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1.
为了考察了Mn与Zn摩尔配比以及不同碱金属盐修饰制得的锰锌复合氧化物催化剂对苯甲酸甲酯气固催化加氢合成苯甲醛反应活性和选择性的影响,在氢酯比为1.5的条件下,进行苯甲酸甲酯催化加氢反应,发现以5%LiCl修饰的活性组分负载量为25%、n(Mn)/n(Zn)为1.14的MnO-ZnO/γ-Al2O3催化剂,在常压、430℃、空时为1.84 h时,苯甲酸甲酯的转化率为97.71%,苯甲醛的选择性为84.80%.  相似文献   

2.
采用等体积浸渍法制备了MnOx/Al2O3催化剂,在固定床连续反应器上考察了MnOx负载量对苯甲酸加氢制备苯甲醛的催化性能的影响,采用TG-DSC、H2-TPR、NH3-TPD和CO2-TPD等手段对催化剂进行了表征,并与催化剂活性和苯甲醛选择性关联。研究表明,在常压、380℃、氢气空速为760 h-1、氢/酸物质的量比为68的条件下,锰负载量为10%~15%的催化剂苯甲酸转化率在92%以上,苯甲醛选择性接近90%。H2-TPR表明,苯甲酸加氢反应与催化剂的氧化还原性有很大的关联,催化剂表面氧空位增加对苯甲酸加氢反应有利。NH3-TPD和CO2-TPD表明催化剂的表面酸碱性对反应活性有很大影响,具有表面弱酸性和中等强度碱性的催化剂活性和苯甲醛选择性比较高。  相似文献   

3.
以浸渍法制备了多种以MnO2为活性组分的加氢催化剂,在固定床反应器上,进行了叔丁基苯甲酸甲酯气相加氢合成对叔丁基苯甲醛的实验。考察了反应温度、液时空速(LHSV)、气时空速(GHSV)以及金属离子掺杂对催化剂加氢合成叔丁基苯甲醛的影响。实验结果表明,加氢反应的最佳条件:反应温度为410~420℃,LHSV为0.4h^-1,GHSV为400h^-1。MnO2/γ—Al2O3催化体系中引入Zr可以提高了催化性能,反应转化率为86.32%,选择性为94.58%。  相似文献   

4.
以自制的镍基催化剂对乙基咔唑进行加氢性能研究。实验采用γ-Al2O3为载体,在乙二醇溶液中以水合肼为还原剂,制备了不同负载量的Ni/γ-Al2O3催化剂,采用X射线荧光分析、X射线衍射等检测手段对其表征,并在0.1 L的高压反应釜中对乙基咔唑进行催化加氢。实验表明:当Ni负载量为20%时,Ni/γ-Al2O3催化剂具有较优的催化性能;在反应温度200℃、反应压力6 MPa、负载量为20%的Ni/γ-Al2O3用量1.5 g的加氢条件下,10 g乙基咔唑可以加氢0.280 mol,吸氢转化率达91.2%。  相似文献   

5.
提出了苯甲酸甲酯气相原位加氢制苯甲醛的路线。在常压固定床反应器上研究了浸渍法制备的Cu-MnO/γ-Al2O3双功能催化剂催化苯甲酸甲酯气相原位加氢制苯甲醛的反应性能,考察了催化剂的组成、反应温度、进样速率、酯/醇/水摩尔比等因素对苯甲酸甲酯转化率和苯甲醛选择性的影响。在优化的反应条件(苯甲酸甲酯/甲醇/水摩尔比为0.5/40/40、反应温度为420℃、进样速率为0.1 ml•min-1)下,苯甲醛选择性可达到88.5%,苯甲酸甲酯的转化率为79.6%,且Cu-MnO/γ-Al2O3催化剂具有较好的稳定性。根据产物分布提出了苯甲酸甲酯原位加氢的反应机理。该反应体系不需要外部供应氢气,避免了氢气的生产和运输,简化了反应工艺。  相似文献   

6.
采用等体积浸渍法和脉冲电磁场辅助浸渍法制备了CoMo/γ-Al2O3催化剂,研究活性组分负载量及脉冲时间对催化剂催化噻吩加氢脱硫(HDS)性能的影响。结果表明,当Co-Mo/γ-Al2O3催化剂的MoO3负载量为载体质量的12%,CoO与MoO3的质量比为1∶6,脉冲处理时间为60 s时,活性最好,噻吩转化率可达91.49%。在适当强度的脉冲电磁场作用下,催化剂具有较大的比表面积和较好的孔结构。  相似文献   

7.
赵厚瑞  施岩  李鸿鹏  吉豪杰 《当代化工》2014,(5):704-706,711
采用原位还原技术制备出Ni2P/TiO2-Al2O3催化剂,以喹啉为模型化合物对催化剂的加氢脱氮性能进行评价。主要考察复合载体中不同钛铝配比、不同Ni/P摩尔比对催化剂活性的影响及确定活性组分Ni2P负载量,确定该加氢脱氮催化剂最佳制备方法为:当n(Ti)/n(Al)=1/4,Ni2P负载量25%(wt)。在压力为3 MPa,体积空速为3 h-1,氢油体积比为500,反应温度为360℃的条件下,催化剂的加氢脱氮活性最高,可达98%。  相似文献   

8.
脱氢芳樟醇选择性加氢合成芳樟醇   总被引:1,自引:0,他引:1  
杜宇  朱志庆 《广东化工》2010,37(3):115-116
研究制备了负载型双金属Pd-Bi/Al2O3催化剂,用于固定床中脱氢芳樟醇选择性加氢生成芳樟醇的反应。考察了催化剂中活性组分Pd的负载量,以及在不同反应温度下Pd与Bi的原子配比对反应活性和选择性的影响。实验结果表明,当催化剂中Pd负载量为0.6‰,Pd/Bi原子比为1,在反应温度90℃和反应压力1.5MPa时,反应转化率为95.7%,生成芳樟醇的选择性达到85.3%。  相似文献   

9.
采用浸渍法制备了负载型碘化钾催化剂,并通过二氧化碳、环氧丙烷和甘油合成甘油碳酸酯反应评价其催化活性,发现KI/γ-Al2O3具有最高的活性,甘油的转化率为58.5%,甘油碳酸酯的产率为54.6%。其中,不同比表面积的γ-Al2O3载体对于活性组分负载量具有一定的影响,通过BET、XRD法对催化剂进行了表征,进一步说明了大比表面积的γ-Al2O3载体有利于KI高度分散。实验考察了反应温度、反应物摩尔比、KI负载量对反应结果的影响,得到最佳实验参数为:反应温度130℃,环氧丙烷与甘油的摩尔比3∶1,KI负载量1.5 mmol/g。催化剂KI/γ-Al2O3经过5次使用后,甘油碳酸酯的产率仍在50%以上,具有较好的稳定性。  相似文献   

10.
采用原位还原技术制备TiO2-Al2O3复合载体负载活性组分Ni2P催化剂,以喹啉为模型化合物对催化剂的加氢脱氮性能进行评价。主要考察复合载体中不同钛铝配比、不同Ni/P摩尔比及活性组分Ni2P负载量、不同模板剂用量对催化剂活性的影响,确定制备复合载体最佳钛铝比n(Ti)/n(Al)=1/4;模板剂和钛酸四正丁酯最优摩尔比为0.2;在压力为3 MPa,体积空速为3 h-1,氢油体积比为500,反应温度为360℃的条件下,催化剂的加氢脱氮活性最高,可达98%。  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   

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17.
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   

18.
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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