Catalytic dehydration of lactic acid to acrylic acid over sulfate catalysts

Abstract

The production of acrylates from biomass-originated lactic acid is of extraordinary importance to overcome the increasing worldwide shortage of petroleum. In this work, the catalytic dehydration of lactic acid to acrylic acid was carried out over calcium sulfate catalyst with cupric sulfate and phosphates as promoters. The mass ratio of m(CaSO 4 )/m(CuSO 4 )/m(Na 2 HPO 4 )/m(KH 2 PO 4 ) is 150.0:13.8:2.5:1.2. In the dehydration of lactic acid, effects of carrier gas, calcination temperature for catalyst, concentration of lactic acid as well as contact time are discussed in detail. With carbon dioxide as carrier gas, the highest acrylic acid yield of 63.7% is achieved from 26 wt.% lactic acid at 330 • C and 88 s contact time.La production des acrylatesà partir d'acide lactique issu de biomasse est d'une extrême importance compte tenu du manque croissant de pétrole dans le monde. Dans ce travail, la déshydratation catalytique de l'acide lactique en acide acrylique aété effectuée sur un catalyseur de sulfate de calcium avec du sulfate cuprique et des phosphates comme promoteurs. Les rapports de masse de m(CaSO 4 ), m(CuSO 4 ), m(Na 2 HPO 4 ), m(KH 2 PO 4 ) sont de 150,0, 13,8, 2,5 et 1,2, respectivement. Dans la déshydratation de l'acide lactique, les effets du gaz porteur, de la température de calcination du catalyseur, de la concentration de l'acide lactique ainsi que du temps de contact sont examinés en détail. Avec le dioxyde de carbone comme gaz transporteur, le rendement en acide acrylique le plusélevé obtenu est de 63,7%,à partir d'acide lactiqueà 26% massique, 330 • C et un temps de contact de 88 secondes.

Deactivation behavior of alkali-metal zeolites in the dehydration of lactic acid to acrylic acid

“…Similar to other carboxylic acids, decarboxylation is enabled by the nucleophilic activation of the carboxylic group. Besides redox-active metal sites such as Fe or Ni [9,10], only strong nucleophilic catalysts accelerate this reaction [11,12]. The mechanism of the dehydration of LA to AA is not yet understood in detail, although a postulation for the intermediate species was made by Gunter et al [13] for the reaction over phosphate catalysts, which could be verified by other groups using infrared and Raman spectroscopy [14].…”

A new route for the synthesis of methacrylic acid from 2-methyl-1,3-propanediol by integrating biotransformation and catalytic dehydration

“…4 Also, dehydration of lactic acid to obtain acrylic acid has been studied, 5,6 but the 65 product yield was too low for commercial application. A similar process for the production of methacrylic acid would require 3-hydroxy-2-methyl propionic acid (3H2MPA, isohydroxybutyric acid) as the substrate.…”

Highly efficient and robust Mg0.388Al2.408O4 catalyst for gas-phase decarbonylation of lactic acid to acetaldehyde

“…The contact time of reactant over the catalyst is around 0.5 s, and the contact time is estimated according to Eq. (1) [32,49]. The liquid products are condensed using ice-water bath and analyzed off-line using a SP-6890 gas chromatograph with a FFAP capillary column connected to a FID.…”