微波辐射纳米氧化钐催化合成草酸二丁酯

采用微波辐射技术,以纳米氧化钐为酯化反应催化剂合成草酸二丁酯。利用正交实验设计和单因素实验考察了微波辐射功率、微波辐射时间、催化剂用量、醇酸摩尔比等因素对酯化反应的影响。结果表明,纳米氧化钐催化剂在草酸二丁酯的合成中显示出良好的催化性能,而且该方法具有操作简便、反应速率快、节约能源等优点。在草酸用量为0.2mol、微波输出功率350W、辐射时间12min、催化剂用量为反应物总质量的1.0%、醇酸摩尔为4.0∶1的优化条件下,酯化率可达98.3%。     

硫醇硫醚类煤炭含硫模型化合物介电性质

煤中含硫杂质的微波响应特性是研究煤炭微波脱硫的基础性问题。本文选取了几种典型的硫醇硫醚类煤炭含硫模型化合物及其结构类似物,采用同轴空气线法测试了其在9 k Hz~6.5 GHz频率的介电性质。结果表明,ε′的大小关系为:三苯基甲硫醇三苯基甲醇二苯二硫醚二苄基硫醚联苄;ε″和tanδ的大小关系为:二苯二硫醚三苯基甲硫醇三苯基甲醇二苄基硫醚联苄。在频率2.2 GHz附近,可以实现二苯二硫醚和三苯基甲硫醇的选择性加热。     

微波辅助合成金丝桃素四磺酸衍生物

利用微波辅助合成的方法,对金丝桃素四磺酸衍生物合成路线中的大黄素蒽酮缩合反应分别从微波加热温度、辐射时间和催化剂3个因素进行了优化,确定了最佳反应条件:温度150℃,反应时间1 h,不使用催化剂;该步反应的产率可达82.2%,整个合成路线经放大后的总产率为65.3%。与常规加热方法相比,微波辅助合成法提高了反应效率和产率,减少了副反应的发生,使合成工艺更加低碳环保。     

聚氨酯/聚丙烯酸酯复合乳液的微波合成

微波技术操作简单、易于控制、反应时间短、合成产率高,将其应用于丙烯酸酯乳液的合成,是此领域中一个颇有价值的研究方向。本文以水性PU为种子乳液,以MMA、BA、MAA为单体,以APS为引发剂,以乳A、SDS和OP-10为复合乳化体系,采用微波加热聚合方式合成了聚氨酯/聚丙烯酸酯复合乳液并研究探讨了微波参数对乳液聚合的影响。结果表明:功率700W,温度85℃,反应时间30min为微波合成聚氨酯/聚丙烯酸酯复合的最佳反应条件。与传统的水浴加热方式相比,微波合成最明显的特点是具有高效率,当单体转化率达97%以上时,传统水浴加热需要3h,而微波加热仅需30min,其效率是前者的6倍。     

微波辐射四氯化锡催化合成草酸二丁酯的研究

本文研究了以SnCl4为催化剂,以草酸和正丁醇为原料,在微波辐射下合成草酸二丁酯的方法.通过实验得出最佳反应条件为:醇酸摩尔比为3.5:1,催化剂用量为总投料量的2%,微波辐射功率为480W,在此条件下取得了较好的收率.     

微波合成纳米氮化钛粉体的研究

以纳米级TiO2粉体、碳黑为原料,采用微波加热的方法合成氮化钛纳米粉体。探讨了微波合成温度、保温时间对生成率的影响。结果表明用微波加热的方法可以在较低的温度下合成纳米级氮化钛粉体。     

微波辐射蒙脱土固定三氯化铝催化合成草酸二丁酯

采用微波辐射技术,制备蒙脱土固定AlCl3固体酸催化剂。在密封灌内,通过微波辐射方法,用草酸与正丁醇为原料合成草酸二丁酯。研究结果表明,蒙脱土固定AlCl3固体酸催化剂具有良好的催化活性,当草酸用量0.02 mol,醇酸摩尔比为3.5∶1,催化剂用量为0.08 g,微波输出功率700 W,辐射时间11 min时反应的酯化率可达84.2%。     

微波加热在化学反应中的应用进展

介绍了微波加热的基本原理,并就微波加热在有机合成、高分子合成及加工、无机合成、天然气转化等方面的最新应用情况进行了综述分析,指出应加强微波对化学反应作用机理的研究。     

反应原料对微波碳热还原法合成AlN粉末的影响

根据微波加热特点,选择合适的反应原料,合成出优质的AlN粉末.结果表明,采用合适的反应原料微波合成AlN,由于微波的"非热效应"以及微波环境下整个反应系统的均匀加热,降低了反应温度,缩短了反应时间,极大的减少了合成成本.     

对氨基苯磺酸的微波合成

采用微波加热方法,用苯胺与浓硫酸反应生成对氨基苯磺酸。实验中分别从微波输出功率、微波辐射时间和投料比三个因素进行实验条件探讨,得出最佳的微波合成条件为:苯胺与浓硫酸两者的物质的量之比为1∶3,微波辐射功率为130W,微波加热时间12min。与传统加热方法合成对氨基苯磺酸对比后可知,微波辐射下反应速率至少是常规反应速率的30倍。     

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。