水热碱蚀与碱溶滤联合处理制备介孔丝光沸石

以硅酸钠溶胶和铝酸钠为硅、铝源,采用水热合成和离子交换法制备了质子型丝光沸石(H-MOR)。研究水热碱蚀与碱溶滤联合处理对H-MOR改性样品的介孔结构、晶体形貌、组成及酸性质的影响。结果表明:用初始浸渍液对H-MOR进行水热碱蚀,H-MOR骨架脱硅选择性高,晶体含有均一的筛状介孔;水热碱蚀与一次碱溶滤处理的样品具有尺度分布较窄的槽形介孔,沸石骨架硅铝比降低而介孔率增加;再度进行碱溶滤处理,沸石的最可几介孔尺寸和累计介孔体积进一步增大,而残留抽出物(无定形SiO2–Al2O3)的硅铝比为生成介孔丝光沸石晶相的5倍以上。联合碱处理的丝光沸石样品具有骨架脱硅选择性和介孔率高、介孔分布(4.4~5.7nm)可控的特性,其结晶度、固有微孔结构和酸性质退化程度较低。     

碱酸联合处理法ZSM-22沸石介孔改性研究

通过水热合成及铵交换制备不同硅铝比的氢型沸石H-ZSM-22;用碱、酸介质对H-ZSM-22样品进行介孔改性。研究起始沸石硅铝比对改性沸石相对结晶度、介孔结构、晶貌和产率的影响。N2吸附-脱附和XRD分析表明,改性沸石兼有结晶性的微孔-介孔结构;随着起始沸石n(Si)∶n(Al)由31.7增至43.2,改性沸石介孔体积出现极大值而结晶度保留率和产率呈相反的变化趋势;典型样品[n(Si)∶n(Al)=37.0]的介孔体积高达0.44cm3/g,结晶度保留率和相对产率分别为56.0%、44.4%。SEM观察显示,改性沸石的附加介孔结构主要源于H-ZSM-22骨架脱硅、脱铝产生的结构缺陷。     

丝光沸石骨架脱硅与介孔改性研究

采用碱溶和酸洗过程对合成的MOR沸石进行骨架脱硅与介孔改性。结果表明,碱溶-酸洗联合处理促进 MOR 骨架选择性脱硅和晶内介孔的形成;脱硅沸石的相对结晶度和产率随介孔率的增加呈下降趋势。辅以酸洗可调整碱处理沸石的硅铝比,改进其酸强度分布和介孔率。     

MFI型硅铁沸石水热合成、介孔改性与结构表征

采用无机铁、硅原料合成不同组成的MFI型硅铁沸石。通过碱酸处理对质子化硅铁沸石进行介孔改性。用X射线衍射、Fourier变换红外光谱、紫外–可见光谱、N_2吸附、扫描电子显微镜和能量色散X射线谱表征沸石的晶体和孔结构性质,探究骨架Si/Fe摩尔比与晶内介孔率和Si、Fe脱除行为的关系。结果表明:合成的硅铁酸盐是结晶性好的Fe~(3+)同构取代MFI型沸石;系列改性硅铁沸石具有较高的结晶度保留率、脱硅选择性、介孔率及二级介孔分布特征。骨架Si/Fe比是影响沸石选择性脱硅和介孔形成的关键因素。起始Si/Fe比为60~120的改性沸石具有更高的介孔率及Si、Fe脱除效率。     

MFI型金属硅酸盐合成、介孔改性与骨架原子脱除行为

采用无机原料合成高硅沸石ZSM-5、FeMFI、TS-1和超高硅SH-ZSM-5(摩尔比Si/Al=402.4),通过骨架Si、金属原子(M=Al、Fe、Ti)抽提对系列H-MFI沸石进行介孔改性.借助XRD、FT-IR、UV-vis、77 K N2吸附-脱附和SEM/EDX技术,研究沸石晶体结构、金属原子嵌入率、介孔率及骨架Si、M脱除行为.结果表明,与前体相比改性沸石Si/M摩尔比降低,高选择性脱硅沸石具有多级微、介孔结构和较高织构介孔率.引入附加介孔使BET比表面积和总孔体积显著增加.同构沸石介孔形成受骨架电荷密度、嵌入金属原子种类、晶体形貌与尺度等因素的影响.骨架原子脱除效率按ZSM-5、FeMFI、TS-1次序递减.聚集态TS-1、SH-ZSM-5因过度脱硅导致相对产率和介孔生成效率下降.     

