Prediction of density and viscosity of ternary systems [C_2q]Br＋[C_4q]Br＋H_2O, [C_2q]Br＋[C_6q]Br ＋H_2O, and [C_4q]Br＋[C_6q]Br＋H_2O at different temperatures using their binary subsystems data

The simple equations for prediction of the density and viscosity of mixed electrolyte solutions were extended to the related properties of mixed ionic liquid solutions. The density and viscosity were measured for ternary solutions [C2q]Br(N-ethylquinolinium bromide)+[C4q]Br (N-butylquinolinium bromide)+H2O, [C2q]Br+[C6q]Br(N-hexylquinolinium bromide)+H2O, and [C4q]Br+[C6q]Br+H2O and their binary subsystems [C2q]Br+H2O, [C4q]Br+H2O, and [C6q]Br+H2O at 15, 20 and 25 °C, respectively. The results were used to test the predictability of the extended equations. The comparison results show that these simple equations can be used to predict the density and viscosity of the mixed ionic liquid solutions from the properties of their binary subsystems of equal ionic strength.     

Activity of Co(Ni)MoS/Al2O3 catalysts, derived from cobalt(nickel) salts of H6[Co2Mo10O38H4], in hydrogenolysis of thiophene and hydrogen treatment of diesel fraction

Co(Ni)MoS/Al₂O₃ catalysts have been prepared from ammonium 10-dodecamolybdodicobaltate (NH₄)₆[Co₂Mo₁₀O₃₈H₄] (further, Co₂Mo₁₀HPC) and cobalt(nickel) salts of 10-dodecamolybdodicobaltic acid H₆[Co₂Mo₁₀O₃₈H₄] (hereinafter, Co₂Mo₁₀HPA). It has been found that a high activity of the Co(Ni)₃-Co₂Mo₁₀HPA/Al₂O₃ catalysts in the hydrodesulfurization and hydrogenation reactions is due to the formation of a nanostructured type II CoMoS phase via the contact of the metals (Mo and Co(Ni)) at the molecular level. The use of Ni as a copromoter in the Ni₃-Co₂Mo₁₀HPA/Al₂O₃ catalyst leads to a simultaneous increase, compared with Co₃-Co₂Mo₁₀HPA/Al₂O₃, in the linear size of nanoparticles and the number of MoS₂ layers in the packing of active phase. The nature of the promoter X has a substantial effect on the properties of X₃Co₂Mo₁₀HPC/Al₂O₃ catalysts. It has been found that the catalysts with X = Co exhibit the highest activity in the hydrodesulfurization reactions and those with X = Ni, in hydrogenation reactions.     

煅烧还原一步制备Ni基催化剂及在CH4-CO2重整反应中的应用

采用大豆油研磨法制备了Ni/C-SiO_2系列催化剂,并用于CH_4-CO_2重整反应。通过XRD、TG-DTG、BET、H_2-TPR、CO_2-TPD等对催化剂进行了物理性能表征,利用固定床连续反应对催化剂进行了催化性能测试。结果表明,研磨法制得的催化剂前驱体在惰性气氛N2中煅烧后,催化剂上的镍元素全部转变成了Ni~0,实现了煅烧还原一步制备中孔Ni基催化剂。CH_4-CO_2重整反应后的催化剂上存在两种炭,一种是催化剂制备时残留的碳源炭,另一种是重整反应过程中产生的可致催化剂失活的积炭。考察了助剂CeO_2、ZrO_2、La_2O_3对催化剂性能的影响,结果表明,与Ni/C-SiO_2催化剂相比,Ni-CeO_2/C-SiO_2、Ni-ZrO_2/C-SiO_2、Ni-La_2O_3/C-SiO_2催化剂中Ni~0的粒径降低了,Ni-CeO_2/C-SiO_2、Ni-La_2O_3/C-SiO_2催化剂的反应活性提高了,反应后Ni-ZrO_2/C-SiO_2、Ni-La_2O_3/C-SiO_2催化剂上的积炭减少了。助剂La_2O_3不仅提高了催化剂活性,而且降低了催化剂上的积炭量,使用Ni-La_2O_3/C-SiO_2催化剂进行CH_4-CO_2重整反应,总碳转化率达到了52%。     

