The one-step synthesis of methyl acrylate (MA) via the aldol condensation of methyl acetate (Ma) and formaldehyde (FA) has garnered considerable attention recently. Nevertheless, expensive Cs-based catalysts dominate this field, and challenges exist with alternative alkali metal-based catalysts. Herein, the K/Beta catalyst was tailored for the catalytic transformation of methyl acetate and formaldehyde into methyl acrylate. A series of bifunctional catalysts with varied acid–base characteristics were prepared through the introduction of the alkali metal K on the acidic Beta zeolite support. Unprecedentedly high methyl acrylate space time yield (5.95 mmol/h/g_Cat) has been achieved on the K-type catalyst, with a 35.6% methyl acetate conversion and 83.7% methyl acrylate selectivity. The physicochemical properties of the prepared K/Beta catalyst were fully characterized by ICP, XRF, N₂ adsorption–desorption isotherm, NH₃-TPD, CO₂-TPD, Py-IR, XRD, and XPS. The distribution and evolution of potassium species on catalysts having different K loadings have been investigated. The correlation between the acid–base properties of K/Beta catalysts and their catalytic performance on the aldol condensation was revealed. In addition, the effects of reaction parameters and catalyst preparation conditions on the catalytic performance were systematically researched, and the corresponding optimal conditions for K/Beta catalyst have been proposed. The kinetics of aldol condensation reactions of methyl acetate and formaldehyde on different catalysts were studied.

中文翻译：

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揭示 K 物种对丙烯酸甲酯合成中 K/β 的酸碱特性的影响


通过乙酸甲酯 （马） 和甲醛 （FA） 的羟醛缩合一步法合成丙烯酸甲酯 （MA） 近年来引起了广泛关注。然而，昂贵的 Cs 基催化剂在该领域占据主导地位，而替代碱金属基催化剂也存在挑战。在此，K/β催化剂是为乙酸甲酯和甲醛催化转化为丙烯酸甲酯而定制的。通过在酸性 β 分子筛载体上引入碱金属 K，制备了一系列具有不同酸碱特性的双功能催化剂。在 K 型催化剂上实现了前所未有的高丙烯酸甲酯时空产率 （5.95 mmol/h/g_Cat），乙酸甲酯转化率为 35.6%，丙烯酸甲酯选择性为 83.7%。通过 ICP、XRF、N₂ 吸附-脱附等温线、NH 3-TPD、CO_2-TPD、Py-IR、XRD 和 XPS 对所制备的 K/Beta 催化剂的物理化学性质进行了充分表征。已经研究了钾种类在具有不同 K 负载量的催化剂上的分布和演变。揭示了 K/β 催化剂的酸碱性质与其对羟醛缩合的催化性能之间的相关性。此外，系统研究了反应参数和催化剂制备条件对催化性能的影响，并提出了相应的 K/Beta 催化剂最佳条件。研究了乙酸甲酯和甲醛在不同催化剂上的羟醛缩合反应的动力学。