Hydrophobic interaction of the aggregation of methane and benzene in (water + TBA)

The solubilities of o-xylene, m-xylene, and p-xylene in mixed solvents of t-butyl alcohol (TBA) and water at T=(283.15, 288.15, 293.15, and 298.15) K have been determined by spectrophotometry. The mole fractions of TBA in the mixed solvents are x=(0.000, 0.010, 0.020, 0.030, 0.040, 0.045, 0.050, 0.060, 0.080 and 0.100), respectively. The Gibbs energies of hydrophobic interaction (HI) for the aggregating process of two methane molecules with one benzene molecule in the mixed solvents have been studied, and the effects of solvent structure and solutes gathering state on the strength of HI have also been discussed.     

Solubilities of benzene, toluene and diphenyl in the t-butyl alcohol+water mixtures and hydrophobic interaction

The solubilitices of benzene, toluene and diphenyl in mixed solvents of t-butyl alcohol (TBA) and water at 283.15, 288.15, 293.15 and 298.15 K have been determined by spectrophotometry. The mole fraction of TBA [x (TBA)] in the mixed solvent are 0.000, 0.010, 0.020, 0.030, 0.040, 0.045, 0.050, 0.060, 0.080 and 0.100, respectively. The standard Gibbs energies of solution of benzene, toluene and diphenyl in the mixed solvent have also been calculated based on the solubility data. The hydrophobic interactions (HI) for the pairs of benzene-benzene, methane-benzene and methane-methane in the mixed solvent were calculated and discussed.     

2,3,5-三甲基氢醌的绿色合成工艺研究

以偏三甲苯(TMB)为原料,冰醋酸为溶剂,过氧化氢(50%)为氧化剂,通过直接氧化合成了2,3,5-三甲基氢醌(TMHQ);考察了反应温度、反应时间以及氧化剂和溶剂用量等对TMHQ收率的影响,确定了优化的氧化反应条件.结果表明,最优的氧化反应条件为:反应温度85℃,反应时间3h,TMB与冰醋酸的物质的量之比1∶12,TMB与过氧化氢的物质的量之比1∶11.     

Effect of Different Salts on the Solubilities of Benzene and Diphenyl in t—Butyl Alcohol—Water Mixture and Hydrophobic Interaction

The solubilities of benzene and diphenyl in mixed solvents of t-butyl alcohol (TBA) and water with different salts have been determined at T=298.15,303.15,308.15 and 313.15K.The molar fraction of TBA [x(TBA)] in mixed solvent is 0.045,and the molality of the salts (ms) in mixed solvents are 0.000,0.250,0.500,0.750 and 1.000mol/kg ,respectively.The standard Gibbs energies of solution of benzene and diphenyl in the mixed solvents have also been calculated based on the solubility data.The effects of different salts on the hydrophobic interaction (HI) for benzene-benzene pair in the systems were discussed.     

Reactions of 1-Trichloromethyl-2,4,6-trimethylbenzene with 2-Amino- and 2-Amino-5-bromopyridines

A new type of reaction has been discovered for trichloromethylarenes with pyridines. The reaction of 1-trichloromethyl-2,4,6-trimethylbenzene with 2-amino- and 2-amino-5-bromopyridines does not stop with formation of the pyridinium salt, but rather leads to unique amidines, namely, 1-[-(2-pyridylimino)-2,4,6-trimethylbenzyl]-2-pyridonimine and its 5-bromo derivative.     

Vibrational spectroscopy and DFT calculations of 1,3-dibromo-2,4,6-trimethylbenzene: Anharmonicity,coupling and methyl group tunneling

The Raman, IR and INS spectra of 1,3-dibromo-2,4,6-trimethylbenzene (DBMH) were recorded in the 80–3200 cm⁻¹ range. The molecular conformation and vibrational spectra of DBMH were computed at the MPW1PW91/LANL2DZ level. Except for the methyl 2 environment, the agreement between the DFT calculations and the neutron diffraction structure is almost perfect (deviations < 0.01 Å for bond lengths, <0.2° for angles). The frequencies of the internal modes of vibration were calculated with the harmonic and anharmonic approximations; the later method yields results that are in remarkable agreement with the spectroscopic data, resulting in a confident assignment of the vibrational bands. Thus, no scaling is necessary. The coupling, in phase or anti-phase, of the motions of symmetrical CBr and CMe bonds is highlighted. Our DFT calculations suggest that the torsion of methyl groups 4 and 6 is hindered in deep wells, whereas methyl group 2 is a quasi-free rotor. The failure of the calculations to determine the frequencies of the methyl torsional modes is explained as follows: DFT does not consider the methyl spins and assumes localization of the protons, whereas the methyl groups must be treated as quantum rotors.     

