Mechanism of 1,2-dichloroethane dehydrochlorination on the acid sites of oxide catalysts as studied by IR spectroscopy
Mechanism of 1,2-dichloroethane dehydrochlorination on the acid sites of oxide catalysts as studied by IR spectroscopy
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红外光谱研究氧化物催化剂酸性位点上1,2-二氯乙烷脱氯化氢机理
DOI：
10.1134/s0023158411020169
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发表时间：
2011
影响因子：
1.1
通讯作者：
E. Paukshtis
中科院分区：
文献类型：
--
作者：
A. Shalygin;L. Malysheva;E. Paukshtis
用傅里叶变换红外光谱法研究了1，2-二氯乙烷在HZSM-5和γ-Al_2O_3分子筛上的吸附行为。确定了1，2-二氯乙烷在催化剂的Brønsted酸中心和刘易斯酸中心上的吸附形式及其转化产物。采用原位傅里叶变换红外光谱法研究了1，2-二氯乙烷在催化剂表面的转化动力学。结果表明，1，2-二氯乙烷在100°C时仍在γ-Al_2O_3的刘易斯位上发生脱氯化氢反应，而在HZSM-5分子筛的布朗斯特位上，该反应仅在200°C时发生.结果表明，在催化剂的刘易斯酸位上，氯乙烯发生低聚反应，中间产物为二聚体（1，3-二氯-2-丁烯），而在HZSM-5分子筛的布朗斯特位上，未观察到1，3-二氯-2-丁烯的生成。提出了1，2-二氯乙烷在刘易斯酸和布朗斯特酸中心的转化机理。
The adsorption of 1,2-dichloroethane on zeolite HZSM-5 and γ-Al2O3at temperatures from 25 to 400°C was studied by Fourier transform IR spectroscopy. The forms of adsorbed 1,2-dichloroethane and the products of its conversion at the Brønsted and Lewis acid sites of catalysts were identified. The kinetics of 1,2-dichloroethane conversion on the surface of catalysts was studied by in situ Fourier transform IR spectroscopy. It was demonstrated that 1,2-dichloroethane was dehydrochlorinated at the Lewis sites of γ-Al2O3even at 100°C, whereas the reaction came into play at the Brønsted sites of zeolite HZSM-5 only at 200°C. It was found that, at the Lewis acid sites of catalysts, the resulting vinyl chloride underwent oligomerization with the intermediate formation of a dimer (1,3-dichloro-2-butene), whereas the formation of 1,3-dichloro-2-butene at the Brønsted sites of zeolite HZSM-5 was not observed. The mechanisms of 1,2-dichloroethane conversions at Lewis and Brønsted acid sites were proposed.