کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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59377 | 1419419 | 2016 | 7 صفحه PDF | دانلود رایگان |
The synthesis of anisole by vapor phase methylation of phenol with methanol over activated alumina (AA) supported catalysts was investigated in a fixed bed reactor. KH2PO4/AA gave the best performance among the eight tested catalysts. The catalyst was prepared by loading KH2PO4 on AA and then calcining at the optimized temperature of 700 °C for 8 h. In the vapor phase reaction, the level of anisole yield (LAY) has a maximum at 400–450 °C when the temperature varied from 300 to 500 °C, which decreased slightly with increasing WHSV and increased distinctly with increasing mole fraction of methanol. On comparing O-methylation and C-methylation of phenol, a low temperature, high WHSV (short residence time), and a low methanol concentration over the KH2PO4/AA catalyst with higher K contents were found to increase anisole selectivity by O-methylation of phenol. The reaction routes to the major products and the catalytic mechanism were suggested, and a ‘K-acid’ bifunctional process may be a critical factor to the formation of anisole.
Graphical AbstractUnder catalysis of KH2PO4/Al2O3, phenol and methanol was activated by K and Al sites respectively. Anisole yield decreased with increasing space velocity, increased with increasing methanol fraction, and appeared a maximum value with increasing temperature.Figure optionsDownload as PowerPoint slide
Journal: Chinese Journal of Catalysis - Volume 37, Issue 5, May 2016, Pages 720–726