Aniline factor

Compounds. When nitro compounds are reduced by electrochemical methods a number of products are possible depending on such factors as the nature of the electrode, the electrode potential, and the reaction media. For the reduction of nitroben2ene these products include aniline, /)-aminopheno1,j -ch1oroani1ine, phenyUiydroxylamine, a2oxyben2ene, a2oben2ene, and hydra2oben2ene (60). 

This phenomenon is not possible in p-nitrobenzoic acid hence, p-nitrophenol is a stronger acid with respect to p-nitrobenzoic acid than is expected on the basis of a comparison of substituents in which this resonance delocalization is not an important factor. It was, therefore, recommended that Op = 1.27 be used for p-nitro derivatives of phenols and anilines, rather than the Op = 0.78 given in Table 7-10. These enhanced sigma constants, symbolized a, apply primarily to electron-withdrawing groups in reactions aided by low electron density at the reaction site. 

General Conditions for each step and selectivity of m-substituted anilines As previously mentioned, Hauser and Reynolds reported on factors governing the first step of the Conrad-Limpach reaction but they tvere by no means exhaustive. Other than the conditions reported above for the first step, HClAleOH, CHCI3 or CHCI2 (neat or with acid catalyst), PhMe or PhH with removal of water with or without acid catalyst, or EtOH/AcOH/CaS04 were reported to provide the desired enamino-ester from an aryl amine and 3-keto-ester. Hauser and Reynolds also noted that o-nitroaniline and o-nitro-p-methoxyaniline failed to form the desired enamino-ester under conditions which they reported. 

The position of aniline in the above reactivity order deserves special comment. Aniline is less basic than pyridine by a relatively small factor, 0.65 pA units, but is appreciably more polarizable it then seems likely that the inverted order of reactivity is caused by the polarizability term in accordance with Edwards equation. If this is correct, in the reactivity order piperidine > aniline > pyridine, inversion with respect to basicity appears to result from an abnormally high reactivity of aniline rather than from a particularly low reactivity of pyridine. This view differs from that based on relative steric requirements of the reagents, but other factors besides basicity and polarizability may well contribute to the quantitative experimental picture. 

Like aniline point, the K factor differentiates between the highly paraffinic and aromatic stocks. However, within the narrow range (K = 11.5-12.0), the K factor does not correlate between aromatics and naphthenes. Instead, it relates fairly well to the paraffin content (Figure 2-11). The K factor does not provide information as to the ratio of naphthene and paraffin contents. The ratio of naphthenes to paraffins can vary considerably with the same K values (Table 2-8). 

Trend the feedstock properties look for changes in the K factor, 1,050°F+ (565°C+), aniline point, refractive index, and °API gravity. The feed endpoint may have been increased to fill the unit. The conversion penalty may be a small price to pay for the increased capacity, but the penalty can be minimized. Verify that the refinery LP reflects current data on yields and product quality. 

Increase in naphthene, olefin, and aromatic concentration, which is indicated by an increase in the refractive index and decreases in aniline point and K factor... 

Trend the feed API gravity, K factor, and aniline point. Verify any changes in paraffin content of the feed. 

The adsorption pseudo-capacitance, Cg, is dominated by the factor ddjdE and hence a plot of C9 versus E gives direct information about the coverage. Figure 4 shows a Cg-E plot for aniline at mercury in aqueous solu-... 

The prognosis for bioremediation of residues containing polychlorinated anilines and their impurities is rather discouraging. Important factors include (a) limited biodegradability, (b) restricted bioavailability, and (c) the possible formation of oligomeric coupling products. 

Similarly, a catalytic route to indigo was developed by Mitsui Toatsu Chemicals (Inoue et al, 1994) to replace the traditional process, which dates back to the nineteenth century (see earlier), and has a low atom efficiency/high E factor (Fig. 2.15). Indole is prepared by vapour-phase reaction of ethylene glycol with aniline in the presence of a supported silver catalyst. The indole is selectively oxidised to indigo with an alkyl hydroperoxide in the presence of a homogeneous molybdenum catalyst. 

Carcinogenic agents include chemicals in the environment, such as aniline and benzene, which are associated with the development of bladder cancer and leukemia, respectively. Environmental factors, such as excessive sun exposure, also may result in cancer. Viruses, including the human papilloma virus and hepatitis B, maybe associated with the development of cancer. Some of the chemotherapy agents cause secondary cancers after therapy has been completed. Numerous factors may contribute to the development of cancer. 

