Cyclohexylamines, production from aniline

Therefore, CL and die depolymerized product from which CL is regenerated contain various impurities which are present in widely fluctuating amounts depending on the reclamation processes involved. In particular, the presence of cyclohexanone, cyclohexanone oxime, octahydrophenazine, aniline, and other easily oxidized compounds affects die permanganate number. Also volatile substances such as aniline, cyclohexylamine, cyclohexanol, cyclohexanone, nitrocy-clohexanone, and aliphatic amines may also be present in the CL.22... 

The hydrogenation of toluene, aniline, /r-toluidine, and 4-tert-butylaniline was examined over catalyst M1273. The reaction profile for the reactions is shown in Figure 2. From this it can be seen that the order of reactivity is aniline > toluene > /Moluidinc > 4-fer f-butylaniline. The hydrogenation products were methylcyclohexane from toluene, cyclohexylamine from aniline, 4-methyl-cyclohexylamine (4-MCYA) from /Holuidine. and 4-feri-butylcyclohexylamine (4-tBuCYA) from 4-tert-butylaniline. At 50 % conversion the cis trans ratio of 4-MCYA was 2, while tBuCYA it was 1.6. 

In the production of aniline by the hydrogenation of nitrobenzene, the reactor products are separated from unreacted hydrogen in a condenser. The condensate, which is mainly water and aniline, together with a small amount of unreacted nitrobenzene and cyclohexylamine, is fed to a decanter to separate the water and aniline. The separation will not be complete, as aniline is slightly soluble in water, and water in aniline. A typical material balance for the decanter is as follows ... 

The production of aniline is a major international business, carried on in the US, Europe and Asia, mainly for the conversion, by reaction with formaldehyde under acid-catalyzed conditions, into diaminodiphenylmethanes 9a, 9b and 9c, and then into isocyanates, mainly 4,4/-methylenebis(phenylisocyanate) (MDI, also known as 4,4 -methylene-di-paraphenylene isocyanate, 4,4 -diphenylmethane diisocyanate, methylene diphenylene diisocyanate and diisocyanato diphenyl methane) (9d), from which polyurethanes are produced. This accounts for well over 60% of total demand (Figure 1). Aniline is also used in bulk for the production of antioxidants and vulcanization accelerators for rubber. Some 15.5 million lbs. of cyclohexylamine are made each year mainly by catalytic hydrogenation of aniline. Half the demand is for use as a boiler water additive. Other major uses include in the manufacture of herbicides, plasticizers, emulsifying agents, dyes, dry-cleaning soaps, acid gas absorbents and, in Asia, cyclamate sweeteners. Apart from India, the use of aniline for dyestuff manufacture represents about 10% of demand. 

The products are (220), probably formed by the dimerization of (219), and the 2-alkoxy-l,2-thiaphosphole derivatives (218). Analogues of the latter are obtained with p-toluenethiol and dialkylamines. The compound (217 R=Ph) is more reactive than (217 R Me ) and will react with aniline on addition of triethylamine even at room temperature, from which the formation of (221) was observed by spectroscopic characterization. Even more reactive is cyclohexylamine which furnishes an analogue of (221) without addition of strong base. ... 

Spandex stretch fiber, based on polyurethanes, was developed by DuPont and appeared in 1962. From this time, polyurethanes would account for the greater part of demand for anilines. Aniline production alone had more than doubled, to over 100 million lbs. per year, between 1939 and 1957, in part to satisfy demand in products other than dyes. Half the US output was consumed in the production of rubber additives, mainly diphenylamine and cyclohexylamine, the latter used as a chain stopper in manufacture of polyurethanes (also as a boiler water additive and, in the US until banned in 1970, in the manufacture of cyclamate sweeteners). Other polymers, such as epoxy resins, relied on the bulk availability of various aromatic amines (Chapter 14). 

Reduction of anilines to cyclohexylamines over RuOj works successfully on a series of nuclear substituted substrates, at 90-125°C, 8 X 10 kPa, in alcohols or without solvent". Yields of 92% are obtained in the preparation of diamines such as bis(4-aminocyclohexyl) methane, the product being mostly cis,cis and cis,trans isomers . Phenylenediamines are reduced to the 1,3-diamine (91%) or to the 1,4-diamine (88%) over ruthenium-on-alumina in ethanol. The c/j-isomer predominates (70-84%) in a number of solvents and over a range of experimental conditions ". Synthetic advantages can be taken from some side reactions. Hydrogenation of 3,4-diaminobenzoic acid can lead to a mixture of bicyclic lactams that lack an amino substituent . Selective hydrogenation of trisubstituted aniline 9 affords lactame 10, an intermediate in the total synthesis of ibogamine. ... 

The amine aniline is used in the production of dyes with deep shades of color. The common name aniline is derived from the plant in which it was historically obtained. Cyclohexylamine and ethylamine are important in the manufacture of pesticides, plastics, pharmaceuticals, and rubber that is used to make tires. 

In the above study, we have done simulation for production of cyclohexylamine (cyclo-01) in an RCSTR by hydrogenation of aniline. From the results, concluded that mass flow of vapour and liquid flow is 4416.79 kg/h and 96.51kg/h, respectively. The mole fraction of cyclo-01 is about 1.00. Reactor heat duty is -1.9290 (mm KCal/h). The residence time for reaction is 1.24 h. 

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