共查询到19条相似文献,搜索用时 156 毫秒
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制备了一种以苯并噻唑为阳离子和硫酸氢根为阴离子的新型磺酸官能化酸性离子液体[(CH2)3SO3HBth][HSO4],并用于催化环己酮与乙二醇的缩酮化反应。通过考察原料配比、反应时间、催化剂用量、带水剂用量和催化剂重复使用次数等因素对反应的影响,确定1,4-二氧螺环[4,5]癸烷合成工艺最佳条件为:环已酮用量0.01 mol,乙二醇用量0.02 mol,催化剂用量为环已酮物质的量的5%,带水剂环已烷用量10 mL,回流反应时间3 h。在此条件下,1,4-二氧螺环[4,5]癸烷收率97.30%,催化剂具有良好的稳定性,循环使用5次后,催化活性没有明显下降。 相似文献
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以酸活化的活性二氧化硅为载体,采用化学键合的方法制备了3-氨丙基三乙氧基硅烷(APTES)化二氧化硅负载的Keggin型磷钨酸催化剂(HPW/APTES-SiO2),用红外光谱分析、X射线衍射、比表面积(BET)测定、热重-差热分析对催化剂进行了表征。将该催化剂用于合成环己酮甘油缩酮的反应,实验结果表明,2-羟甲基-1,4-二氧杂螺环[4,5]癸烷是主要产物,在优化反应条件下得到环己酮转化率为92.7%,主产物的选择性达97.8%,且催化剂便于从反应体系中分离,能重复使用4次。 相似文献
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以1,4,9,12-四氧杂二螺[4.2.4.2]十四烷为原料,采用酸性条件下水解缩酮选择性地脱除单侧羰基保护的方法合成了1,4-二氧杂螺[4.5]癸烷-8-酮.通过对盐酸、硫酸、甲酸、醋酸等催化性能的比较,对选择性的机理和影响因素进行了探讨,确定醋酸作为催化剂.优化了反应工艺条件,并对产品进行了IR、1HNMR的确认.结果表明,以冰醋酸作催化剂,反应溶剂V(冰醋酸):V(H2O)=5:1,反应浓度为0.05 g(mL(1,反应温度为65℃时,与原方法相比,反应时间由15 h缩短为约11 min, 产物的色谱收率由65%提高到80%. 相似文献
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以3-异丙氧基-4-甲氧基苯胺(2)和1,4-二氧螺[4.4]壬烷-6-羧酸(3)为原料,经过缩合反应得到N-(3-异丙氧基-4-甲氧基苯基)-1,4-二氧螺[4.4]壬烷-6-甲酰胺(4),然后经过酸性条件下脱乙二醇保护得到N-(3-异丙氧基-4-甲氧基苯基)-2-氧代环戊烷甲酰胺(1),产物结构经~1H NMR、~(13)C NMR和ESI-MS确证。并确定脱乙二醇反应条件为:反应温度25℃,反应时间30min,在该条件下产物收率72.6%。 相似文献
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具有手性的氧代螺环异吲哚啉衍生物可作为天然药物的活性结构单元,这些化合物在医药和化工领域具有重要的研究价值。实验以1,4-二氧螺环[4.5]癸烷-8-酮和苯甲酸酐为原料,经过一系列反应制得2-(1-(4-氧代双环[4.1.0]庚基-1-)丙基-2-)异吲哚啉-1,3-二酮,并利用高效液相色谱(HPLC)、液质联用仪(LCMS)、核磁(NMR)对其结构进行表征。 相似文献
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A general procedure for the determination of the first double bond position in the side-chain of a phenolic lipid has been
investigated and, in the first place, the phenols of natural cashew nut-shell liquid (Anacardium occidentale) have been examined. An improved oxidative degradation procedure has been applied consisting of methylation by the phase
transfer procedure, hydroxylation with performic acid and oxidation of the mixture of vicinal diols with periodic acid (Malaprade
reaction) followed by reduction of the aldehyde fragments with sodium borohydride. The aromatic moieties from the 15∶1, 15∶2
and 15∶3 constituents of cardanol methyl ether, cardol dimethyl ether and dimethyl anacardate were shown to be 8-(3-methoxyphenyl)octan-1-ol,
8-(3,5-dimethoxyphenyl)octan-1-ol and 6-(8-hydroxyocyl)salicylate methyl ether, respectively. The first two octanols were
identical to synthetic materials, thus confirming the 8-position for the first double bond in the side-chain of cardanol methyl
ether and cardol dimethyl ether constituents. Methyl 6-(8-hydroxyoctyl)salicylate relationship in a series of synthetic reference
materials of log (retention time) to the methylene chain length. The synthetic acids 8-(3-methoxyphenyl)octanoic acid, 8-(3,5-dimethoxyphenyl)octanoic
acid and 6-(7-carboxyheptyl)salicylic acid methyl ether have been obtained pure for the first time and correspond to the oxidation
products of the aromatic aldehyde fragments from the Malaprade reaction stage. The unsaturation in peladjauol, 17∶1-bishomocardanol
methyl ether, fromPentaspadon officinalis was confirmed to be at the 8-position by the identity of the anilides of synthetic 8-(3-methoxyphenyl) octanoic acid and
of the oxidative degradation product.
