Physical properties benzene

Nicotinamide is a colorless, crystalline solid. It is very soluble in water (1 g is soluble in 1 mL of water) and in 95% ethanol (1 g is soluble in 1.5 mL of solvent). The compound is soluble in butanol, amyl alcohol, ethylene glycol, acetone, and chloroform, but is only slightly soluble in ether or benzene. Physical properties are Hsted in Table 1. 

Physical Properties. Benzene, C H, toluene, C Hj-CH, and petrol (a mixture of aliphatic hydrocarbons, e.g., pentane, hexane, etc.) are colourless liquids, insoluble in and lighter than water. Benzene and toluene, which have similar odours, are not readily distinguishable chemically, and their physical constants should therefore be carefully noted benzene, m.p. 5 (solidifies when a few ml. in a dry test-tube are chilled in ice-water), b.p. 8i toluene, m.p. —93°, b.p. 110°. Petroleum has a characteristic odour. 

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. 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. 

Riboflavin forms fine yellow to orange-yeUow needles with a bitter taste from 2 N acetic acid, alcohol, water, or pyridine. It melts with decomposition at 278—279°C (darkens at ca 240°C). The solubihty of riboflavin in water is 10—13 mg/100 mL at 25—27.5°C, and in absolute ethanol 4.5 mg/100 mL at 27.5°C it is slightly soluble in amyl alcohol, cyclohexanol, benzyl alcohol, amyl acetate, and phenol, but insoluble in ether, chloroform, acetone, and benzene. It is very soluble in dilute alkah, but these solutions are unstable. Various polymorphic crystalline forms of riboflavin exhibit variations in physical properties. In aqueous nicotinamide solution at pH 5, solubihty increases from 0.1 to 2.5% as the nicotinamide concentration increases from 5 to 50% (9). 

Production of cellulose esters from aromatic acids has not been commercialized because of unfavorable economics. These esters are usually prepared from highly reactive regenerated cellulose, and their physical properties do not differ markedly from cellulose esters prepared from the more readily available aHphatic acids. Benzoate esters have been prepared from regenerated cellulose with benzoyl chloride in pyridine—nitrobenzene (27) or benzene (28). These benzoate esters are soluble in common organic solvents such as acetone or chloroform. Benzoate esters, as well as the nitrochloro-, and methoxy-substituted benzoates, have been prepared from cellulose with the appropriate aromatic acid and chloroacetic anhydride as the impelling agent and magnesium perchlorate as the catalyst (29). 

AHyl chloride is a colorless Hquid with a disagreeable, pungent odor. Although miscible in typical compounds such as alcohol, chloroform, ether, acetone, benzene, carbon tetrachloride, heptane, toluene, and acetone, aHyl chloride is only slightly soluble in water (21—23). Other physical properties are given in Table 1. 

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. 

It is desired to separate a non-volatile material from an equimolal mixture of benzene, toluene, and xylene at 80°C. Vapor pressure data for these compounds are shown in several physical property sources. The following approximate values for the specific heats and latent heats of vaporization may be used ... 

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. 

Although many of the aromatic compounds based on benzene have pleasant odors, they are usually toxic, and some are carcinogenic. Volatile aromatic hydrocarbons are highly flammable and burn with a luminous, sooty flame. The effects of molecular size (in simple arenes as well as in substituted aromatics) and of molecular symmetry (e.g., xylene isomers) are noticeable in physical properties [48, p. 212 49, p. 375 50, p. 41]. Since the hybrid bonds of benzene rings are as stable as the single bonds in alkanes, aromatic compounds can participate in chemical reactions without disrupting the ring structure. 

Isolation of Chromenes. The Skellysolve-F extract of yellow starthistle was partitioned between Skellysolve-F/benzene/methanol/water (1 1 4 1). The lower layer was repeatedly chromatographed on silica-gel (column and preparative TLC) with Skellysolve-F/ether to give pure chromenes identified by comparison of physical properties with those reported (14) and by synthesis. 

Methods utilizing characteristic physical properties have been developed for several chlorinated hydrocarbon insecticides. Daasch (18) has used infrared spectroscopy for the analysis of benzene hexachloride. By this means it is possible to determine the gamma-isomer content, as well as that of the other isomers of technical benzene hexachloride, provided the product is substantially free of the higher chlorinated cyclohexanes. 

Fuel oxygenates generally exhibit the following physical properties relative to benzene ... 

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... 

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