One‐Pot Catalytic Conversion of Lignin‐Derivable Guaiacols and Syringols to Cyclohexylamines. Issue 18 (1st August 2022)

• Record Type: Journal Article
• Authors: Wu, Xianyuan; De bruyn, Mario; Barta, Katalin
• Is Part Of: ChemSusChem. Volume 15:Issue 18(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-01
• Subjects: amines -- catalytic amination -- cyclohexylamines -- reductive catalytic fractionation -- sustainable chemistry; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.202200914
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: Cyclic primary amines are elementary building blocks to many fine chemicals, pharmaceuticals, and polymers. Here, a powerful one‐pot Raney Ni‐based catalytic strategy was developed to transform guaiacol into cyclohexylamine using NH3 (7 bar) and H2 (10 bar) in up to 94 % yield. The methodology was extendable to the conversion of a wider range of guaiacols and syringols into their corresponding cyclohexylamines. Notably, a crude bio‐oil originating from the reductive catalytic fractionation of birch lignocellulose was transformed into a product mixture rich in 4‐propylcyclohexylamine, constituting an interesting case of catalytic funneling. The isolated yield of the desired 4‐propylcyclohexylamine reached as high as 7 wt % (on lignin basis). Preliminary mechanistic studies pointed at the consecutive occurrence of three key catalytic transformations, namely, demethoxylation, hydrogenation, and amination. Abstract : All in one : A one‐pot catalytic methodology enables the production of industrially relevant cyclohexylamines in good to excellent yields over Raney Ni catalyst/ t‐ amyl alcohol, using NH3 and H2 at 180 °C, and generating water and methanol as the only side products.