脱氢枞酸在空气中的热分解动力学

采用TG/DTA/DSC热分析技术,在线性升温速率为5、10、15和20 K·min^-1和静态空气条件下,研究了脱氢枞酸在空气气氛中的热分解动力学。由热重/差热法(TG/DTA)得到脱氢枞酸在空气中是一步分解;运用差示扫描量热法(DSC)测定了脱氢枞酸的熔点为445.05K,摩尔熔化焓为19.74 kJ·mol^-1和摩尔熔化熵为44.35J·mol^-1·K^-1;分别利用Kissinger法和Flynn-Wall-Ozawa法对脱氢枞酸非等温热分解数据进行了动力学分析,同时利用Satava-Sestak法研究了脱氢枞酸的热分解机理。结果表明,脱氢枞酸的热分解机理为收缩球状界面反应模型R3,热分解反应的表观活化能为107.89 kJ·mol^-1,指前因子为9.33×10⁸ s^-1)。     

Pd/C上松香催化歧化反应集总动力学

以松香为原料、改性Pd/C为催化剂、200#油为溶剂及N2为保护气，进行松香催化歧化反应集总动力学的研究。在消除内外扩散影响的条件下，在线跟踪48315～53315 K的反应产物并用毛细管柱气相色谱法测定反应体系组成随时间的变化关系。根据松香歧化反应机理和特点，借鉴集总思想和方法，按结构族组成和动力学相近原则划分该复杂反应体系的集总组分，构建了Pd/C上松香歧化集总反应网络，建立了枞酸型树脂酸、海松酸型树脂酸、氢化枞酸型树脂酸、氢化海松酸型树脂酸和脱氢枞酸五集总动力学模型；采用Levenberg-Marquart法，以Matlab编程和SPSS数理统计软件估算了模型参数，得到枞酸型树脂酸脱氢、加氢，海松酸型树脂酸加氢反应过程的活化能分别为11139 kJ·mol-1、10876 kJ·mol-1、9735 kJ·mol-1，结果表明，所建动力学模型与实验数据吻合良好，并能预测反应在54315 K的集总组分浓度分布。     

超声波作用下脱氢枞酰甘氨酸表面活性剂的合成与表面活性

以脱氢枞酸与氯化亚砜制得脱氢枞酸酰氯,脱氢枞酸酰氯和甘氨酸在超声波作用下生成脱氢枞酰甘氨酸,超声波的固定功率为120 W,讨论了反应温度、时间及反应物的用量比对反应的影响。结果表明,最佳的反应条件为:脱氢枞酸酰氯和甘氨酸物质的量之比为1∶1(摩尔比),反应温度20~25℃,反应时间70 m in,产率可达73.81%。并且对脱氢枞酰甘氨酸钠和脱氢枞酰甘氨酸钾的表面活性进行了测试。     

脱氢枞酸单离方法的比较研究

以歧化松香为原料、气相色谱为分析手段进行了脱氢枞酸单离方法的比较。分别采用胺化法、皂化法和超声波强化胺化反应结晶耦合法单离脱氢枞酸,并对不同的歧化松香原料进行了单离脱氢枞酸的研究,实验结果表明,采用自制的歧化松香为原料,超声波强化胺化反应结晶耦合法在 40℃ 时单离脱氢枞酸的效果最好,纯度达 99.99%,收率达 55.37%,并用GC、UV、IR、熔点仪和旋光仪对所制备的高纯度脱氢枞酸进行了分析鉴定,实验值与文献值基本一致。     

反应-结晶耦合单离脱氢枞酸过程研究?

以歧化松香和2-乙醇胺为原料,采用超声波强化的方法进行反应-结晶耦合单离脱氢枞酸过程研究.考察了反应时间、反应温度、超声波强度、溶剂浓度、搅拌转速、胺盐结晶溶剂浓度、重结晶次数及结晶方式对脱氢枞酸收率的影响,实验结果表明,超声波可以有效地强化歧化松香胺化反应-结晶过程,适宜的反应时间为40min、反应温度为35℃、超声波功率为300W、溶剂浓度为40%、搅拌转速为300r·min-1、胺盐结晶溶剂浓度为40%、胺盐重结晶次数为2~3次、结晶方式为自然结晶,所制得的脱氢枞酸收率为48.59%,纯度为99.28%.并对脱氢枞酸单离过程的收率、纯度和损失率进行了跟踪分析,其中胺化反应-结晶过程脱氢枞酸产品的损失率最大,其次是溶剂萃取过程,二者损失率分别为36.12%和10.94%.     

