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Preparation and reaction mechanism of novel Ce_(x)Co_(y)Cuz oxide composite catalysts towards oxidation of o-xylene

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Journal of Rare Earths 2022年第10期40卷 1573-1583页

作者： Mengge Zhao Weijian Cai Jiwu Li School of Environmental Science and Engineering Zhejiang Gongshang UniversityHangzhou 310018China Department of Chemistry School of Food Science and BiotechnologyZhejiang Gongshang UniversityHangzhou 310018China

Ce_(x)Co_(y)Cuzoxide composite catalysts were prepared by using polyethylene glycol, citrate sol-gel method combined with PMMA template for the oxidation of o-xylene. The catalysts were characterized by the Xray diffraction(XRD), H2-temperature programmed reduction(H2-TPR), X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared spectroscopy(FT-IR), etc. The catalytic activity for o-xylene was investigated. The catalytic degradation pathway and mechanism of o-xylene were inferred. The results show that Ce o_(2)is mainly present on the surface of all catalysts. The surface area of Ce_(2)Co1Cu1is up to 77.2 m^(2)/g, and the average pore size is 10.62 nm. It exhibits redox and sufficient Ce^(4+)and Ce^(^(3+)), and reactive oxygen species, and has maximum o-H and C=o in the five catalyst samples. The catalytic activity of Ce2Co1Cu1is the best at low temperature, with the T50and T90values of 235 and 258°C at a space velocity of 32000 h-1, respectively. The o-xylene is oxidized to o-methyl benzaldehyde, and then further oxidized to o-methylbenzoic acid, and finally Co_(2)and H2o are formed.

关键词： Ce_(x)Co_(y)Cuz composite oxide catalyst Polyethylene glycol Citrate sol-gel method Catalytic activity o-xylene Rare earths

Effect of pretreatment on Pd/Al_2o_3catalyst for catalytic oxidation of o-xylene at low temperature

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Journal of Environmental Sciences 2013年第6期25卷 1206-1212页

作者： Shaoyong Huang Changbin Zhang Hong He Research Center for Eco-Environmental Sciences Chinese Academy of Sciences

The effect of pretreatment on Pd/Al2o3 catalysts for the catalytic oxidation of o-xylene at low temperature was studied by changing the pretreatment and testing conditions. The fresh and pretreated Pd/Al2o3 catalysts were characterized by transmission electron microscopy （TEM）, X-ray photoelectron spectroscopy （XPS） and X-ray diffraction （XRD）. The results showed that the pretreatment dramatically changed the Pd/Pdo ratio and then significantly affected the Pd/Al2o3 activity; while the pretreatment had not much influence on Pd particle size. The Pd/Al2o3 pre-reduced at 300~C/400~C, which has fully reduced Pd species, showed the highest activity; while the fresh Pd/Al2o3, which has fully oxidized Pd species, presented the worst performance, indicating the Pd chemical state plays an important role in the catalytic activity for the o-xylene oxidation. It is concluded that metallic Pd is the active species on the Pd/Al2o3 catalyst for the catalytic oxidation of o-xylene at low temperature.

关键词： Pd/Al2o3 o-xylene catalytic oxidation noble metal VoC

Complete catalytic oxidation of o-xylene over Ceo_2 nanocubes

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Journal of Environmental Sciences 2011年第1期23卷 160-165页

作者： Lian He Yunbo Yu Changbin Zhang Hong He State Key. Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

The activities of Ceo2 nanocubes calcined at different temperatures were tested for catalytic oxidation of o-xylene. Using Ceo2 nanocubes as catalysts, complete catalytic oxidation of o-xylene was achieved below 210℃. The Ceo2 nanomaterials were characterized by means of BET, X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and high-resolution transmission electron microscopy （HRTEM）. From the TEM images, all Ceo2 nanocubes displayed cubic morphology irrespective of calcination temperature. The HRTEM images revealed that these nanocubes were enclosed by reactive {001} planes, which may contribute to the intrinsically catalytic property of o-xylene oxidation. The higher activity of Ceo2 nanocubes calcined at 550℃ than those calcined at above 550℃ was attributed to their smaller crystallite size and larger surface area. The influences of reaction conditions were also studied, which found that a higher reaction temperature was necessary for complete catalytic oxidation of o-xylene at higher weight hourly space velocity （WHSV） and o-xylene concentration.

