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1.
以甲基丙烯酸缩水甘油酯(GMA)和甲基丙烯酸甲酯(MMA)的交联共聚微球GMA/MMA为基质,经过几步大分子反应在微球表面合成与固载了N-羟基邻苯二甲酰亚胺(NHPI),形成固载有NHPI的聚合物微球GMA/MMA-NHPI。将GMA/MMA-NHPI与Co(OAc)2组成共催化体系,用于分子氧氧化苯甲醇的反应过程。研究结果表明,GMA/MMA-NHPI与Co(OAc)2所构成的共催化体系在温和条件(65℃和常压氧气)下可有效地实现苯甲醇的分子氧氧化过程,将其深度氧化为苯甲酸,显示出较好的催化活性和高的选择性(苯甲酸的选择性为96%)。主催化剂GMA/MMA-NHPI固载的NHPI与助催化剂Co(OAc)2适宜的摩尔比为20:1;主催化剂所含NHPI的摩尔分数为底物的10%时催化剂的用量比较适宜。固体催化剂GMA/MMA-NHPI还具有良好的再循环使用性能。  相似文献   

2.
采用超声辅助浸渍法制备La-Cu-Fe/SiO2催化剂,考察稀土元素La对Cu-Fe/SiO2催化剂的催化性能影响。通过X射线衍射(XRD),氮气吸附-脱附,CO的程序升温脱附(CO-TBD),程序升温还原(H2-TPR)等测试技术对La-Cu-Fe/SiO2催化剂进行表征,并利用合成气制备低碳醇反应评价其催化性能。试验结果表明,Cu-Fe/SiO2催化剂加入稀土元素La后,有助于改善活性中心的分散程度,增大催化剂的比表面积,提高反应物CO的吸附浓度,减小活性中心的还原损失,从而促进C2 醇的生成,有效降低产物的甲醇含量。  相似文献   

3.
考察了N-羟基邻苯二甲酰亚胺与负载型铁氧化物相组合时催化氧化环己烷的效果以及可能存在的机理。用浸渍法制备了多种负载型铁氧化物催化剂,研究了用不同载体和不同铁来源制备的催化剂与N-羟基邻苯二甲酰亚胺共同催化氧化环己烷,比普通的三价铁盐与N-羟基邻苯二甲酰亚胺相组合催化氧化环己烷好。N-羟基邻苯二甲酰亚胺与Fe/ZrO2在 100 ℃和氧压0.6 MPa下反应6 h,环己烷转化率可达53%。通过穆斯堡尔谱图等实验手段提供的信息提出可能的催化机理, 负载型铁氧化物晶体缺陷产生的Fe4+是激发N-羟基邻苯二甲酰亚胺为PINO自由基的来源。  相似文献   

4.
宋华  穆金城  王登  李秀敏 《化工进展》2012,31(4):833-838
采用溶胶-凝胶法制备了W改性SiO2催化剂,并通过X射线衍射(XRD)、红外光谱(FTIR)、N2吸附(BET)、扫描电镜(SEM)等方法对催化剂进行表征。以苯并噻吩(BT)/石油醚模拟油为原料、H2O2为氧化剂,研究了催化剂催化氧化脱硫性能,考察了溶剂及用量、反应温度、氧化剂用量、催化剂用量、反应时间对苯并噻吩脱硫率的影响。结果表明,催化剂中W以WO3晶相存在,引入W后催化剂的比表面积有所降低。在模拟油原料20 mL、催化剂用量0.04 g、H2O2/S摩尔比8、乙腈/模拟油体积比0.3∶1、65℃下反应60 min时,模拟油脱硫率可达99.6%。  相似文献   

