Efficient Conversion of Bio‐Lactic Acid to 2,3‐Pentanedione on Cesium‐Doped Hydroxyapatite Catalysts with Balanced Acid–Base Sites

Abstract

We report the design and synthesis of cesium‐doped hydroxyapatite for direct and high‐yield conversion of biobased lactic acid to 2,3‐pentanedione (72.3 %). Cs species derived from CsNO3 at high temperature of calcination is introduced into the hydroxyapatite structure to regulate its acid–base properties. It is found that a balance of acid–base chemistry favors the condensation of lactic acid to 2,3‐pentanedione. As a result, the undesired reactions such as lactic acid dehydration, decarbonylation, and coking are suppressed. Instead, a concerted catalysis between surface basic site and acidic site for lactic acid condensation to 2,3‐pentanedione dominates on the cesium‐doped hydroxyapatite catalyst, leading to a highly selective process for direct conversion of bio‐lactic acid to 2,3‐pentanedione.

Biodiesel production from rapeseed oil and low free fatty acid waste cooking oil using a cesium modified natural phosphate catalyst

“…2 shows that only the characteristic peaks of the apatite structure were detected, suggesting that the CsCl precursor was thermally decomposed and that the cesium species were partially incorporated into the apatite structure and regulate its acid-base properties, thus resulting in the generation of different catalytically active sites. 40 Furthermore, the XRD pattern of calcined sample shows the disappearance of diffractions peaks relative to calcite and quartz. This suggests that the quartz (SiO 2 ) was either transformed into amorphous silica or it was incorporated into the calcium phosphate lattice resulting in a silicon-substituted apatite, 27 whereas the disappearance of the diffraction peaks of the calcite suggests that this phase was totally decomposed during the thermal treatment.…”

Vapor-Phase Deoxygenation of Lactic Acid to Biopropionic Acid over Dispersant-Enhanced Molybdenum Oxide Catalyst

“…Similarly, propionic acid yield (53–61%) also retained an excellent stability with time on stream. In terms of PA yield, the result was by far better than previous reports. , It is also noted that the LA feed flow rate of 10 mL/h (corresponding contact time = 22.5 g·h·mol –1 ) used in this work is far more than previous reports on LA conversion into other chemicals such as acrylic acid and 2,3-pentanedione, indicating that deoxygenation reaction of LA is faster than other conversions of LA, and rich active sites for deoxygenation of LA exist on the surface of the catalyst. ,,,− In order to fully understand the stability of active sites of catalyst at low LA conversion (∼30%), the catalyst was reduced from 0.5 to 0.16 g and remained with the LA feed flow rate (shown in Figure S1). It was found that catalyst still offered an excellent stability around 80 h on stream.…”

Bio‐Acrylates Production: Recent Catalytic Advances and Perspectives of the Use of Lactic Acid and Their Derivates

“…LA can be converted, among others, to acetaldehyde, 1,2‐propanediol, 2,3‐pentanedione or it may undergo dimerization to lactide . However, the conversion of LA to AA is the most widely studied route.…”