Mo-Ce/SiO_2催化剂上甲醇氧化制甲醛的动力学与机理

The Kinetics and Mechanism for Oxidation of Methanol to Formaldehyde over Mo-Ce/SiO_2 Catalyst

用玻璃外循环无梯度反应器研究了Mo-Ce/SiO_2催化剂的甲醇氧化制甲醛的动力学。吡啶吸附的红外光谱鉴别出催化剂Lewis酸的存在。红外光谱证实甲醇在催化剂上发生化学吸附。用脉冲色谱法测定了甲醇及甲醛的吸附热。随着甲醛分压的增加,甲醇氧化制甲醛的速度随之减小。进行了催化剂被甲醇还原及还原催化剂用O_2再氧化的脉冲实验。甲醇氧化的动力学服从甲醇及甲醛吸附的Redox机理方程。

The kinetics of oxidation of methanol to formaldehyde has been investigated by the glass recirculation gradientless reactor over Mo-Ce/SiO2 catalyst. The presence of Lewis acid was discriminated by the infrared spectroscopic method of pyridine adsorption on the catalyst. The chemisorption of methanol on catalyst was shown by the infrared spectra. The heats of adsorption of methanol and formaldehyde were determinated with the pulse chromatography method. The rate of oxidation of methanol to formaldehyde decreased with increasing pressure of formaldehyde. Mo-Ce/SiO2 catalyst was reduced by the methanol and the reducing catalyst was oxidized by the oxygen with pulse experiments. The kinetics of oxidation of methanol obeyed the equation of redox mechanism with adsorption of methanol and formaldehyde.