Base-free conversion of glycerol to methyl lactate using a multifunctional catalytic system consisting of Au–Pd nanoparticles on carbon nanotubes and Sn-MCM-41-XS. Issue 15 (10th July 2019)

• Record Type: Journal Article
• Authors: Tang, Zhenchen; Boer, Dina G.; Syariati, Ali; Enache, Mihaela; Rudolf, Petra; Heeres, Hero J.; Pescarmona, Paolo P.
• Is Part Of: Green chemistry. Volume 21:Issue 15(2019)
• Page Start: 4115
• Page End: 4126
• Publication Date: 2019-07-10
• Subjects: Environmental chemistry -- Industrial applications -- Periodicals; Environmental management -- Periodicals; 660
• DOI: 10.1039/c9gc01521c
• Languages: English
• ISSNs: 1463-9262

Abstract

Abstract : Base-free, multifunctional heterogenous catalytic systems for the highly efficient conversion of glycerol into methyl lactate. Abstract : Multifunctional catalytic systems consisting of physical mixtures of (i) bimetallic Au–Pd nanoparticles (average size of 3–5 nm) supported on functionalised carbon nanotubes (CNTs) and (ii) Sn-MCM-41 nanoparticles (50–120 nm), were synthesised and investigated for the base-free, selective conversion of glycerol to methyl lactate in a batch reactor. The catalysts were characterised by means of transmission electron microscopy, N2 -physisorption, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and by Boehm titration. The catalyst based on bimetallic AuPd/CNTs showed much higher activity than the monometallic Au or Pd counterparts, thus indicating synergetic effects. Functionalisation of the CNTs by oxidative treatments had a positive effect on catalyst performance, which was correlated to the observed increase in surface acidity and hydrophilicity. The highest yield of methyl lactate achieved in this work was 85% at 96% glycerol conversion (140 °C, 10 h at 30 bar air), which is the highest yield ever reported in the literature so far. Insights in the reaction pathway were obtained by monitoring the conversion-time profiles for intermediates and their possible role as inhibitors. Batch recycling experiments demonstrated the excellent reusability of the catalyst.