Catalytic Decomposition of CFC-12 over Solid Super Acid Mo2O3/ZrO2

Catalytic decomposition of dichlorodifluoromethane (CFC-12) in the presence of water vapor and oxygen was studied over a series of solid super acids Mo2O3/ZrO2 that had different ZrO2 content by using a fixed-bed reactor. CO2 and CClF3 were the main products and no CO was detected as by-product. The decomposition activity of solid super acid largely depended on the content of ZrO2 and the calcination temperatures of Mo2O3/ZrO2. The optimal calcination temperature and content of ZrO2 for preparing Mo2O3/ZrO2 with the highest activity for catalytic decomposition of CFC-12 were 450°C and 20–40 wt?%, respectively. Adopting a low concentration of oxygen and CFC-12 together with a high concentration of water vapor was preferable for having the high conversion efficiency of CFC-12 and the selectivity for CO2. The catalytic activity of Mo2O3/ZrO2 remained steady for 100 h in continuous operation.     

稀土复合固体超强酸SO42-/ZrO2-2%Gd2O3催化合成乙酸戊酯

制备了稀土复合固体超强酸SO4^2-／ZrO2-2％Gd2O3催化剂，并对以乙酸和戊醇为原料合成乙酸戊酯的反应条件进行了研究。研究表明：当戊醇与乙酸的摩尔比为1：1．5，反应时间为6h，反应温度为130℃，催化剂用量为6％戊醇的质量时，反应酯化率最高，酯化率可达98．93％，选择性高达100％。研究发现，该催化剂可重复使用，并能活化再生。     

SO42-/TiO2-La2O3催化剂催化合成苹果酯-B

制备了稀土改性固体超强酸SO42-/TiO2-La2O3催化剂。以SO42-/TiO2-La2O3为多相催化剂,对以乙酰乙酸乙酯和1,2-丙二醇为原料合成苹果酯-B的反应条件进行了研究。实验表明:固体超强酸SO42-/TiO2-La2O3是合成苹果酯-B的良好催化剂,最佳反应条件为:n(乙酰乙酸乙酯)∶n(1,2-丙二醇)=1∶1.5,催化剂用量为反应物料总质量的1.5%,环己烷为带水剂,反应时间1.5h,反应温度85℃～110℃。在上述条件下,苹果酯-B的收率可达88.6%。     

铈改性固体超强酸SO2-4/Sb2O3的制备及催化性能研究

以SbCl3为原料经醇化水解制 Sb2O3前体氧化物,通过浸渍一定量的(NH4)2SO4和掺杂Ce4+制备了一种新型催化剂SO42-/ Sb2O3/Ce4+ .以催化合成乙酸苄酯为探针反应,考察了(NH4)2SO4的浓度、Ce(NO3)4 的浓度、焙烧温度等因素对其催化性能的影响,并采用IR、TG/DTA、Hammett法等对其进行表征.结果表明,1.5 mol·L-1的(NH4)2SO4和含Ce(NO3)4 2.8%的混合液浸渍锑前体氧化物,经110℃烘干后,于350℃焙烧2 h所得的催化剂活性最好,其酯化率达到97%..     

SO4（2-）/ZrO2固体超强酸的制备及表征

对传统沉淀-浸渍法制备SO42-/ZrO2（SZ）工艺进行了改进,探索用一步法制备SZ。分别以氯氧化锆（添加硫酸铵引入SO42-）和硫酸锆为锆源,以氨水为沉淀剂,经水解、水热、洗涤、干燥、焙烧制得高比表面积的SO42-/ZrO2。利用XRD、SEM、FT-IR、低温氮气吸附-脱附、Hamm ett指示剂法等进行结构及酸性的表征,研究了锆盐原料浓度、水解pH值、焙烧温度对SO42-/ZrO2性能影响。研究表明：水解pH值对SZ的比表面积影响最大;焙烧温度是制备SO42-/ZrO2固体超强酸的关键,当焙烧温度达到700℃时,负载SO42-的ZrO2才由无定形向单斜相和四方相转变,制得的SO42-/ZrO2显示出强酸性。     

稀土复合固体超强酸SO42-/ZrO2-2%Sm2O3催化合成乙酸辛酯

采用共沉淀法制备了稀土复合固体超强酸SO42-/ZrO2-2%Sm2O3催化剂,并对以乙酸和辛醇为原料合成乙酸辛酯的反应条件进行了探索.研究表明,当辛醇与乙酸的摩尔比为1:2,反应时间为6h,反应温度为120℃,催化剂用量为6%辛醇的质量时,酯化率可达91.73%,选择性高达100%.研究发现,该催化剂可重复使用,并能活化再生.     

