SYNTHESIS OF FUNCTIONAL UNSATURATED POLYESTER BY USING RARE EARTH CATALYSTS 2.TERPOLYMERIZATION OF EPICHLOROHYDRINMALEIC ANHYDRIDE-CARBON DIOXIDE WITH Y(P_(204))_3-Al(i-Bu)_3

Teroolymerization of enichlorohydrin（ECH）-maleic anhydride（MAn）-carbon dioxide（CO;） was carried out by using Y(P;);-Al（i-Bu）;as catalyst for the first time.The terpolymersobtained were characterized by IR and;H-NMR.It was foundthat the composition of the teroolymer was influenced by theaddition mode,initial monomer charge ratio,etc.

Synthesis of PET and Its Copolymer with Rare Earth Catalysts

A new catalyst system was used in the synthesis of polyethylene terephthalate(PET) and its copolymers, which involved a Ln 3+ containing compound. The catalytic effects were studied, and it was found that the direct esterification reaction of terephthalate acid(TPA) with ethylene glycol(EG) can be accelerated by the addition of Ln 3+ containing compound, which acts as a promoter of the catalyst Sb 2O 3 in polycondensation of bis hydroxyethyl terephthalate(BHET).

Synthesis of Polyester and Copolyester Catalyzed byRare Earth Compounds

The catalytic effectsof Ln3+ on synthesis of polyethyleneterephthalate and its copolyesterswere studied. The direct esterification reaction of terephthalate acidwith ethylene glycol can be accelerated hy addition of Ln3+, and theLn3+, compound can be acted aspromoter of Sb2O3 in the stage ofpolycondensation. The mechanismof esterification and polycondensation by addition of Ln3+ was discussed. The thermal-stabilities ofpolyethylene terephthalate and itscopolyesters obtained by addihon ofLn3+ were also investigaed.

Effect of yttrium and manganese addition on catalytic soot combustion activity and anti-high-temperature stability of CeO_(2) catalyst

In order to analyze the influence of the addition of yttrium and manganese on the soot combustion performance and high temperature stability of CeO_(2) catalyst,a series of Y/Mn-modified CeO_(2) catalysts were prepared.The effects of structural properties,textural properties,oxygen vacancies,Ce^(3+),surface adsorbed oxygen species,reduction properties and desorption properties of oxygen species on the activity were analyzed by various characterization methods.The results of the activity test show that the addition of manganese is beneficial to enhancement of the activity,while the addition of yttrium increases the amount of reactive oxygen species,but decreases the activity.After aging at 700℃,the activity of the CeMn catalyst decreases most sharply,while the catalytic activity of the CeY catalyst can be maintained to a certain extent.Interestingly,the addition of yttrium and manganese at the same time can stabilize the activity.The fundamental reason is that yttrium and manganese move to the surface of the solid solution after aging,which increases the reduction performance of the catalyst,thus contributing to the increase of activity.Although the activity of CeYMn catalyst decreases after aging at 800℃,it is still higher than that of other catalysts aged at 700℃.

A review of C_1 chemistry synthesis using yttrium-stabilized zirconia catalyst

C1 chemistry based on synthesis gas, methane, and carbon dioxide offers many routes to industrial chemicals. The reactions related to the synthesis of gas can be classified into direct and indirect approach for making such products, such as acetic acid, dimethyl ether, and alcohol. Catalytic syngas processing is currently done at high temperatures and pressures, conditions that could be unfavorable for the life of the catalyst. Another issue of C1 chemistry is related to the methane-initiated process. It has been known that direct methane conversions are still suffering from low yields and selectivity of products resulting in unprofitable ways to produce products, such as higher hydrocarbons, methanol, and so on. However, many experts and researchers are still trying to find the best method to overcome these barriers, for example, by finding the best catalyst to reduce the high-energy barrier of the reactions and conduct only selective catalyst-surface reactions. The appli- cation of Yttria-Stabilized Zirconia （YSZ） and its combination with other metals for catalyzing purposes are increasing. The existence of an interesting site that acts as oxygen store could be the main reason for it. Moreover, formation of intermediate species on the surface of YSZ also contributes significantly in increasing the production of some specific products. Understanding the phenomena happening inside could be necessary. In this article, the use of YSZ for some C1 chemistry reactions was discussed and reviewed.

