite is an organophosphorus compound with the formula P(OCH3)3, often abbreviated P(OMe)3. It is a colorless liquid with a highly pungent odor. It is the simplest phosphite ester and finds used as a ligand in organometallic chemistry and as a reagent in organic synthesis. The molecule features a pyramidal phosphorus(III) center bound to three methoxy groups.

<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.

4-Nitrotoluene or para-nitrotoluene is an organic compound with the formula CH3C6H4NO2. It is a pale yellow solid. It is one of three isomers of nitrotoluene.

<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">Benzylidene acetal</span> Functional group

In organic chemistry, a benzylidene acetal is the functional group with the structural formula C6H5CH(OR)2 (R = alkyl, aryl). Benzylidene acetals are used as protecting groups in glycochemistry. These compounds can also be oxidized to carboxylic acids in order to open important biological molecules, such as glycosaminoglycans, to other routes of synthesis. They arise from the reaction of a 1,2- or 1,3-diols with benzaldehyde. Other aromatic aldehydes are also used.

<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., 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.; Collective Volume, 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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