Selective Synthesis of 1‐O‐Alkyl(poly)glycerol Ethers by Catalytic Reductive Alkylation of Carboxylic Acids with a Recyclable Catalytic System

Abstract

(Poly)glycerol monoethers were synthesized in good yield and selectivity by the catalytic reductive alkylation of glycerol, diglycerol, and triglycerol with readily available, cheap and/or bio-sourced carboxylic acids. The reaction was catalyzed by 1 mol % of Pd/C under 50 bar H(2) using an acid ion-exchange resin as a recyclable cocatalyst. The catalytic system was recycled several times, and a mechanism is proposed for this transformation.

Glycerol Ether Synthesis: A Bench Test for Green Chemistry Concepts and Technologies

“…Lemaire et al 424 proposed a mechanism based on the reactivity of various substrates such as 1-propanol, 1,2-propanediol, and 1,3-propanediol. First, carboxylic acid I is activated by Amberlyst 35, which favors the addition of glycerol to give intermediate II after prototropy.…”

Synthesis of Biomass‐Derived Ethers for Use as Fuels and Lubricants

“…This method is therefore suitable for the selective synthesis of symmetrical or asymmetrical primary or secondary ethers. Reductive etherification of carbonyl compounds can also be performed using polyols such as glycerol to produce surfactants, fuel additives, and other value‐added products . Drawbacks of the reductive etherification synthesis are the requirement of hydrogen and the use of precious‐metal catalysts.…”

“…In addition to the synthesis of lubricant‐range ethers from biomass‐derived alcohols, reductive etherification was employed for the synthesis of glycerol ethers (Scheme b). Lemaire and co‐workers prepared glycerol ethers selectively via the reductive etherification of glycerol with aldehydes, ketones, carboxylic acids, methyl esters, and triglycerides . These reactions were performed with a combination of carbon‐supported Pd, H 2 , and an acid catalyst …”

“…The mechanism for glycerol etherification with a carboxylic acid in the presence of molecular hydrogen proposed by Lemaire and co‐workers is shown in Scheme . The major product is shown in green.…”

Transforming Methyl Levulinate into Biosurfactants and Biolubricants by Chemoselective Reductive Etherification with Fatty Alcohols

“…Reductive etherification of carbonyl compounds with alcohols over supported catalysts with metals such as platinum, palladium, or rhodium under hydrogen pressure is an interesting protocol to produce ethers from carbonyl compounds. In this reaction acetals, hemiacetals, and/or enol ethers, the formation of which requires acid catalysis, have been suggested as possible intermediates (Scheme ), and, in some cases, an additional acid is required as cocatalyst.…”