Investigation of the elementary reactions in the synthesis of poly(hydroxethers) in dipolar,aprotic solvents

The effect of the hydroxyl groups of various phenols on the course of the reaction of their alkali metal salts with epichlorohydrin in dipolar, aprotic solvents has been studied. It was found that the presence of phenols in the system leads to the formation of a complex salt of the type (ArO … H … OAr)^?Mt⁺, and to a considerable decrease in the reaction rate. The mechanism of the reaction of chlorohydrin ethers of phenols with alkali metal phenolates was also studied. The effect of various factors on the course of the reaction of glycidyl ethers with phenols was determined by kinetic measurements.     

Solubility of sodium cellulose xanthate in aprotic solvents

Conclusions The solubility of sodium cellulose xanthate of various degrees of substitution in dipolar aprotic solvents has been examined.It has been shown that a xanthate with a low degree of substitution is soluble only in dimethyl sulfoxide, while a highly substituted one dissolves also in dimethylformamide, dimethylacetamide, and N-methylpyrrolidone.A water content in the aprotic solvent improves the solubility of the cellulose xanthate, but a sharp decrease in the degree of polymerization and degree of substitution also takes place.Translated from Khimicheskie Volokna, No. 1, p. 27, January–February, 1984.     

Water-soluble polymers by interaction of sulfonic polyelectrolytes with dipolar aprotic solvents

The solution of the strongly acidic polyelectrolyte poly(2-acrylamido-2-methylpropanesulfonic acid) in N,N-dimethylformamide or N,N-dimethylacetamide is accompanied by a simultaneous reaction of amidation of the sulfonic acid to the corresponding sulfonamide groups. Various compositions of binary copolymers poly[(2-acrylamido-2-methylpropanesulfonic acid)-co-(2-acrylamido-2-methylpropane-N,N-dimethylsulfonamide)] up to high amidation conversions of 98–99% were synthesized and characterized. The amidation of the sulfonic acid groups appears to be a common reaction for different copolymers having 2-acrylamido-2-methylpropanesulfonic acid moieties but fails with the free monomer.     

Conductance behavior of some tris(ethylenediamine)cobalt(III) complexes and their ion association in some dipolar aprotic solvents

The conductance behavior of dilute solutions of tris(ethylenediamine)cobalt(III) perchlorate in acetonitrile(AN), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and propylene carbonate (PC) was studied at 25°C. From the conductivities of these solutions the limiting molar conductivity of the tris(ethylenediamine)cobalt(III) ion and the ion association constant of the ion pair formed between the tris(ethylenediamine)cobalt(III) and the perchlorate ion have been determined. The Walden products of the tris(ethylenediamine)cobalt(III) ion in these solvents were found to be approximately constant. It was concluded from the ion association constants obtained that the degree of ion association was determined by not only the dielectric constant but also the basicity of these solvents. The ion association constants of tris(ethylenediamine)cobalt(III) ion with some anions which were determined from the conductivities of the dilute DMF and DMSO solutions at 25°C were found to increase to a great extent with the decrease in crystallographic radii of anions. The tendency could not be explained by the usual electrostatic theory. The conductance behaviour is discussed from the view point of the solvent effects which influence the ion-ion interaction.     

1,1-二氯-2,2-二氟乙烯的应用

介绍了1,1-二氯-2,2-二氟乙烯的性质,总结了它的各种合成方法,讨论了它在农药、医药等领域的应用。     

Flexibility and hydrodynamic properties of poly(vinylpyrrolidone) in non-ideal solvents

At 298.15K, intrinsic viscosity [] has been measured for poly (vinylpyrrolidone), PVP, samples of different relative molar masses M in pure water and eight different binary solvents. These solvents were water/acetone mixtures having different volume fractions of acetone (ACT). The solvation power of these mixtures showed a cosolvancy effect. The maximum solvation power was found for the mixture containing 0.2 volume fraction of ACT. The value of K=74×10^-3 dm³kg^-1 was utilized for calculating the unperturbed dimensions, u.d., steric factor, , the characteristic ratio, C, and the persistence length, a_p. Values of 0.666 A^o, 2.28, 10.38 and 8.76 A^o, respectively, were obtained for PVP in theta-solvent. The calculated values of the effective radius (R_e), effective unit length (b) and the effective hydrodynamic radius of monomeric unit (r_o) showed the complete impermeability of polymer molecules. Some errors in the polymer handbook and CRC, water-soluble synthetic polymers, were demonstrated with its logical corrections.     

