A facile method for the synthesis of 2,3,3＇,4＇-biphenyltetracarboxylic dianhydride（a-BPDA） was reported,which comprises the steps of the dehalogenative coupling of dimethyl 4-chlorophthalate（4-DMCP） and dimethyl...A facile method for the synthesis of 2,3,3＇,4＇-biphenyltetracarboxylic dianhydride（a-BPDA） was reported,which comprises the steps of the dehalogenative coupling of dimethyl 4-chlorophthalate（4-DMCP） and dimethyl 3-chlorophthalate（3-DMCP） catalyzed by low-cost（Ph 3 P） 2 NiCl 2,the hydrolysis of tetra-ester and the dehydration of tetra-acid.In contrast to the conventional methods,this method has the advantage of low cost,convenient manipulation,available condition,high purity and good overall yield.Moreover,the single crystal structure of a-BPDA was analyzed by X-ray diffraction method.The X-ray data suggest that a-BPDA is a rigid,non-coplanar and non-linear structure.It contains three crystallographically independent molecules,in which the dihedral angles of the two linked phenyl rings are 44.75（4）°,46.37（3）° and 42.32（3）°,respectively.The title molecule is governed by a stronger intermolecular interaction in contrast to van der Waals interaction because of the special positions of anhydride groups.展开更多
A novel approach to the synthesis of 2,2＇,3,3＇-biphenyltetracarboxylic dianhydride is described. The target compound was prepared by a nickel-catalyzed couplirtg reaction of dimethy 3-chlorophthalate （3-DMCP） for ...A novel approach to the synthesis of 2,2＇,3,3＇-biphenyltetracarboxylic dianhydride is described. The target compound was prepared by a nickel-catalyzed couplirtg reaction of dimethy 3-chlorophthalate （3-DMCP） for 4 h at 70-80 ℃, followed by subsequent hydrolysis of tetra-ester in acid solution and dehydration of tetra-acid, with overall yield of 68%. The structures of the products were characterized by IR, 1H NMR and ^13C NMR respectively.展开更多
Polyimides have been widely used in aerospace and mi- croelectronics due to their excellent mechanical properties and thermo oxidative stability^[1]. However, most of aromatic polyi- mides are severe difficult to proc...Polyimides have been widely used in aerospace and mi- croelectronics due to their excellent mechanical properties and thermo oxidative stability^[1]. However, most of aromatic polyi- mides are severe difficult to process because of their bad solu- bility in common solvents and intractable in their fully imidized forms, which restrict their applications and developments^[2,3]. Therefore, many investigations were focused on improving the dissolvability of polyimides and it was found that the excellent solubilizing units could be obtained from substituted biphenyls^[4-7]. Biphenyltetracarboxylic dianhydrides（BPDAs） are the most important monomers for the synthesis of these compounds. Among them, the synthesis of 2,3,3＇,4＇-/3,3＇,4,4＇- biphenyltetracarboxylic dianhydride has been widely investi- gated, but only a few literatures reported the synthesis of 2,2＇,3,3＇-biphenyltetracarboxylic dianhydride（i-BPDA）^[8-10].展开更多
The properties of a series of imide oligomers were characterized according to their molecular weights, solubility, and thermal and rheological properties. This series of imide oligomers was synthesized via a two-step ...The properties of a series of imide oligomers were characterized according to their molecular weights, solubility, and thermal and rheological properties. This series of imide oligomers was synthesized via a two-step method using 2,2′,3,3′-biphenyltetracarboxylic dianhydride(3,3′-BPDA) and aromatic diamines as the monomers, and 4-phenylethynyl phtlialic anhydride(PEPA) as the end-capping agent. The imide oligomers based on 3,3′-BPDA showed excellent solubility in low boiling point solvents and low melt viscosity, which were attributed to their unique bent architectures. High-performance thermosetting polyimides were produced from these oligomers via thermal crosslinking of the phenylethynyl groups. The mechanical and thermal properties of the thermosets were studied using tensile testing, dynamic mechanical thermal analysis(DMTA), and thermogravimetric analysis(TGA). The 3,3′EPDA-based thermosets exhibited excellent thermal properties, with glass transition temperatures of up to 455℃, and 5% mass loss temperatures of up to 569℃ in air. The thermosets based on 3,3-BPDA showed superior thermal properties compared to those derived from TriA-X series oligomers.展开更多
导电聚合物材料具有原料价格低廉、比重轻、具可塑性、微结构便于控制等优点,在锂离子电池方面具有应用的潜力.聚萘是一种良好的导电高分子,它具有许多优良的光电性能.该文以3,4,9,10-二苯四甲酸酐为原料,在一定条件下,经高温煅烧合成...导电聚合物材料具有原料价格低廉、比重轻、具可塑性、微结构便于控制等优点,在锂离子电池方面具有应用的潜力.聚萘是一种良好的导电高分子,它具有许多优良的光电性能.该文以3,4,9,10-二苯四甲酸酐为原料,在一定条件下,经高温煅烧合成一种石墨状聚萘,并以这种石墨状聚萘为锂离子电池正极材料,对其进行探索性研究.通过红外光谱、拉曼光谱、热失重、扫描电镜等分析手段,对合成的石墨状聚萘做了相应的结构和外貌表征;利用恒流充放电、循环伏安和交流阻抗等电化学方法来研究石墨状聚萘的电化学性能.结果表明,通过上述合成方法,成功合成了石墨状聚萘,经电化学性能测试发现石墨状聚萘有较大的放电容量、良好的循环稳定性,在电流密度为100 m Ah·g-1的条件下,首次放电容量高达281.3 m Ah·g-1,100次循环后,容量仍保持在188.4 m Ah·g-1,容量保持率高达66.97%.因此,石墨状聚萘是一种较为理想的锂离子电池的正极材料.展开更多
基金Supported by the Ministry of Education Project Combining the Industry and Teaching with Research of Guangdong Province,China(No.2011B090400062)
文摘A facile method for the synthesis of 2,3,3＇,4＇-biphenyltetracarboxylic dianhydride（a-BPDA） was reported,which comprises the steps of the dehalogenative coupling of dimethyl 4-chlorophthalate（4-DMCP） and dimethyl 3-chlorophthalate（3-DMCP） catalyzed by low-cost（Ph 3 P） 2 NiCl 2,the hydrolysis of tetra-ester and the dehydration of tetra-acid.In contrast to the conventional methods,this method has the advantage of low cost,convenient manipulation,available condition,high purity and good overall yield.Moreover,the single crystal structure of a-BPDA was analyzed by X-ray diffraction method.The X-ray data suggest that a-BPDA is a rigid,non-coplanar and non-linear structure.It contains three crystallographically independent molecules,in which the dihedral angles of the two linked phenyl rings are 44.75（4）°,46.37（3）° and 42.32（3）°,respectively.The title molecule is governed by a stronger intermolecular interaction in contrast to van der Waals interaction because of the special positions of anhydride groups.
