Alkylation of phenol with olefins in the presence of catalysts based on mesoporous aromatic frameworks

Mesoporous polyaromatic frameworks (PAFs) based on tetraphenylmethane were obtained and modified with sulfonic acid groups. The compounds were characterized by solid-state ¹³C NMR and IR spectroscopy, low-temperature nitrogen adsorption-desorption, and transmission electron microscopy. The acidities of the PAF-1-SO₃H and PAF-2-SO₃H samples determined by titration were 3.99 mmol g^–1 and 0.91 mmol g^–1, respectively. The catalytic activity of PAF-SO₃H for alkylation of phenol with linear terminal olefins was investigated. The reaction products were isomeric monoalkylphenols (C-alkylates), and alkyl phenyl ethers (O-alkylates).     

STUDY ON THE EFFECT OF POLYSTYRENE SULFONIC ACID MACROMOLECULES ON THE POLYMERIZATION OF ACRYLAMIDE

The effect of polystyrene sulfonic acid (PSSA) macromolecules on the polymerization of acrylamide (AM) has been studied. It was found that the rates of polymerization of AM were greatly increased in the presence of PSSA in the polymerization system.The maximum value of the rate of polymerization of AM was obtained when the ratio of [—SO_3H]: [AM] reached 3:1. When the insoluble crosslinked PSSA was used instead of the soluble one, this effect decreased considerably. The interaction between molecules of PSSA and AM was determined by infrared spectroscopy, elementary analysis and X-ray photoelectron spectroscopy. The combination form, —SO_3-NH_3~ CO—, formed between sulfonic group and amide group was found to be existed since the infrared absorption band of —NH_2 shifted from 3400cm~(-1) to 3150 cm~(-1), the binding energy of electron N_(18) changed from 399.7 eV to 401.3 eV, and the atomic ratio of N to S of the products was similar to the ratio of reagents. Based on these experimental results, the mechanism of AM polymerization in the presence of PSSA is proposed. The initial step is the combination of AM with sulfonic group to form —CONH_3~ , then followed by polymerization on the PSSA macromolecule. The role of PSSA on the polymerization of AM is discussed.     

Preparation and characterization of anion‐exchange membranes derived from poly(vinylbenzyl chloride‐co‐styrene) and intercalated montmorillonite

In this paper, three organic intercalating agents containing cations [hexadecyl trimethyl ammonium bromide (CTAB), poly(acrylamide‐co‐diallyldimethylammonium chloride), and quaternized polyethyleneimine] are used to prepare intercalated montmorillonites (MMT) by ion‐exchange method. Then the modified MMTs are doped with vinylbenzyl chloride and styrene copolymer [poly(vinylbenzyl chloride‐co‐styrene)] for fabricating composite anion‐exchange membranes (AEM). Fourier transform infrared, X‐raydiffraction, thermogravimetric analysis, scanning electron microscopy, and Mastersizer laser particle size analyzer are employed to characterize the structure and morphology of MMTs and AEMs. The successful intercalation of MMTs is approved, and the MMT intercalated by CTAB shows an interlayer distance of 2.31 nm. The properties of the composite membranes including water uptake, mechanical property, and ionic conductivity are investigated. Among all the AEMs, the composite membrane containing MMT sheets with CTAB demonstrates better compositive performances. It presents an ionic conductivity of 2.09 × 10^?2 S cm^?1 at 80°C and good alkaline solution stability. Copyright © 2016 John Wiley & Sons, Ltd.     

Proton conducting membranes based on poly(vinyl chloride) graft copolymer electrolytes

The direct preparation of proton conducting poly(vinyl chloride) (PVC) graft copolymer electrolyte membranes using atom transfer radical polymerization (ATRP) is demonstrated. Here, direct initiation of the secondary chlorines of PVC facilitates grafting of a sulfonated monomer. A series of proton conducting graft copolymer electrolyte membranes, i.e. poly(vinyl chloride)‐g‐poly(styrene sulfonic acid) (PVC‐g‐PSSA) were prepared by ATRP using direct initiation of the secondary chlorines of PVC. The successful syntheses of graft copolymers were confirmed by ¹H‐NMR and FT‐IR spectroscopy. The images of transmission electron microscopy (TEM) presented the well‐defined microphase‐separated structure of the graft copolymer electrolyte membranes. All the properties of ion exchange capacity (IEC), water uptake, and proton conductivity for the membranes continuously increased with increasing PSSA contents. The characterization of the membranes by thermal gravimetric analysis (TGA) also demonstrated their high thermal stability up to 200°C. The membranes were further crosslinked using UV irradiation after converting chlorine atoms to azide groups, as revealed by FT‐IR spectroscopy. After crosslinking, water uptake significantly decreased from 207% to 84% and the tensile strength increased from 45.2 to 71.5 MPa with a marginal change of proton conductivity from 0.093 to 0.083 S cm^?1, which indicates that the crosslinked PVC‐g‐PSSA membranes are promising candidates for proton conducting materials for fuel cell applications. Copyright © 2008 John Wiley & Sons, Ltd.     

