氮杂环丙烷[3+2]环加成反应研究进展

介绍了最近几年在不同催化体系下,氮杂环丙烷与含双键化合物的[3+2]环加成反应研究进展。     

功能化分子筛催化氮杂环丙烷与异硫氰酸酯[3+2]环加成反应的研究

主要研究了固体酸催化剂对氮杂环丙烷与异硫氰酸酯间的[3+2]环加成反应的催化效果,并对反应展开了一系列底物拓展。实验结果表明,在该催化体系下,反应都有不错的收率。并且通过催化剂重复性实验,也可以发现,经过多次重复利用的固体酸也可以起到有效的催化作用。     

氮杂环丙烷与双键化合物的[3+2]环加成反应研究进展

咪唑烷、恶唑烷和吡咯烷等五元氮杂环在有机合成的应用十分广泛,而氮杂环丙烷与不饱和双键化合物的[3+2]环加成反应是合成此类化合物的一种便捷高效的方法。综述了近年来氮杂环丙烷与亚胺、烯烃、醛酮等含有双键化合物的[3+2]环加成反应研究进展,并对其发展方向进行了展望。     

金属配合物催化CO_2转化为环碳酸酯的进展

利用CO_2与环氧化合物的环加成反应制备环碳酸酯,具有100%的原子经济性、环境友好等特点,有利于缓解温室气体效应,有着重要的理论和现实意义。开发新颖、高效的催化体系是该反应顺利快速进行的关键所在。近年来,金属配合物催化体系在环氧化合物和CO_2环加成反应应用最多,催化效果最为出色。综述了金属配合物催化体系如主族金属、过渡金属、镧系金属以及3d-4f金属催化剂等在CO_2与环氧化物环加成反应领域的研究进展,为今后合成新型高效金属配合物催化体系提供重要参考。     

离子液体在CO2环加成反应中的应用

离子液体(ILs)作为一种新型的"绿色溶剂",因其具有热稳定性好、挥发性低、结构可设计性等优点被广泛应用在CO_2环加成反应中。综述了由ILs催化CO_2与环氧化物的环加成反应制备环状碳酸酯的研究进展,从反应相态的角度将ILs催化剂分为普通ILs催化剂和负载ILs催化剂,分别阐述了其催化性能。简要分析了ILs催化剂目前存在的主要问题,并对ILs在CO_2环加成反应中的应用进行了展望。     

多金属氧酸盐催化反应的研究进展

介绍了近年来多金属氧酸盐作为友好催化剂在化学反应催化方面的应用:氧化反应、酸催化反应、有机叠氮环加成反应、CO_2环加成反应、偶联反应。     

氮杂环丙烷与腈的[3+2]环加成反应生成咪唑啉的研究进展

咪唑啉是一种非常重要的药物中间体,其通过氮杂环丙烷与腈的[3+2]环加成反应是非常有效合成方法.综述了这种方法的研究进展,并且进行了评价与展望.     

离子液体辅助催化CO_2与环氧丙烷合成环碳酸酯

Zn-Fe双金属氰化物(DMC)催化剂通过清洁高效的机械球磨法来制备,并以咪唑类低共熔溶剂为助催化剂,通过协同催化二氧化碳(CO2)与1,2-环氧丙烷(PO)的环加成反应合成环碳酸酯(PC)。利用一系列技术表征手段对主催化剂与环加成产物PC的结构及其性能进行了测试表征。结果表明,咪唑类离子液体可有效辅助主催化剂催化CO2与PO的环加成反应,离子液体可改善该进程的催化活性和产率。     

离子液体辅助催化CO_2与环氧丙烷合成环碳酸酯

Zn-Fe双金属氰化物(DMC)催化剂通过清洁高效的机械球磨法来制备,并以咪唑类低共熔溶剂为助催化剂,通过协同催化二氧化碳(CO2)与1,2-环氧丙烷(PO)的环加成反应合成环碳酸酯(PC)。利用一系列技术表征手段对主催化剂与环加成产物PC的结构及其性能进行了测试表征。结果表明,咪唑类离子液体可有效辅助主催化剂催化CO2与PO的环加成反应,离子液体可改善该进程的催化活性和产率。     

温和条件下催化吖丙啶与二氧化碳环加成反应合成(噁)唑烷酮

本文以环氧丙烷为原料,在氨水或有机胺的作用下开环得到β-氨基醇,然后采用Wenker方法合成了吖丙啶和1-甲基吖丙啶;采用双功能亲电—亲核催化体系(Jacobsen催化剂/季铵盐)在温和条件下催化吖丙啶或1-甲基吖丙啶与二氧化碳进行环加成反应,得到区域选择性的唑烷酮。在该催化体系下,通过1-甲基吖丙啶与二氧化碳的环加成反应首次得到了高区域选择性的3,4-二甲基唑烷-2-酮,通过1HNMR对其结构进行表征。     

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。