Study by gas-liquid chromatography of the thermodynamics of the interaction of poly(vinyl acetate) with various solvents

The solubility parameter of poly(vinyl acetate) at various temperatures has been obtained by using the method developed by DiPaola-Baranyi and Guillet, Marcomolecules11, 228 (1978). The solubility parameter of polymer at 25°C was found to be $\text{10.1 (}\text{cal/cm}{}^3\text{)}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ by linear extrapolation from higher temperatures (70–140°C). The interaction parameter χ of polymer in various solvents, at temperatures below the melting point T_m, has been determined by means of the solubility parameters of the polymer and solvents at this temperature, deduced from their values obtained chromatographically at higher temperatures. The value of the interaction parameter so obtained is in good agreement not only with values calculated by other techniques but also is independent of the temperature range used for the chromatographic measurements. Moreover, using the equation-of-state theory formulation, we have determined the values of the interaction parameters $\text{χ}{}^1$ for various systems poly(vinyl acetate)/probes and from it the contact interaction energy, X₁₂, in the temperature range 70–140°C.     

Compatibility in poly(ethylene oxide)–poly(methyl methacrylate) blends

The compatibility of poly(ethylene oxide)-poly(methyl methacrylate) (PEO-PMMA) blends were examined covering the complete composition range. Up to 20% of PEO content films were transparent and glass transition temperatures were determined by DSC and by refractive index vs. temperature measurements. Only one T_g was obtained for these samples and the relationship between T_g and composition has been evaluated. At higher PEO content crystallization took place and the films were opaque. Melting temperatuures of PEO in blends were determined by DSC. Melting point depression was observed for increasing proportion of PMMA and the binary interaction parameter has been calculated.     

Uniaxial drawing of poly(ethyleneoxide)/poly(methyl methacrylate) blends by solid-state extrusion

Ultradrawn ribbons of solution-cast blends of poly(ethylene oxide) (PEO)/poly(methyl methacrylate) (PMMA) have been prepared by a solid-state coextrusion in a capillary rheometer. An increase of noncrystallizable PMMA in the blends drastically decreased the drawability from a draw ratio of 36 for pure PEO to 5 for a mixture of PEO/PMMA 40/60% by weight. A low crystallinity and depression of melting temperature for PEO were observed with increasing draw. The Flory-Huggins theory for melting temperature depression has been used to derive the binary interaction parameter for these blends.     

Ternary interaction parameters in n-hexane/butanone (MEK)/poly(dimethylsiloxane) (PDMS) and n-heptane/MEK/PDMS systems

Second virial coefficients, A₂, intrinsic viscosities, [η], and solvation preferential coefficients, γ, for the ternary systems n-hexane, HEX, (1)/butanone, MEK, (2)/poly(dimethylsiloxane), PDMS, (3) and n-heptane, HEP, (1)/MEK (2)/PDMS (3) have been determined at 20.0°. Binary interaction parameters, g₂, have also been measured by light scattering. Inversion in γ at $\text{u}{}_2\text{? 0.15}$ in the HEX system and at $\text{u}{}_2\text{? 0.22}$ in the HEP system takes place. The inversion points are accompanied by smooth maxima in A₂ and in [η]. Both systems show a weak cosolvent character. Theoretical γ's derived, according to Flory-Huggins and Flory-Prigogine-Patterson, are compared with experimental values. The evaluation of the ternary interaction potential, g_T, and its dependence on system composition allow evaluation of the binary interaction potentials and their dependence on polymer concentration.     

Synthesis and chemistry of HC(SO2F)3 and cis- and trans(HO)2TeF4

HC(SO₂F)₃ has been prepared and characterized. It turned out to be a strong acid, comparable to mineral acids. In aqueous solution the salts of the type Cs⁺C(SO₂F)₃^? are formed. The anion, as found by crystal structure analysis contains planar CS₃ configuration.Quite in contrast to these findings HC(OSO₂F)₃ is not even soluble in water.Derivatives of HC(SO₂F)₃ have been prepared so far CH₃C(SO₂F)₃ FC(SO₂F)₃ ClC(SO₂F)₃ BrC(SO₂F)₃ JC(SO₂F)₃The heavier halogen derivatives ( Cl, Br, J ) are oxidizing agents (‘positive halogen’).A mixture of $\text{cis-}$ and $\text{trans-}$ (HO)₂TeF₄ is obtained if HOTeF₅ and Te(OH)₆ are melted together. The mixture of the isomeres have been transfered into the corresponding silylesters $\text{cis}$- and $\text{trans-}$ (R₃SiO)₂TeF₄, which could be separated by fractional crystallisation and distillation.Without conformational change the pure silylesters have been reacted back to pure $\text{cis}$- (HO)₂TeF₄ and $\text{trans}$- (HO)₂TeF₄ by means of anhydrous HF. Both $\text{cis-}$ and $\text{trans}$ (HO)₂TeF₄ have been reacted with ClF to give $\text{cis}$- and $\text{trans}$- (ClO)₂TeF₄, yellow liquids. The latter react with elemental bromine to the rather unstable $\text{cis-}$ and $\text{trans-}$ (BrO)TeF₄, red liquids.Starting with $\text{cis}$-(HO)₂TeF₄ and XeF₂ a polimer Xenon compound of the formula

