▎ 摘　　要

NOVELTY - Preparing magnetic complex cellulose-based solid acid catalyst comprises e.g. (i) (a) placing cellulose into the ionic liquid 1-butyl-3-methylimidazolium chlorate, mechanically stirring to obtain a cellulose solution, (b) preparing graphite oxide by Hummers method, and graphene oxide was obtained by ultrasonication, adding anhydrous p-aminobenzenesulfonic acid to sodium hydroxide solution in a hot water bath, dissolving, cooling to room temperature, adding sodium nitrite, dissolving, and mixing the mixture solution into a beaker containing ice water and concentrated hydrochloric acid under stirring, when p-aminobenzene sulfonate the white precipitation of the acid diazonium salt, stirring the reaction, adding to the suspension of graphene oxide under ice bath conditions, stirring, washing with deionized water to neutral, (c) synthesizing ferrous oxide nanoparticles by chemical precipitation method using ferrous chloride hexahydrateand as raw materials. USE - The method is useful for preparing magnetic complex cellulose-based solid acid catalyst. ADVANTAGE - The catalyst: has high catalytic activity, mild reaction condition, strong magnetic property and long-lasting property, and is economical. DETAILED DESCRIPTION - Preparing magnetic complex cellulose-based solid acid catalyst comprises (i) (a) placing cellulose into the ionic liquid 1-butyl-3-methylimidazolium chlorate, mechanically stirring at 85-95 degrees C for 10 hours to obtain a cellulose solution, (b) preparing graphite oxide by Hummers method, and graphene oxide was obtained by ultrasonication, adding anhydrous p-aminobenzenesulfonic acid to a 2% sodium hydroxide solution in a hot water bath, dissolving, cooling to room temperature, adding sodium nitrite, dissolving, and mixing the mixture solution into a beaker containing ice water and concentrated hydrochloric acid under stirring to control the temperature at 0 degrees C, when p-aminobenzene sulfonate the white precipitation of the acid diazonium salt, stirring the reaction for 15 minutes to obtain diazonium salt of p-aminobenzenesulfonic acid, adding the diazonium salt of p-aminobenzenesulfonic acid dropwise to the suspension of graphene oxide under ice bath conditions, stirring for 2-4 hours, washing with deionized water to neutral, and finally obtaining sulfonated graphene oxide, drying in a vacuum oven at 60 degrees C, (c) synthesizing ferrous oxide nanoparticles by chemical precipitation method using ferrous chloride hexahydrateand as raw materials, calculating ratio of ferric ion to ferrous ion was 2:1, mixing the iron salt and the ferrous salt and dissolving in water, and slowly adding the ammonia aqueous solution to a pH value of 9-10 under high-speed stirring, and washing with water until neutral to obtain magnetic ferroferric oxide nanoparticles, and drying, (d) ultrasonically dispersing prepared mixture of ferroferric oxide nanoparticles and sulfonated graphene oxide, and mixing with calcium carbonate in a cellulose solution, and adding the mixture from 300ml to 400ml transformer oil dispersed in 30ml of potassium oleate and Siban 60 from room temperature to 80-90 degrees C, mechanically stirring with a high-speed mixer for 2.5-3.5 hours to form a complex sphere, and repeatedly washing complex microspheres with absolute ethanol and hydrochloric lacid until the pores of hydrochloric acid are completely formed, the pH of the waste liquid is acidic, and separaring by a magnet, and the obtained complex mesoporous microspheres are magnetic complex cellulose-based solid acid catalysts, vacuum drying the catalyst to constant weight, (ii) adding specific amount of oil, methanol and magnetic complex cellulose-based solid acid catalyst to the reaction flask, and refluxing for a period of time after stirring, separating the catalyst from the reaction mixture by an external magnetic field, ethanol washing and drying to recover, transferring the reaction solution to a separatory funnel, and extracting with n-hexane and water, allowing to stand the mixture for separation, recovering the upper phase biodiesel (fatty acid methyl ester) and n-hexane by vacuum distillation to obtain biodiesel and GCMS was used for yield analysis.