Sodium Alginate Intercalated Zinc-Containing Layered Double Hydroxides for the Catalytic α-Pinene Oxidation

Abstract

In this paper, the sodium alginate (SA) intercalated into a series of binary Mg-Al、Cu-Al, Zn-Al flaky layered double hydroxides (FLDH/SA) were fleetly prepared by the technology of the microwave-crystallization and low saturated state of coprecipitation. The purposed sample was characterized by XRD, IR and SEM. The result shows that the sample synthesized Zn-FLDH/SA with the flexible slice has the structure of LDHs, indicating the preparations are successful under microwave irradiation. The three types of CFLDH/SA were the calcined products of the three FLDH/SA under 673K for 4h, which were then applied to the catalytic α-pinene oxidation using 30 wt% hydrogen peroxide as oxidant. The effects of reaction time, catalyst type, reaction medium and so on were also investigated in details. The results show the Zn-CFLDH/SA is the best catalyst, α-pinene conversion and the selectivity of α-pinene epoxide , verbenol, verbenone can reach 69.6% and 29.1%, 39.6%, 12.0%, respectively, under optimized reaction conditions of acetone: water = 1:1 as reaction solvent, catalyst concentration of 0.431 g/L, reaction temperature 60 oC and reaction time 3 hours, Zn-CFLDH/SA as catalyst.