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1.
采用浸渍法制备了系列负载型Ru-Ir双金属催化剂,用于催化对氯硝基苯的选择加氢.系统考察了不同制备方法和制备条件对催化剂性能的影响.实验结果表明,以γ-Al2O3为载体,用异丙醇共浸渍钌和铱,氢压为4.0 MPa,温度180 ℃,用氢气还原18 h 制备的双金属Ru-Ir催化剂(nRu :nIr=4:1,担载量为2.0%)具有较好的催化性能.该催化剂用于对氯硝基苯加氢还原反应中,在反应温度60 ℃,氢气压力为2.0 MPa,底物与催化剂的摩尔比为1000:1条件下,反应1 h,转化率可达90.4%,目标产物对氯苯胺的选择性达99.5%.  相似文献   

2.
制备了两种PVP稳定的负载型稀土金属催化剂, 考察了其催化邻氯硝基苯(o-CNB)选择加氢制备邻氯苯胺(o-CAN)的催化性能. 所用氢气通过乙醇的液相催化重整产生并直接用于邻氯硝基苯的原位加氢. 评价了不同反应条件(温度、时间、Fe修饰剂等)对邻氯硝基苯的选择加氢的影响. 研究表明, PVP-La/γ-Al2O3催化剂比另一贵金属催化剂PVP-Pd/γ-Al2O3拥有更好的催化性能. 同时, 在优化的条件下, Fe修饰的PVP-La/γ-Al2O3催化剂催化的邻氯硝基苯选择加氢反应中, o-CNB的转化  相似文献   

3.
目的制备氯和研究了氯代硝基苯液相加氢选择性催化剂。方法分别以纳米碳管(CNTs),γ-Al2O3为载体,Ni-B为活性组分,用浸渍-化学还原法制备CNTs负载非晶态合金Ni-B/CNTs催化剂和Ni-B/γ-Al2O3催化剂,用电感耦合等离子体光谱、X-射线衍射、透射电子显微镜、差示扫描量热等手段研究催化剂的非晶性质、Ni的担载量及催化剂的热稳定性,并讨论了CNTs和Ni-B非晶态合金之间的相互作用与催化剂的催化性能的关系。结果与其他催化剂相比,3种氯代硝基苯的转化率均高于99.8%,脱氯率小于3%。结论该催化剂具有较好加氢性能和较高的抑制脱氯性能,优于其他催化剂。  相似文献   

4.
考察了水溶性Ru/Pd—TPPTS双金属催化剂催化卤代芳香硝基化合物的加氢性能.实验结果表明,在原位合成的Ru—TPPTS催化体系中添加PdCl2后,催化剂的活性明显提高,尤其是0.50Ru/0.50Pd—TPPTS双金属催化剂表现出显著的钌和钯之间的双金属协同效应.在PB2=1.0MPa,70℃,反应70min的条件下,双金属催化剂0.50Ru/0.50Pd—TPPTS催化对-氯硝基苯中硝基选择性加氢反应时转化率达到100%,生成对-氯苯胺选择性为92.3%.对于取代基和取代位置不同的一些卤代硝基苯加氢,双金属催化剂0.50Ru/0.50Pd—TPPTS也表现出很高的催化活性和较高的生成卤代苯胺选择性.  相似文献   

5.
考察了γ-Al2O3负载的二十面体金属Pd纳米颗粒对邻氯硝基苯的催化氢化反应,初步探讨了该催化剂的催化性能.在氢压1 MPa、温度50℃、反应时间2 h的条件下,邻氯硝基苯转化率可达100%,邻氯苯胺的选择性可达65.4%;添加适当的金属离子可缩短氢化反应时间,转化率100%,邻氯苯胺的选择性可提高至88.1%.  相似文献   

