The invention discloses a method for preparing 9, 9-bis (3, 4-dicarboxyphenyl)
fluorene dianhydride, which specifically comprises the following steps: S1, adding 9-
fluorenone and o-
xylene into a reaction kettle; S2, adding
sulfuric acid and stirring; s3, cleaning is conducted; s4, preparing an intermediate 1; s5, stirring the raw materials until the raw materials are dissolved and clarified, cooling to
room temperature without
solid precipitation, and transferring to a
continuous flow section; s6, carrying out
continuous flow reaction treatment; and S7, adding
acetic anhydride, filtering, and
drying to obtain the 9, 9-bis (3, 4-dicarboxyphenyl)
fluorene dianhydride. The invention relates to the technical field of catalyst preparation. According to the method for preparing 9, 9-bis (3, 4-dicarboxyphenyl)
fluorene dianhydride, a
continuous flow SK mixer is adopted to more fully realize gas-liquid mixing, so that the
reaction rate is increased, the area of a continuous flow reaction unit is small, the risk in the industrialization process is reduced,
continuous production is realized, and the problems of high
safety risk, low productivity and the like of an intermittent reaction kettle are solved.