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为建立混合物中羟基封端聚丁二烯(HTPB)的临界点色谱定量方法,以C18为固定相,考察了HTPB在四氢呋喃-乙腈和四氢呋喃-水两种流动相体系下的临界点色谱条件。结果表明,四氢呋喃-乙腈体积比为70.7:29.3以及四氢呋喃-水体积比为92:8时,HTPB的保留值与其相对分子质量无关。将该临界点色谱方法用于胶黏剂混合组分中HTPB的测定,结果表明,HTPB在46.7~216.4 mg/L范围内呈良好线性关系,相关系数(r)>0.99,检出限为4.2 mg/L。自配HTPB和矿物油双组分样品的加标回收率为89.2%~101.1%,相对标准偏差小于0.66%(n=6)。应用该方法对市售聚氨酯胶黏剂进行检测,测定结果为HTPB成分占26.6%。该方法快速、准确,能满足聚合物混合产品的生产质量控制和失效分析的要求。 相似文献
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蛋白质定量分析的进展 总被引:10,自引:0,他引:10
陈鸿琪 《理化检验(化学分册)》2000,36(7):333-336
蛋白质是生命的起源,蛋白的定量分析涉及到生产与科研的各领域和与生命有关的许多行业。文中着重阐述了化述法和免疫法在定量分析蛋白质中的应用及发展动态。 相似文献
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设计合成了两种含三氟苯基的新型8-羟基喹啉衍生物配体:(E)-2-[2-(2,4,6-三氟苯基)乙烯基]-8-羟基喹啉(B)、(E)-5-[2-(2,4,6-三氟苯基)亚胺基]-8-羟基喹啉(C)及其相应的锌配合物D与E,产物经NMR,IR,MS,元素分析等进行结构表征。通过核磁、紫外滴定跟踪了金属锌与配体的配位过程,并测定了两者溶液状态下的荧光性质:化合物D,E在甲醇溶液中的荧光发射峰位置分别在599 nm和572 nm处;相比于8-羟基喹啉,2位和5位取代8-羟基喹啉衍生物的荧光发生了明显红移。锌配合物固体荧光寿命的测定结果表明,配合物D表现出较长的荧光寿命。 相似文献
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探讨了我率导数光谱(d^nT/dλ^n)与吸光度导数光谱(d^nA/dλ^n)的关系,并讨论了用d^nT/dλ^n作定量分析的可行性及其产生分析误差的原因以及最佳测量条件。 相似文献
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在氢氧化钠碱性条件下,以端羟基聚丁二烯(HTPB)和环氧氯丙烷(ECH)为原料,四丁基溴化铵(TBAB)为催化剂,制得多羟基聚丁二烯(PHPB)。采用红外光谱(IR)、热重分析仪(TG)、核磁共振(1 H-MNR)对原料、中间产物和产物的结构和热稳定性进行了分析。通过产品的羟值、粘度和产率详细考察了反应温度、反应时间、原料配比、催化剂用量和氢氧化钠用量对PHPB合成的影响。结果表明,最适宜合成工艺条件为:反应温度为55℃,反应时间1.5h,n(HTPB)∶n(ECH)∶n(NaOH)∶n(TBAB)=1∶2.9∶3∶0.03。 相似文献
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最小二乘—红外光谱法定量测定羟基化合物 总被引:2,自引:0,他引:2
根据羟基伸缩振动吸收带的特性,用最小二乘法有效消除了溶液中羟基间的缔合作用对测定结果的影响。此方法已用于聚合物中羟基含量的测定。 相似文献
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Since the finding of organic conductor in 1973 and organic superconductor in 1980, great progress has been achieved1 in the field of organic conductors and superconductors. Much effort is still being devoted to this field, and several significant results have been obtained by subtle modifications of BEDT-TTF, such as, the substitution of peripheral sulfur atoms with selenium ( BETS )2 and oxygen ( BEDO)3atoms, the extra-substitution with hydroxyl , amide, pyridine groups4 etc., all of the… 相似文献
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Leonardo Dalseno Antonino Júlia Rocha Gouveia Rogrio Ramos de Sousa Júnior Guilherme Elias Saltarelli Garcia Luara Carneiro Gobbo Lara Basílio Tavares Demetrio Jackson dos Santos 《Molecules (Basel, Switzerland)》2021,26(8)
Several efforts have been dedicated to the development of lignin-based polyurethanes (PU) in recent years. The low and heterogeneous reactivity of lignin hydroxyl groups towards diisocyanates, arising from their highly complex chemical structure, limits the application of this biopolymer in PU synthesis. Besides the well-known differences in the reactivity of aliphatic and aromatic hydroxyl groups, experimental work in which the reactivity of both types of hydroxyl, especially the aromatic ones present in syringyl (S-unit), guaiacyl (G-unit), and p-hydroxyphenyl (H-unit) building units are considered and compared, is still lacking in the literature. In this work, the hydroxyl reactivity of two kraft lignin grades towards 4,4′-diphenylmethane diisocyanate (MDI) was investigated. 31P NMR allowed the monitoring of the reactivity of each hydroxyl group in the lignin structure. FTIR spectra revealed the evolution of peaks related to hydroxyl consumption and urethane formation. These results might support new PU developments, including the use of unmodified lignin and the synthesis of MDI-functionalized biopolymers or prepolymers. 相似文献
