Behavior In Different Solvents Research Articles

Temperature‐Enhanced Solvent Vapor Annealing of a C3 Symmetric Hexa‐peri‐Hexabenzocoronene: Controlling the Self‐Assembly from Nano‐ to Macroscale

Temperature-enhanced solvent vapor annealing (TESVA) is used to self-assemble functionalized polycyclic aromatic hydrocarbon molecules into ordered macroscopic layers and crystals on solid surfaces. A novel C3 symmetric hexa-peri-hexabenzocoronene functionalized with alternating hydrophilic and hydrophobic side chains is used as a model system since its multivalent character can be expected to offer unique self-assembly properties and behavior in different solvents. TESVA promotes the molecule's long-range mobility, as proven by their diffusion on a Si/SiO(x) surface on a scale of hundreds of micrometers. This leads to self-assembly into large, ordered crystals featuring an edge-on columnar type of arrangement, which differs from the morphologies obtained using conventional solution-processing methods such as spin-coating or drop-casting. The temperature modulation in the TESVA makes it possible to achieve an additional control over the role of hydrodynamic forces in the self-assembly at surfaces, leading to a macroscopic self-healing within the adsorbed film notably improved as compared to conventional solvent vapor annealing. This surface re-organization can be monitored in real time by optical and atomic force microscopy.

Synthesis of Glycidyl Ether of Poly(bisphenol-A 1,1′-ferrocene dicarboxylate) and Its Electrochemical Behavior

A novel ferrocene-based epoxy compound of the glycidyl ether of poly(bisphenol-A 1,1′-ferrocene dicarboxylate) (GEPBFC) was synthesized and the electrochemical behavior of its films and solutions was investigated by cyclic voltammetry (CV). It was found that the GEPBFC films and solutions present different CV behavior in different solvents and the swelling ability of the solvent is the main factor that affects the CV behavior of GEPBFC films. The kinetic parameters of the film-electrode process, including the surface transfer coefficient, the apparent diffusion coefficient and the standard rate constant in LiClO4 ethanol solution, were calculated, and the corresponding electrode-process mechanism was discussed.

Synthesis of o‐[N‐(Substituted benzoyl)‐ N‐methylamino]phenyl Disulfides by the Spontaneous Coupling of N‐Methyl‐2‐mono(substituted phenyl)benzothiazolines in Solution and Their VEGF Inhibitory Activities

AbstractThe solid N‐methyl‐2‐mono(substituted phenyl)benzothiazolines (1) are stable and can be stored in atmosphere, whereas they present different behavior in different solvents. They are relatively stable in alcohol and DMSO‐H2O. However, in other organic solvents such as acetone, CH2Cl2, CHCl3, EtOAc etc., the oxidation‐coupling reactions occurred spontaneously to give the corresponding disulfide dimers 2. The substituents at 2‐phenyl rings, reaction temperature and the acidities of the solutions exerted obvious impacts on the reaction rates and yields of 2. 12 samples of N‐methyl‐2‐(substituted phenyl)benzothiazolines (1) and 11 dimers 2 were evaluated in vitro vascular endothelial growth factor (VEGF) inhibitory activity in human breast cancer cell MDA‐MB‐231 with 2‐methoxyestradiol (2‐ME) as the positive reference and most of them showed potent VEGF inhibitory activity with the EC50 values of sub‐millimolar range. Among them, the compounds 1l, 1i, and 2d showed potent VEGF inhibitory activities and selectivities with EC50 values of 0.07, <0.12, and 0.03 mmol/L and SI values of 25, >32 and >32, respectively, which were about 10 times of those of 2‐ME (EC50=0.49 mmol/L, SI=3.37). The results further demonstrated that the scaffolds of 1 and 2 were privileged and merited further investigation as VEGF inhibitors.

