Aniline consumption

Kinetic curves of phenylglycidyl ether consumption in the reaction with aniline in the presence of dimethylbenzylamine (DMBA) are presented in Fig. 15 a. As can be seen from this figure, addition of DMBA considerably increase the rate of monomer consumption in the initial and especially in the later stages of the reaction. The amount of the monomer consumed during polycondensation and polymerization can be readily determined by a parallel determination of the aniline consumption (Fig. 15 b). 

Note that the reaction rate in the presence of the mixture of amines (Curve 4) considerably exceeds the rate of monomer consumption if the same amines are reacted separately and are involved in polycondensation (Curve 1) and polymerization (Curve 6) therefore, an obvious synergetic effect is operative. Considering the fact that the initial rate of aniline consumption (Fig. 15 b, Curve 4) is practically the... 

Aniline consumption grew at a rate of 5.5 percent per year from 1995 to 2000. It is expected to grow at 3.9 percent per year from 2001 through 2004262. 

The substrate, catalyst and solvent were placed into a glass liner equipped with a magnetic stir bar. The liner was placed in a 250 mL steel autoclave that was then charged at r.t. first with N2, then with H2. The reaction mixture was stirred at r.t. until the hydrogen consumption ceased, after which the H2 was vented, the autoclave flushed with N2 and the reaction mixture filtered off on glass filter. The solution was evaporated and the products crystallized and filtered. The crystalline mixture contained the hydrochloride salt of diamino resorcinol and aniline In order to separate completely diamino resorcinol and aniline, the product mixture has to be recrystallized from hydrochloric acid solution. 

A feasible hydrogenation process was developed for the production of 4,6-diamino resorcinol from 4,6-bisphenylazo resorcinol. In the final process 0.8% catalyst (SQ-6, 10% Pd/C) was nsed in five snbseqnent reactions, this means that the specific catalyst consumption was less than 1 500 with respect to the substrate. The yield of the raw product (diamino resorcinol.2HC1) was quantitative, but its aniline content was 3-6 %, after purification the yield was 74-76%, the purity >99%. Even the color of the product was white. The aniline conld be recycled with more than 80% yield. The key to the improved results is that the hydrogenation was performed in the absence of HCl. After the reaction, the product was treated with HCl under hydrogen, and this procedure improved catalyst life. 

Complete oxidation of organics to COz and water requires the transfer of a large number of electrons (commonly 4e for every C), and hence a very high consumption of energy. The destruction of aniline, for instance, requires 28 electrons per molecule... 

The hydrogenation of nitrobenzene progressed to aniline without any significant by-product formation, only trace amounts of azobenzene were formed (< 1 %) as the reaction went to completion. NMR analysis showed no detectable phenyl hydroxylamine in solution. The hydrogen uptake displayed a smooth curve and the rate of hydrogen consumption coincided with the rate of aniline production. The rate of hydrogenation of nitrobenzene to aniline was 15.5 mmol.mm. g. ... 

In the hydrogenation of azobenzene, the rate of hydrogen consumption followed a smooth curve. The reaction profile showed a direct transformation to aniline with no by-product formation or intermediates detected. The rate of aniline production (8.3 mmol.min. g ) was half the rate of nitrobenzene to aniline. 

Fig. 4. Kinetics of phenylglycidyl ether consumption (1) and relative viscosity changes (2) in the reaction of phenylglycidyl ether (Eo = 4.4 mol 1 1) with aniline (Ao = 4.4 mol l-1) at 363 K 441...

Fig. ISa and b. Kinetic curves of the consumption of phenylglycidyl ether (a) and aniline (b) in the presence of dimethylbenzylamine, mol 1 ...

Using the two most effective modifiers the reaction stops after consumption of the theoretical amount of hydrogen. This is indicated by a sharp decrease of the catalyst potential and no further hydrogen uptake. In the case of the 2-chloro aniline no dehalogenated products are detectable by GLC even after prolonged hydrogenation times. 

Figure 5b depicts a direct solvolysis pathway for water and methanol solvents. Here the BPA can either (i) react by the neat pyrolysis pathway with the consumption of another BPA, to give one mole each of toluene, aniline, and benzalaniline or (ii) proceed through the solvolysis pathway to give oxygenated products and aniline (or N-methylaniline for reaction in methanol). The selectivity to oxygenated products would increase as the solvent loading increases. 

