Hydrogenation of ethyl lactate over ruthenium catalysts in an additive-free catalytic system

Abstract

The hydrogenation of biomass-derived ethyl lactate was studied over several ruthenium catalysts (Ru/TiO 2 , Ru/SiO 2 , Ru/c-Al 2 O 3 , Ru/NaY and Ru/C), with the intent of developing a simple and additive-free catalytic system. The catalytic performance is dependent on the nature of the support. Ru/SiO 2 was found to be an efficient catalyst for the hydrogenation of ethyl lactate to 1,2-propanediol (1,2-PDO). Parametric studies show that the reaction temperature, hydrogen pressure and catalyst amount can significantly influence the catalytic performance. Under optimal reaction conditions (433 K, 5 MPa), high yield of 1,2-PDO (82.1%) was obtained without the introduction of any additives. Form a practical point of view, this study may open the way to a new approach for the production of 1,2-PDO.

Production of Lactic Acid/Lactates from Biomass and Their Catalytic Transformations to Commodities

“…Lactic acid or lactates can be converted to propylene glycol in the liquid phase over Ru catalysts with or without any promoters − ,,,− ,,,,, as well as over Co/SiO 2 or over Cu catalysts in the vapor phase. ,,,− Pd, Ni, and Fe on SiO 2 as catalysts were studied by Huang et al, and Co/SiO 2 was investigated by Huang et al and Xue et al , A novel method of lactic acid hydrogenation by syngas over Au/ZrO 2 was discovered by Lei et al All catalysts reported in the literature for lactic acid hydrogenation and lactate hydrogenolysis are summarized and presented respectively in Tables and Table .…”

“…The conversion of ethyl lactate was up to 98%, and the selectivity for 1,2-PDO was above 95% (10 h reaction time) (Table , entry 1) . Feng et al made an attempt to hydrogenate ethyl lactate over Ru catalysts supported on TiO 2 , SiO 2 , γ-Al 2 O 3 , NaY, and active carbon without addition of any promoters to simplify the catalyst preparation and thereby the cost of the process and found Ru/SiO 2 to be an efficient catalyst (Table , entry 4). , …”

“…Nevertheless, Ru/C is not very active with a small Ru particle size, which is probably attributable to different surface features of the active carbon. SiO 2 was considered to be a superior support for the hydrogenation of ethyl lactate to 1,2-PDO, exhibiting satisfying activity and the highest selectivity for 1,2-PDO with an 82.1% yield of 1,2-PDO . Figure displays, however, even higher conversion for the same reaction time in the case of Ru/TiO 2 .…”

“…The aim of this review is to describe the research in the production of lactic acid from biomass and its transformation to commodity chemicals mainly since 2002. The following reactions will be discussed in detail: catalytic production of lactic acid or alkyl lactates using homogeneous and heterogeneous catalysts (section 2), catalytic transformation of lactic acid or alkyl lactates via hydrogenation to 1,2-propanediol (propylene glycol), − dehydrogenation to pyruvic acid, − dehydration to acrylic acid, − decarbonylation and decarboxylation to acetaldehyde, , condensation of lactic acid to 2,3-pentanedione, − …”

Bio-Based Chemicals from Renewable Biomass for Integrated Biorefineries

“…The addition of some additives such as boron, tin, and iron to Ru-based catalysts has been reported in the literature [265]. Feng et al [266] hydrogenated ethyl lactate with Ru catalysts over TiO 2 , SiO 2 , Al 2 O 3 , NaY, and active carbon and found Ru/SiO 2 to be an effective catalyst [266][267][268]. Xu et al [264] tested the Co/SiO 2 catalyst for liquid-phase hydrogenation of ethyl lactate.…”