The modified HZSM-5 zeolites via alkali-treated with various NaOH aqueous solution and supported iron oxide by impregnation technique was prepared, as proved by XRD, SEM, TEM, XPS, NH₃-TPD and ICP-OES to determine their phase structure, composition and surface character. These modified materials were tested for catalyzing solvent-free oxidation of toluene under mild conditions. The experimental results indicated that the alkali-treated HZSM-5 showed higher activity because of reduction of strong acidic sites on the surface. However, the alkali-treated HZSM-5 supported iron material exhibited high selectivity to benzaldehyde via promoting the oxidation of toluene or benzyl alcohol and limiting the further oxidation of benzaldehyde into phenol caused by lowing surface Brönsted acidity and introducing Fe red-ox sites.

通过XRD，SEM，TEM，XPS，NH _3验证了改性后的HZSM-5分子筛经各种NaOH水溶液碱处理和负载型氧化铁的浸渍工艺。-TPD和ICP-OES确定其相结构，组成和表面特性。测试了这些改性材料在温和条件下催化甲苯的无溶剂氧化反应。实验结果表明，经碱处理的HZSM-5具有较高的活性，因为其表面上的强酸性部位减少了。然而，经碱处理的HZSM-5负载铁材料通过促进甲苯或苄醇的氧化并限制苯甲醛进一步氧化为苯酚（由于降低的表面布朗斯台德酸度和引入Fe氧化还原位点）而对苯甲醛具有高选择性。