2-Methyltetrahydrofuran

Last updated
2-Methyltetrahydrofuran
Methyltetrahydrofuran.svg
Names
Preferred IUPAC name
2-Methyloxolane
Other names
2-Methyltetrahydrofuran, 2-Methyl-THF
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.002.281 OOjs UI icon edit-ltr-progressive.svg
EC Number
PubChem CID
UNII
UN number 2536
  • InChI=1S/C5H10O/c1-5-3-2-4-6-5/h5H,2-4H2,1H3 Yes check.svgY
    Key: JWUJQDFVADABEY-UHFFFAOYSA-N Yes check.svgY
  • (Racemic):InChI=1/C5H10O/c1-5-3-2-4-6-5/h5H,2-4H2,1H3
    Key: JWUJQDFVADABEY-UHFFFAOYAM
Properties
C5H10O
Molar mass 86.134 g·mol−1
Density 0.854 g/mL
Melting point −136 °C (−213 °F; 137 K) [1]
Boiling point 80.2 °C (176.4 °F; 353.3 K) [1]
21.0 wt% (0.0 °C)
17.8 wt% (9.5 °C)
14.4 wt% (19.3 °C)
11.4 wt% (29.5 °C)
9.2 wt% (39.6 °C)
7.8 wt% (50.1 °C)
6.6 wt%(60.7 °C)
6.0 wt% (70.6 °C) [2]
Hazards
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-acid.svg GHS-pictogram-exclam.svg
Warning
H225, H302, H315, H318, H319, H335, H336
P210, P233, P240, P241, P242, P243, P261, P264, P270, P271, P280, P301+P312, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P330, P332+P313, P337+P313, P362, P370+P378, P403+P233, P403+P235, P405, P501
Safety data sheet (SDS) External MSDS
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 ?)

2-Methyltetrahydrofuran (2-MeTHF) is an organic compound with the molecular formula C5H10O. It is a highly flammable, mobile liquid. It is mainly used as a replacement for Tetrahydrofuran (THF) in specialized applications for its better performance, such as to obtain higher reaction temperatures, or easier separations (as, unlike THF, it is not miscible with water). It is derived from sugars via furfural and is occasionally touted as a biofuel. [3]

Contents

Structures and properties

2-Methyltetrahydrofuran is "inversely soluble" in water. That is, its solubility decreases with increasing temperature, which is a rare property. [4] The solubility of water in 2-methyltetrahydrofuran is reported to be 4.4 g/ 100 g at 23 °C. [5] Much like tetrahydrofuran, 2-methyltetrahydrofuran can act as a Lewis base in organometallic reactions. [1] 2-Methyltetrahydrofuran is usually produced as a racemic mixture.

Preparation

2-Methyltetrahydrofuran is usually synthesized by catalytic hydrogenation of furfural. [6]

OC4H3CHO + 4 H2 → OC4H7CH3 + H2O

Furfural is produced by the acid-catalyzed digestion of pentosan sugars, C5 polysaccharides, in biomass. Thus, the raw materials of 2-methyltetrahydrofuran are renewable biomass rich with cellulose, hemicelluloses, and lignin, such as corncobs or bagasse and other plant and agricultural waste. [7]

2-Methyltetrahydrofuran can also be produced starting from levulinic acid. Cyclization and reduction gives γ-valerolactone:

Cyclization of levulinic acid.svg

γ-Valerolactone can be hydrogenated to 1,4-pentanediol, which can then be dehydrated to give 2-methyltetrahydrofuran:

Reaction of Valerolactone to 2Me-THF.svg

Applications

2-Methyltetrahydrofuran is mainly used as a higher boiling substitute for tetrahydrofuran as a specialty solvent. It also is used in the electrolyte formulation for secondary lithium electrodes and as a component in alternative fuels. It is a valued solvent for low-temperature reactions. 2-Methyltetrahydrofuran forms a glass, which does not crystallize, and is frequently used as a solvent for spectroscopic studies at −196 °C. [1]

Other common uses of 2-methyltetrahydrofuran is as a solvent for Grignard reagents used in organometallic and biphasic chemical processes, because of the oxygen atom's ability to coordinate to the magnesium ion component of the Grignard reagent, or to azeotropically dry products. The use of 2-methyltetrahydrofuran provides very clean organic water phase separations. It is a popular, but costlier substitute for tetrahydrofuran.

2-Methyltetrahydrofuran is approved by the United States Department of Energy as an additive to gasoline. Furfural and other furyl compounds (furfuryl alcohol, methylfuran, tetrahydrofufuryl alcohol) have a tendency to polymerize and are quite volatile. 2-Methyltetrahydrofuran itself, however, is more stable and less volatile, and thus is suitable for use as a motor fuel.

