Benzyl alcohol and cyclohexanol can be distinguished by examining their UV-Vis spectra due to differences in conjugation, by using IR spectroscopy to detect aromatic C-H stretching in benzyl alcohol, or by observing reactivity differences in chemical reactions such as bromination.
To distinguish between benzyl alcohol and cyclohexanol without using the Lucas test, one can use spectroscopic methods or chemical reactivity tests. Benzyl alcohol has a benzene ring attached to the hydroxyl group, which results in a distinct ultraviolet-visible (UV-Vis) spectrum due to the conjugated system of the benzene ring, whereas cyclohexanol, which lacks this conjugation, will have a different UV-Vis spectrum.
In addition, infrared (IR) spectroscopy can be used. Benzyl alcohol would show a characteristic peak for aromatic C-H stretching around 3000 cm-1, while cyclohexanol will not. The presence of an aromatic ring in benzyl alcohol can also be confirmed by reactions like bromination, where benzyl alcohol would react readily due to the ring's increased reactivity compared to the cyclohexanol.