Selective production of 1,3-butadiene in the dehydration of 1,4-butanediol over rare earth oxides

Vapor-phase dehydration of 1,4-butanediol and 3-buten-1-ol to produce 1,3-butadiene was investigated over rare earth oxides such as Lu2O3, Yb2O3, Tm2O3, Er2O3, and Sc1.0Yb1.0O3. In the dehydration of 3-buten-1-ol, heavy rare earth oxides such as Lu2O3, Yb2O3, and Er2O3 showed high catalytic performance for the selective formation of 1,3-butadiene with producing small amount of propylene whereas acidic catalysts such as alumina decomposed 3-buten-1-ol into propylene. In particular, over Yb2O3 calcined at 800 degrees C, 3-buten-1-ol was converted with a yield of 1,3-butadiene higher than 95% at 340 degrees C. In the dehydration of 1,4-butanediol, furthermore, we developed an efficient catalytic system: 1,3-butadiene was produced via an intermediate, 3-buten-1-ol, over Yb2O3 with an excellent yield of 96% at 360 degrees C and a high contact time of 2.26 h. Yb2O3 successfully inhibited the major side reaction such as decomposition of 3-buten-1-ol to propylene and provided the selective production of 1,3-butadiene from 1,4-butanediol.