采用HTLcs前驱体制备的丙酮一步法制MIBK催化剂

采用共沉淀法制备Cu Mg A1三元类水滑石,进而煅烧得到CuO MgO Al2O3催化剂用于丙酮加氢一步合成甲基异丁基酮(MIBK)反应。研究了催化剂活性组分配比及反应条件对转化率和选择性的影响,经筛选得到催化剂体系的最佳组成为:n(Cu)∶n(Mg)∶n(Al)=4∶16∶10,适宜的反应条件为:温度240℃,n(H2)∶n(丙酮)=2.5,液空速为4.8mL/h·g,在该条件下丙酮转化率达73.88%,MIBK选择性达55.23%。     

黄陵煤矸石制备4A分子筛的研究

黄陵煤矸石的灰成分以SiO2、Al2O3为主,这些组分正是合成分子筛的原料.将煤矸石经过煅烧活化、酸浸除铁、碱熔预处理后,采用水热合成的方法制备4A分子筛.通过正交试验考察了n(Na2O)∶n(SiO2)、n(H2O)∶n(Na2O)、老化时间、晶化温度、晶化时间5个因素对分子筛钙离子交换性能的影响,实验结果表明:n(Na2O)∶n(SiO2)是对4A沸石钙离子交换量影响最大的因素,其次是晶化温度,最小的为老化时间;且在n(Na2O)∶ n(SiO2)为1.3,n(H2O)∶ n(Na2O)为45,老化时间8h,晶化时间4h,晶化温度85℃下制备所得4A分子筛的钙离子交换量达到296.84 mg CaCO3/g干沸石.自制分子筛的XRD及SEM检测分析表明,最优条件下制备出的4A分子筛晶型完整,轮廓清晰,呈立方体,颗粒大小均匀,在1～2 μm左右.     

氧化铋超细粉体制备过程热分析研究

以硝酸铋为反应原料,利用尿素为沉淀剂,采用均匀沉淀法制备了Bi2O3超细粉体。利用TG-DSC及XRD 对所制备的Bi2O3超细粉体进行了表征。研究结果表明,尿素均匀沉淀法合成的前驱体成分主要为(BiO)2(CO3)3、Bi(OH)3 和BiOOH的混合物,确定最佳煅烧温度范围为560℃-620℃。XRD分析结果表明:均匀沉淀法制备得到单斜晶型α- Bi2O3,且纯度高。     

固相反应法制备铌酸铁光催化剂降解甲基橙

以Fe3O4和Nb2O5为原料,采用固相反应法制备铌酸铁光催化剂,评价了其光催化降解甲基橙的活性。研究了n(Fe)∶n(Nb)、煅烧温度、光催化剂质量浓度和光催化反应时间对光催化降解率的影响。700℃以下的煅烧产物中生成了FeNb2O6,800℃以上的煅烧产物中生成了FeNbO4。将n(Fe)∶n(Nb)为0.8的Fe3O4和Nb2O5在700℃煅烧8h可以制备出活性最佳的铌酸铁光催化剂。NiO的掺杂不能提高铌酸铁的光催化能力。当ρ(甲基橙)为10mg/L,ρ(光催化剂)为4g/L时,光催化降解效率最大,光照时间为180min时,甲基橙的η(降解率)为72.7%。     

γ-Al_2O_3催化肉桂醛氧化制苯甲醛研究

以Na Al O2制备了γ-Al_2O_3并考察了其催化肉桂醛氧化制苯甲醛的活性。结果表明,γ-Al_2O_3的制备过程中,最佳煅烧温度为400℃,煅烧时间为2h。反应中m_(肉桂醛)∶m_(γ-Al2O3)的最佳配比为0.1982∶1,最佳反应温度为40℃,反应时间为60min。以乙醚为洗涤剂,考察了γ-Al_2O_3的稳定性,结果表明γ-Al_2O_3的稳定性不高。     

