SAPO分子筛及其应用

磷酸硅铝分子筛(SAPO)是由SiO2、AlO2-、PO2 三种四面体单元构成的微孔型晶体,其孔结构可通过改变不同的合成条件及硅含量来控制.由于骨架呈负电性,具有可交换的阳离子,同时呈现出质子酸性,因此SAPO分子筛被广泛用作吸附剂、催化剂和催化剂载体,是一种具有优异择形选择性、热稳定性和湿热稳定性的新型催化材料.     

磷酸硅铝分子筛的合成及其应用

磷酸硅铝(SAPO)分子筛是由PO4+、AlO4-及SiO2三种四面体单元构成的微孔型晶体.人工合成SAPO分子筛的方法主要是水热合成.采用不同的有机模板剂、混合物配比及pH值等因素会影响SAPO分子筛合成的结果.由于骨架呈负电性,具有可交换的阳离子,同时呈现出质子酸性,可以催化低碳物和甲醇的转化、烃类的异构化、烷基化以及汽车尾气净化等反应.SAPO分子筛还被广泛用作吸附剂和催化剂载体,是一种具有优异择形选择性、热稳定性和湿热稳定性的新型催化材料.     

SAPO系列分子筛催化剂应用于正构烷烃异构化的研究进展

磷酸硅铝分子筛SAPO是由PO_4、AlO_4和SiO_4三种四面体构成的三维骨架结构微孔型晶体,具有优异择形选择性、离子交换性、酸性可调性和水热稳定性等特殊性能,广泛用于裂解、烷基化、聚合、重整、加氢、脱氢和水合等反应。综述了SAPO系列分子筛在正构烷烃异构化反应中的应用。SAPO作载体比传统载体制得的催化剂活性高;SAPO-11负载的贵金属催化剂有较高的活性和异构选择性;小粒径SAPO系列分子筛负载的高比表面积、高活性、高稳定性和强抗中毒性能的非贵金属催化材料是异构化催化剂的研究热点。展望了SAPO系列分子筛的研究方向及应用前景。     

新型催化材料--SAPO分子筛

磷酸硅铝分子筛（SAPO）是由SiO2、AlO2^-、PO2^＋三种四面体单元构成的微孔型晶体,具有从六元环至十二元环的孔道结构,孔径在0．3nm～0．8mm,骨架呈负电性,具有可交换的阳离子,被广泛用作吸附剂、催化剂和催化剂载体,是一种具有优异择形选择性、热稳定性和湿热稳定性的新型催化材料。SAPO分子筛可呈现出由中强酸到强酸的催化性能,几乎可用于所有的烃类反应。     

SAPO合成因素的影响研究

磷酸硅铝分子筛(SAPO)作为新型的晶体分子筛,具有优异的性能,使得SAPO分子筛在许多烃类转化方面得到应用,在合成过程中受诸多因素的影响。介绍了SAPO系列分子筛的研究现状,总结了合成过程中SAPO的影响因素,并分别从原料及配比、晶化条件、介质、pH值、加料顺序等方面进行综述,改变任何一个影响因素对SAPO分子筛的种类、结晶度、晶貌、酸性、孔容、比表面积等都会产生一定影响。最后指出,提高烃类异构化反应的SAPO分子筛性能,需要对其酸性和孔道结构进行调节改性是急需解决的问题。     

由沸石纳米粒子自组装制备具有高催化活性中心和水热稳定的新型介孔分子筛材料

人们合成了一系列介孔分子筛材料,并发现它们在催化、吸附与分离以及化学组装制备先进材料和分子器件等方面具有很大的潜在应用价值.但是,介孔分子筛材料相对于微孔沸石分子筛存在着两个致命弱点:较低的水热稳定性和较不活泼的催化活性中心.这两个弱点大大地影响了介孔分子筛在催化反应中的广泛应用.本文系统地综述了最近几年利用沸石纳米粒子自组装制备具有高催化活性中心和水热稳定的介孔分子筛材料的研究进展.这包括利用硅铝沸石纳米粒子自组装制备具有强酸性和水热稳定的新型介孔硅铝分子筛材料,利用钛硅沸石纳米粒子自组装制备具有高催化氧化活性中心和水热稳定的新型钛硅介孔分子筛材料,以及利用含有不同杂原子的沸石纳米粒子自组装制备一系列水热稳定的新型介孔分子筛催化材料.     

分子筛材料制备及应用研究进展

分子筛是一类具有独特孔道结构的硅铝酸盐晶体,其具有比表面积大、催化性能好、孔道选择性高、热稳定性好等特点。此外,还有多种后处理方法可以对分子筛进行改性,从而扩大其应用范围。概述了分子筛的种类、用途以及改性方法,介绍了分子筛的各种制备方法,包括水热合成、气相转移、离子热合成、干粉体系合成法等,并对分子筛在环境保护、农业、生物医药、新型功能材料等领域的应用进行了综述。     

酸性组分对LCO改质催化剂反应性能的影响

借助XRD,IR,NH3-TPD、N2 物理吸附等分析手段对4种改性Y沸石进行了表征.考察了不同酸性组分对LCO加氢改质催化剂反应性能的影响,结果表明分子筛硅铝比高,晶形完整,水热稳定性好以及较高的酸强度和较高的B酸浓度有利于催化剂维持较高的催化性能.最终确定了一种晶形完整、耐氮能力强及酸性高的改性Y分子筛为LCO改质催化剂的主要酸性组分.     

MCM-22分子筛的合成研究进展

MCM-22分子筛是一种高硅铝比分子筛,具有独特的晶体结构、高孔容及微孔率、优良的水热稳定性能和酸性性能,在烃类催化裂化、甲苯岐化、芳烃芳构化和烷基化等反应表现出了优异的催化性能,因此引起了科研工作者的极大研究热情。本文综述了MCM-22分子筛的结构特征、合成的影响因素以及在催化反应上的应用。提出了目前MCM-22分子筛合成所存在的问题,并对其今后的主要研究工作进行了展望。     

高硅铝比小晶粒分子筛的合成及应用进展

小晶粒分子筛具有较大比表面积和短孔道,在炼油和石油化工反应中表现出优异的催化性能。分子筛晶粒越小,热稳定性和水热稳定性越差。结晶度相近的沸石分子筛结构稳定性主要受粒径和骨架硅铝比的影响。综述了小晶粒分子筛的合成方法,认为提高硅铝比可以提高小晶粒分子筛的热稳定性和水热稳定性。介绍了高硅铝比小晶粒沸石分子筛的制备及研究进展,认为高硅铝比小晶粒分子筛的合成仍是未来研究趋势。     

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。