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1.
The charge-transfer complex formed between an amine and carbon tetrachloride can initiate the polymerization of vinyl monomers in a nonaqueous solvent such as dimethylsulfoxide. Here we use cyclopentylamine (CPA) and heptylamine (HA) as the donor compounds for charge-transfer initiation of the polymerization of methl methacrylate (MMA). The rate of polymerization Rp = k[MMA]1 [amine]0.5 [CCl4]0.5 when [CCl4] [amine] ≤ 1; when [CCl4] [amine] < 1, Rp becomes independent of [CCl4] and Rp = k[MMA]1.5 [amine]0.5. The average constant at 60°C for the polymerization of MMA in terms of monomer were (1.66 ± 0.03) × 10?5 and (1.46 ± 0.04) × 10?5 s?1 with CPA and HA, respectively, when [CCl4] [amine] ≤ 1, and (1.16 ± 0.04) × 10?5 and (1.39 ± 0.08) × 10?1 L/mol·s when [CCl4]/[amine] < 1. 相似文献
2.
The charge-transfer complex formed by the interaction of an aliphatic amine, such as n-butylamine (nBA), and carbon tetrachloride (CCl4) in dimethylsulphoxide (DMSO) initiates polymerization of methyl methacrylate (MMA) at 30°. The rate of polymerization is given by Rp = k[MMA]0.83 [nBA]0.5 [CCl4]0.5 when [CCl4]/[nBA] is ? 1. When [CCl4]/[nBA] > 1, Rp is independent of [CCl4] and Rp = k[MMA]1.46 [nBA]0.5. The average rate constants are (1.42 ± 0.05) × 10?6 1 mol?1 sec?1 in terms of MMA and (2.20 ± 0.06) × 10?6 sec?1 at 30° for higher and lower concentration of carbon tetrachloride respectively. A charge-transfer mechanism for polymerization is suggested. 相似文献
3.
2-Vinyl pyridine (2-VP) can be initiated by a charge-transfer complex formed by the interaction of aliphatic amines such as n-butylamine (nBA) and carbon tetrachloride (CCl4) in a solvent like NN-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). This article describes the polymerization of 2-VP by n-butylamine (nBA) in the presence of carbon tetrachloride in DMSO at 60°C. The rate of polymerization Rp increases rapidly with carbon tetrachloride (CCl4) up to a concentration of 3.93 mol/L, but for a higher concentration it is almost independent of the carbon tetrachloride concentration; Rp is proportional to [nBA]0.5 and [2-VP]1.5 when [CCl4]>[nBA]. The average rate constant k is 1.03 × 10?5 L/mol s. When [CCl4] < [nBA] the rate constant in terms of [2-VP] was 1.06 × 10?5 s?1 at 60°C and the overall rate constant was 1.035 × 10?5 L/mol s at 60°C. 相似文献
4.
P. C. Dwivedi Archana Srivastava R. S. Rathi 《Journal of polymer science. Part A, Polymer chemistry》1990,28(12):3279-3291
Polymerization of methyl methacrylate (MMA) with aliphatic primary amines and carbon tetrachloride has been investigated in th dimethylsulfoxide medium by employing a dilatometric technique at 60°C. The rate of polymerization (Rp) has been evaluated under the conditions, [CCl4]/[amine] < 1 and > 1. The kinetic data indicate possible participation of the charge transfer complexes formed between the amine + CCl4 and the amine + MMA in the polymerization of MMA. In the absence of CCl4 or amine, no polymerization of MMA was observed under the present experimental conditions. The polymerization of MMA was inhibited by hydroquinone, indicating a free radical initiation. The energy of activation varied from 32 to 58 kJ mol?1. 相似文献
5.
Ruthenium trichloride (RuCl3 or RuIII) catalyzed polymerization of methylmethacrylate (MMA) initiated with n‐butylamine (BA) in the presence of carbon tetrachloride (CCl4) by a charge‐transfer mechanism has been investigated in a dimethylsulfoxide (DMSO) medium by employing a dilatometric technique at 60°C. The rate of polymerization (Rp) has been obtained under the conditions [CCl4]/[BA] ? 1 and [CCl4]/[BA] ? 1. The kinetic data indicate the possible participation of the charge‐transfer complex formed between the amine–RuIII complex and CCl4 in the polymerization of MMA. In the absence of either CCl4 or BA, no polymerization of MMA is observed under the present experimental conditions. The rate of polymerization is inhibited by hydroquinone, suggesting a free‐radical initiation. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 43: 70–77, 2011 相似文献
6.