含铈固体超强酸SO2-4/ZrO2-CeO2催化合成乙酸丁酯的研究

以固体超强酸SO42-/ZrO2-CeO2作催化剂,冰醋酸和正丁醇为原料合成了乙酸丁酯.采用正交实验法对影响反应的因素进行了考察.结果表明最佳反应条件为n(醇)∶n(酸)=2∶1,催化剂用量为反应混合物总量的1.5%(质量分数),反应时间为3h,酯化率可达92.6%.     

稀土固体超强酸催化剂S2O82-/ZrO2-SiO2-Sm2O3的制备

采用沉淀-浸渍法制备了负载稀土的固体超强酸S2O82-/ZrO2-SiO2催化剂,以乙酸丁酯的合成为探针反应进行了单因素测试,考察了制备条件对催化剂性能的影响.结果表明,载入不同稀土金属氧化物、不同硅锆原子量比以及预焙烧温度、焙烧温度和浸渍液浓度等因素对催化活性有显著影响.     

稀土固体超强酸Gd3+- SO2-4/ZrO2催化合成乙酸正丁酯

采用乙酸、正丁醇为原料,以固体超强酸Gd3+ -SO2-4/ZrO2作为催化剂,催化合成乙酸正丁酯.用固体超强酸Gd3+ -SO2-4/ZrO2和SO2-4/ZrO2进行催化活性对比试验,考察浸渍硫酸浓度、浸渍时间、焙烧温度对催化剂活性的影响以及原料酸醇比、反应时间、催化剂用量对酯化率的影响,从而确定固体超强酸的最佳制备条件.试验结果表明:在反应温度105～110℃,催化剂用量1.5g,n(正丁醇)∶n(乙酸)=2.5∶1,反应时间2.5h条件下,酯化率可达98.86％;催化剂重复使用效果明显;加Gd3+的固体超强酸的催化活性明显增强.     

Decomposition of Aqueous 2,2,3,3-Tetra-Fluoro-Propanol by UV/O3 Process

2,2,3,3-Tetra-fluoro-propanol (TFP) has been extensively used in compact disk-recordable and digital versatile disk-recordable manufacture and a large amount of wastewater containing the chemical is being discharged. This investigation evaluates the feasibility and effectiveness of the use of UV, O3, and UV/O3 to degrade aqueous TFP. TFP oxidation tests were performed with initial TFP concentrations of 772–887?mg/L with various solution pH values (acidic, alkaline, uncontrolled), solution temperatures (26, 37, 48, and 60°C), and UV wavelengths (254 and 185?nm). Experimental results demonstrated that alkaline conditions favor the TFP degradation and increase the mass of TFP decomposition per unit mass of ozone consumption, in both UV254?nm/O3 and UV185?nm/O3 processes. There was no significant difference in the rate of TFP degradation when using either UV254?nm or UV185?nm. TFP exhibited zero-order degradation kinetics when sufficient ozone was supplied. A higher oxidation temperature was found to be no help for the UV/O3 oxidation of TFP in the tested concentration and temperature ranges. The cost of the UV254?nm/O3 or UV185?nm/O3 per unit volume of wastewater with an initial TFP concentration of 3,387?mg/L is comparable to that of the Fered–Fenton process as described in the literature.     

