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1.
黄媛玉  缪建文 《化工时刊》2005,19(11):13-16
用X-光电子能谱(XPS)研究SrTiO2体系上不同Sr/Ti比、B位不同价态掺杂元素和掺杂量的催化剂组成、表面吸附氧含量与甲烷氧化偶联(OCM)催化性能.结果表明Sr/Ti比增加、B位掺杂元素(Zr,Al,Mg)价态降低和B位Mg2+掺杂量增加会导致催化剂表面吸附氧含量的增加,并与催化剂的C2产物选择性有顺变关系,但表面吸附氧含量过高会导致甲烷的深度氧化.  相似文献   

2.
国秀梅  陈洪钫 《化工学报》1995,46(3):310-316
在1%Sr/La_2O_3-Bi_2O_3-Ag-YSZ氧泵型催化膜反应器中,进行了甲烷氧化偶联反应动力学研究,提出了反应途径及机理,并建立了速率方程。结果表明,在该氧泵型催化膜反应器中,甲烷氧化偶联反应满足Rideal-Rdox机理。采用固体电解质电位测定技术进行了内扩散影响的考察。  相似文献   

3.
国秀梅  陈洪钫 《化工学报》1995,46(3):304-309
本文采用1%Sr/La_2O_3-Ag-YSZ氧泵型催化膜反应器进行了甲烷氧化偶联反应研究。比较了不同制备方法的催化膜的反应性能,结果发现浸涂法(Ag-YSZ管随旋转轴转动涂制)制备的膜性能最佳。研究了操作条件对甲烷氧化偶联反应的影响。研究证明,传递氧与气相氧同时进料是一种较好的反应方式。结果表明,利用该反应器不仅可以简化分离过程,而且还可得到更高的C_2烃选择性。  相似文献   

4.
本文采用1%Sr/La_2O_3-Ag-YSZ氧泵型催化膜反应器进行了甲烷氧化偶联反应研究。比较了不同制备方法的催化膜的反应性能,结果发现浸涂法(Ag-YSZ管随旋转轴转动涂制)制备的膜性能最佳。研究了操作条件对甲烷氧化偶联反应的影响。研究证明,传递氧与气相氧同时进料是一种较好的反应方式。结果表明,利用该反应器不仅可以简化分离过程,而且还可得到更高的C_2烃选择性。  相似文献   

5.
本文介绍了氧泵型反应器构造、原理和固体氧离子电解质的性能表征.通过对催化剂、氧泵的作用、催化膜制备方法及反应历程几方面近期来研究的叙述和总结,分析了氧泵型甲烷氧化偶联的研究现状,介绍了NEMCA效应及其研究手段和主要结论.对氧泵型反应器甲烷氧化偶联存在的问题和今后的研究方向提出了看法.  相似文献   

6.
甲烷活化与转化是当今催化研究领域的前沿课题。本文对甲烷氧化偶联制乙烯、甲烷芳构化、甲烷部分氧化制合成气的催化剂进行了介绍。  相似文献   

7.
氧泵型反应器及在甲烷氧化偶联反应中的应用   总被引:2,自引:0,他引:2  
马忠龙  陈洪钫 《化工进展》1998,17(5):36-39,57
本文介绍了氧泵型反应器构造、原理和固体氧离子电解质的性能表征。通过对催化剂、氧泵的作用、催化膜制备方法及反应历程几方面近期来研究的途述和总结,分析了氧泵型甲烷氧化偶联的研究现状,介绍了NEMCA效应及其研究手段和主要结论。对氧泵型反应器甲烷氧化偶联存在的问题和今后的研究方向提出了看法。  相似文献   

8.
乙烯是重要的化工基础原料,生产方式主要是石油裂解,随着石油资源的日益匮乏,寻找新的乙烯生产路线成为研究重点。我国天然气储量丰富,甲烷氧化偶联(OCM)制乙烯工艺路线得到研究者的广泛关注。OCM路线是能够替代石油资源生产烯烃的重要途径,也是高效清洁利用天然气的重要发展方向。本文综述甲烷氧化偶联制乙烯的反应过程以及催化剂类型,对不同类型催化剂的OCM性能进行对比,具体分析提高甲烷氧化偶联催化性能的关键因素,有利于推进OCM催化剂的研究进程。  相似文献   

9.
介绍了膜催化技术在甲烷转化反应中的应用,这些过程包括甲烷氧化偶联反应制乙烯,甲烷部分氧化制甲醇,甲烷水蒸气重整制合成气等,通过膜催化反应与传统催化反应的比较,揭示了膜催化技术的优点。  相似文献   

10.
采用甲烷和甲苯作为催化交叉氧化偶联的评价反应,考察了Al2O3、MgO、CaO、TiO2及其负载碱金属催化剂。在不同碱金属含量、不同反应条件下进行了活性和选择性的研究,并提出了交叉氧化偶联的可能机理。  相似文献   

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Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.  相似文献   

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14.
Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.  相似文献   

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17.
In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.  相似文献   

18.
Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.  相似文献   

19.
收集了2007年7月~2008年6月世界塑料工业的相关资料,介绍了2007~2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.  相似文献   

20.
收集了2005年7月~2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、通用热固性树脂(酚醛、聚氨酯、不饱和树脂、环氧树脂)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。  相似文献   

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