首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
采用溶胶-凝胶法制备了Cu/Ni超细混合催化剂,并用于糠醛液相加氢制2-甲基四氢呋喃反应。考察了Cu/Ni摩尔比,Na2CO3溶液浓度等催化剂制备条件,以及合成反应中反应压力、反应时间、反应温度等反应条件对糠醛转化率和2-甲基四氢呋喃选择性的影响。结果表明:催化剂制备条件为Cu/Ni摩尔比为5/5,Na2CO3溶液浓度为1.0 mol/l;合成反应条件为反应压力8 MPa,反应时间3.5 h,反应温度180 ℃;产品经气相色谱检测分析,糠醛的转化率为100%,2-甲基四氢呋喃的选择性为64.52%。  相似文献   

2.
采用化学还原法制备了CoNiB非晶态合金催化剂,并用于糠醛液相加氢制糠醇反应。考察了Ni/Co摩尔比,NaBH4滴加速率等催化剂制备条件对催化性能的影响,以及反应压力、反应时间、反应温度等反应条件对糠醛转化率和糠醇选择性的影响。结果表明:最佳的催化剂制备条件是Ni/Co摩尔比为5/5,NaBH4滴加速率为2.6mL·min-1;最佳的反应条件为反应压力2MPa,反应时间3h,反应温度80℃。在此条件下糠醛的转化率为46.2%,糠醇的选择性为90.4%。  相似文献   

3.
以MCM-41为载体负载Na2CO3制备Na2CO3/MCM-41型酯交换催化剂,用于催化大豆油制备生物柴油。并研究了催化剂用量、反应物的摩尔比、反应温度和反应时间等因素对该反应的影响。结果表明,最佳反应条件是n(甲醇)∶n(大豆油)=16∶1,催化剂用量为大豆油质量的3%,反应温度为60℃,反应时间为3 h条件下,酯交换转化率可达35%以上。  相似文献   

4.
非晶态CoNiB能催化糠醛液相加氢制糠醇   总被引:1,自引:0,他引:1  
采用化学还原法制备了CoNiB非晶态合金催化剂,并用于糠醛液相加氢制糠醇反应。考察了Ni/Co摩尔比,NaBH4滴加速率等催化剂制备条件对催化性能的影响,以及反应压力、反应时间、反应温度等反应条件对糠醛转化率和糠醇选择性的影响。结果表明:最佳的催化剂制备条件是Ni/Co摩尔比为5/5,NaBH;滴加速率为2.6mL·min2;最佳的反应条件为反应压力2MPa,反应时间3h,反应温度80℃。在此条件下糠醛的转化率为46.2%,糠醇的选择性为90.4%。  相似文献   

5.
以正辛醇为原料,考察了催化剂载体种类、Cu O-Ni O负载量和n(Cu O)∶n(Ni O)摩尔比对Guerbet十六醇催化合成反应的影响,在此基础上,以优选的30%Cu O-Ni O/Ca CO3(Cu O-Ni O负载量,即Cu O与Ni O所占质量百分数,为30%;n(Cu O)∶n(Ni O)=1∶2)为催化剂,进一步优化了反应条件(反应温度、反应时间和催化剂用量)。结果表明,Cu O-Ni O/Ca CO3-KOH催化体系能有效地催化正辛醇合成Guerbet十六醇,在Cu O-Ni O/Ca CO3、KOH投料量分别为0.10%和3.0%(催化剂投料量为催化剂质量与正辛醇质量百分比)时,240℃下反应1 h,Guerbet十六醇的收率和选择性分别为83.5%和87.3%。  相似文献   

