Dehydrogenation of pyrrolidine based liquid organic hydrogen carriers by an iridium pincer catalyst, an isothermal kinetic study. (14th December 2015)

• Record Type: Journal Article
• Authors: Brayton, Daniel F.; Jensen, Craig M.
• Is Part Of: International journal of hydrogen energy. Volume 40:Number 46(2015)
• Page Start: 16266
• Page End: 16270
• Publication Date: 2015-12-14
• Subjects: Hydrogen -- Liquid organic carrier -- Hydrogen storage -- Iridium -- Activation energy -- Frequency factor; LOHC liquid organic hydrogen carrier -- DOT dehydrogenation onset temperature -- EPHC ethyl perhydrocarbazole -- EC ethylcarbazole -- MePHI methylperhydroindole -- PHIz perhydroindolizine; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2015.10.014
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: A previously known homogenous iridium POCOP tBu pincer catalyst and several pyrrolidine based liquid organic hydrogen carriers (LOHCs) were investigated under dehydrogenation conditions and analyzed in a pseudo first order kinetic fashion to determine various kinetic properties. Dehydrogenation onset temperatures (DOT) of 180, 160, and 140 °C; activation energies (EA ) of 115, 142, and 166 (kJ/mol); and frequency factor (A) values of 3.56 × 10 8, 1.05 × 10 11, and 2.17 × 10 14 (s −1 ) were found for ethyl perhydro carbazole (EPHC, 2 ), methyl perhydro indole (MePHI, 3 ), and butyl pyrrolidine (BuPy, 4 ) respectively. The dehydrogenation onset temperatures correlate with collision frequency factors rather than the activation energies. This evidence suggests that it is a steric constraint approach of the LOHC rather than a barrier to C–H bond activation at the iridium center which limits the rate of reaction.