1,4-Dioxane Chemistry, Uses, and Occurrence - Environmental Investigation and Remediation - page 78

heat

O

H 2 C CH 2

CH 2

HO

OH

+ H 2 SO 4

CH 2

H 2 C CH 2

Sulfuric
acid

Ethylene glycol

O

H 2 O
Dehydration

1,4-Dioxane

FIGURE 2.3 Conceptual representation of a common 1,4-dioxane production method involving the dehy-
dration and ring closure of ethylene glycol with a strong acid catalyst (sulfuric acid).

2.2 HISTORY OF 1,4-DIOXANE PRODUCTION
1,4 -D ioxa ne is pro duc e d f rom et hylene g lycol. T he most com mon ly use d pro c ess, show n i n Fig u r e 2 .3,
involves heating ethylene glycol to 160°C and reacting it with concentrated sulfuric acid under a
vacuum. 1,4-Dioxane forms when a catalyst—usually a strong acid—drives off water from ethylene
glycol and reconi gures it to a ring structure. The reaction may have a 90% yield and is usually
carried out on a continuous basis. The 1,4-dioxane/water-vapor azeotrope is collected and distilled
with an acid trap to remove water and sulfuric acid (ATSDR, 2005; Surprenant, 2005 ). 1,4-Dioxane
and its derivatives can also be produced with ethylene oxide as feedstock. A catalysis reaction on an
acid ion exchange resin or on zeolites will dimerize ethylene oxide to diethylene dioxide, that is,
1,4-dioxane. Another method produces 1,4-dioxane and substitutes dioxane derivatives from
bis(2-chloroethyl)ether (also called 2-chloro-2 -hydroxyethyl ether) by heating and treating with a

20% sodium hydroxide reactant (ATSDR, 2005; Surprenant, 2005).

′

2.2.1 1,4-D IOXANE P RODUCTION FOR C OMMERCIAL A PPLICATIONS
1,4-Dioxane was i rst produced for commercial sale and use in 1929 (ATSDR, 2004). 1,4-Dioxane
could be purchased in New York for $0.50/lb in 1929 (American Chemical Society, 1929); the price
lowered to $0.25/lb by 1934 (American Chemical Society, 1935). The United States began larger-
scale production of 1,4-dioxane in 1951 (National Cancer Institute, 1985). A company in Japan
began production in 1958 (Osaka Organic Chemical Industry, Ltd., 2006). The largest demand for
1,4-dioxane arose in the late 1950s and early 1960s with its use in stabilizing methyl chloroform.
Thereafter, 1,4-dioxane production closely tracked the production of methyl chloroform ( Figure 2.4 ).
In 1985, the worldwide production of 1,4-dioxane was estimated at 30.8 million pounds
(15,400 tons or 14,000 metric tons) (Surprenant, 2005). Production in the United States in 1985 was
estimated at 25 million pounds (12,500 tons or 11,300 metric tons). In the same year, the total
methyl chloroform consumption in the United States—accounting for the total U.S. production,
imports, and exports—was 450,000 tons. The approximate ratio of 1,4-dioxane production for
domestic consumption to the comparable i gure for methyl chloroform is about 3%. In the mid-
1980s, about 90% of the 1,4-dioxane produced annually was used to stabilize methyl chloroform
(National Cancer Institute, 1985). By 1995, the year in which ozone-depleting substance regulations
severely curtailed the use of methyl chloroform, the production of 1,4-dioxane decreased to 22 million
pounds (11,000 tons or 10,000 metric tons) (European Chemicals Bureau, 2002). The U.S.
Environmental Protection Agency (USEPA) reports that the range of 1,4-dioxane production was
from 10 to 50 million pounds between 1986 and the early 1990s; after 1994, production ranged from
1 to 10 million pounds (USEPA, 2008), as shown in Figure 2.4.