Heptane

142-82-5

Solvent.

Colorless liquid (HSDB 2002).

Gasoline-like odor (HSDB 2002).

Relative volatility (nBuAc=1) = 3.62

Based upon a water solubility of 2.93 mg/l and a vapor pressure 
of 45.8 mmHg at 25 °C, the Henry's Law constant for n-heptane 
has been calculated to be 2.06 atmxm3/mole. 
This value of 
Henry's Law constant indicates estremely rabid volatilization 
from environmental waters. 
The volatilization half-life from a 
model river (1 meter deep flowing 1 m/sec with a wind speed of 
3 m/sec) has been estimated to be 2.9 hr. 
The volatilization 
half-life from a model pond, which considers the effect of 
adsorption, has been estimated to be 13 days (HSDB 2002).

Based on a water solubility of 2.93 mg/l and a log Kow of 4.66, 
the Koc of n-heptane has been calculated to range from 2400 to 
8100 from various regression-derived equations. 
These Koc 
values indicate n-heptane will be slightly mobile to immobile 
in soils (HSDB 2002).

Based on data for the structurally similar n-hexane and 
iso-octane, n-heptane is not expected to adsorb UV light in 
environmentally significant range >290 nm. 
Therefore n-heptane 
probably will not undergo direct photolysis in the environment. 

The rate constant for the vapor phase reaction of n-heptane 
with photochemicaly produced hydroxyl radicals was measured to 
be 7.18x10-10 cm3/molecule-sec at 26 °C which corresponds to an 
atmospheric half-life about 2.2 days at an atmospheric concn of 
5x10+5 radicals per cm3. 
At 27 °C the rate constant and half 
life were reported to be 8.5x10-12 cm3/sec and 1.9 days 
respectively (HSDB 2002).

The theoretical oxygen demand of benzene activated sludge for 
n-heptane was 0.7, 4.3 and 23.4% after 6, 24 and 72 hr 
respectively. 
The average theoretical biological oxygen demand 
of trials for n-heptane was 28, 63, 70 and 70% after 2, 5, 10 
and 20 days, respectively (HSDB 2002).

Based upon a water solubility of 2.93 mg/l at 25 °C and log Kow 
of 4.66, the bioconcentration factor (log BCF) for n-heptane 
has been calculateed to be 2.53 and 3.31, respectively, from 
recommended regression-derived equations. 
These BCF values 
indicate bioconcentration may be important (HSDB 2002).