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多酚氧化酶催化单宁的氧化聚合反应研究 总被引:4,自引:0,他引:4
研究了多酚氧化酶催化单宁的氧化聚合反应情况,探索了反应条件及7种化合物对酶活性的抑制效果,,对产物进行了红外光谱和紫外光谱测试,相对粘度法测定了产物的分子量,结果表明,,反应的最佳条件是PH为5.29,温度为30℃,在所用抑制剂中,硫酸铜的抑制作用最强,与单宁酸的IR图相比,产物的-OH吸收带变窄,在1260cm^-1处吸收峰增强,而紫外吸收无变化,产物平均分子量为3541,说明多酚氧化酶能催化单宁的氧化聚合。 相似文献
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《生物质化学工程》2004,(3)
Z0 40 78 固定化多酚氧化酶催化高纯度茶多酚生产高纯度茶黄素的方法 公开号:CN 1 40 35 80A ,公开日:2 0 0 3.3.1 9 本发明包括将多酚氧化酶用包埋材料进行固定化,固定化的多酚氧化酶在一定的反应条件下,使高纯度的茶多酚氧化聚合生成高纯度的茶黄素,然后将茶黄素溶液用溶剂萃取,浓缩干燥,得到茶黄素含量75 %以上的高纯度茶黄素产品。本发明工艺步骤简单,设备投入少,既可以降低生产成本,由于多酚氧化酶得到固定化,因此酶促反应又可以连续化,可根据需要控制茶多酚的氧化程度和产品质量,尤其避免使用多种酸和碱等化学试验,是一种保护环… 相似文献
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用聚马来松香酰乙二胺-Cu(Ⅱ)固定化香蕉多酚氧化酶催化降解废水中的2,4-二氯苯酚(DCP),探讨了影响反应的几种因素.结果表明,固定化香蕉多酚氧化酶催化降解反应的最佳pH为6.0,最佳降解温度为40℃;该固定化酶连续降解2,4-二氯苯酚6次后仍能保持19%的降解率. 相似文献
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聚马来松香酰乙二胺-Cu(Ⅱ)配合物的合成及在固定化酶中的应用 总被引:1,自引:0,他引:1
介绍了聚马来松香酰乙二胺-Cu(Ⅱ)高分子配合物的制备和固定化香蕉多酚氧化酶的方法,测定了固定化香蕉多酚氧化酶的活性和米氏常数,研究了温度和pH值对固定化香蕉多酚氧化酶催化活性的影响及固定化香蕉多酚氧化酶的重复催化活性。结果表明,聚马来松香酰乙二胺-Cu(Ⅱ)高分子配合物,是香蕉多酚氧化酶的良好固定化载体,固定化香蕉多酚氧化酶的米氏常数Km=4.56×10-3mol.L-1,小于天然香蕉多酚氧化酶的米氏常数(1.95×10-2mol.L-1),固定化香蕉多酚氧化酶的耐热性和耐酸碱性均优于天然香蕉多酚氧化酶,并有一定的重复使用性。对香蕉多酚氧化酶的固定化方式和固定化香蕉多酚氧化酶的催化反应机理也进行了初步探讨。 相似文献
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介绍了聚马来松香酰乙二胺-Cu(Ⅱ)高分子配合物的制备和固定化香蕉多酚氧化酶的方法,测定了固定化香蕉多酚氧化酶的活性和米氏常数,研究了温度和pH值对固定化香蕉多酚氧化酶催化活性的影响及固定化香蕉多酚氧化酶的重复催化活性.结果表明,聚马来松香酰乙二胺-Cu(Ⅱ)高分子配合物,是香蕉多酚氧化酶的良好固定化载体,固定化香蕉多酚氧化酶的米氏常数Km=4.56×10-3 mol·L-1,小于天然香蕉多酚氧化酶的米氏常数(1.95×10-2mol·L-1),固定化香蕉多酚氧化酶的耐热性和耐酸碱性均优于天然香蕉多酚氧化酶,并有一定的重复使用性.对香蕉多酚氧化酶的固定化方式和固定化香蕉多酚氧化酶的催化反应机理也进行了初步探讨. 相似文献
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《化学反应工程与工艺》2015,(4)
采用茂金属催化体系Ph_2C(Cp-9-Flu)ZrCl_2/C_6H_5NH(CH_3)_2B(C_6F_5)_4/Al(~iBu)_3催化1-癸烯聚合,考察了催化剂浓度、Al和Zr以及有机硼化物和Zr物质的量之比、反应温度和反应时间等工艺条件对产物的影响,并采用核磁共振对其产物与1-癸烯在Ph_2C(Cp-9-Flu)ZrCl_2/MAO催化下聚合产物的结构进行了分析比较。结果表明:在Zr和1-癸烯物质的量之比为10×10~(-5),硼化物和Zr物质的量之比为1.5,Al和Zr物质的量之比为100,反应温度为60℃的条件下,反应时间120 min,1-癸烯的转化率为93.6%,运动黏度(100℃)为3 684 mm~2/s,黏度指数为367,数均分子量为2.9×10~4,分子量分布为1.85;聚合时单体主要进行1,2插入,产生亚乙烯基端基。 相似文献
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人参皂苷Rb1是人参中的主要皂苷之一,但人体吸收量极少,而其衍生物Rg3、Rk1、Rg5却易于人体吸收,但其制备和分离成本较高。针对以上问题将人参皂苷Rb1在50%乙醇水溶液体系和无水乙醇体系中进行催化条件的优化,并分析其产物。实验发现,通过对金属离子催化效果的筛选,选取NbCl5为反应催化剂;在50%乙醇水溶液体系中最优条件下反应,Rg3得率为18.29%;在无水乙醇体系中最优条件下反应,Rg3得率为49.45%。根据两组反应产物的对比,推测在50%乙醇水溶液体系反应时,水可能供给电子基团,并生成更多水合化合物即20(S)-25-OH-Rg3和20(R)-25-OH-Rg3;在无水乙醇体系反应时,电子基团可能无法供给,形成双键,生成其他化合物即Rk1和Rg5。该发现为金属离子催化人参皂苷以制备稀有人参皂苷的方法奠定了理论基础。 相似文献
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茂金属催化体系具有超高活性和单一活性中心,是催化α-癸烯聚合的理想催化剂。用茂金属催化体系rac-Et(1-Ind)2Zr Cl2/MAO对1-癸烯聚合制备高粘度润滑油基础油进行了研究,提出了反应体系可能的聚合机理。考察了催化剂浓度、Al和Zr物质的量之比、反应温度和反应时间对聚合产物性能的影响。结果表明,在Zr和1-癸烯物质的量之比为8×10-5,Al和Zr物质的量之比为100,反应温度为50℃,反应时间为60 min时,1-癸烯的转化率为91.6%。聚合产物的整体性能较为优异,运动粘度(100℃)为393.9 mm2/s,粘度指数为271,数均分子量为9 091,分子量分布为1.691 3。 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