Replacing fossil feedstock with renewable sources became an attractive alternative in the chemical industry. For example, acrylic acid, a key monomer currently derived from crude oil, can be produced from lactic acid, which is readily available from fermentation.1 The conversion of lactic acid to acrylic acid can be achieved by catalytic dehydration. Modified zeolites and hydroxyapatite have been reported as efficient catalysts for this process.2,3 However, the role and nature of the active sites are still under debate, although it is generally accepted that Brønsted acid sites should be avoid. In this study, lanthanum phosphate (LaP) nano-rods were prepared using n-butylamine as the shape-directing-agent (SDA). The samples were extensively characterized and tested in the dehydration of LA to AA. Detailed characterization of LaP samples suggests that SDA not only affects the textural properties but also modifies the acid-base properties, which is critical in determining the catalytic performance. Moreover, it was found that weak Lewis acid sites are required to achieve high yield to AA. On the contrary, Brønsted acid sites undermine the selectivity towards AA, while strong basic sites result in catalyst deactivation due to carbon deposition. As shown in the figure, the long-term test suggests that a good stability can be achieved when the LaP catalyst is prepared using the optimal amount of SDA. References: (1) Ye, L.; Hudari, M. S. B.; Li, Z.; Wu, J. C. Biochem. Eng. J. 2014, 83, 16-21. (2) Zhang, J.; Zhao, Y.; Pan, M.; Feng, X.; Ji, W.; Au, C.-T. ACS Catal. 2010, 1, 32-41. (3) Ghantani, V. C.; Lomate, S. T.; Dongare, M. K.; Umbarkar, S. B. Green Chem. 2013, 15, 1211-1217

Conversion of lactic acid to bio-acrylic acid on lanthanum phosphate catalysts

251st National Meeting (2016)

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