Catalytic Oxidation Of P-chlorotoluene To P-chlorobenzaldehyde Over Co-TiO₂-SiO₂ Aerogel And ZIF-67（Co）

P-chlorobenzaldehyde is a kind of important medicines, dye intermediates and fine chemical products. The general production in domestic is about 1000 t/a, which is far less than the domestic demand of about 3000 t/a, and users in some parts of the country mainly depends on imports. Therefore, to improve the yield of chlorobenzene formaldehyde, the development of heterogeneous catalyst with high activity and selectivity has very high research value and industrial significance.Herein, several kinds of catalysts have been used in catalytic oxidation of p-chlorotoluene. The main contents of the paper are as following:(1) Co-TiO2-SiO2 aerogel and ZIF-67(Co) were synthesized in this article and the obtained samples were characterized by N2 adsorption/desorption measurement, Powder X Ray diffraction (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and Thermogravimetric differential thermal analysis (TG-DTA).(2) Co-TiO2-SiO2 aerogel and ZIF-67(Co) were used in the oxidation reaction of p-chlorotoluene, and the influence of various parameters including catalysts, solvents, oxidants, reaction temperature and reaction time on the yield of p-chlorobenzaldehyde was studied.When using Co-TiO2-SiO2 aerogel (90 mg) as catalyst, acetic acid as solvent (5 mL), the hydrogen peroxide as oxidant (5 mL), reaction temperature 100 ℃ and reaction time 10 h, the 53.6% p-chlorotoluene conversion and the selectivity of 100% toward p-chlorobenzaldehyde were obtained.(3) When using ZIF-67(Co) (50 mg) as catalyst, acetic acid as solvent (12 mL), the hydrogen peroxide as oxidant (5 mL), reaction temperature is 100 ℃, reaction time is 8h, the 75.3% p-chlorotoluene conversion and 92.9% selectivity to p-chlorobenzaldehyde were achieved.