非水解溶胶-凝胶过程制备锡/硅复合氧化物

以无水四氯化锡和正硅酸乙酯为前驱物、环己烷为溶剂,在无氧无水条件下采用非水解溶胶-凝胶过程制备了锡/硅复合氧化物,并对其进行了表征分析。结果表明,在原料Sn/Si摩尔比为1∶2、反应温度为30℃、焙烧温度为500℃时,所得复合氧化物的产率为31.3%,Sn/Si摩尔比为7.4∶1,粒径10nm左右,比表面积22.58cm2.g-1,平均孔径14.3nm,比孔容0.047cm3.g-1,主要为颗粒堆积孔;复合氧化物的主要组成为无定形氧化硅和氧化锡晶体,在焙烧温度达到500～600℃时仍有Sn-O-Si杂键存在。     

氧化硅改性二氧化钛催化乙苯脱氢制苯乙烯

通过溶胶凝胶法制备了二氧化钛、二氧化硅和钛硅复合氧化物催化剂,并通过BET、SEM对催化剂结构进行表征。结果表明:与TiO_2相比,加入二氧化硅合成Ti-Si氧化物比表面积明显增大,提高了乙苯脱氢合成苯乙烯性能。在600℃下,乙苯的转化率和苯乙烯选择性达到50.1%和93.4%。     

Ce-Zr-V-O复合氧化物对二氯甲烷催化燃烧性能

用共沉淀法制备不同铈锆比及V掺杂量的Ce-Zr-V-O复合氧化物催化剂,在常压固定床反应器上对复合氧化物催化剂用于二氯甲烷催化燃烧的活性进行评价,采用BET、XRD、XPS和H₂-TPR等方法对复合氧化物催化剂进行表征。结果表明,V与Ce-Zr形成了Ce-Zr-V-O固溶体,V掺杂提高了催化剂的比表面积和孔径,形成了更多的晶格缺陷和活性中心,使催化剂具有更高的催化活性和稳定性。n(Ce)∶n(Zr)∶n(V)=7∶3∶0.5时,Ce_0.7Zr_0.3V _0.05 O _2-λ催化剂活性最好,小于300 ℃,连续反应200 h,二氯甲烷转化率大于98%。     

硅源对无定形硅铝物化性能的影响

以硅溶胶和九水硅酸钠为硅源,九水硝酸铝为铝源,采用分步沉淀法制备一系列不同硅铝比的无定形硅铝,通过XRD、BET和NH₃-TPD等考察硅源对无定形硅铝物化性能的影响。结果表明,以九水硅酸钠为硅源制备的无定形硅铝比表面积和酸性均明显优于以硅溶胶为硅源制备的无定形硅铝;以九水硅酸钠为硅源,在SiO2质量分数为55%时,该无定形硅铝呈现出最大酸量和高的比表面积,作为性能优异的催化材料将具有良好的应用价值。     

制备条件对非负载Ni-Mo复合氧化物催化剂加氢脱氧性能的影响

以柠檬酸为络合剂,采用溶胶-凝胶法制备了非负载Ni-Mo复合氧化物催化剂,用N2吸附-脱附、XRD、SEM等手段对催化剂进行了表征.在连续流动固定床反应器上,以乙酸为探针分子考察了不同溶液pH值和溶剂量制备催化剂对催化加氢脱氧性能的影响.结果表明:溶胶-凝胶法制备的催化剂具有较高的比表面积和双介孔结构:主要以复合氧化物NiMoO4的形式存在;改变溶液的pH值和溶剂量,对催化剂的比表面积有一定影响.在初始溶液pH=1、溶剂量855 mL-(mol(Ni+Mo))-1的条件下制备的催化剂具有较优异的加氢脱氧活性,在0.3 MPa,250℃,液时空速2h-1的条件下,催化剂催化乙酸加氢脱氧的转化率和脱氧率分别达到99.9％和98.9％.     