Preparation and characterization of novel hyperbranched poly(amine‐ester) films crosslinked by glutaraldehyde

AbstractNovel films based on hydroxyl terminated hyperbranched poly (amine‐ester) (HPAE‐OH) of different generation were prepared by crosslinking the terminal hydroxyl groups of HPAE with glutaraldehyde (GA). The progress of crosslinking reaction was characterized by Fourier transform infrared (FTIR) and viscosity measurement. The surface morphology of the crosslinked HPAE films was characterized by field emission scanning electron microscope (FE‐SEM) and atomic force microscopy. The results suggested that the films have homogenously dense interior matrices and smooth surface. The hydrophilicity/hydrophobicity of the crosslinked HPAE films was characterized by the water contact angle measurement. Variable swelling behavior in different solvents was also studied. The in vitro biocompatibility of the film was investigated by the bovine hemoglobin (Hb) adsorption measurement. And these results showed that these crosslinked HPAE films had excellent hydrophilicity, variable swelling behavior in different solvents, and relative low protein absorption. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Pressure induced graft-co-polymerization of acrylonitrile onto Saccharum cilliare fibre and evaluation of some properties of grafted fibre

In the present work, graft co-polymerization of acrylonitrile (AN) onto Saccharum cilliare fibre has been carried out in the presence of potassium persulphate and ferrous ammonium sulphate (FAS-KPS) as redox initiator. The reactions were carried out under pressure in an autoclave. Various reaction parameters such as pressure, time, pH, concentrations of initiator and monomer were optimized to get maximum graft yield (35·59%). Grafted and ungrafted Saccharum cilliare fibres were then subjected to evaluation of some of their properties like swelling behaviour in different solvents, moisture absorbance under different humidity levels, water uptake and resistance towards chemicals such as hydrochloric acid and sodium hydroxide. The characterization of the graft copolymers were carried out by FTIR spectrophotometer, X-ray diffraction (XRD) and scanning electron microscopic (SEM) studies.

Surfactant‐free synthesis of amphiphilic copolymer of poly(styrene‐co‐acrylamide) in aqueous emulsion with the assistance of ultrasound

AbstractThe hydrophilic monomer acrylamide (AM) and hydrophobic monomer styrene (St) have been directly copolymerized in a surfactant‐free aqueous emulsion with the assistance of powerful ultrasound. Fourier Transform Infrared spectrocopy (FT‐IR), nuclear magnetic resonance (NMR), and differential scanning calorimetry (DSC) measurements revealed that copolymers of AM and St were obtained. Elemental analysis was used to calculate the composition of the copolymer. Size exclusion chromatography (SEC) measurement showed that the molecular weight (Mw) of the copolymer is 1.86 × 105 g/mol and the polydispersity index (PDI( = 2.31. The self‐assembly behavior in different solvents was investigated utilizing laser light scattering (LLS), atomic force microscopy (AFM), and transmission electron microscopy (TEM); the copolymer film showed amphiphilicity, as measured by contact angle goniometry. Copyright © 2008 John Wiley & Sons, Ltd.

Unsaturation Effect on Gelation Behavior of Aryl Glycolipids

Structurally simple, renewable-resource-based cardanyl (glucoside)s [1, 1-O-3'-n-(pentadecyl) phenyl-beta-D-glucopyranoside; 2, 1-O-3'-n-(8'(Z)-pentadeceenyl)-beta-glucopyranoside; 3, 1-O-3'-n-(8'(Z),11'(Z)pentadecadienyl)phenyl-beta-D-glucopyranoside, 4; 1-O-3'-n-(8'(Z),11'(Z),14'-pentadecatrienyl)phenyl-beta-D-glucopyranoside; and the mixture 5] form thermally reversible transparent gels in a water/alcohol mixture and a number of organic solvents, strongly influenced by the unsaturation of the aliphatic alkyl chain. DSC studies revealed that the Tgel of 1 in water/ethanol (1:1, vol/vol) gel is 69.0 degrees C, while of the introduction of a single double bond reduces the value to 30.0 degrees C in the case of monoene 2, indicating that the stability of the gel is related to the number of double bonds on the lipophilic part of the gelator. Furthermore, XRD measurements showed that the aqueous gel 1 maintains an interdigitated bilayered structure with 3.14 nm long-range ordering, and the corresponding organogel maintains an extended bilayer structure for 4.34 nm, indicating a clear difference in the aggregation behavior in different solvents.

