The synthesis of a new tripodal phosphine ligand, N(CH(2)PEt(2))(3), N-TriPhos(Et) is reported, and the use of tripodal ligands of this type, N(CH(2)PR(2))(3) (R=Ph, Et), in conjunction with ruthenium for the catalysed hydrogenation of dimethyl oxalate (DMO) is reported and contrasted with catalysis using the MeC(CH(2)PPh(2))(3) (TriPhos(Ph)) ligand. A different order of reaction with respect to the DMO substrate is found, and the rate is slower. A study of the kinetics and mechanism of the hydrogenation of DMO with Ru(acac)(3)/TriPhos(Ph) is described, along with the effect of different additives to the system. The performance of Ru(acac)(3)/TriPhos(Ph)/Zn system with unactivated ester substrates is probed and found to proceed significantly slower. Finally, based upon experimental observations, a mechanism is proposed for ester hydrogenation using ruthenium catalysts with tripodal phosphine ligands. (C) 2011 Elsevier B.V. All rights reserved.