Superprotonic Conductivity of a UiO‐66 Framework Functionalized with Sulfonic Acid Groups by Facile Postsynthetic Oxidation

Facile postsynthetic oxidation of the thiol‐laced UiO‐66‐type framework UiO‐66(SH)₂ enabled the generation of UiO‐66(SO₃H)₂ with sulfonic acid groups covalently linked to the backbone of the system. The oxidized material exhibited a superprotonic conductivity of 8.4×10^?2 S cm^?1 at 80 °C and 90 % relative humidity, and long‐term stability of the conductivity was observed. This level of conductivity exceeds that of any proton‐conducting MOF reported to date and is equivalent to the conductivity of the most effective known electrolyte, Nafion.     

Optimal method for preparing sulfonated polyaryletherketones with high ion exchange capacity by acid-catalyzed crosslinking for proton exchange membrane fuel cells

Sulfonated polyaryletherketones (SPAEK) bearing four sulfonic acid groups on the phenyl side groups were synthesized. The benzophenone moiety of polymer backbone was further reduced to benzydrol group with sodium borohydride. The membranes were crosslinked by acid-catalyzed Friedel-Crafts reaction without sacrifice of sulfonic acid groups and ion exchange capacity (IEC) values. Crosslinked membranes with the same IEC value but different water uptake could be prepared. The optimal crosslinking condition was investigated to achieve lower water uptake, better chemical stability (Fenton's test), and higher proton conductivity. In addition, the hydrophilic ionic channels from originally course and disordered could be modified to be narrow and continuous by this crosslinking method. The crosslinked membranes, CS4PH-40-PEKOH (IEC = 2.4 meq./g), reduced water uptake from 200 to 88% and the weight loss was reduced from 11 to 5% during the Fenton test compared to uncrosslinked one (S4PH-40-PEK). The membrane showed comparable proton conductivity (0.01–0.19 S/cm) to Nafion 212 at 80°C from low to high relative humidity (RH). Single H₂/O₂ fuel cell based on the crosslinked SPAEK with catalyst loading of 0.25 mg/cm² (Pd/C) exhibited a peak power density of 220.3 mW/cm², which was close to that of Nafion 212 (214.0 mW/cm²) at 80°C under 53% RH. These membranes provide a good option as proton exchange membrane with high ion exchange capacity for fuel cells.     

Lithium chloride sorption by zinc hexacyanoferrate(II) from a nonaqueous medium

Mechanisms of lithium chloride sorption by zinc hexacyanoferrate(II) Zn₂Fe(CN)₆ · 2.5H₂O in a nonaqueous medium (ethanol) were studied by chemical analysis, X-ray powder diffraction, wide-line ⁷Li and ¹H NMR, vibrational spectroscopy, and impedance spectroscopy. The physicochemical properties of sorption products are reported. Lithium ions in the sorption products were found to be in a hydrated form. The accommodation of molecularly sorbed Li⁺ aq · Cl^? ion pairs in the bores of channels in the crystal structure results in the formation of a continuous network of hydrogen bonds and changes the proton transport mechanism. As the lithium chloride concentration increases in the temperature range 22–150°C, the conductivity (σ) of sorption products increases three to four orders of magnitude to reach 10^?3 S cm^?1.     

