Aromatic Dihalides Research Articles

POLYARYLENEETHERKETONES OBTAINING WITH REACTION OF NUCLEOPHILIC SUBSTITUTION

The article deals with the study of influence of the synthesis conditions on the molecular weight of polyaryleneetherketones (PAEK), received with nucleophilic substitution reaction of activated aryl halide. The synthesis of PAEK with the nucleophilic substitution reaction carried out as partially hydrolyzed homopolycondensation of phenolates and aromatic dihalides containing a carbonyl group in the molecule and derivatives of polycondensation of aromatic bisphenols with activated aromatic dihalides, and aromatic nitro compounds. The nucleophilic substitution of halogen in aryldihalogens proceeds through formation of Meisenheimer complex, where the negative charge of the electron-electron ring stabilizes the group. The high efficiency of the synthesis of PAEK with nucleophilic substitution reaction is mainly determined with several factors, the main of which are: 1) the structure of the starting monomers; 2) the nature of the solvent; 3) the nature of phenolate; 4) side reactions. For these materials it was revealed that the ratio of nucleophilic and electrophilic reagents has pronounced effect on the molecular weight of the obtained polymer, without affecting the poly dispersion. PAEK synthesis processes are optimized by controlling the replacement of some of the monomers, the temperature and concentration of reactants change. It was shown that the polyarylene ether ketones and copolymers have a high thermal heat resistance, mechanical properties. They show considerable heat resistance in air, capable of forming a transparent film and melts. Thus, data of literature review show that the nucleophilic substitution reaction is promising for PAEK synthesis of various chemical structures and produces polymers having valuable properties.

Alkylated sulfonated poly(arylene sulfone)s for proton exchange membranes

The attachment of flexible spacers into aromatic polymers is a molecular design approach that is used for improving processability of aromatic polymers. The concept is attractive because it enables not only the creation of aromatic polymers with improved processability but it is also possible to control phase morphology by simply introducing pendant side chains. Here we report new bisphenol A derivatives bearing alkyl chains of different lengths obtained by an addition reaction can readily make novel poly(arylene sulfone)s with aromatic dihalides and aromatic dioles. They were observed using two-dimension diffusion-ordered spectroscopy nuclear magnetic resonance (2D DOSY NMR) spectra. Attaching flexible alkyl groups into sulfonated poly(arylene sulfone)s allows for increased control of glass transition temperatures, T g , of sulfonated poly(arylene sulfone)s. The alkylated sulfonated poly(arylene sulfone)s had flexibility, increased surface contact angle, improved methanol permeability, and high ion conductivity compared to the neat polymer. Due to the creation of aromatic polymers with improved processability by simply introducing pedant side chains, this novel alkylation method is expected to be applicable to other arylene based proton conductive polymers.

A revisit to the Gattermann reaction: interesting synthesis of nitrogen heterocyclic aromatic halides and their fluorescence properties

The Gattermann reaction and an electrophilic substitution reaction, which were conducted in a one-pot reaction, are reported, and four aromatic dihalides of similar structure were obtained. 2-Chloro-5-(3-chloro-4-methoxy-phenyl)-1,3,4-thiadiazole was applied as a highly efficient fluorescence sensor for the detection of TNP.

Synthesis of Triptycene-Substituted Azapentacene and Azahexacene Derivatives.

We describe the synthesis and characterization of novel iptycene-substituted azaacenes by using either a classic condensation route (diamine plus ortho-quinone) and/or a Pd-catalyzed coupling of an aromatic diamine with an aromatic dihalide. The attachment of an iptycene unit leads to a significant blueshift (15 nm) in the UV/Vis spectra of these azaacenes. The iptycene unit stabilizes a hexaazahexacene with a λmax abs of 833 nm. By employing 5,6-diamino(benzothiadiazole) as a synthon for tetraaminobenzene, we could prepare the symmetrical bis-triptycene-substituted tetraazapentacene in high yields.

ChemInform Abstract: The Palladium Way to N‐Heteroacenes

AbstractReview: [25 refs.

The Palladium Way to N-Heteroacenes.

Novel synthetic methodologies allow increasingly efficient access to known organic materials, as well as the preparation of otherwise inaccessible species. Pd-catalyzed coupling of aromatic dihalides to ortho-diaminoarenes furnishes embedded stable N,N'-dihydropyrazines expediently and in often excellent yields. The embedded N,N'-dihydropyrazines can then be oxidized by MnO2 to give substituted azatetracenes, azapentacenes, azahexacenes, and azaheptacenes, which are soluble, processable, and stable. This powerful Pd-catalyzed methodology allows the preparation of azaacenes, including diaza-, tetraaza- and hexaazaacenes. In combination with a suitable Pd precursor, Buchwald-type biarylphosphines have been shown to give excellent results. Activated dihalides such as 2,3-dihaloquinoxalines are coupled easily under simplified conditions, whereas 2,3-dibromoacenes require more stringent conditions and advanced catalyst precursors. Pd catalysts effect the assembly of azaacenes with otherwise difficult to obtain substitution patterns. High yields and flexibility make this method most attractive.

