Biphenyl Methane Research Articles

Chromium doped zinc nanoferrites as highly selective catalysts for Friedel Craft’s reaction

Different compositions of chromium doped zinc nanoferrites prepared by sol-gel method were assessed as Friedel Crafts catalysts for benzylation of benzene. The un-doped chromium ferrite composite showed maximum catalytic efficacy in the series effecting complete conversion of benzyl chloride in 60 min at 363 K with 100% selectivity for biphenyl methane. The effect of reaction parameters were thoroughly investigated along with a correlation analysis of surface acidity of the catalyst with its efficiency and selectivity towards the reaction. An attempt has also been made on the reaction kinetics and Arrhenius behavior of the catalyzed reaction.

Development of Nickel Doped Zinc Ferrite Nanocomposites as Magnetically Recoverable Catalytic Material for The Synthesis of Biphenyl Methane

Magnetically active nickel doped zinc ferrite nanoparticles with chemical composition NixZn1-xFe2O4 (x- 0.0, 0.25, 0.5, 0.75 and 1.0) were successfully synthesized by sol-gel auto-combustion method using high purity metal nitrates and ethylene glycol as gelling agent. The prepared samples were characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), X-ray Fluorescence (XRF) and Fourier Transform Infra-Red spectral (FTIR) analyses. TEM images and particle size distribution profile reveals the agglomeration tendency during nickel doping suggest the magnetic nature of particles. The remarkable change in the magnetic behaviour of nickel doped zinc ferrite samples provide an easy recovery and regeneration of the material and thus making an excellent candidate for benzylation reaction without any remarkable fall in the catalytic performance for repeated cycles.

A Sustainable Heterogeneous Iron Catalyst Fe/SBA‐15 towards Direct Arylation of Unactivated C(sp3)−H and C(sp2)−H Bonds with Arenes

AbstractIron grafted over mesoporous silica (8 wt %Fe/SBA‐15) is a sustainable, efficient heterogeneous iron catalyst for direct arylation of biphenyl methane C(sp3)−H and benzene C(sp2)−H bonds. The selective extraction deposition (SED) technique was adopted to graft iron easily over the mesoporous support SBA‐15 by using LaFeO3 as an iron precursor. The synthesized catalyst has been characterized by EPR spectroscopy, diffuse reflectance UV/Vis spectroscopy, and temperature programmed reduction (TPR) analysis to understand the coordination environment and state of oxidic iron species grafted over the mesoporous SBA‐15. TPR results confirm the presence of isolated, clustered, oligomeric oxidic iron species in the catalyst. The adopted SED technique is highly successful for grafting 8 wt % iron into the mesopores of SBA‐15 without forming iron oxide particles. Unlike homogeneous iron, the 8 wt %Fe/SBA‐15 catalyst does not need support from an electron‐withdrawing group and additives to carry out arylation of benzene and could be successfully recycled five times.

Ferrocene Based Azo Chromophore Functionalized Polyesters and Its Organic Analogue: Synthesis, Structural Elucidation, Thermal Behavior and IV Characterization

Azo-functionalized polyesters were synthesized via a low temperature solution polycondenstion of 4,4′-bis(4-azo-1-hydroxyphenyl)biphenyl methane (A) with four different diacid chlorides [terephthalyolchloride (T), isophthaloyl chloride (I), trans-azobenzene-4,4′-dicarbonyl chloride (TA) and ferrocenedicarboxylic acid chloride (Fe)]. The synthesized polymers were characterized by FTIR and 1HNMR spectrophotometric techniques and the structural property relation was studied in terms of solubility measurements, WAXRD, bleeding test, viscosities and UV/Visible spectroscopic analysis. Thermal properties were explored by means of thermogravimetric analysis and differential scanning calorimetry. LOI values, calculated by using the Van Krevelen–Hoftyzer equation were found in the range 35–37.8. Conductivity measurements showed that ferrocene based polymer were most conducting material with maximum conductivity 4.56 × 10−4 Scm−1. The material had relative viscosities in range 1.585–1.128 dL/g showing high molecular weights.

Rearrangement of Ethers: A New Route to Tolterodine

The rearrangement of benzyl phenolic ether in the presence of an acid or AlCl3 is utilized to produce biphenyl methane compounds in very good yields. The synthesis of muscarine receptor antagonist tolterodine is described.

Study on BMI modified allyl‐functional novolac resin/silica cloth composites: Effect of allylation degree on thermal and mechanical properties

AbstractA series of allyl‐functional novolac resin with various allylation degree, from 32.4 to 114.6%, were synthesized and then blended reactively with 4,4′‐bismaleimide biphenyl methane (BMI) at a weight ratio of 2.50:1 to get BMI‐modified allyl‐functional novolac (BMAN) resins. BMAN resins were used as matrix resin to fabricate BMAN/Silica cloth composites by compression molding process. Heat‐resistant properties of the composites were evaluated by means of dynamic mechanical analysis. The results indicated that thermal resistance of the composites increased as allylation degree of BMAN resins increased. Mechanical properties of the composites, including interlaminar shear strength (ILSS) and flexural strength at room temperature and 300°C, were determined, and the results showed that with increase in allylation degree of matrices the ILSS and flexural strength values of composites at room temperature decreased, but the values of ILSS and flexural strength at 300°C increased. Scanning electron microscope morphology analysis of fracture surface for composites revealed that tough interphase was responsible for the better mechanical properties of the composites based on lower allylation degree resins. POLYM. COMPOS., 28:180–185, 2007. © 2007 Society of Plastics Engineers

