Nitrobenzenes determination

Solubility of nitrobenzene.—Describe the odor of nitrobenzene. Determine whether nitrobenzene is soluble in alcohol, ether, benzene, dilute hydrochloric acid, and a solution of sodium hydroxide. Mix about 2 cc. of nitrobenzene with 5 cc. of concentrated sulphuric acid and pour the mixture into water. How could you most readily separate into its constituents a mixture of benzene and nitrobenzene ... 

All chemicals were used as described previously [14]. The water content of nitrobenzene determined by Karl-Fischer titration was found to be less than 0.01 % and its conductivity at 298.15 K was 7.98 x 10 S cm . ... 

Table VIII-L-2 gives the upper limit to the rate coefficient of the reaction of O3 with nitrobenzene determined by Atkinson et al. (1987c). The measurement was conducted at ambient temperature and atmospheric pressure by monitoring the decrease of ozone in the presence of known concentrations of nitrobenzene and is the only reported investigation.

Most students will be familiar with simple distillation from their practical inorganic chemistry. Other students should determine the boiling-point of acetone (56°), using a water-bath and water-condenser, or of benzene (81 ), using a sand-bath and water-condenser, and finally of either aniline (184 ) or nitrobenzene (210 ), using for both these liquids a sand-bath and air-condenser. 

Nitrobenzene. Usually rather a troublesome solvent, as it is markedly hygroscopic and the freezing-point of the solvent itself tends to fall steadily moreover it is, like benzene, an associating solvent. For a modification of the above freezing-point apparatus, by which the determination may be made in the absence of water-vapour, the student should consult an advanced textbook of practical physical chemistry. 

Repeat the boiling point determination with the following pure liquids (a) carbon tetrachloride, A.R. (77°) (6) ethylene dibromide (132°) or chlorobenzene (132°) (c) aniline, A.R. (184-6°) and (d) nitrobenzene, A.R. (211°). An air condenser should be used for (c) and (d). Correct the observed boiling points for any appreciable deviation from the normal pressure of 760 mm. Compare the observed boiling points with the values given in parentheses and construct a calibration curve for the thermometer. Compare the latter with the curve obtained from melting point determinations (Section 111,1). 

Determination of boiling points. Distillation method (Fig. II, 12, 1) for carbon tetrachloride (25 nil. distillation flask and small water condenser), and SiwoloboflF s method (Fig. II, 12, 2) for carbon tetrachloride, aniline and nitrobenzene. Calibration curve for thermometer. Determination of b.p. of unknown liquid. 

The object of these studies has been the determination of the degree of association in thiazole and its alkyl derivatives. Various solvents have been used cyclohexane (154), carbon tetrachloride (155, 156), benzene and nitrobenzene (157). 

Studies of the synthesis of quiaolines usiag transition-metal catalysts and nonacidic conditions (55) have determined that mthenium(III) chloride is the most effective of a wide range of catalysts. The reaction between nitrobenzene and 1-propanol or 1-butanol gives 65 and 70% yields of 2-ethyl-3-methylquiQoline [27356-52-1] and 3-ethyl-2-propylquiQoline, respectively. 

Equations 6-94 and 6-97 are first order differential equations, and it is possible to solve for both the eonversion and temperature of hydrogenation of nitrobenzene relative to the reaetor length of 25 em. A eomputer program PLUG61 has been developed employing the Runge-Kutta fourth order method to determine the temperature and eonversion using a eatalyst bed step size of 0.5 em. Table 6-6 shows... 

Thermal decomposition gives olefins, probably by rearrangement of intermediate carbenes. For example, the decomposition of 3,3-penta-methylenediazirine (68) in nitrobenzene above 160°C gives cyclohexene [Eq, (58)]. The yield as determined by bromine titration... 

Aniline usually contains traces of nitrobenzene which can be determined polarographically. 

Finally, determine the polarogram of the aniline solution, and from the wave height deduce the nitrobenzene content of the sample E1/2 ca —0.4 V. 

