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31.
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Robert F. Smith Harold D. Pierce Jr. John H. Borden 《Journal of chemical ecology》1991,17(7):1437-1447
The first known sex pheromone for the family Miridae is reported for the mullein bug,Campylomma verbasci (Meyer) (Heteroptera: Miridae). Extracts of and Porapak Q-trapped volatiles from females were attractive to males in field bioassays. Butyl butyrate and hexyl butyrate were the predominant compounds in the females' volatiles, but these compounds previously had been found to be inactive when released alone or in combination. Butyl butyrate in combination with an isolated trace chemical, (E)-crotyl butyrate (which was inactive alone), rivaled the attraction elicited by five live females. When synthetic butyl butyrate and (E)-crotyl butyrate in a 16: 1 ratio were released at 91 or 183 g/day, they comprised an effective attractant for male bugs. 相似文献
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Lisa N. Yee Casimir C. Akoh Robert S. Phillips 《Journal of the American Oil Chemists' Society》1997,74(3):255-260
Pseudomonas sp. lipase PS was immobilized by adsorption and tested for its ability to catalyze the synthesis of citronellyl butyrate
and geranyl caproate by transesterification in n-hexane. The reaction parameters investigated were: enzyme load, effect of substrate concentration, added water, temperature,
time course, organic solvent, pH memory, and enzyme reuse. Yields as high as 96 and 99% were obtained for citronellyl butyrate
and geranyl caproate, respectively, with 300 units (approx. 15% w/w of reactants) of lipase PS. Increasing amounts of terpene
alcohol inhibited lipase activity, while excess acyl donor (triacylglycerol) concentration enhanced ester production. Optimal
yields were obtained at temperatures from 30–50°C after 24-h incubation time. Yields of 90 and 99% were obtained for citronellyl
and geranyl esters, respectively, with 2% added water. Solvents with log P values ≥ 2.5 showed the highest conversion yields. pH 7 and 6–8 seemed to be ideal for citronellyl butyrate and geraniol
caproate, respectively. The lipase remained active after reusing 12 times. 相似文献
35.
Blends of poly(3‐hydroxy butyrate‐co‐3‐hydroxy valerate) (PHBV) and poly(ethylene oxide) (PEO) were prepared by casting from chloroform solutions. Crystallization kinetics and melting behavior of blends have been studied by differential scanning calorimetry and optical polarizing microscopy. Experimental results reveal that the constituents are miscible in the amorphous state. They form separated crystal structures in the solid state. Crystallization behavior of the blends was studied under isothermal and nonisothermal conditions. Owing to the large difference in melting temperatures, the constituents crystallize consecutively in blends; however, the process is affected by the respective second component. PHBV crystallizes from the amorphous mixture of the constituents, at temperatures where the PEO remains in the molten state. PEO, on the other hand, is surrounded during its crystallization process by crystalline PHBV regions. The degree of crystallinity in the blends stays constant for PHBV and decreases slightly for PEO, with ascending PHBV content. The rate of crystallization of PHBV decreases in blends as compared to the neat polymer. The opposite behavior is observed for PEO. Nonisothermal crystallization is discussed in terms of a quasi‐isothermal approach. Qualitatively, the results show the same tendencies as under isothermal conditions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2776–2783, 2006 相似文献
36.
采用丁基橡胶研制用于中空玻璃单道密封的热熔胶.研究主体树脂品种、增黏剂、改性剂、填料的类型及用量对材料性能的影响.实验采用正交方法对胶料成分进行配比,在开放式塑炼机的混炼下得到热熔密封胶胶料,并测得胶料与玻璃的黏接性、拉伸性及流变性.实验结果表明:加入具有良好增黏作用的低分子聚异丁烯以及石蜡,都有利于提高胶条的黏接性能,丁基橡胶对胶条的拉伸性能影响最大,加入少量石蜡,可以降低黏度,增加其流动性. 相似文献
37.
38.
对再生丁基橡胶(RIIR)与非极性不饱和橡胶共混物的性能进行了研究。结果表明,RIIR易以填料的形式加入到非极性不饱和橡胶中使用,当RIIR以填料的形式加入到NR、BR及SBR中时,不仅使它们的耐热氧老化性及耐屈挠龟裂性得到明显改善,而且使NR及BR的撕裂强度及扯断伸长率提高;RIIR作为生胶与BR及NR共混,可改善BR的耐热氧老化性,提高NR的撕裂强度;SBR与RIIR共混,均使拉伸强度及撕裂强度降低;非极性不饱和二烯类橡胶与RIIR共混后,均使耐磨性降低。 相似文献
39.
Novel polymer blends were prepared from a mixture of 2 wt % konjac glucomannan and 4 wt % quaternized poly(4‐vinyl‐N‐butyl) pyridine (QPVP) in aqueous solution and dried at room temperature for 72 h. Their structure and properties were studied by infrared, wide‐angle X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry. Thermal stability in the dry state was reduced with increasing content of QPVP. Compared with QPVP film, the tensile strength of the films was improved in the dry state. The maximum value of 12.74% tensile break elongation was reached when the content of QPVP was 30%. Structural analysis indicated that clear phase separation was observed when the content of QPVP was only 50%. Results from the filmcoating preservation experiments with lychee showed that this blend film had water‐holding ability. The fruit weight loss rate and rot rate both decreased in various degrees. The potential uses of these novel polymer films could be as preservative films. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1868–1875, 2004 相似文献
40.
刘长令 《精细与专用化学品》2006,14(1):6-8
噁唑烷酮类化合物的活性中心是噁唑烷酮母环,文献报道的合成方法大多是以芳香胺类化合物为基本原料,以环氧丙烷衍生物为环合剂。作者采用苄氧羰酰芳胺和(R)-丁酸缩水甘油酯直接环合路线,并以间氟苯胺为原料,合成了(R)-[3-(3-氟-4-乙酰基苯基)-2-氧代-5-噁唑烷基]甲醇。 相似文献