Amination reactions alkylamines

Method 7. Alkyl haHde amination reaction of ammonia or alkylamine with an alkyl haHde. 

Alkylamines, such as butylamines, can be obtained by direct catalytic amination if the amination reaction is carried out in the presence of a fairly large excess of hydrogen. With specific nickel-, copper-, and cobalt-based catalysts which promote hydrogenation and dehydrogenation reactions, yields and conversions per pass of better than 95 per cent are obtained. See Sec. V for more detailed information on this procedure. 

In some amination reactions the starting aromatic substrate itself can act as an acceptor of the hydride ion. For example, l//-thioxanthene-l,4,9-trione reacts with alkylamines in CH2CI2 (toluene or DMSO) to give the corresponding 2-amino compound in addition to l,4-dihydroxy-9//-thioxanthen-9-one (Scheme 18) [70]. 

Benzoxazoles (5-H, 5-Me, 5-Cl, 5-i-Bu, 6-Me, 6-NO2) and naphtho[2,l-d] oxazole were aminated with alkylamines in acetonitrile in the presence of catalytic amounts of tetrabutylammonium iodide, aqueous solution of H2O2 or f-BuOOH and acetic acid (Scheme 44) [100, 101], The reaction occurs quite well even with aqueous ammonia, although the catalyst quantity must be increased from 5 to... 

Arylamines are prepared by nitration of an aromatic ring followed by reduction. Alkylamines are prepared by Sn2 reaction of ammonia or an amine with an alkyl halide as well as by a number of reductive methods, including LiAlH4 reduction of amides and nitriles. Also important is the reductive amination reaction in which an aldehyde or ketone is treated with an amine in the presence of a reducing agent. 

A method that achieves the same end result as that desired by alkylation of ammonia but which avoids the formation of secondary and tertiary amines as byproducts is the Gabriel synthesis Alkyl halides are converted to primary alkylamines without contam mation by secondary or tertiary amines The key reagent is the potassium salt of phthal imide prepared by the reaction... 

Lower aHphatic amines can be prepared by a variety of methods, using many different types of raw materials. By far the largest commercial appHcations involve the reaction of alcohol with ammonia to form the corresponding amines. Other methods are employed depending on the particular amine desired, raw material availabiHty, plant economics, and the abiHty to seU co-products. The foUowing manufacturing methods are used commercially to produce the lower aLkylamines. Table 5 gives plant and capacity information for these methods. 

To manufacture the lower aLkylamines by Method 1, ammonia and alcohol are passed continuously over a fixed bed containing the catalyst in a gas—soHd heterogeneous reaction. The ammonia to alcohol mole ratio varies from 2 1 to 6 1 depending on the amine desired as shown in Figure 1. Operating conditions are maintained in the range from 300—500°C and 790—3550 kPa (100—500 psig) at a gas hourly space velocity between 500—1500 vol/vol per hour. Yields are typically in excess of 90%. 

Olefin Amination (Method 6). The most recent technology for the production of lower alkylamines is olefin amination (14). This is 2eohte-cataly2ed reaction of ammonia with an olefin, eg, isobutylene, and is practiced in a packed-bed reactor system in the vapor phase. 

Amination. Amyl alcohols can react with ammonia or alkylamines to form primary, secondary, or tertiary-substituted amines. Eor example, 3-methyl-butylamine [107-85-7] is produced by reductive ammonolysis of 3-methyl-1-butanol over a Ni catalyst at 150°C (59). Some diisoamyl- and triisoamyl amines are also formed in this reaction. Good selectivities (88%) of neopentyl amine [5813-64-9] are similarly produced by reductive ammonolysis of neopentyl alcohol (60). 

Various sources of fluoride ion have been investigated, of which highly nucleophilic tetraalkylammonium fluorides ate the most effective Thuf, fluoro alkyl halides and N (fluoroalkyl)amines are efficiently synthesized by treatment of the corresponding trifluoromethanesulfonic esters with tetrabutylammonium fluoride trihydrate in aprotic solvents [5fl] (equation 34) The displacement reactions proceed quantitatively at room temperature within seconds, but tail with hydrogen fluoride-pyridine and give reasonable yields only with hydrogen fluo ride-alkylamine reagents... 

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