双金属交换的Cu-Mn/SSZ-39催化剂的NH3-SCR脱硝性能

以SSZ-39为载体,采用离子交换法制备不同铜锰物质的量比的Cu-Mn/SSZ-39分子筛催化剂,并考察其在以NH3为还原剂的选择性催化还原NO反应(NH3-SCR)中的脱硝活性.通过XRD、SEM、N2吸脱附、NH3-TPD、H2-TPR、XPS、ICP等对催化剂的结构、形貌、表面酸性等进行表征.结果表明,Cu2+提供主要的反应活性位,使催化剂具有良好的脱硝活性和N2选择性;Mn2+/3+交换提高了催化剂的表面酸性,特别是增加了弱Lewis酸的含量;Cu2+、Mn2+/3+双金属交换的Cu-Mn/SSZ-39催化剂具有良好的低温脱硝活性和水热稳定性.当Cu与Mn的物质的量比为1:0.6时,Cu-Mn(0.6)/SSZ-39具有最低的起燃温度(T50为125℃),在184～433℃的宽温度范围内NO转化率达到90％以上,并在450℃内保持90％以上的N2选择性.水热老化后的Cu-Mn/SSZ-39-A基本保持了原有的晶型、形貌和脱硝活性,体现了良好的水热稳定性.     

非贵金属改性钒钛基催化剂NH3-SCR脱硝协同控制VOCs

在钒钛基催化剂上分别负载四种非贵金属(Ce、Cu、Mn、Fe)，研究改性催化剂对中低温选择性催化还原(SCR)脱硝协同挥发性有机物(VOCs)催化氧化的性能。对四种负载金属(Ce、Cu、Mn、Fe)分别进行SCR脱硝和VOCs催化氧化，发现Ce改性的催化剂在低温段具有良好的SCR脱硝活性和VOCs催化氧化性能，被认为具有良好的协同催化潜力。之后对Ce掺杂改性催化剂进行协同评价研究，发现在275～300℃的温度区间内，3V-5Ce/Ti催化剂的NO转化率和VOCs转化率可达到100%。并分别比较了SCR反应协同VOC与未协同VOC时N₂的选择性和CO₂的选择性，发现在低温段时甲苯的引入会显著降低N₂选择性，而随着温度升高，N₂O副产物的产生，N₂的选择性恢复到未引入甲苯时。同时发现协同反应时CO2的选择性有明显下降。对3V-5Ce/Ti催化剂的SEM、XRD、XPS、NH3-TPD表征说明Ce的引入不会破坏载体形貌，可以为催化剂提高更多表面氧空位，从而提高催化剂的氧化还原性能，并...     

MnOx-SnO2/TiO2型催化剂低温NH3选择性催化还原NO

采用分段负载的方式制备了MnOx-SnO2/TiO2型催化剂,并将其用于NH3选择性催化还原NO中,在280～600℃温度区间对该催化剂的脱硝活性进行了测试,同时也考察了催化剂的抗硫耐水性能。实验结果表明,该催化剂在130～250℃温度范围内NO的转化率接近100%,并且表现出较好的抗硫耐水性能。氮吸附-脱附、XRD和NH3-TPD等表征结果表明,较大的比表面积、无定形态的Mn、较强的酸性位以及Mn、Sn、Ti之间的强相互作用是该催化剂活性较高的主要原因。     

M(0.1)Mn(15)/Hβ催化剂的低温NH3选择还原NO性能

NH₃选择性催化还原（NH₃-SCR）氮氧化物可有效减少固定源NOx的排放,目前,工业上应用的钒钛体系催化剂活性窗口温度为(300~400) ℃,不能用于低温脱硝,开发低温NH₃-SCR烟气脱硝催化剂成为研究热点之一。采用浸渍法制备M(0.1)Mn(15)/Hβ（M=Ni、Fe、Mg、Ca、Sr,0.1为M与Mn物质的量比）系列催化剂。通过X射线衍射、扫描电子显微镜和H2-程序升温还原反应等方法对催化剂进行表征,在固定床微型反应器上考察催化剂NH3选择还原NO的催化性能。结果表明,加入金属助剂Ni,催化剂活性得到改善,反应温度降低,T85和T95分别为157 ℃和 171 ℃。     

SSZ-13分子筛的水热合成及应用研究

以硅溶胶、氢氧化铝为原料,N,N,N-三甲基-1-金钢烷基氢氧化铵为模板剂,采用水热法合成出较高结晶度的SSZ-13分子筛。采用低廉的铜胺配合物为辅助模板剂合成出较高结晶度的Cu-SSZ-13分子筛。采用离子交换法和浸渍法对SSZ-13分子筛制备出Cu/SSZ-13催化剂。相比Cu/ZSM-5催化剂,Cu/SSZ-13催化剂具有更优异的脱硝活性和更宽的活性窗口。用SSZ-13和Cu-SSZ-13分子筛制备的催化剂样品(29)90%NO_x转化率的高活性温度窗口分别为220~480℃、280~460℃。     

立方相纳米氧化锆基催化剂脱硝机理研究

以纳米c-ZrO2为载体,用浸渍法制备出MnOx-CeO2/c-ZrO2催化剂,考察了组分负载量、反应温度对催化剂NH3-SCR脱硝活性影响,探讨了催化剂表面织构特征,分析了催化剂脱硝活性机理.结果显示,增加活性组分负载量和反应温度,催化剂脱硝效率增加,100℃时,2.5％ MnOx-CeO2/c-ZrO2脱硝效率为65.3％,15％ MnOx-CeO2/c-ZrO2脱硝效率达97.9％.XRD、BET、XPS、H2-TPR表征结果表明,负载后催化剂表面织构对脱硝反应有利.NH3-TPD测试显示,MnOx-CeO2/c-ZrO2催化剂表面Lewis酸位为强酸性位,NH3吸附在Lewis酸性位形成配位态NH3,经生成NH2 NO最后分解为N2和H2O.     