Synthesis and polymerization of the bromoacrylated plant oil triglycerides to rigid, flame‐retardant polymers

AbstractSimultaneous addition of bromine and acrylate to the double bonds of fatty acids in triglycerides was achieved. In the first part of the study, methyl oleate was bromoacrylated in the presence of acrylic acid and N‐bromosuccinimide as a model compound for the application of the reaction to the triglycerides. Next, soybean oil and high oleic sunflower oil were bromoacrylated by using the same procedure. The products were characterized by GC, IR, 1H‐NMR, 13C‐NMR, and mass spectrometry. The bromoacrylation yields for soybean oil and sunflower oil were 75 and 55%, respectively. A rigid thermoset polymer was prepared from the radical copolymerization of bromoacrylated soybean oil with styrene. The bromoacrylated sunflower oil–styrene copolymer showed semirigid properties. The crosslinked network structure of the copolymers was examined by their swelling behavior in different solvents. Glass‐transition temperatures were also determined and soybean oil–based polymer and sunflower oil–based polymer showed a glass transition at 55–65 and 20–30°C, respectively. The storage moduli of the soybean‐based and sunflower‐based polymers at room temperature were approximately 1.0 × 1010 and 1.1 × 108 Pa, respectively. Photopolymerization was also carried out by using 2,2‐dimethoxy‐2‐phenyl‐acetophenone as initiator. The response of the cured polymers to the thermal energy produced by a small flame was also tested by the ignition respond index method according to ASTM D 3713‐78 and was found to be 5 B at 2.00 mm. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91:2700–2710, 2004

A study of synthesis, characterization and catalytic hydrogenation by polymer anchored Pd(II)-amino acid complexes

Abstract l -Valine was anchored to 6% and 8% cross-linked poly(styrene-divinyl benzene) resin and its complex with palladium chloride was prepared. The newly synthesized catalysts were characterized by various techniques such as elemental analysis, FT-IR, DRS, SEM and TGA. Physico-chemical properties like surface area, swelling behavior in different solvents, bulk density, etc. have been determined. The polymer supported Pd complexes behave as versatile and recyclable catalysts for the hydrogenation of 1-octene, cyclohexene, acetophenone and nitrobenzene. Kinetics of hydrogenation of 1-octene has been investigated in detail. The influence of different reaction parameters on conversion and selectivity to products are reported.

Electronic structure in different environments for vanadyl porphyrinate molecules present in crude oil

The role of lateral chains in vanadyl porphyrinate is analyzed from a theoretical point of view. Three different vanadyl porphyrinate molecules are studied in different solutions, one with aliphatic substituents another with aromatic substituents and the molecule without substituents for comparison. The analysis of the results is mainly based on the behavior in different solvents, aromaticity measures, frontier molecular orbital changes and charge behavior. The isolated molecule is compared with the same molecule immersed in three different solvents, with low, medium and high values of dipole moment, tetrachloromethane, pyridine and acetone, respectively. The reactivity of the complexes is improved with the presence of the substituents without relevant aliphatic or aromatic nature, therefore, it is expected that the substituted molecules will be more pollutant to the catalysts than the molecule without substituents.

Olefin epoxidation catalysed by Mn(II) Schiff base complex in heterogenised–homogeneous systems

The polymer supported Mn(II) Schiff base complexes were prepared from crosslinked chloromethylated poly(styrene-divinyl benzene) copolymer beads by sequential modification into a Schiff base bearing ligand. These Schiff base bearing polymer on treatment with a solution of MnCl 2·2H 2O gave the corresponding metal complexes. The polymer supported Mn(II) complexes were characterised by elemental analysis, FT-IR, diffuse reflectance, SEM and thermogravimetric analysis. Physicochemical properties such as surface area, bulk density and swelling behaviour in different solvents were studied. The catalytic activity of the supported metal complexes were studied in the epoxidation of norbornene and cis-cyclooctene using tert-butylhydroperoxide (TBHP) as the terminal oxidant. The influence of various reaction parameters such as temperature, solvent, substrate and catalyst concentration, on conversion and selectivity has been studied.

