GC-MS测定番茄及土壤中二甲基二硫醚残留含量的分析方法

[目的]建立GC-MS测定二甲基二硫醚在番茄果实及土壤中的残留量分析方法。[方法]样品经甲醇提取,用正己烷液液分配净化后采用气相色谱-质谱联用仪(GC-MS)进行测定。[结果]二甲基二硫醚标准曲线的线性范围为0.002~1mg/L,相关系数为0.9999。二甲基二硫醚在番茄中的平均回收率为76.4%~82.1%相对标准偏差为3.1%~8.9%;在土壤中的平均回收率为71.5%~84.0%,相对标准偏差为1.5%~5.7%。方法的检出限(LOD)为1.5×10~(-3)ng,定量限(LOQ)为5.0×10~(-3)ng,符合农药残留分析要求。[结论]建立了一个简便、快捷、准确的二甲基二硫醚农药残留分析方法。     

钛硅分子筛(TS-1)催化氧化二甲基硫醚制备二甲基砜的研究

以二甲基硫醚和双氧水为原料、钛硅分子筛为催化剂制备了二甲基砜,确定了最佳工艺条件,即常温下钛硅分子筛为二甲基硫醚质量的7%,二甲基硫醚与双氧水的摩尔比1∶1.05,反应时间1.5 h,二甲基硫醚转化率达99%以上,二甲基砜收率达98%以上。     

吸附法脱除液化石油气中的二甲基二硫醚

采用等体积浸渍法制备了CuY和CuX分子筛吸附剂,在固定床中考察了分子筛吸附剂种类、吸附温度、原料空速和再生次数对脱除液化石油气中的二甲基二硫醚效果的影响。实验结果表明,CuY和CuX分子筛吸附剂保持了原有的骨架结构;CuY分子筛吸附剂可作为脱除液化石油气中二甲基二硫醚的吸附剂;在温度为25℃,压力为0.6 MPa,空速为1 h-1时,CuY分子筛吸附剂的穿透硫容为1.02%;吸附剂具有较好的再生性能。     

滇韭挥发性成分分析

用同时蒸馏萃取装置提取挥发油并用气相色谱-质谱联用仪对滇韭挥发性成分进行了分离和鉴定,分离并鉴定出95个组分,占峰面积的71 50%,用面积归一化法测定了各种成分的质量分数,其主要挥发性成分为:w(三甲基磷化硫醚) =0 15%,w(丁基丙烯基硫醚) =0 03%,w(1, 2 二乙硫基乙烯) =0 38%,w(烯丙基甲基硫醚) =0 79%,w(二烯丙基硫醚) =0 11%,w(2 甲氧基茴香硫醚) =0 15%,w(甲基乙基二硫醚) =0 02%,w(二甲基二硫醚) =0 08%,w(二烯丙基二硫醚) =0 10%,w(二丙基二硫醚) =1 03%,w〔(甲硫基)二甲基二硫醚〕=0 17%,w(甲基1 丙烯基二硫醚) =0 32%,w(二2 羟基乙基二硫醚) =0 11%,w(二甲基三硫醚) =0 02%,w(甲基2 丙烯基三硫醚) =0 06%,w(二2 丙烯基三硫醚) =0 45%,w(二丙基三硫醚) =1 54%,w(二甲基四硫醚) =0 39%,w(4H 噻唑) =0 02%,w(4, 5 二甲基噻唑) =0 50%,w(4, 5 二甲基异噻唑) =0 06%,w(5 甲氧基噻唑) =0 24%,w(3, 4 二甲基异噻唑) =0 22%,w(3, 4 二甲基噻吩) =0 27%,w(4H 2 乙基噻吩) =0 02%,w(1, 3 二噻烷) =0 03%,w(1, 3, 5 三噻烷) =0 03%,w(1, 2 二硫戊环) =0 09%,w〔2, 4 二硫杂戊烷〕=0 98%,w(3, 5 二乙基1, 2, 4 三硫戊环) =0 55%,w(二甲基亚砜) =0 05%,w(3 甲硫基丁醛) =0 02%,w(2 甲基硫代乙酸) =0 37%,w     

甲基叔丁基醚中有机硫化物定性和定量研究

为确定工业甲基叔丁基醚(MTBE)中的有机硫化物的种类和含量,文中采用GC-MS、有机元素分析仪和微量硫气相色谱仪对某厂MTBE中有机硫化物种类进行了定性和定量研究,探索研究了硫化物类型对MTBE脱硫过程的影响。由结果可知:二甲基二硫醚、乙基甲基二硫醚、甲基叔丁基硫醚、二乙基二硫醚4种高沸点硫化物为MTBE中的主要硫化物,其中二甲基二硫醚和乙基甲基二硫醚2种硫化物的含硫质量分数为97.4%。采用精馏方法脱除MTBE中的硫化物,关键在低沸点硫化物的控制与处理。     

