AMT/SiO2 Catalyst on Orthortho-Hydroxy Anisole Production I

Orthortho-hydroxy anisole is important fine chemical intermediates and chemical raw materials, with a wide range of applications. Pyrocatechol - Methanol Gas phase single etherification method to produce orthortho-hydroxy anisole has attracted much attention due to its advantages of economic and environmental, some effective catalyst systems of this reaction have been found including a variety of complex oxides, phosphates and zeolite.

According to preliminary studies on phosphates and phosphate multicomponent catalyst, it’s found that a weak acid - weak alkali catalyst usually shows high activity and selectivity on the reaction of pyrocatechol and methanol vapor phase synthesis of orthortho-hydroxy anisole. Recently, scholars have found that supported ammonium metatungstate (AMT) catalyst prepared by SiO2, TiO2, and Al2O3 as the carrier has good catalytic performance on this reaction. In which the tungsten loading of 7.9% of AMT / SiO2 catalyst has the best performance. Preliminary characterization results show that the weak acid - weak alkali species formed by ammonium metatungstate partial decomposition are the the active center of the catalytic reaction in roasting preparation processing. On this basis, the study focused on the influence of calcination temperature on pyrocatechol and methanol vapor single etherification performance with AMT / SiO2 catalyst and examine the stability and performance of the catalyst regeneration. Meanwhile, according to X-ray diffraction (XDR), infrared spectroscopy (IR), temperature programmed desorption (TPD), scanning electron microscopy (SEM) and differential thermal - thermogravimetric (TG-DTA), catalyst structure, surface acidity the nature and reasons for deactivation were discussed.