Effect of intermediate layer on the activity and adhesion stability of metal monolith supported LaMn-hexaaluminate catalyst for methane combustion

Al2O3 and La2O3 layers were coated respectively on a FeCrAl alloy foil by a dip-coating technique and used as the second support for the active LaMnAl11O19 hexaaluminate （HA） phase in a metallic monolithic catalyst. A sample without an intermediate layer was employed for comparison. The properties and performances of the catalyst were examined with X-ray diffraction （XRD）, scanning electron microscopy （SEM）, ultrasonic vibration and thermal shock techniques. Methane catalytic combustion was performed to evaluate the activity of the catalyst. The results showed that the activity and adhesion of the HA to the alloy foil could be improved with the introduction of the intermediate layer. Al2O3 provided a strong adhesion, while La2O3 weakened the interaction between the active component and alloy foil. For the activity, the catalysts made with the two different intermediate materials also showed difference.

Possible negative influences of increasing content of cerium on activity and hydrothermal stability of Rh/ceria-zirconia three-way catalysts

The activity and hydrothermal stability of the Rh/Ce_(x)Zr_(1-x)O_(2)(x=0,0.05,0.3,0.5) model three-way catalysts for gasoline vehicle emissions control were investigated in this work.Among the Rh/Ce_(x)Zr_(1-x)O_(2) samples with different Ce/Zr ratios,the Rh/ZrO_(2) sample exhibits a significantly better activity and hydrothermal stability than the rest of the samples.The impacts of having more Ce components in the Rh/Ce_(x)Zr_(1-x)O_(2) catalysts are associated with the strong Rh-O-Ce interaction that tends to over stabilize the rhodium species.A significant amount of such rhodium atoms can be found in the bulk of the support oxides after a hydrothermal aging at 1050℃ with 10% H_(2)O in air for 12 h.Differently,the sintering of rhodium on the surface of Rh/ZrO_(2) catalysts is the main reason for the catalyst deactivation during the hydrothermal aging.These findings provide an example where high dispersion of supported metal induced by strong metal-support interactions does not necessarily lead to high catalytic activity.

Unraveling the nature of cerium on stabilizing Cu/SAPO-34 NH_(3)-SCR catalysts under hydrothermal aging at low temperatures

To reveal how cerium stabilizes Cu/SAPO-34 at low-temperature hydrothermal aging,various amounts of cerium were introduced into Cu/SAPO-34 via impregnation method and treated at 70℃with RH 80%for 96 h.Cerium as Ce^(3+)and CeO_(2)nanoparticle is located on the surface of Cu/SAPO-34,and Ce^(3+)plays a vital role on gradually decreasing surface acidity and blocking defect sites with an increase of Ce loading.After hydrothermal aging,Cu/SAPO-34 with high Ce loading shows the superior SCR activity comparable to fresh samples.It is proven that the surface acidity determines the stability of the structure during hydrothermal aging process,and lower surface acidity prevents the number of Cu(Ⅱ)ions from decreasing significantly.Furthermore,the structure's stability helps the recovery of Cu(Ⅱ)ions and renders an outstanding regene ration ability.Our finding paves the way for the design of new Cu/SAPO-34catalysts with good SCR activity and long-term stability in real application.

Effect of doping rare earth oxide on performance of copper-manganese catalysts for water-gas shift reaction

Rare earth-doped copper-manganese mixed oxide catalysts were prepared by coprecipitation and mechanical mixing using copper sulfate, manganese sulfate, and rare-earth oxides REO （REO indicates La2O3, CeO2, Y2O3, or Pr6O11） as raw materials. The samples were characterized by X-ray diffraction （XRD）, temperature-programmed reduction （TPR）, temperature-programmed reduc-tion of oxidized surfaces （s-TPR）, and temperature-programmed desorption （TPD）. Catalytic activities were tested for a water-gas shift reaction. Doping rare earth oxides did not alter the crystal structure of the original copper-manganese mixed oxides but changed the interplanar spacing, adsorption performance and reaction performance. Doping with La2O3 enhanced the activity and stability of Cu-Mn mixed oxides because of high copper distribution and fine reduction. Doping with CeO2 and Y2O3 also decreased the reduc-tion temperatures of the samples to different degrees while improving the dispersion of Cu on the surface, thus, catalytic activity was better than that of undoped Cu-Mn sample. The Pr6O11-doped sample was difficult to reduce, the dispersion of surface coppers was lowered, resulting in poor activity.