All materials have been characterized by melting point and vapour pressure, 19 F - nmv spectroscopy, vibrational spectroscopy, and elemental analysis.     

VISCOMETRIC STUDY OF POLY(METHYL METHACRYLATE) AND POLYSTYRENE BLENDS IN DIFFERENT SOLVENTS

The intermolecular interaction between poly(methyl methacrylate) (PMMA) and polystyrene (PS) intetrahydrofuran (THF) and N,N'-dimethyl formamide (DMF) solvents was studied at 28℃ using a dilute solution viscometrymethod. Solvent is believed to play a key role in characterizing the viscosity behavior of the polymer solution. The intrinsicviscosity and viscosity interaction parameter were experimentally measured for the binary (solvent/polymer) and for theternary systems in two solvents. The compatibility of the polymer mixture was discussed in terms of the sign of △b_m. Theresults show that the compatibility of PMMA/PS blend in DMF is larger than that in THF.     

Miscibility in blends of poly(3-hydroxybutyrate) and poly(vinylidene chloride-co-acrylonitrile)

Miscibility behavior of poly(3-hydroxybutyrate) [PHB]/poly(vinylidene chloride-co-acrylonitrile) [P(VDC-AN)] blends have been investigated by differential scanning calorimetry and optical microscopy. Each blend showed a single T_g, and a large melting point depression of PHB. All the blends containing more than 40% PHB showed linear spherulitic growth behavior and the growth rate decreased with P(VDC-AN) content. The interaction parameter χ₁₂, obtained from melting point depression analysis, gave the value of −0.267 for the PHB/P(VDC-AN) blends. All results presented in this article lead to the conclusion that PHB/P(VDC-AN) blends are completely miscible in all proportions from a thermodynamic viewpoint. The miscibility in these blends is ascribed to the specific molecular interaction involving the carbonyl groups of PHB. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2645–2652, 1997     

Ligandbewegungen in űbergangsmetallkomplexen XI 1H-NMR-spektroskopische untersuchungen an acetylacetonat-bis(olefin)-rhodium(I)-komplexen

The temperature-dependent ¹H NMR spectra of acetylacetonatebis(ethylene)-rhodium, (acac)Rh(C₂H₄)₂ (I), of some related complexes containing methoxy-substituted ethylenes have been measured in toluene-d₈ solution. Both monosubstituted [(acac)Rh(C₂H₄)(olefin), olefin = tetramethoxyethylene (II), $\text{cis}$- and $\text{trans}$-dimethoxyethylene (III and IV)] and disubstituted [(acac)Rh(olefin)₂, olefin = $\text{cis}$- and $\text{trans}$-dimethoxyethylene (V and VI), methyl vinyl ether (VII)] derivatives of I have been investigated with respect to hindered intramolecular movements of the ligands. The barriers of olefin rotation increase with an increasing number of methoxy substituents. When the olefin rotation is frozen out; the methoxy substituents of the olefins tend to be turned away from the acetylacetonate ligand unless steric interaction occurs between the two π-coordinated olefins. A hindered movement of the acetylacetonate ligand has been observed in II and V. For this movement which is independent of the olefin rotation, a degenerate rearrangement is proposed of the tetragonal-planar complexes via a tetrahedral transition state.     

The kinetics of photo-initiated oxidation of poly(p-methylstyrene) in solution

The photo-initiated oxidation of poly(p-methylstyrene) has been studied at 25°C in chlorobenzene solution, initiating radicals being produced by the photolysis (λ = 313 nm) of AIBN. The effects of polymer concentration, 313 nm intensity (I₀), AIBN concentration and oxygen pressure have been examined and a rate expression of the form:

$\text{?}\text{d(O}{}_2\text{)}\text{dt}\text{α(O}{}_2\text{)}{}^0\text{(}\text{Polymer}\text{)}{}^{0.6}\text{(}\text{AIBN}\text{)}{}^{0.95}\text{(I}{}_0\text{)}{}^{1.05}$

was obtained. (pO₂ > 300 mbar.)A reaction scheme which accounts for the rate expression is described. The decrease in molecular weight on oxidation is accounted for in terms of hydroperoxide decomposition.The relative reactivities of poly(styrene) and poly(p-methylstyrene) are compared, the latter being more reactive towards oxidation. Reaction at the p-CH₃ group is not ruled out.     