Synthesis of Teflon-FEP grafted membranes for use in water desalination

Grafting of vinyl monomers containing polar pendant groups such as CN of 4-VP and C≡N of methacrylonitrile can impart desirable properties to the Teflon-FEP. In the present work grafting of 4-vinyl pyridine (4-VP) and mythacrylonitrile (MAN) onto Teflon-FEP film has been carried out by preirradiation method in aqueous medium. Optimum conditions for affording maximum percentage of grafting (Pg) have been evaluated. Maximum percentage of grafting of 4-VP (16.35%) at a total dose of 51.62 KGy was obtained ata monomer concentration of 0.93 moles/L. For MAN maximum percentage of grafting (31.70%) at a total dose of 49.90 KGy was obtained at a monomer concentration of 1.19 moles/L. Several grafting experiments were carried out in water-alcohol medium to study the effect of alcohols on Pg of 4-VP and MAN. The following order of different alcohols towards grafting of these monomers is observed. For 4-VP: Isopropanol > n-pentanol > ethanol > butanol > methanol. For MAN: Isopropanol > ethanol > methanol > butanol > n-pentanol. In all binary water-alcohol systems percentage of grafting was found to decrease with increasing amount of alcohol as compared to that obtained in the aqueous medium. The grafted Teflon-FEP films have been characterized by IR Spectroscopy, scanning electron microscopy, swelling behaviour in different solvents, percentage area change following grafting and by permeability behaviour.

Rigid, thermosetting liquid molding resins from renewable resources. I. Synthesis and polymerization of soy oil monoglyceride maleates

AbstractIn this study, rigid thermoset polymers were prepared from radical copolymerization of the soybean oil monoglyceride maleates with styrene. In the first part of the study, soybean oil monoglycerides (SOMGs) were obtained from the reaction of soybean oil with glycerol at 220–240°C with an optimization of the reaction to maximize the monoglyceride yield. In the following step, SOMG were reacted with maleic anhydride at temperatures around 100°C to produce the SOMG maleate half esters. Different catalysts and different reaction conditions were examined to increase the maleate half esters' yields. The reactions were followed by IR and 1H NMR, and the products were characterized by mass spectrometry. In the final step, the radical initiated copolymerization of the SOMG maleates with styrene produced rigid, thermoset polymers. The emulsion copolymerization of the SOMG maleates with styrene was also carried out successfully without the addition of an emulsifier. The obtained polymers were characterized by IR and the crosslinked network structure of the copolymers was examined with the swelling behavior in different solvents. Mechanical properties of the cured resin such as Tg, dynamic flexural modulus, and surface hardness were also determined. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 69–77, 2001

Catalytic activity of polymer-bound Ru(III)-EDTA complex

Chloromethylated styrene-divinylbenzene copolymer was chemically modified with ethylenediaminetetraacetic acid ligand. Catalytically active polymer containing Ru(III) moieties were synthesized from this polymeric ligand. They were characterized using FTIR, UV-vis, SEM, ESR and TGA. Other physico-chemical properties such as bulk density, surface area, moisture content and swelling behaviour in different solvents were also studied. The polymer bound complex was used to study hydrogenation of 1-hexene ton-hexane under mild conditions. Influence of [1-hexene], [catalyst], temperature and nature of the solvent on the rate of the reaction was investigated. A rate expression is proposed based on the observed initial rate data. Recycling efficiency of the catalyst has also been studied.

COORDINATION OF (4S, 9S)-4,9-DIETHYL-2,11-DIOXA-5, 8-DIAZA-1 δ5- PHOSPHATRICYCLO[6.3.0.01.5]UNDECANE WITH RETENTION OF HYDROPHOSPHORANE STRUCTURE: OBTAINING AND CHARACTERISTIC FEATURES OF ADDUCTS WITH BF3 AND ZnCl2

Reactions of tricyclic hydrophosphorane, (4s, 9S)-4, 9-diethyl-2, 11-dioxa-5, 8-diaza-1 δ5-phospha-tricyclo[6.3.0.01.5] undecane (1), with BF3×Et2O and with ZnCl2, under mild conditions have been investigated. The phosphorane ligand in the complexes obtained (2 and 3, respectively) was found to maintain its tricyclic structure, while the BF3 and ZnCl2 groups coordinate to the apical nitrogen and oxygen atoms of the trigonal bipyramid of phosphorane. The structure of the complexes has been evaluated by the following set of methods: IR and NMR 11B, 13C, 19F, 31P spectroscopy, mass-spectrometry, X-ray photoelectron spectroscopy, ultracentrifugation and elemental analysis. Spectral peculiarities and dynamic behavior in different solvents of compound 2 have been examined in detail.

