Why isn THF used as a solvent in the reduction reaction of nitrobenzaldehyde to nitrobenzyl alcohol?
I have done this reaction (and similar reductions of other aldehydes, such as Vanillin) using solvents such as acetonitrile, or biphasic systems such as methanol/water. I expect that THF wouldn’t be used on it’s own, due to poor solubility of the NaBH4. In theory it could be used to replace Methanol in the biphasic system, but it is more expensive, and more difficult to remove all traces in the final work-up procedure; Additionally there is the slight danger of peroxides present in THF: Nitro substituents may present a hazard, as they may cause their formation also, and peroxides may accumulate during the latter stage. Peroxide formation in Ethers is an under-rated and little encountered problem, but I have heard of one case where a lady dropped a bottle containging 2 litres of old Ether: it detonated on impact, killing her instantly.
