| 摘要 |
Prepn. of 2-hydroxybenzonitrile (I) comprises gas phase dehydration of 2-hydroxybenzamide (II) using heterogeneous catalysis. The catalyst is pref. SiO2 gel treated with H3PO4 and is dried before use. Reaction is carried out at 200-400 degrees C and reduced pressure (esp. 20-40 mbar). The LHSV is 0.05-1 (esp. 0.1-0.5) hr<-1>. Pure (I) is recovered from the crude reaction mixt. by distn. |
