ABSTRACT
Catalytic aromatic hydrogenation of 2-methoxy-4-propylphenol (1) and a milled wood lignin (MWL) was achieved using various Ru sysMns (e.g. RuCh·JH20, RuCl2(arene)(sulfonated phosphine), Ru2Cl.(arene)2, and [Ru.Jit(arene)4]Ch) with or without basic co-reagents in H20, i>rOH, 'PrOH/H20 or ClCH2CH2Cl/H20 media at 80-100 oc under 50-60 atm H2• For 1, complete conversions with selectivities for 2-methoxy-4-propylcyclohexanol (1a) up to 91.3% are seen, while for MWL, conversions up to 64.9% hydrogenated MWL (HMWL) can be achieved. For catalyst systems utilizing water-soluble sulfonated phosphines, homogeneity was maintained, but the systems were generally less active than the non-phosphine systems, which involved active colloidal species that eventually precipitated as inactive metal. Photo-accelerated yellowing studies revealed complete photostability for 1a and a yellowing inhibition of at least 50% for HMWL.