合成皂石及其交联物在偏三甲苯歧化反应中的催化行为

以羟基铝低聚物与其交联制得柱撑皂石,并在偏三甲苯歧化反应中考察了它们的催化性能.结果表明,催化活性随柱撑皂石表面酸量增加而增加;四甲苯中均四甲苯和二甲苯中邻二甲苯的百分含量皆高于热力学平衡值.催化特性与柱撑皂石的柱密度相关.     

Molecular and Crystal Structure of 1,3,5- Tris(benzimidazol- 1-ylmethyl)-2,4,6-Trimethylbenzene

INTRODUCTIONCrystal engineering and supramolecular chemistry aimed at developing systems to perform optical, magnetic and electronic functions as well as intercalation systems for ion- or molecule-exchange and catalytic properties are some of the most attractive research areas in present years, and much progress has been achieved in both theoretical studies and their applications as new materials[1]. One of the most remarkable development in crystal engineering may be that it is possible t…     

均三甲苯的合成

介绍了由丙酮、偏三甲苯及连三甲苯合成均三甲苯的反应。参考文献15篇。     

Synthesis and Crystal Structure of 1,4,Bis-（benztriazol-1-ylmethyl）-2,3,5,6-tetramethylbenzene

1 INTRODUCTION Crystal engineering of supramolecular arrays hasbeen one of the most important areas of researchwith wide implications for the rational design offunctional materials[1]. Two major directions[2] havebeen actively pursued: the construction of organicnetworks consolidated by directional non-covalentinteractions[3] and that of coordination polymers sus-tained by coordinated covalent bonds[4, . One of the 5]most remarkable developm…     

Enthalpies of transfer of 2-methyl-2-propanol from water to mixtures of water with methanol,ethanol and 1,4-dioxane

The enthalpies of transfer of 2-methyl-2-propanol (TBA) from water to mixtures of water with methanol, ethanol and 1,4-dioxane have been measured. The data are considered in terms of recently developed theory, and it is found that the enthalpies of transfer can be reproduced quantitatively over most of the composition range in each solvent system. The parameters recovered from the analyses indicate that the net effect of TBA on the solvent structure is a breaking of solvent-solvent bonds and that TBA is preferentially hydrated in the aqueous alcohol systems, but randomly solvated in the water+1,4-dioxane system. It is also found that the model parameters for TBA solvation in the alcohol systems are independent of the alcohol.     

Chlorination and oxidation products formed from 1,2,4-trimethylbenzene in aqueous solution under the action of chlorine dioxide

Products of the reaction of 1,2,4-trimethylbenzene with chlorine dioxide in aqueous solution were studied. A scheme of 1,2,4-trimethylbenzene transformations was suggested. The influence exerted on the number of the reaction products by the ClO₂ dosage and time of its contact with the substrate was examined.     

An efficient and facile one-pot synthesis of structurally unique 2,4,6-tris(arylchalcogeno)-1,3,5-triazine and 1,3,5-tris(arylchalcogeno)-2,4,6-trimethylbenzene

An efficient one-pot synthesis of a novel class of 2,4,6-tris(arylchalcogeno)-1,3,5-triazine (sulfur, selenium and tellurium) and 1,3,5-tris(arylchalcogeno)-2,4,6-trimethylbenzene (sulfur and selenium)-containing ligands has been developed based on the reaction of 2,4,6-trichloro-1,3,5-triazine and 1,3,5-tris(bromomethyl)-2,4,6-trimethylbenzene with the corresponding arylchalcogenide anions generated in aqueous tetrahydrofuran.     

Transfer hydrogenation of ketones catalyzed by ruthenium complexes

Oxidation of 1,3,5- and 1,2,4-trimethylbenzenes using heteropoly vanadomolybdate as catalyst in the presence of hydrogen peroxide under homogeneous conditions has been investigated. Phenol formation in the case of 1,2,4-trimethylbenzene and only side chain oxidation in the case 1,3,5-trimethylbenzene were observed. This behavior is explained in terms of the charge densities on different centers of both substrate molecules calculated by the MNDO method.     

Regioisomerism in the Ritter reaction. 1. Synthesis of 3,3,5,6,7-, 3,3,6,7,8-, 3,3,5,7,8-, and 3,3,5,6,8-pentamethyl-3,4-dihydroisoquinolines from 1,2,3- and 1,2,4-trimethylbenzenes

Reactions of 1,2,3- or 1,2,4-trimethylbenzene with isobutyraldehyde and ethyl cyanoacetate (ECA) or reactions of the corresponding 1-aryl-2-methylpropan-1-ols with ECA afforded isomeric 3,3,5,6,7-, 3,3,6,7,8-, 3,3,5,7,8-, and 3,3,5,6,8-pentamethyl-3,4-dihydroisoquinolines. Isomerization is explained as the ring opening of a spiran intermediate in two possible ways followed by the Jacobsen rearrangement.     

