pK_a values of PhCH(CN)₂ in four IL/DMSO binary mixtures at various molar fractions of ILs χ_IL at 298 K^a.

χ IL b (%)	pKa of PhCH(CN)2a
	[Bmim][NTf2]	[Bmim][OTf]	[Bmpy][NTf2]	[DBUH][OTf]
100	12.5	9.8	12.6	9.8
95	8.0	—	—	—
90	7.3	—	—	—
80	6.7	—	6.55c	6.25c
70	6.4	—	—	—
60	6.1	—	5.75c	5.35c
50	5.7	—	—	—
40	5.3	—	—	—
30	4.9	—	4.75c	4.4
20	4.5	—	—	—
10	4.0	3.9	4.0	3.75c
5	3.8	3.7	3.8	3.6
3	3.75c	3.7	3.75c	3.5
2	3.7	3.65c	3.7	3.4
1	3.65c	3.75	3.75c	3.6
0.75	3.8	—	—	—
0.5	3.9	3.8	3.8	3.75c
0	4.2	4.2	4.2	4.2

^aIn pK_a units; standard deviations ≤ ±0.05. The pK_a in neat DMSO (4.2)⁵² and in the four neat ILs²¹ is cited from the literature.

^b χ _IL, the molar fraction of the IL.

^cThe second decimal number for pK_a.