Catalytic Decomposition of Ozone Gas by a Pd Impregnated MnO2 Catalyst

A new catalyst, which was made of MnO2 impregnated with Pd for decomposition of high humidity ozone gas, was developed and its catalytic activity decrease was analyzed in a finite difference type fixed bed reactor. The activity of the catalyst was higher than that of other catalysts and an activated carbon and does not decrease so much for a long term. Therefore, its lifetime is very long. The reaction rate was shown as a first-order reaction equation for each catalyst in any operation time both under dry and wet conditions. The rate-determining step was considered to be a chemical reaction of ozone. The reaction rate constant kt decreased through two steps, fast in an early period and slowly afterward. Then, kt was analyzed as the function of operation time t and inlet concentration C0 at each humidity. From the analysis, the ozone removal performance in any size of reactor and in any time became possible to predict.     

Catalytic Incineration of Acrylonitrile with Platinum Supported on Al2O3

The catalytic decomposition of acrylonitrile with catalysts was investigated in a bench scale fixed bed reactor in this study. Two catalysts, including Pt/γ-Al2O3 and Cr2O3/α-Al2O3, were tested to study their catalytic activity in the complete oxidation of acrylonitrile. The results show that the Pt/γ-Al2O3 catalyst has better performance. The operating parameters such as operating temperature, acrylonitrile concentration, space velocity, and oxygen concentration were conducted in a series of experiments on the Pt/γ-Al2O3 catalyst. The results indicate that decomposition efficiency increases with temperature and oxygen concentration and decreases with the increases of space velocity and acrylonitrile concentration. With a regression model, the operating temperature is the most effective parameter on the decomposition of acrylonitrile. Carbon dioxide is the dominant product and carbon monoxide is an insignificant product of the decomposition of acrylonitrile. Material balance on carbon is good for the experiments. According to the BET and elemental analyzer analysis, major factors that cause the deactivation effect may result from nitrogen poisoning and carbon masking on the catalyst surface, especially at lower temperatures.     

Catalytic Behavior of CO Oxidization over Pd/ZrO2 - CeO2 Catalyst

The effects of Pd loading, cerium content, the special surface area of the support and calcination temperature on the catalytic properties of Pd-loaded zirconia-ceria mixed oxide were studied.The results show that loading Pd and increasing cerium content in the mixed oxides can enhance the catalytic activity.There is a little effect of calcination temperature on catalytic activities, implying that these catalysts are effective with good thermal stability.     

稀土固体超强酸SO42-/SnO2- Nd2O3催化合成棕榈酸甲酯

采用溶胶-凝胶法制备稀土固体超强酸催化剂SO4-/SnO2- Nd2O3,以工业棕榈酸和甲醇为原料催化合成棕榈酸甲酯.考察了氧化钕添加量、焙烧温度、硫酸浓度、醇酸质量比、催化剂用量和反应时间对酯化反应的影响.结果表明,当氧化钕添加量为5％,以2.0 mol/L硫酸浸渍后,于550℃下焙烧3h制备的催化剂性能最好.正交实验结果表明,合成棕榈酸甲酯的优化条件为:醇酸质量比为15∶25,催化剂用量为棕榈酸质量的6.0％,反应时间5h.在此条件下,酯化率为90.1％.     

Microstructure of Mullite/ZrO2 and Mullite/Al2O3/ZrO2 tough ceramic composites

The microstructural evolution in mullite/zirconia and mullite/alumina/zirconia composites after different duration heat treatments at 1570°C has been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray microanalysis. The effect of free alumina on microstructural and mechanical parameters is also reported.     

固体超强酸S_2O_8~(2-)/TiO_2-WO_3的制备及其催化性能研究

用溶胶-凝胶法制备了固体超强酸S2O82-/TiO2-WO3,并对其进行了XRD与IR表征,用乙酸乙酯合成模型反应考察了其催化性能,系统研究了WO3的含量、焙烧温度等制备条件对S2O82-/TiO2-WO3性能的影响。实验表明:在(NH4)10W12O41.xH2O质量分数为5.0%、焙烧温度为500℃条件下通过溶胶-凝胶法制备的固体超强酸S2O82-/TiO2-WO3,其载体为微细且晶格不太完整的锐钛矿型TiO2,比表面积较大,具有比浸渍法制备的SO42-/TiO2更高的硫含量和更强酸性,并具有较高的催化酯化活性和稳定性,在反应条件为:醇酸摩尔比1.48∶1、催化剂用量为冰醋酸的6.0%、反应时间2.0h,乙酸转化率可达74.1%(不加分水器)。催化剂在无需任何再生的条件下重复使用,活性下降趋势平缓,显示良好的稳定性。     

