Abstract

In this work, the protons of the Keggin heteropolyacids were exchanged by Lewis acid metal cations generating salts that were evaluated as catalysts on the β-pinene etherification with alkyl alcohols. The Fe(III) phosphotungstate salt (i.e. FePW₁₂O₄₀) was the most active and selective catalyst toward the formation of α-terpinyl methyl ether, the main reaction product. The activity of FePW₁₂O₄₀ catalyst was higher than their precursors of synthesis (i.e. H₃PW₁₂O₄₀, Fe(NO₃)₃), other Fe(III) heteropoly salts (i.e. FePMo₁₂O₄₀ and Fe_4/3SiW₁₂O₄₀), and heteropoly salts of different Lewis acids (i.e. AlPW₁₂O₄₀, Cu₃(PW₁₂O₄₀)₂). The effects of the main variables of reaction such as temperature, catalyst load, and alcohol nature were assessed. The Fe(III) cation, as well as the phosphotungstate anion, showed to be essential to the formation of the goal-product (α-terpinyl alkyl ether).

Graphic abstract

中文翻译：

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路易斯酸金属阳离子交换杂多盐作为β-pine烯醚化反应的催化剂

摘要

在这项工作中，Keggin杂多酸的质子被路易斯酸金属阳离子交换，生成了盐，这些盐被评估为用烷基醇将β-pine烯醚化的催化剂。Fe（III）磷钨酸盐（即FePW ₁₂ O ₄₀）是形成主要反应产物α-叔丁基甲基醚的最具活性和选择性的催化剂。FePW ₁₂ O ₄₀催化剂的活性高于其合成前体（即H ₃ PW ₁₂ O ₄₀，Fe（NO ₃）₃），其他Fe（III）杂多盐（即FePMo ₁₂ O ₄₀和Fe _4/3）SiW ₁₂ O ₄₀）和不同路易斯酸的杂多盐（即AlPW ₁₂ O ₄₀，Cu ₃（PW ₁₂ O ₄₀）₂）。评估了反应的主要变量如温度，催化剂负载和醇性质的影响。Fe（III）阳离子以及磷钨酸根阴离子显示出对目标产物（α-叔丁基烷基醚）形成至关重要。

图形摘要