基于NH3-SCR反应铜基小孔分子筛催化剂Na中毒对比研究

以浸渍法模拟碱金属中毒NH₃-SCR催化剂过程，制备不同Na含量（质量分数）的铜基小孔分子筛Cu/SSZ-13和Cu/SAPO-34，对比研究了二者的碱金属中毒机理。结果表明，外引Na离子均可严重影响两种催化剂的NH₃-SCR催化活性，造成催化剂的晶相结构坍塌，酸性量减少，活性物种减少。不同的是，Na引入量较低（<1.82%）时，Cu/SAPO-34比Cu/SSZ-13具有更强的Na离子耐受性，而当Na含量高于3.48%时，Cu/SAPO-34几乎完全丧失NH₃-SCR催化活性。通过催化剂的结构表征（BET、XRD和SEM）和酸性位表征（DRIFTS、NH₃-TPD和H₂-TPR），研究表明随着Na中毒程度的加深，Cu/SSZ-13的结构破坏是渐变式的，而Cu/SAPO-34的结构破坏是突变式的；Na中毒的机理研究表明，酸性位的减少是Cu/SSZ-13的SCR活性下降的主导原因，结构坍塌是Cu/SAPO-34的SCR活性下降的主导原因。     

Mn-Fe-Ce/TiO2低温NH3选择性催化还原NO

采用浸渍法制备了MnO2-Fe2O3-CeO2/TiO2催化剂用于低温NH3选择性催化还原烟气中NO,考察了Mn, Fe, Ce含量及焙烧温度对NH3选择性催化还原NO的活性和抗水性能的影响. 在气体体积空速(GHSV)=24000 h-1, NH3/NO=0.8(j), 350℃煅烧和烟气含3%(j) O2的条件下,该系列催化剂的脱硝活性为MnO2-Fe2O3-CeO2/TiO2>MnO2- Fe2O3/TiO2>MnO2/TiO2,且在200℃时MnO2(10)-Fe2O3(5)-CeO2(5)/TiO2的脱硝率为95%. 对含10%(j)水蒸汽的烟气,MnO2(10)-Fe2O3(5)-CeO2(5)/TiO2的脱硝活性维持在87%;在10%(j)水蒸汽和100′10-6 SO2共存条件下,短时间内脱硝活性维持在55%.     

Cu/SSZ-13催化剂脱硝活性中心与催化性能构效关系的研究

NH₃选择性催化还原NO_x（NH₃-SCR）是目前最有应用前景的柴油车尾气净化技术,该技术的核心是开发具备优异催化性能的催化剂。以具有菱沸石（chabazite,CHA）结构的小孔分子筛SSZ-13为载体制备的Cu/SSZ-13催化剂,因具有优异的催化性能和水热稳定性能而受到广泛关注。制备了系列Cu_x/SSZ-13催化剂,并通过CO原位漫反射红外光谱（DRIFT）和H₂-TPR等方法能够确定具有高催化活性的铜离子在SSZ-13分子筛上的落位和存在状态。CO红外吸附实验发现,采用Cu(NO₃)₂水溶液离子交换法制备的Cu/SSZ-13催化剂上存在多种落位的Cu⁺活性中心。在较低的Cu⁺交换度条件下,Cu⁺优先落位于SSZ-13分子筛的八元环位置,随着交换度的提高,Cu⁺开始落位于SSZ-13分子筛双六元环的位置。H₂-TPR结果表明Cu_x/SSZ-13催化剂上也存在大量落位在八元环位置不稳定的Cu²⁺,这些Cu²⁺很容易被还原为Cu⁺。Cu_x/SSZ-13催化剂经800℃水蒸气连续老化16 h,分子筛骨架崩塌程度随着Cu含量的增加而提高,骨架铝的脱除,导致Cu物种发生团聚,而第二金属Ce元素的引入能够在一定程度上提高Cu/SSZ-13的水热稳定性。催化剂构效关系研究表明,具有一定量稳定存在的Cu⁺,并且拥有大量不稳定存在Cu²⁺的催化剂具有较宽温度范围的脱硝性能。     

V2O5/AC催化剂吸附NH3及其选择性还原脱硝活性

在不同活性焦(Activated Coke, AC)载体上以等体积浸渍法负载V2O5,制备出一系列V2O5/AC催化剂. 通过NH3暂态响应实验和NH3穿透时间实验考察了在200℃下V2O5/AC的表面积、灰分、表面官能团和V2O5对NH3的吸附量及NO的选择性催化还原活性的影响. 结果表明,对于载体未经硝酸处理的催化剂,NH3的吸附位主要是V2O5(参与脱硝反应的NH3的吸附量与催化剂上V2O5负载量的比值为1:5),活性焦及其中的灰分对NH3的吸附量很小;硝酸处理在活性焦表面引入的含氧和含氮酸性官能团对参与脱硝反应的NH3的吸附量是V2O5上吸附量的1.3倍,这些官能团不影响V2O5对NH3的吸附;活性焦上吸附的NH3的脱硝活性很低,但可迁移至V2O5上参与脱硝.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。