3-Methylfuran, atmosphere

TABLE 5. External pressure dependence on the reaction of 2-methylfuran with several dienophiles82 (these reactions do not proceed at atmospheric pressure)... 

Other toxic lung furans, such as the atmospheric contaminants 2-methylfuran and 3-methylfuran, may exert their toxicity through the formation of reactive metabolites, probably reactive aldehydes. 

On the other hand, Gavrilova and Gonikberg opened the furan ring with hydrogen, without the use of catalysts.213 The reaction is carried out at high temperature (350-375°) and at a pressure between 240 and 750 atmospheres, in the absence of a solvent. The following products are obtained from 2-methylfuran acetone, methyl ethyl ketone, methyl butyl ketone, methyl amyl ketone, acetophenone, methylpropylcarbinol, w-pentane, and water. The authors suggest that these products are formed by a free radical mechanism. 

Methylfuran, more precisely 2-methylfiiran, also known as sylvan, a colorless liquid having an atmospheric boiling point of 63 °C, can be produced from furfural in very much the same fashion as fiirfiiryl alcohol, but at a higher temperature. 

Although the reaction given above calls for a molar hydrogen to furfural ratio of only 2 1, it is recommended to run the process at a ratio between 6 1 and 7 1. This means that in an atmospheric process the furfural in the vaporizer should have a temperature of 104 °C as at this temperature the furfural has a vapor pressure of 100 torr, so that the molar hydrogen to furfural ratio is (760 - 100)/100 = 6.6. Under these conditions, the yield of 2-methylfuran is 92.5 percent. Apart from the inevitable reaction water, the principal by-product is furfuryl alcohol. 

Methylfuran is obtained at atmospheric pressure when furfuraldehyde is led in a stream of hydrogen over a copper chromite catalyst finely spread over charcoal at 200-230°.503... 

Davis AC, Sarathy SM. Computational study of the combustion and atmospheric decomposition of 2-methylfuran. J Phys Chem A. 2013 117 7670-7685. 

Somers KP, Sirmrde JM, Gillespie F, et al. A high temperature and atmospheric pressure experimental and detailed chemical kinetic modelling study of 2-methylfuran oxidation. Proc Combust Inst. 2013 34 225-232. 

The 2,3-dihydro-5-methylfuran species is formed in the atmosphere at low humidity via the cyclization and subsequent dehydration of 5-hydroxy-2-pentanone, itself an important product in the oxidation of pentane (Martin et al., 2002). Similar species are expected to be formed in the oxidation of other alkanes (C4 and larger), when isomerization of the initially formed alkoxy radical is of importance. Similarly, the species 5-methyl-5-vinyl-tetrahydrofuran-2-ol is a by-product of linalool oxidation, formed via the cyclization of an initially formed unsaturated hydroxycarbonyl species (Calogirou et al., 1999). The available data are summarized in table III-E-30. 

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