共查询到20条相似文献,搜索用时 32 毫秒
1.
The interaction of poly(sodium sulfodecyl methacrylate) (PSSM) with cetyltrimethyl ammonium bromide (CTAB)was studied. It was found that the precipitate formed from PSSM and CTAB will be dissolved by excessive CTAB, resultingin the appearance of two maxima of the solution viscosity at the molar ratio (CTAB/-SO_3~-) of≈ 0.68 and≈1.30,respectively. The first one is related closely to the aggregation of polymer chains via CTAB molecules and the second oneshould be ascribed to the formation of the mixed micelles comprising surfactant and the polymer's hydrophobic chains. Theeffect of NaCl on the viscosity, the transmittance of the aqueous solution and the solubility of oil-soluble dye (dimethyl yellow) in the mixed system were also investigated. 相似文献
2.
Pure SnO2, sulfated SnO2-SO4
2- and Pd supported on SnO2 and SnO2-SO4
2- were prepared from SnO2 precursor with high surface area, and used for CH4 deep oxidation. The catalysts were characterized by means of N2-BET, XRD, TG-DTA, XPS and TPD. SnO2-SO4
2- shows higher activity than SnO2, due to the presence of more active oxygen species, superacid sites and its higher BET surface area. Pd/SnO2 and Pd/SnO2-SO4
2- display essentially the same activity to each other, while it is much higher than the activity on SnO2 and SnO2-SO4
2-. The main reason is ascribed to the concerted action between Pd and the supports. 相似文献
3.
Wolfram W. Rudolph 《Journal of solution chemistry》2010,39(7):1039-1059
Measurements have been made of the Raman spectra of aqueous solutions of Be(ClO4)2, BeCl2, (NH4)2SO4 and BeSO4 to 50 cm−1. In some cases low concentrations (0.000770 mol⋅kg−1) have been used and two temperatures (23 and 40 °C) were studied. In BeSO4(aq), the ν
1-SO42-\mathrm{SO}_{4}^{2-} mode at 980 cm−1 broadens with increasing concentration and shifts to higher wavenumbers. At the same time, a band at 1014 cm−1 is detectable with this mode being assigned to [BeOSO3], an inner-sphere complex (ISC). Confirmation of this assignment is provided by the simultaneous appearance of stretching
bands for the Be2+-OSO32-\mathrm{Be}^{2+}\mbox{-}\mathrm{OSO}_{3}^{2-} bond of the complex at 240 cm−1 and for the BeO4 skeleton mode of the [(H2O)3BeOSO3] unit at 498 cm−1. The ISC concentration increases with higher temperatures. The similarity of the n1-SO42-\nu_{1}\mbox{-}\mathrm{SO}_{4}^{2-} Raman bands for BeSO4 in H2O and D2O is further strong evidence for formation of an ISC. After subtraction of the ISC component at 1014 cm−1, the n1-SO42-\nu_{1}\mbox{-}\mathrm{SO}_{4}^{2-} band in BeSO4(aq) showed systematic differences from that in (NH4)2SO4(aq). This is consistent with a n1-SO42-\nu_{1}\mbox{-}\mathrm{SO}_{4}^{2-} mode at 982.7 cm−1 that can be assigned to the occurrence of an outer-sphere complex ion (OSCs). These observations are shown to be in agreement
with results derived from previous relaxation measurements. Infrared spectroscopic data show features that are also consistent
with a beryllium sulfato complex such as the appearance of a broad and weak n1-SO42-\nu_{1}\mbox{-}\mathrm{SO}_{4}^{2-} mode at ∼1014 cm−1, normally infrared forbidden, and a broad and asymmetric n3-SO42-\nu_{3}\mbox{-}\mathrm{SO}_{4}^{2-} band contour which could be fitted with four band components (including n3-SO42-(aq)\nu_{3}\mbox{-}\mathrm{SO}_{4}^{2-}(\mathrm{aq})). The formation of ISCs in BeSO4(aq) is much more pronounced than in the similar MgSO4(aq) system studied recently. 相似文献
4.
