Chemical Properties of Isoprene (CAS 78-79-5)

InChI

InChI=1S/C5H8/c1-4-5(2)3/h4H,1-2H2,3H3

InChI Key

RRHGJUQNOFWUDK-UHFFFAOYSA-N

Formula

C5H8

SMILES

C=CC(=C)C

Molecular Weight¹

68.12

CAS

78-79-5

Other Names

• 1,3-Butadiene, 2-methyl-
• 2-Methyl-1,3-butadiene
• 2-Methylbuta-1,3-diene
• 2-Methylbutadiene
• 3-Methyl-1,3-butadiene
• CH2=C(CH3)CH=CH2
• Isopentadiene
• NSC 9237
• «beta»-Methylbivinyl
• «beta»-Methylbivinyl

• PAff : Proton affinity (kJ/mol).
• BasG : Gas basicity (kJ/mol).
• Δ_cH°_gas : Standard gas enthalpy of combustion (kJ/mol).
• Δ_cH°_liquid : Standard liquid enthalpy of combustion (kJ/mol).
• C_p,gas : Ideal gas heat capacity (J/mol×K).
• C_p,liquid : Liquid phase heat capacity (J/mol×K).
• Δ_fG° : Standard Gibbs free energy of formation (kJ/mol).
• Δ_fH°_gas : Enthalpy of formation at standard conditions (kJ/mol).
• Δ_fusH° : Enthalpy of fusion at standard conditions (kJ/mol).
• Δ_fusH : Enthalpy of fusion at a given temperature (kJ/mol).
• Δ_vapH° : Enthalpy of vaporization at standard conditions (kJ/mol).
• Δ_vapH : Enthalpy of vaporization at a given temperature (kJ/mol).
• IE : Ionization energy (eV).
• log₁₀WS : Log10 of Water solubility in mol/l.
• logP_oct/wat : Octanol/Water partition coefficient.
• McVol : McGowan's characteristic volume (ml/mol).
• P_c : Critical Pressure (kPa).
• P_vap : Vapor pressure (kPa).
• n₀ : Refractive Index.
• I_np : Non-polar retention indices.
• I : Polar retention indices.
• Δ_fusS : Entropy of fusion at a given temperature (J/mol×K).
• S°_gas : Molar entropy at standard conditions (J/mol×K).
• S°_liquid : Liquid phase molar entropy at standard conditions (J/mol×K).
• T_boil : Normal Boiling Point Temperature (K).
• T_c : Critical Temperature (K).
• T_fus : Normal melting (fusion) point (K).
• T_triple : Triple Point Temperature (K).
• V_c : Critical Volume (m³/kmol).
• ¹: Molecular weight from the IUPAC atomic weights tables.

