... Journal of Organic Chemistry. ... 8, trifluoroethylamine, 5.70, 0.0407. a pK a taken from: Jencks, WP; Regenstein, J. In Handbook of Biochemistry, 2nd ed.; Sober, HA, Ed.; Chemical Rubber Publishing Co.: Cleveland, OH, 1970; p J-203. Gilchrist, M.; Jencks, WP J. Am. Chem. ...