Zeolites are porous aluminosilicate materials that find various applications in the chemical industry in separations, catalysis, ion exchange, and so forth. However, despite their widespread use, the reaction mechanisms occurring during zeolite growth are still unclear. Herein, we use density functional theory calculations to gain insights into the thermodynamics of oligomerization, which constitute the initial steps of zeolite growth. By taking into consideration solvent and temperature effects, our results demonstrate that the growth of aluminosilicate systems is significantly more exothermic than their pure silicate counterparts. Under pH neutral conditions, water prefers to dissociate on the early‐growth‐stage aluminosilicate complexes rather than desorb, thus generating potential Brønsted acid sites on the oligomers. Additionally, (alumino)silicate growth pathways are evaluated in the presence of Na⁺ cation, as well as the Ca²⁺ cation for the pure silicate pathway. The presence of cations increases the exothermicity of growth, with Ca²⁺ exhibiting the most energetically favorable growth environment for the silicate systems. Importantly, we demonstrate through reaction extent analysis that the presence of cations modulates the speciation of the formed oligomers, with Na⁺ favoring linear species in addition to the generally preferred cyclic ones. Overall, this work provides a fundamental understanding of the thermodynamics of complex reaction paths that occur during early stages of zeolite growth and suggests that the initial growth steps can have significant impact on the final zeolite structure.

中文翻译：

---

通过第一原理计算了解初始沸石低聚步骤

沸石是多孔铝硅酸盐材料，其在化学工业中在分离，催化，离子交换等方面具有各种应用。然而，尽管它们被广泛使用，但在沸石生长过程中发生的反应机理仍不清楚。在这里，我们使用密度泛函理论计算来获得对低聚热力学的认识，而低聚是构成沸石生长的初始步骤。通过考虑溶剂和温度的影响，我们的结果表明，硅铝酸盐体系的生长比纯硅酸盐体系的放热要大得多。在pH中性条件下，水倾向于在早期生长阶段的铝硅酸盐络合物上解离，而不是解吸，从而在低聚物上产生潜在的布朗斯台德酸位。另外，⁺阳离子，以及纯硅酸盐途径的Ca ²⁺阳离子。阳离子的存在增加了生长的放热性，其中Ca ²⁺对硅酸盐体系显示出在能量上最有利的生长环境。重要的是，我们通过反应程度分析证明，阳离子的存在调节形成的低聚物的形态，除了通常优选的环状化合物外，Na ^+还有利于线性物质。总的来说，这项工作提供了对在沸石生长的早期阶段发生的复杂反应路径的热力学的基本理解，并表明初始的生长步骤可能会对最终的沸石结构产生重大影响。