In order to improve the mechanical properties of polypyrrole, composites were made by electropolymerizing polypyrrole in a polyurethane matrix. Polypyrrole/polyurethane (PPY/PU) composite films containing CLO_4~-, BF_4~- or CH_3-C_6H_4-SO_3~- counter ions were made in a variety of solvent systems and characterized by SEM, electronic conductivity, FTIR, and mechanical properties. Composite films showing much greater fiexibility than pure polypyrrole were obtained, but their electronic conductivities were substantially lower. Measured eonductivities ranged from 0.001 to 8 S/cm, tensile strengths from 44 to 592 psi, and elongation to failure from 3 to 70%. 相似文献
5.
The effects of polycation structure, counterions and the nature of the solvent on the interaction between low-molecular-weight
salts with some cationic polyelectrolytes in water and methanol were investigated. The polyelectrolytes used in this study
were cationic polymers with quaternary nitrogen atoms in the backbone with or without a nonpolar side chain (polymer type
PCA5H1, PCA5D1 and PCA5) or tertiary amine nitrogen atoms in the main chain (polymer type PEGA). LiCl, NaCl, KCl, NaBr, NaI and Na2SO4 were used as low-molecular-weight salts. The interaction between polycations and salts was followed by viscometric and conductometric
measurements. The study of the interaction of monovalent counterions with cationic polyelectrolytes emphasized an increase
in the interaction with the decrease in the radius of the hydrated counterion, both for strong polycations and for weak polycations,
suggesting that counterion binding is nonspecific. In the case of SO2−
4 anions, the Λm−c
1/2 curve passes through a minimum at c
p values between 1 × 10−3 and 3 × 10−3 unit mol/l; this phenomenon can be explained by the maximum counterion interaction owing to the capacity of the polyvalent
counterion to bind two charged groups by intra- or interchain bridges. The investigation of the influence of the polycation
structure on the counterion binding indicated an increase in charged group–counterion interactions with a decrease in the
nonpolar chain length and an increase in the quaternary ammonium salt group content (charge density) in the chain. The polyelectrolyte
with tertiary amine groups in the chain, PEGA, showed, on one hand, a cation adsorption order as K+>Na+>Li+ and, on the other hand, a stronger association between ions and PEGA chains in methanol than in water owing to the poorer
solvating effect of methanol on the cations.
Received: 20 February 2001 Accepted: 29 June 2001 相似文献
6.
Volumetric properties of poly(acrylic acid) alkali-metal salts (Li, Na, K, Rb, and Cs) with different degrees of neutralization and water contents were studied in the range from pure solid to highly concentrated solutions. The apparent partial molar volume ?2 of the polymer and the partial molar volume V1 of water were calculated from density data. The value of ?2 decreased with decreasing polymer concentration and eventually leveled off. Values of V1, which at low water contents were much smaller than that of free water, increased with increasing water content and eventually reached a constant value equivalent to that of free water, thus indicating the appearance of free water. Water contents corresponding to the appearance of free water increased in the order of Li < Na < K < Rb < Cs, differing from the usual trend of hydration numbers observed in dilute solutions. The change of the slope of the plots of V1 versus composition suggested a change in the hydration mechanism. For Li, Na, and K salts, the limiting values of V1 at very low water content is considerably smaller than the 18 cm3/mol of free water. In contrast, for Rb and Cs salts, these values were relatively large, indicating the relatively weak electrostriction effects of these ions. 相似文献
7.
M. V. Fedotova O. A. Dmitrieva 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(5):794-797
The hydration structure of hydrophilic groups of L-proline zwitterion is studied by means of the 1D-RISM integral equation method. The structural parameters of hydration and features of hydrogen bonding between water and -NH 2 + and -COO? groups are discussed. 相似文献
8.
