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1.
The energies of combustion for 2-nitrobenzenesulfonamide (cr), 3-nitrobenzenesulfonamide (cr), and 4-nitrobenzenesulfonamide (cr) were determined using a recently described rotating-bomb combustion calorimeter. The condensed phase molar energies of combustion obtained were ?(3479.2 ± 1.0) kJ · mol?1 for 2-nitrobenzenesulfonamide (cr), ?(3454.2 ± 1.1) kJ · mol-1 for 3-nitrobenzenesulfonamide (cr), and ?(3450.1 ± 1.9) kJ · mol-1 for 4-nitrobenzenesulfonamide (cr). From these combustion energy values, the standard molar enthalpies of formation in the condensed phase were obtained as: ?(341.3 ± 1.3) kJ · mol?1, ?(366.3 ± 1.3) kJ · mol?1, and ?(370.4 ± 2.1) kJ · mol?1, respectively. Polyethene bags were used as an auxiliary material in the combustion experiments. The heat capacities and purities of the compounds were determined using a differential scanning calorimeter. 相似文献
2.
Manuel A.V. Ribeiro da Silva Luísa M.P.F. Amaral 《The Journal of chemical thermodynamics》2009,41(1):26-29
The standard (p° = 0.1 MPa) molar energies of combustion of 2-furancarbonitrile, 2-acetylfuran, and 3-furaldehyde were measured by static bomb combustion calorimetry; the Calvet high-temperature microcalorimetry was used to measure the enthalpies of vaporization of these liquid compounds. The standard molar enthalpies of formation of the three compounds, in the gaseous phase, at T = 298.15 K, have been derived from the corresponding standard molar enthalpies of formation in the liquid phase and the standard molar enthalpies of phase transition, as (106.8 ± 1.1) kJ · mol?1, ?(207.4 ± 1.3) kJ · mol?1, and ?(151.9 ± 1.1) kJ · mol?1, for 2-furancarbonitrile, 2-acetylfuran, and 3-furaldehyde, respectively.Standard molar enthalpies of formation are discussed in terms of the isomerization ortho meta. Enthalpic increment values of the introduction of the functional groups –CN, –CHO, and –COCH3 were also compared with some other heterocycles; i.e. thiophene and pyridine. 相似文献
3.
Two pure hydrated lead borates, Pb(BO2)2·H2O and PbB4O7·4H2O, have been characterized by XRD, FT-IR, DTA-TG techniques and chemical analysis. The molar enthalpies of solution of Pb(BO2)2·H2O and PbB4O7·4H2O in 1 mol dm?3 HNO3(aq) were measured to be (?35.00 ± 0.18) kJ mol?1 and (35.37 ± 0.14) kJ mol?1, respectively. The molar enthalpy of solution of H3BO3(s) in 1 mol dm?3 HNO3(aq) was measured to be (21.19 ± 0.18) kJ mol?1. The molar enthalpy of solution of PbO(s) in (HNO3 + H3BO3)(aq) was measured to be ?(61.84 ± 0.10) kJ mol?1. From these data and with incorporation of the enthalpies of formation of PbO(s), H3BO3(s) and H2O(l), the standard molar enthalpies of formation of ?(1820.5 ± 1.8) kJ mol?1 for Pb(BO2)2·H2O and ?(4038.1 ± 3.4) kJ mol?1 for PbB4O7·4H2O were obtained on the basis of the appropriate thermochemical cycles. 相似文献
4.
M. Agostinha R. Matos Clara C.S. Sousa Victor M.F. Morais 《The Journal of chemical thermodynamics》2009,41(1):69-73
The standard (p° = 0.1 MPa) molar energies of combustion in oxygen, at T = 298.15 K, of 5-, 6- and 7-methoxy-α-tetralone were measured by static bomb calorimetry. The values of the standard molar enthalpies of sublimation were obtained by Calvet microcalorimetry and corrected to T = 298.15 K. Combining these results, the standard molar enthalpies of formation of the compounds, in the gas phase, at T = 298.15 K, have been calculated, 5-methoxy-α-tetralone -(244.8 ± 1.9) kJ · mol?1, 6-methoxy-α-tetralone ?(243.0 ± 2.8) kJ · mol?1 and 7-methoxy-α-tetralone ?(242.3 ± 2.6) kJ · mol?1.Additionally, high-level density functional theory calculations using the B3LYP hybrid exchange–correlation energy functional with extended basis sets and more accurate correlated computational techniques of the MCCM/3 suite have been performed for the compounds. The agreement between experiment and theory gives confidence to estimate the enthalpy of formation of 8-methoxy-α-tetralone. Similar calculations were done for the 5-, 6-, 7- and 8-methoxy-β-tetralone, for which experimental work was not done. 相似文献
5.