Ion conductive characteristics of DNA containing PEO chains covalently bound on nucleic acid bases

In order to prepare flexible and ion conductive deoxyribonucleic acid (DNA) films without phase separation, DNA was modified with poly(ethylene oxide) (PEO). PEOs with molecular weight of 150 to 2000 were fixed to the amino groups of nucleic acid bases in DNA (PEO‐DNA). Brittle DNA films turned flexible after PEO modification, and the highest ionic conductivity was obtained when PEO with molecular weight of 1000 was modified. Though Na⁺, counter cation of phosphate group, was expected to migrate in these PEO_x‐DNA hybrids as a carrier ion, ionic conductivity was only 1.3 × 10^?6 S cm^?1. Addition of salts to PEO₁₀₀₀‐DNA considerably improved the ionic conductivity, and sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) was the best salt for this purpose. When NaTFSI, 5 mol% to the oxyethylene (OE) unit, was mixed with PEO₁₀₀₀‐DNA, the highest ionic conductivity of 1.77 × 10^?5 S cm^?1 was observed at 30°C. Copyright © 2004 John Wiley & Sons, Ltd.     

Sulfonated polybenzimidazoles: Proton conduction and acid–base crosslinking

A series of soluble, benzimidazole‐based polymers containing sulfonic acid groups (SuPBI) has been synthesized. SuPBI membranes resist extensive swelling in water but are poor proton conductors. When blended with high ion exchange capacity (IEC) sulfonated poly(ether ether ketone) (SPEEK), a polymer that has high proton conductivity but poor mechanical integrity, ionic crosslinks form reducing the extent of swelling. The effect of sulfonation of PBI on crosslinking in these blends was gauged through comparison with nonsulfonated analogs. Sulfonic acid groups present in SuPBI compensate for acid groups involved in crosslinking, thereby increasing IEC and proton conductivity of the membrane. When water uptake and proton conductivity were compared to the IEC of blends containing either sulfonated or nonsulfonated PBI, no noticeable distinction between PBI types could be made. Comparisons were also made between these blends and pure SPEEK membranes of similar IEC. Blend membranes exhibit slightly lower maximum proton conductivity than pure SPEEK membranes (60 vs. 75 mS cm^?1) but had significantly enhanced dimensional stability upon immersion in water, especially at elevated temperature (80 °C). Elevated temperature measurements in humid environments show increased proton conductivity of the SuPBI membranes when compared with SPEEK‐only membranes of similar IEC (c.f. 55 for the blend vs. 42 mS cm^?1 for SPEEK at 80 °C, 90% relative humidity). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3640–3650, 2010     

Correlation between the structural,electrical and electrochemical performance of layered Li(Ni<Subscript>0.33</Subscript>Co<Subscript>0.33</Subscript>Mn<Subscript>0.33</Subscript>)O<Subscript>2</Subscript> for lithium ion battery

The Li(Ni_0.33Co_0.33Mn_0.33)O₂ (LNCMO) cathode material is prepared by poly(vinyl pyrrolidone) (PVP)-assisted sol-gel/hydrothermal and poly(ethylene glycol)-block-poly(propylene glycol)-block-poly (ethylene glycol) (Pluronic-P123)-assisted hydrothermal methods. The compound prepared by PVP-assisted hydrothermal method shows a comparatively higher electrical conductivity of ~2?×?10^?5 S cm^?1 and exhibits a discharge capacity of 152 mAh g^?1 in the voltage range of 2.5 to 4.4 V, for a C-rate of 0.2 C, whereas the compounds prepared by P123-assisted hydrothermal method and PVP-assisted sol-gel method show a total electrical conductivity in the order of 10^?6 S cm^?1 and result in poor electrochemical performance. The structural and electrical properties of LNCMO (active material) and its electrochemical performance are correlated. The difference in percentage of ionic and electronic conductivity contribution to the total electrical conductivity is compared by transference number studies. The cation disorder is found to be the limiting factor for the lithium ion diffusion as determined from ionic conductivity values.     

Guest‐Assisted Proton Conduction in the Sulfonic Mesoporous MIL‐101 MOF

Post‐synthesis modification of MIL‐101(Cr)‐NO₂ was explored in order to decorate the organic backbone by propyl‐sulfonic groups, with the aim to incorporate mobile and acidic protons for solid‐state proton electrolyte applications. The resulting solid switched from insulating towards proton superconductive behavior under humidity, while the conductivity recorded at 363 K and 95 % relative humidity reached 4.8×10^?3 S cm^?1. Propitiously, the impregnation of the material by strong acidic molecules (H₂SO₄) further boosted the proton conductivity performances up to the remarkable σ value of 1.3×10^?1 S cm^?1 at 363 K/95 % RH, which reaches the performances of the best proton conductive MOF reported so far.     

