V/ SBA-15分子筛的制备及其对乙苯制苯乙酮反应的催化性能

以聚环氧乙烷-聚环氧丙烷-聚环氧乙烷三嵌段共聚物(简称P123)为模板剂,正硅酸乙酯为硅源,前驱体为柠檬酸氧钒配合物,采用水热法在酸性条件下制备了V-SBA-15有序介孔材料。考察了不同晶化时间、模板剂用量等因素对介孔分子筛V-SBA-15制备的影响。结果表明,最优晶化时间为96 h、模板剂用量n=1.0〔以n(P123)/n(V+Si)计〕,在该条件下所制备的材料具有类似于分子筛SBA-15高度有序的六方介孔结构,且活性组分钒在介孔氧化硅基体中均匀分散。用XRD、FTIR、BET、SEM及TEM等方法对制备的分子筛V-SBA-15进行结构表征,同时在乙苯制苯乙酮反应中以苯乙酮选择性及收率来验证催化剂的催化性能。结果表明,在催化氧化乙苯制苯乙酮反应较优工艺条件下,苯乙酮选择性及收率分别为82.0%和38.60%。     

V/SBA-15的制备及催化氧化性能研究

以柠檬酸处理过的偏钒酸铵为钒源,采用后合成法制备出了V/SBA-15负载型催化剂,研究其在氧化苯乙烯制苯甲醛反应中的催化性能.结果表明,在钒负载量低于15％时,V/SBA-15仍保持SBA-15的高度有序的二维六方孔道结构,且具有较大的比表面积和孔体积,负载的活性组分金属钒氧化物均匀分布在介孔分子筛表面;在优化条件下催化氧化苯乙烯制苯甲醛,苯乙烯转化率达65.62％,苯甲醛的选择性81.21％,且V/SBA-15具有较好的催化剂稳定性.     

Keggin结构钼钒磷杂多化合物催化氧化乙苯合成苯乙酮

合成了一系列具有Keggin结构的钼钒磷酸铵杂多化合物,并以它们作催化剂、过氧化氢为氧化剂催化乙苯氧化合成苯乙酮。研究发现,在该反应中,催化剂具有较好的催化性能,且杂多化合物的钒原子数增加,其催化氧化活性增强,在优化条件下,乙苯转化率达81.7%,苯乙酮选择性为100%。     

负载型Fe_2O_3对乙苯脱氢反应的催化性能

以正硅酸乙酯(TEOS)为硅源,分别以十六烷基三甲基溴化铵(CTAB)和P123为模板剂通过溶胶凝胶法、水热合成法合成出MCM-41、Al-MCM-41、SBA-15介孔分子筛,然后将其作为催化剂载体负载Fe2O3,应用到乙苯催化脱氢制苯乙烯的反应中,考察了不同负载量对乙苯脱氢反应性能的影响,探讨了催化剂的活性保持时间。结果表明,将介孔分子筛作为催化剂载体负载Fe2O3应用到乙苯脱氢反应,当负载量为60%时乙苯的转化率和苯乙烯的选择性均最高。当n Si/n Al为60时,Fe2O3/Al-MCM-41催化性能最好。Fe2O3/SBA-15所持续的活性时间最长。     

VO_x/SBA-16催化CO_2氧化乙苯脱氢性能

采用等体积浸渍法制备了不同钒负载量的VOx/SBA-16催化剂,通过XRD、N_2吸附、H_2-TPR和TGA表征和催化剂性能评价,研究了VO_x/SBA-16催化剂对CO_2氧化乙苯脱氢制苯乙烯的催化性能。结果表明,VO_x/SBA-16催化剂具有良好的乙苯脱氢活性,钒负载量为1.2 mmol/g的催化剂活性最佳,乙苯转化率可达57.6%,苯乙烯选择性98.6%。VO_x/SBA-16催化剂上的乙苯脱氢活性和稳定性明显高于VO_x/MCM-41,是由于SBA-16载体畅通的三维孔道结构更有利于钒物种的高度分散和反应介质的扩散,提高了催化剂的可还原性能,减缓了积炭的生成。     