Co掺杂对CuO/ CeO2-Co3O4优先氧化CO催化性能的影响

采用共沉淀-浸渍法制备了一系列不同Ce/Co物质的量比的CeO₂-Co₃O₄载体和CuO负载量(质量分数)为7% 的CuO/CeO₂-Co₃O₄催化剂,考察了它们在富氢气氛中对CO的优先氧化性能。采用BET、XRD、H₂-TPR等对催化剂进行了表征。测试结果表明:Ce/(Co+Ce)物质的量比为0.9时,CuO/ CeO₂-Co₃O₄催化剂活性最好。少量的Co掺杂有利于提高催化剂的比表面积和铜物种在载体上的分散,少量的Co进入了CeO₂的晶格,增强了钴铈相互作用,进而提高了载体的氧化还原性能。      

介孔CuO/SiO2用于汽油氧化-吸附脱硫

 利用[(C₁₆H₃₃) N(CH₃)₃]₃-[PW₁₂O₄₀]双亲催化剂与H₂O₂组成的催化氧化体系对汽油进行氧化后,以介孔SiO₂为载体等体积浸渍法制备的介孔CuO/SiO₂为吸附剂,采用固定床连续流动式吸附脱硫评价装置,考察了CuO/SiO₂的CuO负载量、焙烧温度、焙烧时间和吸附温度对汽油脱硫率的影响,并对介孔CuO/ SiO₂吸附剂性质进行了XRD表征。结果表明,采用在焙烧温度为400℃、焙烧时间为2.0 h、CuO负载量为2%制备的CuO/SiO₂, 在吸附温度为120℃时,汽油氧化-脱硫的脱硫效果较好,汽油脱硫率可达56.82%。     

劣质重油脱碳改质接触剂上焦炭气化反应规律

采用微型固定床反应器,研究了劣质重油流化脱碳改质接触剂上焦炭与O₂、H₂O(g)和O₂+H₂O(g)混合气的气化反应,考察了反应温度、气化剂组成、反应时间对气体产物组成以及焦炭转化率的影响。结果表明,采用O₂为气化剂时,焦炭气化反应的主要产物CO与CO₂的摩尔比(n(CO)/n(CO₂))随反应温度提高先升高后降低。采用H₂O(g)为气化剂时,焦炭气化产物主要由H₂、CO、CO₂及微量CH4组成;在1025~1149 K范围,反应温度对气化产物组成的影响较小,反应温度1025 K、反应时间多于25 min时,气体产物中CO+H₂的体积分数在87%以上,反应温度高于1049 K时,焦炭转化率明显提高。采用O₂-H₂O(g)混合气作为气化剂,且气化剂中O₂体积分数较低时,焦炭气化反应产物组成与采用H2O(g)作为气化剂时的类似,但随着O₂体积分数增加,产物中H2体积分数大幅下降;气化剂中O₂体积分数大于10%时,产物中H₂体积分数几乎为零,产物组成与采用O2作为气化剂时的类似;焦炭转化率随着O₂体积分数和反应温度的升高而增加。     

H6P2W18O62/MCM-48催化剂的制备、表征及催化绿色合成己二酸

以MCM-48为载体,通过浸渍法制备了H6P2W18O62/MCM-48催化剂,并采用FT-IR、XRD、SEM、EDS对催化剂进行表征。以微波促进30%(质量分数)H2O2氧化环己酮合成己二酸反应为探针,考察了H6P2W18O62/MCM-48的催化性能,并通过正交实验确定了优化的工艺条件。结果表明,采用H6P2W18O62负载量40%的H6P2W18O62/MCM-48催化剂,在优化的合成己二酸的工艺条件下,即催化剂质量分数(以环己酮质量计)5.1%、n(C6H10O)∶n(H2O2)∶n(H2C2O4.2H2O)=100∶450∶1.88、反应温度95℃、微波功率300 W、反应时间3.5h,己二酸收率可达81.3%;催化剂重复使用5次,己二酸收率仍可达到64.6%。     

Ni/La-BaTiO3催化剂的低温CH4/CO2重整性能研究

镧液相掺杂合成了不同镧含量的La-BaTiO3载体,再通过浸渍负载活性组分制备出Ni/La-BaTiO3催化剂。通过CH4/CO2连续重整制合成气反应,考察常压下、700℃和750℃温度的Ni/La-BaTiO3催化剂稳定性和积炭性能;采用CO2脉冲反应评价了700℃低温重整条件下各Ni/La-BaTiO3催化剂上一氧化碳的歧化反应程度。结果表明,一氧化碳的歧化反应程度对催化剂低温CH4/CO2重整的稳定性和积炭性能影响显著,Ni/1.05%La-BaTiO3是最佳的低温CH4/CO2重整催化剂。     

