69.6
[]. Shashi Kant Shukla, et al. Probing the acidity of carboxylic acids in protic ionic liquids, water, and their binary mixtures: activation energy of proton transfer. J Phys Chem B. 20 Feb 28;7(8):2456-65.
H5-H9-H5
P26-P264-P27-P280-P02+P52-P04+P40-P62+P64-P405-P50