活性聚合法合成结构精确的含氟嵌段共聚物

结构精确的含氟嵌段共聚物具有优异而独特的化学和物理性能,有广阔的应用前景,因此受到广泛的关注.含氟嵌段共聚物可分为两类,一类是侧基含氟嵌段共聚物,另一类是主链含氟嵌段共聚物.活性聚合为嵌段共聚物的合成提供了最为重要的方法,利用它可以合成结构精确、分子量可控、分子量分布窄的嵌段共聚物.根据单体的反应特性选择不同的聚合方法,可以得到不同的含氟嵌段共聚物.本文主要综述了近几年利用各种活性聚合方法合成结构精确的含氟嵌段共聚物方面的进展.     

Synthesis of novel enantiopure fluorinated building blocks from acyclic chiral allylsilanes

[reaction: see text] Homochiral beta-fluorinated gamma,delta-unsaturated carboxylic acids with an allylic fluorinated stereogenic center are available from the corresponding enantiopure allylsilanes. The key step for introduction of the fluorine substituent is an electrophilic fluorodesilylation reaction carried out in the presence of Selectfluor. Reduction of the resulting beta-fluorinated pentenoic acid into the corresponding fluorinated alcohol was also performed leading to the formation of an enantiopure second-generation fluorinated building block.     

Synthesis of novel perfluoroalkyl ether derivatives

A series of novel fluoroether-containing monomers has been designed and prepared based on the commercially available perfluoroalkyl ether acid fluoride. Treating acid fluoride with allyl alcohol, 2-hydroxyethyl methacrylate or N-allylmethylamine allowed for the direct formation of corresponding vinyl-containing fluorinated monomers. High yields of the fluorinated epoxy monomers could be obtained from acid chloride with glycidol; meanwhile, fluorinated diol was prepared from diethanolamine or 3-amino-1,2-propanediol. Moreover, fluorinated monoamine, fluorinated monoalcohol and fluorinated dichloride were also obtained. Most of these fluorinated monomers were liquid at room temperature and exhibited good solubility in common organic solvents.     

Synthesis of Highly Functionalized Fluorinated Porphyrins

Highly functionalized fluorinated porphyrins were synthesized by a convergent strategy. Nucleophilic substitution using fluorinated branched unit and 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin afforded highly functionalized fluorinated porphyrin 8 containing 24 fluorinated chains in the peripheral region.     

核壳型含氟丙烯酸酯共聚物的合成及性能

采用饥饿态半连续种子乳液聚合方法, 在十二烷基硫酸钠(SDS)/辛基苯基聚氧乙烯醚(TX-10)复合乳化剂的作用下, 分别选用甲基丙烯酸三氟乙酯(TFEM)、甲基丙烯酸六氟正丁酯(HFBM)和甲基丙烯酸十二氟庚酯(DFHM)为含氟单体, 合成以丙烯酸正丁酯(BA)、甲基丙烯酸甲酯(MMA)和含氟单体为原料的核壳型结构含氟丙烯酸酯共聚物乳液. FTIR, 1H NMR, TEM和DSC分析结果显示, 获得了BA/MMA/含氟单体的共聚物乳液, 且乳液具有明显的核壳结构. DSC, TGA和SEM-EDX的分析显示, 核壳型结构的共聚物具有优异的热力学稳定性能和成膜性能; 长侧链或短侧链含氟单体对共聚物的热稳定性影响不明显, 但侧链较长的含氟单体所获得的聚合物在成膜过程中更易向表面迁移, 更能体现含氟聚合物的优点.     

光固化含氟聚合物的合成进展

综述了自由基光固化和阳离子光固化含氟聚合物的合成进展,并对其进行了讨论.     

含氟聚氨酯的研究进展

综述了溶剂性、水性含氟聚氨酯的合成及研究，并进行了讨论。     

Synthesis of chiral quaternary fluorinated cyclic sulfamidates via palladium-catalyzed arylation with arylboronic acids

An enantioselective palladium-catalyzed arylation of fluorinated cyclic N-sulfonyl ketimines with arylboronic acids is described. This methodology provides an efficient and convenient route to chiral quaternary fluorinated cyclic sulfamidates in high yields with up to 99% ee.     