Dan et al. found that Brij-35 also produces an enhancement of the CL intensity of the reaction of fti.v AL[2-(A, -rnclhyl-2 -pyridiniumyl)ethyl]-AL [(trifluoromethyl)sulfonyl]]oxamide with hydrogen peroxide in the presence of some fluorophors [40], To be precise, the CL intensity increased by a factor of 130 for 8-aniline-1-naphthalenesulfonic acid (ANS) and 5.6 forrhodamine B (RH B), compared to the CL intensity in the absence of surfactant. This leads to an increase of 2-3 orders of magnitude in the linear dynamic ranges and a more precise determination of these analytes. However, improvement of the detection... 

The same authors studied the CL of 4,4,-[oxalylbis(trifluoromethylsulfo-nyl)imino]to[4-methylmorphilinium trifluoromethane sulfonate] (METQ) with hydrogen peroxide and a fluorophor in the presence of a, p, y, and heptakis 2,6-di-O-methyl P-cyclodextrin [66], The fluorophors studied were rhodamine B (RH B), 8-aniline-l-naphthalene sulfonic acid (ANS), potassium 2-p-toluidinylnaph-thalene-6-sulfonate (TNS), and fluorescein. It was found that TNS, ANS, and fluorescein show CL intensity enhancement in all cyclodextrins, while the CL of rhodamine B is enhanced in a- and y-cyclodextrin and reduced in P-cyclodextrin medium. The enhancement factors were found in the range of 1.4 for rhodamine B in a-cyclodextrin and 300 for TNS in heptakis 2,6-di-O-methyl P-cyclodextrin. The authors conclude that this enhancement could be attributed to increases in reaction rate, excitation efficiency, and fluorescence efficiency of the emitting species. Inclusion of a reaction intermediate and fluorophore in the cyclodextrin cavity is proposed as one possible mechanism for the observed enhancement. 

Several studies with rats support the AEGL-3 values. A 10-min exposure to aniline at 15,302 ppm resulted in no toxic effects, and a 4-h exposure at 359 ppm resulted in severe toxic effects but no deaths. Dividing these values by a total uncertainty factor of 100 and scaling across time using C%t=k results in values similar to those derived from the Kim and Carlson (1986) study. Studies with repeated exposures of rats resulted in additional effects on the blood and spleen, but concentrations up to 87 ppm, 6 h/d, 5 d/w for 2 w were not disabling or life-threatening. 

An aniline concentration of 250 ppm, which is projected to result in a methemoglobin level between 70% and 80% after an 8-h exposure was identified as the basis for the AEGL-3. The same uncertainty factors and scaling procedure (the value of k in the formula C1xt=k is 1,200 ppm-min) as used for the AEGL-1 were applied to calculations of the AEGL-3. Calculations are in Appendix B, and values appear in Table 1-10. 

No inhalation slope factor is available for aniline, and the available inhalation studies did not examine the endpoint of carcinogenicity. Based on the chronic oral administration of aniline hydrochloride to CD-F rats (CUT 1982), U.S. EPA in its Integrated Risk Information Systems (IRIS) has estimated an oral slope factor of 5.7x1 OP Vrng/kg/d (U.S. EPA 1994). In that study, spleen tumor incidences in rats administered 0, 200, 600, or 2,000 ppm in the diet were 0/64, 0/90, 1/90, and 31/90, respectively. Aniline also has genotoxic action. 

To convert to a dose or concentration of aniline that would cause an excess cancer risk of 10-4 (a virtually safe dose), the risk is divided by the slope factor dose=risk/slope... 

Data Adequacy The key study was well designed, conducted, and documented. Values were presented graphically. Supporting data were sparse, probably because aniline is not a vapor at room temperature, and poisonings have involved contact with the liquid. Although human data are sparse, it is believed that a total uncertainty factor of 100 is protective of human health. Because aniline is absorbed through the skin, which increases the systemic toxicity, direct skin contact with the liquid would be additive and result in onset of adverse effects at airborne concentrations below the respective AEGL values. Therefore, direct skin contact with the liquid should be avoided. 

The stability of o-sulfonylbenzonitrile oxides and their thiophene analogs probably depends on electronic factors. The same factors do not prevent dimerization, as can be seen from data concerning several differently substituted nitrile oxides of the thiophene series (103). Sterically stabilized 3-thiophenecarbonitrile oxides 18 (R = R1 = R2 = Me R = R2 = Me, R1 = i -Pr), when boiled in benzene or toluene, isomerized to isocyanates (isolated as ureas on reaction with aniline) while nitrile oxides 18 with electron-withdrawing substituents (R1 and/or R2 = SOiMe, Br) dimerized to form furoxans 19. 

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