用KF／Al2O3催化合成肉桂酸的研究

采用KF/Al2O3催化剂催化合成肉桂酸，用新催化剂催化反应可以降低反应温度。缩短反应时间。提高肉桂酸的产率，探索出了最佳反应条件；当反应温度控制在16℃，苯甲醛和乙酸酐的摩尔比1：3，用6.0gKF/Al2O3催化反应1.0h，得到肉桂酸的产率为85.4%。     

用KF／Al2O3催化合成肉桂酸的研究

采用KF/Al2O3催化剂催化合成肉桂酸。用新催化剂催化反应可以降低反应温度，缩短反应时间，提高肉桂酸的产率，探索出了最佳反应条件；当反应温度控制在160℃，苯甲醛和乙酸酐的摩尔比1：3，用6.0gKF/Al2O3催化反应1.0h，得到肉桂酸的产率为85.4%。     

KF/Al2O3催化菜籽油与甲醇合成生物柴油的研究

用等体积浸渍法制备了KF/Al2O3催化剂,并将其用于菜籽油与甲醇酯交换合成生物柴油的研究.考察了反应条件、优化了合成工艺,结果表明制得的KF/Al2O3催化剂在适宜的条件下合成生物柴油的产率达96.7%,同时提出了合成反应的机理.     

微波法制备的固体碱催化丁醛自缩合反应

用微波辐射法制备了负载型固体碱催化剂K2 O/γ Al2 O3 、MgO/γ Al2 O3 、KF/γ Al2 O3 、Na2 O/γ Al2 O3 、CaO/γ Al2 O3 和SrO/γ Al2 O3 ,并应用于丁醛的自缩合反应 ,其中K2 O/γ Al2 O3和KF/γ Al2 O3 的活性较好 ,1h产率分别为 5 2 5 %和 4 7 5 %。同时考察了水的浓度及溶剂对反应的影响。结果表明当水的浓度为 1 4mol/L时 ,催化剂的活性最佳 ,而丁醇作为溶剂是几种所用溶剂中最好的一种     

K2O/Al2O3固体碱催化合成肉桂酸

以K2O/Al2O3固体碱为催化剂,催化苯甲醛与醋酐反应合成了肉桂酸.探讨了催化剂用量、反应温度、反应时间、反应物配比、不同种类和不同方法制备的催化剂对产品收率的影响.结果表明,以K2O/Al2O3为催化剂的最佳反应条件为:固体碱用量5.0 g,反应时间1 h,反应温度160℃,苯甲醛0.05 mol,苯甲醛与醋酐摩尔比1:3.最佳合成条件下肉桂酸产率达65.4%.不同方法制得的催化剂以微波制备的较好.     

KF/K2CO3/γ-Al2O3催化合成肉桂酸

以苯甲醛和丙二酸为原料,KF/K2CO3/γ-Al2O3为催化剂,经Knoevenagel反应,在无溶剂条件下催化合成了肉桂酸。产品用IR、1HNMR及元素分析进行表征。考察了催化剂用量、苯甲醛与丙二酸摩尔比和反应时间对肉桂酸收率的影响。结果表明:KF/K2CO3/γ-Al2O3具有良好的催化活性,较佳工艺条件为:苯甲醛10.2 mL(10.6 g,0.1 mol),n(苯甲醛)∶n(丙二酸)=1∶1.15,催化剂KF/K2CO3/γ-Al2O3用量2.5 g(含KF4.68 mmol),反应60 min,肉桂酸的平均收率达到92%以上。     

KF／γ-Al2O3固体超强碱催化合成对甲氧基肉桂酸乙酯的研究

研究以KF/γ-Al2O3固体超强碱为催化剂,由对甲氧基苯甲醛和丙二酸二乙酯发生Knoevenagel反应,得到高收率的反式对甲氧基肉桂酸乙酯,并考察了诸因素对产率的影响,找出了最佳反应条件。     

KF/γ-A1_2O_3固体超强碱催化合成对甲氧基肉桂酸乙酯的研究

研究以KF/γ-Al2O3固体超强碱为催化剂,由对甲氧基苯甲醛和丙二酸二乙酯发生Knoevenagel反应,得到高收率的反式对甲氧基肉桂酸乙酯,并考察了诸因素对产率的影响,找出了最佳反应条件。     

KF／Al2O3催化合成α-亚异丙基环戊酮

研究了KF/Al2O3催化下丙酮与环戊酮缩合生成α-亚异丙基环戊酮。考察了催化剂用量,反应温度以及反应时间对产率的影响。最佳反应条件是反应物用量丙酮为0.275mol,环戊酮0.075mol,催化剂用量11.9g,反应时间8h,反应温度40℃,产率50%。     

甘油水蒸汽重整制氢Ni、Co、Fe催化剂的研究

采用等体积浸渍法制备了催化剂,研究了Ni/Al2O3,Fe/Al2O3,CoMo/Al2O3和NiCo/Al2O3催化剂对甘油水蒸汽重整制氢反应的催化效果,对催化剂进行BET、TPR、XRD表征,以氢产率为实验指标对催化剂进行了评价。研究结果表明,CoMo/Al2O3催化剂在温度650℃氢产率6.02。NiCo/Al2O3催化剂在温度600℃、水醇比16、液空速0.12 h-1条件下的氢产率为6.08。催化剂活性次序为NiCo/Al2O3Co-Mo/Al2O3Ni/Al2O3Fe/Al2O3。     

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.     

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.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。