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31.
2,3-戊二酮是一种奶香型食用香料,以经典的亚硝化法合成2,3-戊二酮,即以2-戊酮为原料,使用亚硝酸异戊酯为亚硝化试剂,在浓盐酸存在下进行亚硝化反应,生成3-肟-2-戊酮,再经过水解得2,3-戊二酮,总反应得率达48.2%。 相似文献
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When used by itself, polyethylene imine (PEI) does not perform well as cement fluid loss additive. Its combination with acetone formaldehyde sulfite (AFS) polycondensate, however, exhibits excellent filtration control. The mechanism underlying this synergistic effect was studied and the conditions producing best results were determined. For optimum performance, PEI and AFS must be reacted with each other to yield a polyelectrolyte complex (PEC) (d ~ 5–10 μm), which effectively plugs the pores of the cement filter cake. Composition, size, and effectiveness of the PEC are strongly influenced by the anionic charge amount of the AFS dispersant. Ionic interactions between cationic imine functionalities of PEI and anionic sulfonate groups existing in AFS were confirmed by conductivity, infrared, zeta potential, and particle size measurements. For AFS samples possessing different degrees of sulfonation, the largest particle size and hence best fluid loss performance of the PEC was found to occur at a PEI:AFS molar ratio, which corresponds to neutral charge. Occurrence of large PEC particles (d ~ 5 μm) within the cement filter cake pores was visualized by scanning electron microscopy, and their stability in highly alkaline cement pore solution was confirmed by particle size measurement. Other anionic polyelectrolytes may be used to yield such PECs with PEI to provide effective fluid loss control for cement slurries. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
34.
以醋酸纤维素(CDA)、异佛尔酮二异氰酸酯(IPDI)、聚醚2000(PPG2000)为主要原料,二月桂酸二丁基锡(DBTDL)为催化剂,二羟甲基丙酸(DMPA)为亲水扩链剂制备了一系列CDA改性的水性聚氨酯(WPU)。研究了CDA的乙酰基含量及CDA用量对乳液的粒径、黏度及对胶膜的力学性能、耐磨性、硬度的影响。利用红外光谱(FT-IR)及热重分析(TG)研究了胶膜的性能。结果表明:当CDA的乙酰基含量为43.5%,CDA的用量为6.8%,DMPA的用量为6.67%时,改性后胶膜的综合性能比较好。FT-IR表明,CDA成功接枝到PU分子骨架上;TG结果表明,CDA改性PU后,胶膜的热稳定得到明显提高。 相似文献
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利用PG(含少量甲基丙烯酸缩水甘油酯的苯乙烯-甲基丙烯酸甲酯无规共聚物)刷对ITO基板改性,在其上面旋涂不同厚度的聚苯乙烯-聚甲基丙烯酸甲酯嵌段共聚物(PS-b-PMMA)薄膜,对薄膜进行热退火和丙酮蒸汽退火处理,使用TEM、SEM、AFM对退火后的嵌段共聚物薄膜形貌进行表征。结果表明,热退火只能使最大厚度(120nm)约为3个相结构周期的薄膜相畴垂直取向,而后继续丙酮蒸汽退火30min,则能使厚度达4个相结构周期的薄膜相畴垂直取向。 相似文献
36.
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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利用DEAE—Sephadex分离柱及GC—MS对构树皮丙酮抽出物 进行了分离和分析.在丙酮抽出物中中性组分占抽出物的59.7%,弱酸性 组分和强酸性组分分别占25.9%和10.3%.中性组分中不皂化物占 89.2%,皂化物仅占8.4%.不皂化物的成分比较复杂,所检出的主要有 甾醇和甾酮类.皂化物中亚油酸占50%,软脂酸占21%.弱酸性组分中 50%以上是脂肪酸(亚油酸和软脂酸),而没有松香酸. 相似文献
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利用先共沉淀后水热处理的方法制备出水滑石前体,将其焙烧后,得到具有不同Mg/Al摩尔比的复合氧化物,并借助电感耦合等离子原子发射光谱、XRD、CO2-TPD和氮气吸脱附等手段对其进行表征。结果表明,Mg/Al摩尔比对催化剂的结构和碱性质有较大的影响,并且在催化丙酮和碳酸二甲酯合成乙酰乙酸甲酯的反应中,其比单纯的氧化镁和氧化铝表现出了更高的催化活性。进一步的研究表明,在该反应中是复合氧化物的中强碱性位起催化活性的作用,当Mg/Al摩尔比为2时,催化剂具有最高的活性。此外,重复性实验表明,这些催化剂具有较好的稳定性和重复使用性。 相似文献