Aromatic Tetraamines Research Articles

Covalent Organic Frameworks as Negative Electrodes for High‐Performance Asymmetric Supercapacitors

AbstractNew covalent organic frameworks (COFs), encompassing redox‐functionalized moieties and an aza‐fused π‐conjugated system, are designed, synthesized, and deployed as negative electrodes in asymmetric supercapacitors (ASC), for the first time. The Hex‐Aza‐COFs are synthesized based on the solvothermal condensation reaction of cyclohexanehexone and redox‐functionalized aromatic tetramines with benzoquinone (Hex‐Aza‐COF‐2) or phenazine (Hex‐Aza‐COF‐3). The redox‐functionalized Hex‐Aza‐COFs show a specific capacitance of 585 F g−1 for Hex‐Aza‐COF‐2 and 663 F g−1 for Hex‐Aza‐COF‐3 in a three‐electrode configuration. These values are the highest among reported COF materials and are comparable with state‐of‐the‐art pseudocapacitive electrodes. The Hex‐Aza‐COFs exhibit a wide voltage window (0 to −1.0 V), which allow the construction of a two‐electrode ASC device by combining them with RuO2. The complementary potential windows of Hex‐Aza‐COF‐3 and RuO2 enable an asymmetric device with a high voltage window of 1.7 V. The RuO2//Hex‐Aza‐COF‐3 ASC device achieves an energy density value of 23.3 W h kg−1 at a power density of 661.2 W kg−1. The newly developed negative COF materials open new prospects for the development of high‐performance ASCs.

Highly Selective Separation of CO2, CH4, and C2-C4 Hydrocarbons in Ultramicroporous Semicycloaliphatic Polyimides.

Ultramicroporous semicycloaliphatic polyimides with major pore sizes less than 0.5 nm are synthesized through imidization reaction between different aromatic tetraamines and cycloaliphatic dianhydrides. The synergistic role of abundant CO2-philic imide rings and the molecular sieving effect of ultrasmall pores in the polyimide network bring about high adsorption selectivity of CO2/CH4 (37.2) and CO2/N2 (136.7). In addition, it is interesting to observe that, under ambient condition (298 K/1 bar), n-butane exhibits the highest uptake (3.15 mmol/g) among the C1-C4 alkanes, and the adsorbed amount significantly drops with the reduction of the number of carbon atoms. As a result, the mixed light alkanes can be effectively separated according to the carbon numbers. The separation factors of n-butane/propane and propane/ethane reach 3.1 and 6.5, whereas those of n-butane, propane, and ethane over methane are as high as 414.5, 217.4, and 19.6, respectively. Moreover, the polyimides display large adsorption capacities for 1,3-butadiene (4.64 mmol/g) and propene (2.68 mmol/g) with good selectivity over 1-butene and propane of 3.2 and 3.0, respectively. Together with the excellent thermal and physicochemical stabilities, the ultramicroporous polyimides obtained in this work show promising applications in adsorption/separation for CO2, CH4, and C2-C4 hydrocarbons.

Heat-Resistant Network Block Copolymers Based on Rolivsans Modified with Tetracarboxylic Anhydrides and Aromatic Tetraamines

The efficiency of a new approach to structural-chemical modification of unsaturated thermosetting resins was demonstrated by the example of curing of rolivsans containing small additions (0.5–2.0 wt %) of aromatic tetracarboxylic dianhydrides and aromatic tetraamines. As shown by dynamic mechanical and thermal analysis, the heat resistance of the modified matrix of the cured rolivsan, which is mainly used as a heat-resistant polymer compound for electric insulation, increases from 280 to 340–375°С, and the rigidity parameters decrease by a factor of 3–6, which is of much practical interest.

