Table of Physical Properties of Common Organic Nitrogen Compounds

Organic nitrogen compounds, including amines, diamines, pyrroles, pyridines, piperidines, and quinolines, are crucial to various chemical and industrial applications. These compounds, distinguished by their nitrogen atoms within diverse structural frameworks, exhibit a range of boiling and melting points influenced by molecular interactions and their structural composition. Alfa Chemistry offers the following tables exploring the physical properties of these compounds, focusing on boiling and melting points, molecular structure, molecular weight, density, and atomic number. This data is critical for applications that require precise control of thermal properties, particularly in areas such as pharmaceuticals, agrochemicals, and polymers.

The boiling point is defined as the temperature at which a liquid turns into a gas, while the melting point is the temperature at which a solid becomes a liquid. These properties are measured under standard atmospheric pressure (1 atm or 760 mm Hg). However, for certain compounds, boiling points under standard pressure are estimated from low-pressure measurements using an enthalpy of vaporization in the range of 54-70 kJ/mol. Notably, this estimation process accounts for an increasing enthalpy with an increase in boiling point, though stability at these estimated temperatures remains uncertain.

Group	IUPAC Name	Common Name	C	H	S	Molweight (g/mol)	Melting Point (℃)	Boiling Point (℃)	Density (@20 ℃ g/ml)
1-Amine	Methylamine	Methanamine	1	5	1	31.06	-93	-6	0.66
1-Amine	Ethylamine	Ethanamine	2	7	1	45.08	-81	17	0.685
1-Amine	Propylamine	1-Propanamine	3	9	1	59.11	-85	47	0.717
1-Amine	Butylamine	1-Butanamine	4	11	1	73.14	-49	77	0.741
1-Amine	Pentylamine	Amylamine	5	13	1	87.16	-51	105	0.754
1-Amine	Hexylamine	1-Hexanamine	6	15	1	101.19	-21	132	0.766
1-Amine	Heptylamine	1-Heptanamine	7	17	1	115.22	-23	153	0.775
1-Amine	Octylamine	1-Octanamine	8	19	1	129.24	0	179	0.783
1-Amine	Nonylamine	1-Nonanamine	9	21	1	143.27	-1	198	0.791
1-Amine	Decylamine	1-Decanamine	10	23	1	157.3	15	217	0.794
1-Amine	Undecylamine	1-Undecanamine	11	25	1	171.32	15	229	0.798
1-Amine	Dodecylamine	1-Dodecanamine	12	27	1	185.35	28	255	0.802
1-Amine	(Tridecyl)amine	1-Tridecanamine	13	29	1	199.38	27	273	0.806
1-Amine	Tetradecylamine	1-Tetradecanamine	14	31	1	213.4	39	289	0.808
1-Amine	Pentadecylamine	Pentadecanamine	15	33	1	227.43	37	312	0.81
1-Amine	Hexadecylamine	1-Hexadecanamine	16	35	1	241.46	46	321	0.813
1-Amine	Octadecylamine	1-Octadecanamine	18	39	1	269.51	53	350	0.862
1-Amine	Icosylamine	1-Eicosanamine	20	43	1	297.56		389
Amine	Dimethylamine	Methyl methylamine	2	7	1	45.08	-92	7	0.654
Amine	Allylamine	2-propen-1-amine	3	7	1	57.09	-88	54	0.758
Amine	Trimethylamine	Dimethyl methylamine	3	9	1	59.11	-117	3	0.631
Amine	2-Propanamine		3	9	1	59.11	-95	32	0.682
Amine	tert-Butylamine	2-Methyl-2-propanamine	4	11	1	73.14	-67	46	0.696
Amine	Diethylamine	Ethyl ethylamine	4	11	1	73.14	-50	56	0.706
Amine	sec-Butylamine	2-Butanamine	4	11	1	73.14	-105	63	0.725
Amine	iso-Butylamine	2-Methyl-1-propanamine	5	12	1	86.16	-85	68	0.73
Amine	Aniline		6	7	1	93.13	-6	184	1.025
Amine	N-allyl-2-propen-1-amine	Diallylamine	6	11	1	97.16		112
Amine	Cyclohexylamine		6	13	1	99.17	-18	134	0.819
Amine	Triethylamine	Diethyl ethylamine	6	15	1	101.19	-115	90	0.727
Amine	o-Toluidine	2-Aminotoluene, 2-Methylaniline	7	9	1	107.15	-28	199	1.01
Amine	p-Toluidine	4-Aminotoluene, 4-Methylaniline	7	9	1	107.15	44	201	0.975
Amine	m-Toluidine	3-Aminotoluene, 3-Methylaniline	7	9	1	107.15	-30	203	1.001
Amine	Allyldimethylamine	N,N-dimethyl-2-propen-1-amine	7	15	1	113.2		62	0.713
Amine	Allyldiethylamine	N,N-diethyl-2-propen-1-amine	7	15	1	113.2		110	0.752
Amine	n-Allylaniline	Allylphenylamine	9	11	1	133.19		219	0.977