Homopolymerization of methyl methacrylate (MMA) was carried out in the presence of triphenylstibonium 1,2,3,4-tetraphenyl-cyclopentadienylide
as an initiator in dioxane at 65°C±0·l°C. The system follows non-ideal radical kinetics (R
p
∝ [M]1·4 [I]0·44
@#@) due to primary radical termination as well as degradative chain-transfer reaction. The overall activation energy and average
value ofk
2
p
/k
t
were 64 kJmol−1 and 0.173 × 10−3 1 mol−1 s−1 respectively 相似文献
7.
Studies on direct-current electrical conductivity and optical properties of a new solution of processable conducting polymer
are reported. Electrical conductivity of thin films of the polymer on glass plate at room temperature was 6×10−6 S/cm. Study of conductivity with variation of temperature does not provide any definite thermal activation energy, which
is in accordance with the amorphous nature of polymer. Optical absorption data adopting the Bardeen equation showed that maximum
‘optical gap’ (E
g
) is 3.30 eV. Doping with Br2-vapor was found to be only partially effective in decreasingE
g
by 0.43 eV. The polymer was found to be quite stable under normal atmospheric conditions. Environmental stability of both
undoped and doped polymer has been discussed.
Part 2: [5] 相似文献
8.
Relative enthalpies for low-and high-temperature modifications of Na3FeF6 and for the Na3FeF6 melt have been measured by drop calorimetry in the temperature range 723–1318 K. Enthalpy of modification transition at 920
K, δtrans
H(Na3FeF6, 920 K) = (19 ± 3) kJ mol−1 and enthalpy of fusion at the temperature of fusion 1255 K, δfusH(Na3FeF6, 1255 K) = (89 ± 3) kJ mol−1 have been determined from the experimental data. Following heat capacities were obtained for the crystalline phases and for
the melt, respectively: C
p(Na3FeF6, cr, α) = (294 ± 14) J (mol K)−1, for 723 = T/K ≤ 920, C
p(Na3FeF6, cr, β) = (300 ± 11) J (mol K)−1 for 920 ≤ T/K = 1233 and C
p(Na3FeF6, melt) = (275 ± 22) J (mol K)−1 for 1258 ≤ T/K ≤ 1318. The obtained enthalpies indicate that melting of Na3FeF6 proceeds through a continuous series of temperature dependent equilibrium states, likely associated with the production of
a solid solution.
相似文献
9.
The sorption of anions H2PO4
−, HPO4
2−, PO4
3−, [Fe(CN)6]3−, and [Fe(CN)6]4− from aqueous solutions on the surface of FeIII and ZrIV oxyhydroxide hydrogels freshly precipitated at pH 4–13 was studied. The region of sorbate concentrations was from 0.00025
to 0.06 mol L−1. The plots of the anion uptakes vs. their equilibrium concentrations are represented by isotherms of the first type, which are well described by the Langmuir
equation if the quantity of the amount adsorbed is expressed as mol-site g−1. The maximum uptakes and constants of the Langmuir equation were calculated. The phosphate anions occupy the same number
of sorption sites on the sorbents precipitated at different pH. The average specific content of sorption sites for the ferro-
and zirconogels in the metastability period is independent of the pH of their precipitation, being 3.1·10−3 and 3.2·10−3 mol-site g−1, respectively. The [Fe(CN)6]3− and [Fe(CN)6]4− anions are sorbed only on the positively charged sites of the hydrogels and occupy not more than 2·10 mol-site g−1 in the studied interval of pH of precipitation.
__________
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1736—1741, August, 2005. 相似文献
10.
