Magnetically Induced Catalytic Reduction of Biomass-Derived Oxygenated Compounds in Water

The development of energetically efficient processes for the aqueous reduction of biomass-derived compounds into chemicals is key for the optimal transformation of biomass. Herein we report an early example of the reduction of biomass-derived oxygenated compounds in water by magnetically induced catalysis. Non-coated and carbon-coated core–shell FeCo@Ni magnetic nanoparticles were used as the heating agent and the catalyst simultaneously. In this way it was possible to control the product distribution by adjusting the field amplitude applied during the magnetic catalysis, opening a precedent for this type of catalysis. Finally, the encapsulation of the magnetic nanoparticles in carbon (FeCo@Ni@C) strongly improved the stability of the magnetic catalyst in solution, making its reuse possible up to at least eight times in dioxane and four times in water.


S5. SAR
SAR has been measured by calorimetry. An air-tight tube containing about 10 mg of heating agents dispersed in 0.5 ml of mesitylene was filled under inert atmosphere. The tube was then placed in a calorimeter containing 2.5 ml of deionized water, the temperature of which was monitored during the experiment. The calorimeter was exposed to an alternative magnetic field for a time varying between 5 and 20s so that the temperature rise never exceeded 20°C. The temperature rise at the end of the magnetic field application was always measured after shaking the calorimeter to ensure the temperature homogeneity, which was measured by two probes (at the top and the bottom of the calorimeter). The temperature rise was determined after this process from the mean slope of the ΔT/Δt function. Then the raw SAR values were calculated using the expression: The raw SAR values were corrected from the calorimeter losses, which were previously calibrated. For the calibration, a sample containing nanoparticles displaying moderate SAR was exposed for different time periods to an alternating magnetic field of 47 mT, 100 kHz.
For each time, the SAR of the sample was measured. The SAR measured for an exposure time of 5s is considered as the "real" SAR (no losses). For longer exposure times, the difference between the measured SAR and the "real" SAR allows the determination of a corrective factor. The calibration curve is displayed below.
For each exposure time, the SAR was measured several times to ensure reproducibility.
For the samples presented in this article, the measurement times were often comprised between 20 and 30s. Temperature monitoring has been done using a thermocouple disposed 8 in a quartz cannula disposed in the centre of the catalytic bed surrounded by the magnetic field inductor. Temperature range is 0-1300°C.                  S9. Table S1. State-of-the-art catalysts for the reduction of HMF.

S12. Measurement of the magnetic field amplitudes generated by the alternating magnetic field (AMF)
Given the operating mode of the AMF used in this work, which heat conductive or magnetic samples by induction, any sensor that presents metallic parts would be heated when trying to measure the magnetic field generated by the AFM, affecting the sensitivity of the sensor (or melting/deteriorating the sensor). In order to avoid these drawbacks, we decided to use a one loop pick-up coil made with a small diameter Cu wire of 90 µm to reduce heating by eddy currents as much as possible ( Figure S34) For the designed pick-up coil sensor and a frequency of 328.9 kHz (working frequency of the AMF with the 6-turn field-generating coil), the relationship of magnetic induction with the voltage in the coil is: Then, the magnetic induction in vacuum and the magnetic field (dividing the magnetic induction by ) can be obtained as a function of the voltage induced in the pick-up coil: It is worth to mention that this calculation of the magnetic field is only valid if the magnetic flux is sinusoidal. If the magnetic field is not sinusoidal, it would be necessary to perform the integral of the signal obtained in the pick-up coil and divide it by the loop area and the vacuum permeability in order to get the magnetic field (this integral could be done with an analog integrator or done with a math program). In the measurements made in this AMF, the voltage obtained in the pickup coil sensor was sinusoidal, so we could determine the induction and magnetic field proportional to the peak voltage obtained in the pick-up coil ( Figure S35).