酸碱复合改性丝光沸石催化4-异丙基联苯异丙基化

采用酸碱复合改性的方法,制备了同时具有微孔和介孔孔道的丝光沸石,用于固定床4-异丙基联苯的异丙基化反应。通过X射线衍射(XRD)、透射电子显微镜(TEM)、NH3程序升温脱附(NH3-TPD)、N2物理吸附脱附等方法对改性丝光沸石进行表征。结果表明,碱改性处理调变了丝光沸石的孔道结构和酸性质,同时保持了其MOR拓扑结构,提高了4-异丙基联苯的转化率和反应的稳定性。碱处理后再进行酸处理,可以有效清除碱处理过程中产生的非骨架铝物种和样品外表面的酸中心,提高目的产物4,4'-二异丙基联苯的选择性。     

碱改性介-微孔HZSM-5分子筛催化乙醇脱水制乙烯性能

对两种不同硅铝比的HZSM-5分子筛进行碱处理,制备介-微孔复合HZSM-5分子筛,研究乙醇脱水制乙烯的催化性能,并考察碱溶液浓度和处理温度对HZSM-5分子筛孔结构和表面酸性的影响。结果表明,适宜的碱处理条件有利于分子筛发生骨架脱硅和脱铝,从而形成介孔。碱处理对硅铝比低的HZSM-5分子筛酸性质影响明显,而硅铝比高的HZSM-5分子筛在碱处理过程中酸性质变化不明显,更易发生脱硅和脱铝而形成更多介孔。碱改性介-微孔HZSM-5分子筛催化剂使乙醇脱水制乙烯催化性能得到改善,尤其低温催化活性提高,这主要归功于碱处理中介孔的形成和表面酸性的调变。     

碱处理制备介孔-微孔沸石分子筛的影响因素及其应用研究进展

综述了碱处理制备介孔-微孔沸石分子筛的影响因素,包括碱处理条件、沸石分子筛硅铝比和模板剂对碱处理脱硅形成介孔的影响。评述了碱处理所制备介孔-微孔沸石分子筛在应用方面所取得的进展,重点介绍了它们在烷基化、异构化、裂化和醇烃化等催化反应中的应用。通过碱处理引入介孔可极大地缩短分子在沸石微孔道中的扩散距离,从而增强表观催化反应活性及提高催化剂的稳定性。提出了今后研究的重点为：阐明碱处理引入介孔的形成机理和碱处理对分子筛骨架结构、酸性的影响,拓展碱处理制备介孔-微孔沸石分子筛的应用 范围。     

氢氧化钠改性丝光沸石吸附二氯甲烷的研究

采用NaOH溶液改性制备多级孔丝光沸石,通过改变NaOH溶液浓度调控沸石结构溶蚀程度,并采用X射线衍射、X射线荧光光谱、傅里叶红外光谱、场发射扫描电镜和N₂吸脱附方法考察碱改性作用对丝光沸石的影响,研究丝光沸石吸附二氯甲烷的性能。结果表明：使用适当浓度的NaOH溶液可以从丝光沸石骨架中抽离硅原子,引入介孔,并提高丝光沸石表面酸性密度,从而提升丝光沸石的吸附性能和二氯甲烷的扩散速率。NaOH溶液改性后的丝光沸石对二氯甲烷穿透吸附量提升了195.9%,扩散特性速率常数提升25.4%。     

新型高水热稳定性MOR/MCM-41复合分子筛的合成

以丝光沸石分子筛为硅铝源,通过碱液处理和表面活性剂的自组装作用,水热条件下合成了MOR/MCM-41复合分子筛。通过XRD、SEM、TEM、N2吸附/脱附和水热稳定性处理等手段对合成的复合材料进行了表征。结果表明,复合材料不仅保留了原丝光沸石晶体的规则形貌,同时兼具微孔分子筛MOR和介孔分子筛MCM-41的特征,且介孔(20~30 nm)在微孔分子筛中较均匀地分布。水热处理测试结果表明,MOR/MCM-41复合分子筛具有较高的水热稳定性,水热处理100 h后介孔结构依然存在。     

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。