Papers by Author: Zhen Dong Zhao

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Authors: Peng Wang, Zhen Dong Zhao, Li Zhi He, Liang Wu Bi, Yu Xiang Chen
Abstract: Mesoporous zirconias were prepared by precipitation method using rosin-based quaternary ammonium salt as a directing agent. The samples were characterized by means of XRD, FT-IR and N2-adsorption and desorption measurements. The phase of precursors was amorphous, and well crystallized tetragonal zirconias were obtained after the calcination at 450 °C. The synthesized mesoporous zirconias possessed high surface areas ranging from 183.56 to 203.87 m2g-1 and big pore diameters varying from 6.27 to 7.58 nm. The content of the rosin-based quaternary ammonium salt had significant influence on the textural properties of the mesoporous zirconias. Surface areas, pore volumes and pore diameters of the mesoporous zirconias decreased when increasing the surfactant dosage.
Authors: Lu Lu Han, Liang Wu Bi, Zhen Dong Zhao, Ya Li Xing
Abstract: Squalene, a natural antioxidant, was microencapsulated by the method of ultrasonic spraying and freeze-drying using shell materials of gelatin and arabic gum. The suitable condition for ultrasonic emulsification before ultrasonic spraying and freeze-drying was frequency 28 kHz and running time 20 min. The reasonable condition for microencapsulation of squalene by ultrasonic spraying and freeze-drying was gelatin 3.0 %, arabic gum 5.0 %, maltodextrin 6.0 % and sucrose ester 0.9 %. The appearance and size of microcapsules of squalene were measured by scanning electron microscope and metallographic microscope. The microcapsules of squalene were smonth spheres at the diameter of about 10 μm.
Authors: Ya Li Xing, Liang Wu Bi, Zhen Dong Zhao, Tian Juan Xia
Abstract: A quick and accurate HPLC method has been developed for the simultaneous quantification of two bioactive triterpenes, ursolic acid and oleanolic acid in Paulownia leaves. The samples were analyzed on a Shim-pack ODS-CLC (M) (4.6 mm × 250 mm, 5 μm) column kept at 21 °C, using the methanol and aqueous phase containing 0.05%phosphoric acid with the volumetric ratio of 91.7:8.3 as the mobile phase at a flow rate of 0.6 mL/ min, and the detection wavelength was set at 210 nm. The method was validated and applied to the simultaneous quantification of the two triterpenes in Paulownia leaf extract. The standard curves were established in the range of 0.44 ~ 8.75 μg for oleanolic acid and 0.92 ~ 18.37 μg for ursolic acid. The contents of oleanolic acid and ursolic acid in leaves of Paulownia were determinated using the HPLC method and the contents were 3.87 mg/g and 13.61 mg/g, respectively.
Authors: Yan Gu, Yu Xiang Chen, Zhen Dong Zhao, Chang Tai Guo, Dong Mei Li, Liang Wu Bi
Abstract: The color-lightening of rosin was achieved to give light-colored and qualified rosin that was improved at the optimal conditions for 4 Gardner color grades, while rosin was treated at 180 ~ 270 °C for 1 ~ 4 h in inert gases. The color of rosin was deepened slightly at the initial, and then gradual lightened with the increase of treating temperature. The best color-lightening effect was observed from Pinus massoniana rosin. The acid number and softening point of rosin tended to decrease both accompanying with the color-lightening. According to a general consideration on main requirements such as color, acid number, softening point and the others, the suitable treating conditions for rosin color-lightening were suggested to be as temperature 240 ~ 260 °C and time 1 ~ 3 h.
Authors: Liang Wu Bi, Qiu Ge Zhang, Peng Wang, Zhen Dong Zhao, Da Wei Li, Yu Xiang Chen, Dong Mei Li, Yan Gu, Jing Wang, Xian Zhang Liu
Abstract: Turpentine-based dipentene (TBDP) contains limonene 30.32 %, terpinolene 31.35 %, α-terpinene 7.55 %, γ-terpinene 6.40 % and p-cymene 12.87 %. Three Pd/C catalysts were characterized by BET, XRD, TG-DTG and atomic absorption spectrometry (AAS). The properties of the catalysts on TBDP conversion were compared. Difference of catalytic competitive reactions of TBDP by catalyst A with the change of reaction temperature was discussed in detail. The yield of p-cymene at 280-310°C was over 95.0 %. It was important to control the reaction temperature for TBDP dehydrogenation catalyzed by Pd/C catalysts. It is valuable to probe the catalytic behaviors of Pd/C catalyst on TBDP dehydrogenation for research and development of efficient preparation technology of p-cymene from TBDP.
Authors: Yan Gu, Zhen Dong Zhao, Jie Song, Dong Mei Li, Jing Wang, Yan Ju Lu, Liang Wu Bi
Abstract: There was rarely high-purity α-terpineol or pure-monomer α-terpineol in China due to difficulty in isolating α-terpineol and γ-terpineol. Aiming at the separation problem, α-terpineol was directional synthesized by one-step method in a uniform system. The influence factors of stereochemistry structure, thermodynamic analysis and stability of reactants, products and carbocations were researched, conducting the experiments in optimal reaction conditions. All the influence factors about generating trend of objective product α-terpineol and byproduct γ-terpineol were discussed and the reaction mechanism was studied. This paper provided certain theoretical basis on prepare high-purity α-terpineol.
Authors: Yu Xiang Chen, Zhen Dong Zhao, Yan Gu, Yan Ju Lu
Abstract: The thermal isomerization reaction of isopimaric acid was studied by a treatment at different temperature of 250 °C, 260 °C and 270 °C for 1-5 h under the protection of nitrogen. The isomerization mechanism of isopimaric acid was illuminated. Isopimaric acid was remarkably isomerized to 8, 15-isopimaric acid and sandaracopimaric acid, the higher thermal treatment temperature combined with longer thermal treatment time, the faster isomerization rate of isopimaric acid was observed. It was found that the isomerization rate of isopimaric acid towards 8, 15-isopimaric acid was faster than to sandaracopimaric acid. The decomposition reaction of pimaric-type acids occurred slightly in conditions of 250 ~ 270 °C.
Authors: Da Wei Li, Liang Wu Bi, Zhen Dong Zhao, Dong Mei Li, Yan Gu, Jing Wang, Xian Zhang Liu
Abstract: The variation regulation of five bioactive components including carnosic acid (CA), carnosol (CO), rosmarinic acid (RA), oleanolic acid (OA) and ursolic acid (UA) in rosemary leaves and extraction procedure was studied. The effects of rosemary sources, steam distillation time, activated carbon dosage and storage time of extraction solution on variation regulation of bioactive components were discussed in detail.
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