Table 1. Hydrogenation of CO₂ to C₂₊OH using different catalytic systems ^a .

Entry	Catalyst precursors	Promoter	Cocatalyst	Solvent	STY b [C mmol L–1 h–1]					C2+OH Sel. [%]
					Methanol	Ethanol	Propanol	Isobutanol	Total
1	Ru3(CO)12, Co4(CO)12	LiBr	PPNCl	DMI	3.1	29.5	0.6	0.5	33.7	90.8
2	Ru3(CO)12, Co4(CO)12	—	PPNCl	DMI	10.2	0.7	0.1	0	11.0	7.3
3	Ru3(CO)12, Co4(CO)12	LiBr	—	DMI	9.5	19.2	0.4	0.3	29.4	67.7
4 c	Ru3(CO)12, Co4(CO)12	—	—	DMI	0.5	0	0	0	0.5	0
5	Ru3(CO)12, Co4(CO)12	LiCl	PPNCl	DMI	35.5	13.1	1.0	0	49.6	28.4
6	Ru3(CO)12, Co4(CO)12	LiI	PPNCl	DMI	0.4	1.9	3.9	0	6.2	93.5
7 c	Ru3(CO)12, Co4(CO)12	LiBF4	PPNCl	DMI	2.7	0.3	0	0	3.0	10.0
8	Ru3(CO)12, Co4(CO)12	NaBr	PPNCl	DMI	42.4	2.5	0	0	44.9	5.6
9	Ru3(CO)12, Co4(CO)12	KBr	PPNCl	DMI	47.5	2.6	0	0	50.1	5.2
10	Ru3(CO)12, Co4(CO)12	KI	PPNCl	DMI	44.4	4.5	0	0	48.9	9.2
11	Ru3(CO)12	LiBr	PPNCl	DMI	12.1	20.8	0	0	32.9	63.2
12	Co4(CO)12	LiBr	PPNCl	DMI	0.3	0	0	0	0.3	0
13	Ru3(CO)12, Co4(CO)12	LiBr	LiCl	DMI	1.3	5.9	0.5	0.2	7.9	83.5
14	Ru3(CO)12, Co4(CO)12	LiBr	TBACl	DMI	8.9	23.4	0.8	0.7	33.8	73.7
15	Ru3(CO)12, Co4(CO)12	LiBr	TPPTS	DMI	10.1	13.3	0.2	0	23.6	57.2
16	Ru3(CO)12, Co4(CO)12	LiBr	PPh3	DMI	10.9	13.7	0.3	0	24.9	56.2
17	Ru3(CO)12, Co4(CO)12	LiBr	Imidazole	DMI	5.1	11.5	0	0	16.6	69.3
18	Ru3(CO)12, Co4(CO)12	LiBr	PPNCl	NMP	8.7	13.6	4.7	4.0	31.0	71.9
19	Ru3(CO)12, Co4(CO)12	LiBr	PPNCl	DMF	8.2	0	0	0	8.2	0
20	Ru3(CO)12, Co4(CO)12	LiBr	PPNCl	[Bmim]NTf2	1.1	0	0	0	1.1	0
21	Ru3(CO)12, Co4(CO)12	LiBr	PPNCl	1-Methylpiperidine	0	0	0	0	0	0
22	Ru3(CO)12, Co4(CO)12	LiBr	PPNCl	THF	71.4	2.3	0	0	73.7	3.1
23	Ru3(CO)12, Co4(CO)12	LiBr	PPNCl	Cyclohexane	1.2	0.1	0	0	1.3	7.7
24 c	Ru3(CO)12, Co4(CO)12	LiBr	PPNCl	H2O	2.1	1.1	0.1	0	3.3	36.4
25	Ru3(CO)12, Co2(CO)8	LiBr	PPNCl	DMI	10.0	22.6	1.1	0	33.7	70.3
26 c	RuBr3, CoBr2	LiBr	PPNCl	DMI	4.2	8.5	0	0	12.7	66.9
27	(PPh3)3RuCl2, (PPh3)3CoCl	LiBr	PPNCl	DMI	3.1	4.2	0	0	7.3	57.5

^aReaction conditions: 40 μmol Ru catalyst and 20 μmol Co catalyst (based on the metal), 4 mmol promoter, 0.15 mmol cocatalyst, 2 mL solvent, 3 MPa CO₂ and 6 MPa H₂ (at room temperature), 200 °C, 12 h.

^bSTY stands for space time yield (C mmol L^–1 h^–1). The STY was determined by GC analysis using toluene as the internal standard.

^cBlack precipitate was observed after the reaction. Sel.: selectivity.