A subscription to JoVE is required to view this content. Sign in or start your free trial.
* These authors contributed equally
Membrane reactors enable hydrogenation in ambient conditions without direct H2 input. We can track the hydrogen production and utilization in these systems using atmospheric mass spectrometry (atm-MS) and gas chromatography mass spectrometry (GC-MS).
Industrial hydrogenation consumes ~11 Mt of fossil-derived H2 gas yearly. Our group invented a membrane reactor to bypass the need to use H2 gas for hydrogenation chemistry. The membrane reactor sources hydrogen from water and drives reactions using renewable electricity. In this reactor, a thin piece of Pd separates an electrochemical hydrogen production compartment from a chemical hydrogenation compartment. The Pd in the membrane reactor acts as (i) a hydrogen-selective membrane, (ii) a cathode, and (iii) a catalyst for hydrogenation. Herein, we report the use of atmospheric mass spectrometry (atm-MS) and gas chromatography mass spectrometry (GC-MS) to demonstrate that an applied electrochemical bias across a Pd membrane enables efficient hydrogenation without direct H2 input in a membrane reactor. With atm-MS, we measured a hydrogen permeation of 73%, which enabled the hydrogenation of propiophenone to propylbenzene with 100% selectivity, as measured by GC-MS. In contrast to conventional electrochemical hydrogenation, which is limited to low concentrations of starting material dissolved in a protic electrolyte, the physical separation of hydrogen production from utilization in the membrane reactor enables hydrogenation in any solvent or at any concentration. The use of high concentrations and a wide range of solvents is particularly important for reactor scalability and future commercialization.
Thermochemical hydrogenation reactions are used in ~20% of all chemical synthesis1. These reactions require large quantities of H2 gas, which are usually derived from fossil fuels, temperatures between 150 °C and 600 °C, and pressures up to 200 atm2. Electrochemical hydrogenation is an appealing way to bypass these requirements and to drive hydrogenation reactions using water and renewable electricity3. For conventional electrochemical hydrogenation, an unsaturated feedstock is dissolved in a protic electrolyte in an electrochemical cell. When a potential is applied to the cel....
1. Pd rolling
Atm-MS is used to measure the ionic current of the hydrogen that is produced in the membrane reactor. We can use these measurements to quantify how much hydrogen permeates through the Pd membrane during electrolysis. First, the hydrogen evolving from the hydrogenation compartment is measured (Figure 3, left of the dotted lines). When the signal reaches a steady state, the channel is switched to the electrochemical compartment. The H2 gas evolving from the electrochemical compartme.......
The Pd membrane enables hydrogen permeation and chemical hydrogenation. The preparation of this membrane is, therefore, important to the efficacy of the membrane reactor. The Pd membrane size, crystallography, and surface are tuned to improve the experimental results. Although Pd metal can evolve hydrogen at any thickness, the Pd membranes are rolled to 25 µm. This standardization of membrane thickness ensures that the time it takes for hydrogen to permeate through the membrane is constant for all the experiments. M.......
We are grateful to the Canadian Natural Sciences and Engineering Research Council (RGPIN-2018-06748), the Canadian Foundation for Innovation (229288), the Canadian Institute for Advanced Research (BSE-BERL-162173), and Canada Research Chairs for financial support. This research was undertaken thanks in part to funding from the Canada First Research Excellence Fund, Quantum Materials and Future Technologies Program. We thank Ben Herring at the UBC Shared Instrument Facility for assistance with the GC-MS instrument and method development. We thank Dr. Monika Stolar for contributions to the development and editing of this manuscript. Finally, we thank the entire Berlingu....
Name | Company | Catalog Number | Comments |
Ag/AgCl Reference Electrode | BASi research products | MW-2021 | Reference electrode |
Analytical Balance | Cole-Parmer | RK-11219-03 | Instrument |
Atmospheric Mass Spectrometer | ESS CatalySys | NA | Instrument |
Bench Power Supply | Newark | 1550 | Instrument |
Conductive Copper Foil Electrical Tape | McMaster Carr | 76555A711 | Electrochemical cell assembly |
Dichloromethane | Sigma Aldrich | 270997 | Reagent |
Electric Rolling Press with Dual Micrometer | MTI Corporation | MR100A | Equipment |
Electrochemical glass H-cell | University of British Columbia glass blowing | NA | Electrochemical cell assembly |
ESS catalysis QUADSTAR | ESS CatalySys | NA | Software |
Ethanol | Sigma Aldrich | 493511 | Reagent |
Flat Rolling Mill | Pepetolls | 18700A | Equipment |
Gas Chromatography Mass Spectrometer | Agilent | NA | Instrument |
GC-MS vial | Agilent | 5067-0205 | Vial for GC-MS |
Hexanes | Sigma Aldrich | 1.0706 | Reagent |
Hydrochloric Acid | Sigma Aldrich | 258148 | Reagent |
Hydrogen peroxide solution (30% v/v) | Sigma Aldrich | H1009 | Reagent |
Isopropyl Alcohol | Sigma Aldrich | W292907 | Reagent |
Masshunter Aquisition Software | Agilent | G1617FA | Software |
Micropipette (100 µL - 1000 µL) | Gilson | F123602 | instrument |
Micropipette (20 µL - 200 µL) | Gilson | F123601 | Instrument |
Mitutoyo Digital Micrometer | Uline | H-2780 | Instrument |
Muffle Furnace | MTI Corporation | KSL-1100X | Equipment |
Nitric acid | Sigma Aldrich | 438073 | Reagent |
Nitrogen gas | Sigma Aldrich | 608661 | Reagent |
Palladium (II) Chloride | Sigma Aldrich | 520659 | Reagent |
Pd wafer bar, 1 oz, 99.95% | Silver Gold Bull. | NA | Reagent |
Platinum Auxiliary Electrode | BASi research products | MW-1032 | Anode |
Potentiostat | Metrohm | PGSTAT302N | Instrument |
Propiophenone | Sigma Aldrich | P51605 | Reagent |
Proton Exchange Membrane, Nafion 212 | Fuel cell store | NA | Electrochemical cell assembly |
Sulfuric acid | Sigma Aldrich | 258105 | Reagent |
This article has been published
Video Coming Soon
ABOUT JoVE
Copyright © 2024 MyJoVE Corporation. All rights reserved