合成气直接制备低碳烯烃催化剂研究进展

以合成气一步法制备低碳烯烃的催化剂研发进展为切入点,归纳总结了一步法制备低碳烯烃的几类催化,包括双功能催化剂、铁基催化剂和钴基催化剂;重点阐述了设计合成催化剂过程中其性能的影响因素,如催化剂活性组分、载体、助剂、结构设计及制备方法;此外,还指出当前合成气一步法制备低碳烯烃催化剂的攻关难点,即克服产物分布影响、增加低碳烯...     

费托合成制低碳烯烃钴基催化剂研究进展

概述了费托合成制低碳烯烃的背景和发展趋势,综述了费托合成制低碳烯烃反应机理和钴基催化剂的研究进展,重点评述了钴基催化剂活性相、助剂和载体等关键因素,探讨了活性相、助剂和载体对合成气制低碳烯烃的影响,并对费托合成制烯烃的研究提出了展望和建议。     

甲醇制烯烃用ZSM-5分子筛的研究进展

综述了甲醇制烯烃用ZSM-5分子筛催化剂的研究进展,包括甲醇制低碳烯烃的合成机理、ZSM-5分子筛的结构与酸性对合成低碳烯烃性能的影响以及分子筛的改性。重点探讨了ZSM-5分子筛的改性（如水热处理改性、磷改性、氟改性、硼改性、金属离子改性及其他化学改性）对催化剂表面酸性和孔径、低碳烯烃选择性和催化剂稳定性的影响,指出分子筛孔径/表面酸性的调控和MTO/MTP反应机理的研究是甲醇制低碳烯烃催化剂研究的发展方向。     

生物质催化热解制备低碳烯烃的研究进展

随着我国原油对外依存度增加和国内烯烃供需矛盾加剧,烯烃原料供应紧张,制约了低碳烯烃行业发展。因此,扩大烯烃原料种类、采用非石油原料生产低碳烯烃有着重要意义。生物质作为原料用于制取烯烃有着广阔的研究前景。催化热解制备低碳烯烃工艺简单,克服了传统气化-合成技术制备过程复杂和周期长等缺点。然而,生物质催化热解制备低碳烯烃工艺过程也存在诸多影响因素,如生物质原料特性、催化剂类型和热解工艺条件等。本文着重讨论了原料种类、氢碳有效比、碱金属及碱土金属、温度、催化剂与原料比、反应装置、热解方式和催化剂种类等因素对低碳烯烃产率的影响,其中催化剂是提高低碳烯烃产率的关键因素。目前,ZSM-5分子筛催化剂广泛用于该工艺研究中;由于其易积炭快速失活,催化剂改性成为了研究的热点。针对现研究中改性方式较为单一且改性过程中存在的不足,提出了两种可行的分子筛改性方法。此外,鉴于还未见专门用于催化热解制备低碳烯烃的反应装置,文中给出了一个反应器设计参考性的意见。     

浅析影响煤制烯烃用双金属催化剂性能的因素

研究了合成气(CO和H2)直接合成低碳烯烃催化剂的制备。通过浆态床以及固定床反应器评价,并结合SEM、BET、XRD、TG、TPR等表征手段,研究不同金属在合成气合成烯烃过程中的主要作用,选择确定催化剂的活性组分及合适的助剂。结果表明,FeMnKCu作为合成烯烃的催化剂性能较好。     

由CO2合成乙醇和低碳烯烃

本文对CO2的性质以及由CO2合成乙醇和低碳烯烃的催化剂、反应机理作了介绍,并对由CO2合成乙醇和低碳烯烃的热力学函数?H°298、?G°298以及298K时的平衡常数Kp进行了计算. 计算结果表明,CO2+H2合成乙醇和低碳烯烃的反应是有利的化学过程,而CO2作氧化剂与低碳烷烃制烯烃的反应是吸热反应,并且Kp值很小,几乎为零,反应需要在高温下进行.     

由CO_2合成乙醇和低碳烯烃

本文对 CO2 的性质以及由 CO2 合成乙醇和低碳烯烃的催化剂、反应机理作了介绍 ,并对由 CO2 合成乙醇和低碳烯烃的热力学函数ΔH°2 98、Δ G°2 98以及 2 98K时的平衡常数 Kp进行了计算。计算结果表明 ,CO2 + H2 合成乙醇和低碳烯烃的反应是有利的化学过程 ,而 CO2 作氧化剂与低碳烷烃制烯烃的反应是吸热反应 ,并且 Kp值很小 ,几乎为零 ,反应需要在高温下进行     

合成气直接法制取低碳烯烃铁基催化体系研究进展

合成气直接法制取低碳烯烃因具有原料易得、流程简单和能源效率高等优势,成为了目前合成气应用领域一个新的热门研究方向。直接法转化方式主要有经由费托合成反应直接制取低碳烯烃（FTO）路径和经由氧化物-分子筛（OX-ZEO）过程直接制取低碳烯烃的双功能催化路线。本文简述了合成气制取低碳烯烃的主要工艺流程,重点聚焦在近年来费托合成反应直接制取低碳烯烃过程中铁基催化体系的研究进展,主要讨论了通过费托合成反应制取低碳烯烃中的反应机理,以及活性相、助剂和载体等因素对铁基催化剂反应性能的影响。此外,指出了当前研究存在的高低碳烯烃选择性与高反应活性难以兼得,产物中甲烷选择性过高等不足之处并对合成气直接法制取低碳烯烃的发展方向进行了展望。     

费托合成制低碳烯烃铁基催化剂研究进展

综述了费托合成制低碳烯烃铁基催化剂方面所取得的研究进展,重点介绍了催化剂活性相、助剂和载体等方面的关键因素,探讨了催化剂制备条件对合成气制烯烃的影响,最后对费托合成直接法制烯烃的研究提出了一些展望。     

二氧化碳加氢合成低碳烯烃的研究进展

大气中逐年升高的二氧化碳浓度对全球环境产生了严重的影响。通过可再生能源得到的H₂与CO₂反应生成低碳烯烃,不但可以使CO₂得到资源化利用,还能减少低碳烯烃的生产对于石油资源的依赖。该技术还有望实现从海水中得到燃油。本文主要对CO₂加氢合成低碳烯烃的热力学、反应机理和催化剂研究进行了综述。目前,该反应中使用的催化剂以Fe系为主。文中简要介绍了直接转化催化剂中的载体、助剂和双金属活性组分对反应性能的影响以及经甲醇路线制低碳烯烃的双功能催化剂在该反应中的应用。高性能催化剂的设计以及反应机理的探索是CO₂加氢合成低碳烯烃未来的发展方向。     

Insect antifeedant properties of anthranoids from the genusVismia

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.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

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.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

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.     

2007～2008年世界塑料工业进展

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.     

2005～2006年国外塑料工业进展

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。