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Gas phase acylation of guaiacol with acetic acid on acid catalysts
Applied Catalysis B: Environment and Energy ( IF 22.1 ) Pub Date : 2020-07-10 , DOI: 10.1016/j.apcatb.2020.119317
M.K. Montañez Valencia , C.L. Padró , M.E. Sad

Gas phase acylation of guaiacol on acid solids was studied using catalysts with different acid site density, nature and strength. The main products formed were acetovanillone, 2-acetoxyanisole and catechol using acetic acid as acylating reactant. The product distribution considerably changed with the catalyst nature. Catalysts with Lewis and Brønsted acid sites promoted both the O-acylation route (2-acetoxyanisole formation) and C-acylation route (acetovanillone formation) and formed catechol mainly by demethylation of guaiacol; catalysts with large pore size also favored catechol formation by a bimolecular disproportionation reaction. Catalyst deactivation took place, thus the coke formation was studied suggesting that the Lewis acid sites, responsible of catechol formation, were more affected by deactivation. The effect of reaction temperature, molar reactant ratio and the use of different acylating molecules on guaiacol conversion and products formation were also evaluated. HZSM-5 catalyst, 523 K and acetic acid were appropriate to promote C-acylation during gas phase guaiacol acylation.



中文翻译:

在酸催化剂上将愈创木酚与乙酸进行气相酰化

用不同酸位密度,性质和强度的催化剂研究了愈创木酚在酸性固体上的气相酰化反应。使用乙酸作为酰化反应物,形成的主要产物为乙酰香草醛,2-乙酰氧基苯甲醚和邻苯二酚。产物分布随催化剂性质而大大改变。具有路易斯酸和布朗斯台德酸位的催化剂既促进了O-酰化途径(2-乙酰氧基茴香醚的形成)又促进了C-酰化途径(乙酰香草醛的形成),并且主要通过愈创木酚的去甲基化作用而形成了邻苯二酚。大孔尺寸的催化剂还通过双分子歧化反应促进了邻苯二酚的形成。发生了催化剂失活,因此研究了焦炭的形成,这表明负责邻苯二酚形成的路易斯酸位受失活的影响更大。反应温度的影响 还评估了反应物的摩尔比以及不同酰化分子对愈创木酚转化率和产物形成的影响。HZSM-5催化剂,523 K和乙酸适用于在气相愈创木酚酰化过程中促进C-酰化。

更新日期:2020-07-18
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