Industrial primary amines

TABLE 1. Examples of environmental, occupational and quality control protocols for industrial primary amines... 

Industrially, polyurethane flexible foam manufacturers combine a version of the carbamate-forming reaction and the amine—isocyanate reaction to provide both density reduction and elastic modulus increases. The overall scheme involves the reaction of one mole of water with one mole of isocyanate to produce a carbamic acid intermediate. The carbamic acid intermediate spontaneously loses carbon dioxide to yield a primary amine which reacts with a second mole of isocyanate to yield a substituted urea. 

Cyclohexylamine is miscible with water, with which it forms an azeotrope (55.8% H2O) at 96.4°C, making it especially suitable for low pressure steam systems in which it acts as a protective film-former in addition to being a neutralizing amine. Nearly two-thirds of 1989 U.S. production of 5000 —6000 t/yr cyclohexylamine serviced this appHcation (69). Carbon dioxide corrosion is inhibited by deposition of nonwettable film on metal (70). In high pressure systems CHA is chemically more stable than morpholine [110-91-8] (71). A primary amine, CHA does not directiy generate nitrosamine upon nitrite exposure as does morpholine. CHA is used for corrosion inhibitor radiator alcohol solutions, also in paper- and metal-coating industries for moisture and oxidation protection. 

There is an industry trend to supply SBR certifiably free of volatile nitrosamines or nitrosatable compounds. This has generally been accomplished by replacing shortstop systems based on carbamates and hydroxyl amines with products that are not based on secondary amines or are secondary amines of high molecular weight, such as dibenzyldithiocarbamate. A more recendy issued patent for ESBR shortstop is based on isopropyUiydroxylamine, a primary amine that does not form nitrosamine (46). 

Alkylamines have a variety of applications in the chemical industry as starting materials for the preparation of insecticides and pharmaceuticals. Labetalol, for instance, a so-called /3-blocker used for the treatment of hi h blood pressure, is prepared by SN2 reaction of an epoxide with a primary amine. The substance marketed for drug use is a mixture of all four possible stereoisomers, but the biological activity derives primarily from the (R,R) isomer. 

The alkyl halide (ethyl bromide in the above equation) can react further with the primary amine produced to give a secondary amine and with that to form a tertiary amine and finally a quaternary ammonium salt. Quaternary ammonium hydroxides are very strong bases like sodium hydroxide. Tetramethylammonium hydroxide is a very important chemical used in the manufacture of semiconductors and other electronic industry products. 

Secondary amines synthesized by catalytic reductive alkylation of primary amines are used in a variety of fine and specialty chemical indnstries. For example, derivatives of cyclohexylamine are used as corrosion inhibitors, N-(l,3-dimethylbntyl)-N -phenyl-p-phenylenediamine (6-PPD) is nsed as an anti-oxidant in rabber indnstiy, several dialkylated diamines are used in the coatings indnstiy, while they are nsed in the pharmacentical industry as pharmacophores (1-7). Harold Greenfield and co-workers have examined the ability of platinum group metals (PGM), base metals, and their snlfides to catalyze rednctive alkylation of primary and secotrdary amines (8-11). They found that different catalysts are optimal for the... 

T. A. Johnson and D. P. Freyberger, Lithium Hydroxide Modified Sponge Catalysts for Control of Primary Amine Selectivity in Nitrile Hydrogenations, Chemical Industries (Dekker), 82 (Catal. Org. React.), 201-227 (2000). 

The improvements made in hydroaminomethylation technology suggest that certain variants of this reaction are sufficiently developed for the potential production of amines. The synthesis of linear tertiary and secondary amines from terminal alkenes shows promise in this regard. Belief s recent contributions towards hydroaminomethylation using ammonia to produce linear primary amines, which are of industrial significance due to their abundance, suggest a bright future for this reaction. Branched selective hydroaminomethylation remains relatively underdeveloped and needs further study. 

Until now, few acyclic N-alkyl imines or the corresponding amines have been found to be of practical industrial importance. Most studies reported herein were carried out with model substrates, especially with the N-benzyl imine of acetophenone 5a and some analogues thereof (Fig. 34.7). One reason for this choice could be the easy preparation of a pure crystalline starting material, and another reason might be that the chiral primary amines can be obtained by hy-drogenolysis of the benzyl group. As can be seen in Table 34.4, there are several catalyst systems with fair to good ee-values and activities. 

The property of being converted by energetic reduction into primary amines belongs to the nitro-compounds both of the aliphatic and of the aromatic series. Six atoms of hydrogen are required for the reduction of each nitro-group. In industry nitrobenzene is reduced, not with expensive tin, but with iron filings or iron powder according to the old method of Bechamp, which is still in use at the present time. The amount of hydrochloric acid indicated by the equation... 

