室温离子液体[bmim]BeS的萃取脱硫性能

选择水溶性的离子液体[bmim]BeS作萃取剂,对模拟油品中的4种含硫有机物噻吩、2-甲基噻吩、苯并噻吩、二苯并噻吩进行了萃取,确定了适宜的萃取操作条件。实验结果表明,[bmin]BeS对含硫化合物的萃取平衡时间只需3 min;适宜的操作温度为40～50℃。在室温下以溶剂比为1∶1对模拟体系进行4级错流萃取,脱硫率可以达到60%～90%。     

一种低共熔溶剂在深度萃取模拟油脱硫中的应用

以咪唑及其衍生物和Bu4NBr为原料,按不同原料配比,通过低温共熔得到了一系列新型低共熔溶剂(DESs),用于萃取脱除模拟油品中的二苯并噻吩(DBT),并对其最佳脱硫条件进行了考察。结果表明:当n(Bu4NBr)/n(咪唑)=0.6时,该类DESs对二苯并噻吩表现出最佳萃取效果。针对DESs考察了剂油体积比与反应温度对脱硫效果的影响,测定了DESs的选择性能与重复使用性能。结果表明:在V(DES)∶V(Oil)=1∶6、萃取温度为20℃、萃取时间为30 min时,咪唑与Bu4NBr共熔物(DESⅠ)对二苯并噻吩的脱硫率达到89.2%;经4次萃取后,其脱硫率达到95.0%;相同条件下该类DESs对于不同噻吩类衍生物的脱除能力的顺序为:二苯并噻吩(DBT)苯并噻吩(BT)4,6-二甲基二苯并噻吩(4,6-DMDBT)噻吩(T);再生后脱硫效果良好;经7次重复萃取过程后,DESs对DBT的脱硫率仍高达86.8%。     

氮化碳辅助超声氧化脱除模拟油硫化物

通过高温煅烧三聚氰胺的方法制备氮化碳。以氮化碳,甲酸为催化剂、过氧化氢为氧化剂、DMF为萃取剂超声氧化萃取脱除模拟油中的二苯并噻吩(DBT)。考察了反应温度、反应时间、氧化剂加入量、催化剂加入等因素对脱硫率的影响。结果表明,当模拟油:双氧水:甲酸的体积比为100∶3∶6、氮化碳为0.03 g、反应温度为50℃、反应时间为20 min、萃取剂DMF剂油比为0.25∶1时,二苯并噻吩的脱除率可以达到82.2%。催化剂重复使用3次后,脱硫率仍然保持在75%。     

离子液体脱除汽油中含硫化合物的研究

Brφnsted酸性吡咯烷酮离子液体N-甲基-2-吡咯烷酮氟硼酸盐([Hnmp]BF4)为萃取剂和催化剂,质量分数30%双氧水为氧化剂,将萃取脱硫和氧化脱硫相结合,对含有噻吩的模型油和FCC汽油进行萃取氧化脱硫研究。考察了氧与硫摩尔比、温度等对脱硫率的影响。结果表明:[Hnmp]BF4既是萃取剂又是催化剂,与H2O2作用产生的羟基自由基能将模型油中的噻吩和FCC汽油中的含硫化合物氧化,离子液体再生4次后脱硫性能开始下降,汽油的脱硫率达到82.7%。     

催化裂化汽油氧化-萃取脱硫

采用催化裂化(FCC)汽油氧化-萃取深度脱硫工艺,考察了氧化反应条件、萃取剂的种类、萃取剂中的含水量以及剂油比对萃取脱硫效果的影响,并对氧化-萃取前后硫含量及类型硫进行了分析。结果表明:杂多酸/相转移剂/H2O2催化氧化体系是非常有效的氧化脱硫体系;随着油剂比、萃取剂含水量的增加,汽油的脱硫率下降,收率增加,在剂油比1∶1、溶剂的含水量10%条件下,汽油的脱硫率达到80%以上,收率97.5%以上;杂多酸/相转移剂/H2O2催化氧化体系对噻吩环被破坏电子效应强的苯并噻吩及甲基苯并噻吩类硫化合物有很好的反应活性,对电子效应弱的噻吩类硫化合物反应活性较低。     