Highly Effective Proton-Conduction Matrix-Mixed Membrane Derived from an -SO3H Functionalized Polyamide

Developing a low-cost and effective proton-conductive electrolyte to meet the requirements of the large-scale manufacturing of proton exchange membrane (PEM) fuel cells is of great significance in progressing towards the upcoming “hydrogen economy” society. Herein, utilizing the one-pot acylation polymeric combination of acyl chloride and amine precursors, a polyamide with in-built -SO₃H moieties (PA-PhSO₃H) was facilely synthesized. Characterization shows that it possesses a porous feature and a high stability at the practical operating conditions of PEM fuel cells. Investigations of electrochemical impedance spectroscopy (EIS) measurements revealed that the fabricated PA-PhSO₃H displays a proton conductivity of up to 8.85 × 10⁻² S·cm⁻¹ at 353 K under 98% relative humidity (RH), which is more than two orders of magnitude higher than that of its -SO₃H-free analogue, PA-Ph (6.30 × 10⁻⁴ S·cm⁻¹), under the same conditions. Therefore, matrix-mixed membranes were fabricated by mixing with polyacrylonitrile (PAN) in different ratios, and the EIS analyses revealed that its proton conductivity can reach up to 4.90 × 10⁻² S·cm⁻¹ at 353 K and a 98% relative humidity (RH) when the weight ratio of PA-PhSO₃H:PAN is 3:1 (labeled as PA-PhSO₃H-PAN (3:1)), the value of which is even comparable with those of commercial-available electrolytes being used in PEM fuel cells. Additionally, continuous tests showed that PA-PhSO₃H-PAN (3:1) possesses a long-life reusability. This work demonstrates, using the simple acylation reaction with the sulfonated module as precursor, that low-cost and highly effective proton-conductive electrolytes for PEM fuel cells can be facilely achieved.     

Multiblock poly(Phenylene ether nitrile)s with pendant sulfoalkoxyl side chain for H2/air fuel cells at low humidity condition

A series of multiblock poly(phenylene ether nitrile)s with pendant sulfoalkoxyl side chains have been developed as proton exchange membranes for fuel cells. The membranes were obtained by a solution casting method and exhibited good thermal stability, flexibility, and mechanical strength. The membranes displayed well‐developed microphase separation, which largely contributed to their excellent ion conduction ability. One of the new membranes with a low ion exchange capacity of 1.57 mequiv g^?1 showed higher proton conductivity than Nafion 212 over the entire RH range (30–95%). The maximum power output generated in a single cell test reached up to 0.754, 0.640, and 0.414 W cm^?2 at 70 °C under 80%, 50%, and 30% RH conditions, respectively. The current density of the membrane obtained at 0.6 V (I _0.6) was as high as 640 mA cm^?2, which was much higher than that of Nafion 212 (375 mA cm^?2 at 30% RH), suggesting its superiority for a more rapid system start‐up. Furthermore, the in situ durability test at 50% RH was performed at a constant current loading, and the membrane did not show any significant voltage reduction over the 400 h testing period. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1940–1948     

Sulfonic and Phosphonic Acid and Bifunctional Organic–Inorganic Hybrid Membranes and Their Proton Conduction Properties

Hybrid organic–inorganic approaches are used for the synthesis of bifunctional proton exchange membrane fuel cell (PEMFC) membranes owing to their ability to combine the properties of a functionalized inorganic network and an organic thermostable polymer. We report the synthesis of both sulfonic and phosphonic acid functionalized mesostructured silica networks into a poly(vinylidenefluoride‐co‐hexafluoropropylene) (poly(VDF‐co‐HFP) copolymer. These membranes, containing different amounts of phosphonic acid and sulfonic acid groups, have been characterized using FTIR and NMR spectroscopy, SA‐XRD, SAXS, and electrochemical techniques. The proton conductivity of the bifunctional hybrid membranes depends strongly on hydration, increasing by two orders of magnitude over the relative humidity (RH) range of 20 to 100 %, up to a maximum of 0.031 S cm⁻¹ at 60 °C and 100 % RH. This value is interesting as only half of the membrane conducts protons. This approach allows the synthesis of a porous SiO₂ network with two different functions, having  SO₃H and  PO₃H₂ embedded in a thermostable polymer matrix.     