Solution properties of an aqueous poly(methacryl oxyethyl trimethylammonium chloride) and its poly(oxyethylene) grafted analog

Cationic poly(methacryl oxyethyl trimethylammonium chloride), PMOTAC, and its poly(oxyethylene), POE, grafted analog have been synthesised. The molar mass of the POE grafts was M_w = 200 g/mol, and the grafting degrees of the synthesised copolymers were 2, 5, and 15 mol %. The effect of the POE grafts on the solution properties and the conformation of the polycation has been investigated in aqueous NaNO₃ by means of dynamic and static light scattering, viscometry, and Raman spectroscopy. It was found that the polyelectrolyte properties are more pronounced for the homopolymer than for the POE‐grafted copolymers. The increase of the POE‐grafting degree dramatically decreases the hydrodynamic radius of individual macromolecules and causes intermolecular association. It also suppresses the conformational response of the copolymers upon changing the ionic strength with respect to that of the homopolymer. DFT calculations have been used to estimate a possible mechanism of interaction between the POE grafts and the MOTAC repeating units. It has been revealed that the POE grafts are capable of forming intramolecular hydrogen bonds with the MOTAC groups. The latter was confirmed experimentally; addition of free POE chains to a solution of PMOTAC results in formation of intermolecular PMOTAC/POE complexes. Increasing the POE concentration decreases the solution viscosity. At the same time, the bimodal distributions of the hydrodynamic radius, which are typical for polyelectrolytes in salt‐free solutions, become monomodal representing the PMOTAC/POE complexes. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 547–557, 2008     

Adenosine cyclic 3′,5′-(RP)- and (SP)-phosphoramidates,the first representatives of nucleoside cyclic 3′,5′-phosphoramidates derived from ammonia

Adenosine cyclic 3′,5′-phosphoramidate $\text{2}$ was synthesized by reacting adenosine cyclic 3′,5′-phosphate $\text{1}$ with POCl₃, in trimethyl phosphate for 1 h at O°C, followed by in situ treatment of the reaction mixture with a suspension of (NH₄)₂CO₃ in anhydrous DMF or pyridine or DMF/pyridine mixture for 30 min at 25° C. Diastereoisomers ($\text{R}$_P)-$\text{2}$ and ($\text{S}$_P)-$\text{2}$ the relative quantities of which depended on the solvent of (NH₄)₂CO₃ treatment, were separated by reversed phase partition chromatography. Hydrolysis of (R_P)-$\text{2}$ and (S_P)-$\text{2}$ proceeded with predominant (90% in 0.1 N HCl, 100% in 0.1 N NaOH) -P-O-C bond breaking.     

The assessment of miscibility and morphology of poly(ε-caprolactone) and poly(para-chlorostyrene) blends

The miscibility and morphology of poly(ε-caprolactone) (PCl) and poly(para-chlorostyrene) (PpClS) blend were investigated by using thermal analysis, morphological analysis, viscometry, and the study of melting point depression. A single glass transition temperature was observed by differential scanning calorimetry (DSC) for PCl/PpClS blends in the whole compositional range (0/100, 25/75, 50/50, 62.5/37.5, 75/25, 90/10). Morphology of the polymers and their blends was studied by scanning electron microscopy (SEM). The Fourier transform infrared spectra of the samples were obtained by spectrometer. Up to 12 cm⁻¹ shifts in carbonyl stretching band of PCl was detected in the spectra of PpClS rich blends. The viscosity of PCl, PpClS and their blends has also been studied to investigate the miscibility according the miscibility criteria Δb, and Δ[η]. Using this data, the interaction parameters α and μ, based on the Chee and Sun et al. approaches were determined. These criteria indicated that the blend is miscible in all proportions up to 90% of PCl content in the blends. The melting point depression of PCl in the blends was examined to obtain the interaction parameter, χ₁₂ for this system. The parameter, χ₁₂ was found to be composition dependent. Negative values of the obtained interaction parameter also support the miscibility of this system up to the 90% PCl in the blend.     

