Effects of boron and fluorine modified γ-Al2O3 with tailored surface acidity on catalytic ethanol dehydration to ethylene
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The effect of boron and fluorine modified γ-Al2O3 was investigated during ethanol dehydration to ethylene. The conventional and modified γ-Al2O3 were prepared by a sol–gel method and characterized by various techniques. The results showed that boron modified γ-Al2O3 possessed decreased amount of Lewis acid sites by increasing the boron content. Fluorine modified γ-Al2O3 created new Brönsted acid sites with increasing the fluorine content, which resulted in the coexistence of Brönsted and Lewis acid sites, at the same time, strong acid sites appeared. Boron modified γ-Al2O3 catalyst (Al-B1) at 340 °C exhibited excellent catalytic stability and good selectivity for ethanol conversion to ethylene. The improvement in the catalytic stability could be attributed to the lower acidity after boron modification. The results indicated that on γ-Al2O3 catalyst, strong acid sites especially Brönsted acid sites were responsible for coking deactivation and unfavorable to ethanol dehydration to ethylene.
Keywordsγ-Al2O3 Ethanol dehydration Acid sites Ethylene Boron modification
This work was supported by the National Science Foundation of Jiangsu Province (No. BK20140182), National Natural Science Foundation of China (Nos. 21606252 and 21506247), and the Priority Academic Program Development of Jiangsu Higher Education Institutions.
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