Table 2. Influence of experimental conditions on propylene carbonate yields.* .

Entry	Catalyst (mg)	TBAB (mmol)	CO2 pressure† (MPa)	Temperature (°C)	Time (h)	Yield‡ (%)	TON§
1||	Salen-Co-OAc 81.0	1.8	0.1	25	48	77.1	158
2	Co-CMP 100	0	0.1	25	48	6.7	14
3	Co-CMP 0	1.8	0.1	25	48	20.4	3¶
4	Co-CMP 100	1.8	0.1	25	48	81.5	167
5	Al-CMP 95.2	1.8	0.1	25	48	78.2	160
6	KI 20.3	0	0.1	25	48	3.8	8#
7	KI/β-CD 20.3+138	0	0.1	25	48	3.9	8#
8||	Salen-Co-OAc 81.0	1.8	3.0	100	1	84.6	173
9	Co-CMP 0	1.8	3.0	100	1	31.0	4¶
10	Co-CMP 100	1.8	3.0	100	1	98.1	201
11	Al-CMP 95.2	1.8	3.0	100	1	91.2	187
12**	Co-CMP 100(O2)	1.8	3.0	100	1	96.0	197
13††	Co-CMP 100(H2O)	1.8	3.0	100	1	94.1	193
14††	Al-CMP 95.2(H2O)	1.8	3.0	100	1	72.9	149
15	KI 20.3	0	3.0	100	1	3.0	6#
16‡‡	KI/β-CD 20.3+138	0	3.0	100	1	13.2	27#

All reactions were conducted in the absence of additional solvent unless otherwise noted.

^*Reaction conditions: propylene oxide (25 mmol), Co-CMP (100 mg, Co: 0.122 mmol) or Al-CMP (95.2 mg, Al: 0.122 mmol) or Salen-Co-OAc (81.0 mg, Co: 0.122 mmol) or KI (20.3 mg, 0.122 mmol), unless otherwise noted.

^†Initial pressure.

^‡Yield of the isolated product obtained after column chromatography.

^§TON=(moles of product)/(moles of metal in the catalyst), unless otherwise noted.

^||Co-CMP was replaced with Salen-Co-OAc in the catalytic reaction. Salen-Co-OAc=[(R, R)-N′N′-bis(5-bromo-3-tert-butyl-salicylidene)-1,2-cyclohexanediaminate] cobalt (III) acetate.

^¶TON=(moles of product)/(moles of TBAB in the catalyst).

^#TON=(moles of product)/(moles of KI in the catalyst).

^**Not excluding the air inside the reaction system.

^††0.2 ml of H₂O was added to the reaction system.

^‡‡β-CD (β-cyclodextrin) (0.122 mmol, 138 mg) was added.