Fluorinated polybenzimidazopyrrolones with excellent alkaline‐hydrolysis resistance

ABSTRACTTwo novel aromatic tetraamines containing bulky lateral phenyl unit and multiple trifluoromethyl groups, 1,1‐bis[4‐(3′,4′‐diaminophenoxy)phenyl]‐1‐(3″‐trifluoromethylphenyl)−2,2,2‐trifluoroethane (6FTA) and 1,1‐bis[4‐(3′,4′‐diaminophenoxy)phenyl]‐1‐[3″,5″‐bis(trifluoromethyl)phenyl]‐2,2,2‐trifluoroethane (9FTA) were synthesized and characterized. A series of fluorinated aromatic polybenzimidazopyrrolones (polypyrrolones, PPys) were synthesized via a two‐step polycondensation procedure. The inherent viscosities of the precursors, poly(amide amino acid) (PAAA), ranged from 0.39 dL/g to 0.54 dL/g. All the FPPys were amorphous. The freestanding FPPy films could be prepared, which exhibited good thermal stability with the glass transition temperature of 315–389°C, the temperatures of 5% weight loss (T5%) of 497–535°C in nitrogen and residual weight retention at 700°C over 60%. All the FPPy films exhibited excellent alkaline‐hydrolysis resistance which retained their original shapes and toughness after boiling 7 days in 10% sodium hydroxide solution. Also after boiling 8 h in 10% sodium hydroxide solution, the tensile strength could retain as high as 56% of the original values. The alkaline‐hydrolysis resistance was much better than the polyimides which had similar chemical structures. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014, 131, 40041.

Fluorene-bridged polyphenylquinoxalines with high solubility and good thermal stability: Synthesis and properties

A novel fluorene-bridged tetraketone monomer, 9,9-bis[(4-benzilyloxy)phenyl]fluorene (FLTK) was synthesized and characterized. The tetraketone was polymerized with various aromatic tetraamines to afford a series of polyphenylquinoxalines (PPQs). The obtained polymers were found to be soluble in common organic solvents such as N-methyl-2-pyrrolidone (NMP), chloroform and m-cresol. Flexible and tough PPQ films obtained by spin-casting their NMP solutions exhibited tensile strengths higher than 60 MPa. The films also demonstrated good thermal stability up to 500°C in nitrogen and glass transition temperatures higher than 280°C. In addition, the PPQ films exhibited good hydrolytic stability. High surface and volume resistivity retentions were achieved for the films after immersion or boiling in water for 24 h.

Synthesis and characterization of organo-soluble thioether-bridged polyphenylquinoxalines with ultra-high refractive indices and low birefringences

Two aromatic tetraketones, 4,4′-thiobis[(p-phenyleneoxy)benzil] (STK, 1) and 4,4′-thiobis[(p-phenylenesulfanyl)benzil] (3STK, 2) were synthesized by the nitro nucleophilic substituent reactions of 4-nitrobenzil and corresponding diol compounds. The two tetraketones were polymerized with three aromatic tetraamines, including 3,3′-diaminobenzidine (a), 3,3′,4,4′-tetraaminodiphenylether (b) and 3,3′,4,4′-tetraaminodiphenylsulfone (c), respectively to afford six thioether-bridged polyphenylquinoxalines (PPQs) – PPQ-1a–1c and PPQ-2a–2c. The obtained PPQs exhibited good solubility not only in conventional m-cresol and chloroform, but in the aprotic solvent – N-methyl-2-pyrrolidinone (NMP). PPQ-1c and 2c containing sulfone units were even soluble in tetrahydrofuran at room temperature with a solid content of 15 wt%. Flexible and tough PPQ films cast from their NMP solution showed good thermal stabilities, including glass transition temperatures in the range of 215–248 °C and 5% weight loss temperatures exceeding 500 °C in nitrogen. The PPQ films at a thickness of ∼10 μm exhibited moderate optical transparency at 450 nm. The best optical transmittance around 80% was achieved by PPQ-1c and 2c containing electron-withdrawing sulfone moieties. The synergic effects of flexible thioether linkages and highly conjugated quinoxaline rings in the present PPQs endowed them with ultra-high refractive indices up to 1.7953 at 632.8 nm and birefringences close to zero.

