Amines using

Strong Base Anion Exchangers. As ia the synthesis of weak base anion exchangers, strong base resias are manufactured from styrenic as well as acryhc copolymers. Those based on copolymers of styrene and divinylben2ene are chloromethylated and then aminated. These reactions are the same as for the styrenic weakbase resias. The esseatial differeace is the amine used for amination. Trimethyl amine [75-50-3] N(CH2)3, and /V, /V- dim ethyl eth a n ol amine [108-01 -0] (CH2)2NCH2CH20H, are most commonly used. Both form quaternary ammonium functional groups similar to (8). 

Health and Safety Factors. Animal-feeding studies of DMPPO itself have shown it to be nontoxic on ingestion. The solvents, catalyst, and monomers that are used to prepare the polymers, however, should be handled with caution. Eor example, for the preparation of DMPPO, the amines used as part of the catalyst are flammable toxic on ingestion, absorption, and inhalation and are also severe skin and respiratory irritants (see Amines). Toluene, a solvent for DMPPO, is not a highly toxic material in inhalation testing the TLV (71) is set at 375 mg/m, and the lowest toxic concentration is reported to be 100—200 ppm (72). Toxicity of 2,6-dimethylphenol is typical of alkylphenols (qv), eg, for mice, the acute dermal toxicity is LD q, 4000 mg/kg, whereas the acute oral toxicity is LD q, 980 mg/kg (73). The Noryl blends of DMPPO and polystyrene have PDA approval for reuse food apphcations. 

Hydrolysis of primary amides cataly2ed by acids or bases is very slow. Even more difficult is the hydrolysis of substituted amides. The dehydration of amides which produces nitriles is of great commercial value (8). Amides can also be reduced to primary and secondary amines using copper chromite catalyst (9) or metallic hydrides (10). The generally unreactive nature of amides makes them attractive for many appHcations where harsh conditions exist, such as high temperature, pressure, and physical shear. 

Schotten-Baumann alkaline conditions from primary and secondary amines using acid chlorides ben2amides from ben2oyl chloride distinguish 1 ° and 2°... 

Alkyl dimethyl and dialkylmethyl tertiary amines are commercially available. These amines are prepared by reductive methylation of primary and secondary amines using formaldehyde and nickel catalysts (1,3,47,48). The asymmetrical tertiary amines are used as reactive intermediates for preparing many commercial products. 

AletalHydrides. Metal hydrides can sometimes be used to prepare amines by reduction of various functional groups, but they are seldom the preferred method. Most metal hydrides do not reduce nitro compounds at all (64), although aUphatic nitro compounds can be reduced to amines with lithium aluminum hydride. When aromatic amines are reduced with this reagent, a2o compounds are produced. Nitriles, on the other hand, can be reduced to amines with lithium aluminum hydride or sodium borohydride under certain conditions. Other functional groups which can be reduced to amines using metal hydrides include amides, oximes, isocyanates, isothiocyanates, and a2ides (64). 

Primary and secondary amines are usually converted to tertiary amines using formaldehyde and hydrogen in the presence of a catalyst (eqs. 5 and 6). This process, known as reductive alkylation (222), is attractive commercially. The desired amines are produced in high yields and without significant by-product formation. Quatemization by reaction of an appropriate alkylating reagent then follows. 

Cationic Starches. The two general categories of commercial cationic starches are tertiary and quaternary aminoalkyl ethers. Tertiary aminoalkyl ethers are prepared by treating an alkaline starch dispersion with a tertiary amine containing a P-halogenated alkyl, 3-chloto-2-hydtoxyptopyl radical, or a 2,3-epoxypropyl group. Under these reaction conditions, starch ethers are formed that contain tertiary amine free bases. Treatment with acid easily produces the cationic form. Amines used in this reaction include 2-dimethylaminoethyl chloride, 2-diethylaminoethyl chloride, and A/-(2,3-epoxypropyl) diethylamine. Commercial preparation of low DS derivatives employ reaction times of 6—12 h at 40—45°C for complete reaction. The final product is filtered, washed, and dried. 

Steam and calcium hydroxide is formed. If the cooling water tends to form acid ia the boiler, either caustic or phosphate may be added to counteract the effect. When the cooling water tends to form base, only phosphate treatment is appropriate. Many dmm boilers that are operated on AVT have provision for phosphate or caustic treatment duriag condenser leaks because the amines used ia AVT have neither significant bufferiag capacity nor precipitate conditioning properties ia the boiler. 

Derivatization of primary and secondary amines using 9-fluorenylmethyl chloroformate to form a nonpolar, uv-absorbing derivative has been reported (90,91). Amphetamine and catecholamine were used as probes to evaluate this procedure. The derivatives were well behaved and allowed separation in a short time. 

Tertiary Amine Catalysts. The Hquid tertiary aHphatic amines used as catalysts in the manufacture of polyurethanes can cause contact dermatitis and severe damage to the eye. Inhalation can produce moderate to severe irritation of the upper respiratory tracts and the lungs. Ventilation, protective clothing, and safety glasses are mandatory when handling these chemicals. 