关键词： Ceo2 nanocubes o-xylene catalytic oxidation calcination temperature

对、邻二甲苯和醋酸二元液体混合物在不同温度和压力下的密度和超额摩尔体积(英文)

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Chinese Journal of Chemical Engineering 2008年第2期16卷 247-255页

作者：杨天宇夏淑倩邸志国马沛生 School of Chemical Engineering and Technology Tianjin University China Tianjin 300072

A new apparatus was designed with a thick-walled glass capillary,electric heater tube with red copper and heat preservation.The thick-walled glass capillary was used for its advantages of resistance to acid corrosion and pressure,and ease of observation.The experimental densities over the entire range of mole fraction for the bi- nary mixture of p-xylene+acetic acid and o-xylene+acetic acid were measured using the new apparatus at tempera- tures ranging from 313.15K to 473.15K and pressure ranging from 0.20 to 2.0 MPa.The density values were used in the determination of excess molar volumes,VE.The Redlich-Kister equation was used to fit the excess molar volume values,and the coefficients and estimate of the standard error values were presented.The experimental re- sults prove that the density measurement apparatus is successful.

关键词： density excess molar volume p-xylene o-xylene acetic acid

Adsorption-Desorption of BTX (Benzene, Toluene and o-xylene) on Fe, Fe-Al Pillared Clay

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Journal of Encapsulation and Adsorption Sciences 2017年第1期7卷 40-66页

作者： Zohra Mècabih Laboratory of Materials and Catalysis Department of ChemistryFaculty of Exact SciencesUniversity of Djillali LiabesSidi Bel AbbesAlgeria

The studies are conducted in laboratory to determine the adsorption-desorption behavior of BTX (benzene, toluene and o-xylene) in gas phase on Fe, Fe-Al pillared clays adsorbents. In experimental conditions of constant atmospheric pressure, initial concentrations with an increasing volume (0.5 - 2 ml) injected benzene (2.25), toluene (1.89) and o-xylene (1.66) μmol/L at T (40℃, 60℃ and 80℃), and the adsorption increases with increase of temperature, indicating that the adsorption process would be a chemical adsorption rather than physical one. The results are shown that the BTX adsorption data fitted very well (R2 > 0.999) to the both equations Langmuire and Elovitch for the three samples: bentonite (B), Fe-bentonite () and Fe-Al/bentonite (). At 80℃, the BTX adsorption capacity increased in the following order: . The maximum adsorption capacity () at 80℃ is 175.13, 171.84 and 171.81 μg/g respectively for benzene, toluene and o-xylene for;the last is a good adsorbent of BTX removal. The benzene diffuses faster than toluene and o-xylene. Thermodynamic parameters, such as ,and are also discussed and the results suggested that the BTX adsorption on all samples used is a spontaneous and endothermic process. Desorption studies show that BTX is very easily desorbed with .

关键词： Fe Al-Pillared Benzene Toluene o-xylene Adsorption

Investigation of Mechanisms About Effects of Promoters P_2o_5,K_2o and A1_2o_3 on oxidation of o-xylene to Phthalic Anhydride

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Chemical Research in Chinese Universities 1990年第2期6卷 141-148页

作者： Zheng Xiaoming, He Weilian, Yuan Xianxin, Zhou Lichua and Jin Songshou (Department of Chemistry, Hangzhau University, Hangzhau)

We succeeded in designing an effective catalyst, V2o5-P2o5-K2o/Al2o3. Sio2, by which a high yield of PA,105wt% can be gained in middle-sized industrial fluidized bed apparatus without addition of any promoting gas.The mechanisms of effects of P2o5, K2o and Al2o3 on the surface properties of V2o5 were investigated by means of TPD and XRD. And the selectivity of oxidation are explained.Addition of a great deal of P2o5 restrains the activity of donating surface oxygen from V2o5, but increases the number of sites which donate surface oxygen. Addition of K2o promotes donation of surface oxygen from V2o6, and decreases the number of sites of donating oxygen, on the other hand, addition of K|o makes the surface structure of V2o5 catalysts more stable. Coating a small amount of Al2o2 onto support, Sio2, restrains the activity of donating oxygen and increases the number of sites of donating surface oxygen from V2o5.

关键词： Catalyst oxidation Phthalic anhydride o-xylene