TY - JOUR

T1 - Mechanism of CaO catalyst deactivation with unconventional monitoring method for glycerol carbonate production via transesterification of glycerol with dimethyl carbonate

AU - Praikaew, Wanichaya

AU - Kiatkittipong , Worapon

AU - Aiouache, Farid

AU - Najdanovic-Visak, Vesna

AU - Termtanun, Mutsee

AU - Wei Lim, Jun

AU - Shiung Lam, Su

AU - Kiatkittipong, Kunlanan

AU - Laosiripojana, Navadol

AU - Boonyasuwat, Sunya

AU - Assabumrungrat, Suttichai

N1 - This is the peer reviewed version of the following article: Chrisman, J. J., Praikaew, W, Kiatkittipong, W, Aiouache, F, et al. Mechanism of CaO catalyst deactivation with unconventional monitoring method for glycerol carbonate production via transesterification of glycerol with dimethyl carbonate. Int J Energy Res. 2022; 46 (2): 1646- 1658. doi:10.1002/er.7281 which has been published in final form at https://onlinelibrary.wiley.com/doi/10.1002/er.7281 This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.

PY - 2022/2/28

Y1 - 2022/2/28

N2 - Glycerol carbonate (GC) was synthesized by transesterification of glycerol with dimethyl carbonate (DMC) using calcium oxide (CaO) derived from eggshell as a catalyst. The best results of 96% glycerol conversion and 94% GC yield were achieved under the following reaction conditions: 0.08 mole ratio of CaO to glycerol, 1:2.5 mole ratio of glycerol to DMC, 60 degrees C reaction temperature, and 3 hours reaction time. As expected, CaO showed deteriorated catalytic performance when recycling as observed by a rapid decrease in GC yield. This research showed that the active CaO phase first was converted to calcium methoxide (Ca[OCH3](2)) and calcium diglyceroxide (Ca[C3H7O3](2)) and finally to carbonate phase (CaCO3) which can be confirmed by XRD patterns. According to the phase transformation, the basicity decreased from 0.482 mmol/g to 0.023 mmol/g, and basic strength altered from strong basic strength (15.0 < H_ < 18.4) to weak basic strength (7.2 < H_ < 9.8), resulting in the lower catalytic activity of the consecutive runs. Despite the fact that the GC selectivity was almost 100%, the reaction products (methanol and GC) were not obtained in their stoichiometric ratio and their extents corresponded with that of the catalyst phase transformation to CaCO3. The mechanism of CaO catalyzed transesterification based on the condensation reaction of glycerol and catalyst was proposed, and in situ formation of water-derivative species was hypothesized as a cause of CaO transformation. CaO could react with DMC and water, generating methanol and CaCO3. This enabled unconventional monitoring of catalyst deactivation by checking if the mole ratio of methanol to GC was higher than 2:1 of its reaction stoichiometric ratio. It was also demonstrated that calcination of post-run catalyst at 900 degrees C to CaO exhibited almost constant catalytic activity, and the mole ratio of methanol to GC was constant at its reaction stoichiometry (2:1) for at least 4 times use.

AB - Glycerol carbonate (GC) was synthesized by transesterification of glycerol with dimethyl carbonate (DMC) using calcium oxide (CaO) derived from eggshell as a catalyst. The best results of 96% glycerol conversion and 94% GC yield were achieved under the following reaction conditions: 0.08 mole ratio of CaO to glycerol, 1:2.5 mole ratio of glycerol to DMC, 60 degrees C reaction temperature, and 3 hours reaction time. As expected, CaO showed deteriorated catalytic performance when recycling as observed by a rapid decrease in GC yield. This research showed that the active CaO phase first was converted to calcium methoxide (Ca[OCH3](2)) and calcium diglyceroxide (Ca[C3H7O3](2)) and finally to carbonate phase (CaCO3) which can be confirmed by XRD patterns. According to the phase transformation, the basicity decreased from 0.482 mmol/g to 0.023 mmol/g, and basic strength altered from strong basic strength (15.0 < H_ < 18.4) to weak basic strength (7.2 < H_ < 9.8), resulting in the lower catalytic activity of the consecutive runs. Despite the fact that the GC selectivity was almost 100%, the reaction products (methanol and GC) were not obtained in their stoichiometric ratio and their extents corresponded with that of the catalyst phase transformation to CaCO3. The mechanism of CaO catalyzed transesterification based on the condensation reaction of glycerol and catalyst was proposed, and in situ formation of water-derivative species was hypothesized as a cause of CaO transformation. CaO could react with DMC and water, generating methanol and CaCO3. This enabled unconventional monitoring of catalyst deactivation by checking if the mole ratio of methanol to GC was higher than 2:1 of its reaction stoichiometric ratio. It was also demonstrated that calcination of post-run catalyst at 900 degrees C to CaO exhibited almost constant catalytic activity, and the mole ratio of methanol to GC was constant at its reaction stoichiometry (2:1) for at least 4 times use.

KW - biomass waste derived catalyst

KW - catalyst deactivation

KW - catalytic activity

KW - deactivation mechanism

KW - fatty acid methyl ester

KW - glycerol carbonate production

U2 - 10.1002/er.7281

DO - 10.1002/er.7281

M3 - Journal article

VL - 46

SP - 1646

EP - 1658

JO - International Journal of Energy Research

JF - International Journal of Energy Research

SN - 0363-907X

IS - 2

ER -