1-甲基咪唑醋酸离子液体催化合成甲基丙烯醛

合成了1-甲基咪唑醋酸（[Mim]Ac）质子型离子液体,对其进行了1H NMR和IR表征。以[Mim]Ac为催化剂,甲醛、丙醛、二乙胺为原料,通过Mannich反应制备了甲基丙烯醛。考察了原料投料比、[Mim]Ac用量、Mannich反应温度和反应时间等因素对甲基丙烯醛收率的影响。研究结果表明,当甲醛、丙醛和二乙胺的摩尔比为1.1：1.0：1.0,[Mim]Ac用量（物质的量）为丙醛的10.0%,Mannich反应温度为45℃,反应时间为50 min,分解反应温度为75℃,甲基丙烯醛的收率为95.3%,并对产物进行了1H NMR表征。同时,对[Mim]Ac质子型离子液体催化Mannich反应的机理进行了初步研究。     

甲醛和丙醛Mannich缩合制备甲基丙烯醛

甲基丙烯醛（MAL）作为一种重要的有机合成中间体，在医药农药、香精香料、工业助剂、水泥减水剂等领域应用非常广泛。甲醛和丙醛Mannich缩合法合成MAL具有反应条件温和、操作简单、副产物少等优点。本文概述了MAL的工业应用、Mannich缩合反应机理，着重阐述了甲醛和丙醛的Mannich缩合催化剂及反应工艺的研究进展。文中指出，目前Mannich缩合制MAL采用的均相催化体系及工艺，催化剂用量大且难以分离和循环利用，环境污染严重，成本较高；多相催化体系的应用解决了催化剂的分离和重复利用问题，但目前催化剂活性和选择性较低。因此，未来的研究应该重点关注：①开发高效的新型均相催化剂以及相应的连续反应工艺，降低催化剂用量；②开发高性能的多相催化剂，提高催化剂的活性和选择性。     

2-羟基-3-甲基-3-丁烯腈的合成

通过甲醛与丙醛在盐酸二乙胺催化下缩合合成了 2 甲基丙烯醛 ,收率为 98%。反应操作分两阶段进行 ,第一阶段反应的pH值为 7,温度为 45℃ ;第二阶段反应在沸腾状态下进行 ,通过蒸馏得到产品。催化剂重复使用 4次对反应收率无显著影响。 2 甲基丙烯醛与氰化钠、盐酸在强烈搅拌 ,反应温度≤ 5℃下反应得 2 羟基 3 甲基 3 丁烯腈 ,收率 92 %。产品结构用1H NMR进行了确定。     

甲醛和丙醛缩合制备甲基丙烯醛反应动力学

通过气相色谱和傅里叶红外光谱仪分析,考察了不同仲胺化合物对甲醛和丙醛缩合制备甲基丙烯醛的催化性能. 结果表明,二乙胺催化效率最高,甲基丙烯醛的收率高达94%. 进一步研究了以二乙胺为催化剂缩合制备甲基丙烯醛的反应动力学规律,得出反应级数为2.456,反应活化能和指前因子分别为62.45 kJ/mol和8.182′107 (mol/L)-1.456/s. 并通过在线红外光谱仪和气质联用仪证实生成了中间体曼尼希碱,为进一步研究反应机理奠定了基础.     

二羟甲基丙酸合成工艺研究

以正丙醛、甲醛和双氧水为主要原料,经羟醛缩合、氧化反应制备2,2-二羟甲基丙酸,重点考察了缩合、氧化反应条件。经实验验证,最佳反应条件为:n(正丙醛):n(甲醛):n(双氧水)=1:2.4:1.4,缩合反应温度35℃左右,缩合反应时间6h;氧化反应温度80℃左右,氧化反应时间6h。反应液采用真空浓缩,冷冻结晶,重结晶等工艺处理,2,2-二羟甲基丙酸产品总收率大于55%。     

二乙醇胺/磷酸催化甲醛和丙醛缩合制备2-甲基丙烯醛

以二乙醇胺和磷酸的混合物替代三乙胺盐酸盐作催化剂催化甲醛和丙醛缩合制备2-甲基丙烯醛,优化的反应条件为:丙醛和甲醛物质的量比为1:1.05,室温下先加催化剂,后加甲醛,搅拌下加入丙醛.2-甲基丙烯醛收率达95％(以丙醛计),纯度为97％,优于三乙胺盐酸盐作催化剂时的反应结果.     

丙烯醛温和液相反应制备3-甲基吡啶工艺

以丙烯醛为原料,通过单因素实验,建立了优化的温和液相反应合成3-甲基吡啶的优化工艺条件：以乙二醇单丁醚为溶剂,反应温度140℃,料液比n(丙烯醛):n(乙二醇单丁醚)=1:33,n(丙烯醛):n(乙酸铵)=1:8,w(丙烯醛正丁酸溶液)=8%,m(丙烯醛):m(SO24-/TiO2-HZSM-5催化剂)=1:1.4。在优化条件下,实现了丙烯醛转化率100%,3-甲基吡啶选择性49.92%。     

以二氯甲烷为溶剂对乙酰基二茂铁Mannich反应的研究

利用乙酰基二茂铁的活性α-H的性质进行了乙酰基二茂铁Mannich反应研究,先以磷酸为催化剂,醋酐为酰化剂合成了乙酰基二茂铁,然后探讨在二氯甲烷为溶剂的情况下,乙酰基二茂铁与二乙胺、甲醛的Mannich反应。考察了反应温度、物料摩尔比和反应时间及催化剂的用量对反应条件的影响,并通过红外、质谱对产物进行了表征。确定了以二氯甲烷为溶剂乙酰基二茂铁Mannich反应的合成工艺:乙酰基二茂铁、甲醛、二乙胺的摩尔比为1.0∶2.0∶3.0;操作方式为先加入二乙胺和甲醛,10 min后滴加体积分数为36%盐酸调解pH值在4—6之间,20min后滴加乙酰基二茂铁的二氯甲烷溶液,控制反应温度为50—52℃,反应7 h,产率为77%。     

磷钼酸催化合成2,2-二羟甲基丙醛的研究

以磷钼酸作为催化剂,催化甲醛与丙醛的羟醛缩合反应,合成2,2-二羟甲基丙醛。研究了磷钼酸对此缩醛反应的催化反应活性,以及催化剂的用量、反应物配比、反应时间等因素对反应产物收率的影响,确定了最佳催化条件。结果表明,在甲醛(mol)∶丙醛(mol)=2.2∶1,催化剂用量为反应物质量的1.5%,反应时间为4h,温度为30℃的条件下二羟甲基丙醛的收率为54.1%     

2,2-二甲基-3-羟基丙醛的合成工艺研究

以异丁醛和甲醛为原料,三乙胺为催化剂,羟醛缩合法合成了2,2-二甲基-3-羟基丙醛。考察了物料比、加料方式、反应温度和反应时间对反应结果的影响,同时考察了产品的分离精制工艺。在物料比n(异丁醛)∶n(甲醛)∶n(三乙胺)为1∶1.1∶0.02、反应温度61～65℃的优化反应条件下,反应4～5h,所得产品经水洗、减压、蒸馏和结晶后,2,2-二甲基-3-羟基丙醛收率达到95%,纯度为99%以上。     

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。