For part XIX, see ref. 1. 相似文献
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以4,5-二硝基邻苯二胺和2-羟基对苯二甲酸单甲酯为起始原料,设计并成功采用一锅法合成出2-羟 基-4-(5,6-二硝基-1H-苯并[2,3-d]咪唑-2-基)苯甲酸甲酯(MHDIB)。以50 mL二乙二醇二甲醚为溶剂,1.5 g的2-羟基对苯二甲酸单甲酯和2.5 g SOCl2在80 ℃反应2 h制2-羟基-4-氯羰基苯甲酸甲酯。室温下快速向反应体系中加入1.56 g 4,5-二硝基邻苯二胺,并于85 ℃反应1 h后加入3.52 g 多聚磷酸,回流反应1 h后水析出粗产品,经乙醇重结晶得到纯度为93.67%的黄色针状产物,产率为17.82%。产物经IR、MS、1H NMR的准确定性和表征,作为AB型新单体的前体可应用于羟基改性PBI纤维即聚2-羟基-1,4-亚苯基-2,6-苯并[2,3-d:5',6'-d']二咪唑(H-PBI)的创新研究。 相似文献
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Synthesis of cis‐1,4‐polyisoprene with Al‐Ti catalysts modified by different electron donor reagent
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The preparation of the high cis ?1,4‐polyisoprene by Ziegler‐Natta catalysis system was studied. The effect of Al‐Ti catalysts modified by ethers with different structures which are different electron donor reagent on polymerization of isoprene has been mainly investigated. By the measurement method of the monomer conversion, FTIR, and 1H NMR spectroscopy, the influence of, respectively, added diphenyl ether, anisole, dibutyl ether, or methyl tert ‐butyl methyl ether as a third active component on the heterogeneous TiCl4‐Al(i ‐Bu)3‐ether catalyst activity and microstructure of synthetic polyisoprene was analyzed. By the adding of diphenyl ether or dibutyl ether, the process of prefabricated heterogeneous catalyst is quickly and catalyst particle quantity is large. The polymerization conversion is high and the microstructure cis ?1,4 content of the resulting polymer can reach 92%. But Al(i ‐Bu)3 added anisole or methyl tert ‐butyl methyl ether hard to cooperate with TiCl4. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 44357. 相似文献
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The highly regioselective cobalt‐catalysed 1,4‐hydrovinylation of terminal alkenes with 2‐trimethylsilyloxy‐1,3‐butadiene generates in a stereospecific fashion unsaturated E‐configured silyl enol ether intermediates that are suitable for diastereoselective Mukaiyama‐aldol reactions with bulky aliphatic aldehydes. The acidic hydrolysis of the enol ethers to γ,δ‐unsaturated ketones followed by ozonolysis can be used for the synthesis of various 1,4‐diketones and polycarbonyl derivatives. The 1,4‐diketones and polycarbonyl derivatives were successfully tested for the synthesis of some mono‐ and bis‐pyrrole derivatives. The γ,δ‐unsaturated ketones are useful building blocks (e.g., in natural product synthesis) and can be generated in a one‐pot procedure. 相似文献
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