Synthesis and solution properties of poly[2-methoxy-4,6-di(p,p′-isopropylidene diphenyloxy)-s-triazine] I

Poly[2-methoxy-4,6-di(p,p′-isopropylidene diphenyloxy)-s-triazine] has been synthesized by interfacial polycondensation of 2-methoxy-4,6-dichloro-s-triazine with bisphenol A. The conditions have been optimized to prepare a sample of both high solubility and molecular weight. The polymer has been fractionated by fractional precipitation and the fractions characterized by viscometry, osmometry and gel permeation chromatography. Mark-Houwink-Kuhn-Sakurada (MHKS) expressions have been developed for three solvents. The values of unperturbed dimensions $\text{(<R}{}^2\text{>}{}_0\text{/M)}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$, solvent-polymer interaction parameter (B and χ₁) and conformational parameter (σ) have been computed by applying the two-parameter theories of excluded volume developed by Fixman, Kurata, Stockmayer and Roig and by Flory, Fox and Schaefgen.     

Synthesis of 2-alkylthio (or trifluoromethylthio)-2-halogenoethenyl derivatives by means of wittig (under phase transfer conditions) or wittig-horner reactions. Application in the field of pyrethroids

A mixture of RSCHCl₂, Ph₃P and $\text{trans}$-caronaldehyde ethyl ester, treated with aq.NaOH under phase transfer conditions, gave the corresponding 2-alkylthio,2-chloroethenyl derivative, the product of the Wittig reaction of a phosphorane formed 'in situ'. The analogous derivative of the $\text{cis}$- and the 2-methylthio, 2-bromoethenyl derivative of the $\text{trans}$-caronaldehyde ethyl ester were synthesized also by means of Wittig-Horner reactions. The 2-trifluoromethylthio, 2-chloro-ethenyl derivative of the caronaldehyde ethyl ester ($\text{cis}$-$\text{trans}$ mixture) was also obtained through the phosphonate prepared from CF₃Cl + N₂CHP(OET)₂→ CF₃SCHClP(O)(OEt) The new derivatives prepared were converted to final pyrethroids by esterification with cyano(m-phenoxyphenyl)methanol.     

Methylated multibridged [2n]cyclophanes. All alternate synthesis of [26](1,2,3,4,5,6) cyclophane (superphane)

A sequence of formylation followed by a carbene insertion reaction has led to the stepwise introduction of additional ethano bridges into 4,5,7,8- tetramethyl [2₂](1,4)cyclophane ($\text{1}$), providing syntheses of 5,7,8-trimethyl- [2₃](l,2,4)cyclophane ($\text{6}$), a mixture of 5,8-dimethyl[2₄(1,2,4,5)cyclophane ($\text{10}$) and 5,7-dimethyl[2₄(1,2,3,5)cyclophane ($\text{11}$, and-4-methyl[2₅](1,2,3,4,5)-cyclophane ($\text{14}$). This route to $\text{14}$ completes a formal eight-step synthesis of [2₆](1,2,3,4,5,6)cyclophane ($\text{15}$, superphane) with an overall yield of 17%. A Birch reduction of $\text{6}$ readily gave 12,15-dihydro-5,7,8-trimethyl[2₃](1,2,4)-cyclophane ($\text{7}$) in 85% yield.     

The interaction of an osmium-carbon triple bond with copper(I), silver(I) and gold(I) to give mixed dimetallocyclopropene species and the structures of Os(AgCl) (CR) Cl(CO) (PPh3)2

The osmium carbyne complex, Os(CR)Cl(CO)(PPh₃)₂, (R  p-tolyl) reacts with Group I halides to form the mixed dimetallocyclopropene species, $\text{Os(Cul)(C}$R)Cl(CO)(PPh₃)₂, $\text{Os(AgCl)(C}$R)Cl(CO)(PPh₃)₂, $\text{Os(AuCl)(C}$R)Cl(CO)(PPh₃)₂, and [$\text{Os[Ag(OClO}{}_3\text{)](C}$R)Cl(CO)(MeCN)(PPh₃)₂] ClO₄ X-ray crystal structure determination of $\text{Os(AgCl)(C}$R)Cl(CO)(PPh₃)₂ confirms the presence of a three-membered ring and the structure can be viewed as the “acetylene-like” interaction of an osmium—carbon triple bond with AgCl. In acid solution AgCl is precipitated and an alkylidene complex results from proton addition to the carbyne ligand.     

