基于分壁式精馏塔的甲醇-碳酸二甲酯分离新工艺研究

提出了利用分壁式萃取精馏塔分离甲醇-碳酸二甲酯共沸物的新工艺,分析并建立了分壁式萃取精馏塔的热力学等效模型,利用Aspen Plus对该塔进行模拟和参数优化。主塔理论板数为36块,侧线精馏段理论板数为5块,隔板底端在主塔第27块塔板上,原料进料在第15块板,萃取剂进料在第3块板,回流比为1.2,溶剂比为1.2,在此参数下对分壁式萃取精馏塔进行严格模拟,可得到质量分数99.58%的碳酸二甲酯和99.82%的甲醇,回收萃取剂的质量分数可达到100%。与常规萃取精馏工艺相比,再沸器热负荷降低16.01%,冷凝器热负荷降低13.47%。     

隔离壁精馏塔萃取精馏制无水叔丁醇研究

用隔离壁精馏塔萃取精馏制无水叔丁醇,在溶剂比为1.5,回流比为2∶1,叔丁醇原料进料速度为1.7 mL/min时,塔顶叔丁醇的质量分数达到99.6%;塔釜乙二醇的质量分数达到97.7%,可直接作萃取剂循环利用。用AspenPlus对该工艺和二塔萃取精馏工艺对比,结果与实验相一致,塔顶叔丁醇质量分数的相对误差为0.4%,塔釜乙二醇质量分数的相对误差1.3%。结果显示,该工艺比现有工艺省了1个塔、1个再沸器和1个冷凝器,节能27%,降低了能耗和设备投资。     

生物燃料乙醇分壁塔萃取精馏新工艺的研究

针对生物燃料乙醇生产中的"蒸馏-脱水"过程,建立基于分壁式萃取精馏塔的三塔工艺和两塔工艺,对2种工艺进行模拟计算,比较其分离效果和过程能耗。结果显示,在满足产品质量的前提下,三塔工艺比两塔工艺节约66.6%的冷凝器热负荷和77.9%的再沸器热负荷。对三塔工艺的分壁式萃取精馏塔的工艺条件进行优化,优化结果为,主塔回流比1.5,溶剂比1.0,原料进料位置为第22块板,隔板底端位置在第28块板,气相分配比为8.4。在优化工艺条件下对三塔工艺进行全流程模拟,可得到质量分数99.96%生物燃料乙醇和99.49%的水,回收萃取剂乙二醇质量分数为99.97%。     

乙醇脱水分壁式萃取精馏工艺研究

利用Aspen Plus过程模拟软件,采用乙二醇作萃取剂,模拟研究了分壁式萃取精馏对摩尔分数为82%乙醇溶液脱水的分离过程。建立了分壁式萃取精馏模型,得到了优化的工艺参数,主塔理论板数为11块,精馏段理论板数为5块,回流比为0.10;副塔原料进料位置为第14块板,萃取剂进料位置为第4块板,隔板在副塔第18块板底端,萃取精馏段回流比为0.419,溶剂比为1.1。比较了分壁式萃取精馏和常规双塔2种流程下的能耗。模拟结果表明,采用分壁式萃取精馏,再沸器能耗降低了15%,节能效果明显。     

分壁式精馏塔分离醇类三元物系的实验研究

自行设计分壁式精馏塔用于分离乙醇-正丙醇-正丁醇三元物系,并获取最优的操作条件。当进料中乙醇-正丙醇-正丁醇的质量比为1∶3∶1,回流比为7,液体分配比为1∶3,气体分配比为1∶1时,实验的分离效果最佳,塔顶产品中乙醇的质量分数为98.15%、侧线产品中正丙醇的质量分数为95.67%、塔釜产品中正丁醇的质量分数为94.77%。     