基金the National Undergraduates' Innovative Experiment Project of Chinathe Undergraduates' Innovative Experiment Project of Sichuan University for financial support.
文摘A novel approach to the synthesis of 2,2＇,3,3＇-biphenyltetracarboxylic dianhydride is described. The target compound was prepared by a nickel-catalyzed couplirtg reaction of dimethy 3-chlorophthalate （3-DMCP） for 4 h at 70-80 ℃, followed by subsequent hydrolysis of tetra-ester in acid solution and dehydration of tetra-acid, with overall yield of 68%. The structures of the products were characterized by IR, 1H NMR and ^13C NMR respectively.
基金Supported by the Project of Sichuan University of Science and Technology,China(No.11-26)the Ministry of Education Project Combining the Industry and Teaching with Research of Guangdong Province,China(No.2011B090400062)
文摘Polyimides have been widely used in aerospace and mi- croelectronics due to their excellent mechanical properties and thermo oxidative stability^[1]. However, most of aromatic polyi- mides are severe difficult to process because of their bad solu- bility in common solvents and intractable in their fully imidized forms, which restrict their applications and developments^[2,3]. Therefore, many investigations were focused on improving the dissolvability of polyimides and it was found that the excellent solubilizing units could be obtained from substituted biphenyls^[4-7]. Biphenyltetracarboxylic dianhydrides（BPDAs） are the most important monomers for the synthesis of these compounds. Among them, the synthesis of 2,3,3＇,4＇-/3,3＇,4,4＇- biphenyltetracarboxylic dianhydride has been widely investi- gated, but only a few literatures reported the synthesis of 2,2＇,3,3＇-biphenyltetracarboxylic dianhydride（i-BPDA）^[8-10].
基金the Technology Innovation Fund of Chinese Academy of Sciences(NO.CXJJ-17-M159)the National Natural Science Foundation of China(No.51473157).
文摘The properties of a series of imide oligomers were characterized according to their molecular weights, solubility, and thermal and rheological properties. This series of imide oligomers was synthesized via a two-step method using 2,2′,3,3′-biphenyltetracarboxylic dianhydride(3,3′-BPDA) and aromatic diamines as the monomers, and 4-phenylethynyl phtlialic anhydride(PEPA) as the end-capping agent. The imide oligomers based on 3,3′-BPDA showed excellent solubility in low boiling point solvents and low melt viscosity, which were attributed to their unique bent architectures. High-performance thermosetting polyimides were produced from these oligomers via thermal crosslinking of the phenylethynyl groups. The mechanical and thermal properties of the thermosets were studied using tensile testing, dynamic mechanical thermal analysis(DMTA), and thermogravimetric analysis(TGA). The 3,3′EPDA-based thermosets exhibited excellent thermal properties, with glass transition temperatures of up to 455℃, and 5% mass loss temperatures of up to 569℃ in air. The thermosets based on 3,3-BPDA showed superior thermal properties compared to those derived from TriA-X series oligomers.
文摘导电聚合物材料具有原料价格低廉、比重轻、具可塑性、微结构便于控制等优点,在锂离子电池方面具有应用的潜力.聚萘是一种良好的导电高分子,它具有许多优良的光电性能.该文以3,4,9,10-二苯四甲酸酐为原料,在一定条件下,经高温煅烧合成一种石墨状聚萘,并以这种石墨状聚萘为锂离子电池正极材料,对其进行探索性研究.通过红外光谱、拉曼光谱、热失重、扫描电镜等分析手段,对合成的石墨状聚萘做了相应的结构和外貌表征;利用恒流充放电、循环伏安和交流阻抗等电化学方法来研究石墨状聚萘的电化学性能.结果表明,通过上述合成方法,成功合成了石墨状聚萘,经电化学性能测试发现石墨状聚萘有较大的放电容量、良好的循环稳定性,在电流密度为100 m Ah·g-1的条件下,首次放电容量高达281.3 m Ah·g-1,100次循环后,容量仍保持在188.4 m Ah·g-1,容量保持率高达66.97%.因此,石墨状聚萘是一种较为理想的锂离子电池的正极材料.
