Ethanol to n‐butanol conversion is a process that can increase the carbon number of alcohols by coupling. There is increasing interest in the mechanisms for n‐butanol production in a simple step through the effective use of bifunctional acid–base catalysts. In this context, commercial hydroxyapatite (HAP) and two synthetized model supported catalysts, Ca/Al₂O₃ and Ca‐P/Al₂O₃, were used in bioethanol condensation. Characterization and acid–base sites were considered, and Fourier‐transform infrared (FTIR) spectroscopy and diffuse reflectance infrared Fourier‐transform spectroscopy–mass spectrometry (DRIFT‐MS) reactivity tests were performed in situ, as a first approximation to design a sustainable catalytic process rationally, and with the aim of understanding the process at the catalytic surface. The results indicated that the reactions occur at a large range of temperatures (200–450 °C). Hydroxyapatite and Ca/Al₂O₃ have similar basic sites (low and medium) and Ca‐P/Al₂O₃ presented the strongest Brönsted and Lewis combined acid sites. Three major reactions were identified: non‐oxidative dehydrogenation, aldol condensation, and intermolecular reduction, associated with the basic‐acid sites Ca‐O‐Ca/Ca‐O‐P/Ca‐O‐Al. Side reactions also occur involving different acid sites related to Lewis alumina centers favoring ethylene or diethyl‐ether production. © 2020 Society of Industrial Chemistry and John Wiley & Sons Ltd

中文翻译：

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乙醇缩合生产正丁醇的钙基双功能酸碱模型催化剂

乙醇转化为正丁醇的过程可以通过偶联增加醇的碳数。通过有效使用双功能酸碱催化剂，通过简单的步骤，对正丁醇生产机理的兴趣日益浓厚。在这种情况下，商业羟基磷灰石（HAP）和两种合成的模型载体催化剂Ca / Al ₂ O ₃和Ca-P / Al ₂ O ₃用于生物乙醇缩合。表征和酸碱场所被认为是，和傅立叶变换红外光谱（FTIR）和漫反射红外傅里叶变换光谱法-质谱法（DRIFT-MS）反应试验进行原位，这是合理设计可持续催化过程的第一步，目的是了解催化表面的过程。结果表明，反应在较大的温度范围（200–450°C）下发生。羟基磷灰石和Ca / Al ₂ O ₃具有相似的碱性位点（低和中），而Ca-P / Al ₂ O ₃展示了最强的布朗斯台德和路易斯综合酸位。确定了三个主要反应：非氧化脱氢，羟醛缩合和分子间还原，与碱性酸位点Ca-O-Ca / Ca-O-P / Ca-O-Al相关。副反应也会发生，涉及与路易斯氧化铝中心有关的不同酸位，有利于乙烯或二乙醚的生产。©2020工业化学学会和John Wiley＆Sons Ltd