酸性离子液体脱除柴油中碱性氮化物

合成离子液体N-甲基吡咯烷酮磷酸二氢盐([Hnmp]H_2PO_4),用吡啶红外探针法测定其酸性。采用500μg/g的喹啉模型油考察其对油品中碱性氮化物的脱除性能。结果表明,在剂油质量比1∶7,反应温度为30℃,反应时间为30 min,静置时间120 min的条件下,模型油中碱性氮化物的脱除率可达到98.64%。在离子液体[Hnmp]H_2PO_4回收利用4次后,碱氮脱除率仍在96%以上。同时该离子液体也能有效脱除碱氮含量高达0.52%(质量分数)的抚顺页岩油柴油馏分中的氮化物,当剂油质量比为1∶1时,柴油馏分的碱氮脱除率可达94.25%。     

酸性离子液体脱除柴油中碱性氮化物

合成离子液体N-甲基吡咯烷酮磷酸二氢盐([Hnmp]H_2PO_4),用吡啶红外探针法测定其酸性。采用500μg/g的喹啉模型油考察其对油品中碱性氮化物的脱除性能。结果表明,在剂油质量比1∶7,反应温度为30℃,反应时间为30 min,静置时间120 min的条件下,模型油中碱性氮化物的脱除率可达到98.64%。在离子液体[Hnmp]H_2PO_4回收利用4次后,碱氮脱除率仍在96%以上。同时该离子液体也能有效脱除碱氮含量高达0.52%(质量分数)的抚顺页岩油柴油馏分中的氮化物,当剂油质量比为1∶1时,柴油馏分的碱氮脱除率可达94.25%。     

中孔硅胶负载浓硝酸脱除柴油中的硫化物

采取中孔硅胶负载浓硝酸脱除1 000×10~(-6)的4,6-二甲基二苯并噻吩模型柴油中的硫化物,考察反应温度、酸负载量、剂油质量比和吸附剂目数对脱硫效果的影响,并通过红外光谱分析和N_2等温吸附法对硅胶进行表征。结果表明,中孔硅胶具有较大的比表面积、孔体积和合适的孔径;浓硝酸可以负载于中孔硅胶上并将4,6-二甲基二苯并噻吩氧化为砜后吸附在硅胶上。在反应温度45℃、(40~60)目硅胶和硅胶与浓硝酸质量比为1∶0.75条件下脱硫效果最好,剂油质量比为1∶7.5时,脱硫率达93.7%,脱硫后的模型柴油硫含量达到国Ⅴ标准。     

EMIES/nC_9H_(10)O_2基低共熔溶剂的制备及其氧化脱硫活性的研究

通过简单加热1-乙基-3-甲基咪唑硫酸乙酯(EMIES)离子液体和3-苯丙酸(C_9H_(10)O_2)的混合物,制备了一系列酸性低共熔溶剂EMIES/nC_9H_(10)O_2(n=0.25,0.5,1,2,4)。通过FTIR,~1H NMR和TGA的表征,确定EMIES/nC_9H_(10)O_2的结构。以该低共熔溶剂为催化剂和萃取剂,H_2O_2为氧化剂,组成氧化-萃取脱硫体系,用于脱除模拟油中的硫化物。考察了原料配比、反应温度、氧硫比(O/S)、低共熔溶剂加入量和不同硫化物对脱硫性能的影响。结果表明,在EMIES和C_9H_(10)O_2摩尔比为1∶1,反应温度为50℃,O/S比为8,低共熔溶剂加入量为1.5 g和模拟油5 ml的反应条件下,二苯并噻吩、4,6-二甲基二苯并噻吩和苯并噻吩的脱除率分别为94.8%、91.6%和46.4%。低共熔溶剂可循环使用6次,活性无明显下降。此外,对该氧化-萃取脱硫体系的脱硫机理进行了探讨。     

[Cnmim]Br/FeCl3型离子液体萃取脱除二苯并噻吩

合成了6种咪唑型离子液体[C_3-8mim]Br/FeCl₃,采用红外光谱和拉曼光谱对其进行表征,并考察了离子液体对二苯并噻吩的萃取脱除效果。结果发现,[C₃mim]Br/FeCl₃的萃取脱硫效果最佳,升高温度和增大剂油比均有利于脱硫率的提高,剂油比1:1(体积比)时,萃取时间达到12 min就可使脱硫率高达92%。且萃取反应完成后,离子液体不做处理继续重复使用,重复使用5次,脱硫率可以达到60%。     

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.     

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.     

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.     

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.     

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.     

Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process

A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by ¹H MAS NMR. For direct comparison purposes, an SiO₂ coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N₂ absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.