共查询到20条相似文献，搜索用时 46 毫秒
1.
阿司匹林的合成条件研究 总被引：7，自引：0，他引：7
以水杨酸和醋酐为原料经O-酰化反应合成阿司匹林，比较了三氯化铝、三氯化铋和无水碳酸钠三种不同催化剂以及反应条件对合成的影响，找到了最佳催化剂和最佳反应务件，即以三氯化铝为催化剂，其用量为水杨酸的2％，水杨酸与醋酐的摩尔比为1：2，反应时间为30min，回流温度为85℃左右，阿司匹林产率可迭72．6％。实验表明该催化剂催化效果好．不污染环境，是一种环境友好的催化剂。同时，本法简单、快速、经济、无污染，产品质量好，适于工业化生产。 相似文献
2.
杂多酸催化合成醋酸丁酯的研究 总被引：2，自引：1，他引：2
本文研究了以磷钼杂多酸为催化剂，以无水氯化钙为吸水剂催化合成醋酸丁酯，并探讨了酸反应条件。结果表明，磷钼杂多酸具有较高的催化活性和选择性，在最佳条件下，酯产率可达９６％，产品质量符合国标要求，该方法操作简便，条件容易控制，无污染。 相似文献
3.
对甲苯磺酸催化合成乙酸异戊酯的研究 总被引：8，自引：0，他引：8
研究了以对甲苯磺酸为催化剂、以无水氯化钙为吸水剂,催化合成乙酸异戊酯的新方法,探讨了酯化反应的条件。结果表明,对甲苯磺酸具有较高的催化活性,在最佳条件下,酯产率可达９４％以上,产品质量符合要求。本方法操作简便、反应时间短、反应条件易控制、无污染。 相似文献
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研究了以复合型固体超强酸为催化剂率合成醋酸正丁酯,探讨了酯化反应条件和催化剂的制作工艺对酯产生率的影响,实验结果表明,复合型固体超强酸（ＳＯ＾２－４／ＺｒＯ２－Ａｌ２Ｏ３）具有较高的催化活性和选择性,在最佳工艺条件下醌产率可达９６％,产品质量符合国标要求,该工艺操作简便,条件易控制,对环境无污染。 相似文献
5.
杂多酸(盐)催化合成水杨酸正丁酯的研究 总被引：3，自引：0，他引：3
比较了多种杂多酸及其盐催化合成水杨酸正丁酯的反应，找到了该反应的最佳催化剂，并用正交试验法得出了反应的最优化条件，即醇酸摩尔比为2：1，催化剂用量为改质量的7％，反应时间为4h，酯产率可达87．7％。实验表明该催化剂催化活性高，选择性好，对设备无腐蚀，是一种环境友好的催化剂。 相似文献
6.
以对氯苯甲醛和丙酮为原料，以PSTEA作相转移催化荆合成对氯苄又丙酮。对氯苄又丙酮经磺化反应合成了苄又丙酮磺酸钠。讨论了影响缩合反应与磺化反应的主要因素，得到了最佳反应条件。合成对氯苄又丙酮的最佳工艺条件：以0．4gPSTEA为催化荆，15ml 5％的NaOH为反应介质，0．1mol对氯苯甲醛与20ml丙酮缩合，对氯苄又丙酮的收率达97％；合成苄又丙酮磺酸钠的最佳工艺条件：以0．002mol氧化镁为催化荆，0．1mol对氯苄又丙酮与0．13mol亚硫酸钠在150℃反应3h，对氯苄叉丙酮的收转化率为82％。 相似文献
7.
大孔树脂催化合成增塑剂DBP的研究 总被引：3，自引：0，他引：3
杨志成 《华东地质学院学报》1998,21(2):171-177
本文论述了以功能树脂ＤＯＯＸ为催化剂,邻苯二甲酸酐和正丁醇为原料合成邻苯二甲酸二丁酯的新方法。实验表明,该催化剂具有活性高、选择性好、工艺流程简单、催化剂易回收并可重复使用等优点。在最佳工艺条件下,酯产率可达９０％以上。本方法无环境污染,易于工业化生产。 相似文献
8.
离子交换树脂催化合成丙烯酸正丁酯 总被引：2，自引：0，他引：2
论述了以丙烯酸、正丁醇为原料,离子交换树脂作催化剂,催化合成丙烯酸正丁酯的新工艺。考察了催化剂种类、用量、原料配比、反应时间、阻聚剂用量以及催化剂使用次数等因素对酯化率的影响,确定了催化剂种类和最佳工艺条件。结果表明,７３１强酸性离子交换树脂具有良好的催化活性和选择性,可多次重复使用,酯化率可达８２．０％,产品质量符合国家标准,该工艺操作简单,条件容易控制,对环境无污染。 相似文献
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10.
药物中间体2-乙基苯并咪唑的合成 总被引：7，自引：0，他引：7
报道了以邻苯二胺和丙酸为原料,磷酸催化合成药物中间体２－乙基苯并咪唑的研究。对反应条件进行了试验,结果表明,最佳的反应条件为：邻苯二胺与丙酸的摩尔比为１∶２．５,反应时间为２．０ｈ,反应温度约为１００℃,催化剂磷酸的用量为１．５ｍＬ,析出的游离２－乙基苯并咪唑的ｐＨ为９～１０。合成的转化率高达７８．０９％。 相似文献
11.
Emily Keeble David I. Whiteside Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119
Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco. 相似文献
12.
Gilles Serge Odin 《Comptes Rendus Geoscience》2002,334(6):409-414
Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414. 相似文献
13.
The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts 总被引：4，自引：0，他引：4
The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H2O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H2O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species. 相似文献
14.
Muriel Rocher Stéphane Baize Stéphane Jaillet Edward Marc Cushing Yannick Lozac&#x;h Francis Lemeille 《Comptes Rendus Geoscience》2003,335(8):701-708
Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ1 roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003). 相似文献
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正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level 相似文献
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正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7), 相似文献
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正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci- 相似文献
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正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli- 相似文献
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正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.) 相似文献