Nitro Displacement Reaction Research Articles

Poly(arylene ether)s with Low Refractive Indices: Poly(biphenylene oxide)s with Trifluoromethyl Pendant Groups via a Meta-Activated Nitro Displacement Reaction

High-molecular-weight poly(biphenylene oxide)s (PBPO) were prepared from AB-type monomers, 4′(3′)-hydroxy-4-nitro-2,6-bis(trifluoromethyl)biphenyl, through a meta-activated nitro displacement reaction. The displacement of nitro leaving group activated by the two trifluoromethyl groups at the meta-position produced high-molecular-weight polymers, which implies that nucleophilic aromatic substitution reaction of the nitro leaving group proceeded very effectively with two activating groups at the meta-position. The obtained polymers have weight-average molecular weight of 20 800–143 300 g/mol and molecular weight distribution of 1.68–2.85. While two homopolymers of 4′- or 3′-hydroxy-4-nitro-2,6-bis(trifluoromethyl)biphenyl, p-PBPO and m-PBPO, showed a semicrystalline morphology, copolymers of the two monomers were amorphous and dissolved in a wide range of organic solvents. The PBPOs possessed a high glass transition temperature (Tg) in the range of 169 to 208 °C depending on their structure and high thermal stability with 10% weight loss temperatures from 486 to 542 °C in nitrogen and from 465 to 516 °C in air. Moreover, PBPOs containing two trifluoromethyl groups showed low refractive indices in the range of 1.4979–1.5052 as well as low birefringence values of 0.0095–0.0148.

Synthesis and characterization of polyetherimides via aromatic nitro displacement reaction

Two ether groups containing bisnitrophthalimide monomers 4,4’-Bis(4-nitrophthalimido phenoxy)diphenyl sulfone and 4,4'-bis (4-nitrophthalimido phenoxy)benzophenone were synthesized. The monomers were characterized by Fourier transform infrared (IR) spectroscopy and 1H-NMR. The polyetherimides were prepared from bisnitrophthalimides by nucleophilic displacement of nitro group by bisphenolate ion. The polyetherimides were characterized by IR, 1H-NMR, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, dielectric constants, solution viscosity and solubility. Polyetherimides were soluble in polar approtic solvents and improved solubility in common organic solvents is due to the presence of flexible groups in the polymer backbone. Polyetherimides exhibited good thermal stability and the temperature at which 10% weight loss occurs in the range 357—453°C in a nitrogen atmosphere. X-ray diffraction measurements revealed that these polyetherimides are amorphous.

Poly(arylene ether)s with trifluoromethyl groups via meta-activated nitro displacement reaction

New poly(arylene ether)s with pendent trifluoromethyl groups were synthesized from 2,2′-bis(trifluoromethyl)-4,4′-dinitro-1,1′-biphenyl with several bisphenols. The nitro leaving group activated by the trifluoromethyl group at meta position was quantitatively displaced with phenolate ions, resulting in high molecular weight polymers. The quantum mechanical calculation of the energy state suggested that the nitro displacement reaction activated by the trifluoromethyl group at meta position is an energetically favorable process. The polymers having weight average molecular weight of 42,100–95,000 g/mol and molecular weight distribution of 2.65–2.95 were obtained. The polymers were amorphous and dissolved in a wide range of organic solvents. Transparent and flexible films were obtained by solution casting. The resulting polymers are thermally stable, and T gs of the polymers are in the range of 176–199 °C depending on their molecular structure. All of the synthesized polymers show refractive indices in the range of 1.592–1.624 with low birefringence below 0.006.

New Sulfonated Polyethers and Polynaphthylimides based on TNT Derivatives

New sulfonated and non-sulfonated monomers — dinitro and diamino compounds — were prepared on the basis of 1,3,5-trinitrobenzene (TNB) which is the demethylation product of 2,4,6-trinitrotoluene (TNT). The sulfonated dinitrocompounds interacted with different binuclear bis-phenols under the conditions of aromatic nucleophilic nitrodisplacement reactions. Polyethers of moderate molecular weights were prepared on the basis of dinitrocompound containing electron-withdrawing 3,5-dinitrodiphenyl sulfone-4′-sulfonic acid “bridging” groups. Copolymers and blends with other sulfonated polymers were prepared to improve the film-forming properties of the polyethers developed on the basis of 3,5-dinitrodiphenyl sulfone-4′-sulfonic acid. High molecular weight sulfonated polynaphthylimides were prepared by the interaction of sulfonated diamine containing electron-donating ether group — 3,5-diaminodiphenyl ether-4′-sulfonic acid — with bis(naphthalic anhydride)s. The sulfonated polyethers and polynaphthylimides thus obtained contain sulfonic acid groups in the side chains.

