激光促进丁醇裂解表面反应机理

Mechanism of Laser Stimulated n-Butanol Cracking Surface Reaction

利用红外光谱和激光表面反应技术,研究了丁醇在SiO_2、γ-Al_2O_3和Fe_2O_3表面上的激光表面反应机理。根据不同固体表面和不同激发模式只影响激光表面反应的能量利用率而反应产物分布类同的实验结果,确定了丁醇在固体表面上的吸附态及受激吸附态分子内键与键间的能量传递是决定反应产物选择性的主要因素。

Infrared spectroscopy chemisorption and pulse CO2 laser techniques have been used to investigate the title reaction on the surfaces of SiO2, γ-Al2O3 and Fe2O3 at room temperature and atmospheric pressure. Experimental results revealed that the reaction of n-butanol cracking occured on the surface with the help of a peculiar frequency laser which excites the solid surface bonds or the C -O and C -C bonds in the adsorbed n- butanol molecules. The products of this reaction are ethane, ethene. acetylene, propylene, 1-butene and 2-butene. The efficiency of laser photon energy characterized by the n-butanol conversion depends strongly on the solid materials and on the excitation modes. It decreases in the order of SiO2>γ-Al2O3>Fe2O3. In relation to the excited bonds it decreases in the order of M-O bond> C-O bond> C-C bond. The product selectivity depends essentially on the chemisorption state of n-butanol and on the energy transfer from the excited bond to other bonds in the adsorbed n-butanol molecules. For three solid materials and three excitation modes, the product distributions are much the same. The critical step is the decomposition of the adsorbed n-butanol molecules to from some spieces on the solid surface with the help of a peculiar frequency laser. The energy transfer from the excited bond to other bonds in the adsorbed n- butanol molecule complys with the approaching principle of the vibrational frequency. The rupturing probability of the bonds in the excited n-butanal molecules is in inverse proportion to the bond energy.