Cyclohexane (data page)

This page provides supplementary chemical data on cyclohexane.

Material Safety Data Sheet

The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source and follow its directions.

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Structure and properties

Structure and properties
Index of refraction, nD	1.4262 at 20 °C
Abbe number	?
Dielectric constant, εr	2.023 ε0 at 20 °C
Bond strength	?
Bond length[1]	230 pm H–C
Bond angle	109.5° H–C–H 109.5 °C–C–C 109.5° H–C–C
Magnetic susceptibility	?
Surface tension	27 dyn/cm    at 10 °C 25.3 dyn/cm at 20 °C 15.7 dyn/cm at 80 °C
Viscosity[2]	1.03 mPa·s at 17 °C 0.93 mPa·s at 22 °C 0.86 mPa·s at 27 °C 0.75 mPa·s at 35 °C

Thermodynamic properties

Phase behavior
Triple point	279.48 K (6.33 °C), 5.388 kPa[3]
Critical point	554 K (281 °C), 4070 kPa
Std enthalpy change of fusion, ΔfusHo	2.68 kJ/mol crystal I → liquid
Std entropy change of fusion, ΔfusSo	9.57 J/(mol·K) crystal I → liquid
Std enthalpy change of vaporization, ΔvapHo	32 kJ/mol
Std entropy change of vaporization, ΔvapSo	111.80 J/(mol·K)
Solid properties
Std enthalpy change of formation, ΔfHosolid	? kJ/mol
Standard molar entropy, Sosolid	? J/(mol K)
Heat capacity, cp	? J/(mol K)
Enthalpy of transition, ΔtrsHo	6.7 kJ/mol at –87.0 °C crystal II → crystal I
Entropy of transition, ΔtrsSo	36 J/(mol·K) at –87.0 °C crystal II → crystal I
Liquid properties
Std enthalpy change of formation, ΔfHoliquid	–156.4 kJ/mol
Standard molar entropy, Soliquid	204 J/(mol K)
Enthalpy of combustion, ΔcHo	–3919.6 kJ/mol
Heat capacity, cp	156 J/(mol K) or 1.85 J/(g K)
Gas properties
Std enthalpy change of formation, ΔfHogas	–123.1 kJ/mol
Standard molar entropy, Sogas	298.19 J/(mol K)
Heat capacity, cp	105.3 J/(mol K)
van der Waals' constants[4]	a = 2311 L2 kPa/mol2 b = 0.1424 liter per mole

Vapor pressure of liquid

P in mm Hg		1	10	40	100	400	760	1520	3800	7600	15200	30400	45600
T in °C		–45.3(s)	–15.9(s)	6.7	25.5	60.8	80.7	106.0	146.4	184.0	228.4	—	—

Table data obtained from CRC Handbook of Chemistry and Physics 44th ed. The "(s)" annotation indicates equilibrium temperature of vapor over solid. Otherwise value is equilibrium temperature of vapor over liquid.

log₁₀ of Cyclohexane vapor pressure. Uses formula: ${\displaystyle \scriptstyle \log _{e}P_{mmHg}=}$${\displaystyle \scriptstyle \log _{e}({\frac {760}{101.325}})-9.200978\log _{e}(T+273.15)-{\frac {6354.898}{T+273.15}}+75.65058+7.374814\times 10^{-06}(T+273.15)^{2}}$ obtained from CHERIC^[5]

Distillation data

Vapor-liquid Equilibrium for Cyclohexane/Benzene[6] P = 760 mm Hg
BP Temp. °C	% by mole benzene
	liquid	vapor
79.5	10.1	13.1
78.9	17.1	21.1
78.4	25.6	29.3
77.8	34.3	37.6
77.5	42.8	44.5
77.4	52.5	52.9
77.4	57.1	56.4
77.6	66.5	64.5
77.9	75.9	72.8
78.2	81.0	77.7
78.6	86.3	83.4
79.3	94.5	92.6

Vapor-liquid Equilibrium for Cyclohexane/n-Hexane[6] P = 101.0 kPa
BP Temp. °C	% by mole n-hexane
	liquid	vapor
80.60	0.00	0.00
78.87	7.9	12.12
78.15	12.50	18.30
77.36	18.06	25.19
76.85	21.65	29.30
76.29	25.92	34.13
75.85	29.39	37.92
75.29	33.52	42.38
75.29	37.86	46.93
74.23	41.63	50.71
73.58	46.72	55.63
73.11	50.66	59.21
72.26	59.26	67.28
71.11	69.43	76.07
70.45	76.18	81.40
69.05	90.70	93.13
68.64	100.00	100.00

Vapor-liquid Equilibrium for Cyclohexane/Acetic acid[6] P = 101.325 kPa
BP Temp. °C	% by mole acetic acid
	liquid	vapor
79.60	2.75	6.31
79.32	5.20	9.85
78.84	101.2	15.01
78.53	14.06	18.04
78.50	21.39	21.98
78.81	35.30	26.20
79.13	49.30	29.00
79.33	56.10	30.00
81.44	74.60	33.50
81.66	75.80	34.20
85.18	86.70	40.00
90.52	92.50	49.20
91.90	93.20	51.70
95.52	94.57	57.82
98.94	95.96	63.33
105.75	97.84	75.69
113.16	99.33	90.67

Vapor-liquid Equilibrium for Cyclohexane/Ethanol[6] P = 760 mm Hg
BP Temp. °C	% by mole ethanol
	liquid	vapor
73.99	2.0	17.5
69.08	3.0	30.2
66.94	6.5	35.8
66.08	8.1	36.3
66.37	8.6	36.5
65.59	12.5	38.8
65.23	15.1	39.6
65.12	20.6	40.8
64.93	25.8	41.5
64.87	28.3	41.8
64.84	31.5	42.6
64.78	36.6	43.0
64.77	40.3	43.1
64.77	43.1	43.1
64.78	44.4	43.8
64.81	50.0	44.3
64.88	55.7	45.5
65.01	61.3	46.0
64.99	62.1	45.8
65.25	67.8	47.5
65.56	73.8	50.5
66.03	76.3	49.6
65.93	77.6	51.5
66.40	78.1	49.8
66.90	80.9	54.5
67.26	83.3	57.8
67.98	85.3	59.5
68.86	88.1	62.3
69.44	89.8	65.3
70.11	90.9	67.8
71.42	92.9	72.5
72.48	95.1	77.8

Vapor-liquid Equilibrium for Cyclohexane/Isopropanol[6] P = 760 mm Hg
BP Temp. °C	% by mole cyclohexane
	liquid	vapor
78.71	2.7	11.2
76.91	7.0	21.8
74.96	11.6	28.3
74.80	12.0	27.6
72.28	19.1	37.1
70.19	30.6	48.9
69.35	47.3	55.5
69.20	51.6	57.0
69.14	51.6	57.2
69.11	51.8	56.8
68.80	52.8	58.3
69.01	53.8	58.2
69.08	57.1	58.2
69.10	70.8	62.7
69.42	74.2	64.9
69.45	78.4	66.0
69.66	80.7	67.3
70.11	86.2	69.7
70.31	87.3	70.9
71.50	92.1	77.3
74.74	97.8	85.0
76.73	99.5	89.3

Spectral data

UV-Vis
λmax	? nm
Extinction coefficient, ε	?
IR
Major absorption bands	1055–1000 cm−1
NMR
Proton NMR
Carbon-13 NMR
Other NMR data
MS
Masses of main fragments