Clemente Bretti Concetta De Stefano Claudia Foti Ottavia Giuffrè Silvio Sammartano 《Journal of solution chemistry》2009,38(10):1225-1245
Protonation constants of one thiocarboxylate (thioacetate) and four sulfur-containing carboxylates (2-methylthioacetate, thiolactate,
thiomalate, 3-mercaptopropionate) were determined by potentiometric measurements in a wide ionic strength range [0≤I≤5 mol⋅L−1 in NaCl and 0 ≤I≤3 mol⋅L−1 in (CH3)4NCl] at t=25 °C. For two of these ligands (2-methylthioacetate and thiolactate), the protonation enthalpies were also determined by
calorimetric measurements in NaCl ionic medium [0 ≤I≤5 mol⋅L−1] at t=25 °C. Individual UV spectra of the protonated and unprotonated 3-mercaptopropionate species, together with values of the
protonation constants, were obtained by spectrophotometric titrations. Results were analyzed in terms of their dependence
on the ionic medium by using different thermodynamic models [Debye-Hückel type, SIT (Specific ion Interaction Theory) and
Pitzer’s equations]. Differences among protonation constants obtained in different media were also interpreted in terms of
weak complex formation. 相似文献
11.
Stephanie A. Moore Subhash C. Bhattacharya Rama M. Palepu 《Journal of solution chemistry》2006,35(4):471-483
The photophyscial behavior of the dye Safranine T in the ground and excited states in aqueous mixtures of glycol oligomers was investigated by absorption and fluorescence spectroscopic techniques. The formation of a 1:1 complex in the excited state was inferred from fluorescence studies. The calculated equilibrium constants of the complex are directly proportional to the molar mass of the glycol. Microviscosity values of the aqueous glycol mixtures were determined by employing Auromine O as a fluorescence probe. Stokes shift values were correlated with the bulk dielectric constant and the microviscosity of the media. Also employing Stokes shifts, solvent parameters such as the Kowoser Z values and the intramolecular charge transfer energy, E
T
(30), were evaluated. The fluorescence quenching of Safranine T by the inorganic ions [Fe(CN)6]3−, [Fe(CN)6]4−, and [I]− in aqueous oligomer mixtures at a fixed concentration was investigated. The ions influenced the quenching process to different extents, and the efficiency of quenching of the dye in the glycol media for [Fe(CN)6]4− and [I]− ions follows the order EG > DEG > TEG > TTEG. In the case of ferricyanide ion the reverse order was observed. The microviscosity and bulk dielectric constant of the media played a major role in the collisional quenching process. 相似文献
12.
Eric Da Silva Cécile F. Rousseau Isabelle Zanella-Cléon Michel Becchi Anthony W. Coleman 《Journal of inclusion phenomena and macrocyclic chemistry》2006,54(1-2):53-59
Electrospray Ionization Mass Spectrometry (ESI/MS) has been used to determine the association constants (KAs) and binding stoichiometries for parent para-Sulphonato-calix[n]arenes and their derivatives with bovine serum albumin (BSA). KA values were determined by titration experiments using a constant concentration of protein. KA measurements were carried out in a methanol–formic acid solution. 5,11,17,23–tetra-Sulphonato-calix[4]arene (1a) and 25-mono-(2-aminoethoxy)-5,11,17,23-tetra-Sulphonato-calix[4]arene (1d) interact strongly with BSA showing 3 non-equivalent binding sites with KA1 = 7.69 × 105 M−1, KA2 = 3.85 × 105 M−1, KA3 = 0.33 × 105 M−1 and KA1 = 1.69 × 105 M−1, KA2 = 2.94 × 105 M−1, KA3 = 0.60 × 105 M−1, respectively. The strength of the interactions between the calixarene and BSA is inversely proportional to the size of macrocyclic
ring: n = 4 > n=6>>n=8. 相似文献
13.
J. Wang Y. Wang Zh. H. Zhang X. D. Zhang J. Tong X. Zh. Liu X. Y. Liu Y. Zhang Zh. J. Pan 《Journal of Structural Chemistry》2005,46(5):895-905
Syntheses and structure determination of the YIII complexes with ethylenediaminetetraacetic acid (H4edta) and trans-1,2-cyclohexanediaminetetraacetic acid (H4cydta) are reported. The crystal and molecular structures of the complexes, as well as their molecular formulas and compositions,
were determined by single-crystal X-ray structure analyses, NMR, IR, thermogravimetric measurements, and elementary analyses.
