Synthesis and Characterization of 5-Hydroxymethylfurfural from Corncob Using Solid Sulfonated Carbon Catalyst

Table 5

Total acid density and amount of -SO₃H, COOH, and OH groups of catalyst.

Sample type	Total acid density (mmol/g)	The amount of -SO3H group (mmol/g)	COOH and OH (mmol/g)
BC-SO3H−1	3.5	0.61	2.89
BC-SO3H−2	3.43	0.45	2.98
BC-SO3H−3	3.28	0.24	3.04

Note: BC-0 is carbon catalyst without sulfonation; BC-SO₃H₋₁, BC-SO₃H₋₂, and BC-SO₃H₋₃ are carbon catalysts sulfonated with different concentrations of H₂SO₄ (98%, 96%, and 94%), respectively.