Progress of Catalytic Valorization of Bio-Glycerol with Urea into Glycerol Carbonate as a Monomer for Polymeric Materials

Table 3

Catalytic glycerolysis of urea to GC using tungsten-based catalyst.

Entry	Catalyst	Acid amount (mmol/g)	Base amount (mmol/g)	Reaction conditions	Yield of GC (%)	Ref.
1	SW21	0.472	—^a	140℃, 4 h	49.4	[99]
2	5 wt% WO3-SnO2	0.271	—^a	140℃, 4 h	85.4^b	[100]
3	15% WO3/TiO2	0.554	—^a	140℃, 4 h	73	[101]
4	30% SiW12/MCM-41	3.4	—^a	150℃, 8 h	77^b	[102]
5	SiW-Hß	3.5	—^a	150℃, 8 h	75^b	[103]
6	Sm0.66TPA	1.726	—^a	140℃, 4 h	85^b	[111]
7	Sn-CsPW	528	—^a	140℃, 4 h	85^b	[112]
8	Ta0.4TPA	0.128	—^a	140℃, 4 h	100^b	[113]

^aNot reported. ^bGC selectivity.