Catalytic Synthesis of Tert-Butyl Acetate by Nd2O3/Al2O3-Nd2O3/ZnO

Nd2O3 was used to support Al2O3 and ZnO to prepare a supported solid base catalyst and investigate the effect of catalyst and reaction conditions on the synthesis of tert-butyl acetate. The composited oxide of Nd2O3/Al2O3-Nd2O3/ZnO exhibited excellent catalytic activity for the synthsis of tert-butyl acetate. The molar ratio of tert-butanol to acetic anhydride is 31, the catalyst in total amount of reactant nearly 0.5%, and reaction time 6 h. With the above conditions, yield of the reaction could reach to 65%. The structure of product were verified by the FT-IR, Element analysis, and MS, which proved that the product was tert-butyl acetate.     

Thermal Shock Resistance of Al2 O3/ZrO2 (Y2O3) Composites

ZrO₂ containing 2% (mol fraction) Y₂O₃ and 3% (mol fraction) Y₂O₃ were added into Al₂O₃ matrix, compositing composites with 15% volume fraction of addictives mentioned above. The testing of property and analysis of SEM presented that, after vacuum sintering at 1550 °C, thermal shock resistance of two composites was superior to Al₂O₃ ceramic. The experiment showed that the properties of Al₂O₃ composites was higher than Al₂O₃ ceramic, and Al₂O₃/ZrO₂(3Y) was higher than Al₂O₃/ZrO₂(2Y) in thermal shock resistance. Improvement of thermal shock resistance of composites was attributed to many toughness machanisms of ZrO₂(Y₂O₃). By calculation, the fracture energy of Al₂O₃, Al₂O₃/ZrO₂ (2Y) and Al₂O₃/ZrO₂(3Y) was 38100.8 and 126.2 J·m⁻², respectively. Cracks initiation resistance (R') of Al₂O₃/ZrO₂(3Y) and Al₂O₃/ZrO₂(2Y) was higher than Al₂O₃ ceramic by 1.57 and 1.41 time, respectively, and cracks propagation resistance (R″″) was higher than Al₂O₃ ceramic by 1.46 and 1.38 time, respectively, which was corresponding to the results of residual strength.     

新型固体酸MnSO4/γ-Al2O3催化合成草酸二异戊酯

通过直接浸渍-焙烧法制备了新型固体酸MnSO4／γ-Al2O3催化剂，进行了表征，以草酸和异戊醇为原料合成了草酸二异戊酯，考察了MnSO4的负载量、催化剂的焙烧温度、催化剂用量、原料配比、反应时间、带水剂甲苯用量对反应的影响。结果表明，最佳的反应条件为：MnS04的负载量12.5％、催化剂焙烧温度550℃、催化剂用量1．5g、n（草酸）：n（异戊醇）=1：3、带水剂甲苯15mL、回流时间1．5h；在最佳反应条件下，草酸二异戊酯的收率可达99．2％，产品的纯度为99.6％。     

二氧化硅负载磷钨杂多酸催化合成环己酮乙二醇缩酮

采用浸渍制备了二氧化硅负载磷钨杂多酸催化剂。以环己酮和乙二醇为原料合成环己酮乙二醇缩酮,探讨了二氧化硅负载磷钨杂多酸催化剂对缩酮反应的催化活性,较系统地研究了原料量比、催化剂用量和反应时间诸因素对产品收率的影响。实验表明,二氧化硅负载磷钨杂多酸是合成环己酮乙二醇缩酮的良好催化剂,在n（环己酮）∶n（乙二醇）=1∶1.4,催化剂用量为反应物料总质量的0.4%,带水剂环己烷的用量为8ml和反应时间1.0h的优化条件下,环己酮乙二醇缩酮的收率可达87.3%。