2-氯-1,1-二氟乙烯的制备与应用

2-氯-1,1-二氟乙烯可用来制备含氟烯烃、烷烃和各类含氟化学品,应用广泛。本文详细介绍了2-氯-1,1-二氟乙烯的制备,并对其涉及的反应及应用进行了详细综述。     

Solubility characteristics of poly(etheretherketone) and poly(phenylene sulfide)

The crystalline high-performance polymers poly(etheretherketone) (PEEK) and poly(phenylene sulfide) (PPS) are generally considered to be highly resistant to dissolution in most common solvents. This article reveals numerous compounds that dissolve in excess of 25 wt % of each polymer at elevated temperatures. Typical binary-phase diagrams depicting the minimum solubility temperature vs. concentration are also presented for several representative polymer–solvent mixtures for both PEEK and PPS. The phenomenon of the solvent-induced crystallization of PEEK is presented. The importance of these polymer–solvent systems for the preparation of permselective membranes is discussed.     

Novel aprotic polar polymers 3. Synthesis and properties of poly(phenyl vinyl sulfoxide)

Summary Poly(phenyl vinyl sulfoxide) 1 was prepared by anionic polymerization and its properties as a polymer homolog of dimethyl sulfoxide (DMSO) were examined. Polysulfoxide 1 was found to have good miscibility with poly(vinyl acetate) as well as poly(2-methyl-2-oxazoline) and poly(N-vinylpyrrolidone) by comparing glass transition temperature(s) (T_gs) of the mixture of these polymers with T_gs of the original polymers by differential scanning calorimetry. Received: 4 March 1998/Accepted: 23 March 1998     

Anodic oxidation of furans in aprotic solvents

The anodic oxidation of furans in the presence of substituted 1,4-napthoquinones leads to coupling of the two. In the absence of the quinones, furan oligomers are formed. Further oxidation of these oligomers leads to the formation of conductive polymer films at the electrode surface.     

Solubility parameters of poly(di-n-alkyl cyclohexyl-) and poly(di-n-alkyl phenyl itaconates)

Solubility parameters of poly(dicyclohexyl-), poly(diphenyl itaconate) and of the first three members of the poly(dialkyl cyclohexyl-) and poly(dialkyl phenylitaconate) homologous series were determined from limiting viscosity numbers in various solvents and solvent mixtures, differing in structure, polarity and composition. The values obtained are within limits of 19.0 and 16.7 (J^1/2. cm^-3/2). Phenyl groups in the substituents lead to slightly higher values than cyclohexyl rings and the introduction of alkyl groups in both series results in a progressive decrease of the solubility parameter. The experimental values are slightly lower than those obtained by calculation from molar attraction constants.     

Synthesis of poly(ethyl vinyl ethers) containing two dipolar electronic systems and their properties

Summary 5-Nitro-2-(2′-vinyloxyethoxy)benzylidenemalononitrile (2a), methyl 5-nitro-2-(2′-vinyloxyethoxy)benzylidenecyanoacetate (2b), 3-nitro-4-(2′-vinyloxyethoxy)benzylidenemalononitrile (4a), and methyl 3-nitro-4-(2′-vinyloxyethoxy)benzylidenecyanoacetate (4b) were prepared by the condensation of 5-nitro-2-(2′-vinyloxyethoxy)benzaldehyde (1) and 3-nitro-4-(2′-vinyloxyethoxy)benzaldehyde (3) with malononitrile or methyl cyanoacetate, respectively. Vinyl ether monomers 2a-b and 4a-b were polymerized with boron trifluoride etherate as a cationic initiator to yield poly(vinyl ethers) 5-6 having nitrooxybenzylidenemalononitrile and nitrooxycyanocinnamate, which is effective chromophore for second-order nonlinear optical applications. Polymers 5-6 were soluble in common organic solvents such as acetone and DMSO. T _g values of the resulting polymer were in the range of 70–81°C. Electrooptic coefficient (r₃₃) of the poled polymer films were in the range of 19–27 pm/V, which was improved by introducing of nitro group. Polymers 5–6 showed a thermal stability up to 300°C in TGA thermograms, which is acceptable for NLO device applications. Received: 24 November 1998/Revised version: 19 January 1999/Accepted: 29 January 1999     

Poly(vinyl alcohol) functionalization with aldehydes in organic solvents: Shining properties of poly(vinyl acetals)

Poly(vinyl alcohol) has been functionalized with aldehydes in tetrahydrofuran (THF) with a good control of the grafting. A wide library of poly(vinyl acetals) could be obtained in order to study some structure/property correlations. The influence of the aldehyde nature on the functionalization rates has been studied, in particular for optical properties by measurement of the shininess for further applications in the cosmetic field. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40677.     