Synthesis and applications of novel fluorinated dendrimer-type copolymers by the use of fluoroalkanoyl peroxide as a key intermediate

Fluoroalkanoyl peroxide reacted with 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (TTRV-Si) to afford fluoroalkyl end-capped oligomers containing some unreacted vinyl segments under very mild conditions. Fluoroalkyl end-capped cyclosiloxane oligomers containing some vinyl segments thus obtained reacted with N,N-dimethylacrylamide and fluoroalkanoyl peroxide to afford new fluorinated dendrimer-type block copolymers in good isolated yield. Similar reactions were also occurred by the use of 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane instead of TTRV-Si, and the corresponding fluorinated dendrimer-type block copolymer was obtained in good isolated yield. These fluorinated dendrimer-type block copolymers had an excellent solubility not only in water but also in traditional organic solvents including aliphatic fluorinated solvents. Interestingly, these fluorinated block copolymers were found to form the self-assembled dendrimer-type polymeric aggregates in aqueous solutions. More interestingly, these fluorinated block copolymers had an extremely higher dispersion ability of not only single-walled carbon nanotube and fullerenes but also magnetic nanoparticles into water, compared to that of the corresponding two fluoroalkyl end-capped oligomers.     

超临界二氧化碳中含氟聚合物的合成

超临界二氧化碳是廉价、低毒、不易燃、易回收、环境友好的惰性聚合介质,是传统有机溶剂的替代品。尤其是有望成为含氟单体的聚合溶剂,以替代目前使用的氟氯烃。本文详细地介绍了近年来以超临界二氧化碳为介质的氟烷基丙烯酸酯类单体和氟烯烃类单体的聚合反应研究,其中涉及氟烷基丙烯酸酯类单体的均聚和共聚,可熔融加工的四氟乙烯聚合物,离子交换树脂,偏氟乙烯的均聚和共聚合等。研究表明在超临界二氧化碳中的含氟单体的聚合反应有其它溶剂体系无法比拟的优点。     

Metal‐Free Synthesis of Fluorinated Indoles Enabled by Oxidative Dearomatization

Nitrogen heterocycles are found in a majority of approved small‐molecule pharmaceuticals, and the number of approved fluorinated drugs is increasing each decade. Therefore, new approaches for accessing fluorinated nitrogen heterocycles are of great significance. A novel, scalable, and metal‐free method for accessing a wide range of fluorinated indoles is described. This oxidative‐dearomatization‐enabled approach assembles 2‐trifluoromethyl NH‐indole products from simple commercially available anilines with hexafluoroacetylacetone in the presence of an organic oxidant. The nature of the aniline N‐capping group is critical for the success of this new reaction. Furthermore, the indole products contain a 3‐trifluoroacetyl group, which can be exploited to access a plethora of useful functional groups.     

Synthesis of fluorinated α-diketones and some intermediates

Reactions of perfluoroalkylcopper compounds with α-ketoacyl chlorides were used for the synthesis of fluorinated α-diketones. Heptafluoropropylcopper prepared from copper bronze and 1-iodoheptafluoropropane reacted with benzoylformyl chloride to give heptafluoro-1-phenyl-1,2-pentanedione, with trimethylpyruvyl chloride to give 2,2-dimethyl-5,5,6,6,7,7,7-heptafluoro-3,4-heptanedione, and with 3,3,4,4,5,5,5-heptafluoro-2-ketopentanoyl chloride or oxalyl chloride to give tetradecafluoro-4,5-octanedione. Syntheses of fluorinated acetylenes, cyanohydrins, α-hydroxy acids, α-keto acids, their chlorides, and other intermediates for the syntheses of α-diketones by the above route and by other methods are described. An interesting seven-membered ring containing β-hydroxy ketone was obtained by an intramolecular aldol condensation of a fluorinated bis(methyl) ketone.     

Synthesis of fluorinated biphenyls via aryne reaction

Synthesis of fluorinated biphenyls via attack of a benzyne by an anion of 3-fluoroanisole.     

A Modified Synthesis of Fluorinated 1,3-Diketones

The reinvestigation of acylation reactions of fluorinated aryl methylketones with ethyl esters at 0°C afforded fluorinated 1, 3-diketones in excellent yields.     

Synthesis of New Fluoropolymers: Tailoring Macromolecular Properties with Fluorinated Substituents

The challenges and opportunities in the preparation of new fluoro- polymers are illustrated by the synthesis of fluorinated poly(ether sulfones), polyimides, and polyethers. Synthetic methods used for the preparation of new fluorinated monomers and polymers include anion-radical substitutions of perfluoroalkyl diiodides, nucleophilic additions to fluorinated olefins, perfluoroalkylsulfonyl-mediated nucleophilic sub-stitutions, and direct fluorinations with elemental fluorine. Properly placed fluorinated substituents can have significant effects on the dielectric properties, thermal stability, moisture absorption, permeability, phase transitions, and reactivity of the resulting polymers. In addition, fluorinated groups can enhance nonlinear optical effects and provide a method for chromophore alignment. The special behavior of partially fluorinated substituent groups offers unique tools for tailoring macro-molecular properties.     

