Salts, “acid of amines

Interesting data were reported in Reference 98 on the transformation of the sulfuric acid salt of amine under conditions of nitrosation (Scheme 3.37). 

Acid salts of amines (and other basic parents) are indexed at the molecular formulae of the amines. Thus, methanamine hydrochloride appears under CHjN (methanamine) and not under CHgClN. 

The reagent has been used for the cleavage of picric acid salts of amines. The finely divided yellow picrate is shaken with a mixture of ether and a concentrated aqueous solution of ethanolamine, and the ether solution is drawn off and extracted repeatedly with ethanolamine solution until it is no longer colored. Hiinig and Baron studied the velocity of splitting of quaternary ammonium salts on refluxing with ethanolamine. ... 

Amino-alcohols Polyamino-compounds Sulphonic acids Salts of amines or urea Salts of alkali metals Ammonium salts of organic acids... 

COj liberated. All acids esters which hydrolyse easily, e.g., methyl oxalate (p. 357) salts of amines nitrophenols. 

Aromatic amines form addition compounds and complexes with many inorganic substances, such as ziac chloride, copper chloride, uranium tetrachloride, or boron trifluoride. Various metals react with the amino group to form metal anilides and hydrochloric, sulfuric, or phosphoric acid salts of aniline are important intermediates in the dye industry. 

The reaction is of practical importance in the vulcanization of siUcone mbbers (see Rubber compounding). Linear hydroxy-terrninated polydimethyl siloxanes are conveniently cross-linked by reaction with methyldiethoxysilane or triethoxysilane [998-30-1]. Catalysts are amines, carboxyflc acid salts of divalent metals such as Zn, Sn, Pb, Fe, Ba, and Ca, and organotin compounds. Hydroxy-terrninated polysiloxanes react with Si—H-containing polysiloxanes to... 

Hydroxy group containing tertiary amines are also used because they become incorporated into the polymer stmcture, which eliminates odor formation ia the foam (3). Delayed-action or heat-activated catalysts are of particular interest ia molded foam appHcations. These catalysts show low activity at room temperature but become active when the exotherm builds up. In addition to the phenol salt of DBU (4), benzoic acid salts of Dabco are also used (5). 

Most of the inhibitors in use are organic nitrogen compounds and these have been classified by Bregman as (a) aliphatic fatty acid derivatives, b) imidazolines, (c) quaternaries, (d) rosin derivatives (complex amine mixtures based on abietic acid) all of these will tend to have long-chain hydrocarbons, e.g. CigH, as part of the structure, (e) petroleum sulphonic acid salts of long-chain diamines (preferred to the diamines), (/) other salts of diamines and (g) fatty amides of aliphatic diamines. Actual compounds in use in classes (a) to d) include oleic and naphthenic acid salts of n-tallowpropylenediamine diamines RNH(CH2) NH2 in which R is a carbon chain of 8-22 atoms and x = 2-10 and reaction products of diamines with acids from the partial oxidation of liquid hydrocarbons. Attention has also been drawn to polyethoxylated compounds in which the water solubility can be controlled by the amount of ethylene oxide added to the molecule. 

Substances determined amines, amine salts, amino acids, salts of acids... 

In the case of a dibasic acid such as sulfuric acid, the normal as well as the acid salts of the amine are formed as shown by the reactions ... 

Piperidines. Grieco et al. have described a general synthesis of piperidines by reaction of the acid salt of a primary amine with an allylsilane and 2 equiv. of formaldehyde in water. The reaction involves reaction of iminium ion (a), derived from the amine and formaldehyde, with the allylsilane to form a homoallylamine (b), which can form a second iminium ion (c), which cyclizes with capture of water to the piperidine. 

Titration of primary, secondary and tertiary amines, and (/ / ) Titration of halogen acid salts of bases. 

Alkaloids are found mainly in plants, and are nitrogenous bases, typically primary, secondary, or tertiary amines. The basic properties facilitate their isolation and purification. Water-soluble salts are formed in the presence of mineral acids (see Section 4.11.1), and this allows separation of the alkaloids from any other compounds that are neutral or acidic. It is a simple matter to take a plant extract in a water-immiscible organic solvent, and to extract this solution with aqueous acid. Salts of the alkaloids are formed, and, being water soluble, these transfer to the aqueous acid phase. On basifying the acid phase, the alkaloids revert back to an uncharged form, and may be extracted into fresh organic solvent. 

Salts of amines with inorganic or organic acids are named as substituted ammonium salts, except when the nitrogen is part of a ring system. Examples are... 