M. Agostinha R. Matos Margarida S. Miranda Victor M.F. Morais 《The Journal of chemical thermodynamics》2008,40(4):625-631
The standard (p° = 0.1 MPa) molar enthalpies of combustion and sublimation of 3,4,5-trimethoxyphenol were measured, respectively, by static bomb combustion calorimetry in oxygen atmosphere and by Calvet microcalorimetry. From these measurements, the standard molar enthalpy of formation in both the crystalline and gaseous phase, at T = 298.15 K, were derived: ?(643.4 ± 1.9) kJ · mol?1 and ?(518.1 ± 3.6) kJ · mol?1, respectively. Density functional theory calculations for this compound and respective phenoxyl radical and phenoxide anion were also performed using the B3LYP functional and extended basis sets, which allowed the theoretical estimation of the gaseous phase standard molar enthalpy of formation through the use of isodesmic reactions and the calculation of the homolytic and heterolytic O–H bond dissociation energies. There is good agreement between the calculated and experimental enthalpy of formation. Substituent effects on the homolytic and heterolytic O–H bond dissociation energies have been analysed. 相似文献
6.
Manuel A.V. Ribeiro da Silva Joana I.T.A. Cabral 《The Journal of chemical thermodynamics》2008,40(5):829-835
The standard (p° = 0.1 MPa) molar enthalpies of combustion of 1-(2H)-phthalazinone and phthalhydrazide, both in the solid phase, were measured at T = 298.15 K by static bomb calorimetry. Further, the standard molar enthalpies of sublimation, at T = 298.15 K, of these two phthalazine derivatives were derived from the Knudsen effusion technique. The combustion calorimetry results together with those obtained from the Knudsen effusion technique, were used to derive the standard molar enthalpies of formation, at T = 298.15 K, in the gaseous phase for 1-(2H)-phthalazinone and phthalhydrazide, respectively as, (79.1 ± 1.8) kJ · mol?1 and ?(107.4 ± 2.4) kJ · mol?1. 相似文献
7.
M. Agostinha R. Matos Clara C.S. Sousa Victor M.F. Morais 《The Journal of chemical thermodynamics》2008,40(10):1485-1489
The standard molar energies of combustion, at T = 298.15 K, of crystalline 1,4-benzodioxan-2-carboxylic acid and 1,4-benzodioxan-2-hydroxymethyl were measured by static bomb calorimetry in an oxygen atmosphere. The standard molar enthalpies of sublimation, at T = 298.15 K, were obtained by Calvet microcalorimetry. These values were used to derive the standard molar enthalpies of formation of the compounds in the gas phase at T = 298.15 K: 1,4-benzodioxan-2-carboxylic acid ?(547.7 ± 3.0) kJ · mol?1 and 1,4-benzodioxan-2-hydroxymethyl ?(374.2 ± 2.3) kJ · mol?1.In addition, density functional theory calculations using the B3LYP hybrid exchange–correlation energy functional with extended basis sets, 6-311G7 and cc-pVTZ, have been performed for the compounds studied. We have also tested two more accurate computational procedures involving multiple levels of electron structure theory in order to get reliable estimates of the thermochemical parameters of the compounds studied. The agreement between experiment and theory gives confidence to estimate the enthalpies of formation of other 2-R derivatives of 1,4-benzodioxan (R = –CH2COOH, –OH, –COCH3, –CHO, –CH3, –CN, and –NO2). 相似文献
8.
