Synthesis of Sulfonic Acid Functionalized Silica Honeycombs

• Published in: Industrial & engineering chemistry research Vol. 52; no. 44; pp. 15293 - 15297
• Main Authors: Satoh, Yoshitaka, Yokoyama, Yuya, Ogino, Isao, Mukai, Shin R
• Format: Journal Article
• Language: English
• Published: American Chemical Society 06.11.2013
• Subjects: Catalysts; Catalytic activity; Ethyl alcohol; Honeycomb; Reactors; Silicon dioxide; Sulfonic acid; Walls
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie400541d

A honeycomb-type silica monolith was functionalized with sulfonic acid groups to synthesize a solid acid catalyst for flow reaction systems. The sulfonic acid groups were introduced via anchoring of 3-mercaptopropyltrimethoxysilane (MPTS) on the silica surface and subsequent oxidation using a H2O2 solution. The honeycomb-type monolith used as the substrate was prepared using ice crystals as a template and was found to have a high open frontal area of ≈85% and flow-through macropores (≈27 μm in diameter) that are surrounded by silica walls (≈2 μm in thickness). The catalyst was tested by the liquid phase esterification of ethanol with acetic acid at 333 K in a batch reactor as well as a flow reactor. The catalyst was found to exhibit about 2-fold higher catalytic activity than Amberlyst-15 in a batch reactor. The catalyst also showed a stable catalytic activity for 24 h in a flow reactor.