反应详情

ε-Caprolactone (3000.0 g, 26.3 moles) was charged to a flask equipped with a mechanical stirrer and thermometer and cooled in an ice bath to below 5° C. A pre-cooled 30% solution of ammonium hydroxide (3100.0 g, 54.8 moles) was added and the reaction temperature was maintained below 5° C. until all caprolactone was consumed as indicated by gas chromatography. The water and excess ammonia were vacuum stripped at 50° C., at the completion of which the acid value was measured to be 2300. The acid by-product was removed via flocculation by addition of a methanolic solution of lithium hydroxide hydrate (58 g in 750 g methanol), ethyl acetate (2750 g), followed by isopropanol (250 g) until clarified. A second portion of ethyl acetate (2750 g) was added and the flocculated acid was filtered. All solvents were vacuum stripped at 50° C. to yield the 6-hydroxycaproamide (2750 g) as a pale yellow oil which crystallized upon standing at room temperature. Gas chromatographic and NMR spectral data indicated greater than 95% purity.

1. customequipped with a mechanical stirrer
2. temperaturethermometer and cooled in an ice bath to below 5° C
3. customwas consumed
4. customstripped at 50° C., at the completion of which
5. customThe acid by-product was removed via flocculation by addition of a methanolic solution of lithium hydroxide hydrate (58 g in 750 g methanol), ethyl acetate (2750 g)
6. additionA second portion of ethyl acetate (2750 g) was added
7. filtrationthe flocculated acid was filtered
8. customstripped at 50° C.