SiO_2-Al_2O_3复合氧化物作为Pt负载型NO氧化催化剂载体的性能

采用共沉淀法制备Si O2-Al2O3复合氧化物载体,研究制备过程中陈化时间、Si O2与Al2O3物质的量比、焙烧温度以及硅前驱体对载体物化性能的影响,采用N2物理吸附仪、激光粒度仪、X射线衍射、NO程序升温脱附和扫描电镜对样品进行表征。分别在800℃和1 000℃条件下对载体进行高温老化,对比老化前后载体性能。采用浸渍法负载载体质量分数0.3%的Pt,制得Pt负载型NO氧化催化剂,对催化剂活性进行评价。结果表明,硅铝物质的量比为20∶80,陈化12 h,以硅溶胶为硅前驱体,500℃焙烧得到的载体负载Pt后达到预期的NO氧化效果,可以作为NO氧化催化剂用载体。     

过渡金属对Pt/SiC催化剂上CO氧化性能的影响

以SiC为载体、Pt为活性组分、过渡金属Fe、Co和Ni为助剂,采用浸渍法制备CO氧化催化剂。考察浸渍方法、助剂及其负载量、空速和催化剂焙烧温度等对Pt/SiC催化剂性能的影响。结果表明,助剂的加入提高了活性组分Pt在载体表面的分散度,并产生一定的相互作用,从而提高了催化剂活性,其中,铁助剂的助催化效果较好。共浸渍法制备的催化剂的催化活性优于分步浸渍法,Pt-Fe/SiC催化剂制备中焙烧温度500 ℃时,催化剂活性较佳,适量Fe助剂的添加能够显著提高Pt/SiC催化剂的活性。     

负载Pt的分子筛催化剂研究进展

阐述了分子筛催化剂负载Pt的研究进展,主要从分子筛负载Pt的制备方法、助剂、Pt前体以及处理条件变化对Pt/分子筛催化剂性能的影响等方面进行了阐述。Pt分散性对分子筛的催化性能具有重大影响,研究表明,通过以下手段可以有效改善Pt的分散性:通过共浸渍的方法引入Ce、Cr、Re、Sn等金属可以有效改善Pt的粒径分布,浸渍液中加入柠檬酸、乙二胺四乙酸作为竞争吸附剂可以有效改善催化剂中Pt的分散性,在焙烧过程中降低升温速度可以有效降低Pt的聚集,低浓度、多次浸渍可以提高Pt的分散性,氧气气氛下焙烧可以提高Pt的分散性,不同的Pt前体负载后Pt的粒径分布存在差异。Pt/分子筛催化剂在不同反应体系中的要求不一样,在具体反应体系中的研究有待进一步加深。     

一体式再生燃料电池双效氧电极催化剂

对一体式可再生燃料电池双效氧电极催化剂进行研究,考察了析氧催化剂和贵金属Pt黑组成的复合催化剂的双效性能以及催化剂配比和焙烧温度对性能的影响,用XRD对催化剂的物相特性进行表征。结果表明：复合催化剂的燃料电池性能按以下顺序递减：Pt黑＞Pt/Ru/Ir＞Pt/Ru＞Pt/IrO2～Pt/Ir＞Pt/RuO2;水电解性能按以下顺序递减：Pt/IrO2＞Pt/RuO2＞Pt/Ir＞Pt黑。分析比较,Pt/IrO2复合催化剂表现出良好的燃料电池/水电解双功能特性以及循环稳定性,具有最佳的URFC能量转换效率。因此,Pt/IrO2复合催化剂是最适宜的双效氧电极催化剂。一定温度范围内的焙烧处理对Pt/IrO2催化剂燃料电池性能影响不大,而对水电解性能具有一定的影响,大电流密度运行,未焙烧处理的Pt/IrO2催化剂表现出更好的水电解性能。     

