硫酸高铈催化合成乙酸异丁酯

以冰醋酸、异丁醇为原料,硫酸高铈为催化剂合成乙酸异丁酯.通过正交设计法考察了催化剂用量、原料配比、带水剂用量和反应时间等因素对反应的影响.结果表明,在催化剂用量0.6g,醇酸比1:1,带水剂环己烷用量5mL,反应时间2.5h的条件下,酯化率可达96%以上.     

硫酸高铈催化合成乙酯异戊酯

以冰醋酸、异戊醇为原料,硫酸高铈为催化剂合成乙酯异戊酯,通过正交设计法考察了催化剂用量、原料配比、带水剂用量和反应时间等因素对反应的影响。结果表明:在催化剂用量0.4g,醇酸比1.2∶1,带水剂环己烷用量5mL,反应时间1h的条件下,酯化率可达97.35%。     

硫酸氢钠催化合成富马酸二异辛酯

以富马酸和异辛醇为原料,NaHSO4做催化剂,甲苯做带水剂,合成了富马酸二异辛酯.用正交实验设计方法考察了醇酸比、催化剂用量、带水剂用量、反应时间等因素对反应的影响,确定了NaHSO4催化法合成富马酸二异辛酯的最佳工艺条件为:醇酸比为5:1,催化剂用量为酸质量的2％,带水剂用量为醇用量的1/2,反应时间为4h,产率达98％.     

固体超强酸(SO_4~(2-)/ZrO_2)催化合成丙二醇甲醚醋酸酯

采用固体超强酸(SO2-4/ZrO2)催化剂,丙二醇甲醚(PM)和冰醋酸(HAc)为原料进行酯化反应合成丙二醇甲醚醋酸酯(PMA)。考察了原料配比、催化剂用量、带水剂用量、反应时间以及反应温度等因素对反应的影响。结果表明,当丙二醇甲醚与冰醋酸摩尔比为1∶1.5,催化剂用量为反应物总质量的3.6%,带水剂用量为反应物总质量的30%,反应温度为105~112℃且反应4.2h时,丙二醇甲醚醋酸酯收率可达98.84%。     

AlCl3/NaHSO4催化合成乙酸正丁酯的研究

探讨了以AlCl3/NaHSO4为复合催化剂,冰醋酸、正丁醇为原料合成乙酸正丁酯。确定了反应的优化条件:当冰醋酸用量为0.1 mol时,反应物料的投料物质的量比n(冰醋酸)∶n(正丁酯)=1∶1.7,催化剂配料物质的量比为n(AlCl3)∶n(NaHSO4)=1∶1.5,催化剂用量2 g,15 mL环己烷作带水剂,回流温度下反应时间为120 min,其酯化率达97%。     

丙二醇甲醚醋酸酯的合成研究

采用浓硫酸作催化剂,用丙二醇甲醚和冰醋酸酯化合成丙二醇甲醚醋酸酯,考察了醚和酸的比例、催化剂用量、带水剂用量与种类、反应时间和反应温度等因素对反应的影响。优惠反应条件为:冰醋酸∶丙二醇甲醚=1.3∶1(mol/mol),催化剂用量为反应液质量的1 0%,带水剂A用量为反应液质量的25%,反应温度104～110℃,反应时间3h。丙二醇甲醚醋酸酯的收率达96 5%。     

固体超强酸SO42-/TiO2催化合成苹果酸二丁酯的研究

以固体超强酸SO42-/TiO2为催化剂,以苹果酸和正丁醇为原料催化合成苹果酸二丁酯,并探讨了酸醇比、催化剂的用量、反应时间、带水剂等因素对酯化反应的影响.结果表明,酸醇比为1∶4(苹果酸0.04 mol),催化剂用量为0.80 g,带水剂用量为2 mL,反应时间为5 h时,苹果酸二丁酯的产率可达90%以上.     

硫酸氢钠催化乙酸异丙酯合成工艺的研究

本文以冰乙酸和异丙醇为原料合成乙酸异丙酯。主要考察催化剂种类、催化剂用量、醇酸物质的量比、反应时间、带水剂种类、带水剂用量对乙酸异丙酯产率的影响,确定合成乙酸异丙酯的最佳工艺条件。实验结果表明,相对于其它催化剂,硫酸氢钠催化高效且环保。乙酸异丙酯合成的最佳合成工艺条件为:反应时间为1.5 h,催化剂用量为1.5 g,醇酸物质的量比为1∶1.5,带水剂用量10 mL,此时乙酸异丙酯产率可达62.9%。     

二氧化硅负载硅钨酸催化合成丁酮乙二醇缩酮

以二氧化硅负载硅钨酸为催化剂,以丁酮和乙二醇为原料催化合成丁酮乙二醇缩酮.探讨了丁酮与乙二醇量比、催化剂用量、带水剂及反应时间对收率的影响.实验表明,在n(丁酮):n(乙二醇)=1:1.5.催化剂用量为反应物料总质量的0.8%,带水剂环己烷10mL,反应时间75min的优化条件下,丁酮乙二醇缩酮的收率可达96.08%.     

强酸性磺酸树脂催化合成柠檬醛二乙缩醛

以强酸性磺酸树脂为催化剂,柠檬醛和乙醇为原料合成柠檬醛二乙缩醛。考察了原料配比、反应时间、催化剂用量、带水剂用量和催化剂重复使用次数等因素对反应的影响,得到合成柠檬醛二乙缩醛的最优条件为:醛醇物质的量比1∶5,催化剂用量占醛质量的11%,带水剂环己烷用量10 mL,反应时间6 h,催化剂重复使用5次催化活性未见明显衰退。具有易分离、操作简单和产品质量好等特点。     

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。