Multi-Methyl-Substituted Polyphenylquinoxalines with High Solubility and High Glass Transition Temperatures: Synthesis and Characterization

New polyphenylquinoxalines (PPQs) containing methyl substituents have been synthesized and characterized. The PPQs were prepared by the polycondensation of a newly-developed aromatic tetraketone, 4,4′ -bis(4-benzilyloxy)-3,3′,5,5′ -tetramethylbiphenyl (III) and aromatic tetraamines. Compared with the non-methyl-substituted PPQs derived from 1,4-bis (4-benzilyloxy)benzene (I) and 4,4′ -bis(4-benzilyloxy)biphenyl (II), the obtained polymers exhibited better solubility. They were soluble not only in the common m-cresol and chloroform, but in polar aprotic solvent N-methyl-2-pyrrolidinone (NMP). The polymers showed glass transition temperatures of 325°C for PPQ-IIIa (from III and 3,3′,4,4′ -tetraaminobiphenyl) and 287°C for PPQ-IIIb (from III and 3,3′,4,4′ -tetraaminodiphenyl ether), which were much higher than their analogues. The PPQs exhibited good thermal stability up to 470°C in nitrogen and good optical transparency at 450 nm with a thickness of around 10 μ m. The refractive indices and birefringences of the PPQs were in the range of 1.6998–1.7739 and 0.0002–0.0007, respectively.

10.1007/s11498-008-1004-4

New bis(α-diketones) with thiophene and benzothiophene moieties were synthesized. A series of new polyphenylquinoxalines containing these moieties in side chains was prepared via polycondensation of these diketones with different aromatic tetramines. The polymers are soluble in a variety of organic solvents, and their solutions form transparent films having a tensile strength of σ = 80–100 MPa and an elongation at break of ɛ = 5–12%. The polymers exhibit fluorescence in solution in trifluoroacetic acid and in films with a maximum at 430–570 and 460–480 nm. The 10% mass loss temperature in air ranges within 440–490°C.

Synthesis and photophysical properties of polyphenylquinoxalines with thiophene and benzothiophene units in side chains

New bis(α-diketones) with thiophene and benzothiophene moieties were synthesized. A series of new polyphenylquinoxalines containing these moieties in side chains was prepared via polycondensation of these diketones with different aromatic tetramines. The polymers are soluble in a variety of organic solvents, and their solutions form transparent films having a tensile strength of σ = 80–100 MPa and an elongation at break of ɛ = 5–12%. The polymers exhibit fluorescence in solution in trifluoroacetic acid and in films with a maximum at 430–570 and 460–480 nm. The 10% mass loss temperature in air ranges within 440–490°C.

Synthesis and photophysical properties of polyphenylquinoxalines with thiophene and dibenzothiophene units in the backbone

New bis(α-diketones) containing thiophene and dibenzothiophene groups were synthesized. Via the reaction of these monomers with aromatic tetramines under high-temperature polycondensation conditions, a series of new polyphenylquinoxalines combining high thermal and mechanical characteristics with solubility in organic solvents were prepared. Polyphenylquinoxalines exhibit intense fluorescence in solution and in thin films with maxima in the region of 432–522 and 450–530 nm in the case of thiophene-containing and dibenzothiophene derivatives, respectively.

Self-condensation of aromatic tetraamines and their polycondensation with some tetrachloro compounds

Several ladder and partial ladder polymers have been synthesized by self-condensation reactions of 1,2,4,5-tetraaminobenzene, 3,3′,4,4′-tetraaminodiphenylether, 3,3′-diamino-benzidine and 3,3′, 4,4′-tetraaminodiphenyl sulfone in polyphosphoric acid. These products are highly colored and have good thermal stability. Polyquinoxaline or dihydrophenazine or a mixture of these two recurring units seem to form these compounds. These compounds are slightly soluble in methanesulfonic acid and concenterated sulfuric acid and have inherent viscosities in the 0.2–0.4 range. Also, new ladder and partial lader aromatic heteropolymers have been obtained from 1,2,5,6-tetraaminoanthraquinione with 2,3,7,8-tetrachloro-1,4,6,9-tetraazaanthracene, 2,2′,3,3′-tetrachloro-6,6′-diquinoxaline, 2,2′,3,3′-tetrachloro-6,6′-di-quinoxalylether and 2,2′,3,3′-tetrachloro-6,6′-diquinoxalyl sulfone. In these cases poly-condensation was carried out both in solution and in melt. Their inherent viscosities were in the range of 0.1–0.44. These polymers were also highly colored, have good thermal stability, and were soluble in methanesulfonic acid and concentrated sulfuric acid.

