Pentamethyldiethylenetriamine is a permethylated polyamine that is widely used to prepare foam polyurethane. The current technology for its synthesis relies on diethylenetriamine methylation with formaldehyde under H2. This route is selective, but the use of formaldehyde raises safety and environmental concerns. Herein we present an alternative non-toxic route using methanol as greener and cheaper methylating reagent. The reaction proceeds fast and selectively over composite copper catalysts with a pentamethyldiethylenetriamine yield of 75% and resistance to sintering.
