水中水合肼还原芳香族硝基化合物的研究

以NaOH溶液沉淀FeCl3溶液制备了催化剂FeO(OH)。在水中用FeO(OH)催化水合肼还原9种芳香族硝基化合物得到相应的芳胺,收率96%-99%。并以邻硝基甲苯为反应底物考察了水合肼用量、催化剂用量、反应温度和反应时间对产物收率的影响。较优的反应条件为:n(水合肼)∶n(邻硝基甲苯)=2∶1;催化剂FeO(OH)的用量为0.015 g/mmol邻硝基甲苯,80℃反应50 min,邻甲苯胺的收率达98%。     

水中CuO-Al_2O_3催化水合肼还原芳香族硝基化合物

以NaOH溶液快速沉淀CuC l2和A lC l3的混合溶液制备了催化剂CuO-A l2O3,当n(CuO)∶n(A l2O3)=1∶2时所得催化剂性能最好。在水中,以邻硝基甲苯为底物,考察了几种因素对反应的影响。较优的反应条件为:4.11 g(30 mmol)邻硝基甲苯,3.53 g(60 mmol)水合肼,0.45 g CuO-A l2O3,80℃反应50 m in。在此条件下邻甲基苯胺的收率达到98%。在同样的条件下,CuO-A l2O3催化水合肼,几种还原芳香族硝基化合物得到相应的芳胺,收率90%~99%。     

2-甲基-4-甲氧基苯胺的合成研究

以邻硝基甲苯为底物,Pt/C为催化剂,在甲醇、乙酸和硫酸混合溶液中经催化加氢还原和Bamberger重排一锅法生成2-甲基-4-甲氧基苯胺(MMA)。考察了不同酸种类、酸的用量等对催化加氢反应的影响,同时对催化剂结构进行了表征。结果表明:在反应温度60℃,氢气压力0.3 MPa,5%的Pt/C催化剂的用量为邻硝基甲苯的1.8%(质量比),n(硫酸)∶n(邻硝基甲苯)=2∶1,n(乙酸)∶n(邻硝基甲苯)=0.5∶1,反应时间4 h下,邻硝基甲苯转化率可达100%,2-甲基-4-甲氧基苯胺的选择性达到69.8%。     

温和条件下2-[苯基(苯胺基)甲基]环己酮的一锅法催化合成

分别采用SnCl4.5H2O、对甲苯磺酸、NaHSO4.H2O和KHSO4催化苯胺、苯甲醛和环己酮的Mannich缩合反应一锅法合成了2-[苯基(苯胺基)甲基]环己酮(PPMC)。系统考察了原料配比n(环己酮)∶n(苯胺)及n(苯甲醛)∶n(苯胺)、催化剂用量、反应温度和反应时间对PPMC收率的影响,并就四种催化剂催化性能进行了比较。实验结果表明,适宜反应条件为n(苯甲醛)∶n(苯胺)∶n(环己酮)=1∶1∶1.2,催化剂用量为反应物总质量的3.36%～13.45%,反应温度15～25℃,反应时间1～4h,PPMC收率为77.4%～84.2%。其中SnCl4.5H2O和对甲苯磺酸具有较理想的催化活性,催化剂用量少,反应时间短,收率高。该合成工艺路线简捷,催化剂价廉易得,使用方便,反应条件温和,收率可观。     

由3-氟-4硝基甲苯两步合成1,2,6-三取代苯并咪唑

以3-氟-4-硝基甲苯为初始原料,先借助微波合成N-取代-2-硝基-4-甲基苯胺,其与不同的醛反应合成了1,2,6-三取代苯并咪唑。从反应温度、投料比两方面对第一步的取代反应进行了反应条件优化,确定了最佳反应条件:反应温度为83℃,投料比为n(3-氟-4-硝基甲苯)∶n(苯乙胺)∶n(K_2CO_3)=1.0∶1.5∶1.8,此时5-甲基-2-硝基-N-苯乙基苯胺(Ⅱa)产率为99.2%,5-甲基-2-硝基-N-(3-苯基丙基)苯胺(Ⅱb)产率为98.9%。从催化剂的用量、反应温度两方面对第二步反应进行了反应条件优化,确定了最佳反应条件:乙醇为溶剂、5-甲基-2-硝基-N-苯乙基苯胺(2 mmol)、醛(2 mmol)、1 mol/L的Na_2S_2O_4水溶液18 m L,反应时间40~120 min,此时2-(4-氯苯基)-6-甲基-1-苯乙基-苯并咪唑(Ⅲb)收率为91.3%。与文献中报道的反应时间12 h相比,反应时间大大缩短。在该条件下合成10种1,2,6-三取代苯并咪唑,9种为新化合物,产物结构经IR、~1HNMR和~(13)CNMR进行了确证。     

