Abstract Infrared spectra of dealuminated high silica MFI zeolites were measured to elucidate the structure of silanol groups active for conversion of 1-butene to propene. The OH groups were replaced by OD groups to have clear vibrational spectra. Two sharp bands and one broad band were observed; isolated silanol at 2746 cm −1 , terminal silanol at 2725 cm −1 , and hydrogen-bonded silanols centered at 2570 cm −1 composed of more than one components. Based on the response of these bands to Na poisoning and pyridine adsorption together with the correlation with catalytic results, we propose that the active sites for propene formation are one of the terminal silanol groups and one of the hydrogen-bonded silanol groups in a silanol nest. The active hydrogen-bonded silanol groups are the one whose O atom is hydrogen-bonded to adjacent two H atoms in the silanol nest. Graphic Abstract

中文翻译：

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脱铝高二氧化硅 MFI 沸石上硅烷醇基团的红外研究，以将不同类型的硅烷醇基团与 1-丁烯转化为丙烯的活性相关联

摘要 测量脱铝高二氧化硅 MFI 沸石的红外光谱，以阐明对 1-丁烯转化为丙烯具有活性的硅烷醇基团的结构。OH 基团被 OD 基团取代以获得清晰的振动光谱。观察到两条尖锐条带和一条宽条带；在 2746 cm -1 处分离出硅烷醇，在 2725 cm -1 处分离出末端硅烷醇，在 2570 cm -1 处为中心的氢键合硅烷醇由一种以上的组分组成。基于这些带对钠中毒和吡啶吸附的响应以及与催化结果的相关性，我们提出丙烯形成的活性位点是硅烷醇巢中的末端硅烷醇基团之一和氢键合硅烷醇基团之一。 . 活性氢键合硅烷醇基团是指其 O 原子与硅烷醇巢中相邻的两个 H 原子形成氢键合的基团。图形摘要