气相色谱法测定地下水中2,4-/2,6-二硝基甲苯

新建一种测定地下水中2,4-和2.6-二硝基甲苯的液液萃取-气相色谱法。甲苯作溶剂萃取水中的2,4-和2.6-二硝基甲苯,经DB-1701色谱柱分离,电子捕获检测器(ECD)检测。经过优化的色谱方法测定结果显示,2,4-和2.6-二硝基甲苯的检出限都为0.05μg/L,均具有较好的线性关系,相关系数都大于0.999;2,4-和2.6-二硝基甲苯的精密度分别为3.4%～12.6%和4.0%～15.5%;2.4-和2,6-二硝基甲苯的加标回收率分别是75.4%～126.0%和71.5%～122.6%。本方法准确、灵敏、快速,可为地下水样中2,4/2,6-二硝基苯的污染评价提供技术支持。     

2,4-二硝基甲苯的气相色谱分析

确立了试样以丙酮溶解 ,经OV -2 2 5石英毛细管柱分离的气相色谱分析方法。平均回收率为 98.92 %～ 1 0 4.69% ,标准偏差 (δ)为 0 0 0 2 0～ 0 0 0 97,相对标准偏差 (RSD)为 0 0 0 98%～ 2 5 8% ,为工业品 2 ,4 二硝基甲苯的质量控制提供了一个简便、准确、快速的分析方法。     

2,4-二硝基甲苯加氢影响因素研究

采用负载型Ni/硅藻土催化剂,以乙醇为溶剂,用于2,4-二硝基甲苯催化加氢法合成2,4-二氨基甲苯(2,4-二氨基甲苯)的反应。考察了搅拌转速、催化剂浓度、反应温度、氢气压力和反应时间对2,4-二硝基甲苯的转化率、加氢反应的速率和副产物焦油量的影响。结果表明,反应温度、催化剂浓度和反应时间是影响2,4-二硝基甲苯加氢的主要因素,最佳反应条件为:催化剂浓度0.9%～1.4%;反应温度110～120℃;氢气压力2.2～2.8 MPa;反应时间120 min。     

静态顶空-气相色谱质谱法测定地表水中硝基苯、硝基甲苯和硝基氯苯的研究

建立静态顶空-气相色谱质谱法测定地表水中硝基苯、硝基甲苯和硝基氯苯化合物的方法。采用正交试验讨论了平衡温度、平衡时间和加盐量等因素对测定结果的影响,结果表明,最优的实验条件为平衡温度85℃、平衡时间20min、加盐量3.0g。在此条件下,硝基苯、硝基甲苯和硝基氯苯能够有效分离,在2.0～100μg·L^-1范围内线性良好,相关系数r>0.999,检出限为0.19～0.40μg·L^-1,加标回收率为88.8%～108.9%,相对标准偏差(n=8)为2.2%～8.9%。以地表水为基体做加标回收试验,加标回收率达到93.5%～113.1%,相对标准偏差在3.3%～5.1%。     

醇类和2,4-二硝基甲苯混合密度的测定与关联

甲醇、乙醇、2,4-二硝基甲苯为合成重要有机中间体TDI的重要原料。通过激光法测定了常压下甲醇-2,4-二硝基甲苯和乙醇-2,4-二硝基甲苯体系在293.15 308.15 K的混合密度,并进一步计算得到了超额体积VE。线性拟合了体系293.15 308.15 K密度与组成的关系,Redlich-Kister方程关联了超额体积与组成的关系,回归了模型系数,关联的最大标准偏差均小于5%。研究为TDI非光气法合成反应的工业化设计和放大提供了基本物性数据。     

水合肼还原2,6-二硝基甲苯的研究

将FeCl3溶液快速滴加至NaOH溶液中,制备了FeO(OH)催化剂,用于催化水合肼还原2,6-二硝基甲苯,得到2-氨基-6-硝基甲苯和2,6-二氨基甲苯。结果表明,水合肼与2,6-二硝基甲苯的摩尔比为1.6:1,反应40 min时,2-氨基-6-硝基甲苯的收率可达94%;水合肼与2,6-二硝基甲苯的摩尔比为3.1:1,反应50 min时,2,6-二氨基甲苯的收率可接近100%。     

毛细管柱气相色谱法测定水中硝基甲苯类化合物的方法研究

本文以甲苯为萃取剂,用毛细管柱进行分离,带电子捕获检测器的气相色谱进行定性定量分析,建立了液液萃取-毛细管柱气相色谱法同时测定水中对硝基甲苯、2,6-二硝基甲苯、2,4-二硝基甲笨、2,4,6-三硝基甲苯4种硝基甲苯类化合物的方法.结果表明:该方法对4种硝基甲苯类化合物分离以及线性相关性好,平均加标回收率为90.2％～...     

2—氟—4—硝基甲苯、2—氟—6—硝基甲苯的合成研究

1 前言 2-氟-4-硝基甲苯、2-氟-6-硝基甲苯是合成新型农药杀虫剂的一种极重要的中间体。这二种化合物的沸点很高(2-氟-4-硝基甲苯的沸点是282℃,而2-氟-6-硝基甲苯的沸点是常压下288℃)。此外,室温下二者都是固体,易结晶(2-氟-4-硝基甲苯的熔点是62～64℃,2-氟-6-硝基甲苯的熔点是65～67℃)故以前市场上只供应了含量在70％左右的混合物。     

2,6-二硝基甲苯的制备

用硫化铵作还原剂对工业二硝基甲苯进行选择性还原,从而使2,4-二硝基甲苯和2,6-二硝基甲苯分离制备出标题化合物。实验所得工艺条件:反应温度40℃,反应时间4 h,二硝基甲苯∶硫化铵(摩尔比)=1.2∶1。纯度达到98%以上(GC分析),收率最高为75%。产物结构经TLC、IR进行表征。     

液液小体积萃取-气相色谱质谱法测定地表水中2,4-二硝基甲苯和2,4-二硝基氯苯

本文建立了一种液液小体积萃取结合气相色谱质谱法测定地表水中2,4-二硝基甲苯和2,4-二硝基氯苯的方法.实验结果表明,2,4-二硝基甲苯和2,4-二硝基氯苯在10.0～ 160μg·L-1浓度范围内线性关系良好,加标回收均在92.8％～ 103.5％之间,精密度测试结果范围在1.43％～4.05％之间,符合分析测试的要求.本方法操作简便快速、有机试剂用量少、样品测定结果精密度和准确度较高,适用于地表水中2,4-二硝基甲苯和2,4-二硝基氯苯的测定.     

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。