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Coating with amine compound crosslinking agent
2017-3-31 15:01:58
Coating with amine compound crosslinking agent,Sort is more, amine compounds can produce different under the condition of different alkaline pecking order.
When gas amine compounds of alkaline pecking order
In gaseous state, amine compounds of alkaline strength is mainly affected by electronic effect. Fat because of alkyl amine for electronic effect, make the electron cloud density on the nitrogen atoms increases, namely its ability to accept protons enhancement; For aromatic amine, due to the role of P - F conjugation effect, make the original in the electron cloud density on the aromatic amine nitrogen decreased, namely its ability to accept protons. Therefore, amine compounds, alkaline pecking order for:
> > ammonia fat amine aromatic amine
For in the fatty amine and tertiary amine, usually on the nitrogen atom link alkyl, the more the more alkaline. With methylamine, dimethylamine, trimethylamine, for example, is as follows:
(CH3) 3 n > (CH3) 2 nh > CH3NH2 > NH3
To replace the aromatic amine alkali strength depends on the nature of the substituent on the benzene ring, if the base is for the electronic base, aromatic amine alkali enhancement: if is electron-withdrawing substituents, weakened the alkaline. Such as:
NH2 > NH2 > NO2
Amine compounds in aqueous alkaline pecking order
Amine compounds in aqueous solution, in addition to the electronic effect factors which influence the intensity of alkaline, and solvation effect and space effect. Therefore, we are talking about amine compounds in aqueous alkaline strength, must balance these three factors, only in this way can a more comprehensive, more accurate judgment its alkaline pecking order.
Aliphatic amine alkali pecking order in aqueous solution
Aliphatic amine is not the size of the Kb values with a linear relationship with the number of methyl (ethyl). Three methyl trimethylamine, according to the electron theory, the electron density on the nitrogen atom should be the biggest, in methylamine, dimethylamine and trimethylamine in these three should have the strongest alkaline, it is not the case, this is because in addition to the electronic effect, there is space effect and solvation effects in aqueous solution, these two aspects is also directly affect the amine alkali strength.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Uses:
The product is identical to Ethancure 100 and Lonza DETDA 80, DETDA is very effective polyurethane elastomer chain extender; also be used as polyurethane and epoxy resin curing agent, epoxy resin of an antioxidant, industrial oils and lubricants . In addition, also as intermediates in organic synthesis.Especially for the RIM (reaction injection molding), is important in the field of spray polyurea chain extender species. Also can be used for casting polyurethane elastomer (CPU) and a curing agent, epoxy curing agent, epoxy resin of antioxidants, lubricants and industrial oils other antioxidants.
Amine formed by ammonium cations can be stable in aqueous solution by solvent into water used, tertiary amine hydrogen nitrogen atoms have no, so its ammonium cations with water to form hydrogen bond of solvation effect is much weaker than primary and secondary amines, at the same time, the space block is bigger also, so the tendency of the protonation bieber, secondary amine, these two aspects of adverse factors and three for electron induced effect of alkyl this advantageous factors of phase equilibrium result, dimethylamine alkaline the weakest, but still better than ammonia. Therefore, methylamine, dimethylamine and trimethylamine in aqueous alkaline pecking order for:
(CH3) 2 nh > CH3NH2 > (CH3) 3 n > NH3
Formation of ammonium is above the capability: the solvation effect of alkyl number increases, the ammonium cations and solvent molecules form hydrogen bonding opportunities to reduce, the degree of solvation is reduced, the ammonium cations was less stable, its basic also weakened.
"Accordingly, amine alkali is electronic effect and solvation effects such as the result of comprehensive factors.