Recent advances in the preparation of functionalized polysulfones

AbstractThis review summarizes the studies related to chemical functionalization of polysulfones used in many different applications such as membranes with special functions, nanocomposites, biofilm formation, fuel cells etc. reported in recent years from the literature since 2000. Various strategies have been applied for the functionalization of polysulfones. One strategy is to add desired functionality into starting monomers in the solution containing the main components of commercial polysulfones, the aromatic dihalide sulfone and bisphenol monomers, or to functionalize the related monomers before the condensation. Another approach is to form difunctional polysulfone oligomers. Then, functional groups can be utilized to react with monomers or other polymers to obtain functional polymers or block copolymers. The most applied method is post‐modification of commercially available polysulfones by incorporation of functional groups to their aromatic groups and their use in the formation of graft polymers or polysulfone‐based networks. © 2013 Society of Chemical Industry

Synthesis and Properties of Polymers Containing 2H-Benzimidazol-2-one Moieties: Polymerization via N-C Coupling Reactions.

Novel homopolymers and copolymers containing 2H-benzimidazol-2-one units have been synthesized by N-C coupling reactions of 1H-benzo[d]imidazol-2(3H)-one and activated aromatic dihalides under conditions similar to those for the synthesis of poly(aryl ether)s and poly(benzimidazole sulfone)s. 1H-Benzo[d]imidazol-2(3H)-one behaved like a bisphenol in the polymerization reaction to afford, quantitatively, high molecular weight linear polymers with inherent viscosities (ηinh) ranging from 0.57 to 1.31 dL/g. The polymers were soluble in various organic solvents, and transparent, flexible, and creasable films were cast from its dichloromethane-solution. The homopolymer had a remarkably high glass transition temperature (Tg 348 °C) and good thermal stability. Only 30 mol % (8.9 wt %) of the 2H-benzimidazol-2-one unit for the copolymer with 4,4'-biphenol was required to raise the Tg of commercial poly(aryl ether), Radel R-5000 from 220 to 269 °C.

Synthesis of Cardo Based Poly(arylene ether)s for Flexible Plastic Substrates and Their Properties

New poly(arylene ether)s (PAEs) with both transparency and heat-resistance were prepared by a polycondensation of FBPODS, an ordered-sequence aromatic dihalide, and cardo typed aromatic diols containing fluorene and/or adamantane moiety and also non-cardo typed 1,5-naphthalene diol. The resulting polymers had their glass transition temperatures ranged from 202 to . Based on TGA data, they exhibited excellent thermal stabilities, showing 5% weight loss at . They had low thermal expansion coefficients of 58-59 ppm at temperature range of as well as good mechanical properties with moduli of 1757-2143 MPa. The optical transmittance for the PAE films was over 70% at 550 nm, except for the PAE that contains naphthalene moiety (30% at 550 nm). They also showed water uptake of about 0.68% regardless of their chemical compositions. Therefore, the newly developed PAEs show strong potential as plastic substrates for flexible devices for display, solar cell and e-paper.

Transparency and high heat resistance of cardo based poly(arylene ether)s for flexible plastic substrates

New poly(arylene ether)s (PAEs) with both transparency and heat-resistance were prepared by the polycondensation of 4-fluoro-4′(((fluorobenzoyl)phenyl)-oxy)diphenyl sulfone), an ordered-sequence aromatic dihalide, and cardo typed aromatic diols that contain fluorene, adamantane, or cyclohexane moiety. The resulting polymers were found to be amorphous by X-ray diffraction, and their glass transition temperatures ranged from 194 to 245 °C. Based on the TGA data, they exhibited excellent thermal stability, showing 5% weight loss at 444–496 °C. They had low thermal expansion coefficients of 58–74 ppm at the temperature range of 50–200 °C as well as good mechanical properties with moduli of 1,785–2,350 MPa, except for the PAE that contains the cyclohexane moiety (86 ppm at 50–160 °C; 1,070 MPa). The optical transmittance of the PAE films (ca. 40 μm thick) was more than 70% at 450–800 nm and they also exhibited a very high refractive index in the range of 1.714–1.752 at 589 nm. In addition, their films showed a low water uptake of approximately 0.65% regardless of their chemical composition. Therefore, the newly developed PAEs show strong potential as plastic substrates for flexible devices for displays, solar cells and e-paper.