Amine	2-Naphthylamine	2-Aminonaphthalene	10	9	1	143.19	112	306	1.063
Amine	4-tert-Pentylaniline		11	17	1	163.26		261
Amine	2-Aminobiphenyl	2-Biphenylylamine, 2-Phenylaniline	12	11	1	169.22	48	299
Amine	Diphenylamine	N-phenyl-aminobenzene	12	11	1	169.22	51	302	1.16
Amine	4-Aminobiphenyl	4-Phenylaniline, Xenylamine	12	11	1	169.22	53	348*
Amine	Alverine	N-ethyl-bis(3-phenylpropyl)-amine	20	27	1	281.44		470*
Pyrrole	Pyrrole	Imidole	4	5	1	67.09	-23	130	0.97
Pyrrole	2,5-Dihydro-1H-pyrrole	Pyrrolines	4	7	1	69.11		90	0.91
Pyrrole	Pyrrolidine	Azacyclopentane, Tetrahydropyrrole	4	9	1	71.12	-58	87	0.859
Pyrrole	1-Ethyl-1H-pyrrole		6	9	1	95.14		130	0.901
Pyrrole	1,2,5-Trimethylpyrrole		7	11	1	109.17		168	0.81
Pyrrole	2,3-Benzopyrrole	1H-Indole	8	7	1	117.15	52	254	1.222
Pyrrole	Indoline	2,3-Dihydroindole, 1-Azaindan	8	9	1	119.16		220	1.065
Pyrrole	Isoindoline		8	9	1	119.16	17	221	1.052
Pyrrole	3-Ethyl-2,4-dimethyl-1H-pyrrole		8	13	1	123.2	0	197	0.913
Pyrrole	1-Phenyl-1H-pyrrole		10	9	1	143.19	61	234
Pyrrole	2-Phenyl-1H-pyrrole		10	9	1	143.19	130	270
Pyrrole	1-phenylpyrrolidine		10	13	1	147.22	11	250*	1.018
Pyridine	Pyridine		5	5	1	79.1	-42	115	0.982
Pyridine	2-Ethylpyridine		7	9	1	107.15	-63	149	0.952
Pyridine	3-Ethylpyridine		7	9	1	107.15	-77	166	0.956
Pyridine	4-Ethylpyridine		7	9	1	107.15	-91	168	0.942
Pyridine	2,3,6-trimethylpyridine	2,3,6-Collidine	8	11	1	121.18		170	0.924
Pyridine	2,4,6-trimethylpyridine	2,4,6-Collidine	8	11	1	121.18	-44	170	0.917
Pyridine	2-(3-pentenyl)pyridine		10	13	1	147.22		216	0.925
Pyridine	2-phenylpyridine		11	9	1	155.2		271	1.085
Pyridine	3-phenylpyridine		11	9	1	155.2		274	1.084
Pyridine	4-phenylpyridine		11	9	1	155.2	70	275
Pyridine	4-(3-cyclohexen-1-y)pyridine		11	13	1	159.23	22	226	1.024
Pyridine	4-Benzylpyridine		12	11	1	169.22		287	1.063
Pyridine	2-(2-Phenylethyl)pyridine		13	13	1	183.25	-2	289	1.039
Pyridine	4-(1-butylpentyl)pyridine		14	23	1	205.34		265	0.89
Piperidine	Piperidine		5	11	1	85.15	-13	106	0.862
Piperidine	4-Phenylpiperidine		11	15	1	161.24	61	257	0.998
Piperidine	1-Phenylpiperidine		11	15	1	161.24	5	260	0.996
Quinoline	Quinoline	1-Azanapthalene	9	7	1	129.16	-15	237	1.096
Quinoline	Isoquinoline		9	7	1	129.16	27	242	1.101
Quinoline	5,6,7,8-tetrahydroisoquinoline		9	11	1	133.19		225*	1.032
Quinoline	1,2,3,4-tetrahydroisoquinoline		9	11	1	133.19	-30	233	1.066
Quinoline	1,2,3,4-tetrahydroquinoline		9	11	1	133.19	10	249	1.063
Quinoline	Perhydroisoquinoline	Decahydroisoquinoline	9	17	1	139.24		212	0.938
Quinoline	Benzo(h)quinoline		13	9	1	179.22	51	341	1.234
Quinoline	Acridine	Dibenzo[b,e]pyridine	13	9	1	179.22	111	347	1.005
Quinoline	Benzo[c]quinoline	Phenanthridine	13	9	1	179.22	107	350
Quinoline	Benzo(f)quinoline		13	9	1	179.22	92	352
Diamine	N-Methylethylenediamine	2-(Methylamino)ethylamine	3	10	2	74.12		115	0.85
Diamine	Ethylenediamine	1,2-Diaminoethane	2	4	2	56.07	9	118	0.902
Diamine	N-Isopropylethylenediamine	2-(Isopropylamino)ethylamine	5	14	2	102.18		136	0.822
Diamine	N,N-Diethylethylenediamine	2-Diethylaminoethylamine	6	16	2	116.2		146	0.83
Diamine	1,5-Diamino-2-methylpentane	2-Methyl-1,5-pentanediamine	6	16	2	116.2		193	0.863
Diamine	1,2-diaminobenzene	o-phenylenediamine	6	8	2	108.14	102	256
Diamine	N-Phenylethylenediamine		8	12	2	136.19		263	1.043
Diamine	1,4-diaminobenzene	p-Phenylenediamine	6	8	2	108.14	140	267
Diamine	N-(Phenylmethyl)-1,2-ethane-diamine		9	14	2	150.22		270*
Diamine	1,3-diaminobenzene	m-phenylenediamine	6	8	2	108.14	65	282
Diamine	1,2-Diphenylhydrazine	Hydrazobenzene	12	12	2	184.24	129		1.156
Diamine	1,1-Diphenylhydrazine		12	12	2	184.24	51	344*	1.188
Diamine	1,1-biphenyl-2,2-diamine		12	12	2	184.24	81	363*	1.309
Diamine	p-Benzidine	1,1-biphenyl-4,4-diamine	12	12	2	184.24	127	401
Diamine	N,N'-Diphenylethylenediamine		14	16	2	212.29	74	404*

