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利用原位漫反射傅里叶红外光谱(DRIFTS),考察了室温下羰基硫(COS)在经氨气和有机胺预吸附的α-Fe_2O_3上的非均相反应,并同时比较了氨气和不同有机胺(甲胺、三甲胺、三乙胺、苯胺、吡啶和吡咯)对反应活性的影响及其反应动力学.结果表明,经碱性物质预吸附后,COS可在α-Fe_2O_3表面发生氧化反应,主要产物为气态CO_2、表面HCO_3~-、表面CO_3~(2-)和表面SO_4~(2-),且α-Fe_2O_3表面预吸附的碱性物质大大提高了COS在α-Fe_2O_3上的反应能力,在碱性物质的影响中,甲胺对反应的促进能力最大,相比纯α-Fe_2O_3反应的反应活性提高了约4.5倍,然而苯胺和吡咯对COS的反应影响不是很明显.观察到的不同碱性物质对COS的转化能力依次为:甲胺>三甲胺>氨气>三乙胺>吡啶>吡咯>苯胺≈纯样品,受碱性物质的影响,COS的反应级数由一级转变为二级.此外,研究也发现碱性物质的覆盖度和表面吸附水对COS转化能力存在一定的影响.这些实验结果表明在碱性物质存在下,表面M―O-是COS在α-Fe_2O_3发生氧化反应的关键活性位点,对反应活性的贡献较大,并在此基础上探讨碱性条件下COS的反应转化机制.
In situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) was used to investigate the heterogeneous reaction of carbonyl sulfide (COS) on α-Fe_2O_3 pre-adsorbed by ammonia and organic amines at room temperature. The effects of ammonia and The effects of different organic amines (methylamine, trimethylamine, triethylamine, aniline, pyridine and pyrrole) on the reactivity and their reaction kinetics were studied. The results showed that COS could be formed on the surface of α-Fe 2 O 3 after pre-adsorption with alkaline substances The main products are gaseous CO_2, HCO_3 ~ -, CO_3 ~ (2-) and SO_4 ~ (2-), and the pre-adsorbed alkaline substances on the surface of α-Fe_2O_3 greatly improve the catalytic performance of COS on α-Fe_2O_3 Methylamine had the highest ability to promote the reaction, which was about 4.5 times higher than that of pure α-Fe 2 O 3. However, the effect of aniline and pyrrole on COS was not obvious. The observed conversions of different basic substances to COS are as follows: methylamine> trimethylamine> ammonia gas> triethylamine> pyridine> pyrrole> aniline ≈ pure sample. Due to the influence of alkaline substances, the reaction order of COS consists of A shift to two.In addition, the study also found that the coverage of alkaline substances and surface adsorption of water on the C OS conversion ability.These experimental results show that in the presence of alkaline substances, surface M-O- is the key active site for the oxidation of COS in α-Fe 2 O 3 and contributes more to the reactivity Based on the basic conditions of COS reaction mechanism of conversion.