非均匀分布Pd/Al2O3催化剂活性组分Pd的迁移及其对加氢性能的影响

 研究了具有壳层结构的负载型Pd/Al₂O₃催化剂在裂解汽油选择性加氢过程中活性组分Pd的迁移现象.测定了生产装置所用新鲜催化剂和再生催化剂的比表面积、孔容和其中活性组分Pd含量,采用TEM和SEM-EDS方法表征了Pd的分散性.结果表明, 在裂解汽油选择性加氢的工艺过程中, 具有壳层结构的负载型Pd/Al₂O₃催化剂的永久性失活和选择性改变的主要原因之一是活性组分Pd的迁移. Pd迁移的基本原因是其在催化剂颗粒中的不均匀分布, 助金属组分可以限制Pd的迁移, 从而改善催化剂的性能.     

高效镍基氨分解催化体系中载体作用的研究

 选用无水乙醇为溶剂，采用浸渍法制备了纳米结构的Ni/Al₂O₃、Ni/La-Al₂O₃、Ni/MgO和Ni/TiO₂催化剂，并在常压连续微反装置上分别对其氨分解反应活性进行评价。结果表明，4种负载型镍催化剂的活性顺序为Ni/La-Al₂O₃ > Ni/Al₂O₃ >> Ni/TiO₂ > Ni/MgO。当反应温度为600℃时，Ni/La-Al2O3催化剂上H2的生成速率可达873 mmol/g(Ni)min。对不同Ni负载量的Ni/La-Al₂O₃催化剂进行XRD分析表明，即使Ni负载量高达14%，活性组分在载体上仍然呈高度分散状态。载体对镍基氨分解催化剂的表观活化能具有显著影响。其中，当Ni负载量为3%时，Ni/Al₂O₃、Ni/La-Al₂O₃、Ni/MgO和Ni/TiO₂催化剂的反应活化能分别为108、119、102和120 kJ/mol。当载体相同时，催化剂氨分解活性主要受反应活化能的影响，反应活化能越高，氨分解活性越低。     

临氢条件下NiMoS/γ-Al2O3催化辛烯-1与H2S的反应

 在高压反应釜中临氢条件下研究了NiMoS/γ-Al₂O₃催化辛烯-1与H₂S的反应,考察了反应温度、H₂S含量和烯烃体积分数对反应产物的影响,对反应产物进行GC-MS分析,探讨了辛烯-1与H₂S的反应机理。结果表明,辛烯-1与H₂S反应主要生成硫醇类和硫醚类化合物,辛烯-1本身还会发生加氢饱和反应和双键迁移异构化反应。随着反应温度升高,反应产物中的硫醇硫和总硫的量均逐渐减少,同时促进了辛烯-1的加氢饱和反应。反应体系中H₂S的含量越高,产物中硫醇硫和硫醚硫的含量越大;而且H₂S还会促进辛烯-1的双键迁移异构化反应,抑制辛烯-1的加氢饱和反应。随着反应体系中辛烯-1体积分数增大,产物中总硫的含量不断增大,而硫醇硫的含量先增大后减小,此外,辛烯-1的异构化产物和加氢饱和产物也会随之不断增多。     

Facile preparation of Cr2O3 nanoparticles and their use as an active catalyst on the thermal decomposition of ammonium perchlorate

ABSTRACT

Cr₂O₃ nanoparticles were prepared by repeated wet mechanical milling technique. Three drying methods, oven drying, vacuum drying, and vacuum freeze-drying were comparatively used to dry Cr₂O₃ nanoparticles. These processes can be easily scaled up to 10-kg quantities. It took only 2–3 h to cut bulk size to nanometer by milling. The obtained Cr₂O₃ nanoparticles are semi-spherical and homogeneous with an average size of 30 nm measured by SEM and TEM and show similar diffraction peak positions to bulk one investigated by XRD. The TG/DSC study indicated that, compared with bulk Cr₂O₃, Cr₂O₃ nanoparticles obtained by oven drying and vacuum drying, the catalytic performance of Cr₂O₃ nanoparticles obtained by vacuum freeze-drying is the best in lowering the peak temperature of high temperature decomposition and the activation energy, while increasing the apparent decomposition heat and the reaction rate constant of ammonium perchlorate (AP) due to their good dispersion and large specific surface area. The possible catalytic mechanism of Cr₂O₃ on the thermal decomposition of AP was proposed by TG-MS analysis. These findings showed that wet mechanical milling technique combined with vacuum freeze-drying technology is suitable for efficient preparation of Cr₂O₃ nanoparticles, which could be a promising additive for accelerating the thermal decomposition of AP.     