Physical Properties

Property	Value	Unit	Source
PAff	826.40	kJ/mol	NIST
BasG	797.60	kJ/mol	NIST
ΔcH°gas	-3186.60 ± 0.96	kJ/mol	NIST
ΔcH°liquid	-3158.20 ± 1.60	kJ/mol	NIST
ΔfG°	158.35	kJ/mol	Joback Calculated Property
ΔfH°gas	75.70 ± 1.00	kJ/mol	NIST
ΔfusH°	4.84	kJ/mol	Joback Calculated Property
ΔvapH°	[26.40; 26.80]	kJ/mol
ΔvapH°	26.40	kJ/mol	NIST
ΔvapH°	26.80 ± 0.30	kJ/mol	NIST
IE	[8.84; 9.04]	eV
IE	8.86 ± 0.02	eV	NIST
IE	8.85 ± 0.02	eV	NIST
IE	8.85	eV	NIST
IE	8.90 ± 0.10	eV	NIST
IE	8.89	eV	NIST
IE	8.85 ± 0.01	eV	NIST
IE	8.84 ± 0.01	eV	NIST
IE	8.85	eV	NIST
IE	8.85	eV	NIST
IE	8.87	eV	NIST
IE	Outlier 9.04	eV	NIST
log10WS	[-2.03; -2.03]
log10WS	-2.03		Aq. Sol...
log10WS	-2.03		Estimat...
logPoct/wat	1.748		Crippen Calculated Property
McVol	72.710	ml/mol	McGowan Calculated Property
Pc	3862.67	kPa	Joback Calculated Property
Inp	[491.50; 520.00]
Inp	496.00		NIST
Inp	508.00		NIST
Inp	506.00		NIST
Inp	499.00		NIST
Inp	497.50		NIST
Inp	507.00		NIST
Inp	497.60		NIST
Inp	Outlier 491.50		NIST
Inp	495.70		NIST
Inp	496.00		NIST
Inp	497.00		NIST
Inp	501.00		NIST
Inp	501.00		NIST
Inp	507.00		NIST
Inp	499.00		NIST
Inp	Outlier 514.00		NIST
Inp	511.00		NIST
Inp	506.00		NIST
Inp	504.00		NIST
Inp	502.20		NIST
Inp	504.00		NIST
Inp	Outlier 520.00		NIST
Inp	497.00		NIST
Inp	504.00		NIST
Inp	505.00		NIST
Inp	502.95		NIST
Inp	500.00		NIST
Inp	502.00		NIST
Inp	503.00		NIST
Inp	504.00		NIST
Inp	506.00		NIST
Inp	502.00		NIST
Inp	503.00		NIST
Inp	504.00		NIST
Inp	503.00		NIST
Inp	503.00		NIST
Inp	504.00		NIST
Inp	506.00		NIST
Inp	504.00		NIST
Inp	503.00		NIST
I	[602.00; 633.00]
I	624.00		NIST
I	602.00		NIST
I	633.00		NIST
I	633.00		NIST
S°gas	314.76	J/mol×K	NIST
S°liquid	[228.28; 229.30]	J/mol×K
S°liquid	228.28	J/mol×K	NIST
S°liquid	229.20	J/mol×K	NIST
S°liquid	229.30	J/mol×K	NIST
Tboil	[306.00; 309.65]	K
Tboil	307.30	K	NIST
Tboil	307.20 ± 2.00	K	NIST
Tboil	307.20 ± 1.00	K	NIST
Tboil	307.30 ± 0.50	K	NIST
Tboil	307.00 ± 1.50	K	NIST
Tboil	306.00 ± 2.00	K	NIST
Tboil	307.00 ± 0.60	K	NIST
Tboil	307.20 ± 0.50	K	NIST
Tboil	307.50 ± 0.50	K	NIST
Tboil	307.02 ± 0.60	K	NIST
Tboil	307.22 ± 0.20	K	NIST
Tboil	307.55 ± 1.50	K	NIST
Tboil	306.40 ± 1.00	K	NIST
Tboil	306.30 ± 1.00	K	NIST
Tboil	307.30 ± 0.50	K	NIST
Tboil	Outlier 309.65 ± 1.00	K	NIST
Tboil	309.00 ± 2.00	K	NIST
Tc	480.20	K	Joback Calculated Property
Tfus	[126.40; 153.00]	K
Tfus	127.18	K	Aq. Sol...
Tfus	127.18 ± 0.05	K	NIST
Tfus	127.20 ± 0.03	K	NIST
Tfus	127.10 ± 0.40	K	NIST
Tfus	126.96 ± 0.20	K	NIST
Tfus	127.01 ± 0.10	K	NIST
Tfus	126.40 ± 0.40	K	NIST
Tfus	Outlier 153.00 ± 10.00	K	NIST
Ttriple	[126.40; 127.27]	K
Ttriple	127.27 ± 0.05	K	NIST
Ttriple	126.40 ± 0.20	K	NIST
Vc	0.279	m3/kmol	Joback Calculated Property

