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常压下电化学催化羰化直接合成异氰酸酯 总被引:2,自引:0,他引:2
近 2 0多年来 ,异氰酸酯的非光气合成方法一直受到人们的关注 [1] .采用 CO与硝基化合物羰化直接合成相应的异氰酸酯在理论上完全可行 [2 ] ,但由于异氰酸酯本身在所采用的高温、高压反应条件下很不稳定 ,实际产率很低 ,CO在醇存在下与硝基化合物催化还原羰化 [3 ,4 ] ,或与有机胺在氧气存在下催化氧化羰化 [5,6] 生成相应的化学性质较稳定的氨基甲酸酯 ,再将氨基甲酸酯通过高温热裂解生成异氰酸酯[7,8] .该反应在高温、高压下进行 ,条件较苛刻 ,因此探索在较温和的条件下实现直接合成异氰酸酯的途径是目前该领域中很具有挑战性的研究课题… 相似文献
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Au(PPh3)2Cl,[Au(PPh3)]2S等有机金配合物催化羰化脂肪族二胺制相应二酰胺显示出非常好的活性,与同一类的有机钯催化剂相比,具有更好的催化转化能力和选择性。实验结果还表明适量分子氧的引入对反应有明显的促进作用。 相似文献
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扩链剂对脂肪族聚氨酯脲和聚脲弹性体结构与性能的影响 总被引:4,自引:0,他引:4
用异佛尔酮二胺(IPDA)、乙二胺(EDA)和己二胺(HDA)三种扩链剂合成了不同结构的脂肪族聚氨酯脲和聚脲, 并考察了扩链剂对聚氨酯脲和聚脲形态结构与性能的影响. 研究结果表明, 与EDA和HDA扩链的聚氨酯脲和聚脲相比, IPDA扩链的聚氨酯脲和聚脲中脲羰基的氢键化程度较低, 软段和硬段间的相混合程度较好; 同时它们具有更好的拉伸强度、硬度和撕裂强度, 但断裂伸长率较低. EDA和HDA扩链的聚氨酯脲和聚脲相比, 两者性能相差不大. 聚氨酯脲的脲羰基较完善氢键化程度以及整个氢键化程度都比聚脲的要低, 同时聚氨酯脲的吸水率也较低. 相似文献
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采用Pd(OAc)2/[mmim]I催化体系,在不同反应条件下可以将烷基胺、芳香胺及氨基醇(酚)一步转化为氨基甲酸酯、脲和2-噁唑啉酮.N-苯基氨基甲酸甲酯、二苯基脲及苯并-2-噁唑酮的催化转化频率分别为12417,17638和4114h-1. 相似文献
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3, 4-Bis (trifluoromethyl)-perfluorohexene-(3) (1) reacted with diethylamine to give the 1-N, N-diethylamino-2-pentafluoroethyl -3-trifluoromethyl-perfluoropentene-(1)(2), which was easily hydrolyzed to the corresponding N, N-diethyl-2-penta-fluoroethyl- 3-trifluoromethyl-perfluoropenteno-(2)-amide (3). When compound 1 was allowed to react with n-butyl amine at 40-50`C, the 2,3,4-tris(trifluoromethyl)-4-pentafluoroethyl-1-n-butyl-aza- cyclobutene-(2) (5) was obtained as the main product and at-30-40`C, 3,4-bis(trifluoromethyl)-4-n-butylamino-perfluorohexene-(2) (4) as the main product. The isomers 3, 4-bis(trifluoromethyl)-4-allyloxy-perfluoro-hexen-(2) (6) and 2-pentafluoroethyl-3-trifluoromethyl-3-allyloxy-perfluoropentene-(1)(7) were formed when 1 was reacted with sodium allyl alcoholate. 相似文献
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The rate constants kred of the thermal electron-transfer reaction between several aminoalkyl radicals and two ground-state aromatic ketones, benzophenone (BP) and thioxanthone (TX), were measured by nanosecond transient photoconductivity in acetonitrile. The kred values were strongly at variance from those expected from the free energy change Gred of the reaction within the framework of the Marcus' theory of electron transfer. Moreover, addition of small amounts of water in acetonitrile strongly enhanced kred and the ion quantum yield. These results were rationalized by invoking a 1 : 1 complex formation between amino-alkyl radicals and water, and semi-empirical AM1 calculations were used to sustain this explanation. 相似文献
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The palladium-catalyzed allene transformation reaction from propargylic amines proceeded in the presence of Pd2(dba)3·CHCl3 (5 mol %) and (C6F5)2PC2H4P(C6F5)2 (10 mol %) in CHCl3 at room temperature to give the corresponding allenes in good to high yields. Dicyclohexyl groups substituted on the nitrogen of propargylic amines were found to be effective for the current transformation and the conjugated ene-allenes 4 were synthesized from the corresponding propargylic amines 3 under mild conditions. 相似文献
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Treatment of amines under a carbon dioxide atmosphere with tetramethylphenylguanidine (PhTMG) and diphenylphosphoryl azide (DPPA) in acetonitrile below 0 degrees C provides carbamoyl azides in high to excellent yields. In addition, epimerization is not observed when optically pure alpha-amino esters are used as substrates. 相似文献
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Naoto Aoyagi 《合成通讯》2017,47(5):442-448
Cyclic guanidine hydroiodides were obtained in one step by the reactions of isothiouronium iodides with an equimolar amount of various amines in tetrahydrofuran. The obtained hydroiodides were neutralized with sodium hydroxide or anionic exchange resin to afford the corresponding substituted cyclic guanidines in quantitative yields. 相似文献
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Bismuth triflate catalyzes the ring opening of epoxides with aromatic amines under aqueous conditions. The reaction proceeds rapidly and affords the corresponding β-amino alcohols in excellent yields. 相似文献
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Balaraman E Gnanaprakasam B Shimon LJ Milstein D 《Journal of the American Chemical Society》2010,132(47):16756-16758
The selective, direct hydrogenation of amides to the corresponding alcohols and amines with cleavage of the C-N bond was discovered. The expected products of C-O cleavage are not formed (except as traces in the case of anilides). The reaction proceeds under mild pressure and neutral, homogeneous conditions using a dearomatized, bipyridyl-based PNN Ru(II) pincer complex as a catalyst. The postulated mechanism involves metal-ligand cooperation by aromatization-dearomatization of the heteroaromatic pincer core and does not involve hydrolytic cleavage of the amide. The simplicity, generality, and efficiency of this environmentally benign process make it attractive for the direct transformations of amides to alcohols and amines in good to excellent yields. 相似文献