《The Journal of chemical thermodynamics》2002,34(11):1777-1785
The molar enthalpies of reaction of metallic barium with 0.047 mol·dm−3 HClO4 as well as the molar enthalpies of dissolution of BaCl2 in 1.01 mol·dm−3 HCl and in water have been measured at T=298.15 K in a sealed swinging calorimeter with an isothermal jacket. From these results the standard molar enthalpy of formation of the barium ion in an aqueous solution at infinite dilution, as well as the enthalpies of formation of barium chloride and barium perchlorate, are calculated to be: ΔfH0m(Ba2+,aq)=−(535.83±1.25) kJ · mol−1; ΔfH0m(BaCl2,cr)=−(855.66±1.28) kJ · mol−1; and ΔfH0m(BaClO4,cr)=−(796.26±1.35) kJ · mol−1. The results obtained are discussed and compared with previous experimental values. 相似文献
9.
The standard (po = 0.1 MPa) molar enthalpies of formation, in the gaseous phase, at the reference temperature of 298.15 K, of 2-amino-4-methylpyrimidine ((98.1 ± 1.6) kJ · mol−1), 2-amino-4,6-dimethylpyrimidine ((55.9 ± 1.8) kJ · mol−1) and 4-amino-2,6-dimethylpyrimidine ((60.1 ± 1.8) kJ · mol−1) were calculated from the enthalpies of formation, in the crystalline phase, and enthalpies of sublimation, derived, respectively, from static bomb combustion calorimetry and Knudsen effusion technique results. In order to quantify the resonance effects arising from the substitution on the pyrimidine ring, hypothetical isodesmic reactions were used to analyze the experimental gaseous-phase enthalpies of formation. The aromaticity of benzene, pyridine, pyrimidine and the substituted pyrimidines was investigated in terms of magnetic (NICS), geometric (HOMA), electronic (Shannon aromaticity, QTAIMs ring critical point properties and HOMO–LUMO gap), reactive (hardness), vibrational (Kekulé mode) and spectroscopic (UV–Vis) properties. 相似文献
10.
Maria das Dores M.C. Ribeiro da Silva Manuel A.V. Ribeiro da Silva Vera L.S. Freitas Maria Victoria Roux Pilar Jiménez Juan Z. Dávalos Pilar Cabildo Rosa M. Claramunt Elena Pinilla M. Rosario Torres José Elguero 《The Journal of chemical thermodynamics》2010,42(4):536-544
Thermochemical and thermophysical studies have been carried out for crystalline 3,4,4′-trichlorocarbanilide. The standard (p° = 0.1 MPa) molar enthalpy of formation, at T = 298.15 K, for the crystalline 3,4,4′-trichlorocarbanilide (TCC) was experimentally determined using rotating-bomb combustion calorimetry, as ?(234.6 ± 8.3) kJ · mol?1. The standard enthalpy of sublimation, at the reference temperature of 298.15 K, was measured by the vacuum drop microcalorimetric technique, using a High Temperature Calvet Microcalorimeter as (182.1 ± 1.7) kJ · mol?1. These two thermochemical parameters yielded the standard molar enthalpy of formation of the studied compound, in the gaseous phase, at T = 298.15 K, as ?(52.5 ± 8.5) kJ · mol?1. This parameter was also calculated by computational thermochemistry at M05-2X/6-311++G7 and B3LYP/6-311++G(3df, 2p) levels, with a deviation less than 4.5 kJ · mol?1 from experimental value. Moreover, the thermophysical study was made by differential scanning calorimetry, DSC, over the temperature interval between T = 263 K and its onset fusion temperature, T = (527.5 ± 0.4) K. A solid–solid phase transition was found at T = (428 ± 1) K, with the enthalpy of transition of (6.1 ± 0.1) kJ · mol?1. The X-ray crystal structure of TCC was determined and the three-centred N–H?OC hydrogen bonds present analyzed. 相似文献
11.
