Table 3. Effect of Varying the Acid Component of a 2:1 Acid:TMG Homoconjugate Catalyst in Silanol Polycondensation.

entry	catalyst	mol % cat.	Mn (Da)	Mw (Da)	Đ	conversion (%)	D4 (ppm)	acid pKa32a
1	[TMG][AcOH]2	1.3	18,900	37,500	2.0	86	149	4.76
2	[TMG][TFA]2	0.13	83,600	164,500	2.0	97	144	–0.25
3	[TMG][TsOH]2	0.13	40,200	74,000	1.8	93	252	–2.6b
4	[TMG][PFBSA]2	0.0013	9800	16,400	1.7	73	217	–14c
5	[TMG][AcOH][TFA]	1.3	3400	6700	2.0	22	41d

^apK_a values in water.

^bpK_a value for MeSO₃H.

^cpK_a value for CF₃SO₃H.

^dIt is possible that some D4 was lost during the reaction or analysis, leading to a value lower than that of DOWSIL Q1-3563 (50 ppm).