Aromatic amine alkali strength in aqueous solution
On the one hand, because of the existence of P - F conjugation effect of aromatic amine alkali decreases, and with the P - F the stronger the conjugative effect, aromatic amine alkali weaker. Space effect and solvent effect, on the other hand, has had an impact on their basic, the bigger the space block, the formation of ammonium cation stability is poorer, solvation effect is weaker at the same time, it is weakly alkaline.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Diethyl toluene diamine(DETDA) http://www.yaruichem.com
When gas amine compounds of alkaline pecking order
In gaseous state, amine compounds of alkaline strength is mainly affected by electronic effect. Fat because of alkyl amine for electronic effect, make the electron cloud density on the nitrogen atoms increases, namely its ability to accept protons enhancement; For aromatic amine, due to the role of P - F conjugation effect, make the original in the electron cloud density on the aromatic amine nitrogen decreased, namely its ability to accept protons. Therefore, amine compounds, alkaline pecking order for:
> > ammonia fat amine aromatic amine
For in the fatty amine and tertiary amine, usually on the nitrogen atom link alkyl, the more the more alkaline. With methylamine, dimethylamine, trimethylamine, for example, is as follows:
(CH3) 3 n > (CH3) 2 nh > CH3NH2 > NH3
To replace the aromatic amine alkali strength depends on the nature of the substituent on the benzene ring, if the base is for the electronic base, aromatic amine alkali enhancement: if is electron-withdrawing substituents, weakened the alkaline. Such as:
NH2 > NH2 > NO2
Amine compounds in aqueous alkaline pecking order
Amine compounds in aqueous solution, in addition to the electronic effect factors which influence the intensity of alkaline, and solvation effect and space effect. Therefore, we are talking about amine compounds in aqueous alkaline strength, must balance these three factors, only in this way can a more comprehensive, more accurate judgment its alkaline pecking order.
Aliphatic amine alkali pecking order in aqueous solution
Aliphatic amine is not the size of the Kb values with a linear relationship with the number of methyl (ethyl). Three methyl trimethylamine, according to the electron theory, the electron density on the nitrogen atom should be the biggest, in methylamine, dimethylamine and trimethylamine in these three should have the strongest alkaline, it is not the case, this is because in addition to the electronic effect, there is space effect and solvation effects in aqueous solution, these two aspects is also directly affect the amine alkali strength.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Uses:
The product is identical to Ethancure 100 and Lonza DETDA 80, DETDA is very effective polyurethane elastomer chain extender; also be used as polyurethane and epoxy resin curing agent, epoxy resin of an antioxidant, industrial oils and lubricants . In addition, also as intermediates in organic synthesis.Especially for the RIM (reaction injection molding), is important in the field of spray polyurea chain extender species. Also can be used for casting polyurethane elastomer (CPU) and a curing agent, epoxy curing agent, epoxy resin of antioxidants, lubricants and industrial oils other antioxidants.
Amine formed by ammonium cations can be stable in aqueous solution by solvent into water used, tertiary amine hydrogen nitrogen atoms have no, so its ammonium cations with water to form hydrogen bond of solvation effect is much weaker than primary and secondary amines, at the same time, the space block is bigger also, so the tendency of the protonation bieber, secondary amine, these two aspects of adverse factors and three for electron induced effect of alkyl this advantageous factors of phase equilibrium result, dimethylamine alkaline the weakest, but still better than ammonia. Therefore, methylamine, dimethylamine and trimethylamine in aqueous alkaline pecking order for:
(CH3) 2 nh > CH3NH2 > (CH3) 3 n > NH3
Formation of ammonium is above the capability: the solvation effect of alkyl number increases, the ammonium cations and solvent molecules form hydrogen bonding opportunities to reduce, the degree of solvation is reduced, the ammonium cations was less stable, its basic also weakened.
"Accordingly, amine alkali is electronic effect and solvation effects such as the result of comprehensive factors.
Aromatic amine alkali strength in aqueous solution
On the one hand, because of the existence of P - F conjugation effect of aromatic amine alkali decreases, and with the P - F the stronger the conjugative effect, aromatic amine alkali weaker. Space effect and solvent effect, on the other hand, has had an impact on their basic, the bigger the space block, the formation of ammonium cation stability is poorer, solvation effect is weaker at the same time, it is weakly alkaline.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Diethyl toluene diamine(DETDA) http://www.yaruichem.com
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