Efficient Propylene Carbonate Synthesis from Urea and Propylene Glycol over Calcium Oxide-Magnesium Oxide Catalysts

Kavisha Dang; Navneet Kumar; Vimal Chandra Srivastava; Jinsub Park; Mu Naushad

doi:10.3390/ma16020735

Efficient Propylene Carbonate Synthesis from Urea and Propylene Glycol over Calcium Oxide-Magnesium Oxide Catalysts

Materials (Basel). 2023 Jan 11;16(2):735. doi: 10.3390/ma16020735.

Authors

Kavisha Dang¹, Navneet Kumar², Vimal Chandra Srivastava¹, Jinsub Park², Mu Naushad³

Affiliations

¹ Department of Chemical Engineering, Indian Institute of Technology Roorkee, Roorkee 247667, India.
² Department of Electronics Engineering, Hanyang University, Seoul 04763, Republic of Korea.
³ Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.

Abstract

A series of calcium oxide-magnesium oxide (CaO-MgO) catalysts were prepared under the effects of different precipitating agents and using varied Mg/Ca ratios. The physiochemical characteristics of the prepared catalysts were analyzed using XRD, FE-SEM, BET, FTIR, and TG/DTA techniques. Quantification of basic active sites present on the surface of the CaO-MgO catalysts was carried out using the Hammett indicator method. The as-prepared mixed oxide samples were tested for propylene carbonate (PC) synthesis through the alcoholysis of urea with propylene glycol (PG). The effects of the catalyst composition, catalyst dose, reaction temperature, and contact time on the PC yield and selectivity were investigated. The maximum PC yield of 96%, with high PC selectivity of 99% and a urea conversion rate of 96%, was attained at 160 °C using CaO-MgO catalysts prepared using a Mg/Ca ratio of 1 and Na₂CO₃ as a precipitating agent. The best-performing catalysts also exhibited good reusability without any significant loss in PC selectivity. It is expected that the present study will provide useful information on the suitability of different precipitating agents with respect to the catalytic properties of the oxides of Ca and Mg and their application in the synthesis of organic carbonates.

Keywords: alcoholysis; cyclic carbonates; propane-1,2-diol; propylene carbonate; urea.

Grants and funding

Corresponding authors are thankful to the Process Development Wastewater Management in Petrochemical Industries, India, grant no. MCF-1349_CHD and the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2021R1A4A1052085) for providing financial help in carrying out this work. The author (Mu. Naushad) is grateful to the Researchers Supporting Project number (RSP2023R8), King Saud University, Riyadh, Saudi Arabia, for financial support.