复合SiO2-WO3催化剂的制备、表征及氧化脱除苯并噻吩性能

 采用溶胶-凝胶法制备了SiO₂-WO₃催化剂,并采用XRD、FT-IR、BET、TG-DTA等方法对催化剂进行表征。以苯并噻吩(BT)为模型化合物,H₂O₂为氧化剂,考察了催化剂的活性元素、制备方法、n(W)/n(Si)和焙烧温度对其催化氧化脱硫活性的影响。结果表明,W的引入降低了SiO₂的比表面积,SiO₂-WO₃催化剂中W的主物相为WO₃。在以W为活性组元,且n(W)/n(Si)为0.1时,500℃焙烧得到的SiO₂-0.1WO₃催化剂具有最好的催化脱硫活性。在模拟油20 mL、催化剂SiO₂-0.1WO₃用量0.04 g、n(H₂O₂)/n(S)为15.9、乙腈/模拟油体积比0.3、65℃反应60 min的条件下,苯并噻吩模拟油脱硫率可达99.3%。     

Optimal activated carbon for separation of CO2 from (H2 + CO2) gas mixture

Seven types of activated carbon were used to investigate the effect of their structure on separation of CO₂ from (H₂ + CO₂) gas mixture by the adsorption method at ambient temperature and higher pressures. The results showed that the limiting factors for separation of CO₂ from 53.6 mol% H₂ + 46.4 mol% CO₂ mixture and from 85.1 mol% H₂ + 14.9 mol% CO₂ mixture were different at 20 C and about 2 MPa. The best separation result could be achieved when the pore diameter of the activated carbon ranged from 0.77 to 1.20 nm, and the median particle size was about 2.07 lm for 53.6 mol% H₂ ? 46.4 mol% CO₂ mixture and 1.41 lm for 85.1 mol% H₂ + 14.9 mol% CO₂ mixture. The effect of specific area and pore diameter of activated carbon on separation CO₂ from 53.6 mol% H₂ ? 46.4 mol% CO₂ mixture was more significant than that from 85.1 mol% H₂ ? 14.9 mol% CO₂ mixture. CO₂ in the gas phase can be decreased from 46.4 mol% to 2.3 mol%–4.3 mol% with a two-stage separation process.     

The Role of Nitrogen in Facilitating Methylcyclohexane Aromatization on Pt/Al2O3 and Pt-Re/Al2O3 Catalysts

Abstract

The kinetics of methylcyclohexane aromatization on commercial Pt/Al₂O₃ and Pt-Re/Al₂O₃ catalysts was investigated in a micro-reactor using N₂ and/or H₂ as carrier gases at temperatures ranging between 300–500°C, W/F values ranging between 0.83–3.75 mg min/mL and at a total pressure of 4.0 kg/cm². On both catalysts in N₂ atmosphere, aromatization accompanied by demethylation was observed with the formation of cracked products, benzene and toluene. However, in H₂ methane was the predominant product of methylcyclohexane reforming on PtA1₂O₃ and Pt-Re/Al₂O₃ at 500°C and 400–500°C respectively, whereas at 350°C, aromatization was predominant on Pt/Al₂O₃ but on Pt-Re/Al₂O₃, aromatization was accompanied by fragmentation to methane. In N₂–H₂ mixtures, demethylation activity was observed to decrease with H₂ content of the mixture on Pt-Re/Al₂O₃. A preliminary test of the kinetic data using Sica's method of pulse kinetic analysis suggests a first order rate in methylcyclohexane with activation energies of 3.21 kcal/gmol in N₂ and 19.70 kcal/gmol in H₂ for the Pt/Al₂O₃ catalyst and 16.66 kcal/gmol in N₂ and 34.94 kcal/gmol in H₂ for the Pt-Re/Al₂O₃ catalyst. However, a more comprehensive kinetic analysis suggested an aromatization mechanism for Pt-Re/Al₂O₃, where adsorbed H₂ was a participant. A different aromatization mechanism for the reaction in N₂ where hydrogen was not needed explained the data on Pt/Al₂O_3. In both cases, the desorption of toluene was determined as the rate determining step.     

