Table 1.

Cycloaddition of CO₂ and ECH catalyzed by various catalysts

Entry	Catalyst	Solubility	Yielda (%)	Selb (%)
1	No catalyst	Homogeneous	–	–
2	DVB-HTA	Heterogeneous	90	98
3	DVB-BTA	Heterogeneous	84	92
4	HTA	Homogeneous	84	97
5	BTA	Homogeneous	77	95

Reaction conditions: ECH (16 mmol), CO₂ (1.2 MPa), catalyst (0.035 mmol based on Br), 120 °C, 3 h

^aThe yield of cyclic carbonate product

^bThe selectivity for the cyclic carbonate product; the byproduct is 3-chloro-1,2-propanediol