Synthesis of Helional by Hydrodechlorination Reaction in the Presence of Mono- and Bimetallic Catalysts Supported on Alumina

• Published in: Catalysts Vol. 14; no. 4; p. 255
• Main Authors: Piccolo, Oreste, Arčon, Iztok, Das, Gangadhar, Aquilanti, Giuliana, Prai, Andrea, Paganelli, Stefano, Facchin, Manuela, Beghetto, Valentina
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.04.2024
• Subjects: Aldehydes; Aluminum oxide; Analysis; Atomic structure; Bimetals; Catalysts; Catalytic activity; Chemical synthesis; Copper base alloys; Efficiency; EXAFS analysis; Experiments; Helional; heterogeneous catalysis; Hydrodechlorination; Hydrogenation; Methods; Methyl groups; Nanoparticles; Palladium; Properties; Rhodium; selective hydrodechlorination; Structure; Substrates; XANES analysis; Italy
• ISSN: 2073-4344; 2073-4344
• DOI: 10.3390/catal14040255

Hydrodechlorination reaction of 3-(benzo-1,3-dioxol-5-yl)-3-chloro-2-methylacrylaldehyde in the presence of different low metal content heterogeneous mono- or bimetallic catalysts was tested for the synthesis of the fragrance Helional® (3-[3,4-methylendioxyphenyl]-2-methyl-propionaldehyde). In particular, mono Pd/Al2O3, Rh/Al2O3 or bimetallic Pd-Cu/Al2O3, Rh-Cu/Al2O3 catalysts were tested in different reaction conditions from which it emerged that mono-Rh/Al2O3 was the best performing catalyst, allowing achievement of 100% substrate conversion and 99% selectivity towards Helional® in 24 h at 80 °C, p(H2) 1.0 MPa in the presence of a base. To establish correlations between atomic structure and catalytic activity, catalysts were characterized by Cu, Rh and Pd K-edge XANES, EXAFS analysis. These characterizations allowed verification that the formation of Pd-Cu alloys and the presence of Cu oxide/hydroxide species on the surface of the Al2O3 support are responsible for the very low catalytic efficiency of bimetallic species tested.