超疏水金红石型纳米钛硅复合氧化物的制备与表征

以正硅酸乙酯为硅源、钛酸异丙酯为钛源,采用改进的溶胶-凝胶法制备了不同钛硅摩尔比的复合气凝胶,在不同温度下进行煅烧,得到金红石型钛硅(TiO_2-SiO_2)复合氧化物纳米颗粒,然后通过三甲基氯硅烷(TMCS)改性,制得超疏水金红石型TiO_2-SiO_2纳米材料。探讨了钛硅摩尔比和煅烧温度对钛硅复合氧化物纳米颗粒晶型的影响,并通过XRD、XPS、BET、SEM和FTIR等手段对产物进行了表征,采用水接触角测试(WCA)对纳米材料改性后的疏水性能进行了表征。结果表明:当钛硅摩尔比为5:1时制得的气凝胶在1100℃煅烧及TMCS改性后,所制备的超疏水金红石型纳米钛硅复合氧化物的比表面积大,疏水性能优异,其比表面积达348 m~2·g~(-1),水接触角达到154.7°,在构建具有纳微分层结构的外墙装饰材料的面漆方面具有潜在的应用前景。     

SiO_2-CuO复合氧化物催化氧化脱除苯并噻吩性能的研究

采用溶胶-凝胶法制备了SiO_2-CuO复合氧化物,通过X射线衍射(XRD)、扫描电镜(SEM)、N2吸附(BET)等表征手段对试样进行了表征。以石油醚为溶剂,配制500 mg/L(以S计)的苯并噻吩(BT)模拟原料油,以SiO_2-CuO复合氧化物为催化剂,考察了催化剂用量、氧化剂H_2O_2用量、溶剂用量、反应温度、反应时间等因素对脱硫率的影响。研究结果表明,SiO_2-CuO复合氧化物呈片状,粒径在0.5~7.0μm,复合氧化物中的Cu以CuO形式存在,其比表面积低于SiO_2。在原料油10 m L,催化剂0.05 g,氧化剂H2O20.1 m L,乙腈与原料油体积比0.3∶1,反应温度65℃,反应时间60 min等最佳反应条件下,BT脱除率达到64.6%。     

直接法合成三乙氧基硅烷

在铜系复合催化剂存在下,采用乙醇与硅直接反应,得到以三乙氧基硅烷为主的反应液;将反应液进行减压蒸馏,收集25~45℃/2~5 k Pa下的馏分,产品纯度达到98%,总收率达80%。研究了硅粉活化时间及粒径、催化剂种类、溶剂种类对硅粉转化率和三乙氧基硅烷选择性的影响。结果表明,最佳工艺条件为:溶剂选择聚乙氧基硅烷(聚合度3~5),催化剂为无水氯化亚铜和双二乙基磷酸铜质量比1∶1的混合物,硅粉不经活化直接使用且粒径选择300~500目。     

氟化铵对纳米金红石型钛硅复合氧化物表面改性研究

以硫酸氧钛为钛源、硅酸钠为硅源,采用改进的水解沉淀法制备了纳米金红石型钛硅复合氧化物(TiO_2-SiO_2),以氟化铵(NH_4F)为表面改性剂,采用水热法在不同溶剂中对TiO_2-SiO_2进行改性,并通过X-射线衍射仪、傅里叶红外光谱仪、扫描电镜、原子力显微镜和接触角测量仪等,研究了不同溶剂对改性效果的影响。结果表明,以异丙醇为溶剂进行NH_4F改性时,由于表面Si-F键的形成、异丙醇表面自组装和表面微纳分层粗糙结构的形成等因素的协同作用,改性后的纳米金红石型TiO_2-SiO_2比表面积大,具有良好的表面性能,其比表面积达332 m2/g,水和二碘甲烷接触角分别达到147.1°和147.2°。     

介孔铈锆氧化物的制备及表征

为了探讨催化剂的活性氧储量与催化剂组成和结构的关系,以Ce~(4+)、Zr~(4+)混合液为基本原料,NaOH溶液为沉淀剂,CTAB为模板剂,制备了Ce~(4+)与Zr~(4+)比例不同的系列铈锆复合氧化物,通过BET、H_2-TPR和XRD对制备的铈锆复合氧化物进行了表征。结果表明,Ce/Zr≤2/3的铈锆复合氧化物具有四方相结构特征,Ce/Zr=1的铈锆复合氧化物具有立方相结构特征;都是典型的介孔材料,有高的比表面积,最大值达到185.7 m~2/g;程序升温测试表明,铈锆复合氧化物在450℃和650℃附近有两个耗氢还原峰,分别对应于表面Ce~(4+)的还原和体相Ce~(4+)的还原;活性氧储量0.148～0.84 molO_2/mol(Ce+Zr),具有良好的可逆吸氧和释氧性质;活性氧储量不仅与材料的组成有关,也与材料的晶体结构有关,与材料的比表面积成正比。     

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。