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The effects of ammonium paratungstate silicon dioxide catalyst load (AMT / SiO2) and methanol vapor performance catechol monoethers reaction. The results showed that the 533 and 573 K calcined AMT / SiO2 catalyst showed higher hydroquinone conversion rate (97%) and the main products of o-hydroxy anisole selectivity (91%) and temperature programmed desorption of pyridine adsorption infrared spectroscopy, results showed that the catalyst is present on the surface of the weak acid - weak base position is the reaction of the active center the Commission catalyst calcinated at 533K reaction was held within the first 46h high stability, a longer reaction time, catechol conversion rate gradually decreased, but the main product selectivity remain substantially unchanged. Scanning electron microscopy and differential hot re-analysis showed that the active catalyst surface carbon deposition is the main reason for the decline, with appropriate roasting process can eliminate most of the coke so as to partially restore catalyst activity.

O-hydroxy anisole is an important fine chemical intermediates and chemical raw materials, it has a wide range of uses catechol - Methanol Synthesis Gas monoetherification o-hydroxy anisole due to economic and environmental advantages and concern, has It found that some of the reaction is more effective catalyst systems, including a variety of composite oxides, phosphates and zeolites.

Our previous studies phosphates and phosphate multicomponent catalyst found that a weak acid - weak base properties of the catalyst is usually the reaction of catechol and methanol vapor phase synthesis of o-hydroxy anisole showed high activity and selectivity sex. recently, we have found that silicon dioxide(SiO2), TiO2, and Al2O3 as the carrier prepared supported metatungstate (AMT) catalyst to the reaction show good catalytic performance. among them, tungsten loading was 7.9% of the AMT / SiO2 catalyst performance best preliminary characterization results indicate that in firing by the preparation process of the decomposition of ammonium metatungstate having a portion forming a weak acid - species weak base properties of the active center of the catalytic reaction of this paper based on this study focused on the roasting Effect of temperature on catechol and methanol vapor single etherification performance AMT / SiO2 catalyst regeneration and investigate the stability and performance of the catalyst. Meanwhile, the combination of X-ray diffraction (XRD), infrared spectroscopy (IR), program temperature-programmed desorption (TPD), scanning electron microscopy (SEM) and differential thermal - thermogravimetric (TG-DTA) were characterized by means of the catalyst structure, surface properties and deactivation of acid were discussed.


 

 

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