Vapor phase acylation of phenol with ethyl acetate over H3PO4/TiO2-ZrO2

ZrO2-TiO2 mixed oxides with a Ti and Zr molar ratio of 1/1 were prepared with and without surfactant by the sol–gel method. Catalysts containing 5–35% H3PO4 were prepared using these mixed oxides and the catalytic performance of each material for vapor phase acylation of phenol to 2-hydroxy acetophenone (2-HAP) was determined. During the reaction of phenol with ethyl acetate, 2-HAP was found to be the major product, when 4-hydroxy acetophenone was not detected in the product stream; phenylacetate (PA) and alkylated products were the minor products. In the best experimental conditions, the alkylated products were less than 0.5%. This reaction may represent an environmentally friendly alternative to use the ethyl acetate as the acylating reagent. The feed molar ratios of phenol/ethyl acetate were varied over a wide range (1–0.1), and the optimum feed ratio of phenol/ethyl acetate was 1:3. Space velocity employed in phenol acylation reported as WHSV (phenol) = 1.35 h−1. The acylation reactions were carried out in the temperature range of 473–673 K and the optimum H3PO4 content for acylation was 15 wt.% H3PO4.

Graphical abstractVapor phase acylation of phenol with ethyl acetate over 15 wt.% H3PO4/TiO2-ZrO2-surf has been investigated. In this reaction, 2-hydroxy acetophenone was found to be the major product when 4-hydroxy acetophenone was not detected in the product stream; phenyl acetate and alkylated products were the minor products. Figure optionsDownload full-size imageDownload as PowerPoint slide