A typical kinetic synergism has been observed for the catalytic effect of iV,iV-dimethyl-4-(2-pyridylazo)aniline (PADA) on the extraction of Ni(pan)2 [72], The extraction rate of Ni(pan)2 into toluene is very slow even under an HSS condition. Whereas, the addition of PADA at the diluted concentration as 10-5M can accelerate the extraction rate about 10 times. The observed extracted species was only Ni(pan)2 and no net consumption of PADA was observed after the extraction, while a significant interfacial adsorption of PADA was observed during the extraction under the HSS condition as shown in Fig. 19. These results were analyzed by the mechanism of the interfacial ligand-substitution reaction ... 

Production and Consumption of Aniline in the World, Xiandai Hyagong, 18 (6), 34-36, June 1998. 

Oxygen reacts very eagerly with radicals but it is not a good inhibitor, mainly because it leads to the production of labile peroxides. In addition, its concentration in the stored monomer is usually low. Antioxidants of the phenol or aniline type are themselves very inefficient inhibitors. However, they significantly reduce the rate of 02 consumption when the latter is present [71]. This probably occurs by way of ROO decomposition to non-radical products so that ROO propagation is prevented [72]. More recently, therefore, the kinetics and mechanism of the inhibition effects of antioxidants (hydroquinone, pyrocatechol derivatives, etc.) in radical polymerizations and copolymerizations have been studied mainly in the presence of oxygen [73, 74],... 

Harris and Buchwald took advantage of the differential reactivity between aryl chlorides and aryl bromides in the Pd-catalyzed C-N bond coupling to design a simple one-pot procedure for the preparation of unsymmetrical tri-arylamines, Eq. (95) [101]. Reaction of the aniline with an aryl bromide and an aryl chloride in the presence of the 6/Pd-catalyst resulted in clean production of the desired triarylamine. After complete consumption of the aryl bromide to furnish the corresponding diarylamine, the aryl chloride then reacted to yield the desired unsymmetrical product. 

It transpired that the toxic oil was rapeseed oil that had been adulterated by the addition of 2 per cent of a chemical called aniline, as required by law in Spain for imported rapeseed oil so that it cannot be used for cooking. This oil had been refined and was sold for human consumption, as had been done before without adverse effects. It would appear that a batch of oil may have been refined differently or somehow became contaminated. The toxic oil was found to come from only one source within a particular refinery. The Spanish government agreed to replace the suspect oil with pure olive oil, after which the number of new cases subsided. Collection of contaminated oils known to be associated with the syndrome for analysis was a difficult task due to the government exchange programme. The results showed that the oil associated with the syndrome had a similar composition to rapeseed oil and contained contaminants as a result of the added aniline and the subsequent refining process. 

It is known that the rapeseed oil had been adulterated with aniline, and that the aniline reacted with fatty acids present in the oil to form anilides. These were detected in the oil collected from victims. A good correlation between the amount of a particular anilide and the occurrence of the syndrome was found, which suggests a relationship between consumption of contaminated oil and the syndrome. However, there were individuals who had apparently consumed the contaminated oil but had not shown symptoms, and vice versa. 

In 1943, Calco produced around 97% of the US consumption of sulfadiazine (79), and was the sole American producer of sulfaguanidine (78), both supplied to the Army and Navy Munitions Board. The armed forces also demanded sulfathiazole (77), which cured several common diseases caused by streptococcus, staphylococcus, pneumonococcus and gonococcus, as well as preventing and curing wounds and burns115. In Britain, ICI stepped up manufacture of aniline and A,A-dimethylaniline for explosives, as well as for antimalarials and other pharmaceutical products116,117. 

While the consumption of aniline and other aryl amines in textile dye manufacture has fallen, certain products, particularly aniline, and heterocyclic aryl amines, notably melamine, are produced on a vast scale for use in the manufacture of rubber products and polymers. The growth in demand, and the move from coal to petrochemical feedstocks, stimulated the development of novel manufacturing technologies, particularly continuous vapor- and liquid-phase processes for aniline. 

Several potential etiologies were investigated, including infectious agents, pet-borne vectors, contaminated food, organophosphate pesticide exposure, and vinyl chloride contamination from food containers, before a link was made between the new disease and the consumption of adulterated cooking oil. Chemical analysis of the case-associated oil identified brassicasterol, a marker for rapeseed oil, trace amounts of aniline, oleyl anilide, and other fatty acid anilides and contaminants (Aldridge, 1992 Posada de la Paz et al., 1996 Ruiz-Mendez et al., 2001). The toxin or toxins appear to be stable in oil, since consumption of toxic oil one year after the main epidemic led to development of the disease. 

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