Historical Use of Chlorinated Solvents and Their Stabilizing Compounds - Environmental Investigation and Remediation - page 62

compound-specii c parameter, K oc . Tables 1.31 through 1.34 contrast the K oc values for stabilizers
with their host solvents, to predict which stabilizers would be lost to carbon i ltration. These tables
are also useful for predicting the fate of stabilizers in contact with soil organic matter as they
migrate through the soil proi le following a release. Fate and transport of stabilizers in the environ-
ment are described in detail in Chapter 3.
In addition to carbon i ltration, physical i ltration was also used to remove soil from solvents in
degreasing, cold cleaning, dry cleaning, and solvent reclamation operations. Conventional i lters,
made of paper and other i brous mater ia ls, were use d to remove pa r t icles dow n to 0.5 m in diameter.

Solvent-resistant polymeric membranes were used to remove particles smaller than 1

μ

m. These
i lters remove high-molecular-weight matter, such as dissolved oil and grease, but allow molecules
smaller than 150-200 Da (daltons) to pass through (Howell and Tarrer, 1994). Membrane separation
technology in solvent purii cation can remove stabilizers with higher molecular weights, such as
triethanolamine, and impurities with higher molecular weights, such as perchloroethylene and
carbon tetrachloride.

μ

1.2.7.5 Thermal Stability
Stabilizers added to chlorinated solvents must be stable within the operating temperature range of
the process for which the solvent is used. Stabilizers should be immune to pyrolysis at temperatures
below the boiling point of the solvent and below the temperatures used for distilling solvents in
reclamation processes. Solvent boiling temperatures may become slightly elevated when oily waste
accumulates in the boiling sump; higher temperatures may be reached where metal i nes build up

TABLE 1.31
Organic Carbon Partition Coeffi cient Contrasts for Stabilizers with Methyl Chloroform

K oc Ratio
(Stabilizer:Solvent) Stabilizer log K oc Rank

Retained in Filter
n -Methyl pyrrole

4 54.95 1

Decreasing Retention in Carbon Filter
Resorcinol 1.8 0.35 2

sec- Butyl alcohol 1.7 0.28 3

tert- Butyl alcohol 1.57 0.20 4

Toluene 1.56 0.20 5

2-Butanone 1.5 0.17 6

Nitroethane 1.48 0.17 7

1,4-Dioxane 1.23 0.09 8

Acetonitrile 1.2 0.09 9

1,3-Dioxolane 1.17 0.08 10

Isobutyl alcohol 0.95 0.05 11

1,2-Butylene oxide 0.90 0.04 12

2-Methyl-3-butyn-2-ol 0.54 0.02 13

t -Amyl alcohol 0.46 0.02 14

Nitromethane 0.28 0.01 15

Trioxane −1.6 0.00 16

Source: See Appendix 2 for a tabulation of physical and chemical properties of solvent-stabilizer compounds with full
citations.
Note: For methyl chloroform, log K oc = 2.26.