The invention discloses a technological method for purifying 1,4-
butanediol and co-producing
tetrahydrofuran. The technological method comprises the following steps: a raw 1,4-
butanediol material flow containing 2-(4-hydroxyl butoxy)
tetrahydrofuran enters a 1,4-
butanediol refining
tower, and a 1,4-butanediol product is produced at the side line of the refining
tower; and material flows rich in the 1,4-butanediol at the top and bottom of the refining
tower enter a
tetrahydrofuran reactor,
dehydration cyclization is continuously carried out for producing the tetrahydrofuran through a
palladium carried sulfonating
ion exchange resin catalyst in the presence of
hydrogen; after reaction, a raw tetrahydrofuran
material flow enters a gas-liquid separator, a
gas phase flow is reused or is discharged, and a
liquid phase enters an
azeotropic distillation tower; and
azeotrope of tetrahydrofuran and water is obtained at the tower top and is separated to obtain the tetrahydrofuran product, liquid at the tower bottom enters a
dehydration tower, and a
material flow at the tower bottom returns to the tetrahydrofuran reactor. According to the technological method, the tetrahydrofuran with the
high selectivity is produced while the 1,4-butanediol product with the high purity is separated out, the seperation problem of the 2-(4'-hydroxyl butoxy) tetrahydrofuran in the 1,4-butanediol product flow is solved, and the production cost is greatly reduced; and the technological method is suitable for industrial application.