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1.
以十二酸、异戊醇为原料,负载型纳米固体杂多酸为催化剂,甲苯作带水剂,合成了十二酸异戊酯,同时对影响酯化率的因素进行了考察,结果表明其优化工艺条件为:酸醇物质的量比为1:5,催化剂用量为铴,反应时间2h,反应温度115-124℃,酯化率可达98%。  相似文献   

2.
张富捐  盛淑玲 《河北化工》2006,29(2):21-21,53
以对甲苯磺酸为催化剂。通过水杨酸和异丁醇酯化反应合成水杨酸异丁酯。研究了各有关因素对产品酯化率的影响。实验结果表明:对甲苯磺酸是合成水杨酸异丁酯的良好催化剂,在酸醇物质的量比为1:1.8,催化剂用量为5%,甲苯10mL,反应时间6h,反应温度120-140℃的条件下。水杨酸异丁酯的酯化率可达84.2%。  相似文献   

3.
采用直接酯化法,以活性炭负载硫酸氢钠为催化剂,催化异硬脂酸、2-乙基己醇合成异硬脂酸异辛酯,讨论了酸醇物质的量比、反应温度、反应时间、催化剂用量等因素对酯化反应程度的影响。活性炭负载硫酸氢钠催化合成异硬脂酸异辛酯的最佳反应条件为:酸醇物质的量比为1∶1.45,反应温度为150℃,反应时间为6 h,催化剂用量为0.5%。在此工艺条件下,合成的异硬脂酸异辛酯酯化率高、颜色好、副反应少。  相似文献   

4.
牛梅菊  高太明  尹汉东 《塑料工业》2004,32(11):11-12,48
以固体超强酸SO4^2-/TiO2-Al2O3-SnO2为催化剂、葵二酸和正丁醇为原料合成了癸二酸二丁酯(DBS)。研究了反应时间、醇酸物质的量比、催化剂用量等对酯化率的影响。结果表明:最佳反应条件为以0.05mol葵二酸为基准,n(酸):n(醇)=1:4,催化剂0.5g,反应时间3.5h,此时酯化率达97.5%,产品质量分数大于98%;催化剂重复使用6次后,催化活性基本不变。  相似文献   

5.
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   

6.
在微波辐射条件下,以新型碳基固体酸为催化剂催化草酸分别与正丁醇、异丁醇、正戊醇、异戊醇的酯化反应。系统研究了微波功率、酸醇摩尔比、催化剂用量、反应时间等诸因素对酯化率的影响。实验结果表明:微波功率为500 W,在n(醇)/n(酸)=4.0︰1,催化剂用量占反应物料总质量的2.3%,反应时间为12 min条件下,不同草酸酯的酯化率均在95%以上。该固体酸重复使用多次,其催化活性基本不变。  相似文献   

7.
固体酸SO4(2-)/Nb2O5催化合成尼龙酸二异丁酯   总被引:6,自引:0,他引:6  
研究了SO4^2-/Nb2O5作为催化剂催化合成尼龙酸二异丁酯的反应。通过正交试验确定了最佳反应条件:酸醇物质的量比为1:2.5,催化剂为反应物总量的0.35%,反应回流2.0h,在此条件下酯化率可达97.8%。  相似文献   

8.
以癸二酸和乙二醇单丁醚为原料,用HZSM-5分子筛催化合成环保耐寒性增塑剂癸二酸二丁氧基乙酯。考察了催化剂的硅铝比、催化剂用量、带水剂用量、原料配比、反应时间对酯化率的影响。最佳工艺条件为:醇酸摩尔比为2.5∶1,催化剂用量为酸质量的5%,带水剂用量为酸质量的15%,反应时间为3.5 h,反应温度为170~200 ℃,该工艺条件下酯化率可达91.91%。经过5次使用后,酯化率仍在90%以上。同时建立了该酯化合成的表观动力学模型,得到反应速率方程为: 。  相似文献   

9.
稀土固体超强酸催化合成氯乙酸异丙酯   总被引:2,自引:0,他引:2  
用稀土固体超强酸催化氯乙酸和异丙醇合成氯乙酸异丙酯,研究了各种因素对酯化率的影响,确定了反应的最佳条件,酸醇摩尔比为1:3,反应时间为5h,催化剂加入量为酸质量的4%,反应温度为回流温度,酯化率可达90.6%。  相似文献   

10.
用活性炭负载磷钨酸作催化剂,高效合成了二甲基丙烯酸丁二醇酯。比较了三种不同的负载方法对催化活性的影响,筛选出活性最高的负载方法。考察了酯化反应条件对催化活性的影响,得出优化合成条件:n(酸)∶n(醇)=2.3∶1,催化剂用量为总反应物质量的2.5%,带水剂甲苯用量为25%,阻聚剂对苯二酚用量为0.25 %,反应温度(100~110) ℃,反应时间约为1.5 h,酯化率可达到95.0%,催化剂重复使用6次,酯化率仍保持在85.0%以上。  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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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   

15.
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   

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.
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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