四聚乙醛合成反应的研究

本文对由乙醛合成四聚乙醛的反应条件进行了探讨,发现DMSO对此反应有阻缓作用,并找到了一种有效的催化剂和溶剂,使四聚乙醛的产率可达13.7％,是文献值的4.88倍。     

四聚乙醛的制造和应用

本文综述了文献中,由乙醛制造四聚乙醛的几种主要方法。其制备工艺由乙醛的聚合和三聚乙醛的解聚二部分组成。简要地介绍了四聚乙醛在固体燃料、人工降雨催化剂及防治蜗牛杀虫剂中的应用。     

四聚乙醛的制造和应用

本文综述了文献中,由乙醛制造四聚乙醛的几种主要方法。其制备主艺由乙醛的聚合和三聚乙醛的解聚二部分组成。简要地介绍了四聚乙醛在固体燃料、人工降雨催化剂及防治蜗牛杀虫剂中的应用。     

甲维盐和四聚乙醛复配对福寿螺的联合毒力测定

[目的]测定甲维盐和四聚乙醛对福寿螺的联合毒力及田间防效,在海南采用浸螺法测定了药剂间的增效作用,并加工成颗粒剂进行了田间试验。[结果]甲维盐对福寿螺(2龄)的LC50值为0.104 mg/L,四聚乙醛的LC50值为1.242 mg/L,四聚乙醛与甲维盐在10∶1～80∶1范围内均显示了增效作用,11%四聚乙醛·甲维盐颗粒剂在200、300 g/667m2剂量下对福寿螺显示了很好的防效,防效为86.37、93.46%,显著高于对照药剂6%四聚乙醛颗粒剂。[结论]甲维盐和四聚乙醛是防治福寿螺的优异替代药剂。     

四聚乙醛合成的研究

本研究使用盐酸复合催化剂合成四聚乙醛（Ⅰ）的方法。在该催化剂和温度－15－15℃下,由乙醛（Ⅱ）聚合生成Ⅰ和三聚乙醛（Ⅲ）。反应混合物经分离得固体和母液。固体经水洗、稳定和烘干得高纯Ⅰ;母液中主要含Ⅲ,在浓硫酸解聚剂和加热下,解聚回收Ⅱ。该方法既极大地降低了工艺条件,又使Ⅰ得率达15－20％。操作简便易行,工艺技术先进,具有很好的经济效益。     

气相色谱法对乙醛多聚体的质量全分析

采用气相色谱法 ,结合校正因子 ,研究了四聚乙醛、三聚乙醛、乙醛和烟酰胺的测定条件。该方法科学 ,操作易行、快速 ,准确度达到工业分析的要求。     

快速测定回收乙醛主要成分的方法探讨

从聚酯生产过程产生的废水中提取回收乙醛具有巨大的经济效益,但是乙醛在生产和存储过程中会发生聚合反应,同时乙醛具有易燃易挥发的特点,因此,方便快捷地测定乙醛纯度对乙醛回用生产和存储具有重要指导意义。经过试验,采用气相色谱法对回收乙醛中的三聚乙醛、四聚乙醛和其他杂质进行精确分析,确立了如下气相色谱条件:安捷伦毛细管柱HP-5,进样口温度120℃,柱温50℃,检测器温度140℃,载气为N2,载气压力50 kPa。     

气相色谱法对乙醛多聚体的质量全分析

用气相色谱法，结合校正因子，研究了四聚乙醛、三聚乙醛、乙醛和烟酰胺的测定条件。方法科学，操作易行、快速，准确度达到工业分析的要求。     

气相色谱法测定乙醛及其杂质含量

建立了气相色谱法测定乙醛及其杂质含量的方法,采用SH-Rtx-5毛细管柱分离,氢火焰离子化检测器检测。在选定的色谱条件下,乙醛与其杂质能得到有效分离,并能获得较好的检测效果。分析结果表明,乙醛的质量浓度在0～5.24 g/L范围内线性关系良好,线性相关系数为0.999 7,加标回收率为97.78%～101.66%,变异系数为0.59%;杂质丁烯醛、三聚乙醛、四聚乙醛的质量浓度分别在0～23.34 mg/L、0～124.38 mg/L、0～24.22 mg/L范围内线性关系良好,线性相关系数分别为0.9993、0.9994、0.9996;加标回收率分别为95.89%～99.23%、9 6.17%～100.52%、95.62%～100.66%;变异系数分别为2.38%、0.90%、4.44%;最低检出浓度分别为3.74、3.59、4.84μg/m L。     

我国乙醛产业的发展动态

综述了我国乙醛的发展历史。介绍了我国乙醛产业的发展动态和生产工艺,并提出了发展建议。     

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。