Abstract
Succinic acid is a biomass-derived platform chemical that can be catalytically converted in the aqueous phase to 1,4-butanediol (BDO), a prevalent building block used in the polymer and chemical industries. Despite significant interest, limited work has been reported regarding sustained catalyst performance and stability under continuous aqueous-phase process conditions. As such, this work examines Ru-Sn on activated carbon (AC) for the aqueous-phase conversion of succinic acid to BDO under batch and flow reactor conditions. Initially, powder Ru-Sn catalysts were screened to determine the most effective bimetallic ratio and provide a comparison to other monometallic (Pd, Pt, Ru) and bimetallic (Pt-Sn, Pd-Re) catalysts. Batch reactor tests determined that a ∼1:1 metal weight ratio of Ru to Sn was effective for producing BDO in high yields, with complete conversion resulting in 82% molar yield. Characterization of the fresh Ru-Sn catalyst suggests that the sequential loading method results in Ru sites that are colocated and surface-enriched with Sn. Postbatch reaction characterization confirmed stable Ru-Sn material properties; however, upon a transition to continuous conditions, significant Ru-Sn/AC deactivation occurred due to stainless steel leaching of Ni that resulted in Ru-Sn metal crystallite restructuring to form discrete Ni-Sn sites. Computational modeling confirmed favorable energetics for Ru-Sn segregation and Ni-Sn formation at submonolayer Sn incorporation. To address stainless steel leaching, reactor walls were treated with an inert silica coating by chemical vapor deposition. With leaching reduced, stable Ru-Sn/AC performance was observed that resulted in a molar yield of 71% BDO and 15% tetrahydrofuran for 96 h of time on stream. Postreaction catalyst characterization confirmed low levels of Ni and Cr deposition, although early-stage islanding of Ni-Sn will likely be problematic for industrially relevant time scales (i.e., thousands of hours). Overall, these results (i) demonstrate the performance of Ru-Sn/AC for aqueous phase succinic acid reduction, (ii) provide insight into the Ru-Sn bimetallic structure and deactivation in the presence of leached Ni, and (iii) underscore the importance of compatible reactor metallurgy and durable catalysts.
| Original language | English |
|---|---|
| Pages (from-to) | 6207-6219 |
| Number of pages | 13 |
| Journal | ACS Catalysis |
| Volume | 7 |
| Issue number | 9 |
| DOIs | |
| State | Published - Sep 1 2017 |
Funding
We thank the U.S. Department of Energy (DOE) Bioenergy Technologies Office for funding this work via Contract No. DE-AC36-08GO28308 at the National Renewable Energy Laboratory. In addition, this work was performed in collaboration with the Chemical Catalysis for Bioenergy Consortium (ChemCatBio), a member of the Energy Materials Network (EMN), and was supported by the DOE Bioenergy Technologies Office under Contract No. DE-AC05-00OR22725 with the ORNL and Contract No. DE-AC36-08- GO28308 with the NREL. STEM experiments were performed using instrumentation (FEI Talos F200X STEM) provided by the DOE, Office of Nuclear Energy, Fuel Cycle R&D Program, and the Nuclear Science User Facilities. The computational work was supported in part by the Consortium for Computational Physics and Chemistry funded by the DOE’s Bioenergy Technologies Office (DE-AC36-08GO28308). The authors are grateful for supercomputer time on Stampede provided by the Texas Advanced Computing Center (TACC) under the National Science Foundation Extreme Science and Engineering Discovery Grant MCB09159 and the NREL Computational Sciences Center, which is supported by the DOE Office of Energy Efficiency and Renewable Energy under Contract No. DE-AC36-08GO28308. Support for K.X.S. was provided by the NREL’s intellectual property licensing program. We also thank Glenn Teeter at the NREL for his assistance with XPS analysis. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes.
| Funders | Funder number |
|---|---|
| Chemical Catalysis for Bioenergy Consortium | |
| Energy Materials Network | |
| National Science Foundation Extreme Science and Engineering Discovery | MCB09159 |
| Texas Advanced Computing Center | |
| U.S. Department of Energy | |
| Office of Energy Efficiency and Renewable Energy | |
| Office of Nuclear Energy | |
| Oak Ridge National Laboratory | DE-AC36-08- GO28308 |
| National Renewable Energy Laboratory | |
| Bioenergy Technologies Office | DE-AC05-00OR22725, DE-AC36-08GO28308 |
Keywords
- Ru-Sn/AC
- biobased chemical
- catalyst stability
- leaching
- lignocellulose
- restructuring