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1.
研究了对甲苯磺酸铜催化丙酸与乙醇的酯化反应,考察了醇酸摩尔比、催化剂用量、反应时间对酯化率的影响。实验结果表明,其较优条件为:丙酸0.1mol,醇酸摩尔比1.5∶1,催化剂用量1.8%(mol%)(基于丙酸的摩尔百分数),回流温度下反应2.0h,在此条件下酯化率可达93.6%。反应结束后对甲苯磺酸铜经过简单的相分离就可重复使用,无需再生,兼有均相和多相催化剂的优点。  相似文献   

2.
研究了邻甲苯磺酸铜催化苯甲酸和正丁醇的酯化反应,考察了催化剂用量、醇酸摩尔比、反应时间等因素对酯化率的影响;找到了较佳的反应条件:苯甲酸用量为O.167mol,醇酸摩尔比为1.2:1,催化剂用量为1.0%(以苯甲酸的摩尔分数计),反应时间为2.5h,环己烷用量为5mL,在此条件下酯化率可达97.4%。邻甲苯磺酸铜重复使用5次后.其催化活性无明显下降。  相似文献   

3.
对甲苯磺酸铜催化合成对羟基苯甲酸乙酯的研究   总被引:1,自引:0,他引:1  
邓斌  龙石红 《化工中间体》2007,(3):15-17,21
研究了以对羟基苯甲酸、乙醇为原料、对甲苯磺酸铜为催化剂、合成对羟基苯甲酸乙酯,并讨论了催化酯化的影响因素。实验结果表明,对甲苯磺酸铜是合成对羟基苯甲酸乙酯的良好催化剂,优化的反应条件为:对羟基苯甲酸用量为0.10mol,醇酸摩尔比为4:1,甲苯磺酸铜用量为2.2g,回流温度下反应4.0h,在此实验下酯化率可达94.3%。产品经傅立叶红外光谱仪及熔点仪表征,证实与目标产物完全一致。  相似文献   

4.
龙石红  邓斌 《工业催化》2007,15(4):42-44
以对甲苯磺酸铜作为合成邻苯二甲酸二丁酯的催化剂,考察醇酸物质的量比、催化剂用量和反应时间对酯化率的影响。实验结果表明,其较优条件为邻苯二甲酸酐0.05 mol,醇酸物质的量比=2.0∶1,催化剂用量为原料邻苯二甲酸酐物质的量的1.5%,回流温度下反应2.5 h,在此条件下酯化率可达98.5%。反应后对甲苯磺酸铜经过简单的相分离就可重复使用,无需再生,兼有均相和多相催化剂的优点。  相似文献   

5.
对甲苯磺酸铜催化合成丁酸异戊酯   总被引:6,自引:0,他引:6  
吴长增  宋晓平 《化学试剂》2005,27(11):691-692
研究了由对甲苯磺酸与氧化铜反应制得的对甲苯磺酸铜作为催化剂,合成丁酸异戊酯,其最佳反应条件为:醇酸物质的量比1.4:1.0,反应时间1.5h,催化剂用量0.2%(以丁酸的物质的量计),反应温度120~140℃,酯化率达到99%以上。对甲苯磺酸铜制备容易,使用后处理简单,可以重复使用。  相似文献   

6.
单体酸甲酯化后用气相色谱.质谱联用仪测定单体酸的主要组成,共鉴定出硬脂酸(32.72%)、十八烯酸(25.53%)、肉豆蔻酸(12.16%)、棕榈酸(8.51%)等15种物质。用单体酸为原料制备生物柴油的方法为:单体酸与甲醇在对甲苯磺酸催化作用下,进行酯化反应来获得脂肪酸甲酯。考察了甲醇与单体酸的摩尔比、催化剂浓度、反应时间以及反应温度对酯化率的影响。结果表明,最佳酯化反应条件为:醇酸摩尔比3:1,对甲苯磺酸用量6%,反应时间3h,反应温度60℃。在此条件下,单体酸酯化率达98%,实验所得生物柴油的主要性能指标符合ASTN质量标准,并接近O#柴油性质。  相似文献   

7.
谭志斗 《安徽化工》2003,29(4):23-24
用一水合硫酸氢钠催化硬脂酸与正己醇的酯化反应合成了硬脂酸己酯。考察了催化剂用量、醇酸摩尔比、反应时间对酯化反应的影响。在典型反应条件下(正己醇与硬脂酸摩尔比=1.5:1,0.6g催化剂/0.2mol硬酯酸,反应时间2.5h),转化率为99.64%,酯化率为99.55%,产品收率为99.66%。  相似文献   

8.
研究了丙酸与丁醇在壳聚糖硫酸盐催化剂作用下的酯化反应,考察了反应时间、催化剂用量、醇酸摩尔比等因素对丙酸丁酯酯化率的影响。实验结果表明反应的最佳条件为:丙酸用量为0.1mol,醇酸摩尔比为1.4,壳聚糖硫酸盐用量为1.2g,反应时间为1.5h,酯化率达97.2%,催化剂重复使用5次仍保持较高活性。无污染产生,具有绿色合成的特点。产品经折光率、红外光谱进行了表征。  相似文献   

9.
以新型离子液体N-甲基吡咯烷酮硫酸氢盐([Hnmp]HS04)为催化剂,己二酸和异辛醇为原料,环己烷为带水剂,对己二酸二异辛酯的酯化反应进行了研究,重点考察了醇酸摩尔比、催化剂用量、带水剂加入量、反应时间等因素对己二酸二异辛酯酯化率的影响。实验结果表明,N-甲基吡咯烷酮硫酸氢盐对合成己二酸二异辛酯有着良好的催化活性,当己二酸用量为0.1mol时,醇酸摩尔此为2.6:1,催化剂用量为己二酸物质的量的1.2%,带水剂环己烷为10mL,回流温度下反应时间120min,在此条件下,反应的酯化率可达99%以上,且催化剂重复使用6次仍保持较高活性。  相似文献   

10.
硫酸氢钠催化合成丁酸戊酯的研究   总被引:9,自引:0,他引:9  
杨树 《化学试剂》2002,24(3):177-178
利用硫酸氢钠作为酯化反应催化剂合成了丁酸戊酯,其最佳反应条件为:催化剂用量0.2g/0.1mol丁酸,醇酸摩尔比2:1,带水剂10mL,反应时间1.0h,丁酸的酯化率可达99.19%。该催化剂催化效果好,使用量少,酯化率高,环境污染小,价廉易得,极有应用价值。  相似文献   

11.
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   

13.
14.
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   

15.
16.
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   

17.
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   

18.
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   

19.
建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。  相似文献   

20.
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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