TABLE 2.

Kinetic constants for each step of the reductive half-reaction in the absence and presence of various salts and a viscogen at 4 °C

	No addition	+300 mm Na2SO4	+100 mm NaCl	+300 mm NaBr	+30% (w/v) glycerol
k+1 (s−1)a	887 ± 0.2	880 ± 0.3	887 ± 0.6	880 ± 0.08	871 ± 0.03
k−1 (s−1)	531 ± 0.8	529 ± 0.05	530 ± 0.2	528 ± 2	560 ± 0.02
k+2 (s−1)	206 ± 0.04	207 ± 0.1	206 ± 0.1	207 ± 0.3	201 ± 0.006
k−2 (s−1)	34 ± 0.008	34 ± 0.02	34 ± 0.02	34 ± 0.07	34 ± 0.001
k+3 (s−1)	102 ± 0.06	102 ± 0.05	102 ± 0.06	103 ± 0.2	100 ± 0.003
k−3 (s−1)	127 ± 8	127 ± 5	63 ± 3	76 ± 7	134 ± 0.007
k+4 (s−1)	39 ± 9	39 ± 6	32 ± 6	23 ± 11	15 ± 0.001
k−4 (s−1)	17 ± 3	12 ± 2	15 ± 4	21 ± 6	6 ± 0.001
k+5 (s−1)a			15 ± 7	21 ± 12
k−5 (s−1)			5 ± 2	9 ± 3

^a Determined as a first-order rate constant at constant and excess concentrations of amine substrate (2-PEA) and halide ions.