* Values estimated for 1 atm from low pressure measurements.

Structure and Intermolecular Interactions

The variations in boiling and melting points among these nitrogen-containing compounds reflect differences in molecular structure and intermolecular forces. For instance, the higher boiling and melting points observed in quinolines compared to amines are attributable to the larger, conjugated ring structure in quinolines, which facilitates stronger π-π interactions and dipole moments. Conversely, with their simple linear or branched structures, primary and secondary amines generally exhibit lower boiling and melting points due to weaker intermolecular hydrogen bonding and van der Waals forces.

The table also illustrates a correlation between molecular weight and boiling point, a trend influenced by the types and arrangements of bonds within these molecules. For instance, ethylenediamine, a diamine, has a higher boiling point than methylamine due to additional hydrogen bonding opportunities provided by the two nitrogen atoms and a more complex molecular structure. The boiling points in this category are particularly relevant for industrial processes, where controlled evaporation rates and temperatures are essential for applications such as solvent recovery, distillation, and formulation development.

Application of Density and Atom Ratios

Density and atomic composition also contribute to the functionality and handling of organic nitrogen compounds. For instance, pyridines and quinolines, with relatively high densities and high carbon-to-nitrogen ratios, are more applicable in organic synthesis for ring-closure reactions, aromatic substitution, and as solvents in reactions requiring stability under various temperature conditions. The higher density of quinoline compared to piperidine underscores its suitability in heavy liquid chromatography and complex chemical synthesis requiring robust, high-density solvents.

In contrast, lighter amines and diamines, due to their lower densities and simpler structures, are more commonly used in pharmaceuticals and agrochemicals, where they serve as precursors for complex compounds. Their relatively low boiling points and densities make them suitable for applications demanding rapid evaporation or diffusion rates, such as in chemical coatings or adhesive formulations.