The effect of allylation degree on processing properties, thermal cure, and thermal properties of BMAN resins

A series of allyl-functional novolac (AN) resins with various allylation degree, from 32.4 to 114.6%, were synthesized and blended reactively with 4,4′-bismaleimide biphenyl methane (BMI) at a weight ratio of 2.50 : 1 to get BMI-modified and allyl-functional novolac (BMAN) resins. Structural characteristics of the resins were determined by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1HNMR) techniques. Processing properties of BMAN resin system was evaluated by solubility, rheology, and thermal gelation, and the results show that processing properties of BMAN resins were excellent and could be tailored by changing allylation degree of AN resins. Differential scanning calorimetry (DSC) was used to evaluate cure reactivity of BMAN resin system, and the results reveal that the resins with higher allylation degree possessed better cure reactivity. Thermal properties were evaluated by means of dynamic mechanical analysis (DMA) and thermogravimetry analysis (TGA) techniques. The results reveal that with increase in allylation degree of resins the thermal stability of BMAN resins increased because of increase in crosslinking density, but char-yields of the above resins at 800°C decreased in turn. Understanding of the relationship between allylation degree and properties of the resins would be useful to direct the design of material to meet different requirements of applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

New mesogens with a fluoro-substituted bent core

Ferroelectric properties in liquid crystals are no longer restricted to materials with a chiral molecular structure; ferroelectricity has been observed in a smectic phase formed by bent achiral molecules. Accordingly, two homologous series possessing a central biphenyl methane core have been synthesized, the central core having two lateral fluoro substituents. Both the series have six-ring structures and exhibit smectic mesophases of high thermal stability. The flexible biphenyl methane core imparts a slight curve to the molecules, giving them a bent shape.

Influence of interface on radiation effects of crystalline polymer—radiation effects on polyamide-1010 containing BMI

Aimed at saving the radiation dose required to crosslinking the polyamid-1010, BMI/PA1010 systems containing different amounts of difunctional crosslinking agent N,N'-bis-maleimide-4,4'-biphenyl methane (BMI) were prepared and the structure changes at the crystallographic and supermolecular levels before and after irradiation were studied by using WAXD, SAXS, and DSC techniques. It was found that by incorporation of BMI the microcrystal size L-100 is lowered due to the formation of hydrogen bond between the carbonyl oxygen of BMI and the amide hydrogen of PA1010 in the hydrogen bonded plane, and the overall crystallinity W-c is also decreased. The presence of BMI causes the crystal lamella thickness d(c) to decrease and greatly thickens the transition zone d(tr) between the crystalline and amorphous regions. As for the irradiated specimen, the maximum increments in the L-100 and W-c against dose curves decrease with BMI content, and the interception point D-i, at which the L-100 and W-c curves intercept their respective horizontal line of L-100/L-100(0) and W-c/W-c(0)=1, shift to lower dose with an increase in BMI concentration. In addition. the mechanism of the radiation chemical reactions in the three different phases under the action of BMI are discussed with special focus on the interface region. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.

Novel Bismaleimide - Epoxy Resin System: III

Novel diamines, namely N,N′-bis[1-(4-aminophenyl) ethanonyl]-4,4′-(1,1′-biphenyl)diamine (DA1), N,N′-bis[1-(4-aminophenyl) ethanonyl]-4,4′-(1,1′-biphenyl methane) diamine (DA2) and N,N;-bis[1-(4-aminophenyl) ethanonyl]-4,4′-(oxybisphenyl)diamine (DA3) have been prepared and reacted with various bismaleimides (BM) at a BM: diamine ratio of 1:2. The resulting oligoimides have been characterized by elemental analysis, IR spectral studies, and thermogravimetry. Their number average molecular weights ([Formula: see text]n) were estimated by nonaqueous conductometric titration. All of the oligoimides have been used as curing agents for epoxy resins based on the diglycidyl ether of bisphenol-A, and studied by differential scanning calorimetry (DSC). Glass and carbon fibre reinforced composites have also been prepared and characterized by mechanical properties.

Novel Bismaleimide - Epoxy Resin System: III

Novel diamines, namely N,N′-bis[1-(4-aminophenyl) ethanonyl]-4,4′-(1,1′-biphenyl)diamine (DA1), N,N′-bis[1-(4-aminophenyl) ethanonyl]-4,4′-(1,1′-biphenyl methane) diamine (DA2) and N,N;-bis[1-(4-aminophenyl) ethanonyl]-4,4′-(oxybisphenyl)diamine (DA3) have been prepared and reacted with various bismaleimides (BM) at a BM: diamine ratio of 1:2. The resulting oligoimides have been characterized by elemental analysis, IR spectral studies, and thermogravimetry. Their number average molecular weights ([Formula: see text]n) were estimated by nonaqueous conductometric titration. All of the oligoimides have been used as curing agents for epoxy resins based on the diglycidyl ether of bisphenol-A, and studied by differential scanning calorimetry (DSC). Glass and carbon fibre reinforced composites have also been prepared and characterized by mechanical properties.