The crystal of the Na[YIII(edta)(H2O)3]·5H2O complex belongs to the orthorhombic crystal system and space group Fdd2. The crystal data are as follows: a = 19.355(5) Å, b = 35.431(11) Å, c = 12.122(3) Å, V = 8313(4) Å3, Z = 16, M = 544.23, Dc = 1.739 g·cm−3, μ = 2.908 mm−1 and F(000) = 4480. The final R and Rw are 0.0483 and 0.1172 for 3284 (I > 2σ(I)) unique reflections, R and Rw are 0.0678 and 0.1440 for all 8499 reflections, respectively. The YIIIN2O7 part in the [YIII(edta)(H2O)3]− complex anion has a pseudo-monocapped square antiprismatic nine-coordinate structure, in which the six coordinated atoms
(two N and four O) from the edta ligand and three water molecules are coordinated to the central YIII ion directly. The crystal of the Na[YIII(cydta)(H2O)2]·5H2O complex belongs to the triclinic crystal system and
space group. The crystal data are as follows: a = 8.405(2) Å, b = 9.970(2) Å, c = 14.763(4) Å, α = 88.538(4)°, β = 76.193(4)°, γ = 88.100(4)°, V = 1200.6(5) Å 3, Z = 2, M = 580.31, Dc = 1.605 g·cm−3, μ = 2.519 mm−1 and F(000) = 600. The final R and Rw are 0.0381 and 0.0911 for 4198 (I > 2σ(I)) unique reflections, R and Rw are 0.0530 and 0.1041 for all 6186 reflections, respectively. The YIIIN2O6 part in the [YIII(cydta)(H2O)2]− complex anion has a pseudo square antiprismatic eight-coordinate structure in which the six coordinated atoms (two N and
four O) from the cydta ligand and two water molecules are coordinated to the central YIII ion directly.
Original Russian Text Copyright ? 2005 by J. Wang, Y. Wang, Zh. H. Zhang, X. D. Zhang, J. Tong, X. Zh. Liu, X. Y. Liu, Y.
Zhang, and Zh. J. Pan
__________
Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 5, pp. 928–938, September–October, 2005. 相似文献
14.
The stoichiometries, kinetics and mechanism of the reduction of tetraoxoiodate(VII) ion, IO4
− to the corresponding trioxoiodate(V) ion, IO3
− by n-(2-hydroxylethyl)ethylenediaminetriacetatocobaltate(II) ion, [CoHEDTAOH2]− have been studied in aqueous media at 28 °C, I = 0.50 mol dm−3 (NaClO4) and [H+] = 7.0 × 10−3 mol dm−3. The reaction is first order in [Oxidant] and [Reductant], and the rate is inversely dependent on H+ concentration in the range 5.00 × 10−3 ≤ H+≤ 20.00 × 10−3 mol dm−3 studied. A plot of acid rate constant versus [H+]−1 was linear with intercept. The rate law for the reaction is:
- \frac[ \textCoHEDTAOH2 - ]\textdt = ( a + b[ \textH + ] - 1 )[ \textCoHEDTAOH2 - ][ \textIO4 - ] - {\frac{{\left[ {{\text{CoHEDTAOH}}_{2}^{ - } } \right]}}{{{\text{d}}t}}} = \left( {a + b\left[ {{\text{H}}^{ + } } \right]^{ - 1} } \right)\left[ {{\text{CoHEDTAOH}}_{2}^{ - } } \right]\left[ {{\text{IO}}_{4}^{ - } } \right] 相似文献
15.
