Sulfation of metal-organic frameworks: Opportunities for acid catalysis and proton conductivity

Maarten G. Goesten, Jana Juan-Alcañiz, Enrique V. Ramos-Fernandez, K. B. Sai Sankar Gupta, Eli Stavitski, Herman Van Bekkum, Jorge Gascon Sabate*, Freek Kapteijn

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

227 Scopus citations

Abstract

A new post-functionalization method for metal-organic frameworks (MOFs) has been developed to introduce acidity for catalysis. Upon treatment with a mixture of triflic anhydride and sulfuric acid, chemically stable MOF structures MIL-101(Cr) and MIL-53(Al) can be sulfated, resulting in a Brønsted sulfoxy acid group attached to up to 50% of the aromatic terephthalate linkers of the structure. The sulfated samples have been extensively characterized by solid-state NMR, XANES, and FTIR spectroscopy. The functionalized acidic frameworks show catalytic activity similar to that of acidic polymers like Nafion® display in the esterification of n-butanol with acetic acid (TOF ∼ 1 min -1 @ 343 K). Water adsorbs strongly up to 4 molecules per sulfoxy acid group, and an additional 2 molecules are taken up at lower temperatures in the 1-D pore channels of S-MIL-53(Al). The high water content and Brønsted acidity provide the structure S-MIL-53(Al) a high proton conductivity up to moderate temperatures.

Original languageEnglish (US)
Pages (from-to)177-187
Number of pages11
JournalJournal of Catalysis
Volume281
Issue number1
DOIs
StatePublished - Jul 1 2011

Keywords

  • Esterification
  • Flexibility
  • MIL-101
  • MIL-53
  • Metal-organic frameworks
  • Proton conductivity

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry

Fingerprint Dive into the research topics of 'Sulfation of metal-organic frameworks: Opportunities for acid catalysis and proton conductivity'. Together they form a unique fingerprint.

Cite this