A poly(N-vinylimidazole) (PNVI)—based poly(carboxybetaine) with two methylene groups between the opposite charges was achieved by the nucleophilic addition reaction of the mentioned aminic polymer to the carbon-carbon double bond of acrylic acid (AA). Treatment of poly(carboxybetaine) with concentrated HCl (2 N) for long time leads to the corresponding cationic polyelectrolyte. The poly(carboxybetaine) is soluble in both water and aqueous solutions of salts such as: LiCl, NaCl, NaHCO3, CaCl2, Na2SO4. In water and in the first three salts, poly(carboxybetaine) exhibits a non-polyelectrolyte behaviour (a linear dependence of reduced viscosities on polymer or salt concentration), while in the remaining two salts, a slight polyelectrolyte behaviour is observed. The cationic polyelectrolyte is soluble in water and aqueous solutions of LiCl, NaCl, CaCl2 and NaHCO3, except Na2SO4. It has a polyelectrolyte behaviour in all solutions. Also, the binding trends of the added salts by polymers are discussed. 相似文献
9.
V. P. Korolev 《Journal of Structural Chemistry》2016,57(5):947-954
With an increase in the concentration of additives, the hydration numbers of compounds decrease. Thus, in a saturated 54.6% solution, urea loses approximately 3/4 of the initial amount of water, forming an aquacomplex of the composition (NH2)2CO?H2O. In a supersaturated 44% solution, the sodium chloride aquacomplex is dehydrated by 2/3, and in a supersaturated 67% solution, sodium sulfate is dehydrated by 5/6. The density of these solutions is 1.354÷1.360 g/cm3 (44% NaCl) and 1.800÷1.849 g/cm3 (67% Na2SO4). In a saturated urea solution, NaNO3, NaCl, and Na2SO4 complexes lose 53÷55% of hydration water. It is shown that the interactions in the binary water–urea system somewhat increase the hydration number of the salts (structural hydration). The hydration water density, a structurally important characteristic, increases in the series of solutions of urea, NaNO3, NaCl, and Na2SO4. In the same series of additives, the excess volume of binary water–urea and water–salt systems becomes more negative. 相似文献
10.
Jing Tang Shenhui Li Yueying Chu Yuqing Xiao Jun Xu Feng Deng 《Magnetic resonance in chemistry : MRC》2020,58(11):1091-1098
The acid strength of metal–organic frameworks plays a key role in their catalytic performance such as activity and selectivity during catalytic reactions. Solid-state nuclear magnetic resonance in combination with probe molecules including 2-13C-acetone and pyridine-d5 was employed to characterize the acid strength of UiO-66-X (X = -H, -2COOH, -SO3H). It was found that after introduction of the functional groups, the acid strength of UiO-66-2COOH and UiO-66-SO3H is considerably enhanced compared with that of parent UiO-66, with that of the former being similar to that of zeolite H-ZSM-5, and with that of the latter being slightly stronger than that of the former. Even though the acid density can efficiently be modified through changing the relative ratio in multivariate functionalized UiO-66-X, no significant alternation for the acid strength could be discerned in the MTV-UiO-66-X compared with acidic same-link counterpart. Theoretical calculations were employed to further confirm the acid strength of UiO-66-SO3H and UiO-66-2COOH. 相似文献
11.
Abstract To prepare electrolytes using poly(organophosphazenes), poly(bisanilinophosphazene) selected was carried out with the various concentration of sulfonic chloride in tetra-chloroethane solvent using vigorously sterring at room temperature for 4 hr. The products prepared were determined with IR and chemical analysis. It was found that the -SO3H groups in the product appeared at 1,1050 cm?1, 1,030 cm?1 and 550 cm?1, and the reaction rate of sulfonic chloride was about 34%-55% under this experimental conditions. Also, the products had two kind of glass transition temperatures such as 63°C and -18°C, respectively, and the values were lower in comparison with that of starting polymer. Furthermore, the conductivity of the product at room temperature was determined and the conductivity was increased the concentration of -SO3H groups. It was found that the product having -SO3H groups was able to ion exchange with Li+ or Cu2+ ions under aqueous solution. Also, the ion exchange rate was determined with the titration of alkaline aqueous solution with a standard solution of HCl. The products formed after the ion exchange reaction had higher conductivity in comparison with that of the polymer. 相似文献
12.
