Method for producing tetrahydrofuran

(I) A method for producing tetrahydrofuran, comprising feeding 1,4-butanediol to a reactor and performing a cyclodehydration reaction in the presence of an acid catalyst to obtain tetrahydrofuran, wherein a water concentration in a in-reactor liquid phase is within a range of 1.4 to 10 wt %;

• (II) a method for producing tetrahydrofuran, comprising feeding 1,4-butanediol containing 2-(4-hydroxybutoxy)-tetrahydrofuran to a reactor and performing a cyclodehydration reaction in the presence of an acid catalyst to obtain tetrahydrofuran, wherein a θ value of the following formula (1) is within a range of 0.001 to 0.5:
• θ=B/(W·T) (1)
• (in formula (1), T represents a reaction time (hr), B represents a cumulative weight (g) of 2-(4-hydroxybutoxy)-tetrahydrofuran in the reaction time T, and W represents an in-reactor liquid-phase water weight (g) in the reaction time T);
• or
• (III) a method for producing tetrahydrofuran, comprising feeding 1,4-butanediol to a reactor and performing a cyclodehydration reaction in the presence of an acid catalyst to obtain tetrahydrofuran, wherein the cyclodehydration reaction is performed by a reaction distillation method and a 2-hydroxytetrahydrofuran concentration in the in-reactor liquid phase is within a range of 500 ppm by weight or less.