Synthesis and characterization of organo‐soluble poly(ether ether ketone)s and poly(ether ether ketone ketone)s containing pendant pentadecyl chains

AbstractPoly(ether ether ketone)s and poly(ether ether ketone ketone)s containing pendant pentadecyl chains were synthesized by polycondensation of each of the two bisphenol monomers viz, 1,1,1‐[bis(4‐hydroxyphenyl)‐4′‐pentadecylphenyl]ethane and 1,1‐bis(4‐hydroxyphenyl)‐3‐pentadecyl cyclohexane with activated aromatic dihalides namely, 4,4′‐difluorobenzophenone, and 1,3‐bis(4‐fluorobenzoyl)benzene in a solvent mixture of N,N‐dimethylacetamide and toluene, in the presence of anhydrous potassium carbonate. Polymers were isolated as white fibrous materials with inherent viscosities and number average molecular weights in the range 0.70–1.27 dL g−1 and 76,620–1,36,720, respectively. Poly(ether ether ketone)s and poly(ether ether ketone ketone)s were found to be soluble at room temperature in organic solvents such as chloroform, dichloromethane, tetrahydrofuran, and pyridine and could be cast into tough, transparent, and flexible films from their solutions in chloroform. Wide angle X‐ray diffraction patterns exhibited a broad halo at around 2θ = ∼ 19° indicating that the polymers containing pentadecyl chains were amorphous in nature. In the small‐angle region, diffuse reflections of a typically layered structures resulting from the packing of pentadecyl side chains were observed. The temperature at 10% weight loss, obtained from TG curves, for poly(ether ether ketone)s and poly(ether ether ketone ketone)s were in the range 416–459°C, indicating their good thermal stability. A substantial drop in glass transition temperatures (68–78°C) was observed for poly(ether ether ketone)s and poly(ether ether ketone ketone)s due to “internal plasticization” effect of flexible pendant pentadecyl chains. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Theoretical considerations on the hydrolysis of 2-dichloromethylbenzimidazole

Hydrolysis reaction of 2-dichloromethylbenzimidazole with aqueous diethylamine was studied both experimentally and theoretically. The behavior of two other aromatic dihalides (dibromomethylbenzene and 2-fluoro-dichloromethylbenzene) was also theoretically studied, starting from already known experimental results. The theoretical calculations of local DFT-based descriptors (i.e., Fukui function, electrophilicity index) successfully account for the different reactivity of the three aromatic dihalides in the same hydrolysis reaction. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011

Syntheses and Characterization of Sulfonated Poly(arylene ether sulfone) Containing Naphthyl Moiety as Pendent Groups for Proton Exchange Membranes

Abstract Novel poly(arylene ether sulfone) with sulfonic acid groups attached onto pendent naphthyl rings was successfully synthesized by the nucleophilic displacement of aromatic dihalides with bisphenols in aprotic solvent, followed by sulfonation with chlorosulfonic acid. The sulfonation took place only on the pendent naphthyl rings due to the specially designed molecular structure. The sulfonated polymers are soluble in common organic solvents and can be readily cast into tough and smooth films. The films of the side-chain-type polymer showed good thermal and oxidation stabilities.

Polyrotaxanes based on polyethers and β-cyclodextrin

A polyrotaxane in which β-cyclodextrins (β-CDs) are threaded onto a polyether chain was prepared by polycondensation of a β-CD/bisphenol A (BPA) inclusion complex with aromatic dihalides. Two dihalides, with and without a side chain, were used. This polycondensation results in a polyrotaxane (or pseudopolyrotaxane for polymers without stoppers) with a 1:1 threading ratio when the side chain is present and 2:3 when there is none. The long side chain prevents dethreading of the macrocycles. The best yield and a good threading ratio were obtained when the polycondensation was performed by liquid−solid phase transfer catalysis without solvent (L/S PTC) using 2,5-bi(iodomethyl)-4-methoxy-(1-octyloxy)benzene as dihalide. The 1H NMR and FTIR spectra show that the products consist of β-CD and polyether. The 2D NOESY NMR spectrum shows that the polyether chains are included in the β-CD cavity. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4391–4399, 2009

Synthesis and Characterization of Poly(arylene-ethynylene)s with Ferrocene Unit by Reaction of 1,1'-Bis(ethynyldimethylsilyl)ferrocene and Aromatic Dihalides

the C-C bond forming reactions of 1,1´-bis(ethynyldimethylsilyl)ferrocene and various aromatic dihalides in high yields. The aromatic dihalides include 1,4-dibrom obenzene, 4,4´-dibromobiphenyl, 9,10-dibromoanthracene, 2,5-dibromopyridine, 2,5-dibromothiophene, and 2,6-diiodo- 4-nitroaniline. The polymer structures and properties were characterized by such instrumental methods as NMR (

Highly sulfonated poly(aryl ether ketone) block coplymers having a cross-linking structure

Multi-block copolymers of sulfonated poly(aryl ether ketone) (PAEK) were synthesized by polycondensation of aromatic dihalide, bisphenol and hydroxy-terminated sulfonated oligomer, which was synthesized from sulfonated aromatic dihalide and bisphenol. These sulfonated PAEKs had benzophenone units and methyl moieties in their structure, and they could be cross-linked by UV irradiation. The effects of the multi-block structure were investigated by comparison of the properties of the multi-block copolymer and a random copolymer. The multi-block structure could reduce the methanol permeability efficiency without decreasing the proton conductivity, and it was concluded that the combination of a multi-block structure and a cross-linking system is a useful method for sulfonated PAEKs for the proton-exchange membrane in a DMFC.

