微波辐射下阳离子交换树脂催化合成对硝基苯甲酸乙酯

以对硝基苯甲酸和乙醇为原料,H-732强酸性阳离子交换树脂为催化剂,在微波辐射条件下合成对硝基苯甲酸乙酯,探讨了微波功率、醇酸摩尔比、催化剂用量、反应时间对产品产率的影响。结果表明,H-732强酸性阳离子交换树脂在微波辐射条件下对酯化反应有良好的催化能力;醇酸摩尔比为3∶1,催化剂用量为对硝基苯甲酸质量的20%,反应时间15 min,微波功率为250 W时,对硝基苯甲酸乙酯的产率最高为87.45%,催化剂可以重复使用,再生后催化性能保持良好。     

高压微波催化合成对硝基苯甲酸乙酯

以一水合硫酸氢钠为催化剂，利用高压微波技术，快速合成了对硝基苯甲酸乙酯。用正交试验研究了各反应因素对产品收率的影响，确定最佳反应条件为：以2．0g对硝基苯甲酸为准，醇酸物质的量比为4：1，催化剂用量为1．0g，微波时间为9min，微波功率为522w，产率达97．8％。     

微波辐射磷钨酸催化合成对硝基苯甲酸乙酯

利用磷钨酸作催化剂,对硝基苯甲酸和乙醇作原料,在微波辐射下合成对硝基苯甲酸乙酯。研究了微波时间、醇酸物质的量比、催化剂用量和微波辐射功率对产率的影响。在单因素实验基础上,固定微波功率240W,采用响应面法优化了合成工艺参数,根据实际条件修正实验参数:微波时间12min、醇酸比4.7∶1、催化剂用量3.2%,进行三次实验产率平均值达86.2%。     

硅胶负载H_6PMo_9V_3O_(40)催化制备5-硝基水杨酸甲酯

采用硅胶负载Keggin型H6PMo9V3O40催化水杨酸甲酯与硝酸反应制备5-硝基水杨酸甲酯,考察了反应时间、反应温度、催化剂用量、硝酸用量对反应的影响。较佳的反应条件为:四氯化碳为溶剂,m(水杨酸甲酯)∶m(质量分数65%硝酸)∶m(催化剂)=3.04∶3.00∶3.00,45℃反应3 h,5-硝基水杨酸甲酯的产率81.5%,3-硝基水杨酸甲酯的产率12.4%,总产率93.9%;催化剂回收容易,且重复使用5次后,活性基本不变。     

苯磺酸催化合成对硝基苯甲酸乙酯

以苯磺酸为催化剂 ,实现了对硝基苯甲酸与乙醇反应合成对硝基苯甲酸乙酯。最佳反应条件 :以 0 .0 2 5 mol对硝基苯甲酸为准 ,n(对硝基苯甲酸 )∶ n(乙醇 ) =1∶ 4,催化剂用量为 1 .2 g反应 4h,反应温度 78～ 82°C,产率达 98.6 %。     

硝酸氧化法生产对硝基苯甲酸的工艺探讨

本文探讨了用硝酸氧化对硝基甲苯生产对硝基苯甲酸的工艺过程，反应温度、硝酸浓度、母液回用等对产品质量的影响，在2m^3反应釜中，当投料量为200kg，反应时间3小时时，控制反应温度在180～192℃（压力1.8～1.9MPa）、硝酸浓度为40%，成品对硝基苯甲酸的色泽黄白，Fe^3 含量低，纯度高，符合公司内部质量标准。     

增塑剂对硝基苯甲酸异辛酯合成新工艺

以对硝基苯甲酸和异辛醇为原料,采用颗粒状活性炭固载对甲苯磺酸作催化剂合成对硝基苯甲酸异辛酯,设计了四因素、三水平的正交实验,考察了影响反应的各种因素。实验结果表明,酯化反应的最佳条件:对硝基苯甲酸∶异辛醇=1∶2、催化剂用量为反应物酸质量的1.0%、回流温度、反应时间6 h,反应原料酸质量为0.10 mol时,带水剂甲苯40 mL,产率可达95.5%。     

钛酸四丁酯催化合成硝基卡因的研究

对硝基苯甲酸和N，N-二乙基乙醇胺在二甲苯溶液中，以直接酯化法合成硝基卡因。通过对催化剂种类、催化剂用量、反应时间等影响因素的考察，确定以钛酸四丁酯作为催化剂，催化剂用量为对硝基苯甲酸质量的3．5％，n(对硝基苯甲酸)：n(N，N-二乙基乙醇胺)=1：1，反应14h。硝基卡因的产率达到82．1％，比没有催化剂时产率提高11．8％。     

微波辐射相转移催化法合成对硝基苯甲酸

采用微波辐射方法,以对硝基甲苯和高锰酸钾为原料,水作溶剂,在相转移催化剂四丁基溴化铵存在下合成对硝基苯甲酸。当微波功率800W,微波辐射时间15min,相转移催化剂用量为对硝基甲苯5%(摩尔分数),氧化剂KMn O4和对硝基甲苯的物质的量比为2.2时,对硝基苯甲酸收率为72.95%。产品结构经红外表征。实验表明四丁基溴化铵对高锰酸钾氧化对硝基甲苯制备对硝基苯甲酸是一种优良的相转移催化剂。     

微波法强酸性树脂催化合成对羟基苯甲酸酯

采用强酸性阳离子交换树脂为催化剂,以对羟基苯甲酸和脂肪醇为原料,在微波辐射下合成了8种C2～8烷基对羟基苯甲酸酯。探讨了微波功率、微波辐射时间、催化剂用量、醇酸摩尔比等对合成对羟基苯甲酸丁酯产率的影响。结果表明,微波功率320 W、微波辐射30 min、醇酸摩尔比8∶1、强酸性阳离子交换树脂0.6 g,在无带水剂存在下,对羟基苯甲酸丁酯的产率可达90.3%。同时考察了催化剂的重复使用性。     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.