复合固体超强酸SO42-/Fe2O3/Al2O3/ZnO的制备及其催化性能的研究

利用共沉淀法由Fe(NO3)3、Al(NO3)3、Zn(Ac)2和H2SO4制备了SO42-/Fe2O3/Al2O3/ZnO催化剂,并用于催化合成苯甲醛丙二醇缩醛,研究了醛醇摩尔比、催化剂用量、反应时间等因素对产品收率的影响。结果表明,在n(苯甲醛)∶n(丙二醇)=1∶1.2,催化剂用量为反应物总质量的1%,反应时间50 min的最佳条件下,苯甲醛丙二醇缩醛的收率可达97.6%。     

3-(2-甲基-6-甲基硫代苯基)-4,5-二氢化异噁唑的合成研究

以2-(4,5-二氢异噁唑-3-基)-3-甲基苯胺为原料,铜为催化剂在无水的条件下经亚硝酸叔丁酯重氮化合成3-(2-甲基-6-甲基硫代苯基)-4,5-二氢化异噁唑。探索了反应温度、反应时间、催化剂的用量等因素对反应的影响,优化条件为反应温度为60℃,反应时间为1.5 h,n(2-(4,5-二氢异噁唑-3-基)-3-甲基苯胺)∶n(催化剂)=1∶3,反应收率为98.6%,产品结构经LC-MS、~1H NMR确证。     

相转移催化合成邻乙氧基苯酚技术研究

研究了以聚乙二醇(PEG-400)作为相转移催化剂,由邻苯二酚(C6H6O2)与溴乙烷(C2H5Br)为主要原料合成邻乙氧基苯酚(C8H10O2)工艺。以邻乙氧基苯酚的收率为考察指标,考察了反应温度、反应时间、原料物质的量比和催化剂用量(以邻苯二酚的质量为计算依据)等对反应收率的影响,通过正交实验以及单因素实验,建立PEG相转移催化条件下合成邻乙氧基苯酚的适宜工艺条件即:n(C6H6O2)∶n(NaOH)∶n(C2H5Br)=1∶1.2∶1.2,反应温度为68℃,反应时间为6 h,催化剂用量为2%;该反应条件下,产品邻乙氧基苯酚收率65%。以PEG-400为相转移催化剂合成邻乙氧基苯酚的方法工艺成本低、污染小、操作简单易行,适应于工业化生产。     

尿素和苯酚直接合成水杨酰胺

以CaO、MgO、La2O3、Al2O3、ZrO2等5种金属氧化物为催化剂,以尿素和苯酚为原料直接合成了水杨酰胺。在相同条件下,发现MgO对该反应的催化性能最佳。考察了反应温度、反应时间、催化剂用量、原料配比等因素对水杨酰胺收率的影响,最佳反应条件为:反应温度245℃,反应时间12h,MgO的用量0.2g,n(苯酚)∶n(尿素)=15∶1,水杨酰胺的收率达45.1%。     

复合固体超强酸SO_4~(2-)/Fe_2O_3/Al_2O_3/ZnO/ZrO_2催化剂的制备及其催化性能

沉淀法由Fe(NO3)3、Al(NO3)3、Zn(Ac)2、ZrOCl2和H2SO4制备SO2-4/Fe2O3/Al2O3/ZnO/ZrO2催化剂,用于催化合成苯乙酮乙二醇缩酮,研究了醇酮摩尔比、反应时间、带水剂用量、催化剂用量等对产品收率的影响。结果表明,在n(苯乙酮)∶n(乙二醇)=1∶1.2,苯乙酮物质的量为0.2 mol,催化剂的量是反应物料总质量的1.5%,带水剂甲苯20 mL,100~120℃回流反应60 min的条件下,苯乙酮乙二醇缩酮的收率达98.8%。     

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.