2-Methyltetrahydrofuran
- Methyltetrahydrofuran
- Tetrahydro -2-methylfuran
- 96-47-9 (racemate )
- 63798-12-9 ((S ) - ( )- enantiomer)
- 63798-13-0 ((R) - (-) - enantiomer)
Liquid
0.854 g · cm -3 ( racemate)
-136 ° C ( racemate)
80.3 ° C ( racemate)
136 mbar (20 ° C) ( racemate)
14 g/100 g water (20 ° C) ( racemate)
1.4059 (21 ° C)
Risk
4500 mg · kg -3 ( LD50, Rabbit, transdermal)
Template: Infobox chemical / molecular formula search available
2-methyltetrahydrofuran is an organic solvent and is part of the class of cyclic ethers.
Production and representation
2-methyltetrahydrofuran as a by- product in the industrial production of furfural into furfuryl alcohol. It can also be prepared by a nickel -catalyzed hydrogenation of 2- methylfuran. This can be obtained from the accessible through reprocessing plant pentoses, furfural, so that the production of 2- methyltetrahydrofuran can be made entirely of renewable raw materials.
A newer method is about cyclization and hydrogenation of levulinic acid, which can also be derived from carbohydrates. All commercial manufacturing processes result in the racemate. A separation of enantiomers can be carried out by chromatography on chiral stationary phases with supercritical media. The synthesis of (S ) - ( )-2- Methyltetrahydrofurans achieved by the hydrogenation of 2 - methylfuran by chiral rhodium complex catalysts.
Properties
Stereochemistry
The compound contains a chiral center and thus can occur in the form of two enantiomers. However, has practical significance only the racemate.
Physical Properties
2-methyltetrahydrofuran is a colorless, low-viscosity liquid with a characteristic odor. The boiling point at normal pressure is 80.3 ° C. The vapor pressure function is given by Antoine corresponding log10 (P) = A- ( B / ( T C)) (P in kPa, T in ° C) with A = 5.95009, B = 1175.51 and C = 217.80. The critical point was determined with a critical temperature at 537 K, a critical pressure at 37.58 bar and a critical volume of 0.267 l · mol -1.
With a water content of 10.6 % by mass of the compound forms an azeotrope boiling at 71 ° C. Further azeotropically boiling mixtures are formed with methanol, ethanol, 1 -propanol and 2 -propanol.
At 20 ° C, dissolve in 100 g water 14 g methyltetrahydrofuran, conversely, 4 g of water dissolved in 100 g methyltetrahydrofuran. The solubility of water in 2- methyltetrahydrofuran changes only little with increasing temperature. In contrast, the solubility in water decreases from methyltetrahydrofuran with increasing temperature.
Safety characteristics
2-methyltetrahydrofuran forms flammable vapor - air mixtures. The compound has a flash point less than -12 ° C. The explosion range is between 1.5 vol % for the lower explosive limit ( LEL) and 8.9 vol% as the upper explosive limit ( UEL). A correlation of the explosion limits of the vapor pressure of function results in a lower explosion point of -15 ° C and an upper explosion point of 18 ° C. The ignition temperature is 270 ° C. The fabric falls within the temperature class T3.
Chemical Properties
2-methyltetrahydrofuran in the presence of air tends how many other ethers in the formation of peroxides. The rate of peroxide formation is similar to that of tetrahydrofuran. The commercial product contains butylated hydroxytoluene as a stabilizer. The unstabilized product tends in the presence of light or air to form peroxides. However, it is much more stable than tetrahydrofuran to acids.
Use
2-methyltetrahydrofuran is seen as solvent Altenative to tetrahydrofuran especially in organometallic reactions. For one, it has also at low temperatures such as -70 ° C with 1.85 cp a low viscosity, on the other hand, the temperature range can be used to the higher boiling point of 80 ° C. Since the connection glassy solidifies on cooling below the melting point, it can be used as a solvent at -196 ° C with spectroscopic studies. A use as a blending component in gasoline has been successfully tested in the USA. In organic chemistry it is used as a reactant for the production of N-substituted 2- Methylpyrrolidine.