Fluoride‐ion‐conducting Polymers: Ionic Conductivity and Fluoride Ion Diffusion Coefficient in Quaternized Polysulfones

We describe the three‐step synthesis of a new polymeric fluoride ion conductor based on the fully aromatic polymer polysulfone (PSU). In the first step, PSU is chloromethylated (CM‐PSU) using reagents (i.e., stannic chloride, paraformaldehyde, and trimethylchlorosilane) that are less toxic than those used in the standard procedure. In the second step, CM‐PSU reacts with a tertiary amine (trimethylamine or 1,4‐diazabicyclo[2.2.2]octane) to form quaternary ammonium groups fixed on the PSU backbone and mobile chloride counter‐anions. The chloride ions can, in a third step, be exchanged with fluoride ions by immersion of the ionomer in NaF solution. The fluoride ion conductivity reaches 3–5 mS cm^?1 at 25 °C and 5–10 mS cm^?1 at 40 °C. We determined the F^? diffusion coefficient in these ionomers by pulsed gradient spin‐echo (PGSE) high‐resolution magic angle spinning (HRMAS) nuclear magnetic resonance (NMR) spectroscopy and by impedance spectroscopy using the Nernst–Einstein relation. The diffusion coefficients determined by the two methods are in good agreement, ranging from 2 to 4×10^?10 m² s^?1. The porosity and tortuosity of the ionomer membranes can be estimated.     

Novel preparation of electrically conducting poly (vinyl chloride) by photo-dehydrochlorination from poly (vinyl chloride)/polypyrrole composite film

Polypyrrole (PPy) was deposited electrochemically on a platinum plate from a nitric acid solution of pyrrole. The PVC/PPy composite film was finally obtained by casting poly(vinyl chloride) (PVC) onto the PPy electrode from a tetrahydrofuran solution of PVC. The prepared composite film was irradiated at 90°C with a low-pressure mercury lamp in the stream of hydrogen gas saturated with steam, and the PVC film was dehydrochlorinated, leading to the formation of conjugated polyene. The electrical conductivity (σ) of the PVC film in the irradiated composite film was reveled: σ=2.51 × 10^?5S cm^?1. By iodine doping, σ was further enhanced up to 5.04 X 10^?3 S cm^?1. The tensile strength of the irradiated composite film became larger than that of the original PVC film; i.e., the stress at break was: 461 (composite film); 401 kg cm^?2 (PVC). These results were brought about by the doping of radical species to the conjugated polyene. The anion, NO^?₃, doped during the electrodeposition of PPy was photodecomposed to generate radical NO₂ and this species was doped to the polyene, resulting in the formation of electrically conductive PVC and mechanically improved composite film. © 1994 John Wiley & Sons, Inc.     

Composite polymer electrolyte membranes comprising triblock copolymer and heteropolyacid for fuel cell applications

Hybrid organic/inorganic composite polymer electrolyte membranes consisting of a triblock copolymer (tBC) and varying concentrations of heteropolyacid (HPA) were investigated for application in proton exchange membrane fuel cells (PEMFC). An ABC triblock copolymer, that is, polystyrene‐b‐poly(hydroxyethyl acrylate)‐b‐poly (styrene sulfonic acid), PS‐b‐PHEA‐b‐PSSA, at 28:21:51 wt % was synthesized via atom transfer radical polymerization (ATRP) and solution‐blended with a commercial HPA. Upon the incorporation of HPA into the tBC, the symmetric stretching bands of both the SO group (1187 cm^?1) and the ? OH group (3440 cm^?1) shifted to lower wavenumbers (1158 and 3370 cm^?1). The shift in these FTIR absorptions suggest that the HPA particles strongly interact with both the sulfonic acid groups in the PSSA domains and the hydroxyl groups in the PHEA domains. When the weight fraction of HPA was increased to 0.2, the room‐temperature proton conductivity of the composite membrane increased from 0.048 to 0.065 S/cm, presumably because of the intrinsic conductivity of the HPA particles and the enhanced acidity of the sulfonic acid in the tBC. The water uptake of the composite membranes decreased from 130 to 48% with an increase of the HPA weight fraction to 0.4. The decrease in water uptake is likely a result of the decrease in the number of available water absorption sites because of the hydrogen bonding interaction between the HPA particles and the tBC matrix. Scanning electron microscopy and transmission electron microscopy images showed that the HPA nanoparticles with a diameter of 200–300 nm were uniformly distributed throughout the tBC matrix up to an HPA weight fraction of 0.4. Thermal stability of the composite membranes (decomposition temperature > 400 °C) was enhanced as compared with the pristine tBC membrane, presumably because of the strong specific interaction of the HPA particles with the sulfonic acid and hydroxyl groups. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 691–701, 2008     