Clemente Bretti Francesco Crea Ottavia Giuffrè Silvio Sammartano 《Journal of solution chemistry》2008,37(2):183-201
Acid-base properties of some open-chain polyamines (ethylenediamine, diethylenetriamine, triethylenetetramine, spermine, tetraethylenepentamine
and pentaethylenehexamine) were studied at different ionic strengths in different aqueous ionic media at 25 °C. Measured were:
(i) the protonation constants of triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine from potentiometric
measurements [0 ≤I≤2.5 mol⋅L−1 in NaCl and (CH3)4NCl)]; and (ii) protonation enthalpies of ethylenediamine, diethylenetriamine, and spermine from calorimetric measurements
[NaCl: 0≤I≤1 mol⋅kg−1 for ethylenediamine, diethylenetriamine, 0 ≤I≤2 mol⋅kg−1 for spermine; (C2H5)4NI: 0≤I≤1 mol⋅kg−1; (CH3)4NCl: 0 ≤I≤2.5 mol⋅kg−1 only for diethylenetriamine]. Previously published protonation data for these polyamines in aqueous NaCl, (CH3)4NCl and (C2H5)4NI, were also examined. The general trends for the Gibbs energy and entropic contributions are, for ΔG: NaCl>(CH3)4NCl>(C2H5)4NI, and for TΔS: (C2H5)4NI>(CH3)4NCl>NaCl. This trend is more pronounced for the first protonation step. The dependences of these quantities on ionic strength
were modeled with the SIT (Specific ion Interaction Theory) equations, and differences found among the different media were
interpreted in terms of weak complex formation. 相似文献
16.
The effects of a substrate additive, H+ and solvents (water and acetone), on the micelle-catalyzed aquation of tris-(4,7-diphenyl-1, 10-phenanthroline)iron(II),
Fe(Ph2Phen)3
2+, have been investigated using#Triton X-100 micelles. The k0
vs. [TX-100] profiles at fixed [H2O] are structured, exhibiting maxima. Catalytic factors of 46.6–171.7 are observed for 5.56×10−2≤[H2O] 55.60×10−2 mol dm−3. On the other hand, at fixed [H+], the k0
vs. [TX-100] exhibit broad maxima. The aquation reaction is inhibited by H+ and catalytic factors decrease rapidly and exponentially from 422.5 to 20.9 for 0.20×10−3≤[H+]≤2.00×10−3 mol dm−3. The aquation is found to be faster (ca. 160–1200 fold) in acetone than in the aqueous medium depending on the added [H2O]. These observations are rationalized on the basis of a proposed modified lamellar structure for the Triton X-100 (TX-100)
micelles in which direct substitution of water molecules into the coordination sphere of the complex occurs. 相似文献
17.
The results of kinetic and equilibrium experiments with the set of reaction of proton abstraction from 4-nitrophenyl[bis(ethylsulphonyl)]methane
in acetonitrile are reported. Two strong organic bases are used: 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene
(MTBD).
The rates of proton transfer reaction have been measured by T-jump method in the presence of perchlorate of the appropriate
base as a common cation BH+ and supporting electrolyte-tetrabutylammonium perchlorate (TBAP) in the temperature range between 20–40°C are: k
H
=1.32×107−2.00×107 and 2.82×107−4.84×107 dm 3mol−1s−1 for MTBD and TBD respectively. The enthalpies of activation ΔH
MTBD
≠
=13.5 and ΔH
TBD
≠
=18.1 kJmol−1. The entropies of activation are negative: ΔS
MTBD
≠
=−62.3 and ΔS
TBD
≠
=−40.3 Jmol−1K−1.
The change of the absorbance of the anion of 4-nitrophenyl[bis9ethylsulphonyl)]methane at the temperature 25°C in the presence
of common cation BH+ gives the equilibrium constants K=705 and 906 M−1 for MTBD and TBD respectively.
Kinetic and equilibrium results are discussed. The possible mechanism of proton transfer reaction between 4-nitrophenyl[bis(ethylsulphonyl)]methane
and cyclic organic bases: MTBD and TBD in acetonitrile is proposed. 相似文献
18.