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Zhou-Yan Lv Gang Yang Bao-Ping Ren Zheng-Yan Liu Dr. Hao Zhang Dr. Li-Ping Si Prof. Dr. Hai-Yang Liu Prof. Dr. Chi-Kwong Chang 《欧洲无机化学杂志》2023,26(12):e202200755
Three isomeric A2B-type new cobalt triaryl corroles bearing hydroxyphenyl substituents have been prepared and well characterized. Their activity and stability in the electrocatalytic hydrogen evolution reaction (HER) have been investigated. The results showed that the hydroxyl position of the phenyl group had significant influence on electrocatalytic HER. The ortho-hydroxyphenyl substituted cobalt corrole ( 1 ) core displays the best HER activity using TsOH proton source, and the turnover frequency (TOF) and catalytic efficiency (C.E) reach 318.68 s−1 and 1.13, respectively. Moreover, a turnover number (TON) of 1447.39 and Faraday efficiency (FE) of 98.7 % have been observed in aqueous medium. The catalytic pathway is via EECEC, EECC or ECEC pathways depending on the acidity of acid proton source (E: electron transfer step, C: chemical step, in this case protonation). The catalytic HER performance of these cobalt corroles follows an order of o-hydroxyl > p-hydroxyl > m-hydroxyl isomer, showing the o- and p-hydroxyl of the phenyl groups are more efficient in accelerating proton relay. 相似文献
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The protection and deprotection of functionalgroups are indispensable in the synthesis of polyfunc-tional compounds.In addition,several chemical con-versions and multiple sequence syntheses are often re-quired for the protection of hydroxyl groups.Thesily… 相似文献
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《Analytical letters》2012,45(8):463-470
Abstract A simple method is described for determination of the number of adjacent hydroxyls in an organic compound. This method involves a digestion of the sample with hydriodic acid in a closed tube. The amount of iodine produced in the digestion (i.e., N-1 moles) is related to the number of adjacent hydroxyls in the molecule (i.e., N). 相似文献
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结合国内外各课题组研究,从27Al NMR实验参数和铝形态研究两方面综合评述了液体27Al NMR的发展研究现况。首次明确提出27Al NMR测定中设置合适的预采集延迟时间的作用。将为进一步开展的27Al NMR测定研究提供有价值的参考。 相似文献
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Luc Ubaghs Nicole Fricke Helmut Keul Hartwig Hcker 《Macromolecular rapid communications》2004,25(3):517-521
Communication: Phenoxycarbonyloxymethyl ethylene carbonate 4 was synthesized from glycerol carbonate and phenyl chloroformate. Polyurethanes with pendant hydroxyl groups were obtained from polycondensation reactions of this AA* monomer with diamines. These polymers contain primary as well as secondary hydroxyl groups. The obtained polyurethanes are amorphous materials. The glass transition temperature decreases with increasing number of methylene groups between the urethane groups.