Benzene melting point

Hydrolysis of the Nitrile.—The nitrile, mixed in a porcelain basin with four times its volume of concentrated hydrochloric acid, is heated on the water bath until an abundant separation of crystals begins to take place on the surface of the liquid. The reaction mixture is then allowed to stand over night in a cool place, and the crystals which have been deposited, after being rubbed with a little water, are separated at the filter pump and washed with water (not too much). A further quantity of the acid is obtained from the filtrate by extraction with ether. The crude mandelic acid is pressed on a porous plate, dried, and purified by crystallisation from benzene. Melting point 118°. Yield about 10-15 g. 

The oximes were prepared by the action of hydroxylamine hydrochloride on the ketones in a slightly alkaline solution and were purified by repeated recrystallization from petrol, ether, ligroin or benzene. Melting points or boiling points of the products were in good agreement with those found in the literature. 

A small test-portion of the crude product is recrystallised from benzene. Melting-point, 8i°. The remainder, without further purification, is worked up into nitrosobenzene. 

Solubility Sparingly soluble in water soluble in ethanol, benzene Melting Point 112-114°C... 

The melting points of a number of sulphonacetamides are —benzene-sulphonic acid, 125° p-toluenesulphonic acid, 137° p-bromobenzene-sulphonic acid, 203° m-nitrobenzenesulphonic acid, 189° p-nitroben-zenesulphonic acid, 192° naphthalene-a-sulphonic acid, 185° and naphthalene-p-sulphonic acid, 146°. 

The high degree of crystallization and the thermal stability of the bond between the benzene ring and sulfur are the two properties responsible for the polymer s high melting point, thermal stability, inherent flame retardance, and good chemical resistance. There are no known solvents of poIy(phenyIene sulfide) that can function below 205°C. 

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. 

The heavy metal salts, ia contrast to the alkah metal salts, have lower melting points and are more soluble ia organic solvents, eg, methylene chloride, chloroform, tetrahydrofiiran, and benzene. They are slightly soluble ia water, alcohol, ahphatic hydrocarbons, and ethyl ether (18). Their thermal decompositions have been extensively studied by dta and tga (thermal gravimetric analysis) methods. They decompose to the metal sulfides and gaseous products, which are primarily carbonyl sulfide and carbon disulfide ia varying ratios. In some cases, the dialkyl xanthate forms. Solvent extraction studies of a large number of elements as their xanthate salts have been reported (19). 

Chlorobenzonitrile [873-32-5] M 137.6, m 45-46°. Crystd to constant melting point from benzene/pet ether (b 40-60°). 

Cyanoacetic acid [372-09-8] M 85.1, m 70.9-71.1°, pK 2.47. Crystd to constant melting point from benzene/acetone (2 3), and dried over silica gel. 

Other purification procedures include the formation of the picrate, prepared in benzene soln and crystd to constant melting point, then decomposed with warm 10% NaOH and extracted into ether the extract was washed with water, and distd under reduced pressure. The oxalate has also been used. The base has been fractionally crystd by partial freezing and also from aq 80% EtOH then from absolute EtOH. It has been distd from zinc dust, under nitrogen. 

Solid sulfonyl cyanides now show a melting point not more than 1-2 below that of recrystallized material. They may be used with t further purification. Analytically pure samples are obtained by r crystallization from dry benzene, diy petroleum ether, or a mixture or the two. 

Since polyethylene is a crystalline hydrocarbon polymer incapable of specific interaction and with a melting point of about 100°C, there are no solvents at room temperature. Low-density polymers will dissolve in benzene at about 60°C but the more crystalline high-density polymers only dissolve at temperatures some 20-30°C higher. Materials of similar solubility parameter and low molecular weight will, however, cause swelling, the more so in low-density polymers Table 10.5). 

At one time the requirement for phenol (melting point 41°C), eould be met by distillation of eoal tar and subsequent treatment of the middle oil with eaustic soda to extraet the phenols. Such tar acid distillation products, sometimes containing up to 20% o-cresol, are still used in resin manufacture but the bulk of phenol available today is obtained synthetically from benzene or other chemicals by such processes as the sulphonation process, the Raschig process and the cumene process. Synthetic phenol is a purer product and thus has the advantage of giving rise to less variability in the condensation reactions. 

A table listing the benzofuroxans Imown to the authors, from the literature or otherwise, with their melting points, appears in Section X, at the end of this chapter. The present section presents a brief summary of the presently available types of substituent groups on the benzene nucleus, and of the reactions they undergo. 

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