Manisha Singla Pavan Mathur Manisha Gupta M. S. Hundal 《Transition Metal Chemistry》2008,33(2):175-182
New bis-benzimidazole based diamide ligands N, N′-bis(2-methyl benzimidazolyl)-benzene-1,3-dicarboxamide [GBBA] and N-Octyl-N, N′-bis(2-methyl benzimidazolyl)-benzene- 1,3-dicarboxamide [O-GBBA] have been synthesized and utilized to prepare Cu(II) complexes
of general composition [Cu(GBBA)X
2] · nH2O and [Cu(O-GBBA)X2] · n H2O, where X is an exogenous anionic ligand (X = Cl−, NO3−, SCN−). The oxidation of electron deficient olefins has been investigated using [Cu(O-GBBA)X2] · nH2O as catalyst and TBHP as an alternate source of oxygen. The respective ketonic products have been isolated and characterized
by 1H-NMR. The complex [Cu(GBBA)(NO3)2] · 4H2O has been characterized structurally. It crystallizes in a monoclinic space group C2/c. Low temperature EPR spectra have been obtained for the complexes that shows gII > gI > 2.0024, indicating a tetragonal geometry in the solution state. The complexes display a quasi reversible redox wave due
to the Cu(II)/Cu(I) reduction process. The E1/2 values shift anodically as NO3− < SCN− < Cl−. 相似文献
19.
Süheyla Pura 《Journal of solution chemistry》2008,37(3):351-364
The equivalent conductivities of tris-(ethylenediamine)chromium complexes, [Cr(en)3]X3 (where X−= Cl−, Br−, I−; en = ethylenediamine) were measured as functions of temperature (278.15 to 328.15 K) and concentration [(1.948 ×10−4 to 10.728 ×10−4 mol⋅dm−3) and (2.282 ×10−4 to 11.246 ×10−4 mol⋅dm−3)] in N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMAC), respectively. Equivalent conductivity values for [Cr(en)3]X3 in DMF were found to be higher than those in DMAC. The conductivity data were analyzed with the Robinson-Stokes equations.
For [Cr(en)3]X3, the limiting equivalent ionic conductivities of [Cr(en)3]3+ and the ion-association constants (K
A) of the ion-pair between [Cr(en)3]3+ and the monovalent halide anions were determined in DMF and DMAC. The values of K
A for three complex salts in DMF were higher than those in DMAC. This can be ascribed to an increase of the ion-association
constants with a decrease of the relative permittivity of the solvents. The values of K
A at 298.15 K decreased in the order Cl−> Br−> I− in DMF and Cl−> I−> Br− in DMAC. The K
A
values for [Cr(en)3]Cl3 increased with increasing temperature in both DMF and DMAC. For [Cr(en)3]X3(X−= Br−, I−) in both solvents, this indicates increasing disorder occurs with increasing temperature.
Thermodynamic parameters (standard Gibbs energy, enthalpy and entropy changes) were determined from the temperature dependence
of K
A in DMF and DMAC. These parameters were inter-compared in their dependences on temperature and solvent. 相似文献
20.
Joanna Wiśniewska 《Transition Metal Chemistry》2007,32(6):811-815
The kinetics of the electron-transfer reactions between promazine (ptz) and [Co(en)2(H2O)2]3+ in CF3SO3H solution ([CoIII] = (2–6) × 10−3
m, [ptz] = 2.5 × 10−4
m, [H+] = 0.02 − 0.05 m, I = 0.1 m (H+, K+, CF3SO
3
−
), T = 288–308 K) and [Co(edta)]− in aqueous HCl ([CoIII] = (1 − 4) × 10−3
m, [ptz] = 1 × 10−4
m, [H+] = 0.1 − 0.5 m, I = 1.0 m (H+, Na+, Cl−), T = 313 − 333 K) were studied under the condition of excess CoIII using u.v.–vis. spectroscopy. The reactions produce a CoII species and a stable cationic radical. A linear dependence of the pseudo-first-order rate constant (k
obs) on [CoIII] with a non-zero intercept was established for both redox processes. The rate of reaction with the [Co(en)2(H2O)2]3+ ion was found to be independent of [H+]. In the case of the [Co(edta)]− ion, the k
obs dependence on [H+] was linear and the increasing [H+] accelerates the rate of the outer-sphere electron-transfer reaction. The activation parameters were calculated as follows:
ΔH
≠ = 105 ± 4 kJ mol−1, ΔS
≠ = 93 ± 11 J K−1mol−1 for [Co(en)2(H2O)2]3+; ΔH
≠ = 67 ± 9 kJ mol−1, ΔS
≠ = − 54 ± 28 J K−1mol−1 for [Co(edta)]−. 相似文献
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