NaAlO2溶液中铝酸根离子的微观结构

 应用IR、²⁷Al NMR 和UV3种波谱方法对不同方式配制的Al₂O₃浓度和苛性系数基本相同的四种NaAlO₂溶液进行了详细的表征。结果表明IR、²⁷Al NMR和UV3种光谱方法给出的信息可以相互补充支持,共同给出NaAlO₂溶液中铝酸根离子的微观结构。溶液配制方式对NaAlO₂溶液中铝酸根离子的微观结构具有显著影响,4种NaAlO₂溶液中铝酸根均以四配位[Al(OH)₄]^-为主体离子,可以排除六配位[Al(OH)₆]^3-的存在; 二聚[Al₂O(OH)₆]^2-含量因配制方式不同存在显著差别,在方式Ⅰ配制的溶液中二聚[Al₂O(OH)₆]^2-含量很少或不存在,在方式Ⅱ、Ⅲ、Ⅳ配制的溶液中显著存在二聚[Al₂O(OH)₆]^2-,在溶液Ⅱ、Ⅲ中还存在尚未确定结构的离子。     

孔径双峰分布γ-Al2O3负载NiMoP催化剂的制备及对蜡油加氢催化性能

在氢氧化铝干胶挤条成型时,调节纳米炭黑的加入量和水/粉质量比,制备了孔径呈双峰分布、具有较大孔容和比表面积的γ-Al2O3载体。当炭黑加入质量分数为13%、水/粉质量比1.15时,制备的孔径呈双峰分布的γ-Al2O3载体的孔容为0.80mL/g、比表面积为309m2/g,4～10nm和10～15nm孔径分别占总孔容50.8%和35.1%(体积分数),采用该载体制备的NiMoP/γ-Al2O3催化剂的孔径呈明显的双峰分布。在反应温度370℃、氢分压10MPa、氢/油体积比700、体积空速1.5h-1的条件下,制备的NiMoP/γ-Al2O3催化剂可使减压和焦化混合蜡油的硫质量分数由25600μg/g降至2070μg/g,脱硫率为91.9%,而参比催化剂仅可使减压和焦化混合蜡油硫质量分数降至3450μg/g,脱硫率为86.5%。     

Influence of Anderson and Keggin heteropoly compounds as precursors of oxide phases in hydrotreating catalysts on their performance

Unpromoted and nickel-promoted catalysts were synthesized on the basis of the Anderson heteropoly compounds (NH₄)_{6 ? x} [X ^x (OH)₆Mo₆O₁₈] · nH₂O, where heteroatom X is Cr(III), Mn(II), Fe(II), Ni(II), Co(II), Cu(II), Zn(II), or Ga(III), and their activity in the thiophene hydrogenolysis reaction and hydrofining of diesel fraction was examined. It was shown that the most active hydrotreating catalysts under the test conditions in a flow unit were the samples with X = Ni, Mn, or Zn. The catalysts synthesized from the Keggin heteropoly compounds H₄[SiMo₁₂O₄₀] · 17H₂O, H₃[PMo₁₂O₄₀] · 19H₂O, H₃[PVMo₁₁O₄₀] · nH₂O, and (NH₄) _x [V(MoO₃)₁₂] · nH₂O were tested in the hydrofining of light coker gas oil. The maximum activity was displayed by the catalysts prepared on the basis of the vanadium-containing heteropoly compounds H₃[PVMo₁₁O₄₀] · nH₂O and (NH₄) _x [V(MoO₃)₁₂] · nH₂O.     

Effect of composition of tungsten(VI) and phosphorus(V) peroxoheteropoly derivatives on the efficiency of epoxidation of olefins under phase-transfer catalysis conditions

Epoxidation of hexene-1 and cyclohexene in the systems H₂WO₄/H₂O₂-H₂O/H₃PO₄ was studied under the phase-transfer catalysis conditions depending on the ratio between the reactants Na₂WO₄ and H₃PO₄ (in the presence of excess H₂O₂) and pH of the water phase. The interrelation between the pH of the aqueous phase, the composition of phosphatooxoperoxotungstate ions formed, and the catalytic activity of the systems was established. The complexes Q₃[PO₄{WO(O₂)₂}₄] and Q₂[HPO₄{WO(O₂)₂}₂], where Q⁺ is the lipophilic cation of a phase-transfer agent whose nature can have a noticeable effect on the composition of peroxoheteropoly compounds formed, exhibited the highest activity. To achieve the maximum catalytic activity, it is necessary to maintain the stoichiometric reactant ratio corresponding to the composition of peroxo complexes that prevail in a given pH range.