Effect of the form and the parameters of intermolecular interaction potential on calculated values. Henry constant for adsorption of noble gases on graphitized black and the specific surface area determined therefrom

The effect of the form and the parameters of the atom-atom potential of intermolecular interaction, as well as that of the approximations used in its summation over the atoms of a solid, on the values of the Henry constant $\text{K}$₁ for the adsorption of noble gases on the basal face of graphite has been examined. At fixed values of the depth and of the position of the atom-atom potential minimum, $\text{K}$₁ values are only slightly sensitive to the form of this potential, if its summation is performed taking into account the layer structure of graphite. Disregarding the laminated structure of the graphite lattice leads to highly underestimated values of $\text{K}$₁. The values of the parameter $\text{c}$₁ of the attractive forces of the potential (6, 8, exp) for the intermolecular interaction of the atoms of noble gases with the carbon atom of graphite have been determined, using experimental values of $\text{K}$₁ for the adsorption of these gases on graphitized thermal carbon blacks. The corresponding changes in internal energy, entropy and heat capacity have been calculated.The effect of the form and the parameters of the potential function φ of the intermolecular interaction of a monoatomic molecule with the basal face of graphite on the energy φ_o in the minimum of the potential curve φ($\text{z}$), and on the product $\text{sz}$_o of the specific surface area $\text{s}$, and the equilibrium distance between the molecule and the surface $\text{z}$_o, has been studied. φ_o and $\text{sz}$_o were determined from experimental values of the Henry adsorption constant $\text{K}$₁ measured at different temperatures. From the experimental values of $\text{K}$₁ for the adsorption of noble gases, the value of $\text{s}$ for graphitized thermal carbon black Sterling PT, 2700 (P-33), has been determined. This value of $\text{s}$ does not essentially depend on the adsorbate and lies within the limits of error of the $\text{s}$ value, determined for this carbon black by the BET method. When determining $\text{s}$ from $\text{K}$₁, it is necessary to take into account the structure of the solid so as to choose the form of potential φ correctly. Values of $\text{z}$_o should be determined from the atom-atom potential function of the adsorbate-adsorbent intermolecular interaction.     

Perfluoroalkyl derivatives of nitrogen. Part LI [1]. Reaction of the N-halogenobistrifluoromethylamines (CF3)2NX (X=Cl,Br) with norbornadiene

Reaction of the amines (CF₃)₂NX (X=Cl,Br) with norbornadiene either in solvent (CH₂Cl₂) at ?78 °C in the dark or in the vapour phase at 20 °C in daylight gives a mixture of 3-halogeno-5-($\text{NN}$-bistrifluoromethylamino)nortricyclene ($\text{exo}$, $\text{endo}$-and $\text{exo}$, $\text{exo}$-isomers) and $\text{exo}$-5-($\text{NN}$-bistrifluoromethylamino)- $\text{anti}$-7-halogenonorbornene in quantitative yield formed $\text{via}$ halonium ion addition to the diene. The reaction of the amine (CF₃)₂NBr in solvent Me₂O or Et₂O at ?78 °C in the dark gives the same products in low yield, together with 3-bromo-5-alkoxynortricyclene ($\text{exo}$, $\text{endo}$- and $\text{exo}$, $\text{exo}$-isomers) and the amine (CF₃)₂NR (R=Me, Et) in high yield.     

Dilute solutions of nylon 12—II. Relationship between intrinsic viscosity and molecular weight

Samples of poly(12-dodecanelactam) (polylaurolactam, nylon 12) with $\text{M}$_n 1 × 10³?33 × 10³ were prepared. Polymerizations initiated with water or with lauric acid proceeded under conditions for minimum changes in end-group concentration. Values of $\text{M}$_n were calculated from the end-group content and $\text{M}$_n from light scattering in the mixture m-cresol/60 vol% of 2.2,3,3-tetrafluoropropanol. From measurements of intrinsic viscosity in m-cresol, the relationship [n] ? $\text{M}$_n was established in the given range of $\text{M}$_n. The relationship [n] ? $\text{M}$_w for $\text{M}$_w from 3.3 × 10³ to 125 × 10³ has been established.     

An unusual chlorination of 1-phenyl-4-(2,6-dichlorophenyl)-1,3-butadiene

The diene $\text{1a}$ reacted with CHCl₃/aq. NaOH/PTC in CH₂ Cl₂ unexpectedly to give a mixture of the chlorination products $\text{2}$ and $\text{3a}$. Usual chlorination with Cl₂ yielded similarly $\text{2}$, $\text{3a}$, and $\text{3b}$ dependent on the amount of Cl₂. The formation of $\text{2}$ as well as the reaction of $\text{7}$ to give $\text{9}$ (besides $\text{8}$) shows an unusual Cl-Cl-interaction.