The invention discloses a carbon-based
solid acid catalyst and a preparation method thereof. The preparation method comprises the following steps: proportionally mixing carbon-containing raw materials and a
chlorine-containing organic high-molecular compound, and carbonizing a mixture to obtain a black
solid product; cooling and
grinding the black
solid product, and adding a sulfonating agent to perform sulfonating; performing cooling, filtering, washing and
drying to obtain a black
granular material, wherein the sulfonic group density of the black
granular material is 0.1 to 5mmol / g, the
chlorine content of the black
granular material is 0.2 to 70mg / g, and the
molar ratio of C to H to O is 1:(0.05-1.3):(0.1-1). The black granular material comprises a carbon framework and active sites, wherein aromatic
carbon layer sheets which are in bridge bond connection so as to form a basic unit; the active sites are connected to the
carbon layer sheets and comprise -Cl, -SO3H, -OH and -COOH. The carbon-based
solid acid catalyst prepared by using the method is stable in structure, high in acidity, low in cost, good in
catalytic effect, easy to recycle and wide in application prospect.