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1.
以1,4-丁二醇、氢溴酸(48%)和冰醋酸为原料,在带水剂的作用下一锅法合成了4-溴丁基乙酸酯。考察了带水剂类型及追加冰醋酸或醋酸酐量对产率的影响,并通过气质联用对粗产品进行了分析测定,推断其反应机理。结果表明,较适宜的合成条件为1,4-丁二醇0.21 mol,1,4-丁二醇∶氢溴酸(48%)∶醋酸摩尔比为1∶1∶1.3,在带水剂甲苯(21 mL)的作用下,反应2.5 h,反应结束前1 h追加0.01 mol醋酸酐,合成效果最好,产率可达到91.2%,反应主要副产1,4-二溴丁烷、4-溴-1-丁醇、四氢呋喃和1,4-丁二醇二乙酸酯。 相似文献
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以乙二醇单乙醚和乙酸为主要原料,以四水硫酸铈为催化剂,环己烷为带水剂,合成了乙二醇单乙醚乙酸酯。采用IR、1HNMR等对其结构进行了确证,考察了乙二醇单乙醚和乙酸的摩尔比、催化剂种类和用量、带水剂用量、反应温度、反应时间等因素对反应的影响,得到了适宜的反应条件为:以0.2 mol乙二醇单乙醚为基准,n(乙酸)∶n(乙二醇单乙醚)=1.5∶1,m(四水硫酸铈)∶m(乙二醇单乙醚)=0.05∶1,环己烷9 mL,反应温度130℃,反应时间2.5 h。在该条件下,乙二醇单乙醚乙酸酯收率达97%以上。 相似文献
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《河南化工》2017,(4)
以La_2O_3为镧源,粗孔硅胶为载体,制备了新型稀土盐催化剂La_2(SO_4)_3/SiO_2。采用上述催化剂,以乙二醇乙醚和乙酸为原料,通过单因素法,考察了乙二醇乙醚与乙酸的物质的量比、催化剂、带水剂用量、反应温度、时间对反应的影响,得到了合成乙二醇乙醚乙酸酯的适宜的条件:以乙二醇乙醚0.2mol计,n(乙二醇乙醚)∶n(酸)=1∶1.5,m(La_2(SO_4)_3/SiO_2)∶m(乙二醇乙醚)=0.045∶1,带水剂环己烷10 m L,加热温度120℃,反应时间2 h,在此适宜条件下乙二醇乙醚乙酸酯收率达到96%以上。采用IR、核磁对产品进行了表征。 相似文献
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SO4^2-/TiO2固体超强酸催化合成苯乙酮乙二醇缩酮 总被引:1,自引:0,他引:1
本文报道了以SO42 -/TiO2 固体超强酸为催化剂 ,对苯乙酮和乙二醇为原料合成苯乙酮乙二醇缩酮的反应条件进行了研究。结果表明SO42 -/TiO2 固体超强酸是合成苯乙酮乙二醇缩酮的良好催化剂。最佳反应条件如下 :当苯乙酮的用量为 0 .2mol时 ,催化剂的活化温度为 5 0 0℃ ,n(苯乙酮 ) :n(乙二醇 ) =1 :1 .2 ,催化剂的用量为 1 .0克 ,反应时间 1 .5h ,甲苯为带水剂。在最佳条件下 ,缩酮的产率可达 97.8% ,纯度为 99.1 %。 相似文献
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在固体超强酸SO42-/ZrO2催化下,以乙二醇单乙醚和冰醋酸为原料,合成了乙二醇乙醚醋酸酯。考察了催化剂用量、物料配比、反应时间、带水剂等因素对反应的影响。实验结果表明,固体超强酸SO42-/ZrO2对合成乙二醇乙醚醋酸酯有着良好的催化活性,在催化剂用量为反应物料总质量的2%,乙二醇单乙醚9.01 g,n(乙二醇单乙醚)∶n(冰醋酸)=1∶3,回流时间2.5 h,带水剂环己烷用量为17 mL的条件下产品收率达95.8%,且催化剂重复使用5次仍保持较高活性。产品经红外、气质进行定性分析,确定结构为乙二醇乙醚醋酸酯。 相似文献
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2,7-二溴-9-亚(β-萘胺)基芴的合成 总被引:1,自引:0,他引:1
以芴为原料,通过空气氧化、水中溴代再与β-萘胺缩合,合成了2,7-二溴-9-亚(β-萘胺)基芴,较佳合成反应条件是:以四氢呋喃为溶剂,空气为氧化剂,n(芴):n(氢氧化钾)=1:2,室温反应6h,得芴酮,产率95.6%,再以芴酮为原料,水为溶剂,n(芴酮):n(溴)=1:2.5,回流反应10h,得2,7-二溴芴酮,然后以四氢呋喃为溶剂,冰乙酸为催化剂,n(2,7-二溴芴酮):n(β-萘胺)=1:1.3,回流反应12h,得2,7-二溴-9-亚(β-萘胺)基芴,产率为87.2%,所得产物的结构经IR、1HNMR、UV-Vis、MS和X射线单晶表征。 相似文献
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J. R. Aldrich S. P. Carroll W. R. Lusby M. J. Thompson J. P. Kochansky R. M. Waters 《Journal of chemical ecology》1990,16(1):199-210
Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA. 相似文献
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M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
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. 相似文献
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Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
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. 相似文献
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2008~2009年世界塑料工业进展 总被引:4,自引:1,他引:3
中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2010,38(3)
收集了2008年7月~2009年6月世界塑料工业的相关资料,介绍了2008~2009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、环氧树脂、不饱和聚酯树脂)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。 相似文献
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It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples. 相似文献
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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. 相似文献
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