The hydration of camphene was carried out over SBA-15 with sulfonic acid groups and tungstophosphoric acid at 50 °C. The main product of camphene hydration was isoborneol, with camphene hydrate and borneol as byproducts. The catalytic activity increased with the amount of tungstophosforic acid (PW) immobilized on the silica support until a maximum, which was obtained with the PW4-SBA-15-SO3H material (16.4 wt.%). When the amount of PW immobilized on SBA-15 increased (PW5-SBA-15-SO3H, 21.2 wt.%), the catalytic activity decreased. The catalytic activity of PW4-SBA-15-SO3H increased with the water content of the solvent, until a maximum was reached with 50% water. With higher water concentrations, a decrease in the catalytic activity was observed. The selectivity to isoborneol was 90% at 99% camphene conversion in the presence of the PW4-SBA-15-SO3H catalyst. The catalytic stability of the PW4-SBA-15-SO3H material during camphene hydration was studied by performing consecutive batch runs with the same catalyst sample. After the third run, a trend towards stabilized catalytic activity was observed. A kinetic model is also proposed. 相似文献
13.
Dynamic 1H NMR (500 MHz) investigation of 4-methylphenoxyimidoyl azides (4-CH3-C6H4-O-CN-Y)-N3, Y=4-CH3-C6H4-SO2-, 4-Br-C6H4-SO2-, C6H5SO2-, CH3-SO2-, -CN in acetone-d6 at temperature range of 195-280 K is reported. The observed free energy barrier (almost 12 kcal mol−1) is attributed to conformational isomerisation about the N-S bond for Y=4-CH3-C6H4-SO2-, 4-Br-C6H4-SO2-, C6H5SO2-, CH3-SO2- and (almost 14 kcal mol−1) to configurational isomerisation (E/Z) about CN bond for Y=-CN. 相似文献
14.
A series of four different dilithium salts of structure F3CSO2N(Li)SO2-(CF2)x-SO2N(Li)SO2CF3, with x = 2, 4, 6, 8 were synthesized and characterized in polyethylene-oxide-based solid polymer electrolytes. Each salt may be thought of as two bis[(perfluoroalkyl)sulfonyl]imide anions linked together by a perfluoroalkyl chain of a particular length. Taken together, this homologous series provides an opportunity to study the effects of linker chain length and degree of fluorination in dianionic (and ultimately polyanionic) salts on the properties, particularly the conductivity, of the salts in various solvating media. SPEs in polyethylene oxide were characterized using scanning calorimetry, X-ray diffraction, 1H and 19F NMR, and electrochemical impedance spectroscopy for SPEs prepared using ethylene-oxide-oxygen-to-lithium (EO:Li) ratios of 10:1 and 30:1. Trends in SPE ionic conductivity with anion structure revealed an unexpected trend whereby ionic conductivity is generally rising with increased length of the perfluoroalkylene linking group in the dianions. This trend could be the result of a decrease in dianion basicity that results in diminished ion pairing and an enhancement in the number of charge carriers with increasing anion fluorine content, thereby increasing ionic conductivity. 相似文献
15.
David W. Allen Leslie Ebdon 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):161-165
Abstract The polarographic reduction of series of heteroaryl- and heteroarylmethylphosphonium salts has been studied using a differential pulse polarographic technique, this having a number of advantages over classical dc polarography. For the salts Ar3P+CH2PhBr-, the observed order of ease of reduction correlates with the electron-withdrawing ability of the heteroaryl group (i.e. Ar = 2-furyl > 2-thienyl > phenyl > 1-methylpyrrol-2-yl). In contrast, for the salts Ph3P+CH2ArBr- (Ar = 2-furyl, 2-thienyl, phenyl, 1-methylpyrrol-2-yl, 3-thienyl and 3-furyl), the ease of reduction correlates best with the order of stability of the forming carbanions as established in earlier studies of the alkaline hydrolysis of these salts. 相似文献
16.
