(500d) High-Yield Conversion of Crude Glycerol to Acrolein In Subcritical Water

Acrolein, which is commercially produced via partial oxidation of petroleum-based propylene, is an important chemical intermediate for many industrial chemicals, leading to an array of high-value end-products. With the continuous shrinkage of petroleum resources and increasing abundance of glycerol due to the expansion of biodiesel industry worldwide, producing acrolein from glycerol, especially crude glycerol, is of high industrial value. A continuous acid-catalyzed process utilizing subcritical water as reaction medium was developed to convert crude glycerol into acrolein. This study focused on investigating the effects of temperature, pressure, acid concentration, and reaction time on the glycerol conversion and acrolein selectivity, and discovering the intrinsic reaction mechanisms to better control the process for high acrolein yield. Lower reaction temperature is preferred from a safety and economic point of view due to the less energy consumption, lower pressure operation, and less stringent requirement on the reactor materials. Therefore, operation parameters were optimized for the lowest possible temperature to achieve maximum acrolein yield. Acrolein yield from crude glycerol over 80 mol% has been achieved in this study.