▎ 摘　　要

NOVELTY - Producing graphene, comprises (a) preprocessing by (a1) mixing polar aprotic solvent and graphite, separating and recovering graphite, (a2) mixing the recovered graphite with first polar aprotic solvent, then separating and recovering graphite, and (a2-1) mixing the recovered graphite with the second polar aprotic solvent, then separating and recovering graphite, and (b) preparing oxidized graphene dispersion by chemical oxidation exfoliation of the pretreated graphite. USE - The method is useful for producing graphene (claimed). ADVANTAGE - The method improves purity and yield, can produce single layer graphene, and is economical and is simple. The graphene has excellent electrical conductivity under low temperature. DETAILED DESCRIPTION - Producing graphene, comprises either: (a) preprocessing by (a1) mixing polar aprotic solvent and graphite, separating and recovering graphite, (a2) mixing the recovered graphite with first polar aprotic solvent, then separating and recovering graphite, (a2-1) mixing the recovered graphite with the second polar aprotic solvent, then separating and recovering graphite, and (b) preparing oxidized graphene dispersion by chemical oxidation exfoliation of the pretreated graphite; or (i) producing graphene oxide and (ii) reducing the graphene oxide to produce reduced graphene oxide. The polar aprotic solvent includes acetonitrile, ethyl acetate, methyl acetate, butyl acetate, ethylene glycol dimethyl ether, isobutyl acetate, propyl acetate, dimethoxymethane, methyl ethyl ketone and/or acetone. The first polar aprotic solvent includes methanol, isobutanol, ethanol, 1-propanol, 2-propanol and/or 1-butanol. The second polar aprotic solvent is water.