This work describes the application of a previous study which dealt primarily with organic synthesis and physical properties of reaction products of pure fatty acids with BETA. Derivatives to amplify the previous study were prepared from various industrial fatty materials. The reaction product, from 1 mole diethylenetriamine (BETA) with 2 moles fatty acid, was thought to be the primary amine, RC0N(CH2CH2NH2) CH2CH2NHCOR, rather than the secondary amine, as cited in the literature. The amine was readily dehydrated to the imidazoline,... 

Four types of organic amines exist, as shown in Table 4.8 primary amines RNHj, secondary R2NH2, tertiary RsNH, and quaternary R4N (Appendix D). The hydrocarbon chain R is usually of length Cg-Cu, commonly a straight aliphatic chain, but branched chains and aromatic parts also occur. In general the amines extract metal complexes in the order tertiary > secondary > primary. Only long-chain tertiary and—to a smaller extent—quarternary amines are used in industrial extraction, because of their suitable physical properties trioctylam-ine (TOA, 8 carbons per chain) and trilauryl amine (TLA, 12 carbons per chain) are the most frequently used. For simplicity we abbreviate all amines by RN, and their salts by RNH L . 

This process is similar to the formation of an ester by the action of an acid anhydride on an alcohol (described in the earlier section Acid anhydride plus an alcohol ). Half the acid anhydride forms the amide the other half is a leaving group. Ammonia, primary amines, and secondary amines react to produce amides. Figure 12-27 shows the industrial preparation of phenacetin by the reaction of an amine with an acid anhydride. The mechanism for this reaction is similar to the mechanism for the reaction of an acid chloride with an amine (refer to Figure 12-26). 

Oxidation of organonitrogen compounds is an important process from both industrial and synthetic viewpoints . N-oxides are obtained by oxidation of tertiary amines (equation 52), which in some cases may undergo further reactions like Cope elimination and Meisenheimer rearrangement . The oxygenation products of secondary amines are generally hydroxylamines, nitroxides and nitrones (equation 53), while oxidation of primary amines usually afforded oxime, nitro, nitroso derivatives and azo and azoxy compounds through coupling, as shown in Scheme 17. Product composition depends on the oxidant, catalyst and reaction conditions employed. 

Phthalimide. C<,H4 (CO), NH, is an imide of commercial and industrial importance, forming a number of interesting derivatives. With alcoholic potash, phthalimide forms a potassium derivative. C(,H4 (COb -NK. which, when reacted with ethyl iodide (or other alkyl halides), yields eihylphthalimidc. C(,H4 (COi N - C2Hj Ihe latter product, when hydrolyzed wilh an acid or alkali, further yields ethylamine. Such reaction chains are useful in ihe preparation of certain primary amines and their derivatives. 

Using this protocol, primary aliphatic amines, secondary aliphatic amines, and diamines could be converted into the corresponding urea derivatives in moderate yields. Additionally, catalytic efficiency of cations derived from various bases decreases in the order of > diamines > primary amines > secondary amines > aniline, probably being due to the steric effect and basicity. The catalyst could also be recovered after a simple separation procedure, and reused over five times with retention of high activity. This process presented here could show much potential application in industry due to its simplicity and ease of catalyst recycling. 

The use of modified silica in this field was initiated by Leyden and Luttrell.20,21 They used amine-modified silica for the concentration of copper from lake water and high purity industrial water. Both diamine and monoamine modified silicas and their dithiocarbamate derivatives were used. Taylor and Howard22 related the copper capacity of the aminated silicas to the primary amine content. Efficient complexation therefore requires linear rather than bridged chains, with a primary amine ending. 

They are a small class of surfactants with applications in the industrial sector rather than the detergent industry. They are produced using the same equipment as for alcohol ethoxylates but the first step is uncatalysed. Primary amine is dehydrated as normal under vacuum and the reactor nitrogen padded and the required ethylene oxide to produce diethanolamine is added. The addition of the second mole is more rapid than the first but then, even in the presence of excess ethylene oxide, there is little or no ethoxylation of the diethanolamine [32, 33]. This reaction is carried out at about 120°C ... 

In the 1970s and 1980s, a number of amphoteric surfactants were introduced to the market that were based on alkyl polyamines, primary amines upon which is condensed acrylonitrile, then hydrogenated to produce an alkyl propylenediamine and, with additional cycles, alkyl polyamines. These, in turn, are alkylated with sodium chloroacetate to produce alkyl polyamine polycarboxylates. Some of these products find utility in laundry applications, in personal care products and as industrial foamers. 

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