Temperature Dependent Properties

Property	Value	Unit	Temperature (K)	Source
Cp,gas	[101.90; 144.42]	J/mol×K	[307.04; 480.20]
T(K) Ideal gas heat capacity (J/mol×K) 100 110 120 130 140 350 400 450
Cp,gas	101.90	J/mol×K	307.04	Joback Calculated Property
Cp,gas	109.82	J/mol×K	335.90	Joback Calculated Property
Cp,gas	117.40	J/mol×K	364.76	Joback Calculated Property
Cp,gas	124.63	J/mol×K	393.62	Joback Calculated Property
Cp,gas	131.54	J/mol×K	422.48	Joback Calculated Property
Cp,gas	138.13	J/mol×K	451.34	Joback Calculated Property
Cp,gas	144.42	J/mol×K	480.20	Joback Calculated Property
Cp,liquid	[151.08; 152.60]	J/mol×K	[298.15; 298.20]
Cp,liquid	151.08	J/mol×K	298.15	NIST
Cp,liquid	152.50	J/mol×K	298.15	NIST
Cp,liquid	152.60	J/mol×K	298.20	NIST
ΔfusH	[4.83; 4.92]	kJ/mol	[126.40; 127.30]
T(K) Enthalpy of fusion at a given temperature (kJ/mol) 4.84 4.86 4.88 4.9 4.92 126.5 127
ΔfusH	4.83	kJ/mol	126.40	NIST
ΔfusH	4.83	kJ/mol	126.40	NIST
ΔfusH	4.92	kJ/mol	127.27	NIST
ΔfusH	4.92	kJ/mol	127.30	NIST
ΔfusH	4.92	kJ/mol	127.30	NIST
ΔvapH	[25.80; 31.50]	kJ/mol	[225.50; 307.20]
T(K) Enthalpy of vaporization at a given temperature (kJ/mol) 26 27 28 29 30 31 32 240 260 280 300
ΔvapH	31.50	kJ/mol	225.50	NIST
ΔvapH	29.40	kJ/mol	237.50	NIST
ΔvapH	28.30	kJ/mol	285.00	NIST
ΔvapH	27.40	kJ/mol	288.00	NIST
ΔvapH	27.30	kJ/mol	299.00	NIST
ΔvapH	25.80	kJ/mol	307.20	NIST
n0	1.42180		293.15	Isobari...
ΔfusS	[38.21; 38.69]	J/mol×K	[126.40; 127.27]
ΔfusS	38.21	J/mol×K	126.40	NIST
ΔfusS	38.21	J/mol×K	126.40	NIST
ΔfusS	38.69	J/mol×K	127.27	NIST

Correlations

Property	Value	Unit	Temperature (K)	Source
Pvap	[10.86; 3761.79]	kPa	[255.15; 483.30]	KDB Vap...
Equation			ln(Pvp) = A + B/T + C*ln(T) + D*T^2
Coefficient A			7.59285e+01
Coefficient B			-5.60831e+03
Coefficient C			-9.40749e+00
Coefficient D			8.78776e-06
Temperature range, min.			255.15
Temperature range, max.			483.30
T(K) Vapor pressure (kPa) 0 500 1000 1500 2000 2500 3000 3500 4000 300 400
Pvap	10.86	kPa	255.15	Calculated Property
Pvap	36.60	kPa	280.50	Calculated Property
Pvap	96.91	kPa	305.85	Calculated Property
Pvap	214.89	kPa	331.20	Calculated Property
Pvap	417.14	kPa	356.55	Calculated Property
Pvap	732.07	kPa	381.90	Calculated Property
Pvap	1189.37	kPa	407.25	Calculated Property
Pvap	1821.05	kPa	432.60	Calculated Property
Pvap	2663.69	kPa	457.95	Calculated Property
Pvap	3761.79	kPa	483.30	Calculated Property

Similar Compounds

Find more compounds similar to Isoprene.

Mixtures

• Isoprene + Cyclopentane
• Isoprene + 2-Butene, 2-methyl-
• Isoprene + Cyclopentene

Sources

• KDB Vapor Pressure Data
• Crippen Method
• Isobaric Vapor Liquid Equilibrium for Nine Binary Systems of Cracking C5 Fraction at 250 kPa
• Joback Method
• KDB
• Aqueous Solubility Prediction Method
• Estimated Solubility Method
• McGowan Method
• NIST Webbook

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Outlier This icon means that the value is more than 2 standard deviations away from the property mean.