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Diethylamine More Basic Than Triethylamine Reason
The reason why diethylamine is more basic than triethylamine
is that it can release hydroxide ions in water or accept protons in acid-base reactions. Both diethylamine and triethylamine are organic bases, but the basicity of diethylamine is stronger than that of triethylamine. The reasons are as follows.
Effect of Electronic Effect
Alkyl has an electron-giving induction effect. In diethylamine, the nitrogen atom is connected with two ethyl groups. The electron-giving induction effect of ethyl group increases the electron cloud density on the nitrogen atom, and the attraction of nitrogen to protons is enhanced, so the basicity is enhanced. Although triethylamine is connected with three ethyl groups, too many alkyl groups form a steric barrier around the nitrogen atom, which hinders the binding of nitrogen atoms to protons to a certain extent. Although the electron-induced effect of alkyl groups also increases the density of electron clouds on nitrogen, the negative impact of steric barrier cannot be ignored. In contrast, diethylamine has a smaller steric barrier, and nitrogen atoms are more likely to approach protons. Under the combined action of electronic and spatial effects, its ability to accept protons is stronger, and its alkalinity is stronger than that of triethylamine.
Differences in Solvation
In aqueous solutions, ammonium ions formed after protonation of amine compounds can form hydrogen bonds with water molecules, which is the solvation effect. After the protonation of diethylamine, there are more hydrogen atoms around the ammonium ions that can form hydrogen bonds with water molecules, and the solvation effect is stronger, which increases the stability of ammonium ions, thereby promoting the formation of ammonium ions by protons of diethylamine, that is, the alkalinity is enhanced. In contrast, triethylamine, due to the large number of alkyl groups around the nitrogen atom, the steric resistance is large, which hinders the formation of hydrogen bonds between ammonium ions and water molecules, and the solvation effect is weak. The stability of ammonium ions is relatively poor, and the tendency to accept protons is weakened, so its alkalinity is weaker than that of diethylamine.
To sum up, the combined effect of electronic effects and solvation makes the alkalinity of diethylamine stronger than that of triethylamine.
is that it can release hydroxide ions in water or accept protons in acid-base reactions. Both diethylamine and triethylamine are organic bases, but the basicity of diethylamine is stronger than that of triethylamine. The reasons are as follows.
Effect of Electronic Effect
Alkyl has an electron-giving induction effect. In diethylamine, the nitrogen atom is connected with two ethyl groups. The electron-giving induction effect of ethyl group increases the electron cloud density on the nitrogen atom, and the attraction of nitrogen to protons is enhanced, so the basicity is enhanced. Although triethylamine is connected with three ethyl groups, too many alkyl groups form a steric barrier around the nitrogen atom, which hinders the binding of nitrogen atoms to protons to a certain extent. Although the electron-induced effect of alkyl groups also increases the density of electron clouds on nitrogen, the negative impact of steric barrier cannot be ignored. In contrast, diethylamine has a smaller steric barrier, and nitrogen atoms are more likely to approach protons. Under the combined action of electronic and spatial effects, its ability to accept protons is stronger, and its alkalinity is stronger than that of triethylamine.
Differences in Solvation
In aqueous solutions, ammonium ions formed after protonation of amine compounds can form hydrogen bonds with water molecules, which is the solvation effect. After the protonation of diethylamine, there are more hydrogen atoms around the ammonium ions that can form hydrogen bonds with water molecules, and the solvation effect is stronger, which increases the stability of ammonium ions, thereby promoting the formation of ammonium ions by protons of diethylamine, that is, the alkalinity is enhanced. In contrast, triethylamine, due to the large number of alkyl groups around the nitrogen atom, the steric resistance is large, which hinders the formation of hydrogen bonds between ammonium ions and water molecules, and the solvation effect is weak. The stability of ammonium ions is relatively poor, and the tendency to accept protons is weakened, so its alkalinity is weaker than that of diethylamine.
To sum up, the combined effect of electronic effects and solvation makes the alkalinity of diethylamine stronger than that of triethylamine.
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