苯乙烯适宜贮存工艺条件研究

测定了贮存时间、阻聚剂TBC(叔丁基邻苯二酚)含量和铁锈量对苯乙烯聚合物和过氧化物含量的影响,通过均匀设计实验考察了苯乙烯聚合物含量与贮存条件的关系.结果表明,当苯乙烯聚合物的质量分数不高于10 mg/kg(优等品指标)时,在贮存温度为20℃条件下,苯乙烯可贮存8~9 d;在30℃时,可贮存5 d;由拟合得到的苯乙烯聚合物含量与贮存条件的关系式解得:贮存温度为18℃,TBC质量分数为13.8 mg/kg,贮存时间为12 d.     

丁二烯生产装置爆炸事故发生的原因及防范措施

通过红外光谱、X射线衍射仪及元素分析等对丁二烯生产装置的爆炸残留物进行了分析,跟踪考察了丁二烯装置运行过程中不同部位氧含量与亚硝酸钠浓度的相互关系,探讨了装置发生事故的原因。结果表明,丁二烯装置发生爆炸事故的根本原因在于系统中氧、铁锈等杂质的存在使得装置中容易生成过氧化物,进而生成过氧化聚合物,从而引发爆炸事故。目前在用的亚硝酸钠抑制剂除氧效率不高,因此要控制系统中的氧含量需要从源头上的原料碳四做起。此外提出了一些具体的安全措施。     

C_5贮运工艺条件研究

为了研究裂解C5在贮运及生产过程中自聚或共聚生成聚合物量,采用气相色谱及面积归一法分析了C5的组成,并对其贮运条件进行研究,考察了贮存温度、时间、含铁锈质量分数、含氧质量分数对C5聚合物生成质量分数的影响。结果表明:随着温度升高和时间的延长,C5中聚合物生成质量分数明显增加;贮存温度低于35℃,时间4 d以内,聚合物的生成质量分数可控制在5%以内;铁锈和氧气会促进C5中双烯烃的聚合;建立了C5聚合物生成质量分数和时间、温度的关系关联式,在实验条件范围内,关联式能较好地反映聚合物生成质量分数和时间、温度的关系。     

裂解气相色谱-质谱法快速测定苯乙烯-丁二烯-苯乙烯嵌段共聚物中聚合单元含量

研究裂解气相色谱-质谱法测定苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)中苯乙烯和丁二烯含量。确定裂解条件如下:裂解温度590℃,裂解时间3s,样品量0.2mg(粒径小于1mm)。试验结果表明,该方法测定SBS中苯乙烯和丁二烯含量快速、准确,相对误差小于5%,相对标准偏差为0.32%～1.99%。     

改性活性炭吸附硫化氢性能研究

研究了改性活性炭(7%碳酸钠溶液浸渍)吸附硫化氢(H2S)气体的影响因素.利用改性后的活性炭考察氧含量、反应温度、空速等对活性炭吸附硫化氢的影响.结果表明,在反应条件下低氧含量时活性炭的吸附容量随氧含量增加而增加,但氧含量增加到3.5%后,氧含量对吸附容量的影响越来越小;在20～70℃范围内物理吸附发生主要作用,70～95℃化学吸附占主导作用,随着温度的增加,物理吸附逐渐向化学吸附转化,所以吸附容量先减小后增大;随着空速的增加,改性炭的吸附容量减小;改性后活性炭吸附H2S适宜的操作条件为氧含量2%,温度95℃,空速1000～2000 h-1.     

影响顺丁橡胶生产装置运行的原因分析

正影响顺丁橡胶(BR)生产装置产品质量和运行周期的因素较多,本工作分别从丁二烯精馏系统自聚物的形成、生产设备腐蚀和聚合系统凝胶生成3个方面对BR生产装置运行周期的影响进行分析,并提出相应的解决方案。1丁二烯自聚BR生产装置系统中由于原材料(己烷、丁二烯、催化剂)工艺处理、生产设备管线锈蚀、操作人员的不当操作等会引入微量氧、过氧化物、铁锈、     

顺酐溶剂吸收装置工艺参数模拟优化与分析

采用Aspen Plus化工模拟软件10.0版本对顺酐吸收塔的吸收过程进行了模拟计算,考察了反应气进料温度、反应气中顺酐含量、循环吸收剂用量和循环吸收剂中水含量变化对塔顶尾气中顺酐含量和塔釜富顺酐吸收剂中水含量的影响规律。模拟计算结果和装置运行数据对比表明,在相同条件下,模拟值与装置运行值误差小于1%,说明该模拟方法可靠。为确保塔顶尾气中顺酐含量不高于0.02%（质量分数,下同）,塔釜富顺酐吸收剂中水含量不高于0.2%,同时降低后续装置操作负荷,模拟优化分析得到吸收塔适宜的工艺参数：反应气的进料温度为108℃,反应气中顺酐含量为2.36%,循环吸收剂的用量为反应气中顺酐质量的3.12倍。     

丁二烯过氧化自聚物生成原因的考察

兰化公司橡胶厂中试室模拟本厂橡胶系统回收丁二烯装置的操作条件,对丁二烯过氧化自聚物生成的原因进行了考察。结果表明:1.丁二烯过氧化自聚物的生成速率随氧含量的增加而加快,当氧/丁二烯约0.5—0.6     

流化床干燥过程中全粒级褐煤的自燃特性研究

本文以氧含量为10.5%的模拟烟气为干燥气体在流化床干燥器中对通辽全粒级褐煤的自燃特性进行了研究,考察了粒度0.5～3.0 mm的煤样的自燃特性.实验结果表明:干燥过程中发生自燃的危险性随着干燥温度和干燥时间的增加而增加;在气流温度为200℃和220℃条件下可安全完成干燥过程:若控制干燥时间不超过8 min,可在200℃～240℃下完成干燥过程.不发生自燃.     

乳化沥青改性用丁苯胶乳的合成

以丁二烯和苯乙烯为单体,采用非离子乳化剂与阴离子乳化剂组成的复合乳化体系,在过氧化物与亚铁盐构成的氧化还原引发体系作用下,合成了性能良好的乳化沥青改性用丁苯胶乳,讨论了影响聚合过程及胶乳性能的因素.结果表明,适宜的乳化剂用量为5.8～9.3份(质量,下同),最佳的引发体系组成为0.20～0.40份过氧化物与0.02～0.04份亚铁盐;采用分批加入相对分子质量调节剂(0.386～0.550份)方式和三段控温模式(初期反应温度在16～20℃、中期反应温度在28～30℃及后期温度在38～40℃)更有利于控制胶乳的门尼黏度和结构凝胶含量.     

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.     

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。     

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.     

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.