Nickel catalyst 4-Nitroaniline

The traditional treatment of nitrobenzene (1) with iron and acid, called Bechamp reduction, was employed almost exclusively in the production of aniline (2) and many aromatic amines until the 1960s1,2 (Scheme 1). The reduction is straightforward, and can also be achieved by catalytic hydrogenation, sodium sulfide reduction and zinc reduction with caustic soda. Nitrotoluenes and nitroxylenes are hydrogenated under pressure over a nickel catalyst supported on kieselguhr. The sulfide reduction is useful in selective reduction, such as of m-dinitrobenzene to m-nitroaniline. 

Nickel Catalyst, dry Nickel Cyanide Nickel Nitrate Nickel Nitrite Nicotine Nicotine Compound, liquid, n.o.s. 2881 1653 2725 2726 1654 3144 1655 37 53 35 35 55 55 Nitriles, toxic, n.o.s. (solid) Nitrites, inorganic, aqueous solutions, n.o.s. Nitrites, inorganic, n.o.s. Nitroanilines Nitroanisole 3276 3219 2627 1661 2730 55 35 35 55 55... 

Palladium containing alumina supported catalysts were designed for hydrodechlorination of chlorobenezne and for conversion of 4-chloro-2-nitroaniline, in which both hydrodechlorination and reduction steps are involved. Best results were obtained on catalysts containing palladium in ionic form. For reductive amination of acetone a skeletal nickel catalyst and its tin modified version was designed. On these catalysts the ratio of primary to secondary amines could be controlled and the fonuation of isopropyl alcohol was strongly suppressed. 

Porphyrins are often employed in sensors on account of their ability to act as cation hosts and, with a suitable metal ion coordinated, as redox catalysts. Electropolymerised poly(metalloporphyrin)s have been used as potentiometric anion-selective electrodes [131] and as amperometric electrocatalytic sensors for many species including phenols [132], nitrous oxide [133] and oxygen [134]. Panasyuk et al. [135] have electropolymerised [nickel-(protoporphyrin IX)dimethylester] (Fig. 18.10) on glassy carbon in the presence of nitrobenzene in an attempt to prepare a nitrobenzene-selective amperometric sensor. Following extraction of the nitrobenzene the electrode was exposed to different species and cyclic voltammetric measurements made. A response was observed at the reduction potential of nitrobenzene (the polyporphyrin film acts only to accumulate the analyte and not in a catalytic fashion). Selectivity for nitrobenzene compared with w-nitroaniline and o-nitroto-luene was enhanced compared with an untreated electrode, while a glassy carbon-... 

Of the derivatives of p-phenylenediamine, the most effective are the N, N -di-alkyl derivatives, in which the alltyl possesses a branched hydrocarbon chain on the carbon closest to the nitrogen atom [235]. They are usually produced by reductive allq lation of p-nitroaniline, p-phenyl-enediamine, p-nitrodiphenylamine, p-nitrosodiphenylamine, or p-amino-diphenylamine with aldehydes and ketones [236-252] with hydrogen at a temperature of 100-250°C and a pressure from 5 to 200 atm in the presence of catalysts. Copper-chromium catalysts (mixtures of oxides of the metals chromium, copper, barium, etc.) [241, 242, 245-247, 249, 250], iodine in the presence of HCl, HBr, or HI [253, 254], Pt/C [245, 252], and Raney nickel [244] are most often used as the catalysts. 

We have utilized this reaction path with some modifications (scheme 3). The diketene addition to 4-chloro-2-nitroaniline occurred spontaneously at room temperature with traces of 4-dimethylaminopyridine. Cyclisation and reduction were then completed in a one-pot procedure in a mixture of isopropanol and water. This allow the use of only 2.2 equivalents of sodium hydroxide instead of 5 to 6 in water and to control the temperature of the cyclisation at "65 C. Various catalysts, particularly Raney nickel or palladium on charcoal (8) were known to be efficient for the hydrogenation of the N-oxide. Eventual overreduction to the 3,4-dihydro-2(lH)-quinoxalinone could be smoothly compensated by reoxidising with hydrogen peroxide or air (9). 

Neopentyl glycol, polyesters use, 494 Nickel, MA bisadduct, 212 Nickel carbonyl, MA complex, 212 Nickel chloride, MA distillation additive, 22 Nickel oxide, oxidation catalyst, 31, 36 Nicotinic acid, use in polyesters, 490 Nitrile imines, dimethyl fumarate adduct, 225 Nitrile oxides, MA adducts, 225 Nitriles, Michael addition to maleates, 64 Nitrile sulfides MA adducts, 225 maleimide adducts, 227 p-Nitroaniline, permaleic acid oxidation, 77 Nitrobenzene, 180 ene reaction solvent, 166 Friedel-Crafts acylation solvent, 93, 97 2-Nitrofuran, 127... 

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