共查询到20条相似文献,搜索用时 203 毫秒
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生物质基平台化合物糠醛和5-羟甲基糠醛来源广泛,可从绿色植物中提取得到.糠醛和5-羟甲基糠醛双键加氢制备四氢糠醇和2,5-二羟甲基四氢呋喃具有重要的研究价值.文章综述了近年来糠醛和5-羟甲基糠醛双键加氢反应的研究成果,重点阐述了反应机理的研究进展,讨论了不同催化体系(单金属、合金)对糠醛和5-羟甲基糠醛双键加氢的催化作... 相似文献
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通过生物质衍生糖的酸催化转化制备生物质基平台化合物5-羟甲基糠醛受到关注。常用又有效的溶剂包括离子液体和二甲基亚砜等,但这些溶剂黏度高,易造成空气污染。以γ-戊内酯作为溶剂,研究果糖催化转化为5-羟甲基糠醛的绿色过程,系统研究酸催化剂种类、反应温度、催化剂用量、果糖初始浓度及底物种类等对5-羟甲基糠醛产率的影响。通过反应条件的优化,以HCl溶液为催化剂,在果糖初始质量浓度2%、反应温度100℃和反应时间30 min条件下,5-羟甲基糠醛产率为93.5%。5-羟甲基糠醛产率随果糖初始添加量的增加而呈下降趋势,但果糖初始质量浓度为10%时,5-羟甲基糠醛产率仍保持约90%,表明γ-戊内酯是一种将果糖催化转化为5-羟甲基糠醛的优良绿色溶剂。 相似文献
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D. G. Gordeev L. F. Gudarenko M. V. Zhernokletov V. G. Kudel’kin M. A. Mochalov 《Combustion, Explosion, and Shock Waves》2008,44(2):177-189
A semi-empirical equation of state for metals is described. Its capabilities are demonstrated by the example of the equation
of state for aluminum. New experimental data are presented on the location of the isentrope of aluminum for unloading from
the state at p = 229.71 GPa on the shock adiabat to an aerogel (SiO2) of density 0.08 g/cm3.
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Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 2, pp. 61–75, March–April, 2008. 相似文献
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Jorge Marcelo Romero Soledad Bustillo Hugo Enrique Ramirez Maisuls Nelly Lidia Jorge Manuel Eduardo Gómez Vara Eduardo Alberto Castro Alicia H. Jubert 《International journal of molecular sciences》2007,8(7):688-694
A thermochemical rather simple experimental technique is applied to determine the enthalpy of formation of Diperoxide of ciclohexanone. The study is complemented with suitable theoretical calculations at the semiempirical and ab initio levels. A particular satisfactory agreement between both ways is found for the ab initio calculation at the 6–311G basis This set level. Some possible extensions of the present procedure are pointed out. 相似文献
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醋酸纤维素取代基分布与性质的关系 总被引:9,自引:0,他引:9
分析了以吡啶为溶剂的醋酸纤维素的13C-NMR核磁共振谱,得出了三种不同位置羟基的取代度。结合X—射线和DSC分析,初步说明具有相同取代度但未经水解和经过水解的醋酸纤维素(CA) 性质上的差异是由于三个羟基上的取代度分布不同及消晶程度差异所致。 相似文献
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乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。 相似文献
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介绍了平板硫化机热板中高度在硫化排气过程中的作用及其实现途径和评价方法;提出了设置热板中高度时应遵守的"刚性横梁、柔性热板"概念和"最短路径、最小排气阻力"原则;探讨了横梁热变形对热板中高度的影响。结果表明,参考横梁热变形设置的热板中高度有助于解决平板硫化机在复杂状态下硫化制品时的表面排气问题。 相似文献
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A Review of Contemporary Views of Theories of Adhesion 总被引:2,自引:0,他引:2
K. W. Allen 《The Journal of Adhesion》1987,21(3):261-277
The once distinct and independent theories of adhesion have been losing their isolation and converging. Ideas of the effects of surface roughness, once dismissed as irrelevant except in the case of textiles, have been revised; albeit on a smaller scale as details of surfaces have been revealed by sophisticated techniques. Electrostatic interactions across an interface have been more deeply explored and their significance recognised and expounded. Diffusion of groupings and chain segments within a polymer have been related to the possibilities of interaction with a variety of surfaces. Perhaps most important, theories of adsorption have been extended in depth. The precise nature of the molecular interactions have been recognised and quantified. In doing this the contribution of diffusion and elastoplastic phenomena have been integrated. These developments are collated and analysed to present the present understanding of the concepts. 相似文献