Activity and deactivation behavior of Au/LaMnO_3 catalysts for CO oxidation

Perovskite oxide LaMnO3 was prepared by sol-gel method and the nanosize Au/LaMnO3 catalyst was prepared by deposition-precipitation（DP） method in the paper.Characterization of the catalyst sample was made by X-ray diffractometer（XRD）,atom absorption spectra（AAS） and X-ray photoelectron spectroscopy（XPS） instrumental methods.The activity,long-term stability and the reasons for deactivation of the gold catalyst in CO oxidation were investigated.The experiment results demonstrated that the Au/LaMnO3 catalyst exhibited high stability in the ambient storage process.However,the gradual decrease in initial activity during 100 h reaction was still observed,which could be ascribed to the aggregation of gold particles and the transfer from gold ion to the metal gold.

Effect of calcination process on performance of 3DOM CeMnO3 catalysts

A series of 3DOM CeMnO3 perovskite catalysts were prepared by poly(methyl methacrylate)hardtemplating-excessive impregnation method at calcination temperature of x℃(x=600,700,800)and the heating rate of y℃/min(y=1,2,5,10).The samples were characterized by Brunauer-Emmett-Teller method,scanning electron microscopy,transmission electron microscopy,H2-temperature programmed reduction,X-ray photoelectron spectroscopy,X-ray diffraction,moreover,the effect of the calcination process on the catalytic activity of the samples were discussed by the catalytic combustion of toluene.The results show that the 3DOM CeMnO3 catalysts calcined at 600℃promote the formation of a perovskite structure,inhibit the reduction of the Mn4+species in the catalyst with high temperature.The catalyst expresses the complete macroporous structure,large specific surface area(38.8 m^(2)/g),higher adsorption oxygen concentration and Mn4+substance concentration,with a low T90%=172℃.By preparing the catalysts at different calcination heating rates,it can be concluded that the catalyst possesses a high concentration of adsorbed oxygen and a low reduction temperature and a large specific surface area(40.42 m^(2)/g)greatly promotes adsorption stage catalytic oxidation reaction and catalytic combustion of toluene at low temperature under the heating rate of 5℃/min.When the heating rate is 1℃/min,the catalyst has a complete macroporous structure(>250 nm),which is beneficial to the exchange of macromolecular substances during the catalytic reaction and the catalyst has a high concentration of lattice oxygen suitable for the catalysis of toluene in high temperature flue gas combustion.

CO and C_3H_8 total oxidation over Pd/La-Al_2O_3 catalysts: Effect of calcination temperature and hydrothermal treatment

A series of Pd/La-Al2O3（PLA） catalysts with La-Al2O3（LA） support calcined at different temperatures（500, 700, 900 and 1050 oC） were prepared using an incipient wetness impregnation method. The activity of the fresh and hydrothermally aged PLA catalysts were tested for total oxidation of CO and C3H8. The activity of the fresh PLA catalysts for CO and C3H8 oxidation increased with increasing calcination temperature of the support, while the activities of the aged catalysts declined and became essentially the same. CO chemisorption results revealed that the suppressed activities of the aged catalysts were mainly due to the decline of palladium dispersion. The turnover frequency（TOF） of CO oxidation increased with increasing reduction ability of the catalysts, with a fresh catalyst calcined at 1050 oC having the highest value（0.048 s–1）. However, the TOF of C3H8 total oxidation was affected by not only the redox properties of catalysts but also the size of Pd particle, and large Pd particles possessed higher TOF value of C3H8 oxidation, with the highest value（0.125 s–1） being obtained on an aged catalyst calcined at 500 oC.

A rationale for the development of thermally stable nanostructured CeO_2-ZrO_2-containing mixed oxides

CeO2-ZeO2 solid solutions are extensively used as oxygen storage promoters in the current automotive three-way catalysts. High thermal stability of the textural properties is one of the most important requirements for practical application since temperatures up to 1273 K are easily experienced by these materials under real working conditions. In the present paper, we investigated how hydrothermal treatments applied to cakes of doped and undoped ZrO2-rich CeO2-ZrO2 precursors might improve the thermal stability of the final CeO2-ZrO2 solid solution. A rationale was developed that allowed to correlate the morphology of the hydrothermaUy treated cake with the thermal stability at 1273 K of the final product, which did not depend on the composition of the mixed oxides.

