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本文提出了一种合成永固紫RL的新方法,该方法以煤焦油副产物咔唑为起始原料,利用固-波相转移催化反应合成了N-乙基咔唑,混酸硝化工艺合成了纯度高达94.8%的3-硝基-9-乙基咔唑,再经还原反应、缩合反应、环化反应合成了永固紫RL。合威工艺新颖,总反应时间短,产品消耗低,收率高,是一个有工业化价值的合成方法。 相似文献
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本文对超临界CO2的特性及其在有机合成中的应用进行了综述,特别强调了它在加氢反应、羰基化反应、异构化反应、氧化反应、环化反应等中的具体应用和重要价值。 相似文献
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用Aspen Plus对反应精馏的模拟计算 总被引:3,自引:0,他引:3
以甲醇和醋酸的酯化反应为例,介绍了用Aspen Plus软件模拟计算反应精馏过程的方法。计算过程包括:(1)对反应精馏塔模型进行合理的简化;(2)选取合适的数学模型和热力学模型;(3)选取合适的参数。计算初步确定了最佳回流比,合理的甲醇过量程度,并通过灵敏度分析得出灵敏板的大概位置。本计算结果可作为反应精馏实验的基础。 相似文献
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芳基取代香豆素合成方法的研究进展 总被引:5,自引:2,他引:5
本文综述了在香豆素母体环上具有不同取代基的3-位和4-位芳基取代化合物的合成进展。其中Perkin反应以水杨醛和芳基乙酸为原料,在有机碱和醋酸酐存在下反应,而对于有N,N-二乙氨基取代的香豆素则需要用Knoevenagal反应在催化量的有机碱存在下由N,N-二乙氨基取代的水杨醛与芳基乙腈反应制得。由于一些取代水杨醛的合成比较困难,这时可利用Pechmann反应在路易斯酸催化下由取代酚直接反应制备香豆素化合物,以上这三种制备芳基取代香豆素的方法一般收率都较高,可应用于工业化生产,另外,在Vilsmeier-Haack反应中可用Vilsmeier试剂来制备芳基香豆素化合物。该反应副产物反物很少,条件比较温和,利用钯金属等催化合成的4-芳基香豆素化合物反应中,避免了常用的Pechmann反应中使用等当量的矿物酸或路易斯酸。可减少对环境带来的污染。 相似文献
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深入讨论了物理化学教学中的热化学部分中经常采用的反应进度和摩尔反应等重要概念,并采用摩尔反应概念时存在的一些问题和解决这些问题的方法。提出引用一种新的概念—单位反应概念,详细介绍单位反应概念并把它代替摩尔反应概念的优点。 相似文献
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Surface alteration of typical aggregates with alkali-silica reactivity and alkali-carbonate reactivity, i.e. Spratt limestone (SL) and Pittsburg dolomitic limestone (PL), were studied by XRD and SEM/EDS after autoclaving in KOH, NaOH and LiOH solutions at 150 °C for 150 h. The results indicate that: (1) NaOH shows the strongest attack on both ASR and ACR aggregates, the weakest attack is with LiOH. For both aggregates autoclaved in different alkali media, the crystalline degree, morphology and distribution of products are quite different. More crystalline products are formed on rock surfaces in KOH than that in NaOH solution, while almost no amorphous product is formed in LiOH solution; (2) in addition to dedolomitization of PL in KOH, NaOH and LiOH solutions, cryptocrystalline quartz in PL involves in reaction with alkaline solution and forms typical alkali-silica product in NaOH and KOH solutions, but forms lithium silicate (Li2SiO3) in LiOH solution; (3) in addition to massive alkali-silica product formed in SL autoclaved in different alkaline solutions, a small amount of dolomite existing in SL may simultaneously dedolomitize and possibly contribute to expansion; (4) it is promising to use the duplex effect of LiOH on ASR and ACR to distinguish the alkali-silica reactivity and alkali-carbonate reactivity of aggregate when both ASR and ACR might coexist. 相似文献
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Yujiro Hayashi Takahiko Itoh Hayato Ishikawa 《Advanced Synthesis \u0026amp; Catalysis》2013,355(18):3661-3669
A one‐pot transformation of aldehydes into α,β‐unsaturated aldehydes was developed using both N‐benzyl‐N‐methylamine and 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) as catalysts and MnO2 as a terminal oxidant. An oxidative and enantioselective reaction of aldehydes and nitromethane was established using both diphenylprolinol silyl ether and DDQ as a catalyst with MnO2 as a terminal oxidant, in which synthetically important β‐substituted γ‐nitro aldehydes were obtained with excellent enantioselectivity.
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In this study, chemical modification reactions of polystyrenes with different molecular weights with maleic and acetic anhydrides in the presence of a catalyst [BF3 · O(C2H5)2] were examined. The number of polyfunctional groups bound to the polymer structure changed according to the molecular weight of the polymer, and more functional groups were bound to lower molecular weight polystyrenes. The bound functional groups and their amounts were determined with spectral and chemical analysis methods. The effects of the molecular weights of the polystyrenes on the chemical modification kinetics with maleic and acetic anhydrides in the presence of BF3 · O(C2H5)2 were examined. The kinetic parameters of the reaction and its activation energy were calculated. The higher the molecular weight of polystyrene was, the lower its rate of modification was and the greater its activation energy was; the lower the molecular weight of polystyrene was, the higher its rate of modification was and the lower its activation energy was. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 253–259, 2005 相似文献