Methylfuran

2-Methylfuran is a cyclic diene passessing ether-like properties. It is highly reactive with many inorganic and organic compaunds yielding a variety of new derivatives which await exploration for the development af commercial applications. 

Freexing point Specific gravity. aO C./4 C. Index of refraction, N20/O Flash point 

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Uses. Furfural is primarily a chemical feedstock for a number of monomeric compounds and resins. One route produces furan by decarbonylation. Tetrahydrofuran is derived from furan by hydrogenation. Polytetramethylene ether glycol [25190-06-1] is manufactured from tetrahydrofuran by a ring opening polymeri2ation reaction. Another route (hydrogenation) produces furfuryl alcohol, tetrahydrofurfuryl alcohol, 2-methylfuran, and 2-methyltetrahydrofuran. A variety of proprietary synthetic resins are manufactured from furfural and/or furfuryl alcohol. Other... 

Hydrogenation of furfuryl alcohol can yield 2-tetrahydrofurfuryl alcohol, 2-methylfuran, 2-methyltetrahydrofuran, or straight-chain compounds by hydrogenolysis of the ring. Ethoxylation and propoxylation of furfuryl alcohol provide usefiil ether alcohols. 

Since double bonds are no longer present, these compounds are more stable than the corresponding furan derivatives. Tetrahydrofurfuryl alcohol—ethylene oxide adducts [31692-85-0] are also usehil solvents for paint stripping formulations (136,141,143). 2-Methylfuran is a good solvent, but... 

Intermediates. 3,4-Dihydro-2H-pyran [110-87-2] is prepared by a ring-expanding dehydration of tetrahydrofurfuryl alcohol. It is used as a protecting agent for hydroxyl compounds and as an intermediate. 2-Methylfuran is a chemical intermediate for 5-methylfurfural [620-02-0] (151) and... 

Aminofurans substituted with electron-withdrawing groups e.g. NO2) are known and 3-amino-2-methylfuran is a relatively stable amine which can be acylated and diazotized. 2-Amino-3-acetylfurans are converted into 3-cyano-2-methylpyrroles on treatment with aqueous ammonia. This transformation is a further illustration of the relative instability of the amino derivatives of five-membered ring heterocycles compared with anilines (Scheme 67) (781003821). 

Methylfuran [534-22-5] M 82.1, b 62.7-62.8 /731mm, d 0.917, n 1.436. Washed with acidified satd ferrous sulfate soln (to remove peroxides), separated, dried with CaS04 or CaCl2, and fractionally distd from KOH immediately before use. To reduce the possibility of spontaneous polymeri.sation, addition of about one-third of its volume of heavy mineral oil to 2-methylfuran prior to distn has been recommended. 

Furoic acid has been made by oxidation of lactose followed by pyrolysis, by the oxidation of 2-acetylfuran, 2-methylfuran, or furfuryl alcohol using potassium ferricyanide in alkaline medium, and by other methods already listed. ... 

Patemo-Biichi reaction between 2-methylfuran 31 and an a-hydroxyaldehyde 30 to form the core oxetane. Two of the three stereocenters set in the electrocyclization appear in the final product while the third is selectively reversed with anomeric assistance. 

Methylfuran, irradiated in the presence of mercury vapor, gave carbon monoxide and a fraction containing 1,3-butadiene and 3-methylcyclopropene (45 55) (67JA1758). Subsequently, it was found that in both sensitized and direct photolysis of 2-methylfuran a more complex mixture of products was obtained, where 3-methylfuran was present (Scheme 5) (68JA2720 70JPC574). 3-Methylfuran was the only product when 2-methylfuran was irradiated in diethyl ether (68JA2720). 

Mercury-sensitized irradiation of 3-methylfuran gave 2-butyne, 1,2-pentadiene, 1-methylcyclopropene, 1-butyne, and 1,3-butadiene (Scheme 6) (68JA2720 70JPC574). In the direct irradiation, 1-methylcyclopropene was obtained in lower yields while both 3-methylcyclopropene and 2-methylfuran appeared (Scheme 6) (70JPC574). 

The calculated relative energies of all the possible intermediates involved in the photochemical isomerization are collected in Fig. 4 (OOOJOC2494). In this case the irradiation can involve the excited singlet state, and then the formation of Dewar isomer is possible. As in 2-methylfuran, the fission of a O—Cq, bond in the triplet state of the molecule is not so favored as in furan. The corresponding biradicals... 

Methylenc-2,5-dihydrofuran (111), which has been isolated by Rice, < is converted by acid into 2-methylfuran. 

The synthesis of phosphonium iodide 24, the precursor of phos-Br phorus ylide 12, begins with the alkylation of 5-lithio-2-methyl- furan,10 derived from the action of n-butyllithium on 2-methylfuran 17 (16), with 1,4-dibromobutane (17) to give 15 in 75% yield (see... 

High-valency metal fluoride fluorination of pyridine [82JFC(21)171], quinoline [82JFC(21)413], and 2-methylfurans [91 JFC(51)179] has been reported. With 2-methylfuran a complex mixture of stereoisomers of partially fluorinated oxolans was obtained. These can be dehydrofluorinated to fluorooxolens and no furans have been observed. Conformation and structural group were found to influence the direction and readiness toward dehydrofluorination [91 JFC(52) 165]. 

The addition of 2-me-thylfuran, thiophene, 2-methylthiophene, pyrrole, and 4—methylthiazole to propylene carbonate-LiPF6 or propylene carbonate-THF-LiPF, improved the cycling efficiency [109]. THF-2MeTHF- Li AsF6 with an additional of 2-methylfuran showed the longest cycle life [110, 111]. 

The addition of some metal ions, such as Mg2+,Zn2+, In3+,orGa3+, and some organic additives, such as 2-thiophene, 2-methylfuran, or benzene, to propylene carbonate-LiC104 improved the coulombic efficiency for lithium cycling [112]. Lithium deposition on a lithium surface covered with a chemically stable, thin and tight layer which was formed by the addition of HF to electrolyte can suppress the lithium dendrite formation in secondary lithium batteries [113]. 

Matsuda and co-workers [75, 76] examined Lil, Snl2, A1I3 and 2MeF (2-methylfuran) as additives in LiC104-PC or LiC104-PC/DMC electrolyte. They measured the cycling efficiency of lithium on an Ni electrode. All the additives increased the efficiency the best additive... 

Lithium hexafluoroarsenate is thermally stable [54, 55] but shows environmental risks due to possible degradation products [56-58], even though it is itself not very toxic. Its LD 50 value is similar to that of lithium perchlorate [55]. Just like lithium hexafluorophosphate, it can initiate the polymerization of cyclic ethers. Polymerization may be inhibited by tertiary amines [59], or 2-methylfuran [60], yielding highly stable electrolytes. 

The first reports on enantioselective addition reactions of achiral organometallic reagents, modified by aprotic chiral additives, described the addition of Grignard reagents to prostereogenic carbonyl compounds in the presence of ( + )-(/ ,/J)-2,3-dimethoxybutane (l)4 5, (-)-tetrahydro-2-methylfuran (2)6, (-)-l-[(tetrahydro-2-furanyl)methyl]pyrrolidine (3)7 or (-)-sparteine (4)8. The enantioselectivity, however, was poor (0-22% ee). 

A mechanism for its formation was also proposed. Essentially, this involved protonation of 2-methylfuran followed by dimerization and trimerization to a 2,4-difuryl tetrahydrofuran derivative which suffered an acid catalysed cleavage of the saturated ring to produce a carbenium ion possessing an alcoholic function at the other end of... 

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