Novel Polyimide System Based on Nitro Displacement/Diels-Alder Reactions

Poly(ether-imides) were prepared by two simultaneous reactions, that is, Diels-Alder reaction and nitro displacement reaction. Thus 3-nitrophthalic anhydride was reacted with furfuryl amine and the resultant amic acid was then reacted with three bismaleimides (2a–c) and disodium salt of bisphenol–A. The obtained polymers were treated with acetic anhydride to form cyclic imide, as well as aromatization of Diels-Alder adduct. The poly(ether-imide)s were characterized by IR spectral studies and theromgravimetry. A “in situ” polymerization on glass fibers was also carried out and the laminates were characterized by physical, mechanical, and chemical properties.

Synthesis of nitrile and benzoyl substituted poly(biphenylene oxide)s via nitro displacement reaction

A series of substituted poly(biphenylene oxide)s (PBPOs) was synthesized via nucleophilic nitro displacement reactions. High molecular weight PBPO's with nitrile groups were effectively synthesized from the polymerization of A-B type monomers with K2CO3 as a base in N-methyl-2-pyrrolidinone (NMP) at 140°C. The polymers are completely amorphous, soluble in polar aprotic solvents, and formed flexible films on solution casting. Para-linked PBPO with nitrile groups showed excellent thermal properties such as high 5% weight loss temperature above 530°C and Tg at 241°C which is higher than those of commercially available PPO™ (Tg=210°C). The pendent nitrile groups of PBPO were easily transformed to carboxylic acid groups by acidic hydrolysis.

Synthesis of Poly(arylene ether)s Containing Triphenylamine Units via Nitro Displacement Reaction

Synthesis of Poly(arylene ether)s Containing Triphenylamine Units via Nitro Displacement Reaction

Synthesis of Poly(arylene ether amide)s Containing CF3 Groups by Nitro Displacement Reaction of AB-Type Monomers

New poly(arylene ether amide)s with trifluoromethyl pendent groups were prepared via nucleophilic nitro displacement reaction of AB-type monomers. 4-Nitro-3-trifluoromethyl-[N-(4-hydroxyphenyl)]benzamide (3) and 4-nitro-3-trifluoro-methyl-[N-(3-hydroxyphenyl)]benzamide (4) gave polymers with weight-average molecular weights over 42 000 g/mol and glass transition temperatures of 269°C and 213°C, respectively. Both polymers were soluble in common organic solvents including THF, and formed transparent films upon casting.

Poly(arylene ether)s via Nitro Displacement Reaction: Synthesis of Poly(biphenylene oxide)s Containing Trifluoromethyl Groups from AB Type Monomers

Poly(arylene ether)s via Nitro Displacement Reaction: Synthesis of Poly(biphenylene oxide)s Containing Trifluoromethyl Groups from AB Type Monomers

Synthesis and properties of poly(ether imide)s based on the bis(ether anhydride)s from hydroquinone and its derivatives

Four bis(ether anhydride)s, 4,4'-(1,4-phenylenedioxy)diphthalic anhydride (IV), 4,4'-(2,5-tolylenedioxy)-diphthalic anhydride (Me-IV), 4,4'-(2-chloro-1,4-phenylenedioxy)diphthalic anhydride (Cl-IV), and 4,4'-(2,5-biphenylenedioxy)diphthalic anhydride (Ph-IV), were prepared in three steps starting from the nucleophilic nitro-displacement reaction of 4-nitrophthalonitrile with the potassium phenoxides of hydroquinone and various substituted hydroquinones such as methylhydroquinone, chlorohydroquinone, and phenylhydroquinone in N,N-dimethylformamide, followed by alkaline hydrolysis and dehydration. Four series of poly(ether imide)s were prepared from bis(ether anhydride)s with various aromatic diamines by a classical two-step procedure. The inherent viscosities of the intermediate poly(amic acid)s were in the range of 0.40-2.63 dL/g. Except for those derived from p-phenylenediamine and benzidine, almost all the poly(amic acid)s could be solution-cast and thermally converted into transparent, flexible, and tough polyimide films. Introduction of the chloro or phenyl substituent leads to a decreased crystallinity and an increased solubility of the polymers. The glass transition temperatures (T g ) of these polyimides were recorded in the range of 204-263°C. In general, the methyl- and chloro-substituted polyimides exhibited relatively higher T g s, whereas the phenyl-substituted ones exhibited slightly lower T g s compared to the corresponding nonsubstituted ones. Thermogravimetric analysis (TG) showed that 10% weight loss temperatures of all the polymers were above 500°C either in nitrogen or in air.

