EFFECT OF Si/Al RATIOS AND POTASSIUM ADDITION ON ACRYLIC ACID PRODUCTION FROM LACTIC ACID ON Y-ZEOLITE CATALYSTS MIXED WITH ALUMINA

Abstract

In this research, the effect of different potassium loading over HY100 zeolite catalysts at 0, 2, 4, 6 and 8 wt.% prepared by incipient wetness impregnation method was studied. In addition, the effect of Si/Al molar ratios (15, 100 and 500) of HY zeolite modified with potassium at 6 wt.% was also investigated. Furthermore, the effect of support ratios of Al2O3 and HY zeolite modified with potassium 6 wt.% was studied as follows: 3:1, 1:1 and 1:3. All catalysts were tested in lactic acid dehydration reaction at 340 °C of reaction temperature under atmospheric pressure and characterized by various techniques. From the results, it was found that HY zeolite modified with different potassium loading, Si/Al molar ratios of HY zeolite and support ratios of Al2O3 and HY zeolite affected the catalytic activity in lactic acid dehydration reaction, evidenced by characterization results. Among all the catalysts, the HY zeolite with Si/Al molar ratios of 100 and modified with potassium at 6 wt.% represented the best catalyst for lactic acid dehydration with 100% conversion and 45.5% selectivity for acrylic acid as well as the lowest acetaldehyde selectivity due to the suitability of total acidity and basicity of the catalyst. However, the catalyst with too high Al2O3 content caused the structural collapse, high strong acid sites and high coke deposition resulting in the lowest catalytic performance. The catalytic results indicated that potassium modification of HY zeolite could improve acrylic acid selectivity and reduce acetaldehyde selectivity.