Kitahara115,116,119,121 arrives at similar conclusions with fatty acid salts of higher aliphatic primary amines in benzene. Large amounts of data on cationic surfactants, particularly, their temperature dependent aggregation were collected by Kertes and coworkers109 n0, 11 141. In a number of cases thermodynamic data were calculated from this temperature dependence119. However, frequently the dependence of the aggregation number on the temperature was not duly considered which makes the derived quantities less useful. 

In this process, the readily soluble co-existing salt is in equilibrium with the target salts, and acts as a buffer to the supersaturation of the opposite enantiomer. Thus, we can carry out the preferential crystallization procedure more easily and effectively. For instance, a-methylbenzylamine cinnamic acid salt can be efficiently resolved by adding hydrochloric acid salt of the racemic amine as a co-existing salt. 

S-Isomer was prepared the next way. To a solution of 160 parts of dibenzoyl d-tartaric acid in 1600 parts of anhydrous ethanol were added for 15 minutes 80 parts of dl-l-(3-trifluoromethylphenyl)-2-ethylaminopropane. After 15 additional minutes, 90.5 parts of crystalline solid were isolated. When this product was recrystallized from 1300 parts of anhydrous ethanol, there was obtained 70 parts of dibenzoyl d-tartarate acid salt of L-l-(3-trifluoromethylphenyl)-2-ethylaminopropane. This salt was treated with 500 parts of 4 N NaOH. The mixture was extracted with 2x200-part portions of diethyl ether and the ether extract was re-extracted with 100 parts of 4 N hydrodiboric acid. After treatment with 120 parts of 4 N NaOH, the free amine amounting to 25 parts distills at 105°-107°C (17.5 mm.). [a]D25 - 9.6° (c=8% in ethanol). 

For the reaction of TDI with a polyether triol, bismuth or lead compounds can also be used. However, tin catalysts are preferred mainly because of their slight odor and the low amounts required to achieve high reaction rates. Carboxylic acid salts of calcium, cobalt, lead, manganese, zinc, and zirconium are employed as cocatalysts with tertiary amines, tin compounds, and tin—amine combinations. Carboxylic acid salts reduce cure time of rigid foam products. Organic mercury compounds are used in cast elastomers and in RIM systems to extend cream time, ie, the time between mixing of all ingredients and the onset of creamy appearance. 

Preparation of Secondary Aliphatic Nitramines. A solution of / ,/ -bis(cyanoethyl)amine (10.0 grams, 0.08 mole) in 60 ml. of methylene chloride was cooled to —30°C., and 5.3 grams (0.04 mole) of nitronium tetrafluoroborate was added over a 10-minute period. The mixture was stirred for 1 hour at 0°C., then 4 hours at room temperature. The hydro-fluoroboric acid salt of / ,/ -bis (cyanoethyl) amine, 8.3 grams, 99% yield,... 

Solutions of dmitramic acid can be used to synthesize dinitramide salts with metal hydroxides, carbonates or oxides, and the salts of amine bases ... 

If present, these modify the functional group(s), e.g., in 3-amino-2-chloro-2-butenoic acid, ethyl ester, hydrochloride. Modifications are used for anhydrides, esters, and salts of acids, oxides, sulfides, and selenides of ring systems containing P and As, hydrazones, and oximes of carbonyl compounds, salts of amines, etc. 

Alkyl Ureas.—By substituting alkyl amines for ammonia in the reaction for the synthesis of urea from carbonyl chloride, or by using alkyl derivatives of ammonium cyanate (cyanic acid salts of alkyl amines), in the Wohler synthesis, alkyl ureas may be obtained. They are of different t es as illustrated by the following formulas showing their relationship to urea. 

Scheme 124 Preparation of methyl methoxy carbamoyl chloride from the sulfuric acid salt of methoxy methyl amine.

Notice the diversity in structure of lhe.se proton dunurs. They include the classical hydrochloric acid (reaction a). Ihc weakly acidic dihydrogen phosphate anion (reaction b). the ammonium cation as is found in ammonium chloride (reaction c), the carboxylic acetic acid (reaction d). Ihc cnolic form of phenobarbital (reaction e), Ihe carboxylic acid moiety of indomelhacin (reaction j), Ihc imidc of saccharin (reaction g). and the prolonaied amine of ephedrine (reaction h). Because all are proton donors, they mu.st be treated as acids when calculating the pH uf a solution or percent ionization of the drug. At the same lime, as nuted below, there are important differences in the pharmaceutical properties of ephedrine hydrochloride (an acid salt of an amine) and lho.se of indomelhacin. phenobarbital. or saccharin. 

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