(547a) Catalytic Conversion of Glycerol to Value-Added Dicarbocxylic Acids: Experimental Studies and Process Simulation on Energy Requirement and Environmental Impact

Replacing fossil-based feedstocks with renewable ones is considered to be key for reducing carbon emission and environmental pollution. In this context, biomass as a renewable energy is very important for establishing environment-friendly chemical processes. Aqueous phase oxidation of bio-derived polyols and sugars of the is one of the most important ways for sustainable conversion of biomass to value-added chemicals. Dicarboxylic acids (DCA), including glucaric acid, tartronic acid, and oxalic acid, provide major building blocks for everyday products, such as renewable polymers, nylon fibers, and BPA-free plastics. Among these DCAs, tartronic acid is a high value-added chemical that is widely used as a pharmaceutical and anticorrosive protective agent, as well as for the monomer of biopolymers.

In the past decade, extensive work has been reported on tartronic acid synthesis from glycerol using supported metal catalysts. Noble catalysts show complete conversion of glycerol even under mild conditions (55-70℃, 0.1-0.7Mpa O₂). The major challenges associated with the oxidation of glycerol are the control of selectivity to the tartronic acid. Recently, the best results reported in the literature are optimization of reaction conditions on Au/HY (TOF: 40h^-1, S: 82%) [1], PdBi/C (TOF: 0.96h^-1, S: 93%) [2] and PtCe/C (TOF:< 1 h^-1, S:38%) [3] have shown good selectivity toward tartronic but poor oxidation activity. High price of noble metals but poor oxidation performances motivated us to design more active and cost-effective catalytic materials for selective tartronic acid synthesis. We recently reported bimetallic PtFe nanoparticles on CeO₂ support for glycerol oxidation in the aqueous phase under mild conditions (60-80℃，0.1Mpa O₂). [4] Compared with other catalysts, Pt-Fe/CeO₂ catalysts showed remarkable catalytic performance in forming tartronic acid (X: 100%，TOF: 20,978.2 ± 707.1 h^-1，S: 32%). In this work, we the structural-activity, selectivity and stability studies on bimetallic PtFe/CeO₂ catalysts for glycerol oxidation. Based on experimental work, we also carried out detailed process simulation on energy requirement and environmental impact for glycerol oxidation process in order to identify hot spot in process scheme. Furthermore, flow scheme, energy consumption and product quality were designed, simulated, and economically assessed using Aspen Plus. Key factors including composition of feedstocks, operating conditions for fixed bed reactor, separation requirement will be systematically studied to achieve optimal conditions for the production of tartronic acid. The outcome of this work will provide insights into future catalyst redesign and process development.

Reference

[1] J.Y. Cai, H. Ma, J.J. Zhang, Z.T. Du, Y.Z. Huang, J. Gao, J. Xu, Catalytic oxidation of glycerol to tartronic acid over Au/HY catalyst under mild conditions, Chin. J. Catal. 35 (2014) 1653–1660.

[2] H. Kimura, A. Kimura, I. Kokubo, T. Wakisaka, Y. Mitsuda, Palladium based multicomponent catalytic-systems for the alcohol to carboxylate oxidation reaction, Appl. Catal. A-Gen. 95 (1993) 143–169.

[3] H. Kimura, Oxidation assisted new reaction of glycerol, Polym. Adv. Technol. 12 (2001) 697–710.

[4] X. Jin , Meng Zhao , Wenjuan Yan , Chun Zeng , Pallavi Bobba , Prem S. Thapa , Bala Subramaniam , Raghunath V. Chaudhari , Anisotropic growth of PtFe nanoclusters induced by lattice-mismatch: Efficient catalysts for oxidation of biopolyols to carboxylic acid derivatives , Journal of Catalysis 337 (2016) 272–283