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落葵提取物中皂甙含量的测定 总被引:1,自引:0,他引:1
采用香草醛-硫酸法测定落葵提取物(粗皂甙)中的皂甙含量,以齐墩果酸为标准品,用正交实验法确定香草醛-硫酸法显色反应的最优条件。结果表明,显色反应的最优条件是:反应温度为80℃,香草醛乙醇浓度为10%,硫酸浓度为60%。在此条件下测得落葵粗皂甙中的总皂甙含量为14.9%。 相似文献
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以环己酮为底物、30%H2O2为氧源,钨酸钠为催化剂,首次采用硫酸氢钾为酸性配体催化合成了己二酸。结果表明该反应体系具有成本低、无有害物排放、不易腐蚀设备、催化剂和酸性配体易分离回收并可重复使用等优点,硫酸氢钾是此反应体系具有应用开发前景的酸性配体。考察了催化剂用量、配体用量、反应原料用量、反应时间及催化剂重复使用性等因素对产物收率的影响,确定了适宜反应条件:n(环己酮):n(H2O2):n(钨酸钠):n(硫酸氢钾)=1:4.45:0.02:0.02,反应7h,己二酸收率达83.6%。实验还发现,采用硫酸氢钠、氨基磺酸及对甲苯磺酸为酸性配体适宜反应条件下收率分别为82.2%、81.5%和71.2%,收率均低于硫酸氢钾为酸性配体的产物收率。 相似文献
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葡萄籽中原花青素提取工艺研究 总被引:1,自引:0,他引:1
施立钦 《精细与专用化学品》2007,15(20):23-26
通过浸提的方法从葡萄籽中提取原花青素,考察了不同溶剂、浸提时间、浸提温度、乙醇体积分数和料液比等单因素对浸提效果的影响,确定了最佳的单因素水平。并通过正交实验,得出了原花青素提取的最佳工艺条件:乙醇的体积分数为70%,提取温度为50℃,料液比为1∶7(g/mL),提取时间为30min,提取次数为3次。 相似文献
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以邻甲苯胺、硫酸、亚硝酸钠为原料,采用重氮化-偶合反应方法制备邻氨基偶氮甲苯。分别考察了硫酸浓度、亚硝酸钠浓度、以及亚硝酸钠与邻甲苯胺的量比等因素对邻氨基偶氮甲苯收率的影响,同时考察了采用一定量回收邻甲苯胺对邻氨基偶氮甲苯收率的影响。结果表明:浓度为36%硫酸溶液、36%亚硝酸钠溶液以及亚硝酸钠与邻甲苯胺的量比为1.1∶1条件下,邻氨基偶氮甲苯的收率达到87%的最高值,纯度为95%;在偶合反应中添加30%~50%的回收邻甲苯胺,产物收率在77%左右。 相似文献
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采用食物来源的茶多酚为亲核试剂对肉桂中原花青素多聚体(PPC)进行片段化反应,采用大孔吸附树脂HP-20对片段化反应产物进行分级处理,使低聚体从片段化反应产物中分离出来。以反应后低聚体含量和低聚体中原花青素含量为考察指标,通过单因素试验、正交试验考察了片段化反应时间、反应温度、盐酸体积分数和多聚体与茶多酚物料比对反应的影响。结果表明,各因素对反应的影响次序为:盐酸体积分数 > 多聚体与茶多酚物料比 > 反应温度 > 反应时间,片段化反应最佳条件为:反应温度为50 ℃、反应时间为60 min、盐酸体积分数为1%、多聚体与茶多酚物料比为1:1,在此条件下,得到片段化反应后低聚体含量为65.26%,低聚体中原花青素含量为75.28%。 相似文献
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对原花青素的提取及测定进行了系统研究。考察了料液比、乙醇浓度、提取温度、提取时间等因素对原花青素提取的影响,并通过正交实验确立了最适合的提取条件为:料液比为1∶6、乙醇浓度为60%、提取温度50℃、提取时间60 min。极差分析表明提取温度对原花青素提取影响最大,其次是乙醇浓度、提取时间和料液比。铁盐催化比色法系统考察了反应时间、反应温度、反应介质的种类、酸的种类、酸的浓度、金属离子的种类及Fe3+的含量等因素对吸光度的影响,确立最适测定条件为:以正丁醇及5 mL的浓盐酸的混合液作为反应介质,浓度0.415 mol/L的Fe3+作为催化剂,60℃下反应60 min,测得的吸光度最大。 相似文献
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M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
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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Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
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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Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US
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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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
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中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2009,37(3)
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
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中蓝晨光化工研究院《塑料工业》编辑部 《塑料工业》2007,35(3):1-25,67
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