Novel High Temperature Polypyrrolones with Asymmetric Biphenyl Moieties in the Main Chain: Synthesis and Characterization

Two novel polypyrrolones (PPys) with asymmetric biphenyl moieties in the main chains have been synthesized from 2,3,3',4'-biphenyl tetracarboxylic dianhydride (a-BPDA) and two aromatic tetra-amines: 3,3',4,4'-tetra-amino biphenyl (TABP) and 3,3',4,4'-tetra-amino diphenyl ether (TADPE) respectively, via soluble poly(amide amino acid) (PAAA) precursors, followed by thermal cyclization at elevated temperatures. The polymerization and curing conditions were studied and confirmed. Asymmetric biphenyl structures endowed the polymers with good combined properties. For example, flexible and tough PPy films with acceptable mechanical properties were obtained. Tensile strengths of higher than 70 MPa and elongations at break of higher than 6% were achieved. The PPy films with a final curing temperature of 350°C exhibited good thermal stability and the 10% weight loss temperatures were 610.3°C for PPy-I, and 607.8°C for PPy-II. The residual weight ratios at 700 °C were higher than 80%. In addition, the PPy films showed good dielectric properties with dielectric breakdown strengths of higher than 100 V · μm -1 and dielectric constants of 3.64 for PPy-I and 3.53 for PPy-II.

Synthesis and properties of 10-hydroxy-10-oxo-10H-10λ5-phenoxaphosphine-2,8-dicarboxylic acid and related polybenzoimidazoles

Oxidation of 10-hydroxy-2,8-dimethyl-10H-10λ5-phenoxaphosphine 10-oxide (1) with potassium permanganate in an alkaline medium afforded 10-hydroxy-10-oxo-10H-10λ5-phenoxaphosphine-2,8-dicarboxylic acid (2). The latter exists as a stable crystal hydrate containing two water molecules. With the aim of examining the possibility of performing the synthesis of polybenzoazoles based on acid 2, the model reaction of the latter with o-phenylenediamine in polyphosphoric acid (PPA) was studied. New high-molecular-weight phosphorus-containing polybenzoimidazoles were prepared by the reaction of 2 with various aromatic tetraamines in PPA and Eaton’s reagent.

Synthesis and characterization of new polybenzimidazopyrrolones derived from pyridine‐bridged aromatic tetraamines and dianhydrides

AbstractA series of new polybenzimidazopyrrolones (polypyrrolone, PPy) were synthesized by polycondensation of pyridine‐bridged aromatic tetraamines, including 2,6‐bis (3′,4′‐diaminophenyl)‐4‐phenylpyridine and 2,6‐bis(3′,4′‐ diaminophenyl)‐4‐(3″‐trifluoromethyl)phenyl pyridine, with various aromatic dianhydrides. Experimental results indicated that the PPys, multiaromatic conjugated and semiladder polymers, showed good thermal stabilities with thermal‐decomposition temperatures of about 500 °C and residual weight retention at 750 °C as high as 84%. PPy films could be obtained by casting the precursor solution, poly(amide amino acid) on glass substrate, followed by thermal dehydrating at elevated temperatures. The polymer films exhibited excellent alkaline hydrolysis resistance, which retained their original shapes and toughness after boiling 7 days in 10% sodium hydroxide solution. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1845–1856, 2004

Synthesis and characterization of new thermally stable polybenzimidazoles and poly(amide-benzimidazole)s

Benzofuro[2,3-b]benzofuran-2,9-dicarboxyl-bis-phenylamide-4,4 ′-dicarboxylic acid was synthesized as a new monomer, and characterized by means of IR, 1 HNMR and MS spectroscopy. A series of polybenzimidazoles (PBIs) were prepared from this diacid that were considered as poly(amide-benzimidazole)s and also, some new PBIs were synthesized from benzofuro[2,3-b]benzofuran-2,9-dicarboxylic acid and several aromatic tetraamines by solution polymerization method in polyphosporic acid as solvent. Thermal properties of these polymers were compared. The results showed that all of the PBIs had good thermal stabilities.