2-Methyltetrahydrofuran has been promoted as an ecologically-friendly alternative to THF. [8] Whereas 2-MeTHF is more expensive, it may provide for greater overall process economy. 2-MeTHF has solvating properties that are intermediate between diethyl ether and THF, has limited water miscibility, and forms an azeotrope with water on distillation. Its lower melting point makes it useful for lower temperature reactions, and its higher boiling point allows procedures under reflux at higher temperatures (relative to THF).

Related Research Articles

<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.

Furfural is an organic compound with the formula C4H3OCHO. It is a colorless liquid, although commercial samples are often brown. It has an aldehyde group attached to the 2-position of furan. It is a product of the dehydration of sugars, as occurs in a variety of agricultural byproducts, including corncobs, oat, wheat bran, and sawdust. The name furfural comes from the Latin word furfur, meaning bran, referring to its usual source. Furfural is only derived from dried biomass. In addition to ethanol, acetic acid, and sugar, furfural is one of the oldest organic chemicals available readily purified from natural precursors.

<span class="mw-page-title-main">Xylose</span> Sugar

Xylose is a sugar first isolated from wood, and named for it. Xylose is classified as a monosaccharide of the aldopentose type, which means that it contains five carbon atoms and includes an aldehyde functional group. It is derived from hemicellulose, one of the main constituents of biomass. Like most sugars, it can adopt several structures depending on conditions. With its free aldehyde group, it is a reducing sugar.

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

Lithium diisopropylamide is a chemical compound with the molecular formula LiN(CH 2)2. It is used as a strong base and has been widely utilized due to its good solubility in non-polar organic solvents and non-nucleophilic nature. It is a colorless solid, but is usually generated and observed only in solution. It was first prepared by Hamell and Levine in 1950 along with several other hindered lithium diorganylamides to effect the deprotonation of esters at the α position without attack of the carbonyl group.

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

Trimethylaluminium is one of the simplest examples of an organoaluminium compound. Despite its name it has the formula Al2(CH3)6 (abbreviated as Al2Me6 or TMA), as it exists as a dimer. This colorless liquid is pyrophoric. It is an industrially important compound, closely related to triethylaluminium.

<i>n</i>-Butyllithium Chemical compound

n-Butyllithium C4H9Li (abbreviated n-BuLi) is an organolithium reagent. It is widely used as a polymerization initiator in the production of elastomers such as polybutadiene or styrene-butadiene-styrene (SBS). Also, it is broadly employed as a strong base (superbase) in the synthesis of organic compounds as in the pharmaceutical industry.

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

Hydroxymethylfurfural (HMF), also known as 5-(hydroxymethyl)furfural, is an organic compound formed by the dehydration of reducing sugars. It is a white low-melting solid which is highly soluble in both water and organic solvents. The molecule consists of a furan ring, containing both aldehyde and alcohol functional groups.

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

tert-Butyllithium is a chemical compound with the formula (CH3)3CLi. As an organolithium compound, it has applications in organic synthesis since it is a strong base, capable of deprotonating many carbon molecules, including benzene. tert-Butyllithium is available commercially as solutions in hydrocarbons (such as pentane); it is not usually prepared in the laboratory.

<span class="mw-page-title-main">Zirconium(IV) chloride</span> Chemical compound

Zirconium(IV) chloride, also known as zirconium tetrachloride, is an inorganic compound frequently used as a precursor to other compounds of zirconium. This white high-melting solid hydrolyzes rapidly in humid air.

The Schlenk equilibrium, named after its discoverer Wilhelm Schlenk, is a chemical equilibrium taking place in solutions of Grignard reagents and Hauser bases

<span class="mw-page-title-main">Grignard reagent</span> Organometallic compounds used in organic synthesis

Grignard reagents or Grignard compounds are chemical compounds with the general formula R−Mg−X, where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride Cl−Mg−CH3 and phenylmagnesium bromide (C6H5)−Mg−Br. They are a subclass of the organomagnesium compounds.

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

Methyllithium is the simplest organolithium reagent, with the empirical formula CH3Li. This s-block organometallic compound adopts an oligomeric structure both in solution and in the solid state. This highly reactive compound, invariably used in solution with an ether as the solvent, is a reagent in organic synthesis as well as organometallic chemistry. Operations involving methyllithium require anhydrous conditions, because the compound is highly reactive towards water. Oxygen and carbon dioxide are also incompatible with MeLi. Methyllithium is usually not prepared, but purchased as a solution in various ethers.

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

Phenylmagnesium bromide, with the simplified formula C
6
H
5
MgBr
, is a magnesium-containing organometallic compound. It is commercially available as a solution in diethyl ether or tetrahydrofuran (THF). Phenylmagnesium bromide is a Grignard reagent. It is often used as a synthetic equivalent for the phenyl "Ph" synthon.