In the production of TNT from the reaction between toluene and mixed acids (nitric/sulfuric), TeNMe forms in amounts between 0.2—0.4% of the total wt of TNT. This TeNMe has been held responsible for several expins which have occurred in TNT plants, causing fatal injuries to personnel and severe damage to facilities. These expins were attributed to the presence of TeNMe in the acid fume lines and the acid storage tanks. Mixts of TeNMe and readily oxidizable materials are known to form very powerful and sensitive expl mixts. Since TeNMe is also isolated from the nitration of Nitrobenzene (NB), the TeNMe formed in the nitration of toluene may arise from the oxidation of the aromatic ring and/or methyl group. In an effort to gain more informa-. tion on the origin of TeNMe from TNT production, radioactive carbon-14 (14C) was used as a tracer to determine the extent to which each of the carbon atoms in the toluene skeleton of the various nitro-substituted isomers contributes to... 

Hinshelwood et a/.145 measured the rates of sulphonation of a wide range of aromatics by sulphuric acid in nitrobenzene, at temperatures between 5 and 100 °C (Table 32), and in particular the effect of adding up to 0.012 M water was determined. The reaction followed the complex rate law... 

De la Mare and Hilton198 measured the rates at 25 °C of bromination of benzene, benzoic acid, phthalic acid, 2-nitrobenzoic acid, trimethylanilinium perchlorate and nitrobenzene by hypobromous acid with sulphuric or perchloric acids as catalysts, in some cases in aqueous dioxan, in an attempt to discover if Br+ or H2OBr+ was the appropriate brominating species since the logarithm of the rates should then follow the acidity functions H0 or HR (J0) respectively. The results, however, were inconclusive and relative rates of bromination were determined (see Table 53). 

The use of ethylene dichloride as solvent was extended by Brown et al. 11 to the determination of the kinetics of benzoylation of other aromatics, using benzoyl chloride catalysed by aluminium chloride, and the data are included in Table 109 the relative reactivities are thus benzene, 1.0 toluene, 117 o-xylene, 1,393 m-xylene, 3,960 and p-xylene, 243 and these values are closely similar to those obtained with nitrobenzene as solvent. No exact comparison of the coefficients with those of Corriu et al. 16 is possible because of the different temperatures employed, but the rates appear to be comparable for the two sets of data after allowing for reasonable temperature dependencies. 

Brown and McDonald (1966) provided another type of kinetic evidence for these size relationships by determining secondary kinetic isotope effects in reactions of pyridine-4-pyridines with alkyl iodides. For example, the isotopic rate ratio in the reaction between 4-(methyl-d3)-pyridine and methyl iodide at 25-0 C in nitrobenzene solution was determined to be kjyfk = l-OOl, while that in the corresponding reaction with 2,6-(dimethyl-d6)-pyridine was 1-095. (Brown and McDonald (1966) estimate an uncertainty of 1% in the k jk values.) Furthermore, the isotopic rate ratio in the case of the 2-(methyl-d3)-compound increased from 1 030 to 1-073 as the alkyl group in the alkyl iodide was changed from methyl to isopropyl, i.e. the isotope effect increased with increasing steric requirements of the alkyl iodide. 

This approach allowed us also to determine the difference in the surface potentials between mutually saturated water and an organic solvent namely, nitrobenzene, nitroethane and 1,2-dichloroethane, and isobutyl methyl ketone (IBMK). The qualitative data show a very strong influence of the added organic solvent on the surface potential of water, while the presence of water in the nonaqueous phase has practically no... 

GL 18] ]R 1] ]P 19d] Using a high concentration of nitrobenzene, deleterious effects on the catalysts could be determined (1.0 mol 1 60 °C 1 bar 0.5 ml min ) [60, 62]. Both conversion and selectivity were lower compared with processing at 0.04 mol concentration, being 41 and 68%, respectively. The catalyst surface turned dark after prolonged operation and particles settled (8.5 h). As a positive result, the (low) activity remained fairly stable over this period. 

A small quantity of substance is placed on a porcelain plate. Then an hemispheric mass of porcelain is placed on the substance with a weight that can be adjusted and then proceed to a displacement of the porcelain plate. The weight that is necessary to obtain a probability of decomposition of 50% by doing a series of thirty tests is determined m-nitrobenzene gives 0% at 36 kgf (327N). 

---