Sulfonic acid pyridinium chloride-functionalized nanoparticles (MnCoFe2O4@Niacin-SO3H)+Cl− as a novel and reusable catalyst for synthesis of tetrahydrodipyrazolopyridines and pyranopyrazoles

The novel pyridinium chloride-functionalized MnCoFe₂O₄-SO₃H nanoparticles, (MnCoFe₂O₄@Niacin-SO₃H)⁺Cl^?, were synthesized by coating the sulfonic group on the surface of MnCoFe₂O₄@Niacin. The activity of these nanoparticles was studied for the synthesis of tetrahydrodipyrazolopyridines and pyranopyrazole derivatives via the multi-component reactions of ethyl acetate, hydrazine, aldehydes, and ammonium acetate or malononitrile. The use of green solvent, easy separation of the catalyst from the reaction medium, easy deposition, high purity, and openness of products are some advantages of this procedure.

     

Preparation of solid alkaline fuel cell binders based on fluorinated poly(diallyldimethylammonium chloride)s [poly(DADMAC)] or poly(chlorotrifluoroethylene‐co‐DADMAC) copolymers

A membrane or an electrode binder to be used in a solid alkaline fuel cell (SAFC) needs to (i) be insoluble in both aqueous solutions and the required fuels, and (ii) exhibit an hydroxide ion conductivity. To achieve these goals, two pathways were employed: (i) one consists of the radical copolymerization of diallyldimethylammonium chloride (DADMAC) with chlorotrifluoroethylene (CTFE) while (ii) the other one is based on the counter‐ion exchange of a poly(DADMAC) by fluorinated anions. First, the radical copolymerization of CTFE with DADMAC under various experimental conditions was achieved in yields up to 85%, and DADMAC percentages in the copolymers were higher than those in the feed compositions. To obtain insoluble copolymers, high CTFE feed contents (>70 mol %) were required. The other route consisting in the partial replacement of the Cl^? counter‐ions in the water‐soluble poly(DADMAC) by bistrifluoromethanesulfonimide (TFSI^?) did confer the starting material insolubility in water while maintaining its conductivity. When the fluorinated poly(DADMAC) was obtained from concentrated solutions of fluorinated surfactant, it was observed that the amount of counter‐ions exchanged was difficult to control, which limits optimization. Nevertheless, under diluted conditions, membranes with ion exchange capacity up to 0.7 meq g^?1, and conductivities close to 1 mS cm^?1 were obtained. Although their conductivities were low, these membranes fulfill the requirements for a SAFC membrane in terms of solubility in DMSO, water insolubility, and thermal stability (T_d,10% > 320 °C). When used in a fuel cell, as a binder in the membrane‐electrode assembly (MEA), significant improvements were noted (+50% of the open circuit voltage, +580% in current density, and +540% in accessible power). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2043–2058, 2009     

Preparation and properties of polymers with biphenyl units in the chain: Syntheses of solvent-soluble substituted polyphenylenes

Benzidinetetrazonium chloride (BTC)–CuCl and BTC–FeCl₂ complexes were thermally converted to benzene-soluble poly-4,4′-biphenylene plus small amounts of insoluble material. The soluble fraction was more stable than the insoluble fraction when heated at 300–500°C, although the solubility decreased. BTC in water was converted to an insoluble material by addition of alkali or cuprous ammonia solution. The C/(H + Cl) ratio indicated the existence of three to five side groups for each twenty phenyl groups of the insoluble fraction, while that of the soluble fraction showed few such groups. The number increased to one or more side groups for each phenyl nucleus as both soluble and insoluble fractions were heated to 500°C. A thin film of soluble fraction deposited on a copper plate showed an electrical conductivity in the range 10^?2–10^?3 ohm^?1 cm^?1 at 25°C and an energy gap (ΔE_g) of 0.2–0.3 eV. However, a compressed specimen of the same soluble fraction showed little conductivity. Solventsoluble samples of substituted poly-4,4,-biphenylene were prepared by the same procedure. These materials cracked on processing, and accurate conductivity measurements could not be made.