Simple synthetic route to soluble polyimides via nitro‐displacement reaction and their second‐order nonlinear optical properties

Y. Lee, H. Young Woo, C. Yoon and H. Shim, J. Mater. Chem., 1999, 9, 2345 DOI: 10.1039/A902230I

Synthesis of poly(arylene ether ketone)s containing amide side groups via nitro displacement reaction

Synthesis of poly(arylene ether ketone)s containing amide side groups via nitro displacement reaction

Synthesis of poly(arylene ether ketone)s containing amide side groupsvia nitro displacement reaction

New amorphous poly(arylene ether ketone)s with amide substituents were prepared via nucleophilic nitro displacement reaction. The dinitro monomer, 1,4-bis[4-nitro-3-(1-piperidylcarbonyl)benzoyl]benzene, was synthesized through a masked acyl anion equivalent, bis(aminoacetonitrile). The weight average molecular weight (M W ) of the polymers is about 40 000. the glass transition temperature around 200 C. The polymers are soluble in common organic solvents such as chloroform, 1,1,2-trichloroethane, and N-methyl-2-pyrrolidone (NMP). The polymer from the dinitro monomer and bisphenol A is easily cast into a transparent and flexible freestanding film. 5% weight loss temperatures of the polymers are in the range from 409-418 C under N 2 .

Synthesis and properties of poly(ether imide)s derived from 2,6-bis(3,4-dicarboxyphenoxy)naphthalene dianhydride and aromatic diamines

A new naphthalene unit-containing bis(ether anhydride), 2,6-bis(3,4-di- carboxyphenoxy)naphthalene dianhydride, was synthesized in three steps starting from the nucleophilic nitrodisplacement reaction of 2,6-dihydroxynaphthalene and 4- nitrophthalonitrile in N,N-dimethylformamide (DMF) solution in the presence of potas- sium carbonate, followed by alkaline hydrolysis of the intermediate bis(ether dinitrile) and subsequent dehydration of the resulting bis(ether diacid). High-molar-mass aro- matic poly(ether imide)s were prepared using a conventional two-step polymerization process from the bis(ether anhydride) and various aromatic diamines. The intermedi- ate poly(ether amic acid)s had inherent viscosities of 0.65-2.03 dL/g. The films of poly(ether imide)s derived from two rigid diamines, i.e. p-phenylenediamine and benzi- dine, crystallized during the thermal imidization process. The other poly(ether imide)s belonged to amorphous materials and could be fabricated into transparent, flexible, and tough films. These aromatic poly(ether imide) films had yield strengths of 104- 131 MPa, tensile strengths of 102-153 MPa, elongation to break of 8-87%, and initial moduli of 1.6-3.2 GPa. The glass transition temperatures (Tg's) of poly(ether imide)s were recorded in the range of 220-2777C depending on the nature of the diamine moiety. All polymers were stable up to 5007C, with 10% weight loss being recorded above 5507C in both air and nitrogen atmospheres. q 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1657-1665, 1998

Synthesis and characterization of aromatic poly(ether sulfone imide)s derived from sulfonyl bis(ether anhydride)s and aromatic diamines

Two sulfonyl group-containing bis(ether anhydride)s, 4,4′-[sulfonylbis(1,4-phenylene)dioxy]diphthalic anhydride (IV) and 4,4′-[sulfonylbis(2,6-dimethyl-1,4-phenylene)dioxy]diphthalic anhydride (Me-IV), were prepared in three steps starting from the nucleophilic nitrodisplacement reaction of the bisphenolate ions of 4,4′-sulfonyldiphenol and 4,4′-sulfonylbis(2,6-dimethylphenol) with 4-nitrophthalonitrile in N,N-dimethylformamide (DMF). High-molar-mass aromatic poly(ether sulfone imide)s were synthesized via a conventional two-stage procedure from the bis(ether anhydride)s and various aromatic diamines. The inherent viscosities of the intermediate poly(ether sulfone amic acid)s were in the ranges of 0.30–0.47 dL/g for those from IV and 0.64–1.34 dL/g for those from Me-IV. After thermal imidization, the resulting two series of poly(ether sulfone imide)s had inherent viscosities of 0.25–0.49 and 0.39–1.19 dL/g, respectively. Most of the polyimides showed distinct glass transitions on their differential scanning calorimetry (DSC) curves, and their glass transition temperatures (Tg) were recorded between 223–253 and 252–288°C, respectively. The results of thermogravimetry (TG) revealed that all the poly(ether sulfone imide)s showed no significant weight loss before 400°C. The methyl-substituted polymers showed higher Tg's but lower initial decomposition temperatures and less solubility compared to the corresponding unsubstituted polymers. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1649–1656, 1998

Synthesis of Poly(arylene ether ketone)s Containing Trifluoromethyl Groups via Nitro Displacement Reaction

Synthesis of Poly(arylene ether ketone)s Containing Trifluoromethyl Groups via Nitro Displacement Reaction