Pt/TiO_2催化二甲醚部分氧化重整制氢

二甲醚是一种理想的氢载体,可用于解决氢的储存和运输。以Pt/TiO_2为部分氧化催化剂,结合Ni/Al_2O_3重整催化剂,考察钛前驱体和焙烧温度对二甲醚部分氧化重整制氢反应的影响。结果表明,以Ti(C4H9O)4为原料制备的TiO_2为金红石相,Ti(SO4)2或Ti O(OH)2为原料制备的TiO_2为锐钛矿相;以Ti(C4H9O)4为原料制备的Pt/TiO_2-E催化剂催化性能略好,转化率接近100%,H2收率约90%,表明金红石相TiO_2负载的Pt催化剂略佳;以Ti(SO4)2为原料制备的Pt/TiO_2-S催化剂500℃焙烧可获得金红石相TiO_2。与Pt/Al_2O_3催化剂相比,Pt/TiO_2催化剂具有更好的催化性能,H2收率超过90%,而Pt/Al_2O_3催化剂H2收率约80%。     

制备条件对固体超强酸Pt-SO_4~(2-)/ZrO_2-Al_2O_3异构化性能的影响

为了考察复合载体固体超强酸催化剂的异构化性能,研究了Pt-SO42-/ZrO2-Al2O3催化剂的制备条件,并以正戊烷异构化为探针反应,在高压微反-色谱联合装置上进行了实验。考察了焙烧温度、Al2O3质量分数、硫酸溶液浓度、Pt质量分数、活化温度等制备条件对催化剂性能的影响,采用XRD,BET,FT-IR等手段进行表征。结果表明,最佳制备条件为Al2O3质量分数5%,硫酸浸渍液浓度0.5 mol/L,Pt质量分数0.10%,650℃焙烧,300℃活化,所制备的催化剂在220℃时异戊烷收率达61.3%。该催化剂制备简单,绿色环保,具有工业应用潜力。     

Pt/Al_2O_3-TiO_2催化剂催化氯代硝基苯选择加氢活性探究

氯代苯胺(CAN)是染料、杀虫剂和医药等生产过程中的一种重要中间体,在化学工业、医药等行业有着广泛的应用。因此,研发合成氯代苯胺催化剂成为该领域的研究热点。采用浸渍-还原法制备了Pt基催化剂,以氯代硝基苯(CNB)为反应底物,在30℃、常压下系统考察了载体组成、载体焙烧温度、添加不同的水量等因素对催化剂加氢性能的影响,并运用XRD对复合氧化物载体进行表征。     

精C_5饱和加氢Pd/Al_2O_3催化剂的制备

研究负载在Al2O3载体上的Pd催化剂对精C5饱和加氢反应的性能。以工厂精C5为原料,考察载体焙烧温度、Pd负载量和催化剂制备工艺对催化剂性能的影响。结果表明,载体最佳焙烧温度为700℃,Pd最佳负载质量分数为0.3%,Pd最佳负载时间为4 h,催化剂最佳焙烧温度为500℃,催化剂最佳焙烧时间为4 h,以此条件制备的催化剂进行C5饱和加氢评价,加氢效率不低于94%。     

含氟芳香族硝基化合物加氢用钯催化剂的研究

介绍了以浸渍法制备Pd-Fe/SiO2催化剂,研究其载体、金属组分、还原剂、焙烧温度和时间等因素对催化剂催化性能的影响.确定了最优工艺条件:w(Pd)=5%,w(Fe)=0.2%,硼氢化钾作还原剂,焙烧温度500℃,焙烧时间4h.重复使用试验、优化验证试验、与其它催化剂如Raney Ni、Pt/C和Pd/C等对比试验结果表明,Pd-Fe/SiO2催化剂用于含氟芳香族硝基化合物的常压催化加氢反应,收率大于97.5%,纯度达到98.0%以上,选择性好,催化剂可重复使用10次.     

长链烷烃（n-C10~13）脱氢制单烯烃催化剂的研究Ⅰ.氧化铝载体孔结构对催化剂性能的影响

通过n-C_10～13烷烃脱氢反应考察了氧化铝载体孔结构对长链烷烃脱氢催化剂性能的影响,结果表明,氧化铝载体的总孔容对催化剂影响不大,而有效孔容（孔径分布）影响催化剂的反应性能。小孔对载体的比表面积起主要作用,并影响催化剂的Pt分散度;大孔为催化剂金属位的积炭迁移提供有效空间。Pt与载体的强相互作用对提高催化剂的活性和稳定性有利。     

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。