Drew Gorman-Lewis Jeremy B. Fein Peter C. Burns Jennifer E.S. Szymanowski Jenalee Converse 《The Journal of chemical thermodynamics》2008,40(6):980-990
The mobility of uranium under oxidizing conditions can only be modeled if the thermodynamic stabilities of the secondary uranyl minerals are known. Toward this end, we synthesized metaschoepite (UO3(H2O)2), becquerelite (Ca(UO2)6O4(OH)6(H2O)8), compreignacite (K2(UO2)6O4(OH)6(H2O)7), sodium compreignacite (Na2(UO2)6O4(OH)6(H2O)7), and clarkeite (Na(UO2)O(OH)) and performed solubility measurements from both undersaturation and supersaturation under controlled-pH conditions. The solubility measurements rigorously constrain the values of the solubility products for these synthetic phases, and consequently the standard-state Gibbs free energies of formation of the phases. The calculated lg solubility product values (lg Ksp), with associated 1σ uncertainties, for metaschoepite, becquerelite, compreignacite, sodium compreignacite, and clarkeite are (5.6 ?0.2/+0.1), (40.5 ?1.4/+0.2), (35.8 ?0.5/+0.3), (39.4 ?1.1/+0.7), and (9.4 ?0.9/+0.6), respectively. The standard-state Gibbs free energies of formation, with their 2σ uncertainties, for these same phases are (?1632.2 ± 7.4) kJ · mol?1, (?10305.6 ± 26.5) kJ · mol?1, (?10107.3 ± 21.8) kJ · mol?1, (?10045.6 ±24.5) kJ · mol?1, and (?1635.1 ± 23.4) kJ · mol?1, respectively. Combining our data with previously measured standard-state enthalpies of formation for metaschoepite, becquerelite, sodium compreignacite, and clarkeite yields calculated standard-state entropies of formation, with associated 2σ uncertainties, of (?532.5 ± 8.1) J · mol?1 · K?1, (?3634.5 ± 29.7) J · mol?1 · K?1, ( ?2987.6 ± 28.5) J · mol?1 · K?1, and (?300.5 ± 23.9) J · mol?1 · K?1, respectively. The measurements and associated calculated thermodynamic properties from this study not only describe the stability and solubility at T = 298 K, but also can be used in predictions of uranium mobility through extrapolation of these properties to temperatures and pressures of geologic and environmental interest. 相似文献
12.
Mohd Zul Helmi Rozaini Peter Brimblecombe 《The Journal of chemical thermodynamics》2009,41(9):980-983
The solubility measurements of sodium dicarboxylate salts; sodium oxalate, malonate, succinate, glutarate, and adipate in water at temperatures from (278.15 to 358.15 K) were determined. The molar enthalpies of solution at T = 298.15 K were derived: ΔsolHm (m = 2.11 mol · kg?1) = 13.86 kJ · mol?1 for sodium oxalate; ΔsolHm (m = 3.99 mol · kg?1) = 14.83 kJ · mol?1 for sodium malonate; ΔsolHm (m = 2.45 mol · kg?1) = 14.83 kJ · mol?1 for sodium succinate; ΔsolHm (m = 4.53 mol · kg?1) = 16.55 kJ · mol?1 for sodium glutarate, and ΔsolHm (m = 3.52 mol · kg?1) = 15.70 kJ · mol?1 for sodium adipate. The solubility value exhibits a prominent odd–even effect with respect to terms with odd number of sodium dicarboxylate carbon numbers showing much higher solubility. This odd–even effect may have implications for the relative abundance of these compounds in industrial applications and also in the atmospheric aerosols. 相似文献
13.
Clara C.S. Sousa M. Agostinha R. Matos Victor M.F. Morais 《The Journal of chemical thermodynamics》2011,43(8):1159-1163
In this work, we have determined the experimental standard molar enthalpies of formation, in the gas phase, of 2,6-dimethyl-4-pyrone ?(261.5 ± 2.6) kJ · mol?1 and 2-ethyl-3-hydroxy-4-pyrone ?(420.9 ± 2.8) kJ · mol?1. These values were obtained by combining the standard molar enthalpy of formation in the condensed phase, derived from combustion experiments in oxygen, at T = 298.15 K, in a static bomb calorimeter, with the standard molar enthalpy of sublimation, at T = 298.15 K, obtained by Calvet microcalorimetry. Additionally, high-level density functional theory calculations using the B3LYP hybrid exchange-correlation energy functional with extended basis sets have been performed for these two compounds. Good agreement was obtained between the experimental and computational results. Using the same methodology, we calculated the standard molar enthalpy of formation of gaseous 2-methyl-3-hydroxy-4-pyrone. 相似文献
14.
《The Journal of chemical thermodynamics》2003,35(9):1403-1412
The strain energy of phenanthrene was derived to be (4.9 ± 2.8) kJ · mol−1, on the basis of the latest standard enthalpies of formation of polycyclic aromatic hydrocarbons. This strain energy agrees well with those estimated from a semi-empirical calculation and from the basicity in hydrogen fluoride solution. The calculation again confirmed the standard enthalpy of formation of phenanthrene, ΔfH0(g)=(201.7±2.9) kJ · mol−1 at T=298.15 K, which was determined by Nagano (J. Chem. Thermodyn. 34 (2002) 377–383). The coupling constant J4,5 in 1H-n.m.r. spectrum of phenanthrene in CDCl3 solution was determined to be 0.55 Hz, which indicates no significant through-space coupling between the 4- and 5-hydrogens. 相似文献
15.
