Diamines aliphatic, basicity

This reaction is simple and qualitative36 37 the diamine can be both an aromatic and an aliphatic diamine. With this method, even star-shaped PAs have been synthesized.37 Solution polymerization from acid chlorides and aliphatic diamines is more difficult due to the strong basicity of the aliphatic amine groups. Acid binders which have been used with aliphatic diamines are the tertiary amines with high kb values these include dimethylbenzylamine and diisopropylethylamine.4 38... 

Acid chlorides are very reactive and at room temperature react readily with amines. Synthesis by interfacial and solution methods is possible. However, care should be taken that the hydrochloric acid produced does not react with unreacted amine groups. With the strong basic aliphatic diamines, the acid binder must preferably be even more basic. The attainable molecular weights are strongly dependent on the concentrations this is particularly the case for easily precipitated terephthalamide polymers. Possible problems with the acid binder can be overcome by starting with silylated diamines.33,34 A typical example for interfacial polymerization of terephthalamides is PA-2,T.66... 

Since the discovery of the exceptional basicity of l,8-bis(dimethylamino)-naphthalene (Alder et al., 1968) and its unusual kinetic behaviour (Hibbert, 1973, 1974, 1975) there has been considerable interest in the acid-base properties of hindered diaminonaphthalenes. 1,8-Bis(dimethylamino)naph-thalene (pK — 12.1 at 25°C and ionic strength 0.1 mol dm-3) (Alder et al., 1968 Hibbert, 1974 Chiang et al., 1980) is more basic than most aliphatic amines and the pAT-values of the partially methylated diamines [52] illustrate the dramatic effect of introducing the fourth methyl group (Alder et al., 1968). Reaction of protonated l,8-bis(dimethylamino)naphthalene with... 

Methylenediamines are readily synthesized from the reaction of secondary amines with formaldehyde. Many aliphatic amines are too basic for direct nitration without a chloride catalyst, and even then, nitrosamine formation can be a problem. Their conversion into intermediate methylenediamines before nitration is therefore a useful route to secondary nitramines. The success of these nitrolysis reactions is attributed to the inherent low basicity of the methylene-diamine nitrogens. 

Nearly all the reported studies have been on chromium(III) complexes (cf. Table XVI). The chromium (III) complexes L4Cr(0H)2CrL44+ with ammonia or aliphatic diamines (en and tn) deprotonate in strongly basic solutions to form blue /i-hydroxo-/i-oxo species, which in some cases have been isolated as stable and crystalline salts, e.g., A,A-... 

The solubility of these dyes is significantly enhanced by introduction of alkenyl [35], hydroxypropyl [36], or polyetheralkyl [37] moieties into the trialkylammonium group. The trialkylammonium group may also be a component of a heterocyclic ring [38], When the trialkylammonium residue contains an alkyl chain of more than 11 carbon atoms, the dyes become soluble in aliphatic and alicyclic hydrocarbons and can be used for the production of printing inks [39], With aromatic diamines as the diazo components, such as 4,4 -diaminodiphenyl sulfone, basic disazo dyes are obtained which are suitable for dyeing acid-modified polyamide materials [40],... 

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. 

A third basic procedure of synthesizing 1,3,2-diazaboracyloalkanes involves the interaction of aliphatic a, co-diamines with boron trihalides in the presence of a tertiary amine as hydrogen halide acceptor as is illustrated by Eq. 5 15>17). 

It was observed that the ethylenediamine derivative (33a) and its metal complexes undergo hydrolysis in strongly acidic dmso-water 80 20 wt/wt media, induced by the highly basic character of the nitrogen atoms of the aliphatic diamine.126,127 However, solutions in neutral or basic conditions were found to be stable. In contrast, (33q) and (33r), derived from o-phenylenediamine and m-phenylenediamine respectively, do not hydrolyze at pH higher than 2.5.123 124 128 The greater difficulty in protonating aromatic diamines compared to aliphatic diamines is believed to be responsible for the stability of these SBs and their complexes in acidic dmso-water solution. 

Surprisingly, by using the reactions via 5 and 6 in Scheme 2, polyamides of high molecular weight are obtained directly from dicarboxylic acids and diamines in N-methylpyrrolidone (NMP) solutions containing pyridine (Table 1)1S. A combination of aromatic diamines with aliphatic dicarboxylic acids gives polymers of higher viscosity than the use of an aliphatic diamine alone. On the other hand, 4,4 -diaminodi-phenylsulfone yields low viscous polymers, probably because of the lower basicity. 

As Table 17 shows, aromatic diamines, from which polymers with good solubility in pyridine are formed, yield higher molecular weight polymers whereas polymers from 4,4 -diaminodiphenylsulfone and p-phenylenediamine are insoluble even in HMPA and display low viscosities in sulfuric acid. On the other hand, aliphatic diamines with high basicity afford polymers of low viscosities in low yields because of the retardation of polycondensation by the formation of pyridine-insoluble and un-reactive ammonium carbamate. The same also applies to the preparation of polythioureas. 

A further variant can be used with strongly basic aliphatic amines and has proved especially valuable for diamines whose hydrochlorides do not react with phosgene first, dry carbon dioxide is led into a solution of the amine in a solvent suitable for the phosgene reaction, this giving a carbamic acid salt ... 

Condensing agents are basic catalysts such as alkali carbonates, hydrogen carbonates, hydroxides, or alkoxides, or primary aliphatic amines or calcium hydroxide zinc chloride may also be used with aromatic aldehydes. Ethylene-diamine was introduced by Lerner972 for use in the synthesis of unsaturated nitriles in the aromatic series and he gave a large number of examples in which yields were around 95%. 

A BMI building block based on 4,4 -bismaleimidodiphenylmethane A basic hot-melt tjrpe, eutectic mixture of BMI based on methyldianiline and aliphatic diamines... 

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