Physical properties of benzene

Benzene is a typical nonpolar compound that, like other nonpolar compounds, has a low solubility in water. It has a characteristic odor which most people find unpleasant. It was widely used in academic labs as a solvent, but that use has been largely discontinued since it was found that benzene may be carcinogenic. 

Just what makes a substance, such as benzene, aromatic We know that benzene is more stable than expected. The increased stability of benzene is due to resonance having a stabilizing influence. Following are the requirements for a species to be aromatic  

This means that an sp3 atom cannot be part of an aromatic system, o The ring system must have a Hiickel number of -electrons. 

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Calculate Apj, ATf, ATj, and n for solutions which are 1% by weight in benzene of solutes for which M = 10 and 10 . Assume that these solutions are adequately described by dilute ideal solution expressions. Consult a handbook for the physical properties of benzene. Comment on the significance of the results with respect to the feasibility of these various methods for the determination of M for solutes of high and low molecular weight. 

Physical Properties of Benzene and Its Derivatives 742 16-15 Spectroscopy of Aromatic Compounds 743 EssentialTerms 746 Study Problems 748... 

The thickness of the vessel walls will depend on the design pressure. If the reagents have the physical properties of benzene their vapor pressure will be appreciable and the design pressure P psia) should exceed this by 25 psia for safety. If the minimum design pressure is 50 psia, we have... 

Electrophilic substitution This is not meant to be a definitive account of aromaticity. It will suffice if we consider only one tj of chemical reaction and two of the physical properties of benzene to demonstrate the point. 

The physical properties of benzene and other aromatic hydrocarbons are similar to those of alkanes and alkenes. They are nonpolar and thns insoluble in water. This hydrophobic characteristic plays an important role in the chemistry of some proteins (Chapter 9). 

The physical properties of benzene and its derivatives are quite similar to those of other hydrocarbons. The compounds are nonpolar, insoluble in polar solvents such as water, but generally soluble in nonpolar solvents. In fact, derivatives of benzene are widely used as the solvent for many nonpolar organic compounds. Like other hydrocarbons of comparable molar mass, benzene is a liquid at room temperature. 

Physical Properties. Nitrobenzene is readily soluble in most organic solvents and is completely miscible with diethyl ether and benzene. Nitrobenzene is only slightly soluble in water with a solubiUty of 0.19 parts pet 100 parts of water at 20°C and 0.8 pph at 80°C. Nitrobenzene is a good organic solvent. For example, it is used in Friedel-Crafts reactions because aluminum chloride is soluble in nitrobenzene. The physical properties of nitrobenzene are summarized in Table 1. 

Properties. o-Nitiotoluene [88-72-2] is a clear yeUow liquid. The solid is dimorphous and the melting points of the a- and P-forms ate —9.55 and —3.85 C, respectively. o-Nitrotoluene is infinitely soluble in benzene, diethyl ether, and ethanol. It is soluble in most organic solvents and only slightly soluble in water (0.065 g in 100 g of water at 30°C). The physical properties of o-nitrotoluene are hsted in Table 9. 

Nitrotoluene [99-99-0] crystallizes in colorless rhombic crystals. It is only slightly soluble in water, 0.044 g/100 g of water at 30°C moderately soluble in methanol and ethanol and readily soluble in acetone, diethyl ether, and benzene. The physical properties of -nitrotoluene are Hsted in Table 11. 

Styrene is a colorless Hquid with an aromatic odor. Important physical properties of styrene are shown in Table 1 (1). Styrene is infinitely soluble in acetone, carbon tetrachloride, benzene, ether, / -heptane, and ethanol. Nearly all of the commercial styrene is consumed in polymerization and copolymerization processes. Common methods in plastics technology such as mass, suspension, solution, and emulsion polymerization can be used to manufacture polystyrene and styrene copolymers with different physical characteristics, but processes relating to the first two methods account for most of the styrene polymers currendy (ca 1996) being manufactured (2—8). Polymerization generally takes place by free-radical reactions initiated thermally or catalyticaHy. Polymerization occurs slowly even at ambient temperatures. It can be retarded by inhibitors. 