《The Journal of chemical thermodynamics》2006,38(2):152-157
Vapour pressures of water over saturated solutions of cesium chloride, cesium bromide, cesium nitrate, cesium sulfate, cesium formate, and cesium oxalate were determined as a function of temperature. These vapour pressures were used to evaluate the water activities, osmotic coefficients and molar enthalpies of vapourization. Molar enthalpies of solution of cesium chloride, ΔsolHm(T = 295.73 K; m = 0.0622 mol · kg−1) = (17.83 ± 0.50) kJ · mol−1; cesium bromide, ΔsolHm(T = 293.99 K; m = 0.0238 mol · kg−1) = (26.91 ± 0.59) kJ · mol−1; cesium nitrate, ΔsolHm(T = 294.68 K; m = 0.0258 mol · kg−1) = (37.1 ± 2.3) kJ · mol−1; cesium sulfate, ΔsolHm(T = 296.43 K; m = 0.0284 mol · kg−1) = (16.94 ± 0.43) kJ · mol−1; cesium formate, ΔsolHm(T = 295.64 K; m = 0.0283 mol · kg−1) = (11.10 ± 0.26) kJ · mol−1 and ΔsolHm(T = 292.64 K; m = 0.0577 mol · kg−1) = (11.56 ± 0.56) kJ · mol−1; and cesium oxalate, ΔsolHm(T = 291.34 K; m = 0.0143 mol · kg−1) = (22.07 ± 0.16) kJ · mol−1 were determined calorimetrically. The purity of the chemicals was generally greater than 0.99 mass fraction, except for HCOOCs and (COOCs)2 where purities were approximately 0.95 and 0.97 mass fraction, respectively. The uncertainties are one standard deviations. 相似文献
16.
The standard molar enthalpies of combustion of 2-aminobenzothiazole (2AB), 2-amino-4-methyl-benzothiazole (2A4MB), and 2-amino-6-methyl-benzothiazole (2A6MB) were determined in the crystalline phase at T = 298.15 K using a rotating-bomb combustion calorimeter. The molar energies of combustion of these compounds were found to be: (−4273.6 ± 0.9), (−4896.9 ± 1.1), and (−4906.9 ± 1.2) kJ · mol−1, respectively. From these values, the corresponding standard molar enthalpies of formation in the solid phase were obtained as: (59.55 ± 1.28), (2.71 ± 1.50), and (13.53 ± 1.53) kJ · mol−1, respectively. The enthalpies of formation in the gas phase were determined using the experimental enthalpies of formation in the solid phase and predicted values of the enthalpies of sublimation. Additionally, the enthalpies of formation in the gas phase were calculated by means of the Gausian-4 theory, using several gas-phase working reactions, and were compared with those found using the predicted enthalpies of sublimation. 相似文献
17.
Hydroboration reactions of 4-octene with HBBr2 · SMe2, HBCl2 · SMe2 and H2BBr · SMe2 in CH2Cl2 were studied as function of concentration and temperature and compared with those of 1-octene. On average, hydroboration with dihaloborane proceeded 16 times slower for 4-octene than for 1-octene. In the case of the reactions with the monohaloborane, this factor is halved. This can be explained by the difference in the relative rates of dissociates of Me2S from the dihaloborane and a monohaloborane complex, respectively. The reactions involving H2BBr · SMe2 also exhibited a k?2 value, an indication of the presence of a parallel reaction, most likely a rearrangement process facilitating isomerization by way of a π-complex. The moderate ΔH≠ values accompanied by small ΔS≠ values (94 ± 4 kJ mol?1, ?3 ± 13 J K?1 mol?1 for HBBr2 · SMe2; 93 ± 1 kJ mol?1, ?17 ± 4 J K?1 mol?1 for HBCl2 · SMe2 and in the case of H2BBr · SMe2, 90 ± 13 kJ mol?1, +12 ± 44 J K?1 mol?1 and 83 ± 13 kJ mol?1, ?24 ± 45 J K?1 mol?1, respectively, for the k2 and k?2 processes) imply a process that is dissociatively dominated, with the overall mode of activation being interchange dissociative (Id). 相似文献
18.
