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1.
研究了催化剂V2O5-P2O5/SiO22的制备,并考察了制备工艺条件及反应条件对该催化剂的性能的影响,解释和分析了催化剂的制备、组成及反应条件等因素对合成α-氯丙烯酸甲酯的影响。实验结果给出常压下合成α-氯丙烯酸甲酯的最佳催化剂条件和反应条件:催化剂V2O5-P2O5/SiO2,V/P摩尔比为1:2.8,浸渍时间3h,活化温度为450℃;在空速1200h^-1,反应温度300℃,氯乙酸甲酯/甲缩醛摩尔比为2.4:1的条件下,所得甲缩醛转化率为76.2%,α-氯丙烯酸甲酯的选择性为58.5%,收率为44.58%。  相似文献   

2.
谢颖  肖林久  王宜阳  邢志强 《当代化工》2005,34(2):130-132,136
研究了催化剂V2O5-P2O5/SiO2的制备,并对其结构、性能进行了表征。通过甲基丙烯酸甲酯的催化合成过程,对该催化剂的活性进行了考察。解释和分析了催化剂的制备、组成及反应条件等因素对其活性及甲基丙烯酸甲酯合成的影响。实验结果给出常压下气固相催化合成甲基丙烯酸甲酯效果较好的催化剂V2O5-P2O5/SiO2的制备条件:V/P摩尔比为1:2.8,活化温度为450℃,浸渍时间3h。实验结果还给出常压下催化剂V2O5-P2O5/SiO2催化合成甲基丙烯酸甲酯效果较优的反应条件:在空速1500h^-1,反应温度300℃,丙酸甲酯/甲缩醛摩尔比为1.6:1的条件下进行常压反应,所得甲缩醛转化率为86.7%,甲基丙烯酸甲酯的选择性为66.2%,收率为57.40%。  相似文献   

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以甲缩醛为原料合成聚缩醛二甲醚,考察了催化剂、反应温度、物料配比、反应时『司、搅拌转速等因素对反应的影响。结果表明:以树脂为催化剂,催化剂用量5、vt%左右,甲醛和甲缩醛的摩尔比为1.0~1.5:1,反应温度96~105℃,搅拌转速为600~800r/min,通入的N2初始压力0.8~1.0MPa。在此条件下反应4~6h,反应转化率达到65%左右,选择性为90%左右。  相似文献   

4.
陶再山 《塑料助剂》2007,(3):17-19,32
研究了以2,6-二叔丁基苯酚,丙烯酸甲酯。草酸二乙酯及乙醇胺为原料合成具有抗氧化及金属钝化双重功能的金属钝化剂Nangarz XL-1的合成工艺。考察了各步反应机理及影响因素。结果表明中间体(3,5-二叔丁基-4-羟基)苯基丙酸甲酯合成最佳条件为:丙烯酸甲酯与2,6-二叔丁基苯酚的质量比为1.10:1,丙烯酸甲酯加入方式为120℃滴加0.5h,在140℃下反应4h,产率96.5%;中间体N,N’-双(羟乙基)草酰胺合成最佳条件为:乙醇胺与草酸二乙酯物质的量比2:1,反应温度为112℃,产率95.5%;产品Nangarz XL-1合成的最佳条件为:反应温度180℃,反应时间4h,催化剂为有机锡,产率90.2%。用红外光谱和核磁共振氢谱表征了产品化学结构。  相似文献   

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用无机方法合成了钛硅分子筛催化剂TS-1,并优化了TS-1催化环己酮氨氧化反应的条件。结果表明:无机催化剂可以取代有机催化剂。物料比、溶剂以及温度都对氨氧化反应有很大的影响。其优化的反应条件:NH。酮摩尔比为2.00,H2O2酮摩尔比为1.50,溶剂用蒸馏水且H2O酮摩尔比为7.5,反应温度为74℃。  相似文献   

6.
气相催化氧化法烟酸的绿色合成研究   总被引:3,自引:0,他引:3  
以3-甲基吡啶为原料,用V2O5/TiO2系催化剂,采用气相氧化法一步合成烟酸。水与3-甲基吡啶分开进料,通入催化剂床层后混合进行反应。实验考察了V2O5/TiO2用量、助剂、反应温度、进水量及空速等因素对催化剂活性的影响。当V2O5负载量为25%,反应温度320~340℃,3-甲基吡啶空速0.15~O8h^-1,空气、水、3-甲基吡啶的进料摩尔比为110:100:1时,烟酸的产率达到90%以上。  相似文献   

7.
固体超强酸TiO2/SO42-催化合成α-萘乙酸甲酯   总被引:3,自引:0,他引:3  
马冰洁  唐洪波 《农药》2004,43(4):165-166
以固体超强酸TiO2/SO4^2-为催化剂,研究了α-萘乙酸与甲醇的酯化反应,探讨了催化剂种类、用量及活化温度等反应条件,发现固体超强酸TiO2/SO4^2-对α-萘乙酸与甲醇的酯化反应具有较高的催化活性,并使后处理简化。较佳反应条件为:α-萘乙酸与甲醇的摩尔比为1:5.3,固体超强酸TiO2/SO4^2-活化温度为450℃~500℃,活化时间3h,用量为α-萘乙酸用量的3%,反应时间6h,反应温度74.5℃~76℃。在试验筛选的最佳条件下,酯产率超过96%,精酯收率达83%。  相似文献   

8.
研究了利用Ando催化剂,由结构为二环的无环鸟苷(Acyclovir)合成一种结构是三环的三环嘌呤化合物,并考察了反应物摩尔比、温度及催化剂用量等因素对产物收率的影响,找出了最佳反应条件。最佳的反应条件为:反应物(无环鸟苷)α与(对甲氧基-α-溴代苯乙酮)b摩尔比为1:1.2;反应物a与催化剂摩尔比为6:1;c(5,9-二氢化-3-[(2-羟基乙氧基)甲基]-6-对甲氧基苯基-9-氧代-咪唑并[1,2-α]嘌呤)与催化剂摩尔比为8:1;反应温度为18~25℃。  相似文献   

9.
顾振鹏  王勇  张晓娜 《辽宁化工》2013,(11):1274-1275,1283
通过相转移催化法合成苯甲醚新工艺,苯酚钠与一氯甲烷在相转移催化剂催化下合成了苯甲醚。最佳的反应条件为:苯酚与氢氧化钠摩尔比为1:1~2,苯酚与-氯甲烷摩尔为1:1.2~3,反应温度70~80℃,压力1.0~2.0MPa,反应时间4~8h,相转移催化剂的用量为苯酚重量的0.01%,苯甲醚的收率可达95%以上。  相似文献   

10.
TiSiW12O40/TiO2催化合成乙酸正丙酯   总被引:3,自引:0,他引:3  
首次报道了以固载杂多酸盐TiSiW12O40/TiO2为多相催化剂,通过乙酸和正丙醇反应合成了乙酸正丙酯,并探讨了诸因素对产率的影响。实验表明:TiSiW12O40/TiO2具有良好的催化活性,醇酸物质的量比为1.60:1,催化剂用量为反应物料总量的1.0%,反应时间1.5h,反应温度90℃-92℃时,产率可达94.58%。  相似文献   

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Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.  相似文献   

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2008~2009年世界塑料工业进展   总被引:4,自引:1,他引:3  
收集了2008年7月~2009年6月世界塑料工业的相关资料,介绍了2008~2009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、环氧树脂、不饱和聚酯树脂)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   

15.
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   

16.
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   

17.
It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.  相似文献   

18.
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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