Prins condensation of formaldehyde with propylene to form 3‐buten‐1‐ol is investigated using microporous solid acid catalysts. Zn/H‐beta shows high conversion but leads to a broad product distribution composed primarily of pyrans. Mechanistic studies revealed that 3‐buten‐1‐ol reacts via Prins cyclization or dehydrate to 1,3‐butadiene that further reacts with formaldehyde via a hetero‐Diels–Alder reaction. These secondary reactions are suppressed over ZSM‐5 catalysts: 3‐buten‐1‐ol is the predominant product over H‐ZSM‐5 zeolite under all conditions investigated. 3‐Buten‐1‐ol selectivity of up to 75 % is achieved. In a second step 3‐buten‐1‐ol dehydrates at temperatures as low as 423 K, forming 1,3‐butadiene. Although Brønsted acid sites are the primary catalytic sites, ion exchange of Zn^II increases the overall rate and 3‐buten‐1‐ol selectivity. H‐ZSM‐5 showed significant differences in reactivity and selectivity as a function of the Si/Al ratio; optimal catalytic properties were observed within Si/Al=40–140.

中文翻译：

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沸石催化的甲醛-丙烯缩聚物的缩合

使用微孔固体酸催化剂研究了甲醛与丙烯的缩聚反应，形成3-丁烯-1-醇。Zn /H-β显示出高转化率，但导致主要由吡喃组成的广泛产品分布。机理研究表明，3-丁烯-1-醇通过Prins环化反应或脱水成1,3-丁二烯，然后通过杂Diels-Alder反应与甲醛进一步反应。这些次级反应在ZSM-5催化剂上得到抑制：在所有研究的条件下，3-丁烯-1-醇是H-ZSM-5沸石的主要产物。达到了最高75％的3-丁烯-1-醇选择性。第二步，3-丁烯-1-醇在低至423 K的温度下脱水，形成1,3-丁二烯。尽管布朗斯台德酸位点是主要的催化位点，但Zn ^II的离子交换提高了总转化率和3-丁烯-1-醇的选择性。H‐ZSM-5的反应性和选择性显着不同，这是Si / Al比的函数。在Si / Al = 40-140范围内观察到最佳的催化性能。