Ảnh hưởng của dung môi đến tính bền của xúc tác phức coban dị thể trong phản ứng oxi hóa chọn lọc của sec-phenetyl ancol

Abstract

In this work the effect of solvent and N-hydroxyphtalimide (NHPI) on the cobalt leaching and on the activity and the stability of silica based cobalt (II) interphase catalyst for aerobic oxidation of sec-phenethyl alcohol (a-methylbenzyl alcohol) was investigated. The solvents that were used in this work are CH₃CN and CH₃COOC₂H₅. It has been found that under similar reaction conditions, with CH₃CN as solvent, the system consisting NHPI combined with Co/SBA-15 lead a sec-phenethyl alcohol conversion of 36.4% after 9 h of reaction while in the presence of CH₃COOC₂H₅ as solvent, the sec-phenethyl alcohol was completely converted after just 5 h of reaction. Recycling  experiments indicates that in CH₃CN, activity of catalyst recycling decreased significantly in fist recycle. On the other hand, in  CH₃COOC₂H₅ as solvent, no loss of the catalytic activity was observed after at least 2 catalytic cycles of the phenethyalcohol oxidation. In the presence of both NHPI and sec-phenethyl alcohol in CH₃CN, the quantity of Co leached is very high. On the contrary, in CH₃COOC₂H₅, the leaching of Co is neglisible in any cases.