6.
采用浸渍法制备了CuNi/Al2O3催化剂,研究了Ni负载量、Cu负载量及n(Cu)/n(Ni)对催化剂上乙炔选择加氢活性和选择性的影响,以及催化剂的还原性能。结果表明:CuNi/Al2O3催化剂中Cu提高了Ni的还原性,使催化剂具有很高的活性及乙烯选择性。随Cu/Ni原子比的提高,催化剂的活性下降,选择性升高,当Ni的负载量为10%、n(Cu)/n(Ni)=0.5时,在反应温度为50℃、反应压力为0.2 MPa、原料气流量为45 mL/min及H2流量为1.5 mL/min的反应条件下,乙炔的转化率达88.98%,乙烯的选择性达74.01%,乙烯收率为65.86%。  相似文献   

7.
采用HTLcs前驱体制备的丙酮一步法制MIBK催化剂   总被引:3,自引:0,他引:3  
采用共沉淀法制备Cu Mg A1三元类水滑石,进而煅烧得到CuO MgO Al2O3催化剂用于丙酮加氢一步合成甲基异丁基酮(MIBK)反应。研究了催化剂活性组分配比及反应条件对转化率和选择性的影响,经筛选得到催化剂体系的最佳组成为:n(Cu)∶n(Mg)∶n(Al)=4∶16∶10,适宜的反应条件为:温度240℃,n(H2)∶n(丙酮)=2.5,液空速为4.8mL/h·g,在该条件下丙酮转化率达73.88%,MIBK选择性达55.23%。  相似文献   

8.
以Ni Cl2·6H2O、Na H2PO4·2H2O、Fe Cl3·6H2O、低品级羟基磷灰石(HAP)为原料,采用浸渍法和离子交换法制备Ni2P/Fe-HAP催化剂,研究了其催化苯酚选择性加氢制备环己酮的反应活性和选择性。考察了反应温度、反应压力、反应时间、催化剂质量、活性组分负载量、镍磷物质的量的比、焙烧温度、Fe3+浓度对反应活性和选择性的影响,并通过正交实验筛选出最佳反应条件。结果表明,在反应温度为150℃、反应压力为0. 5 MPa、反应时间为3. 5 h、催化剂质量为0. 3 g时,苯酚转化率为65. 73%,环己酮选择性达85. 47%。  相似文献   

9.
合成了四苯基铁卟啉并用于催化丙烯环氧化合成环氧丙烷,考察了共还原剂种类、催化剂浓度、共还原剂用量、反应时间、反应温度、反应压力对实验的影响。该反应适宜的条件为1.74×10~(-5)mol/L催化剂TPPFe~(Ⅲ)Cl;1.31×10~(-4)mol/L助催化剂3-吲哚乙酸;共还原剂丙烯醛,n(正丁醛)∶n(丙烯)=1∶1.2;溶剂二氯甲烷,n(二氯甲烷)∶n(丙烯)=15.45;反应温度98℃;反应压力1.65 MPa;反应时间1.8 h。在该条件下,丙烯的转化率为35.04%,环氧丙烷的收率和选择性分别达34.28%和97.83%。  相似文献   

10.
该文以类水滑石为前驱体经500℃焙烧得到铜镍基催化剂(Cu11.2Ni4.7-MgAlO)及相应的单组分铜基(Cu11.2-MgAlO)或镍基催化剂(Ni4.7-MgAlO),并采用X射线粉末衍射(XRD)、程序升温还原(H2-TPR)等技术对催化剂进行了表征.以糠醛液相加氢为探针反应,考察了3种催化剂的催化性能,并详细研究了催化剂还原活化温度、加氢反应温度、加氢压力、反应时间及催化剂用量等工艺条件对Cu11.2Ni4.7-MgAlO催化糠醛液相加氢反应的影响.结果表明,Cu11.2Ni4.7-MgAlO的催化性能均优于Cu11.2-MgAlO和Ni4.7-MgAlO;在最佳反应条件下,以Cu11.2Ni4.7-MgAlO为催化剂的糠醛转化率和糠醇选择性均可分别达到95.6%和93.1%,Cu11.2Ni4.7-MgAlO循环使用6次后,催化性能无明显下降,具有较好的稳定性.  相似文献   

11.
12.
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   

13.
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.
16.
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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号