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1.
钨酸钠催化环己酮清洁合成己二酸的研究   总被引:1,自引:0,他引:1  
研究了Na2WO4·2H2O/H2O2(H2O2浓度为30%)体系催化氧化环己酮制取己二酸的反应。发现配体种类、用量、反应时间、催化剂的用量、双氧水的用量是合成己二酸的主要影响因素。通过一系列实验优选出磺基水杨酸为配体,采用正交设计考察了诸主要因素对己二酸收率的影响,确定n(环己酮)=100mmol时最佳的己二酸收率水平组合为:双氧水量54.5ml,n(催化剂)∶n(磺基水杨酸)=2∶1、催化剂量2.5mmol、反应时间7h。  相似文献   

2.
清洁催化氧化环己醇合成己二酸   总被引:14,自引:3,他引:14  
王艳丹  姜恒  宫红  苏婷婷 《化学世界》2002,43(9):484-486
以浓度为 30 % (质量分数 )过氧化氢为氧源 ,研究 Na2 WO4· 2 H2 O催化氧化环己醇制备己二酸反应中的配体效应。在大多数情况下配体的酸性越强 ,己二酸的分离产率越高。尽管一些酚类配体酸性较弱 ,但己二酸的分离产率仍有所提高 ,表明除了配体的酸效应外 ,还存在配体的配位效应。从邻苯二酚和对苯二酚的实验结果来看 ,反应可能是通过络合催化反应机理完成的。同时也考察了配体的用量和反应时间对反应的影响  相似文献   

3.
采用水热法制备了锡掺杂钨基催化剂SnO2/WO3,用于催化双氧水氧化环己酮合成己二酸,考察了催化剂用量、30%H2O2用量、反应时间、酸性配体及催化剂重复使用性等因素对己二酸收率的影响。结果表明,催化剂制备条件为n(W)∶n(Sn)=1.8∶1,500℃焙烧4 h。当反应条件为:100 mmol环己酮,1.0 g催化剂SnO2/WO3,50 mL 30%H2O2,反应5 h,己二酸收率78.4%。SnO2/WO3催化H2O2氧化环己酮合成己二酸,反应时间短,操作方便,具有较为理想的催化活性及重复使用性。  相似文献   

4.
清洁催化氧化苯甲醇合成苯甲醛新途径   总被引:1,自引:0,他引:1  
以30%的双氧水为氧源,Na2WO4·H2O为催化剂,在酸性配体存在而无任何溶剂和相转移催化剂的条件下,清洁催化氧化苯甲醇合成苯甲醛。研究了不同配体及其用量对反应的影响。  相似文献   

5.
杨一可  王皓  周慧  陈丹云 《应用化工》2011,40(8):1340-1342
以30%H2O2为氧源,NaHSO4.H2O、KHSO4为酸性配体,磷钨酸为催化剂催化氧化环己酮合成了己二酸。考察了催化剂用量、H2O2用量、酸性配体用量、反应时间以及催化剂重复使用性等因素对己二酸收率的影响。结果表明,磷钨酸在反应体系中有良好的催化活性,并且具有操作方便,条件温和等优点。适宜反应条件为n(环己酮)∶n(磷钨酸)=1∶0.002(摩尔比),硫酸氢钠0.1 g,30%H2O245 mL,回流反应6 h,己二酸收率66.7%;以KHSO4为酸性配体时,己二酸的收率可达71.2%。  相似文献   

6.
过氧化氢催化氧化苯甲醇制苯甲酸   总被引:7,自引:0,他引:7  
以质量分数为 30 %的过氧化氢 (H2 O2 )为氧源 ,探讨了Na2 WO4·2H2 O催化氧化苯甲醇制苯甲酸反应中酸性添加物的影响 ,在大多数情况下 ,酸性越强 ,苯甲酸的收率越高。用NaHSO4·H2 O作酸性添加物 ,对反应条件的优化研究表明 ,氧化反应的最佳条件为n(苯甲醇 )∶n(Na2 WO4·2H2 O)∶n(NaHSO4·H2 O)∶n(H2 O2 ) =10 0∶1∶1∶30 0 ,回流 7h ,苯甲酸收率达 82 .7%。  相似文献   

7.
磷钨酸催化过氧化氢氧化环己酮/环己醇合成己二酸   总被引:3,自引:0,他引:3  
在无溶剂、无相转移催化剂条件下,用钨酸钠或磷钨酸为催化剂,30%过氧化氢作氧源,在一定温度下可以将环己酮或环己醇,环己酮混合物高产率地氧化成己二酸。讨论了30%过氧化氢的量、反应时间、反应温度、催化剂用量、醇酮比和草酸对己二酸产量的影响。结果表明:反应温度为90℃,30%H2O2为0.4mol,草酸作酸性配体,钨酸钠催化氧化环己酮反应12h,制得的己二酸的最大产率仅为71.8%。而磷钨酸作催化剂反应8h,己二酸的最大产率高达95.1%。同时,不用酸性配体,磷钨酸对环己酮或环己酮,环己醇混合液也表现出很高的催化活性,在优化条件下己二酸产率可达87.5%或82%。  相似文献   

8.
WO3催化H2O2氧化环己醇合成己二酸   总被引:1,自引:0,他引:1  
以WO3为催化剂,H2O2氧化环己醇合成己二酸。探讨了催化剂用量、H2O2用量、反应温度和时间等条件对反应的影响。优化条件:n(环己醇)∶n(H2O2)∶n(WO3)=100∶600∶4、反应温度100℃、反应时间6h。己二酸分离收率达67.6%,纯度99.8%;催化剂重复使用5次后,己二酸收率仍可达60.2%。  相似文献   

9.
在无有机溶剂、无相转移剂的条件下,以E(H2O2)=30%为氧源,采用原位合成的Na2WO4/1,2,3,4-丁烷四羧酸/H2O2过氧钨酸络合物为催化剂,催化氧化环己烯合成己二酸。考察了酸性配体1,2,3,4-丁烷四羧酸的用量、反应温度和反应时间对反应的影响。当n(1,2,3,4-丁烷四羧酸):n(Na2WO4)=4:1、n(Na2WO4):n(环己烯):n(H2O2)=1:40:176、水浴控制温度(70~90℃)时,反应8h,己二酸分离产率高达85.1%。催化剂重复使用至第5次,己二酸产率仍分别可达80.4%(回流控温)和80.2%(水浴控温70~90℃)。  相似文献   

10.
在无溶剂、无相转移催化剂条件下,用钨酸钠或磷钨酸为催化剂,30%过氧化氢作氧源,在一定温度下可以将环己酮或环已醇/环己酮混合物高产率地氧化成己二酸.讨论了30%过氧化氢的量、反应时间、反应温度、催化剂用量、醇酮比和草酸对己二酸产量的影响.结果表明反应温度为90℃,30%H2O2为0.4 mol,草酸作酸性配体,钨酸钠催化氧化环己酮反应12 h,制得的己二酸的最大产率仅为71.8%.而磷钨酸作催化剂反应8 h,己二酸的最大产率高达95.1%.同时,不用酸性配体,磷钨酸对环己酮或环己酮/环己醇混合液也表现出很高的催化活性,在优化条件下己二酸产率可达87.5%或82%.  相似文献   

11.
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   

12.
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   

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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   

18.
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   

19.
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   

20.
Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.  相似文献   

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