Synthesis of fluorinated naphthylphenylacetylenic and naphthylphenyldiacetylenic liquid crystals

Four series of fluorinated tolanes, naphthylphenylacetylenes and naphthylphenyldiacetylenes were prepared and characterized. Most of the fluorinated tolanes exhibit no mesomorphic behaviour. However, most of the fluorinated naphthylphenylacetylenes and naphthylphenyldiacetylenes form enantiotropic nematic phases. The dielectric anisotropy and birefringence of some selected compounds were measured by a guest-host method. All of those studied show relatively high dielectric anisotropy and birefringence.     

Synthesis and characterization of fluorinated polyurethane with fluorine-containing pendent groups

A novel fluorinated polyurethane （FPU） with fluorine-containing pendent groups was prepared by using fluorinated polyether glycol （PTMG-g-HFP） as a soft segment, 1,6-hexamethylene diisocyanate （HDI） or toluene diisocyanate （TD1） as a hard segment and 1,4-butanodiol （BDO） as a chain extender. FTIR, ^1H NMR, ^13C NMR and GPC were used to characterize the structure of the fluorinated polyurethane. Thermal stabilities of the fluorinated polyurethane and the corresponding hydrogenated polyurethane were studied by TGA. XPS analysis at two different sampling depths for the fluorinated polyurethane was used to investigate the surface compositions of FPU. The results showed the fluorine enrichment on the surface of FPU.     

Synthesis and mesomorphic properties of some bisegmented compounds derived from 4,4'-disubstituted biphenyl

New unsymmetrical disubstituted biphenyls have been synthesized. Two different chains (one hydrocarbon and the other fluorinated) are linked through an acetamide bond to 4-methoxy-4'-hydroxybiphenyl. Their mesomorphic properties have been characterized by light microscopy and by differential thermal analysis showing the peculiar contribution of the hydrocarbon chain and the fluorinated tail. The enhancement of the hydrocarbon moiety from one to twelve methylene groups leads to a decrease of the clearing temperatures; furthermore the enantiotropic behaviour is changed to monotropic. The variation of the fluorinated moiety generates strong effects on the transition temperatures. These mesomorphic properties are compared to those of their monocatenar perfluorinated analogues incorporating a connector of the ester or monosubstituted amide type.     

Synthesis and properties of new polyimides containing flourinated alkoxy side chains

A series of new polyimides containing fluorinated alkoxy side chains are prepared from novel fluorinated alkoxy diamines. The dieletric constant at 1 kHz in the fluorinated polyimides decreases from 3.3 to 2.6 as fluorine content increases. The refractive index also changes from 1.58 to 1.48, dependent on the fluorine content. In addition, the fluorinated polyimides exhibit lower water absorption than the reference polyimides prepared from m-phenylenediamine.     

Synthesis of Novel Fluorinated [sgrave]-Conjugated Silicon-Containing Polymers: Polysilynes and Polysilanes

Abstract

The synthesis of fluorinated polysilynes, a new class of silicon-silicon network materials, has been achieved by reductive coupling of fluorinated trichlorosilanes with molten sodium in a mixture of toluene and diglyme (4:1) as a new synthetic route. Homopolysilynes containing fluorinated organogroups were insoluble in organic solvents due to side reactions. To improve solubility, copolysilynes were synthesized by co-polymerization of fluorinated trichlorosilanes with cyclohexyltrichlorosi-lane. All spectroscopic data indicate that the structure of the resulting fluorinated copolysilynes is a rigid, irregular network of monoalkyl sp ³-hybridized silicon units which exhibit extensive Si-Si [sgrave]-delocalization. They are more thermally stable than unfluorinated polysilynes. Upon exposure to deep-UV radiation in air, they undergo photooxidative crosslinking to give insoluble glass-like materials. This photooxidation process is accompanied by a large decrease in refractive index from n = 1.61 to n = 1.485. These results suggest that their potential applications include photoresists and optical waveguides. In order to understand the mechanism of reductive coupling of fluorinated trichlorosilanes, fluorinated linear polysilanes were also prepared.