2-Aryl-ethanol cpds. from aryl-acetaldehyde acetal cpds. - by acid-catalysed hydrolysis and hydrogenation at high pressure and temp. over ruthenium catalyst, useful as aroma or fragrance

摘要

Prodn. of 2-aryl-ethanols of the formula (R1)n-Ar-(CH2CH2-OH)m (I), where Ar = a benzene or naphthalene ring; R1 = H, R2, halogen, 1-6C alkoxy, perhaloalkyl, carboxy(m)ethoxy or OH; R2 - 1-6C alkyl; n = 1=5; and m = 1-3); comprises acid-catalysed hydrolysis and hydrogenation of the corresp. arylactaldehyde acetal of the formula (R1)n-(CH2-CH(OR2)2)m (II) in the presnce of water, H2 and a Ru catalyst (III) at elevated pressure and temp.. Reaction is carried out at 40-150 deg. C and a H2 pressure of 0.1-10 MPa, pref. using a strong inorganic or organic acid, esp. H2SO4 or H3PO4, and in the presence of an inert organic solvent, pref. an alcohol. (III) is metallic Ru, pref. on a C powderr. SiO2 or Al2O3 support. USE/ADVANTAGE - Very pure (I) are obtd. by a simple and economical process. They are of interest as aromas or fragrances.