Method for producing resorcinol by using sulfur trioxide

The invention discloses a method for producing resorcinol by using sulfur trioxide. The method comprises the following steps: (1) carrying out primary sulfonation on benzene and sulfur trioxide in a tubular reactor with a jacket, and controlling the reaction temperature to be 30-40 DEG C through circulating water introduced into the jacket; (2) transferring the primary sulfonation material into asecondary sulfonation reaction kettle, and introducing sulfur trioxide for secondary sulfonation; (3) carrying out a neutralization reaction on the secondary sulfonation product and sodium sulfite, wherein sulfur dioxide generated in the neutralization process is used as an acidification reagent; (4) melting sodium hydroxide, and then adding the neutralized sulfonation liquid into the molten sodium hydroxide for an alkali fusion reaction; (5) adding water into the alkali fusion reaction solution to dilute the solution; and (6) introducing sulfur dioxide generated in the neutralization reactionstep into water for acidi