5.
以Zn-ZrO2/SiO2为催化剂,在微型固定床反应器中用甲醇直接非氧化脱氢制备无水甲醛,考察了催化剂组成、反应温度及质量空速对脱氢反应的影响。结果表明,在进料的甲醇体积分数为35%、反应温度为800 K、质量空速为35 mL/(g.s)的反应条件下,甲醇的转化率达到100%,甲醛的选择性达到63%。结合催化剂的活性评价及X射线光电子能谱、热重等技术显示,采用均匀沉淀法制备的Zn-ZrO2/SiO2催化剂,活性组分能均匀分散在载体上,且对甲醇的非氧化脱氢具有高效的催化作用。助剂ZnO的引入可以有效抑制反应过程中催化剂的烧结,极大程度地增强催化剂的稳定性。  相似文献   

6.
介绍了一种新型的负载型铜基催化剂,用于催化羟基新戊醛(HPA)低压下加氢合成新戊二醇(NPG),并在固定床连续反应装置上研究了不同助剂及反应条件对催化剂性能的影响。采用均匀沉淀法制备了四种助剂(Co、Mn、Ni、Zn)修饰的Cu/SiO2催化剂,其中Co修饰的Cu/SiO2催化剂,在压力0.10~0.62 Mpa、反应温度90℃、HPA质量分数11.24%、n(H2):n(HPA)=4:1和液时空速1.4 h-1的条件下,羟基新戊醛转化率大于99.0%,新戊二醇选择性接近100%。利用XRD、BET和TG表征了不同助剂修饰前后催化剂的物化特性。结果表明:经Co修饰后的催化剂并没有改变CuO的晶相结构,而且阻止了CuO晶粒生长,同时增强了活性组分和载体之间的相互作用。  相似文献   

7.
用NaBH4作还原剂,制备了中性氧化铝(n-Al2O3)负载的Pt-M(M=Fe,Co,Ni,Cu,Mn,Sn)双金属催化剂。考察了过渡金属及反应条件对Pt-M/n-Al2O3催化肉桂醛加氢制肉桂醇的影响。结果表明,Fe改性的Pt/n-Al2O3对催化肉桂醛加氢制肉桂醇具有较好的催化性能,当Pt-Fe/n-Al2O3(中性)催化剂中Pt、Fe的含量均为0.3%时,在70℃,2 MPa氢气条件下反应1.5 h,肉桂醛的转化率为100%,肉桂醇选择性高达84.8%。  相似文献   

8.
盛凤军 《江苏化工》2007,35(4):38-40
分别以廉价硅酸钠与正硅酸乙酯为硅源,通过复合模板剂制备了介孔二氧化硅,并利用吸附相反应技术合成了TiO2/SiO2复合催化剂。用X射线衍射(XRD)、红外谱图分析(FT-IR)等手段对其结构进行了表征,通过苯酚的羟基化反应考察了催化剂的催化性能。  相似文献   

9.
采用N-羟基-邻苯二甲酰亚胺(NHPI)和乙酰丙酮亚钴(Co(AcAc)_2)作催化剂,分子氧氧化β-紫罗兰酮一步反应制备4-氧代-β-紫罗兰酮,收率达70%。以~1H-NMR、~(13)C-NMR、GC-MS、IR、元素分析仪对其进行表征。  相似文献   

10.
负载型MoO3催化剂结构与催化酯化性能研究   总被引:1,自引:0,他引:1  
以SiO2和Al2O3为载体,采用等体积浸渍法制备了MoO3质量分数为1%~30%的负载型MoO3催化剂。采用X射线粉末衍射(XRD)、比表面积测定(BET)、程序升温脱附(NH3-TPD)等对催化剂的结构和性能进行了表征,以乙酸乙酯的合成为模型反应评价了催化剂的催化酯化性能。结果表明,MoO3/SiO2和MoO3/Al2O3催化剂对酯化反应具有较好的催化活性和选择性,对于MoO3/SiO2催化剂,适宜的MoO3负载量为5%。催化剂的多孔结构和弱酸中心有利于酯化反应的进行。  相似文献   

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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.  相似文献   

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14.
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.  相似文献   

15.
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.  相似文献   

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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.  相似文献   

19.
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.  相似文献   

20.
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。  相似文献   

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