The physical and thermodynamic properties of benzene are shown in Table 1 (2). Azeotrope data for benzene with selected compounds are shown in Table 2 (3). Benzene forms minimum-boiling azeotropes with many alcohols and hydrocarbons. Benzene also forms ternary azeotropes. 

Physical properties of some commercially available polyamines appear in Table 1. Generally, they are slightly to moderately viscous, water-soluble Hquids with mild to strong ammoniacal odors. Although completely soluble in water initially, hydrates may form with time, particularly with the heavy ethyleneamines (TETA, TEPA, PEHA, and higher polyamines), to the point that gels may form or the total solution may soHdify under ambient conditions. The amines are also completely miscible with alcohols, acetone, benzene, toluene and ethyl ether, but only slightly soluble in heptane. 

In general, pyridazine can be compared with pyridine. It is completely miscible with water and alcohols, as the lone electron pairs on nitrogen atoms are involved in formation of hydrogen bonds with hydroxylic solvents, benzene and ether. Pyridazine is insoluble in ligroin and cyclohexane. The solubility of pyridazine derivatives containing OH, SH and NH2 groups decreases, while alkyl groups increase the solubility. Table 1 lists some physical properties of pyridazine. 

Dispersion of Linear and Nonlinear Optical Properties of Benzene An Ab Initio Time-Dependent Coupled-Perturbed Hartree-Fock Study Shashi P. Kama, Gautam B. Talapatra and Paras N. Prasad Journal of Chemical Physics 95 (1991) 5873-5881... 

Physical properties of alkynes [49, p. 251] are essentially similar to those of alkanes and alkenes. These compounds are weakly polar and are insoluble in water, but they are quite soluble in organic solvents of low polarity (e.g., ether, benzene, CCl ). Chemically, alkynes are more reactive than alkanes but behave like alkenes. The triple bond appears to be less reactive than the double bond in some reagents while more reactive in others. In a chemical reaction, the triple bond is usually broken into a double bond, which may eventually split into single bonds. 

FIGURE 24.2 Physical properties of fuel oxygenates relative to benzene. (Adapted from U.S. EPA, Technologies for Treating MTBE and Other Fuel Oxygenates, EPA 542-R-04-009, United States Environmental Protection Agency, Washington, DC, May 2004.)... 

Suhrmann and co-workers have examined the effects of benzene chemisorption upon a number of physical properties of evaporated metal films... 

Camin, D.L., Forziati, A.F., Rossini, F. (1954) Physical properties of n-hexadecane, n-decylcyclopentane, n-decylcyclohexane, 1-hexadecene and n-decy I benzene. J. Phys. Chem. 58, 440-442. 

Hexaammineplatinum(IV), effective atomic number of noble gas, 7 590t Hexaaquachromium(III) ion, 6 533 Hexaaquamolybdenum(III) ion, 27 26-27 Hexaarylbiimidazolyl (HABI), piezochromic materials, 6 608 Hexabis(benzylthiomethyl)benzene, 24 180 Hexaborane(lO), physical properties of, 4 184t Hexaborane(12), 4 186 Hexabromocyclododecane, 22 467-468 formulations of, 22 460t physical properties of, 4 355t Hexabromocyclohexane, 3 602 Hexachlorobenzene, 3 602 Antoine constants, 6 215t physical and thermodynamic properties, 6 214t... 

The separation of substituted benzene derivatives on a reversed-phase C-18 column has been examined [78]. The correlations between the logarithm of the capacity factor and several descriptors for the molecular size and shape and the physical properties of a solute were determined. The results indicated that hydrophobicity is the dominant factor to control the retention of substituted benzenes. Their retention in reversed-phase HPLC can be predicted with the help of the equations derived by multicombination of the parameters. 

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