炼厂硫化氢合成二甲基亚砜技术开发

开发了以炼厂硫化氢为原料制备二甲基亚砜的绿色清洁生产技术。硫化氢合成二甲基硫醚,采用分子筛催化剂,运行2048h后,甲醇转化率和二甲硫醚选择性保持在95%以上,催化性能优异;以二甲基硫醚和过氧化氢制备二甲基亚砜,过氧化氢和二甲硫醚的转化率均在95%以上,二甲亚砜的选择性在99%以上,产品经分离纯度可达99.5%以上,达到工艺一级品要求。该工艺条件温和、路线简单,具有绿色、环保等特点,具有较好的工业化应用前景。     

过渡金属改性Y型分子筛吸附脱除低碳烃中二甲基二硫醚

采用离子交换法制备了CoY、CuY、NiY分子筛,并在固定床吸附器上考察了工艺条件及原料烯烃含量对改性分子筛吸附脱除二甲基二硫醚性能的影响。采用密度泛函理论计算二甲基二硫醚及异丁烯在CoY、CuY、NiY分子筛上的竞争吸附行为。最后考察了高温水蒸气对吸附剂的再生效果。结果表明,CoY、CuY和NiY分子筛对二甲基二硫醚的动态饱和吸附硫容分别为47.5mg/g、36.3mg/g和40.2mg/g;其中CoY和NiY分子筛硫容量受烯烃含量的影响较大,CuY分子筛受影响较小。计算结果表明,吸附过程中S—S键的Mayer键级变化不大,烯烃中C=C键双键性质减弱。二甲基二硫醚在CoY、CuY和NiY分子筛上的吸附能分别为–59.5k J/mol、–22.2k J/mol和–30.4k J/mol,与实验数据吻合。吸附饱和后的分子筛经160℃水蒸气脱附60min后能够有效再生,且多次再生后吸附剂硫容仍保持在新鲜吸附剂的97%以上。     

戊唑醇中间体2-[2-(4-氯苯基)乙基]-2-(1,1-二甲基乙基)-环氧乙烷合成工艺的改进

[目的]研究一种合成2-[2-(4-氯苯基)乙基]-2-(1,1-二甲基乙基)-环氧乙烷过程中替代二甲基硫醚的方法。[方法]用难挥发的甲基硫醚代替二甲基硫醚合成硫鎓盐,然后与1-(4-氯苯基)-4,4-二甲基-3-戊酮反应合成目标化合物,并对反应条件进行优化。[结果]用正辛基甲基硫醚合成2-[2-(4-氯苯基)乙基]-2-(1,1-二甲基乙基)-环氧乙烷,收率达90.5%,操作过程气味小。[结论]用正辛基甲基硫醚替代二甲基硫醚进行硫叶立德反应,可以克服反应过程的恶臭气味,具有工业化应用前景。     

聚合离子液体对二甲基二硫醚的吸附研究

二甲基二硫醚作为MTBE中的主要硫化物之一,其不但含量高而且很难去除,成为一些MTBE生产厂家的难题。文中研究合成了嫁接硅胶的金属酞菁功能化聚合离子液体。对研究合成的6种金属酞菁功能化聚合离子液体,考察了其对二甲基二硫醚的吸附性能。并详细考察了金属酞菁单体、载体、单体用量和吸附剂用量等影响因素对吸附效果的影响。结果表明硅胶负载金属酞菁铁功能化的聚合离子液体吸附剂吸附效果最佳。最优工艺条件为:金属酞菁用量为载体的25%,吸附剂用量为150 g/L,吸附时间为15 min,吸附去除率高达83.6%。吸附剂重复使用5次后,吸附去除率仍能达到80%以上。     

电厂尾气处理工艺流程设计

二甲基硫醚具有需求量大,附加值高等特点。是无色透明、有特殊臭味的液体,是生产二甲基亚砜、蛋氨酸及农药的中间体,可作为溶剂。二甲基硫醚的制备由制硫磺工段、制硫化氢工段和制二甲基硫醚工段三个部分组成。含硫烟气经除尘脱硝后进入制硫磺工段,经过一系列精制后产生的气态硫磺与预热后的氢气混合后进入制硫化氢工段,将反应所得硫化氢气体与甲醇蒸汽、氮气、水蒸气混合后送入制二甲基硫醚工段,反应所得二甲基硫醚经过一系列的精馏分离后得到纯度为99.07%的二甲基硫醚产品。     

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。