Amination dyestuff intermediates

Pure samples are best prepd by the methylation of acetanilide or benzanilide to the N-methyl compds followed by acid hyd. It has been prepd commercially by the action of methyl ale on aniline in an autoclave under press and by the action of methyl amine on halobenzenes. For a summary of prepns see Refs 6 9. It may be separated from aniline and dime thy laniline by treatment of the mixt with benzenesulfonyl chloride. Dimethylamline fails to react and is extd out with dil acid. Aniline forms benzenesulfonanilide which is acidic and is removed by washing with dil base, leaving the N-methylbenzenesulfonanilide. Purified N-methylaniline is obtd by acid hyd (Ref 8). N-Methylaniline is used as an additive to raise the octane no of motor fuels (Ref 6), as a dyestuff intermediate (Ref 3), in the prepn of Tetryl (see below), and in the prepn of Methylcentralite (Encycl, Vol 2, C137-R)... 

USE Manuf phenobarbetal, ethyl benzyl maJonate trietliyl-amine, and similar chemicals, plastics, dyestuff intermediates . Solvent for cellulose esters, perfumes. 

World production of hydroquinone is around 25,000 tpa. Hydroquinone is predominantly used in photography as a developer and is employed to produce antioxidants by reaction with amines (see Chapter 6.1.1). It is also a polymerization inhibitor and a dyestuffs intermediate. 

The past experience of the dyestuff industry in its use of dye intermediates such as ( -naphthyl amine and benzidine (4), known human bladder carcinogens (334—343), have led to studies as to whether or not handlers of dyes are exposed to medical ha2ards such as cancer, dermatitis, and other disorders (344-360). 

Herz A process for making o-amino thiophenols by heating the hydrochlorides of aromatic amines with sulfur monochloride at 50 to 75°C. The products are used as intermediates in the manufacture of thio-indigo dyestuffs. Invented by R. Hertz in Germany in 1914. 

The nitration of aromatic hydrocarbons is one of the most widely studied and well-documented reactions in organic chemistry. Aromatic nitro compounds are of huge industrial importance in the synthesis of pharmaceutical drugs, agrochemicals, polymers, solvents and perfumes, and for the synthesis of other industrially important chemicals containing amine and isocyanate functionality. However, early research into aromatic nitration was fuelled exclusively by their use as explosives and intermediates in the synthesis of dyestuffs. The former is the subject of this chapter. 

The catalytic hydrogenation of aromatic nitro compounds is an industrially important process for the preparation of aromatic amines that are used as intermediates for the manufacture of polyurethanes, rubber chemicals, agricultural products, dyestuffs, photographic chemicals, and drugs, as well as various other chemicals. Stratz has com-... 

After diazotisation is completed the liquid is allowed to run into an alkaline solution of the phenol or its sulphonic acid, care being taken that the mixture remains alkaline. After some time the dyestuff is salted out, and is generally filtered through a filter-press. The combination of diazo-compounds with amines is somewhat more complicated. Some of these, for instance metaphenylenediamine, combine with diazo-compounds in neutral aqueous solutions while others, like diphenylamine, are dissolved in alcohol, and a concentrated solution of the diazo-compound gradually added. In the manufacture of amidoazobenzene and all compounds in which an intermediate formation of a diazo-amido-compound takes place, a large excess of the amine has to be employed, to hold the diazoamido-compound formed in solution. 

Use Intermediate in the synthesis of dyestuffs, textile auxiliaries, pharmaceuticals, and corrosion inhibitors curing epoxy, amine, and polyamide resins emulsifier in paints and coatings. 

Nitration is one of the most important reactions in industrial synthetic organic chemistry. Not only do nitration products find wide application as solvents, dyestuffs, pharmaceuticals, and explosives, but they also serve as useful intermediates for the preparation of other compounds, particularly amines which are prepared by the reduction of the corresponding nitro compound. 

This water-white, primary aliphatic amine is available commercially in an anhydrous form. It is soluble In water, methyl and ethyl alcohols, ethyl ether, ethyl acetate, aromatic and aliphatic hydrocarbons, acetone, mineral oil, fixed oils, oleic and stearic acids. It is soluble In hat paraffin and carnouba waxes, which solidify on cooling. It is potentially useful os on intermediate In such manufactured products as dyestuffs, surface-active agents, textile specialties, pharmaceuticals, bactericides, insecticides, and cleaning compounds. It is also used os o dehoiring ogent in the leather industry. 

The practical applicability and accuracy of the PSC method can be demonstrated by the examples of the thermal decomposition of aromatic diazonium salts in sulfuric acid, (important intermediates for the production of dyestuffs). The diazotation of both the amines was carried out by nitrosylsulfuric acid. 

The most important commercial intermediates from aniline are the mixture of 4,4 - and 2,4 -diaminodiphenylmethane, obtained by reaction with formaldehyde, and the higher polyamines as well as 2-mercaptobenzothiazole and cyclohexyl-amine, used as rubber additives. N,N-Dialkylanilines are commonly used for the production of dyestuffs, while phenylhydrazine is used as an intermediate in the manufacture of plant protection agents, pharmaceuticals and dyestuffs. Other important aniline products are sulfanilic acid and acetanilide. 

Amines have a very large number of uses intermediates in the synthesis of polymers, certain insecticides, fungicides, dyestuffs (aniline), and pharmaceuticals. They are used as surfactants, vulcanisation promoters, herbicides, corrosion inhibitors, etc. 

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