γ-Valerolactone Chemical compound

γ-Valerolactone (GVL) or gamma-valerolactone is an organic compound with the formula C5H8O2. This colourless liquid is one of the more common lactones. GVL is chiral but is usually used as the racemate. It is readily obtained from cellulosic biomass and is a potential fuel and green solvent.

<span class="mw-page-title-main">Superheated water</span> Pressurized liquid water at temperatures between the boiling and critical points

Superheated water is liquid water under pressure at temperatures between the usual boiling point, 100 °C (212 °F) and the critical temperature, 374 °C (705 °F). It is also known as "subcritical water" or "pressurized hot water". Superheated water is stable because of overpressure that raises the boiling point, or by heating it in a sealed vessel with a headspace, where the liquid water is in equilibrium with vapour at the saturated vapor pressure. This is distinct from the use of the term superheating to refer to water at atmospheric pressure above its normal boiling point, which has not boiled due to a lack of nucleation sites.

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

Borane dimethylsulfide (BMS) is a chemical compound with the chemical formula BH3·S(CH3)2. It is an adduct between borane molecule and dimethyl sulfide molecule. It is a complexed borane reagent that is used for hydroborations and reductions. The advantages of BMS over other borane reagents, such as borane-tetrahydrofuran, are its increased stability and higher solubility. BMS is commercially available at much higher concentrations than its tetrahydrofuran counterpart and does not require sodium borohydride as a stabilizer, which could result in undesired side reactions. In contrast, BH3·THF requires sodium borohydride to inhibit reduction of THF to tributyl borate. BMS is soluble in most aprotic solvents.

<span class="mw-page-title-main">Cyclopentyl methyl ether</span> Chemical compound

Cyclopentyl methyl ether (CPME), also known as methoxycyclopentane, is hydrophobic ether solvent. A high boiling point of 106 °C (223 °F) and preferable characteristics such as low formation of peroxides, relative stability under acidic and basic conditions, formation of azeotropes with water coupled with a narrow explosion range render CPME an attractive alternative to other ethereal solvents such as tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), dioxane, and 1,2-dimethoxyethane (DME).

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

Tetrahydrofurfuryl alcohol (THFA) is an organic compound with the formula HOCH2C4H7O. In terms of its structure, it consists of a tetrahydrofuran ring substituted in the 2-position with a hydroxymethyl group. It is a colorless liquid that is used as a specialty solvent and synthetic intermediate, e.g. to 3,4-dihydropyran. It is prepared by hydrogenation of furfural. It is a precursor to 1,5-pentanediol.

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References

  1. 1 2 3 4 Aycock, David F. (2007). "Solvent Applications of 2-Methyltetrahydrofuran in Organometallic and Biphasic Reactions". Org. Process Res. Dev. 11: 156–159. doi:10.1021/op060155c.
  2. Sicaire, Anne-Gaëlle; Vian, Maryline Abert; Filly, Aurore; Li, Ying; Bily, Antoine; Chemat, Farid (2014), Chemat, Farid; Vian, Maryline Abert (eds.), "2-Methyltetrahydrofuran: Main Properties, Production Processes, and Application in Extraction of Natural Products", Alternative Solvents for Natural Products Extraction, Berlin, Heidelberg: Springer Berlin Heidelberg, pp. 253–268, doi:10.1007/978-3-662-43628-8_12, ISBN 978-3-662-43627-1
  3. Leal Silva, Jean Felipe; Mariano, Adriano Pinto; Maciel Filho, Rubens (2018). "Economic potential of 2-methyltetrahydrofuran (MTHF) and ethyl levulinate (EL) produced from hemicelluloses-derived furfural". Biomass and Bioenergy. 119 (December 2018): 492–502. Bibcode:2018BmBe..119..492L. doi:10.1016/j.biombioe.2018.10.008. S2CID   104836889.
  4. Sicaire, Anne-Gaëlle; Vian, Maryline Abert; Filly, Aurore; Li, Ying; Bily, Antoine; Chemat, Farid (2014), Chemat, Farid; Vian, Maryline Abert (eds.), "2-Methyltetrahydrofuran: Main Properties, Production Processes, and Application in Extraction of Natural Products", Alternative Solvents for Natural Products Extraction, Berlin, Heidelberg: Springer Berlin Heidelberg, pp. 253–268, doi:10.1007/978-3-662-43628-8_12, ISBN   978-3-662-43627-1
  5. "Zeon Corporation" (PDF). Archived from the original (PDF) on 2011-07-22. Retrieved 2024-08-05.
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  7. Hoydonckx, H. E.; Van Rhijn, W. M.; Van Rhijn, W.; De Vos, D. E.; Jacobs, P. A. "Furfural and Derivatives". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a12_119.pub2. ISBN   978-3527306732.
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Further reading