Aryl isothiocyanates can be prepared by the action of thio-phosgene on the arylamine (this reaction fails with naphthyl compounds), by fission of a 5ym-diaryIthiourea with acidic reagents (this reaction involves the loss of half the amine used), and by the decomposition of an ammonium aryldithiocar-bamate (low yields are reported for naphthyl and other compounds).The procedure described here is that of Baxter, Cymerman-Craig, Moyle, and White. ... 

The most common amine used to cure chlorosulfonated polyethylene is the condensation product between butyraldehyde and aniline. This material is also de-... 

Diisopropanolamine Systems. Diisopropanolamine (DIPA) is a secondary amine used in the Shell ADIP process to sweeten natural gas. DIPA systems are similar to MEA systems but offer the following ad an-tages carbonyl sulfide (COS) can be removed and regenerated easily and the system is generally noncorrosive and requires less heat input. 

The secondary amines used in the preparation of enamines have been primarily simple dialkylamines or cyclic amines of five- or higher-membered rings. Azetidine (4) yields a stable enamine with cyclopentanone (28). No simple enamines formed by condensation of ethylenimine (5) or a substituted ethylenimine with an aldehyde or ketone have been reported. 

Because of self-condensation under the conditions of the alkylation reaction, enamines derived from acetaldehyde or monosubstituted acetaldehydes cannot usually be alkylated 28) except when there is a bulky secondary amine used to produce the enamine 32a). In these cases C alkylation takes place in good yield. 

IPA, NaOH, AC2O, pH 7.8. Phenols are selectively esterified in the presence of other alcohols. These authors also showed that an alcohol could be acetylated in the presence of an amine using AC2O and Amberlyst 15 resin. 

Aminoquinazolines have been the subject of considerable investigation and a large number of derivatives have been prepared as potential antimalarials. The secondary and tertiary amino compounds can be prepared from the corresponding chloroquinazolines and the required primary or secondary amines. The reaction depends on the reactivity of the halogen atom, e.g, the 4-chloro atom reacts more readily than the 2-chloro atom in quinazolines and also on the basic strength of the amine used (see 6a). The reaction is... 

Replacement of the ketone by an amide leads to Increased potency. Hydrolysis of nitrile, 133 (obtained by alkylation of diphenylacetonitrile with the morpholine analog of the chloro-amine used in the original preparation of methadone), affords acid, 134. Conversion to the acid chloride followed by reaction with pyrrolidine affords racemoramide (135) Separation of the (+) isomer by optical resolution gives dextromoramide, an analgesic an order of magnitude more potent than methadone. 

Beside metal salts, a variety of other modifiers, which include amines, chlorobenzene, hydroxides (S2,S2a), and sulfur compounds, have been used. Among amines used are quinoline (SJ0J7,S4), pyridine (29,33,50,60,64), piperidine, aniline, and diethylaniline. The reduction may be quite sensitive to these modifiers for instance, one drop of quinoline was sufficient to cause hydrogenation to come to an abrupt stop after absorption of I mol of hydrogen (2a). 

Problem 24,13 How would you prepare the following amines, using both Hofmann and Curtius rearrangements on a carboxjdic acid derivative ... 

Commercial triethylamine (obtained from Eastman Organic Chemicals), was distilled from phosphorus pentoxide, and the pure amine (b.p. 86-90°) was stored under a nitrogen atmosphere. Since the presence of even a small excess of triethylamine is deleterious in these reactions, the quantities of this amine used should be measured by weight rather than volume. 

Ammonia also may be present as the result of the partial breakdown of amines used for condensate system protection, from hydrazine, or potentially even from nitrate. 

Sometimes the acidity constant (acidity dissociation constant, KJ is employed for the conjugate acid of the amine used. Under these circumstances ... 

Depending on the desired level of humidification and the type of amine used, amine concentrations in air subjected to steam humidification averaged between 0.6 and 8 ppb. 

Hollander, Orin Krager, Richard. Selection Criteria for Amines Used in High-Pressure Boilers. Ultrapure Water, Tall Oaks Publishing, Inc., USA, November 1997. 

Chemists working with azo dyes use a shorthand designation based on the synthesis by azo coupling. It is characterized by an arrow from the amine used for diazotization (the so-called diazo component) to the coupling component, e. g., for 1.8 sulfanilic acid - 2-naphthol. This designation is especially useful for polyazo dyes (see Zollinger, 1991, p. 109). 

Although the oxidation requires 2 mol equiv of oxidant with respect to amine, use of 3 mol equiv of UHP is advised in order to speed up the reaction and to reduce the amount of catalyst required. For example, use of a smaller excess of UHP (2.5 mol equiv) required an increase to 0.7% mol equiv of... 

Scheme 21 Synthesis of isocyanides from amines using PS-reagents...

---