HZSM-5 CATALYZED CYCLODEHYDRATION OF DIETHYLENE GLYCOL AND ITS DERIVATIVES

Diethylene glycol (DEG) is converted into 1,4-dioxane using HZSM-5 as a catalyst at 205-225 degrees C in the liquid phase. Triethylene glyco l, diethylene glycol ethers and PEG gave relatively lower yields of 1, 4-dioxane. NH3 adsorption followed by TPD suggests that acidic sites w ith NH3 desorbing above 350 degrees C are responsible for the cyclodeh ydration of DEG and its derivatives. Correlation of activity and effic iency of the catalyst with density of strongly acidic sites suggests t hat both cyclodehydration and deactivation of the catalysts take place simultaneously.