2‐(N‐Methylbenzyl)pyridine: A Potential Liquid Organic Hydrogen Carrier with Fast H₂ Release and Stable Activity in Consecutive Cycles

Abstract

The liquid organic hydrogen carrier (LOHC) 2-(N-methylbenzyl)pyridine (MBP) shows good potential for H storage based on reversible hydrogenation and dehydrogenation, with an H storage density of 6.15 wt %. This material and the corresponding perhydro product (H -MBP) are liquids at room temperature. Remarkably, H release is much faster from H -MBP over Pd/C than from the benchmark perhydro benzyltoluene over Pt/C at lower temperatures than 270 °C, owing to the addition of N atom into the benzene ring. Since this positive effect is unfavorable to the hydrogenation reaction, more Ru/Al O catalyst or prolonged reaction time must be applied for complete H storage. Experiments with repeated hydrogenation-dehydrogenation cycles reveal that reversible H storage and release are possible without degradation of the MBP/H -MBP pair. The prepared MBP satisfies the requirements for chemical stability, handling properties, and cytotoxicity testing.

Homogeneous Catalysis for Sustainable Energy: Hydrogen and Methanol Economies, Fuels from Biomass, and Related Topics

“…In a similar direction, LOHC based on 2-[( N -methylcyclohexyl)methyl]piperidine/2-( N -methylbenzyl)pyridine with a hydrogen storage capacity of 6.1 wt % was reported by Suh and Park. 195 Kempe discovered an LOHC based on phenazine (PHZ) that can be synthesized from cyclohexane-1,2-diol obtained from hydrogenolysis of lignin. 196 With the use of a bimetallic catalyst, Pd 2 Ru@SiCN, PHZ was hydrogenated to form 14H-phenazine, making it a hydrogen storage material of 7.2 wt %.…”

Liquid Organic Hydrogen Carriers or Organic Liquid Hydrides: 40 Years of History

“…Apart from the well-known pairs that were already presented, new couples appeared in the very recent literature. Among the most promising molecules that can store hydrogen appears n-(methylbenzyl)pyridine, liquid in the range of use and less viscous than DBT [37]. A list of alkyl-indoles was also evaluated in the Sustainable Energy Laboratory of Wuhan with several papers that are reported in the review written by Rao et al [29].…”

Dehydrogenation of 2-[(n-Methylcyclohexyl)Methyl]Piperidine over Mesoporous Pd-Al2O3 Catalysts Prepared by Solvent Deficient Precipitation: Influence of Calcination Conditions

“…The reduced MPdA catalyst was tested for the dehydrogenation of H 12 -MBP in a batch reactor (volume: 90 cm 3 ) described previously [9,12,13]. In a typical experiment, H 12 -MBP of 7.3 mmol was added dropwise to the MPdA catalyst pre-loaded at the bottom of the reactor vessel, where the catalyst weight was varied to obtain a desired metal-to-reactant (M/R) ratio.…”

“…Among them, hydrogen storage by means of It is well known that supported Pd catalysts are efficient in the dehydrogenation of N-heterocyclic LOHC compounds; for example, alumina and silica supported Pd catalysts have been successfully applied for the dehydrogenation of dodecahydro-N-ethylcarbazole [14][15][16][17], while 5 wt% Pd/Al 2 O 3 was used for the dehydrogenation of octahydro-N-ethylindole [18] and octahydro-2-methylindole [19]. Furthermore, Pd/C and Pd/Al 2 O 3 catalysts have demonstrated higher H 12 -MBP dehydrogenation capabilities compared to those of their Pt counter catalysts [12]. However, the Pd/C catalyst fails to retain its dehydrogenation efficiency compared to Pd/Al 2 O 3 (showing a slight activity loss) in stability tests because of the accumulation of Pd particles.…”