Abstract: There is disclosed a process for producing 3-methyl-tetrahydrofuran which comprises the step 1 of subjecting the compound represented by the general formula [I]ROOC--CH(CH.sub.3)--CH.sub.2 --CHO [I]wherein R is an alkyl group having 1 to 3 carbon atoms and the formyl group may be present as an acetal having an alkanol with 1 to 8 carbon atoms, to hydrogenation and alcohol-eliminating cyclization to synthesize 2-methyl-.gamma.-butyrolactone; the step 2 of separating the 2-methyl-.gamma.-butyrolactone formed in the step 1 from alcohols by means of distillation, etc.; and the step 3 of hydrogenating the 2-methyl-.gamma.-butyrolactone which is formed in the step 2. The above process enables the production of the objective highly-pure 3-methyltetrahydrofuran substantially free from an alcohol in high efficiency and high conversion through simplified production steps.

Abstract: There is disclosed a process for producing 3-methyltetrahydrofuran substantially free from any of an alcohol and water which comprises adding an organic solvent capable of forming an azeotropic mixture with an alcohol with an alkyl group having 1 to 3 carbon atoms to a mixed liquid containing 3-methyltetrahydrofuran, the alcohol and/or water as the principal components and, as the case may be, another substance, and distilling the resultant mixture of the mixed liquid and said organic solvent. According to the above process, it is made possible to efficiently separate a mixture of 3-methyltetrahydrofuran and an alcohol and/or water which mixture is difficult to separate with conventional distillation process alone, thereby efficiently producing the objective 3-methyltetrahydrofuran substantially free from any of an alcohol and water.

Abstract: A process for preparing 3-methyltetrahydrofuran is herein disclosed which comprises reacting a methacrylic acid ester with carbon monoxide and a lower aliphatic alcohol to obtain a methylsuccinic acid diester, and hydrogenating and dehydrating/cyclizing this methylsuccinic acid diester. According to this process, 3-methyltetrahydrofuran can efficiently be obtained from inexpensive starting materials.

Abstract: A process for producing 3-methyltetrahydrofuran, wherein in a first step, prussic acid is reacted with methyl methacrylate to produce methyl 3-cyanoisobutyrate. The methyl 3-cyanoisobutyrate is then reacted with water and sulfuric acid to produce a resultant product which is reacted with a C.sub.1 -C.sub.8 aliphatic alcohol to produce a methylsuccinic acid ester. The methylsuccinic acid ester is catalytically hydrogenated to prepare the 3-methyltetrahydrofuran. Alternatively, the methyl 3-cyanoisobutyrate is hydrated to produce methyl 3-carbamoylisobutyrate, which is then reacted with a formic acid ester to form a methylsuccinic acid ester and formamide and the resultant methylsuccinic acid ester is catalytically hydrogenated. The 3-methyltetrahydrofuran is produced in high selectivity and in a commercially advantageous manner from inexpensive reactants. The 3-methyltetrahydrofuran is useful as a commoner for producing polyether glycol, which is utilized as starting raw material for preparing spandex fiber.