Solubility of tin ricinoleate in solvents

Summary Among the salts of ricinoleic acid available [aluminium (tri), barium, calcium, magnesium, zinc, and tin] the salt of tin shows the best solubility, in polar as well as in non-polar solvents (with the exception of glycols). In the case of diacetone alcohol the diacetone alcohol is soluble in tin ricinoleate, but novice versa. All the viscosities of the soap/solvent mixtures are according to the viscosities of the solvents. Normally there are no separations in phases, no swelling or thixotropic phenomena     

Solubility of poly(n-alkylmethacrylate)s in hydrocarbons and in alcohols

Poly(methylmethacrylate) (PMMA), poly(butylmethacrylate) (PBMA), and poly(decylmethacrylate) (PDMA) are completely miscible with toluene at normal pressure from room temperature up to the boiling point of the solvent. In alkanes (C₆ to C₁₀) and 1-pentanol the solubility increases with the length of the side chain of the polymer: PMMA always exhibits a solubility gap within the above temperature range, PBMA shows upper critical solution temperatures (except n-hexane, which is a non-solvent), and PDMA mixes completely with all alkanes under consideration. Alcohols (up to C₄) are non-solvents for PMMA but theta solvents for PBMA and PDMA (except ethanol which is a non-solvent for the latter). The low temperature demixing of ethanol/PBMA is shifted towards lower temperatures by pressure.     

Shrinkage and mechanical properties of poly(ethylene terephthalate) filaments treated with various organic solvents

The effects of a number of chemically nonreacting organic on shrinkage and stress–strain properties of preoriented semicrystalline poly(ethylene terephthalate) filaments have been studied. The changes in shrinkage and mechanical properties are found to be highly dependent on time and temperature, as well as on tension applied on the yarn during the treatment. The changes brought about by the solvents at lower temperatures (i.e., below 100°C) are either comparable with or more than those produced by thermal treatments in air or silicone oil above 200°C. The possibility of using slovent treatment for setting polyester for dimensional stability at low temperature as an alternative to the normal dry-heat-setting method has been discussed.     

Kinetics and isotope effects of the Dehydrochlorination of 1,1-dichloro-2,2-bis-(4-nitrophenyl) ethane with 1,5-diazabicyclo [4.3.0] non-5-ene in aprotic solvents

The kinetics of the reaction of 1,1-dichloro-2,2-bis-(4-nitrophenyl)ethane ( 1 ) with 1,5-diazabicyclo-[4.3.0]non-5-ene(DBN) in acetonitrile (MeCN), dichloromethane (DCM), tetrahydrofuran (THF), isopropylether (IPE) and hexane (Hex) solvents are reported. The reaction is a simple β-elimination forming 1-chloro-2,2-bis-(4-nitrophenyl)ethane ( 2 ) (100% conversion). The rate constants are similar for MeCN, THF, IPE, but lower by a factor of 2 and 7 for DCM and Hex respectively. The deuterium kinetic isotope effects k_H/k_D are between 10 and 6 for MeCN and Hex solvents. The entropies of activation (ΔS≠) are negative and large and show no correlation with the polarity of the solvents. The free enthalpies of activation (ΔG≠) are rather small (about 68 kJ mol⁻¹). The results are interpreted in terms of E2H with a contribution of (E1cB)_I mechanism.     

Diffusion of solvents in poly(vinyl acetate) and partially and fully hydrolyzed poly(vinyl alcohol)

Diffusivities of methyl acetate, methanol and water in poly(vinyl acetate) and fully and partially hydrolyzed poly(vinyl alcohol) have been measured by capillary column inverse gas chromatography and/or gravimetric sorption. Data from the literature have been used when available for comparison. Overall the diffusivities show good consistency in terms of their temperature and concentration dependences. The free‐volume model has been applied to all the data with excellent results. In most cases the dramatic changes in diffusivities with temperature and concentration can be captured using only a few experimental data points and two regression parameters. This demonstrates that the free‐volume theory is a valuable tool for the design of equipment for processing and devolatilization of polymer ? solvent systems. © 2013 Society of Chemical Industry     

Preparation and properties of porous gels from poly(l-lactic acid) and poly(d-lactic acid) with ionic liquids as solvents and porogens

We prepared poly(lactic acid) (PLA) porous gel materials by combining poly(l -lactic acid) and poly(d -lactic acid) of three different molecular weights in different mass ratios. Moreover, we used several imidazole-based ionic liquids with different anions as solvents and porogens at room temperature to prepare these materials. The properties of the resulting products were compared with those of materials prepared by sodium chloride as a conventional porogen and 1,4-dioxane as a solvent. The internal morphologies of the different types of materials were observed via scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and wettability analysis. The presented results should provide guidance and reference values for the preparation of PLA materials and for the improvement of their mechanical properties. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47058.