反应精馏过程图解法设计策略研究

从反应精馏过程图解法设计的理论研究出发,探讨了反应空间、转换组成变量以及剩余曲线等应用范围和局限性;通过分析反应精馏操作线方程的变化,提出了图解法设计反应精馏过程的策略;（1）用奇异点判断法结合实验数据可判定应用反应精馏过程的可行性;（2）借助反应空间可判断该过程能否在单塔中得到完全分离;（3）图解法设计的多种设计结果及相应对策。采用实例验证了该策略的可行性。     

基于化学热泵系统的叔丁醇脱水反应精馏过程

采用柱状阳离子交换树脂S-54作催化剂研究了叔丁醇脱水的反应精馏过程.在实验基础上建立了该过程的数学模型,采用超松弛法,并以动态方程逼近计算稳态过程对模型进行了求解,计算结果与实验结果吻合良好.在以上研究基础上考察了不同进料流量、进料组成、进料位置以及不同回流比等对反应转化率的影响,进行了上述工艺操作参数的模拟寻优,得到以下结论：反应精馏操作实现了水从反应体系中的有效移除,减小了水对反应的阻害作用,使叔丁醇接近完全分解;同时改变操作压力可以适用不同温度热源的热量回收要求.     

二元精馏图解法求理论板数的几个问题

<正> 在二元精馏的简化计算中,通常用x-y图解法求理论板数和进料位置。但是在现有文献[1,2]中,x-y图解法不能给出进料段中汽、液各流股的组成以及在进料段处精馏段操作线和提馏段操作线的断开位置。本文所推荐的方法避免了上述缺点,从而在x-y图上能较方便地确定出适宜的进料板位置。     

丙酮连氮催化水解反应精馏工艺的研究

对丙酮连氮催化水解反应精馏制水合肼的工艺过程进行了模拟与实验。采用NRTL方程与RadFrac模型,使用实验回归得到的动力学方程与汽液平衡参数,对丙酮连氮催化水解精馏制水合肼的工艺进行模拟计算。考察了回流比、丙酮连氮与水的摩尔比、进料位置等工艺条件对丙酮连氮水解反应的影响,并通过实验验证了模型的准确性和可靠性。在模拟和实验的基础上,确定了最优工艺条件:精馏段理论板数为5,反应精馏段理论板数为14,回流比为2,丙酮连氮与水的摩尔比为1∶7,原料进料位置为第9块板。在此条件下,丙酮连氮的水解率可达99%以上,塔釜肼质量分数为34%,并且得到了全塔的温度和质量分数分布曲线,为工业生产提供了依据。     

反应/分离集成系统塔板组成线设计法研究

反应/分离系统的集成是对现有工业过程进行强化的主要途径之一。文中在精馏塔板组成线的基础上,推导出了反应精馏塔板组成线基本方程及设计可行性判据,提出了给定进料和一个目标产品组成的塔板组成线反应精馏设计的新策略,并对非理想性较强的MTBE反应体系进行了实例设计计算。结果表明,提出的设计策略能同时获得多组可行设计方案,可有效地对单一和集成型反应精馏塔进行设计,结果与Aspen P lus的模拟结果吻合较好。     

轻汽油反应精馏醚化过程模拟

利用Aspen lus软件对轻汽油醚化的反应精馏过程进行了模拟.采用平衡级模型RedFrac模块作为反应精馏模型,对C5活性烯烃与甲醇醚化生成TAME反应进行了模拟计算,考察了反应精馏塔的进料醇烯比、进料位置,回流比、塔釜温度及操作压力几个因素对醚化转化率的影响,获得最优的反应条件,研究结果可以为轻汽油醚化过程和工艺设计提供依据和借鉴.     

醋酸-水体系复杂精馏过程模拟与优化

醋酸的缔合效应使得醋酸 水体系的非理想性非常严重,文中考虑汽相的二聚缔合,液相用NRTL方程修正其非理想性,计算出的常压下汽液平衡数据与文献值比较吻合,并把所推导的热力学模型用于多股进料精馏模拟计算,确定了精馏过程的最佳回流比以及精馏塔内温度、质量分数分布,并讨论进料温度、质量分数等因素变化对精馏过程的影响,获得了对醋酸 水体系精馏过程实际生产具有指导意义的优化操作参数。     

反应精馏法合成醋酸丁酯的模拟研究

文章采用Aspen Plus对反应精馏法生产醋酸丁酯过程进行稳态模拟。对塔板数、进料位置及进料比进行了优化,得到了精馏塔理论板上的温度、汽(液)相流量组成分布和再沸器热负荷。结果表明进料位置和进料比对年总成本TAC影响很大。该计算对反应精馏法合成醋酸丁酯工艺的设计和操作具有实际意义。     

催化精馏合成乙酸乙酯的工业试验

以固体酸为催化剂,在中试催化精馏塔中进行了乙酸与乙醇反应制备乙酸乙酯的工业试验,试验塔的精馏段塔径为600 mm,内装陶瓷规整填料,反应精馏段塔径为1 000mm,内装7层立体催化精馏塔板.采用连续操作,考察了不同的回流比、釜酸质量分数、进料流量对反应和分离过程的影响,同时测定了塔板上气液相质量分数的分布.通过试验得到...     

反应精馏生产乙酸正丁酯分析与优化

使用了Aspen Plus11.1模拟正丁醇与乙酸反应精馏生成乙酸正丁酯的反应精馏过程,对进料温度、回流比和进料位置进行了优化分析,得到了最佳工艺参数:进料温度常温;回流比为1;进料位置为第六块塔板。另外,模拟得到了反应精馏塔的温度和浓度分布,为指导乙酸正丁酯的工业生产提供了理论参考。     

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.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

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.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。