Catalytic Transfer Hydrogenolysis of Bio-Polyols to Renewable Chemicals over Bimetallic PtPd/C Catalysts: Size-Dependent Activity and Selectivity

Abstract

Most industrial hydrogenation processes are conducted under elevated temperature and pressure. Catalytic transfer hydrogenation/hydrogenolysis, in the absence of externally added hydrogen, is known to be much more energy efficient and atom economical. However, the multifunctional nature of catalyst structure on simultaneous hydrogen generation, hydrogen transfer, and hydrogenation reactions is largely unexplored. We reported a design principle and size-dependent behavior of bimetallic PtPd/C catalysts for transfer hydrogenolysis of bioderived polyols to renewable glycols as an illustrative example. The central finding in this work is that, while kinetics of partial dehydrogenation (C–H cleavage) display size insensitivity, reforming (C–C cleavage) and hydrogenolysis (C–O cleavage) reactions show strong size-determining activity and selectivity in the range of 2.0 to 5.3 nm. The synergistic PtPd/C catalysts lead to a remarkable selectivity of 87% for value-added glycols and derivatives even under an inert atmosphere. The outcome from this fundamental study will provide insights into the structural design of next-generation solid catalysts for energy efficient hydrogenation processes.

Hydrogenolysis of Glycerol to Propylene Glycol: Energy, Tech-Economic, and Environmental Studies

“…The mass flow rates for PG, EG, acetol, and PrOH are 893.4 kg/h, 89.3 kg/h, 14.1 kg/h, and 12.3 kg/h, respectively, while CTH of glycerol leads to 606.3 kg/h, 42. kg/h, and 116.6 kg/h for those products. The product distribution (carbon-based selectivity, 58.7%) ( Zhang et al, 2020a ; Yin et al, 2020 ) for the two processes has also been presented in inset of Figure 4 . It is found that, for CHDO process, the main products include PG (86.5%) and EG (10.6%), with trace amounts of acetol and PrOH as co-products.…”

“…Reaction parameters such as temperatures, pressures, and catalyst loading have been studied experimentally in our laboratory, as already reported previously ( Jin et al, 2019a ; Jin et al, 2019b ; Zhang et al, 2020a ; Zhang et al, 2020b ; Yin et al, 2020 ). Conversion and selectivity data obtained from those reports were used as input for determination of configuration of reactor unit in simulation ( Von Held Soares et al, 2017 ; Zhang et al, 2020a ; Yin et al, 2020 ). As shown in Table 1 , the reactions considered for this work include 1) dehydrogenation of EtOH, 2) dehydration of glycerol, and (3–4) hydrogenolysis of glycerol.…”

“…Both CHDO and CTH plant studied in this work consist of three main units: pretreatment unit, hydrogenolysis unit where glycerol is converted into PG and other co-products, and separation and purification unit. In this work, reaction results over Ni/Cu/TiO 2 catalyst were used for simulation of CHDO process ( Cai et al, 2018 ; Jin et al, 2019a ; Jin et al, 2019b ; Xia et al, 2020 ; Yin et al, 2020 ). Ni/Cu/TiO 2 catalyst was selected for CHDO process because it displays leading performances in conversion and PG selectivity in literature.…”

“…Catalytic transfer hydrogenolysis (CTH), which takes use of renewable H-donors in liquid medium, is considered as one of the most economically and environmentally beneficial technique to substitute conventional hydrogenolysis processes (CHDO, Figure 1 ). ( Jin et al, 2019b ; Zhang et al, 2020a ; Yin et al, 2020 ; Nie et al, 2021 ). Much milder reaction temperatures, higher intrinsic hydrogenolysis rates in aqueous medium, and lower operating pressures in the absence of externally added H 2 make CTH processes more energy and atom efficient compared with CHDO processes.…”

Ru on N‐doped Carbon for the Selective Hydrogenolysis of Sugars and Sugar Alcohols

“…To enhance selectivity, many monometallic catalysts based on Cu, Ni, Pt or Ru were developed and tested in combination with a homogeneous base [8–14] . Additionally, recent research focused on the development of bimetallic catalysts to facilitate reactions with the addition of a solid base, without external hydrogen pressure or to further enhance selectivity [15–24] …”