Synthesis and properties of poly(ether imide)s derived from 2,7-bis(3,4-dicarboxyphenoxy)naphthalene dianhydride and various aromatic diamines

A naphthalene unit-containing bis(ether anhydride), 2,7-bis(3,4-dicarboxyphenoxy)naphthalene dianhydride, was prepared in three steps starting from the nucleophilic nitrodisplacement reaction of 2,7-dihydroxynaphthalene and 4-nitrophthalonitrile in N,N-dimethylformamide (DMF) solution in the presence of potassium carbonate followed by alkaline hydrolysis of the intermediate bis(ether dinitrile) and subsequent dehydration of the resulting bis(ether diacid). High-molar-mass aromatic poly(ether imide)s were synthesized using a conventional two-stage polymerization process from the bis(ether anhydride) and ten aromatic diamines. The intermediate poly(ether amic acid)s had inherent viscosities of 0.95–2.67 dL/g. The films of poly(ether imide)s derived from two rigid diamines, that is, p-phenylenediamine and benzidine, crystallized and embrittled during the thermal imidization process. The other poly(ether imide)s belonged to amorphous materials and could be fabricated into transparent, flexible, and tough films. These poly(ether imide) films had yield strengths of 91–115 MPa, tensile strengths of 89–136 MPa, elongation to break of 11–45%, and initial moduli of 1.7–2.2 GPa. The Tgs of poly(ether imide)s were recorded in the range of 222–256°C depending on the nature of the diamine moiety. All polymers were thermally stable up to 500°C, with 10% weight loss being recorded above 540°C in air and nitrogen atmospheres. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2281–2287, 1997

Synthesis and characterization of polyimides based on isopropylidene-containing bis(ether anhydride)s

Two bis(ether anhydride)s, 4,4′-[1,4-phenylenebis(isopropylidene-1,4-phenyleneoxy)]-diphthalic anhydride (IVa) and 4,4′-[isopropylidenebis(1,4-phenylene)dioxy]diphthalic anhydride (IVb), were prepared in three steps starting from the nucleophilic nitrodisplacement reaction of 4-nitrophthalonitrile with α,α ′-bis(4-hydroxyphenyl)-1,4-diisopropylbenzene (Ia) and 4,4′-isopropylidenediphenol (Ib) in N,N-dimethylformamide (DMF) in the presence of potassium carbonate. The bis(ether anhydride)s IVa and IVb were polymerized with various aromatic diamines to obtain two series of poly(ether amic acid)s VIa–g and VIIa–g with inherent viscosities in the range of 0.30∼0.74 and 0.29∼1.01 dL/g, respectively. The poly(ether amic acid)s were converted to poly(ether imide)s VIIIa–g and IXa–g by thermal cyclodehydration. Most of the poly(ether imide)s could afford flexible and tough films, and they showed high solubility in polar solvents such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide, and m-cresol. The obtained poly(ether imide) films had tensile strengths of 45∼83 MPa, elongations-to-break of 6∼27%, and initial modulus of 0.6∼1.7 GPa. The Tgs of poly(ether imide)s VIIIa–g and IXa–g were in the range of 194∼210 and 204∼243 °C, respectively. Thermogravimetric analysis (TG) showed that 10% weight loss temperatures of all the polymers were above 500 °C in both air and nitrogen atomspheres.

New aryloxy-substituted condensation polymers

Large family of new aromatic diamines containing aryloxy side groups was developed. All the diamines were obtained on the basis of 2,4,6-trinitrotoluene (TNT) — very cheap and available explosive material. TNT was converted into 1,3,5-trinitrobenzene (TNB); subsequent aromatic nucleophilic nitro-displacement reactions led to mono- and diaryloxy-substituted mono- and dinitrobenzenes which were converted into the final aryloxy-substituted diamines. Interaction of the diamines obtained with aromatic dicarboxylic acids chlorides and aromatic tetracarboxylic acids dianhydrides led to the formation of new aryloxy-substituted polyimides and polyimides combining high thermal properties with solubility in organic solvents.

Nitrodisplacement reactions and the synthesis of bis (ether anhydride) s from dihydroxynaphthalenes

Nitrodisplacement reactions between all ten dihydroxynaphthalenes and 4-nitrophthalodinitrile have been studied. Apart from 1,8-dihydroxynaphthalene, all dihydroxynaphthalenes undergo nitrodisplacement but only 1,5-, 2,3-, 2,6- and 2,7-dihydroxynaphthalenes give high yields of pure bis(ether dinitrile). The bisfether dinitrile's produced in high yield were hydrolysed and converted to bis(ether anhydride) for subsequent synthesis of poly(ether imide)s. Success in nitrodisplacement correlates with high redox potentials for the dihydroxynaphthalenes, except for 1,8-dihydroxynaphthalene which probably fails to react because of steric constraints at the peri positions.