PVC塑料稀土复合热稳定剂的研制

本文制备了柠檬酸稀土、月桂酸稀土、硬脂酸稀土和苹果酸稀土 ,对各稀土产品进行了热稳定性研究 ,发现苹果酸稀土的热稳定性最好 ,其长期热稳定性与有机锡相当。并用苹果酸稀土与硬脂酸锌进行复配 。

含芳香组分共聚酯的生物降解性研究

采用稀土-钛催化剂,以1,4-丁二醇、己二酸和对苯二甲酸二甲酯为原料制备了聚己二酸丁二醇酯和对苯二甲酸丁二醇酯(BT)的一系列共聚酯,对共聚酯的相对分子质量、熔点、断裂拉伸强度和断裂伸长率进行了测试。并采用堆肥埋片法,将BT 摩尔分数为40％和60％的两种共聚酯与纸、聚乙烯、环保餐盒薄膜进行了生物降解性对比实验;以失重率、降解速率和相对分子质量变化作为指标,考察了共聚酯的生物降解性,并简述了生物降解行为的作用方式。实验结果表明,通过在聚己二酸丁二醇酯中引入摩尔分数为40％-60％的BT,所制备的共聚酯既具有一定的力学性能,又具有一定的生物降解性;且随BT含量的增加, 共聚酯的生物降解性变差。

碱式羧酸稀土热稳定剂及其协同效应的研究

制备了碱式双月桂酸稀土、碱式单月桂酸稀土、碱式单硬脂酸稀土和环烷酸稀土 ,对各稀土产品进行了热稳定性研究 ,发现碱式双月桂酸稀土的热稳定性最好 ,其长期热稳定性与有机锡接近。用碱式双月桂酸稀土与硬脂酸锌进行复配 。

等离子喷涂氧化铝涂层的结构与性能研究

采用等离子喷涂技术 ,在 Fe Cr Al RE合金基体表面制备铝钛涂层和氧化铝涂层 ,与浸渍法制备的氧化铝涂层进行比较。利用 XRD、SEM、BET和超声振动等分析测试技术 ,对涂层的微观结构与表面特性进行研究。结果表明 ,加入适量的 Ce O2 、L a2 O3 、Zr O2 、Si O2 后 ,氧化铝喷涂涂层的表面组成相主要保持为 γ- Al2 O3 ,其蜂窝状多孔结构上堆积了大量弥散分布的纳米微粒 ;这种复合结构既保证了涂层与载体牢固的结合 ,表现出优于氧化铝浸渍涂层的抗振性与抗热震性 ,又使得涂层的几何比表面达到 32 .1m2 / g,大大超过铝钛喷涂涂层。因此 ,可用等离子喷涂工艺制备氧化铝涂层 ,作为承载活性组分的分散层 。

聚氯乙烯加工用稀土助剂研究进展

稀土在聚氯乙烯 (PVC)助剂上显示出了优良的性能 ,本文综述了PVC用稀土助剂 ,特别是稀土热稳定剂的开发、研究进展以及发展前景 ,并讨论了稀土热稳定剂的作用机制。确定稀土化合物是一种可以替代传统稳定剂的新型稳定剂 ,具有广阔的应用前景。

聚氯乙烯塑料稀土稳定剂的研究开发现状和发展趋势

热稳定剂是聚氯乙烯塑料(PVC)加工中的重要助剂,目前世界各国仍以传统的重金属类热稳定剂为主。未来热稳定剂行业的主要发展趋势是高效、低毒、复合型、无污染,重金属类稳定剂将逐渐被新型环保热稳定剂淘汰。稀土稳定剂作为我国独有的一类热稳定剂,具有热稳定性好、无毒、无污染等许多优点,同时我国具有丰富的稀土资源,因此大力发展稀土热稳定剂是我国热稳定剂行业发展的主要方向。

稀土基汽车尾气催化剂的研究 Ⅱ:稀土助剂对催化活性的影响

利用浸渍法制备含Ce-La稀土助剂改性的Pt-Rh三效催化剂,采用多种表征手段和高温抗硫水热老化实验,考察Ce-La稀土对Al2O3载体的热稳定性和催化剂活性的影响。结果表明:稀土La2O3的添加主要改善载体Al2O3的高温高比表面性能;CeO2的引入明显提高了CO和NO的催化转化活性,但对HC的转化几乎无影响;CeO2的添加也促进了催化剂的抗硫水热老化性能,并显著拓宽催化剂的三效窗口。主要归因于CeO2的添加促进了催化剂上CO、HC和NO间的相互作用以及CeO2所特有的储氧功能。