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A novel environmentally benign process for the synthesis of methyl N-phenyl carbamate (MPC) from methanol and phenylurea was studied. Effect of solvent and catalyst on the reaction behavior was investigated. The IR spectra of methanol and phenylurea dissolved in different solvents were also recorded. Compared with use of methanol as both a reactant and a solvent, phenylurea conversion and selectivity to MPC increased by using toluene, benzene or anisole as a solvent, while phenylurea conversion decreased slightly by using n-octane as a solvent. The phenylurea conversion declined nearly 50% when dimethyl sulfoxide (DMSO) was used as a reaction media, and MPC selectivity decreased as well. The catalytic reaction tests showed that a basic catalyst enhanced the selectivity to MPC while an acidic catalyst promoted the formation of methyl carbamate and aniline. Moderate degree of basicity showed the best catalytic performance in the cases studied. 相似文献
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LIU Zhao-Tie ZHOU Jing-LaiZHANG Zhi-Xin ZHANG Bi-Jianginstitute of Cual Chemistry Academia Sinica Taiyuan Shanxi To whom correspondence should be addressed. 《天然气化学杂志》1995,(1)
The influence of reaction pressure, temperature, space velocity (GHSV), particle size of catalyst and H2/CO ratio of feed-gas on the steady-state product distribution, conversion of CO, H2 and syngas, olefin to paraffin ratio and CO2/ H2O ratio for FTS reaction were investigated using a coprecipitated copper- potassium promoted iron catalyst. The test was carried out in a fixed-bed reactor. Increasing the reaction temperature from 493. 2 to 5-13. 2 K shifted the hydrocarbon distribution toward the heavier hydrocarbons (C5-C23) and selectively increased CO conversion to CO2. The hydrocarbon distribution was found to be dependent on the H2/CO feed-gas ratio in the range from 1.23 to 2. 22. The CO2/H2O ratio in product decreased as the flow of feed-gas rate increased, which suggests that H2O is a primary product and its reaction with CO to form CO2 occurs via a secondary process. The CO conversion increased with the decrease of catalyst particle size from 10 to 60 mesh (2. 0- 0. 3 mm), while the CO convers 相似文献
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本文提出了测定焙烤食品中聚甘油酯添加剂的气相色谱法。它是基于氯仿抽提、皂化、分离亲水基,然后经三甲基硅烷化,内标法测定亲水基含量,并经定量校正曲线换算得聚甘油脂肪酸酯的含量。 相似文献
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ZhengBaoZHAO JingGUO YuanGuiWEI TongDaLIANG 《中国化学快报》2005,16(7):889-892
To search for a better prodrug of 4-aminosalicylic acid that is expected to deliver stably parent drug to colon against the inflammatory bowel disease, a novel 4-aminosalicylic acid derivative was designed and synthesized from 4-aminosalicylic acid. 4-Aminosalicylglycine was prepared from 4-aminosalicylic acid by protecting amino and hydroxyl groups with benzyloxycarbonyl and acetyl, respectively, then the carboxylic acid was converted to acyl chloride which was treated with glycine. After removing the protection groups, 4-aminosalicylglycine wasobtained. All the compounds were characterized by FT-IR, ^1H-NMR, ^13C-NMR spectra. In vivo experiment on rats suggested that the curative effect of 4-aminosalicylglycine was more effective than that of 4-aminosalicylic acid. 相似文献
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Pin YANG* Yan Fang SHANG Zhen Ming PEI Institute of Molecular Science Shanxi University Taiyuan Department of Biology Duke University Durham NC 《中国化学快报》2001,(9)
Rare earth fertilizers were applied widely in China. They were employed by 3.3(106 hm2 every year and the production of crops increased up to 109 kg. The economic benefit is huge, but the action mechanism of these fertilizers is not clear yet1. The distributions of rare earth elements in plant cell were still disputed. Because lanthanons in organism were in minute quantities (10-10~10-8 in mass percentage), it was necessary to choose a sensitive and exact analytical method.In recent years Pa… 相似文献
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AAS法对几种调味品中微量元素的测定 总被引:1,自引:0,他引:1
本文采用原子吸收法测定了六种调味品中Sr,Ba,Fe,AI,Cu,Cr,Zn,Mo,Ni,Co,Mn,Cd,Mg等十三种微量元素含量。结果表明,不同的调味品中各微量元素含量均有较大差别。本实验同时对姜粉中各元素进行了回收实验,回收率在90%-108%之间。 相似文献
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贵金属元素分离富集技术进展 总被引:1,自引:0,他引:1
本文介绍了近10年来国内外贵金属分析中的分离富集技术进展情况。并分别对火试金分离法、共沉淀法、溶剂萃取法、离子交换法、萃淋树脂法、液膜分离法、吸附剂法等多种分离富集技术进行了评述。最后对未来贵金属元素分离富集技术发展趋势进行了展望 相似文献