tags
ammoniadiethylsodium thiosulfatealdehydesiodinevanillinbenzaldehydephosphorus pentoxidealdehydecitric acidnitrogen triiodideethersodium hydrogen sulfidecreosolethanolphenolic aldehydes
video tutorial Nitrogen triiodide - can it convert aldehyde to nitrile
- Topic: testing a claimed method to convert an aromatic aldehyde to a nitrile using iodine and aqueous ammonia; the catch is the in-situ formation of the explosive nitrogen triiodide–ammonia complex.
- Observations: reacting iodine with strong aqueous ammonia yields a black solid (nitrogen triiodide–ammonia adduct) rather than a simple dissolution; the reaction is extremely hazardous, especially in larger, confined setups.
- Experiment with vanillin (5 g) as the substrate: iodine (4.5 g, slight excess) and 50 mL of 20% ammonia in ethanol as co-solvent; vanillin dissolves to a pale yellow solution; iodine is added in portions with stirring; the mixture darkens and a white precipitate forms after about 40 minutes; the mixture is chilled to maximize precipitate.
- Isolation and notes: the precipitate is >4 g, dense and clumpy; drying is slow; suspicion that product has absorbed iodine, suggesting formation of 5-iodovanillin rather than a nitrile; qualitative tests imply aldehyde character remains, not a nitrile.
- Workup and analysis: extraction of filtrate with diethyl ether yields trace material with vanillin-like aroma; attempts to purify suggest the major product is likely an iodinated vanillin derivative; thiosulfate wash does not remove brown color; overall yield and identity are inconclusive.
- Conclusion: vanillin is too reactive toward electrophilic iodine in the basic, ammonia-rich medium; the intended nitrile formation is unlikely for this substrate under these conditions; future work would test less reactive aldehydes; safety concerns with nitrogen triiodide formation are emphasized.
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