Photochemical behaviour of oxyfluorfen: a diphenyl-ether herbicide

The photochemical behaviour in different solvents of the herbicide oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl) benzene (CAS RN 42874–03–3)] was studied. Photochemical reactions were carried out by using a high pressure mercury arc and a solar simulator. Kinetic parameters and quantum yields were determined. Identification of the photoproducts was performed by GC-MS and the main compounds were confirmed by [ 1H] NMR. The photochemical reactions were also carried out in the presence of either a singlet or a triplet quencher, and in the presence of either a radical initiator or a radical inhibitor. Results indicate that the first excited singlet state can undergo both homolytic and heterolytic cleavage of the ethyl-oxygen bond in the side chain of oxyfluorfen. Moreover, the presence of reduction products in the reaction mixture is supposed to occur via a monoelectron transfer process with the formation of a transient exciplex during the reaction.

Oxidation of benzyl alcohol using polymer anchored Ru(III) complex as catalyst

Polymer-anchored Ru(III) complex was synthesized by sequential attachment of ethylenediamine, salicylaldehyde and ruthenium chloride to chloromethylated styrene–divinylbenzene copolymer with 8% cross-linking. Synthesized catalyst was characterized by different techniques such as FTIR, reflectance UV-VIS spectroscopy, ESR, ESCA, SEM and TGA. Various physico-chemical properties such as moisture content, bulk density, surface area and swelling behaviour in different solvents were also studied. Catalytic activity of this catalyst was tested for oxidation of benzyl alcohol by varying the temperature of the system as well as concentration of substrate and catalyst. Values of energy of activation and entropy of activation have been evaluated from the kinetic data. A probable reaction mechanism has been proposed.

Polymer supported Ru(III) complexes, synthesis and catalytic activity

Crosslinked chloromethylated polystyrene-divinylbenzene polymers were chemically modified into Schiff base bearing ligands. Catalytically active metal supported polymers containing Ru(III) moieties were synthesized from these ligands for use in the selective epoxidation of olefins in presence of tert-butyl hydroperoxide as oxidant. These ruthenium anchored polymers were characterized by spectral and thermoanalytical methods. Catalyst morphology and physicochemical properties such as surface area, bulk density and swelling behaviour in different solvents were studied. The effects of reaction parameters such as catalyst concentration, temperature, time and solvent on conversion and selectively in the epoxidation of cis-cyclooctene and styrene are discussed.

Studies on asphaltene aggregation via computational chemistry

The aggregation of asphaltenes was studied using molecular modelling techniques. The solubility parameter of two different asphaltene average molecules and their aggregates was calculated. The results show a decrease in this parameter with increase of the aggregation state, in agreement with experimental evidence. Asphaltene behaviour in different solvents was studied by molecular dynamics simulations. A correspondence between the simulations and the experimental behaviour was found.

Microheterophase structure of A-B-A type block copolymer consisting of poly(γ-benzyl l-glutamate) as the a component and polyisoprene as the B component

A-B-A type block copolymers (GIG) composed of poly(γ-benzyl l-glutamate) (PBLG) as the A component and polyisoprene (PI) as the B component were synthesized. From the i.r. spectra measurements in the solid state, it has been found that the polypeptide chain block exists in the α-helix conformation in the same manner as PBLG. By using wide-angle X-ray diffraction (WAXD) and electron microscopy it could be shown that the block copolymers exhibit mesophase behaviour in different solvents. In this case, PI chains are in a random coil conformation and form domains embedded in the matrix phase formed by PBLG chains in the α-helix conformation. Model analysis of the complex modulus of the membrane cast from solution suggested the occurrence of spherical and cylindrical domain structures in the membrane.