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排序方式: 共有440条查询结果,搜索用时 31 毫秒
71.
我国合成邻苯二甲酸二丁酯用催化剂研究现状 总被引:1,自引:0,他引:1
评述了对甲苯磺酸、氨基磺酸、强酸性阳离子交换树脂、一水硫酸氢钠、五水四氯化锡、氧化锡、稀土化合物、杂多酸和相转移催化剂等催化剂催化合成邻苯二甲酸二丁酯的方法。 相似文献
72.
采用填充柱气相色谱法,选用以OV-101为固定相的玻璃柱,用内标法测定E型电热蚊香片中炔丙菊酯的含量。方法的线性相关系数为0.9999,标准偏差为0.043,变异系数为0.34%,回收范围为99.87%~100.07%。 相似文献
73.
Razan Alaneed Yury Golitsyn Till Hauenschild Markus Pietzsch Detlef Reichert Jrg Kressler 《Polymer International》2021,70(1):135-144
A highly efficient approach for the synthesis of polyester‐based networks via aza‐Michael addition of primary amines to α,β‐unsaturated (vinyl) end groups of poly(glycerol adipate) (PGA) was achieved. By acylation of PGA with 6‐(Fmoc‐amino)hexanoic acid side chains via Steglich esterification, protected amine‐functionalized PGA was obtained. This was followed by the removal of fluorenylmethyloxycarbonyl (Fmoc) protecting groups and the synthesis of PGA‐based networks under catalyst‐free conditions. The successful conjugate addition of primary amines to vinyl end groups and network formation were confirmed using 13C magic angle spinning NMR and Fourier transform infrared spectroscopy. Network heterogeneity and defects were quantitatively investigated using 1H double‐quantum NMR spectroscopy. Finally, a hydrogel was prepared with potential biomedical applications. 相似文献
74.
邻苯二甲酸二丁酯(DBP)具有广泛的工业用途,因此,其有效合成尤为重要。本论文采用气相色谱法检测了邻苯二甲酸二丁酯,并对其合成动力学进行研究。结果表明,气相色谱采用毛细管色谱柱,高纯氮载气流量为2 mL/min,进样口温度240℃,柱温初始温度100℃,并以25℃/min的升温速率升至240℃,该条件能够有效检测邻苯二甲酸二丁酯,以及合成反应中的正丁醇和丁醚。DBP质量分数为10%~60%之间,峰面积与邻苯二甲酸二丁酯含量成正比。另外,研究了以苯酐和正丁醇为原料,采用浓硫酸催化剂合成邻苯二甲酸二丁酯的动力学,反应速率常数4×10^-5 L·mol^-1·min^-1,为邻苯二甲酸二丁酯的有效合成提供了理论依据。 相似文献
75.
Dielectric relaxation measurements are reported on plasticized commercial and heterogeneously substituted cellulose acetate. Differences in the observed behaviour are attributed to the retention of a degree of crystallinity and microscopic structure in the original substituted cellulose samples. A comparison of dynamic mechanical and dielectric relaxation data further emphasizes the influence of the nature of the original morphology on the micro dynamics. 相似文献
76.
Constantine D. Papaspyrides 《Polymer International》1992,29(4):293-298
Low reaction rates and distinct transition phenomena from the solid to the melt state restrain solid state polymerisation (SSP) reactions of nylon salts for industrial application. To alleviate these problems, catalysts containing nylon salts are employed. In this study, hexamethylenediammonium adipate (HMA) particles were used containing a strictly controlled amount of catalyst, either phosphoric acid, sulphuric acid or boric acid. The results show considerable acceleration of the reaction rate, especially in the presence of boric acid, while the solid state character of the process is maintained throughout the total course of the reaction. Comparative polymerisation runs were monitored both by end-group and quantitative water determinations of the reacting material to exclude any accumulation of the water of polycondensation within the reacting particles. The results obtained support further the mechanism proposed for the transition solid-melt in SSP runs of nylon salts in the absence of catalysts. In the latter case extended water accumulation is the rule. 相似文献
77.
The pH-responsive molecularly imprinted polymers (SR-MIPs) for the removal of dibutyl phthalate (DBP) were obtained. The polymers were synthesized using methyl methacrylate, methacrylic acid, divinylbenzene, and a template mixed at different ratios allowing to optimize the process. The so-prepared SR-MIPs were evaluated at various pH values in processes of DBP sorption. The studies covered evaluation of uptake capacity, sorption kinetics, selectivity, and elution. The imprinted samples are characterized by improved factors comparing to their non-imprinted analogues, revealing also pH-sensitivity. The highest removal of DBP (130 mg g?1) was achieved at pH = 6, while pH-driven desorption (90%) was the most efficient at pH = 8. 相似文献
78.
79.
80.
硅钨杂多酸催化合成己二酸二丁酯的研究 总被引:5,自引:1,他引:5
以硅钨杂多酸为催化剂,以己二酸和正丁醇为原料合成了己二酸二丁酯。通过正交实验考察了影响酯化率的各种因素,确定了最佳反应条件为:己二酸用量0.05 mol时,正丁醇与己二酸的物质的量比为2.6,催化剂0.3 g,15 mL甲苯作带水剂,回流温度下反应30 m in,酯化率达99%以上。 相似文献