盐析萃取结合隔壁塔分离多元醇-水混合体系

实验考察了当采用盐析萃取分离乙醇-正丙醇-异丁醇-水的混合体系时,改性萃取剂种类、质量比对各元醇、水的分配系数、各元醇的萃取率以及萃取相质量分数的影响。实验结果表明:改性萃取剂的萃取效果优于未改性萃取剂,改性萃取剂中盐的最佳比例只与含水量(质量分数)有关,盐析萃取效果最好的改性萃取剂为环己烷-醋酸钾,环己烷与原料的适宜质量比为0.75—1.5,醋酸钾与原料的最佳质量比为0.1。在实验基础上,采用Aspen Plus软件对盐析萃取结合隔壁塔工艺进行模拟,模拟结果表明:采用该工艺流程可得到纯度为95.78%的乙醇产品,99.00%的正丙醇产品和97.00%的异丁醇产品。     

分壁式萃取精馏分离乙腈-正丙醇的模拟研究

利用Aspen Plus软件,采用N,N-二甲基甲酰胺作萃取剂,研究了分壁式萃取精馏和常规双塔萃取精馏方法对该混合物的分离,均能实现混合物的有效分离。其中分壁式萃取精馏得到正丙醇和乙腈的质量分数分别为99.12%和99.59%。和常规双塔萃取精馏相比,分壁式萃取精馏流程再沸器热负荷降低11.02%,冷凝器热负荷降低17.69%,实现了有效节能。     

萃取精馏分离乙酸乙酯和丁酮的研究

采用萃取精馏的方法分离乙酸乙酯和丁酮共沸物系。选取乙二醇作为萃取剂,利用流程模拟软件Aspen Plus对流程进行模拟,分析不同萃取剂进料量、塔板数、回流比、进料位置等参数对产品质量分数及热负荷的影响。通过模拟发现,当乙二醇进料量为500 kg/h、萃取精馏塔塔板数为30、质量回流比为0. 45、原料进料位置为17块板、萃取剂进料位置为5块板,溶剂回收塔塔板数为10、质量回流比为0. 5、进料位置为第4块板时,可得到质量分数为99. 91%的乙酸乙酯及质量分数为99. 60%的丁酮。通过间歇萃取精馏实验对萃取精馏过程进行验证,发现萃取精馏塔塔顶可得到高达质量分数为98%的乙酸乙酯,证明了模拟结果的可靠性。     

萃取精馏隔壁塔精制含水乙腈流程模拟与优化

提出了采用萃取精馏隔壁塔精制含水乙腈的新工艺,并与传统的双塔萃取精馏工艺进行了对比。以乙二醇为萃取剂,采用Aspen Plus中的Rad Frac模型对新工艺进行了严格稳态模拟,并分析了溶剂比、主塔回流比、原料进料位置、分配比和互联位置对乙腈质量分数和全塔热负荷的影响。结果表明,隔壁萃取精馏塔的最佳工艺条件为:溶剂比为0.9,主塔回流比为22,原料进料位置为9~13块,分配比为4∶1,互联位置为21块板。完成相同的分离任务,比传统的双塔萃取精馏工艺节能62%,同时减少了设备的数目和投资。     

萃取精馏分离异丙醇-水共沸体系的模拟与优化

对异丙醇-水共沸体系的萃取精馏过程进行模拟与优化。以乙二醇为萃取剂,基于UNIFAC模型,使用Aspen Plus化工模拟软件中的RadFrac模块进行萃取精馏模拟,并利用灵敏度分析模块对各工艺参数进行灵敏度分析与优化。结果表明,以乙二醇做萃取剂分离异丙醇-水共沸体系是可行的。对于处理流量5000kg·h-1的异丙醇-水共沸溶液,精馏塔具有22块塔板时,原料进料位置在第16块塔板,萃取液进料位置在第3块塔板,摩尔回流比为1.4,萃取剂与原料的进料比为2∶1,塔顶异丙醇质量分数可达0.9981,萃取精馏塔的分离效果和热负荷达到最优。模拟和优化的结果对工业化设计和生产具备指导意义。     

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.     

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料，介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比，介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序，对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.