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以油茶饼粕为原料,采用乙醇提取-丙酮沉淀法对茶皂素进行提取分离。以茶皂素纯度和得率为考察指标,对乙醇体积分数、液料比、提取温度、提取时间、提取次数、提取液浓缩程度和丙酮用量等工艺参数进行了单因素优化。结果表明:体积分数95%的乙醇为提取溶剂,乙醇与预处理过的油茶饼粕液料比为9:1(mL:g),提取温度为70℃,提取时间为4 h,提取次数为2次,提取液浓缩至刚好有固体析出,丙酮用量为4倍浓缩液体积量时提取分离效果较佳,得到的茶皂素纯度为85.17%,得率为9.82%。不同溶剂打浆对产品纯化效果的比较发现:丙酮、乙酸乙酯、无水乙醇、体积分数95%的乙醇作为打浆纯化溶剂用于提高茶皂素纯度效果均不明显。 相似文献
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通过离子交换技术对衬底表面改性,然后喷墨打印掩膜图形,在聚酰亚胺衬底两面分别制备了银叉指电极和加热电阻.通过调节电阻加热器两端的直流偏压,实现25 ℃~280 ℃的控温加热.集成的加热器具有双重功能:纳米ZnO敏感薄膜原位沉积和高温检测.结果表明,该传感器对丙酮气体的灵敏度随温度单调增加(<150 ℃).此外,加热器促进了ZnO敏感薄膜表面丙酮气体分子的解吸,缩短了传感器响应和恢复时间,并减小了初始电阻的漂移.此外,在丙酮检测中,加热器能有效地减少湿度干扰. 相似文献
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Volatiles from hosts, non-hosts, interspecifics, and conspecifics of the Asian larch bark beetle, Ips subelongatus Motsch., were analyzed using both gas chromatographic-electroantennographic detection (GC-EAD) and gas chromatography/mass
spectrometry (GC-MS) techniques, and field trapping bioassays in Inner Mongolia, China. GC-EAD experiments indicated that
I. subelongatus antennae (both sexes) strongly responded not only to the major male-produced conspecific components, ipsenol, and ipsdienol,
but also to other bark beetle compounds (cis-verbenol and verbenone), host monoterpenes (α-pinene, β-pinene, and para-cymene) from Larix sp. logs, and non-host leaf (green leaf volatiles and geranyl acetone) and bark (C8-alcohols and trans-conophthorin) volatiles. Repeatable EAD responses were also found to two compounds from hindgut extracts that are undetectable
by GC. One of these minor compounds was identified as amitinol. Field trapping experiments showed that the EAD-active, major
male-hindgut component, racemic ipsenol, is the only individual compound that significantly attracted both sexes of I. subelongatus, whereas all other compounds, including previously reported pheromone components of European Ips cembrae, ipsdienol and 3-methyl-3-buten-1-ol, were unattractive. Ipsdienol, 3-methyl-3-buten-1-ol, or their binary blend had no synergistic
or antagonistic effects on I. subelongatus attraction when combined with ipsenol, whereas cis-verbenol (a synomone) and verbenone (the antiaggregation semiochemical) inhibited its attraction to the ipsenol-containing
attractive blend. A mixture of three EAD-active host monoterpenes, α-pinene, β-pinene, and para-cymene, was unattractive,
but interrupted the pheromone response of I. subelongatus. Geranyl acetone, one of the strong EAD-active non-host volatiles also significantly reduced the number of I. subelongatus captured in traps baited with ipsenol-containing attractive blend. Our results add support to the recent phylogenetic finding
that European and Asian larch bark beetles should be regarded as two distinct species: I. cembrae infecting larch in Europe and I. subelongatus infesting larch in Asia. 相似文献
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原醋酸回收系统脱除丙酮的丙酮汽提塔效率很低,损失大量己烷。经改造后的脱丙酮系统脱丙酮的效率提高,己烷损失减少。每年可节约成本40多万元,延长了设备的使用寿命。介绍了对丙酮汽提塔系统的工艺改造过程。 相似文献
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The effect of chemisorbing water on three catalysts previously evaluated in the acetone condensation reaction has been studied.
The active sites in that reaction are Lewis acid sites present either on the surface of alumina or of nonframework alumina
in zeolites. These sites are poisoned by water and the reaction rate decreases at the pace of the loss of Lewis sites. The
stoichiometry of the poisoning reactions is one water molecule per site on alumina and two water molecules per site on nonframework
alumina.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献