A composite material ZSM-5@Co-MOF containing Co-MOF and ZSM-5 was successfully prepared by steam-assisted crystallization of Co-MOF on the zeolite surface. Compared to physically mixing Co-MOF on the zeolite surfaces, Co-MOF nanosheets were uniformly attached to external surfaces of the ZSM-5 crystals because of the enhanced interaction between zeolite and Co-MOF in the composite. In addition, the Co-MOF was distributed as a nanosheet structure, and its dispersibility was greatly enhanced, in which this behavior led to more uniform distribution of the deposited active sites. Interestingly, the designed composite exhibited an excellent catalytic performance for the epoxidation of α-pinene with air. Compared to isolated Co-MOF and ZSM-5, high yield of the product (94.4%) was obtained over the 0.5ZSM-5@Co-MOF-150 composite due to the highly dispersed Co-MOF nanosheet. This opens up interesting prospects for developing new zeolite@MOF composite catalysts as efficient heterogeneous catalysts.

In view of the difficulty of efficient epoxidation of cyclooctene with molecular oxygen, we introduce the rare earth metal La element to synthesize an acidic bimetallic LaCo-MOF material, which has an excellent synergistic catalytic effect in the air epoxidation reaction of cyclooctene. Various characterization results prove that Co and La in the bimetallic LaCo-MOF-BTC-H material are not mixed physically, but co-exist in the MOF framework in the form of coordination with obvious interactions. Moreover, the introduction of the La element enhances the acidity of bimetallic LaCo-MOF-BTC-H material significantly. By exploring the effects of different metal ratios, different metal combinations, different crystallization temperatures and time on the material structure and reactivity, the synthesis conditions of the La2Co8-MOF-BTC-H material with the best catalytic performance are determined. Under the reaction conditions of 80 degrees C and 30 ml/min air flow rate, the conversion of cyclooctene could reach 96.2% after 5 h of reaction, and the selectivity of epoxy cyclooctane was as high as 98.7%. The La2Co8-MOF-BTC-H material showed good recyclable stability, and the catalytic activity did not decrease significantly after repeated-use 5 times.

This work has for the first time reported the construction of strong Lewis acidity through one route of pre-calcining octahedral Zr-MOF material, which was synthesized by the rotating hydrothermal crystallization method with regular octahedral structure, large specific surface area and very uniform particle size. After low-temperature calcination, the resulting material Zr-MOF-R-X-Cal did retain basically an intact structure of Zr-MOF-R precursor and became more hydrophobic, as characterized by XRD patterns, SEM/TEM images and WCA angles. More importantly, the surface Lewis acidity and Lewis acid ratio on the calcined materials were significantly enhanced. Thus-calcined materials have exhibited highly catalytic activity for selective isomeriza-tion of alpha-epoxypinane to campholenic aldehyde. As we know, campholenic aldehyde (CA) was an important intermediate for the production of sandalwood and drugs, and generally prepared by selective isomerization of alpha-epoxypinane on strong Lewis acid sites. Among the tested materials, Zr-MOF-R-300-Cal presented the best catalytic effect on this isomerization to obtain 95.9% conversion of alpha-epoxypinane and 82.4% selectivity of CA, much superior to the Zr-MOF-R precursor and those catalytic materials reported previously in the literature. This could be assigned with strong Lewis acidity and high Lewis acid content on the Zr-MOF-R-300-Cal material, as proven by NH3-TPD and pyridine-FTIR tests. In addition, the increase of surface hydrophobicity promoted surface diffuse, adsorption and mass transfer of substrate molecules. Notably, catalytic activity of the Zr-MOF-R-300-Cal material was not decreased a lot after repeated-use six times, indicative of its excellent stability.

Metal organic framework materials(MOFs) are coordination polymers formed by coordination. Recent studies have found that MOFs are the kind of heterogeneous catalysts with excellent catalytic performance due to their stable active sites in many reactions. In this paper,the ZnCo-MOF bimetallic catalyst material were prepared by the synthetic method of rotational hydrothermal crystallization using ZnO as the zinc source. X-ray diffraction(XRD), Fourier transform infrared spectrum(FTIR),scanning electron microscopy(SEM)and X-ray photoelectron spectro- scopy(XPS)were used to represent the morphology,structure and composition of the catalyst. The prepared catalyst can obtain epoxide with high conversion and high selectivity without adding any initiator or co-reducing agent in the air epoxidation reaction of catalyzed diolefin by microwave heating. The ZnCo-MOF catalyst synthesized by rotational hydrothermal method(110 r/min)has the best activity in the catalytic epoxidation of alpha-pinene and alpha-methylstyrene, which can obtain 86.3% and 99.8%(molar fraction)conversion,respectively,and the selectivity of the correspon- ding epoxides reach 93.8% and 94.3%.

The epoxy compounds are useful intermediates and precursors in the production of fine chemicals and drugs. In the epoxidation reaction system, Co-MOF, a kind of cobalt-based heterogeneous catalytic material, has been widely studied for its simple synthesis, stable structure and excellent ability of molecular oxygen activation. For the first time, we used potassium persulfate as the initiator for the efficient air epoxidation reaction catalyzed by Co-MOF materials, which had better catalytic effects than aldehydes or peroxy compounds. As a new initiator, potassium persulfate reduces the reaction temperature and increased the amount of substrate olefins. In addition, potassium persulfate reduced the activation energy of the reaction, so that the ratio of olefin to initiator was further reduced, showing a better efficiency than initiators of aldehydes or peroxy compounds. Moreover, the application of potassium persulfate to the epoxidation reaction of other catalysts has also achieved good results.