Table 1. Hydrogenation of carbon dioxide to methanol in the absence of alcohol additive ^a .

Entry	Cat	Acid (eq.)	T [°C]	p CO2/pH2 b [bar/bar]	TON c
1	2	HNTf2 (1.0)	140	20/60	228
2	2	—	140	20/60	8
3	4	—	140	20/60	165
4	4	HNTf2 (0.5)	140	20/60	156
5	2	HNTf2 (1.5)	140	20/60	196
6	2	HNTf2 (2.0)	140	20/60	181
7	2	p-TsOH (1.0)	140	20/60	135
8	2	HNTf2 (1.0)	120	20/60	169
9	2	HNTf2 (1.0)	100	20/60	67
10	2	HNTf2 (1.0)	80	20/60	24
11	2	HNTf2 (1.0)	140	10/30	78
12	2	HNTf2 (1.0)	140	30/90	367
13	2	HNTf2 (1.0)	140	20/80	301
14	2	HNTf2 (1.0)	140	20/100	348
15 d	2	HNTf2 (1.0)	140	20/60	335
16 e	2	HNTf2 (1.0)	140	20/60	442
17 d	12	HNTf2 (1.0)	140	20/60	256

^aReaction conditions: 25 μmol [Ru], 2.08 mL THF, 24 h.

^bAt room temperature.

^cTON = mmol MeOH per mmol catalyst.

^d12.5 μmol [Ru].

^e6.3 μmol [Ru].