Nitrocompounds, preparation

Phthalocyanine sulfonic acids, which can be used as direct cotton dyes (1), are obtained by heating the metal phthalocyanines in oleum. One to four sulfo groups can be introduced in the 4-position by varying concentration, temperature, and reaction time (103). Sulfonyl chlorides, which are important intermediates, can be prepared from chlorosulfonic acid and phthalocyanines (104). The positions of the sulfonyl chloride groups are the same as those of the sulfonic acids (103). Other derivatives, eg, chlormethylphthalocyanines (105—107), / /f-butyl (108—111), amino (112), ethers (109,110,113—116), thioethers (117,118), carboxyl acids (119—122), esters (123), cyanides (112,124—127), and nitrocompounds (126), can be synthesized. 

Active manganese dioxide was used by Canonica in 19472 for the oxidation of oximes into nitrocompounds before the seminal publication of Ball et al. on the oxidation of vitamin A (76). Canonica prepared active manganese dioxide by reacting MnCb with KMn04. In fact the oxidation power of precipitated manganese dioxide is known since the 1870 s.3... 

One unusual case of anion radical preparation is 4- and 3-nitrocatechol or nitrohy-droquinone. Reduction of these nitrocompounds in aqueous solutions with sodium boro-hydride in air leads to the corresponding anion radicals, which are stable at pH 9-12 despite the presence of water (Grenier et al. 1995). 

The alkylation of ammonia, Gabriel synthesis, reduction of nitriles, reduction of amides, reduction of nitrocompounds, and reductive amination of aldehydes and ketones are methods commonly used for preparing amines. 

Aromatic amines are normally prepared by reduction of the corresponding aromatic nitrocompound. 

Nitration represents a major chemical reaction that plays an essential role in the production of most explosives. A variety of nitrocompounds ranging from C-nitrocompounds such as TNT to N-nitrocompounds such as RDX and HMX to 0-nitrocompounds such as trinitroglycerol are considered among the most energetic compounds. The preparation of these explosives is thus of substantial importance [8]. 

In the laboratory, other metals, like iron, zinc, etc., in connection with an add, are only rarely used in the place of tin or stannous chloride, for the. reduction of nitro-compounds. On the large scale, iron, owing to its cheapness, is used in the preparation of bases like aniline, toluidine, a-naphthyl amine, etc., from the corresponding nitrocompounds. By the use of iron and hydrochloric acid, the reduction should theoretically take place in accordance with the following equation ... 

Besides the reducing agents mentioned, there is still a large number of others which find only an occasional application in reducing nitrocompounds to amines. They will be referred to under the different preparations. 

Aromatic hydroxylamines are generally prepared by chemical reduction or selective hydrogenation of aromatic nitrocompounds by using metal catalysts promoted with dimethylsulfoxide. However, such methods of synthesis are characterized by difficult products purification and low yields /1,2/. The low cost production of arylhydroxylamines can be of great practical interest because these compounds can undergo rearrangement to yield a variety of important chemicals 111. 

Silica gel-supported, cyclized polyacrylonitrile metal complexes as well as PMAA-Pd and PMAA-Pt complexes were prepared by copolymerization of MAA and a mixture of m- and p-DVB in the presence of silica gel [131]. The catalytic activity of the obtained complexes was examined in the reaction of cumene and ethylbenzene hydrogenation [131] and in the hydrogenation of aromatic and aliphatic nitrocompounds, alkenes and aliphatic aldehydes. Based on the decrease in the bond energy of Cu2p3/2 from 935 to 932.4 eV and the increase in the bond energy of Ajs from 399 to 399.6 eV, it was found, by XPS, that Cu is bound to a complex through a nitrogen atom of PAN. 

Methods for Preparing Energetic Nitrocompounds Nitration with Superacid Systems, Nitronium Salts, and Related Complexes George A. Olah... 

Nitrodesilylation with nitronium tetrahuoroborate is also a mild and efficient way to prepare aiiphatic nitrocompounds from readily available alkylsilanes. Olah and Rochin have studied [151] the scope of the reaction, Tetramethylsilane reacts readily with NOJBFJ in sulfolane solution to give nitromethane in 80% yield. 

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