Continuous H 2 O 2 direct synthesis process: an analysis of the process conditions that make the difference

Green Processing and Synthesis

article

Irene Huerta¹  Pierdomenico Biasi²  Juan García-Serna¹  María J. Cocero¹  Jyri-Pekka Mikkola²  Tapio Salmi² 

[1] High Pressure Processes Group (hpp.uva.es), Department of Chemical Engineering and Environmental Tech., University of Valladolid;Industrial Chemistry and Reaction Engineering, Process Chemistry Center (PCC) Department of Chemical Engineering, Åbo Akademi University;Department of Chemistry, Chemical-Biochemical Centre (KBC), Umeå University

关键词: direct synthesis;    heterogeneous catalysis;    hydrogen peroxide;    palladium on carbon;    trickle bed reactor;   

DOI  :  10.1515/gps-2016-0001

来源: De Gruyter

【 摘 要 】

A trickle bed reactor (TBR) was used to study different process parameters upon hydrogen peroxide direct synthesis. The catalysts used were commercial palladium on active carbon. The influence of pressure (1.75–25 barg), temperature (5–60°C), liquid flow rate (2–13.8 ml·min -1 ), gas flow rate (3.4–58.5 ml·min -1 ), catalyst amount (90–540 mg), Pd percentage on the support (5% wt., 10% wt. and 30% wt. Pd/C) as well as promoter concentrations (0.0005–0.001 m ) were all varied as process parameters to better understand the behaviour of the system. By contrast, the gas phase molar composition of the feed (4:20:76=H 2 :O 2 :CO 2 ) was kept constant. The strong influence between liquid flow rate, gas flow rate and catalyst amount were identified as the key parameters to tune the reaction, and related to the activity of the catalyst. In essence, these parameters must be carefully tuned to control the hydrogen consumption. The maximum productivity (289 μmol H 2 O 2 ·min -1 ) and yield (83.8%) were obtained when a diluted bed of 30% Pd/C was applied. The H 2 O 2 hydrogenation was studied in order to understand its role in the H 2 O 2 direct synthesis reaction network. The hydrogenation reaction mechanism and the role of NaBr were identified thanks to the experiment proposed in the present work. Consequently, understanding the whole reaction mechanism from the process conditions studied led to a deeper understanding of all of the phenomena involved in the H 2 O 2 direct synthesis.

【 授权许可】

CC BY