Wenzhou Zhong

A non-nitric acid method of adipic acid synthesis: organic solvent- and promoter-free oxidation of cyclohexanone with oxygen over hollow-structured Mn/TS-1 catalysts

A novel hollow-structured Mn/TS-1 catalyst has been reported as a non-nitric acid route for adipic acid production from oxidative cleavage of cyclohexanone. The method generates adipic acid in high yields with molecular oxygen under organic solvent- and promoter-free conditions. The hollow nature of the catalyst with large intra-particle voids facilitates the diffusion of bulky molecules to the internal catalytic site and increases the catalyst activity. The advantage of this catalyst is its reusability with almost consistent reactivity, thereby making it viable for industrial applications.

A novel route for preparation of Mn-containing hollow framework TS-1, and its selective allylic oxidation of cyclohexene

A new manganese-containing hollow framework TS-1 (MTS-1) was prepared via simple recrystallization of traditional TS-1 in the presence of tetrapropylammonium hydroxide (TPAOH) and manganese(III)–acetylacetonate, and its catalytic performance was tested for aerobic oxidation of cyclohexene without any solvents. This hollow bimetal TS-1 catalyst is more active than catalysts containing Mn or Ti solely; the formation of metal framework sites may be responsible for increased activity. The characterization techniques such as UV-vis, FT-IR, Raman, XRD, N2-adsorption, TEM, and XPS confirm the incorporation of Mn and Ti in the zeolite framework sites. This hollow catalyst shows high catalytic activity and stability (ten cycles) in the oxidation of cyclohexene, and demonstrates the potential of TS-1 catalysts for use in aerobic oxidations.

Consideration of roles of commercial TiO2 pigments in aromatic polyurethane coating via the photodegradation of dimethyl toluene-2,4-dicarbamate in non-aqueous solution

Dimethyl toluene-2,4-dicarbamate (2,4-TDC) was selected as a model compound for aromatic polyurethane to investigate the photo-chemical behavior of commercial TiO2 pigments in non-aqueous solution. The UV–Visible spectrometry analysis results showed that the UV-shielding ability of the rutile TiO2 pigment was better than that of the anatase TiO2 pigment. Photodegradation experiments suggested that the photodegradation of 2,4-TDC was retarded by rutile TiO2 pigment, while accelerated by anatase TiO2 pigment. With the help of the degradation intermediates during the photodegradation process and calculated data, such as point charges and bond length, the preliminary photodegradation mechanism of 2,4-TDC was also briefly elucidated, including the addition of hydroxyl radicals and the cleavage of the carbamate side chain. Additionally, the photodegradation of 2,4-TDC was used to evaluate the photoreactivity of TiO2 pigments, this is proved to an efficient approach with potential application in industry.