论文部分内容阅读
由Rh/V_2O_3催化剂制备过程的红外光谱测定发现,酸性的RhCl_3·3H_2O溶液浸渍V_2O_3制备的催化剂上有 VOCl_2·5H_2O生成,VOCl·5H_2的低温脱水过程是可逆的;在高温下(300℃),VOCl_2发生歧化生成稳定的 VOCl和挥发性的VOCl_3,少量的VOCl_2·5H_2O添加到 Rh/SiO_2上可使催化剂的活性和生成 C-含氧化物的选择性明显提高,当钒促进的 Rh/SiO_2催化剂的H_2还原温度适当升高时,催化剂上生成C-含氧化物的选择性明显提高,同时伴随着催化剂上CO吸附的 IR 谱带强度明显下降,表明钒的化合物部分地覆盖了金属铑的表面,可能起着促进剂的作用。
The results showed that VOCl_2 · 5H_2O was formed on the catalyst prepared by impregnating V_2O_3 with acidic RhCl_3 · 3H_2O solution. The dehydration process of VOCl · 5H_2 was reversible at high temperature (300 ℃) Disproportionation of VOCl_2 produces stable VOCl and volatile VOCl_3. The addition of a small amount of VOCl_2 · 5H_2O to Rh / SiO_2 significantly increases the activity of the catalyst and the selectivity of C-oxide formation. When vanadium-promoted Rh / SiO_2 catalyst H 2 reduction temperature increased properly, the selectivity of C-oxide formed on the catalyst increased obviously, and the intensity of IR band decreased obviously along with the adsorption of CO on the catalyst, which indicated that the vanadium compound partially covered the surface of metal rhodium , May play a role of accelerator.