The unsaturated cyclic ether furan can readily be made from substances isolated from oat hulls and corncobs; important uses of furan involve its conversion into (a) tetrahydro- furan and (b) 1,4 -dichlorobutane. Show how these conversions can be carried out.

First, let's focus on the conversion of furan to tetrahydrofuran. Furan is an aromatic compound with an oxygen atom in the ring system and needs to undergo hydrogenation to become tetrahydrofuran, which is a saturated compound. A suitable reaction for this purpose is catalytic hydrogenation, where hydrogen gas (H2) reacts with the furan in the presence of a catalyst, such as palladium on carbon (Pd/C), to yield tetrahydrofuran. Furan + H2 → Tetrahydrofuran (in presence of Pd/C catalyst)

Next, let's consider the conversion of furan to 1,4-dichlorobutane. In this case, we need a two-step process: 1. Ring opening of furan 2. Halogenation of the open-chain diene The first step can be achieved by hydrolysis of the furan ring using an aqueous acid like H3O+. The hydrolysis opens the furan ring and forms a diol intermediate. Furan + H3O+ → 2,5-Dihydroxybutene The second step is halogenation, where we need to add two chlorine atoms to positions 1 and 4 of the open-chain diene. This can be achieved using a dihalogen compound such as Cl2, in the presence of a catalyst like aqueous HCl. This leads to the formation of the 1,4-dichlorobutane. 2,5-Dihydroxybutene + Cl2 → 1,4-Dichlorobutane (in presence of HCl) By following the steps outlined above, we have shown how furan can be converted into (a) tetrahydrofuran through catalytic hydrogenation and (b) 1,4-dichlorobutane through a combination of acid-catalyzed ring opening and halogenation.