Synthesis of micro-mesoporous TS-1 zeolite and its green catalytic oxidation of p-diethylbenzene

The micro-mesoporous TS-1 catalyst was synthesized by directly introducing NaOH during the synthesis of zeolite. As the first choice for many oxidation reactions, TS-1/H2O2 catalytic system is an environmentally friendly reaction system. However, the number and mechanism of Ti active sites participating in the reaction in TS-1 zeolite are seldom studied so far. Using TS-1 zeolite with and without NaOH as catalyst, p-diethylbenzene (PDEB) was oxidized in batch reactor to prepare p-ethylacetophenone and 1-(4-ethylphenyl)-1-ethanol. Reaction conditions including solvent, additives, temperature, time, dosage and oxidant were explored. The optimum reaction conditions, the conversion of PDEB was 27.7 % and the total selectivity was 74.5 % over TS-1-NaOH zeolite catalyst, where the selectivity of p-ethylacetophenone and 4-ethyl-α-methylbenzyl alcohol was 33.4 % and 41.1 %, respectively. Introducing mesoporous structure reduces the mass transfer resistance of the reaction and improves the selectivity of the target product. Based on the free radical reaction mechanism and the oxidative decomposition process of H2O2, it is inferred that the oxidation mechanism of PDEB in H2O2 system is a free radical reaction with the participation of •O2−.