VO_x/SBA-16催化CO_2氧化乙苯脱氢性能

采用等体积浸渍法制备了不同钒负载量的VOx/SBA-16催化剂,通过XRD、N_2吸附、H_2-TPR和TGA表征和催化剂性能评价,研究了VO_x/SBA-16催化剂对CO_2氧化乙苯脱氢制苯乙烯的催化性能。结果表明,VO_x/SBA-16催化剂具有良好的乙苯脱氢活性,钒负载量为1.2 mmol/g的催化剂活性最佳,乙苯转化率可达57.6%,苯乙烯选择性98.6%。VO_x/SBA-16催化剂上的乙苯脱氢活性和稳定性明显高于VO_x/MCM-41,是由于SBA-16载体畅通的三维孔道结构更有利于钒物种的高度分散和反应介质的扩散,提高了催化剂的可还原性能,减缓了积炭的生成。     

HClO4/SBA-15固体酸催化剂的制备及催化性能

将高氯酸引入具有较大孔径和比表面积的介孔分子筛SBA-15中,制备了用于异相催化的固体酸催化剂HClO4/SBA-15,并通过采用X-射线衍射(XRD)、多孔性检测、透射电镜(TEM)分析等方法,对其结构进行了分析表征.HClO4被负载后,材料的比表面积、孔径及孔容等多孔性参数都有所降低,但并没有破坏介孔分子筛SBA-15的孔道结构.为了证明HClO4/SBA-15的催化性能,探究了HClO4/SBA-15催化的选择性脱异丙叉基及乙酰化的一锅法反应.在室温条件和催化量的HClO4/SBA-15作用下,反应30 min内即可完成,产率达到98％,产物的化学结构通过1H NMR、13C NMR及MS等手段得到了表征.该法后处理简单、收率较高,而且不需要任何溶剂.     

Cr/SBA-15的优化合成及其环己烷氧化性能研究

采用高温水热嫁接的方法,通过调节反应溶液的p H和水热处理温度,成功地将金属铬离子嫁接到SBA-15氧化硅骨架上,制备得到高度规整有序的介孔孔道结构的Cr/SBA-15催化剂,并研究了Cr/SBA-15在以乙腈为溶剂,H_2O_2为氧化剂的环己烷催化氧化反应中的性能。结果表明,当p H=3,Si/Cr摩尔比为15时,合成的Cr/SBA-15催化剂具有高度有序的二维六方介孔结构,同时表现出良好的催化活性和选择性。反应温度为80℃,反应时间为4 h条件下,环己烷催化氧化的转化率可达17%,环己酮和环己醇的选择性分别为65%、35%。Cr/SBA-15催化剂重复使用3次后活性基本不变,表明该催化剂具有良好的稳定性。     

SBA-15固载磷钨酸催化剂的制备及催化合成叔丁基苯酚

以不同硅烷偶联剂改性的介孔分子筛SBA-15为载体、PW_(12)为催化剂,通过对SBA-15表面共价及非共价修饰制备磷钨酸@介孔分子筛/硅烷偶联剂复合催化剂PW_(12)@SBA-15/YSiX_3(YSiX_3=Apts、Atapts、Papts);并利用FT-IR、XRD、TEM、N_2吸附-脱附对其组成、结构及形貌进行表征。以改性SBA-15分子筛固载磷钨酸催化剂催化合成叔丁基苯酚为研究对象,考察不同硅烷偶联剂、反应温度、苯酚与叔丁醇物质的量比对催化合成叔丁基苯酚的影响,并获得合成叔丁基苯酚的最佳工艺条件,即反应温度145℃、n(苯酚)∶n(叔丁醇)=1∶2.5、重时空速2.2 h~(-1),该最佳反应条件下,PW_(12)@SBA-15/Apts催化剂催化合成叔丁基苯酚的催化活性最高,苯酚转化率为98.3%,2,4-二叔丁基苯酚选择性为57.3%.     

介孔材料催化合成芳酮的应用进展

综述了介孔材料合成芳酮的催化效果及应用进展。着重介绍了几种具有代表性的介孔材料MCM-41、SBA-15、HMS及其改性对芳酮的收率和选择性的影响。芳烃主要有苯环、萘环、杂环化合物,酰化试剂为羧酸、酸酐和酰氯。简述了催化剂失活的原因,结果表明,不同结构的介孔材料对不同的酰化反应具有不同的催化活性。     

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.     

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。     

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.