Waste cooking oil as an efficient solvent for the production of urea precursor ammonium carbamate from carbon dioxide

Abstract Carbon sequestration and utilization are currently gaining attention as they help to reduce the emission of greenhouse gases in the atmosphere. This study explores the possibility of using carbon dioxide as a feedstock for the production of ammonium carbamate, a precursor molecule for urea production. Waste cooking oil was used as the indispensable nonaqueous medium for the formation of pure ammonium carbamate. This makes the process completely ecofriendly and cost‐effective. A continuous process of ammonium carbamate production at 20°C results in 88.86% consumption of carbon dioxide. The highest yield of ammonium carbamate was achieved at an NH 3 /CO 2 ratio of 2.5. A three‐stage setup was also found to increase the yield of ammonium carbamate. The reusability of oil after each cycle was checked and it was found that the formation of the product is comparatively less compared to the previous cycle. Lower yield was observed when the same experiment was carried out with fresh oil (sunflower oil). The exit gas from the process was found to be rich in ammonia that can be further used for the production of struvite, a phosphate fertilizer. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.