Low-Temperature Route to 1, 2-Benzoylenebenzimidazole Ladder Structure

Low-temperature catalytic conversion of N-( o-aminophenyl)phthalamic acid (I) was studied as a model reaction for the synthesis of ladder poly(aroylenebenzimidazole)s. The treatment of I with acetic anhydride/pyridine or trifluoroacetic anhydride resulted in the selective and quantitative cyclodehydration to yield either imide or isoimide structures respectively. The imidization was accompanied by acylation of the ortho amino group to form lateral acetamide or trifluoroacetamide substitutes. Thermodynamically unstable N-( o-trifluoroacetamidophenyl)phthalisoimide (III) underwent secondary cyclization to yield ladder 1, 2-benzoylenebenzimidazole (V) between 130 and 150 °C. The conversion of this reaction did not exceed 35% because it competed with the thermal isomerization of III to the stable N-( o-trifluoroacetamido-phenyl)phthalimide (IV). The cyclization of N-( o-trifluoroacetamidophenyl)phthalisoimide (III) was found to be possible even at room temperature. The formation of 30–35% of the ladder 1, 2-benzoylene-benzimidazole (V) was observed after III was dissolved in DMF and stored at room temperature for 4–10 h. This also was accompanied by the catalytic isoimide-to-imide isomerization. The obtained data may be useful for the further development of novel low-temperature approaches to the synthesis of ladder poly(aroylenebenzimidazole)s. Synthesis of aromatic polyimides and polyisoimides with lateral alkylamide or trifluoroalkylamide from available aromatic dianhydrides and tetraamines may also be of practical interest.

New semiladder polymers. Part II: Synthesis and properties of new poly(amideimidazopyrrolones)

A series of polymers from new diamidedianhydrides of arylene-di(benzene-5-amido-1,2-dicarboxylic) anhydride type and aromatic tetraamines (3,3′-diaminobenzidine and 3,3′,4,4′-tetraaminodiphenylether) were synthesized using one step high temperature polycondensation in m-cresol and p-chlorophenol at 180°C and low temperature polycondensation. The polymers had a semiladder structure. The influence of the monomer structure and polycondensation method on the polymer properties has been investigated.

Polybenzimidazoles, new thermally stable polymeres

Wholly aromatic polybenzimidazoles were synthesized from aromatic tetraamines and difunctional aromatic acids and characterized as new thermally stable polymers. The melt polycondensation of aromatic tetraamines and the diphenyl esters of aromatic dicarboxylic acids was developed as a general procedure of wide applicability. Polybenzimidazoles containing mixed aromatic units in the chain backbone were prepared from 3,3′-diaminobenzidine, 1,2,4,5-tetraaminobenzene and a variety of aromatic diphenyl dicarboxylates. Phenyl 3,4-diaminobenzoate could also be polymerized by melt condensation to give poly-2,5(6)-benzimidazole. The polymers were characterized by a high degree of stability, showing great resistance to treatment with hydrolytic media and an ability to withstand continued exposure to elevated temperatures. Most of the polymers were infusible, but some had melting points above about 400°C. Many of the polymers exhibited no change in properties on being heated to 550°C, and showed a weight loss of less than 5% when heated under nitrogen for several hours to 600°C. The polymers were soluble in concentrated sulfuric acid and formic acid, producing stable solutions. Many of the polymers were soluble in dimethyl sulfoxide and some also in dimethylformamide. The inherent viscosities of a number of polymers in 0.5% dimethyl sulfoxide solution ranged from approximately 0.4 to 1.1. The higher polymers could be cast into stiff and tough films from formic acid and dimethyl sulfoxide solutions.

Preparation of soluble polyimides containing pendent imide groups

Polyimides containing imide and (p-phenoxy)imide side groups were obtained by the interaction of new aromatic tetramines, bis[3-amino-4-(p-aminophenoxy)]arylenes, with equimolar amounts of aromatic tetracarboxylic acid dianhydrides and twofold molar amounts of aromatic dicarboxylic acids anhydrides. Structures and properties of the final polyimides depend on the nature of starting monomers and subsequent introduction of monomers to the reaction mixtures. Polyimides thus obtained demonstrate good solubility in organic solvents, high glass transition temperatures and good stability.

The synthesis and investigation of thermostable soluble polybenzazoles

AbstractThe poly(benzimidazole)s and poly(amidobenzimidazole)s produced on the base of different tetramines, diphenylate of dicarboxylic acids, and ε‐caprolactam or diamines are investigated. In the synthesis were used 3,3′‐diaminobenzidine or aromatic tetramines containing methylene, oxygen, or sulfon groups between the benzene cycles. The produced polymers are thermostable, soluble, and have high enough molecular weights.