超临界CO2萃取柑橘精油的工艺研究

以柑橘皮为实验材料,以柑橘精油萃取率为指标,用超临界二氧化碳萃取方法,在萃取温度、萃取压力、萃取时间、投料量试验的基础上,经正交试验对柑橘皮中精油的萃取工艺条件进行了优化。研究发现柑橘皮中精油超临界二氧化碳萃取的最佳萃取工艺条件为压力30 MPa,温度32℃,投料量120 g,萃取时间2.5 h,柑橘精油的萃取率为3.60%。     

从沙田柚皮中提取精油的工艺研究

为了综合利用沙田柚皮，进行了从沙田柚果皮提取精油的研究，通过实验筛选，得到了柚皮精油提取的最佳工艺条件：采用石油醚为提取溶剂，m(石油醚)：m(柚皮)=24：1，回流提取两次，每次提取60min。提取液进行真空浓缩，得精油粗产品。往精油粗产晶中加入乙醇溶解．放入-5℃冰箱中冷冻过夜，抽滤，滤液进行真空浓缩，即得精油，产率约1．96％。φ(精油)=99．2％。实验得到的柚皮精油为独特柚子香味的黄色油状液体，难溶于水，易溶于乙醇等有机溶剂，物理参数为：相对密度d20^20=0．857，旋光度为a= 97。折光率n=14765.     

响应面法优化香茅精油超临界CO2萃取工艺

以萃取温度、萃取压力、萃取时间为考察因素,以香茅精油收率为考察指标,采用单因素实验和响应面法对超临界CO_2萃取香茅精油的工艺条件进行优化。确定超临界CO_2萃取香茅精油的最优工艺条件为:萃取温度39℃、萃取压力26 MPa、萃取时间88 min,在此条件下,香茅精油的平均收率达到3.95%。     

响应面法优化椪柑果皮精油提取新技术工艺研究

以靖安椪柑鲜果皮为原料,采用超声——微波协同萃取--有机溶剂相结合的集成技术提取果皮精油。考察了提取时间、提取温度及料液比对椪柑鲜果皮精油得率的影响,并采用响应面法建立了精油得率与提取时间、提取温度及料液比之间的关系,得到了最佳提取工艺条件：提取时间12.0min,提取温度为50.5℃、料液比为8.2：1（ml：g）。...     

超临界CO_2萃取烟草精油的工艺研究

以烟草为材料,以精油提取率、新植二烯提取率、精油品质为评价指标,通过单因素实验考察夹带剂乙醇的体积分数、夹带剂流量、萃取压力、萃取温度、CO2流量、萃取时间等因素对萃取效果的影响。在此基础上,通过正交实验优选萃取工艺条件为:94%乙醇为夹带剂、夹带剂流量0.04mL·min-1、萃取压力25MPa、萃取温度50℃、CO2流量2.0L·min-1、萃取时间3.0h,在此条件下萃取的精油金黄透亮,夹带剂残留少,精油提取率为37.58mg·g-1,新植二烯提取率为4.045mg·g-1。     

微波辅助萃取洋葱精油的研究

本实验以精油产率为评价指标,进行了洋葱精油的微波辅助萃取工艺研究,考察了萃取溶剂种类、温浸时间、萃取温度、萃取时间和料液比对精油产率的影响,并在单因素考察基础上,通过正交实验设计得出优化工艺条件。结果表明,在以二氯甲烷为萃取溶剂,萃取温度25℃,萃取时间45s,酶解时间1.5小时,料液比1∶5的条件下可得到最优工艺条件。与传统的溶剂浸提法、索氏提取法相比较,微波辅助提取具有提取时间短、效率高、节约能源、产品质量高、原料利用率高、无污染等优点,并且明显提高了洋葱油中二丙基二硫醚组分的含量。     

超临界CO2萃取黑胡椒中有效成分的研究

用超临界CO2萃取技术,首先在低压、低温的条件下选择性萃取黑胡椒精油,进而在高温、高压及极性夹带剂的协同作用下,萃取富含胡椒碱的黑胡椒油树脂。另外,利用分子蒸馏技术纯化超临界CO2萃取的黑胡椒精油,得到适用于日化行业的无色、无辛辣感的挥发油,并通过GC-MS对比分析其香气成分。研究结果表明,超临界CO2萃取黑胡椒精油的较优条件为:萃取压力10MPa、萃取温度35℃、萃取时间1.5h,在该条件下产物得率为3.01%;超临界CO2萃取黑胡椒油树脂的最佳条件为:m(原料)∶m(体积分数95%食用乙醇)=2∶1、萃取压力30MPa、萃取温度50℃、萃取时间4h,在该条件下油树脂得率为7.88%,油树脂中胡椒碱质量分数为65.79%。     

超临界CO2萃取与水蒸汽减压蒸馏萃取柑桔皮精油比较

使用超临界CO2萃取法和水蒸汽减压蒸馏萃取柑桔皮精油,两种方法精油收率相当,最高收率均为1.2%。但水蒸汽减压蒸馏法提取的精油质量好,为浅黄色流动性液体,气味具有新鲜柑桔皮的清香,流程简单,超临界CO2萃取所得产品质量差,流动性差,为深黄色半流动性液体,杂质较多。     

在玫瑰花渣中提取玫瑰精油及抗氧化性研究

研究用有机溶剂萃取玫瑰花渣中的玫瑰精油,结合气质联用(GC-MS)分析精油成分,并对萃取条件进行优化。结果表明,最优萃取剂为石油醚,料液比为1∶3,回流时间为4 h,蒸馏温度为80℃时,玫瑰精油提取率高达0.571 4%。产物中存在香茅醇、乙酸香叶酯等精油主要成分。检验玫瑰精油的抗氧化性,其清除羟基自由基能力与没食子酸相当。     

三种唇形科植物精油对水杨酸透皮促渗效果的研究

采用Franz扩散池,用猪皮模拟人皮肤对水杨酸的透皮吸收,利用紫外可见分光光度计测定水杨酸的透皮率,考察三种唇形科植物精油对水杨酸的透皮促渗效果。实验结果表明：在水杨酸透皮时间为24 h、精油含量为4%的最佳实验条件下,罗勒精油、百里香精油及迷迭香精油的水杨酸透皮率分别为1.200%、1.159%、0.993%,而空白对照组水杨酸的透皮率仅为0.373%,表明三种唇形科植物精油对水杨酸均具有良好的透皮促渗效果。     

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。     

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.     

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.     

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.