超声波协同反应-结晶耦合单离脱氢枞酸

以歧化松香和2-乙醇胺为原料、乙醇为溶剂、超声波协同反应-结晶制备脱氢枞酸乙醇胺盐,经萃取、结晶、重结晶、酸化制得脱氢枞酸。通过正交优化实验,考察了溶剂浓度、反应温度、反应时间、超声波功率、搅拌转速对脱氢枞酸收率的影响,确定最佳单离条件为：反应时间50 min,反应温度35℃,超声波功率500 W,溶剂浓度50%,搅拌转速400 r•min^-1,在该操作条件下脱氢枞酸的收率达55.37%,纯度达99.53％。并探讨了脱氢枞酸胺化反应-结晶过程相态变化对反应平衡和选择性的影响,当反应温度分别为35℃和70℃时,胺化反应是在非均相和均相下进行,所得脱氢枞酸产品的纯度为99.53%和95.66%。采用GC、GC-MS、元素分析、UV、FT-IR、熔点仪和旋光仪对脱氢枞酸产品进行了分析鉴定,实验值与文献值吻合。     

-苯乙酯的合成

通过一种简单易操作的方法合成了脱氢枞酸月桂酯和脱氢枞酸β-苯乙酯,脱氢枞酸首先在甲苯中与SOCl₂反应制得脱氢枞酸酰氯,脱氢枞酸酰氯在室温下与月桂醇和β-苯乙醇反应制得脱氢枞酸月桂酯和脱氢枞酸β-苯乙酯。     

脱氢枞酸型成核剂制备高透明高光泽聚丙烯研究

采用脱氢枞酸型成核剂制备了高透明、高光泽聚丙烯,研究了脱氢枞酸型成核剂种类和用量对聚丙烯光学性能、力学性能、结晶形态和非等温结晶行为的影响.结果表明,脱氢枞酸型成核剂可以大幅度降低聚丙烯的雾度,提高光泽度,改善力学性能.脱氢枞酸脱氢枞酸钾脱氢枞酸钠为111(摩尔比)的共晶体(11 K1 Na)的改性效果最佳,当其用量为0.3%时,PP的雾度下降了80%,达到7.2%,光泽度提高了35%,达到134.1%,同时具有较好的力学性能.脱氢枞酸型成核剂的加入可以极大地减小聚丙烯球晶的尺寸,特别是11K1Na共晶体,经0.3%的11K1Na共晶体成核改性之后,聚丙烯球晶粒径小于1μm.脱氢枞酸型成核剂改性聚丙烯的结晶温度、熔融温度和结晶度也提高了,11K1Na共晶体的成核改性效率最高.     

季戊四醇双甲基膦酸酯的热分解动力学

采用热重分析方法对阻燃剂季戊四醇双甲基膦酸酯的热分解行为及其动力学规律进行了研究。得到在氮气气氛升温速率分别为5、10、20、40℃/min下其TGA-DTG曲线。运用Kissinger、Flynn-Wall-Ozawa(FWO)和atava-esták法对其热分解动力学进行了研究,计算出其热分解反应的表观活化能为97.32 k J·mol-1;指前因子的对数值lg A为8.30;其热分解机理为一维相界面反应,热分解动力学机理函数的积分式G(α)=α。     

Pd/C上松脂催化歧化反应的研究

以Pd/C为催化剂、马尾松和湿地松松脂为原料并利用其自身所含松节油作溶剂进行催化歧化反应制备歧化松香和对-伞花烃的研究.采用GC-MS和GC法定性定量分析了松脂催化歧化反应产物,并探讨了松脂歧化反应的竞争机制,发现酸性物与中性油的分子间氢转移反应均以脱氢反应为主,主产物为脱氢枞酸和对-伞花烃,伴随少量加氢反应.考察了搅拌速度对外扩散的影响,表明当搅拌转速大于500 r·min-1时,即可消除外扩散对反应速度的影响.由均匀实验设计方法确定了Pd/C上马尾松松脂催化歧化反应的最佳工艺条件为:反应温度260℃,催化剂用量为占松脂质量的 0.2%,反应时间为 180 min,该条件下脱氢枞酸含量(占酸性物的重量百分数)和对-伞花烃含量(占中性油的重量百分数)分别为 89.45%、61.76%,所得产品优于ZB B72002-1984 的特级歧化松香指标.比较了马尾松松脂与湿地松松脂催化歧化反应的效果,在相同反应条件下以马尾松松脂为原料制得的脱氢枞酸比以湿地松松脂为原料制得歧化产品中脱氢枞酸的含量高18%、对-伞花烃含量高16%.     

Sapindaceae,cyanolipids, and bugs

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.     

2008～2009年世界塑料工业进展

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。     

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.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

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.     

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.