1,3-丁二烯(以下简称丁二烯)作为化工的重要有机中间体, 在石油以及橡胶工业有着广泛的用途. 以乙醇为原料生产丁二烯能够解决生产原料不可再生的问题, 所以受到越来越多的关注. 本工作采用SBA-15为载体, 硝酸盐为氧化物前驱体, 含氮有机物为助剂, 通过水热合成法制备了催化剂, 并探究了乙醇合成丁二烯反应过程中, 乙醇转化率、丁二烯收率与催化剂酸碱性的关系. 具体来说, 使用三聚氰胺(M)、三聚氰酸(Ma)、1,10-菲啰啉(Pm)、咪唑(Im)和1,3,5-三嗪(St)为含氮助剂, 制备了Zn-Zr/SBA-15＋X催化剂. 通过对催化剂的活性评价, 计算得到乙醇脱氢和脱水、乙醛缩合、Meerwein-Ponndorf-Verley (MPV)反应的活性. 根据反应活性和丁二烯收率与催化剂酸碱性(酸碱强度和含量)的变化关系, 发现适当数量的弱酸(0.022 mmol·g⁻¹)、中酸(0.078 mmol·g⁻¹)、中碱(0.055 mmol·g⁻¹)和强碱(0.056 mmol·g⁻¹)有助于乙醇脱氢反应的发生, 过量的弱酸和中酸将导致乙醇的脱水反应. 中等数量的中酸(0.078 mmol·g⁻¹)和中碱(0.055 mmol·g⁻¹)有利于乙醛缩合和MPV反应的发生. 丁二烯收率与乙醛缩合活性和MPV活性关联较大. 三聚氰胺改性的催化剂(Zn-Zr/SBA-15＋M)的弱酸、中酸、中碱和强碱含量符合以上的最优数量, 因此催化性能最优异: 乙醇转化率为99.5%, 丁二烯选择性为65.5%, 丁二烯产能达到了0.45 g_BD·g_cat⁻¹·h⁻¹.

1,3-Butadiene (hereinafter referred to as butadiene), as an important organic intermediate in the chemical industry, has a wide range of uses in the petroleum and rubber industries. Using ethanol as raw material to produce butadiene can solve the non-renewable problem of raw materials, so it has received more and more attention. In this paper, catalysts were hydrothermally synthesized by using SBA-15 as the support, nitrate as the oxide precursor, and nitrogen-containing organic compounds as the additive. And then, the relationship between catalytic performance (ethanol conversion and butadiene yield) and the acid-base properties of catalysts was explored in the synthesis of butadiene from ethanol. Specifically, we used melamine (M), cyanuric acid (Ma), 1,10-phenanthroline (Pm), imidazole (Im), and 1,3,5-triazine (St) as nitrogen-containing additives for the preparation of Zn-Zr/SBA-15＋X catalysts. Through the activity evaluation of the catalysts, the activities of ethanol dehydrogenation and dehydration, acetaldehyde condensation, and Meerwein-Ponndorf-Verley (MPV) reactions were calculated. Then, by analyzing the dependence of these activities and butadiene yield on the acidity and basicity (the strength and number of acidic/basic sites) of catalysts, we found that appropriate amounts of weak acid (0.022 mmol·g⁻¹), moderate acid (0.078 mmol·g⁻¹), moderate base (0.055 mmol·g⁻¹), and strong base (0.056 mmol·g⁻¹) are helpful for the ethanol dehydrogenation, whereas excess amount of weak acid and moderate acid will lead to the ethanol dehydration. Appropriate amounts of moderate acid (0.078 mmol·g⁻¹) and moderate base (0.055 mmol·g⁻¹) will favor the acetaldehyde condensation and MPV reactions. The butadiene yield is closely related to the activities of acetaldehyde condensation and MPV. The melamine-modified catalyst (Zn-Zr/SBA-15＋M) has the optimum amounts of weak acid, moderate acid, moderate base, and strong base in accordance with the above quantities, resulting in the best catalytic performance: 99.5% conversion of ethanol, 65.5% selectivity of butadiene, and 0.45 g_BD·g_cat⁻¹·h⁻¹ of butadiene productivity.