Temperature-dependent rate constants for the gas-phase reactions of OH radicals with 1,3,5-trimethylbenzene, triethyl phosphate, and a series of alkylphosphonates

Rate constants for the reactions of OH radicals with dimethyl methylphosphonate [DMMP, (CH3O)2P(O)CH3], dimethyl ethylphosphonate [DMEP, (CH3O)2P(O)C2H5], diethyl methylphosphonate [DEMP, (C2H5O)2P(O)CH3], diethyl ethylphosphonate [DEEP, (C2H5O)2P(O)C2H5], triethyl phosphate [TEP, (C2H5O)3PO] and 1,3,5-trimethylbenzene have been measured over the temperature range 278-348 K at atmospheric pressure of air using a relative rate method. alpha-Pinene (for DEMP, DEEP, TEP and 1,3,5-trimethylbenzene) and di-n-butyl ether (for DMMP and DMEP) were used as the reference compounds, and rate constants for the reaction of OH radicals with di-n-butyl ether were also measured over the same temperature range using alpha-pinene and n-decane as the reference compounds. The Arrhenius expressions obtained for these OH radical reactions (in cm3 molecule(-1) s(-1) units) are 8.00 x 10(-14)e(1470+/-132)/T for DMMP (296-348 K), 9.76 x 10(-14)e(1520+/-14)/T for DMEP (296-348 K), 4.20 x 10(-13)e(1456+/-227)/T for DEMP (296-348 K), 6.46 x 10(-13)e(1339+/-376)/T for DEEP (296-348 K), 4.29 x 10(-13)e(1428+/-219)/T for TEP (296-347 K), and 4.40 x 10(-12)e(738+/-176)/T for 1,3,5-trimethylbenzene (278-347 K), where the indicated errors are two least-squares standard deviations and do not include the uncertainties in the rate constants for the reference compounds. The measured rate constants for di-n-butyl ether are in good agreement with literature data over the temperature range studied (278-348 K).     

Product analysis of the reaction of OH with benzene,toluene, and 1,3,5-trimethylbenzene at 300 K

Products of the reaction of OH with benzene, toluene, and 1,3,5-trimethylbenzene have been identified in crossed molecular beam experiments conducted at 300 K. Ionization potentials of the most intense products were also measured.     

Solubility of ethane int-butanol + water mixtures and a hydrophobic interaction study

The solubilities of ethane int-butanol (TBA) and water mixtures have been determined at 10, 15, and 20°C and pressures up to 3.1 MPa. Thermodynamic properties have also been calculated based on the measured solubility data and the hydrophobic interaction for the methane-methane pair interaction in the mixed solvent is discussed.     

Catalytic properties of polyvanadomolybdic acids in oxidation of 1,2,4-trimethylbenzene by peracetic acid

Polyvanadomolybdic acids catalyze the process of peracid oxidation of 1,2,4-trimethylbenzene. The selectivity with respect to 2,3,5-trimethyl-1,4-benzoquinone increases with increasing degree of replacement of vanadium atoms in the PVMA by molybdenum; this is related to increased stability of the intermediate peroxides of the heteropolyvanadates.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 1967–1969, September, 1989.     

Synthesis of amphiphilic diblock copolymers poly[2-(<Emphasis Type="Italic">N</Emphasis>, <Emphasis Type="Italic">N</Emphasis>-dimethylamino)ethyl methacrylate]-<Emphasis Type="Italic">b</Emphasis>-poly(stearyl methacrylate) and their self-assembly in mixed solvent

Amphiphilic diblock copolymers consisting of 2-(N, N-dimethylamino)ethyl methacrylate (DMAEMA, abbreviated as DMA) and stearyl methacrylate (SMA) with different degrees of polymerization and compositions were prepared by reversible addition–fragmentation chain transfer (RAFT) copolymerization. The composition and chemical structures of (co)polymers were confirmed by the measurements of ¹H NMR spectroscopy and gel permeation chromatography (GPC). The self-aggregating structures of amphiphilic diblock copolymers with the concentration of 0.1~0.3 wt.% in THF/water mixed solvent was investigated by transmission electron microscopy (TEM) and dynamic light scattering (DLS). It was found that both the morphologies and aggregating particle size resulted from the amphiphilic diblock copolymers depended on the variation of pH values, the lengths of the hydrophobic PSMA chains, and the weight ratio of THF/water mixed solvent.