6.
辛癸酸甘油酯催化加氢脱氧反应规律   总被引:3,自引:0,他引:3  
以辛癸酸甘油酯为模型化合物,采用高压流动反应装置考察辛癸酸甘油酯在金属硫化物加氢催化剂CoMo/γ-Al2O3,NiMoP/γ-Al2O3,NiMoP/γ-Al2O3-HUSY和贵金属双功能催化剂Pt/SAPO-11催化剂上的加氢脱氧反应规律.结果表明:辛癸酸甘油酯在加氢催化剂上的反应包括加氢饱和、脱羧、异构化和裂化反应,主要产物为烷烃;采用Pt/SAPO-11催化剂的催化加氢产物中异构化烷烃比例明显提高,脱羧反应和裂解反应得到明显抑制.  相似文献   

7.
为控制多氯硝基苯加氢制备多氯苯胺的深度脱氯,在Pd/C催化剂制备中,考察了硝酸浓度、催化剂还原温度和时间对催化剂上Pd粒径及催化加氢活性和选择性的影响。结果表明:Pd粒径的增大导致催化剂对多氯硝基苯的催化活性下降,但多氯苯胺的选择性上升;随着硝酸浓度的增加,Pd的分散性和粒径先增大后减少,而还原温度和时间的增加可增大Pd的粒径;采用15%硝酸处理、200~250℃下氢气还原4~5 h可获得较理想的Pd粒径为16~20 nm的Pd/C催化剂;对五氯硝基苯加氢还原呈现较高的加氢活性和选择性,转化率可达99%以上,五氯苯胺选择性可达96%以上。  相似文献   

8.
负载Pt催化剂在卤代硝基苯氢化反应中的催化性能研究   总被引:9,自引:0,他引:9  
考察了常压、303K反应条件下,γ—Al2O3、TiO2和ZrO2上负载的铂催化剂在卤代硝基苯的氢化反应中的催化性能,同时考察了过渡金属(Cr,Mn,Fe,Co,Ni和Cu)改性Pt/ZrO2的催化性能.不同负载的铂催化剂加氢活性次序为:Pt/TiO2>Pt/γ—Al2O3>Pt/ZrO2,相应的对氯苯胺(p—CAN)选择性次序为:Pt/TiO2>Pt/ZrO2>Pt/γ—Al2O3.KBH4处理过的催化剂显示了较高的催化活性.Mn、Fe和Co的引入同时提高了Pt/ZrO2催化剂的催化活性和p—CAN选择性.PtNi/ZrO2催化剂随着Ni含量的增加,催化活性降低,但产物p—CAN的选择性都超过99%.  相似文献   

9.
γ-Al2O3负载的Pt,Pd催化剂上邻二甲苯的深度催化氧化   总被引:1,自引:0,他引:1  
采用浸渍法制备了不同负载量的Pt/γ-Al2O3,Pd/γ-Al2O3及Pt-Pd/γ-Al2O3双金属催化剂并用于邻二甲苯的深度催化氧化.研究发现,在上述单金属催化剂中,Pd/γ-Al2O3的催化活性明显优于Pt/γ-Al2O3;将一定量的Pt添加到Pd/γ-Al2O3中形成Pt-Pd/γ-Al2O3双金属催化体系时,目标污染物的转化率和二氧化碳的产率较单金属催化剂都有显著增加,表明贵金属Pt的添加对Pd/γ-Al2O3的活性有促进作用.同时发现,Pt-Pd/γ-Al2O3具有良好的稳定性,是一种很好的深度催化氧化苯系污染物的催化剂.  相似文献   

10.
为了考察了Mn与Zn摩尔配比以及不同碱金属盐修饰制得的锰锌复合氧化物催化剂对苯甲酸甲酯气固催化加氢合成苯甲醛反应活性和选择性的影响,在氢酯比为1.5的条件下,进行苯甲酸甲酯催化加氢反应,发现以5%LiCl修饰的活性组分负载量为25%、n(Mn)/n(Zn)为1.14的MnOZnO /γAl2O3催化剂,在常压、430 ℃、空时为1.84 h时,苯甲酸甲酯的转化率为97.71%,苯甲醛的选择性为84.80%.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

14.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

17.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

18.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
1 Rise of studies on climate change's effects on biodiversity
Until the 1980s, climate change and biodiversity were studied as two independent disciplines for more than a century. In 1992, the Ecological Society of America's annual report named climate change, biodiversity, and the sustainable ecological system as the three major global environmental issues of the twenty-first century [1].  相似文献   

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