煅烧温度对熔盐法制备硼酸铝晶须的影响

硼酸铝晶须具有密度低、拉伸强度高、热膨胀系数低、耐蚀性优异以及成本低廉等优点,是一种优良的增强材料。以Al(NO3)3·9H2O、H3BO3为原料,Na2SO4为助熔剂,采用熔盐法制备硼酸铝晶须。利用XRD、SEM和TG-DSC研究煅烧温度对产物物相、形貌以及生长过程的影响。结果表明,在煅烧温度为1100℃、煅烧时间为5h、n(Al)∶n(B)=5∶2、n(Al+B)∶n(Na)=5∶12的条件下,可合成直径约0.7μm、长度约8.7μm的Al18B4O33晶须。相同煅烧温度下,n(Al+B)∶n(Na)=5∶12时制得的晶须明显优于n(Al+B)∶n(Na)=5∶8时制得的晶须。     

无铅导电银浆的制备及其烧结工艺的研究

采用熔融冷却法制备了Bi2O3-SiO2-B2O3-ZnO系无铅低熔玻璃粉,固定浆料配比及制备工艺,将无铅玻璃粉、自制银粉和有机载体混合,经三辊碾磨机轧制成无铅导电银浆料。银浆料通过丝网印刷法印刷在玻璃基体上,在指定温度下保温烧结。采用XRD、DTA和SEM等手段分析了成分变化对无铅低熔玻璃粉软化温度和析晶温度的影响;采用差热分析法(TG、DTA)、SEM、四探针法、焊接法等研究了烧结温度和保温时间对烧成银膜导电性和附着力的影响。结果表明:无铅低熔玻璃粉中n(Bi3+)∶n(Si4+)∶n(B3+)∶n(Zn2+)=40∶20∶30∶10,银浆料的最佳烧结温度为700℃,最佳保温时间为15 min。     

镍镁铝复合金属氧化物催化剂制备生物柴油

采用共沉淀法先制备镍镁铝类水滑石化合物,以其为前驱体经400℃煅烧后制得镍镁铝复合金属氧化物催化剂。研究了过渡金属含量、n(甲醇)∶n(大豆油)和反应温度对生物柴油转化率的影响。当n(Ni 2+)∶n(Mg2+)∶n(Al 3+)=0.64∶2.36∶1时,转化率最高,可达到92.8%。而n(甲醇)∶n(大豆油)=10∶1,w(催化剂)=4%,反应温度为65℃,反应时间4h是所得的最佳操作条件。研究出的镍镁铝复合金属氧化物可作为多相催化剂,具有生产生物柴油的潜力。     

原位沉析法制备壳聚糖磁性絮凝剂及其性能研究

以壳聚糖(CS)为基材,通过原位沉析法将其与磁性Fe3O4复合制备出CS/Fe3O4磁性絮凝剂。通过单因素实验,研究了n(CS)∶n(Fe3O4)、n(Fe2+)∶n(Fe3+)、反应温度、反应时间对CS/Fe3O4絮凝效果的影响。在制备条件为n(CS)∶n(Fe3O4)=8∶1、n(Fe2+)∶n(Fe3+)=3∶3、反应温度45℃、反应时间10 min时,所得CS/Fe3O4絮凝剂对高岭土悬浮液(245～255 NTU)的浊度去除率达到97%。     

固体碱催化大豆油制备生物柴油

以Na2Si O3·9H2O为原料制备固体碱催化剂,大豆油和甲醇酯交换反应为模型,优化固体碱焙烧条件。再以最优条件制备的Na2Si O3·9H2O固体碱催化剂优化大豆油和甲醇酯交换工艺。结果表明:硅酸钠固体碱最佳制备条件为煅烧温度400℃、煅烧时间1 h。大豆油和甲醇酯交换反应优化工艺为:反应温度65℃、醇油摩尔比6∶1、反应时间2 h。     

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.