共查询到19条相似文献,搜索用时 156 毫秒
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对消旋正丁基苯酞的化学拆分方法进行了改进,提高了终产物的光学纯度和总收率。方法如下:先将消旋正丁基苯酞在氢氧化钠水溶液中开环、酸化,再与拆分试剂——左旋α-苯乙胺反应得到2个非对映异构体胺盐的混合物,然后用丙酮和左旋α-苯乙胺的混合溶液重结晶,得到左旋正丁基苯酞的左旋α-苯乙胺盐,酸性条件下将其解离并环合,减压蒸馏得到左旋正丁基苯酞,并通过对比实验确定了最优化的工艺条件。改进后的拆分方法有效抑制了左旋正丁基苯酞的左旋α-苯乙胺盐在重结晶过程中的热分解,提高了产物左旋正丁基苯酞的光学纯度(99%ee)和总收率(25%)。 相似文献
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<正> 一、概述众所周知,酞酰化PA改性胶是苯二甲酸酐与明胶的氨基发生酞酰化作用,以及与明胶的羟基发生酯化作用而使明胶改性的产物。当然,酞酚化是其中主要作用。随着改性反应时酞酐加入量的不同和反应条件控制上的差别,以及采用改性胶与非改性胶混合的办法,会使改性胶的结合酞酐值在颇大范围内变化而形成系列。根据收集到的国内外PA改性胶样品,经测定以结合酞酐值表征改性度,最低为0.14毫克分子数/克(或2.1%),最高为0.48毫克分子数/克(或 相似文献
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介绍了以邻苯二甲酸二正辛酯为内标物,用RXI–17毛细管柱、FID检测器,对四氯苯酞原药进行气相色谱分离和定性、定量分析。采用该方法分析四氯苯酞的线性相关系数为0.9998,变异系数为0.17%,平均回收率为99.7%。该方法操作简便,适用于产品的常规分析和质量控制。 相似文献
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邻苯二甲酸酐与 Zn/ HCl作用 ,一步合成邻羟甲基苯甲酸内酯 ,操作简便 ,反应条件温和 ,原料价廉易得 ,收率 81 .7%。 相似文献
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BACKGROUND: Pseudodendrimers are hyperbranched polymers which are isomeric with dendrimers, that is, each repeat unit is either fully reacted or only singly reacted. The careful design of an ABB′ monomer leads to higher branching by virtue of tandem reactions that increase the reactivity of linear units during polymerization, leading to fully reacted repeat units. The resulting polymers are predicted to be very highly branched, and in the optimum case, pseudodendrimers. RESULTS: Our work shows that 6‐amino‐3‐bromophthalide leads to a highly branched polymer via bromohydrin decomposition during polymerization, giving polymers of M? = of 3000 and a polydispersity index of 1.03. Our findings indicate a degree of branching of 0.84. The synthesis of similar polymers using different techniques confirms our proposed intermediate. CONCLUSION: We have demonstrated a new class of hyperbranched polymers which are highly branched, and may be considered pseudodendrimers. Copyright © 2009 Society of Chemical Industry 相似文献
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A series of organic‐soluble polynaphthalimides (PNI) bearing flexible ether links and phthalide cardo group were synthesized from 1,4,5,8‐naphthalenetetracarboxylic dianhydride (NTDA) with 3,3‐bis[4‐(4‐aminophenoxy)‐3‐methylphenyl]phthalide (BAMP) and its equimolar mixtures with other dietheramines by high‐temperature solution polycondensation in m‐cresol. The PNIs had moderate to high inherent viscosities in the range of 1.24–2.25 dL/g and could afford flexible and tough films with tensile strengths of 97–138 MPa by casting their m‐cresol solutions. These PNIs exhibited high thermal stability, with glass transition temperature of 291°C–321°C, 10% weight‐loss temperatures above 542°C, and char yields at 800°C in nitrogen higher than 56%. In comparison with PNIs without the BAMP component, these BAMP‐modified PNIs revealed an enhanced solubility and film‐forming capability. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1104–1109, 2007 相似文献
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以NaBH4对疏水活性炭进行处理,采用等体积浸渍法制备疏水活性炭负载掺杂助剂Fe的Ni基催化剂,用于苯酐液相选择性加氢制苯酞,考察Ni含量和活性炭处理对催化剂性能的影响。结果表明,疏水活性炭经NaBH4处理后制备的15%Ni-Fe/C催化剂对苯酐加氢表现出很好的催化性能,在180 ℃、4.0 MPa、苯酐5.0 g、催化剂用量以Ni占原料质量的1%计和甲苯50 mL条件下,苯酐转化率为100%,苯酞选择性为95.2%,催化剂重复使用5次,仍保持很好的活性和选择性。 相似文献
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Preparation and properties of aromatic-aliphatic cardopolyamides from phenoxathiins and thianthrenes
Several new aromatic-aliphatic cardopolyamides containing phenoxathiin and thianthrene derivatives were prepared by the direct polycondensation of 2,8-phenoxathiin-bis(γ-ketobutyric acid) (PA) or 2,7-thianthrene-bis(γ-ketobutyric acid) (TA) with 3,3-bis(4-aminophenyl phthalide) (PDA), 9,9-bis(4-aminophenyl fluorene (FDA), or 9,9-bis(4-aminophenyl) anthrone (ADA) in a triphenyl phosphite-pyridine system. The cardopolyamides were obtained in 80–95% yield and possessed viscosities in the range 0.90-1.35 dl/g. They showed better solubility and heat resistance than analogous noncardopolyamides derived from conventional diamines. All the polymers were characterised by IR spectra, density, solubility, crystallinity and thermal analysis. Integral procedural decomposition temperatures (IPDT) were calculated from the primary thermograms in the temperature range 100–650°C to give quantitative data regarding the thermal stabilities. The molecular weight and molecular weight distribution of the polyamides were determined by gel-permeation chromatography (GPC). 相似文献