▎ 摘　　要

NOVELTY - Preparing styrene comprises (i) alkali lignin pyrolysis: adding alkali lignin, ferric chloride heme/graphene hybrid material and hydrogen peroxide into a reactor, adding sodium hydroxide solution to adjust pH of the reaction solution, and reacting under stirring condition until the reaction mixture becomes homogeneous and black, and (ii) separating and purifying the target product: centrifuging, adjusting pH of the supernatant, precipitating, centrifuging and filtering, extracting the supernatant, rotary evaporating to obtain liquid product, dissolving in analytically pure acetone, and drying. USE - The method is useful for preparing styrene (claimed). ADVANTAGE - The method: utilizes renewable resources having stable and low cost; is simple; requires less equipment; has low production cost; utilizes HGN catalyst, which can be recycled; requires mild reaction temperature; consumes low energy; and can reduce the production cost. DETAILED DESCRIPTION - Preparing styrene comprises (i) alkali lignin pyrolysis: adding alkali lignin, ferric chloride heme/graphene hybrid material and hydrogen peroxide into a reactor, then adding sodium hydroxide solution to adjust pH value of the reaction solution, and reacting in a constant temperature oil-bath under stirring condition until the reaction mixture becomes homogeneous and black, and (ii) separating and purifying the target product: centrifuging, adjusting the pH of the supernatant by using concentrated hydrochloric acid, allowing to stand for precipitating, then centrifuging and filtering the mixture, extracting the supernatant, rotary evaporating under vacuum condition in an oil bath to obtain liquid product, dissolving in analytically pure acetone, and drying over anhydrous magnesium sulfate to obtain styrene.