The (solid + liquid) phase equilibria of the ternary systems (CsBr + LnBr3 + H2O) (Ln = Pr, Nd, Sm) at T = 298.2 K were studied by the isothermal solubility method. The solid phases formed in the systems were determined by the Schreinemakers wet residues technique, and the corresponding phase diagrams were constructed based on the measured data. Each of the phase diagrams, with two invariant points, three univariant curves, and three crystallization regions corresponding to CsBr, Cs2LnBr5·10H2O and LnBr3·nH2O (n = 6, 7), respectively, belongs to the same category. The new solid phase compounds Cs2LnBr5·10H2O are incongruently soluble in water, and they were characterized by chemical analysis, XRD and TG-DTG techniques. The standard molar enthalpies of solution of Cs2PrBr5·10H2O, Cs2NdBr5·10H2O and Cs2SmBr5·10H2O in water were measured to be (52.49 ± 0.48) kJ · mol−1, (49.64 ± 0.49) kJ · mol−1 and (50.17 ± 0.48) kJ · mol−1 by microcalorimetry under the condition of infinite dilution, respectively, and their standard molar enthalpies of formation were determined as being −(4739.7 ± 1.4) kJ · mol−1, −(4728.4 ± 1.4) kJ · mol−1 and −(4724.4 ± 1.4) kJ · mol−1, respectively. The fluorescence excitation and emission spectra of Cs2PrBr5·10H2O, Cs2NdBr5·10H2O and Cs2SmBr5·10H2O were measured. The results show that the upconversion spectra of the three new solid phase compounds all exhibit a peak at 524 nm when excited at 785 nm. 相似文献
19.
《The Journal of chemical thermodynamics》2003,35(5):803-811
The enthalpies of combustion and of sublimation, respectively, of the three isomeric nitrobenzonitriles have been measured: o-, {(−3456.3±2.9), (88.1±1.4)} kJ·mol−1; m-, {(−3442.8±3.3), (92.8±0.3)} kJ·mol−1; p-, {(−3448.2±3.6), (91.1±1.3)} kJ·mol−1. In turn, from these values, the standard molar enthalpies of formation for the condensed and gaseous state, respectively, have been derived: o-, {(130.1±3.1), (218.2±3.4)} kJ·mol−1; m-, {(116.5±3.5), (209.3±3.5)} kJ·mol−1; p-, {(122.0±3.8), (213.1±4.0)} kJ·mol−1. Destabilization energies associated with the presence of the two electron-withdrawing groups have been determined, for o-, m-, and p-nitrobenzonitrile, {(17.6±4.1), (8.7±4.2), and (12.5±4.6)} kJ·mol−1, respectively, and are consistent with those obtained for the corresponding sets of isomeric methyl benzenedicarboxylates, dicyanobenzenes, dinitrobenzenes, and (neutral and ionized) nitrobenzoic acids. 相似文献
20.
The standard (p° = 0.1 MPa) molar enthalpies of formation of 3-acetylbenzonitrile and benzoylacetonitrile, in the crystalline phase, were derived from the respective standard massic energies of combustion measured by static bomb combustion calorimetry, in oxygen, at T = 298.15 K. The standard molar enthalpies of sublimation, at T = 298.15 K, were measured by Calvet microcalorimetry. From the above experimentally determined enthalpic parameters, the standard molar enthalpies of formation in the gaseous phase, at T = 298.15 K, are found to be: (52.4 ± 2.1) kJ · mol−1 and (74.8 ± 2.5) kJ · mol−1 for 3-acetylbenzonitrile and benzoylacetonitrile, respectively.Molecular structures were computed using highly accurate ab initio techniques. Standard molar enthalpies of formation of the experimentally studied compounds were derived using an appropriate set of working reactions. Very good agreement between the calculated and the experimental values was obtained, so the calculations were extended to the estimates of the standard molar enthalpies of formation of 2- and 4-acetylbenzonitriles whose study was not performed experimentally.Our results were further interpreted and rationalized in terms of the enthalpic stability and compared to other relevant disubstituted benzenes. 相似文献