Synthesis and characterization of sulfonated poly(arylene thioether)s and their blends with polybenzimidazole for proton exchange membranes

A series of sulfonated poly(arylene thioether)s were successfully prepared via nucleophilic displacement of aromatic dihalides with thiomonomers (4,4′-thiodiphenol or 4,4′-thiobisbenzenethiol) in the presence of excess of potassium carbonate. The synthesized polymers were characterized by NMR spectroscopy, gel permeation chromatography (GPC) and thermogravimetric analysis. Proton exchange membranes were prepared from blends of the sulfonated poly(arylene thioether)s and polybenzimidazole (PBI) and investigated in terms of water uptake and swelling, proton conductivity and oxidative chemical stability. PBI-sulfonated polymer blend membranes had a room temperature proton conductivity in the range 0.12–0.22 S/cm and exhibited lower water uptakes and better chemical stability against hydrogen peroxide treatment as compared to that of pure sulfonated polymer membranes. The membrane prepared from the blend of sulfonated poly(arylene thiosulfone)s and PBI showed excellent oxidative stability, displaying no weight loss for 45 h in 5 wt% hydrogen peroxide solution at 60 °C.

Oxidatively stable and highly proton conductive membrane from poly(arylene ether)s containing biphenyl moiety as pendent groups

Novel poly(arylene ether)s with sulfonic acid groups attached onto pendent biphenyl rings were successfully synthesized by the nucleophilic displacement of aromatic dihalides with bisphenols in aprotic solvent in the present of excess potassium carbonate, followed by sulfonation with chlorosulfonic acid. The sulfonation took place only on the pendent biphenyl rings due to the specially designed molecular structure. The sulfonated polymers were very soluble in common organic solvents, such as dimethyl sulfoxide, N, N′-dimethylacetamide, dimethylformamide, and can be readily cast into tough and smooth films. These membranes showed excellent stabilities resistance to both oxidation and hydrolysis, as evidenced by subjecting to both Fenton's reagent test and immersion in boiling water. The proton conductivities (3.2 × 10 −3 S cm −1) of the as-made membranes were higher than that of Nafion ® 117 (1.9 × 10 −3 S cm −1) under same conditions. The satisfied properties of these new polymers demonstrated them as promising candidates for proton exchange membrane in PEM fuel cell applications.

Synthesis and characterization of poly(arylene ether)s containing triphenylmethane moieties for proton exchange membrane

A series of poly(arylene ether)s containing triphenylmethane moiety were synthesized by the nucleophilic displacement of aromatic dihalides with bisphenols in an aprotic solvent in the presence of excess potassium carbonate. High molecular weight and fibrous polymers in white color can be readily afforded in short reaction time. The structures of the synthesized monomers and polymers were investigated by 1H NMR and MS techniques. The sulfonation position of the synthesized polymer can be easily controlled and the water-up-take can be conveniently tailored by changing the amount of sulfonation agent. This sulfonated polymer 4b is soluble in polar organic solvents, such as NMP, DMAc, DMSO, DMF, ethylene glycol monomethyl ether, and can be readily cast into tough and smooth films from solutions. The sulfonated polymers can be potentially used as the proton-exchange membranes for fuel-cells.

Synthesis and sulfonation of poly(arylene ether)s containing tetraphenyl methane moieties

AbstractNovel poly(arylene ether)s with sulfonic acid containing pendent groups were successfully synthesized by the nucleophilic displacement of aromatic dihalides with bisphenols in an aprotic solvent in the presence of excess potassium carbonate followed by sulfonation with chlorosulfonic acid. The sulfonation took place only at the controlled positions on the phenyl rings due to the novel bisphenol structures designed. The sulfonic acid group containing polymers were very soluble in common organic solvents, such as dimethyl sulfoxide, N,N′‐dimethylacetamide, and dimethylformamide, but swelled only slightly in water. These sulfonic acid group containing polymers were readily cast into tough and smooth films from organic solvents. The synthesized polymers had high glass‐transition temperatures of 171.0–240.7 °C and high molecular weights of 15,600–33,000 Da. These films could potentially be used as proton‐exchange membranes for fuel cells. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1779–1788, 2004