粗TiCl4有机物除钒的研究

在粗TiCl4的几种主要除钒方法中,有机物除钒法是一种比较理想的除钒方法.介绍了粗TiCl4除钒的国内外现状,有机物除钒的基本原理,着重从热力学方面和动力学方面对有机物与VOCl3相互作用进行了分析.     

粗四氯化钛除钒工艺现状及发展趋势

概述了使用铜丝、有机物、硫化氢和铝粉4种物质除去粗四氯化钛中的杂质钒方法的优缺点,通过比较指出有机物除钒法和铝粉除钒法是较理想的粗四氯化钛除钒方法。最后,对有机物除钒法目前存在的问题及解决方案进行了分析。     

粗四氯化钛的铝粉除钒工艺及机理研究

铝粉除钒法是一种重要的粗四氯化钛精制工艺.针对钒含量较高的粗四氧化钛,系统考察了铝粉用量对除钒效果及除钒时间的影响,并在此基础上探讨了铝粉除钒工艺的动力学.采用HSC热力学软件对相关反应的标准Gibbs自由能△Gθ和化学反应焓变△H进行了计算,分析了铝粉除钒工艺机理.     

五氧化二钒的供应问题

钒在自然界中散布很广,但其存量稀少,时常与铁、铬矿一同出现,有时也可以在陶土、洋灰、铁铝氧石或田地裹找到。矿物油中除含有硫化物及大量氯化钠外,也有钒化合物。据文献报导,氧化钒可使耐火建筑物变为矿渣,并且毁坏金属部份。关于汽锅炉、洋灰旋转炉及矿渣熔融性等的研     

TiCl_4气相氧化法制备金红石型TiO_2的工艺

以粗TiC l4(98.0%)为主要原料,通过白矿物油除钒提纯处理后,采用气相氧化法制备出金红石型TiO2,并分析了粉体的相关性能。研究表明,制备的金红石型TiO2具有较高的晶型转化率(100.0%)、白度(102.08%)和消色力(123%),且粒度适宜(258 nm)、粒度分布较窄、近似球形、分散性好等优异性能。A lC l3蒸气在气相反应中起到了晶型转化剂的作用。当A lC l3加入量增加至2.6%以上时,TiO2的晶型转化率达到了最大值100.0%。     

强制循环法粗四氯化钛有机物除钒工艺研究

以有机脂肪酸作为粗四氯化钛除钒试剂,采用强制循环法工艺,通过提高四氯化钛过热器管程内四氯化钛的流速,实现四氯化钛液体对换热器内部的自清洁。结果表明:强制循环法粗四氯化钛有机物除钒工艺能够满足工业化连续生产的要求,可以得到完全满足标准要求的产品。     

铝粉除钒精制四氯化钛工业化试验存在的问题及改进方案

论述了粗四氯化钛铝粉除钒精制四氯化钛的原理及试验历程,对工业化生产试验中存在的问题提出了改进方案。     

粗四氯化钛中低沸点杂质分离的探讨

粗TiCl4中主要含SiCl_4、AlCl_3等杂质。本文利用Aspen Plus模拟软件,计算了粗四氯化钛中低沸点杂质的精馏分离过程,得到了粗四氯化钛中低沸点杂质分离的相关参数,并进行了精馏过程的灵敏度分析,指出在生产过程中应综合考虑生产成本费用与产品要求等因数,选择合适的回流比与组分回收率。     

高温气相法可控制备纳米TiO2

通过火焰反应器结构设计,实现TiCl4高温气相氧化过程可控制备纳米TiO2粒子,新型火焰设计保证了TiCl4低温进入高温反应区,预热过程隔离保护喷嘴,避免了结疤堵塞;通过实验条件控制颗粒平均粒径和粒径分布,较低的TiCl4气相浓度、较高的载气流速有利于小粒径TiO2颗粒的生成。载气流速增加,中心TiCl4火焰形态由层流向湍流发展,焰长缩短,颗粒平均粒径减小。CH4燃气流量增加,高温反应区扩大,颗粒停留时间增加,颗粒尺寸增大。二次氧气的补充,提高了氧气与TiCl4的预混,有效地减小了产品TiO2颗粒的粒径。获得的TiO2产品平均粒径在20～80 nm之间。     

金属钒的制备方法综述

金属钒性能特殊,素有“工业味精之称”,在冶金、化工、航空、能源、原子能等领域应用广泛。金属钒属于稀有高熔点活泼金属,其高纯金属制备困难,目前主流的制备方法为铝热还原钒氧化物制备粗钒与粗钒真空熔炼提纯的联合工艺,该法能耗高、钒收率低。基于钒氧化物和钒氯化物的热力学性质,研究者还提出了诸多含钒前驱体还原制备粗钒及粗钒精炼制备高纯钒的方法,具体包括钙热还原、镁热还原、真空碳热还原、硅热还原、碳热还原-氮化热分解、熔盐电解脱氧等粗钒制备方法,及熔盐电解精炼、碘化物热分解、固态电迁移等粗钒精炼方法。本工作对上述粗钒制备及粗钒精炼涉及的十余种方法开展了较全面的综述,论述了这些方法的基本原理、技术特点、效果及问题等,以期为高纯金属钒的新制备技术研发和技术升级提供全面的参考依据。     

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.     

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.     

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。