The extraction of Co2+ by mixtures of acetylacetone (acac) and either pyridine (Py), benzylamine (ba), triethylamine (tea) or tripyridylamine (tpa)
bases in xylene solvent was investigated from an aqueous phase containing salts of LiCl, NaCl, KCl, RbCl and CsCl in concentrations
varying up to 3M. The different hydration properties of the alkali metal cations is show to affect very slightly the synergistic
solvent extraction of Co2+. This result, together with previously obtained thermodynamic data indicating the nonexistence of water molecules in the
extracted synergistic species, may explain the fact that these salts have no effect on the extraction of Co(acac)2 (N-base)2. 相似文献
17.
Tohru TakeiTakumi Ohki Yosuke HaradaNaoto Kumagai Hiroki FukumotoTake-aki Koizumi Akihiro MaedaTakahiro Kojima Yoshihisa SeiKohei Shiramizu Masahiro AbeMasashi Oota Takakazu Yamamoto 《Tetrahedron letters》2012,53(44):5907-5910
Dibromopyridines or dibromopyridone with -(CH2)m-SO3Na group(s) has been prepared via the reactions of the corresponding dibromopyridines with -OH and -NH2 groups with sultone. These compounds were converted into polymers with the -(CH2)m-SO3H groups via organometallic polycondensation. The polymer showed proton conducting properties and high stability toward oxidation. 相似文献
18.
钙镁磷肥(FCMP)阴离子构型的硅烷化气相色谱(TMS-GC)研究 总被引:1,自引:0,他引:1
通过对钙镁磷肥(FCMP)硅烷化气相色谱(TMS-GC)的研究证明:FCMP中硅以一聚、二聚、三聚链及环四构型为主,同时还有少量其他一维、二维、三维构型存在;而磷则以单个四面体与硅聚合或独立存在。 相似文献
19.
2D materials can be functionalised with various ionisable functional groups of different formal charges, forming the so-called 2D electrolytes. In this study, 2D electrolytes based on functionalised graphene oxide (GO) with cationic groups (-NH3+) and molybdenum disulfide (MoS2) with anionic groups (-COO-) were used to form heterostructures through a self-assembly process. Due to the presence of opposite charges, heterostructures were formed by the predominantly attractive forces between the 2D electrolytes in a fluidic aqueous environment. With the application of sonication, both 2D materials were able to overcome the energy barrier offered by their bending stiffness, continuously assembling and scrolling into heterostructured nanofibers. The nanofibers were the product of the conjugated 2D electrolytes, which led to their phase separation and precipitation into highly ordered and high aspect ratio 1D structures. As the reaction proceeds, long nanofiber bundles with branches were formed, resembling the structures formed by naturally occurring polyelectrolytes such as amino acids forming proteins. This method offers a facile approach for the continuous processing of heterostructured nanofibers with a low production cost under flow that can be widely applied in textiles, encapsulation technologies, and nanosensors. 相似文献
20.
Arthur J. Banister Anthony W. Luke 《Journal of polymer science. Part A, Polymer chemistry》1992,30(12):2653-2656
Mono-, bis- and tris-(1,3,2,4-dithiadiazolium) salts [R-(CNSNS +)n]n+[AsF-6]n (R = aryl, n = 1, 2, 3) were found to initiate the cationic ring-opening polymerization of tetrahydrofuran (THF) at room temperature to give clear gels from which the pure polymer was precipitated. 1,3,2,4-Dithiadiazolium cations associated with the hard [AsF6]- anion thus constitute a new class of cationic polymerization initiators. The poly(THF) formed by initiation with 1,3,2,4-dithiadiazolium cation was characterized by gel permeation chromatography, infrared spectrophotometry, and 13C-NMR spectroscopy. Number-average molecular weights of 198 700 g mol-1 (polydispersity 1.96) and 190 000 g mol-1 (polydispersity 1.61) were obtained using [PhCNSNS ] [AsF6] and [C6H3-1,3,5-(CNSNS )3][AsF6]3, respectively, as initiators. The use of multifunctional dithiadiazolium salts as initiators suggests that they may be useful in the preparation of starburst and dendritic polymers. © 1992 John Wiley & Sons, Inc. 相似文献