蒽醌法生产H₂O₂

The anthraquinone process, also known as the Riedl-Pfleiderer process, is an elegant example of a catalytic cycle. The process begins with a solution of a 2-alkylanthraquinone (e.g., 2-ethylanthraquinone) in a mixture of organic solvents. This solution is hydrogenated using a 催化剂, typically palladium on a solid support. The hydrogenation reduces the quinone groups to hydroquinone groups, forming 2-alkylanthrahydroquinone. This is the reduction step. Following this, the solution is moved to an oxidizer vessel where it is bubbled with compressed air. The oxygen in the air oxidizes the anthrahydroquinone back to the original 2-alkylanthraquinone, and in the process, produces hydrogen peroxide. The overall reaction is [latex]H_2 + O_2 \rightarrow H_2O_2[/latex]. The hydrogen peroxide formed is immiscible with the organic solvent mixture and is extracted using demineralized water. The resulting aqueous solution is typically around 40% H₂O₂ by weight. This solution can then be purified and concentrated by vacuum distillation to produce various commercial grades, up to 70% or even higher for specialized applications. The organic solution containing the regenerated anthraquinone is dried and recycled back to the hydrogenation step, making the process a continuous loop. The only net inputs are hydrogen and oxygen (from air), and the only output is hydrogen peroxide (and water).

烷基和溶剂系统的选择对工艺的效率至关重要，因为它会影响溶解度、反应速率和中间产物的稳定性。可能会发生一些副反应，导致蒽醌降解，这就需要定期补充和净化工作溶液。尽管如此，该工艺仍具有高效性和可扩展性，因此 80 多年来一直是批量生产 H₂O₂ 的标准方法。.