/<
GEPA
United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 2771 1
Research and Development
EPALOO/S9-88~009 May 1988
Project Summary
Findings of the
Chlorofluorocarbon Criemical
Substitutes International
Committee
Thomas P. Nelson
This report presents the findings
of a select international committee of
experts from industry and acedemia
on the subject of chemical
substitutes for fully halogenated
c h l o r o f l u o r o c a r b o n s (CFCs). T h i s
committee, over the course of t w o
meetings, reviewed a n d d i s c u s s e d
data and i n f o r m a t i o n o n c h e m i c a l
alternatives f o r f u l l y h a l o g e n a t e d
CFCs now in use. Also, c o m m i t t e e
members prepared brief reports
highlighting specific areas of
concern.
FC-134a was identified as having
t h e greatest c u r r e n t p o t e n t i a l f o r
r e p l a c i n g CFC-12; s i m i l a r l y , CFC123 c o u l d r e p l a c e CFC-11. T h e
committee acknowledged that, while
there are many other possible
chemical replacements, t h e r e i s a
dearth of i n f o r m a t i o n o n t h e s e
compounds with regard to property
data, toxicity, a n d p e r f o r m a n c e i n
end-use applications.
Investigation of new chemicals to
serve as backup candidate
substitutes if FC-134a and CFC-123
fall short of expectations was
s t r o n g l y r e c o m m e n d e d . S u c h investigations should include a
preliminary screening of chemical,
physical, and thermodynamic p r o p erties; acute toxicity; a n d l i k e l y
atmospheric fate. Finally, several new
c h e m i c a l s were s u g g e s t e d for
examination.
This P r o j e c t S u m m a r y was
developed by EPA’s A i r a n d Energy
E n g i n e e r i n g R e s e a r c h Laboratory,
Research Triangle Park, NC, to announce key findings o f the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
A family of chemicals known as
chlorofluorocarbons (CFCs) has been
implicated in the depletion of the earth’s
stratospheric ozone layer. A number of
adverse health and ecological effects
could result from such depletion. For this
reason a number of strategies or options
for controlling the atmospheric release of
these compounds are being evaluated by
governments and industries worldwide
One promising approach appears to be
the substitution of new, low-ozonedepleting CFCs for those currently
employed in a wide variety of end uses.
There is a need, however, to better
define the requirements for developing
and bringing to market these new
substitutes. To this end, a committee of
authorities of CFC chemistry, production,
toxicology, and marketing was assembled to ascertain the degree of
promise of this approach and what steps
m u s t b e taken b y i n d u s t r y a n d
government to achieve such substitution
in the most efficient and timely manner.
The overall objective of the committee
was to comment on the commercialization potential of newer CFC chemical
substitutes for the s u s p e c t ozone
depleting chemicals: CFC-1 1 ( t r i -
’
chlorofluoromethane), -1 2 (dichlorodifluoromethane), and - 1 13 ( 1 , 1 , 2 trichloro- 1,2,2-trifluoroethane). Specific
objectives included:
Identify the most promising newer
CFC chemical substitutes,
Estimate cost, quantities of chemicals
required, and time for toxicity testing,
application testing, and commercialization of these substitutes,
Specify necessary market and price
preconditions for commercialization,
Recommend research and development tasks to assist commercialization, and
Suggest possible communications
between CFC producers and potential
users regarding research activities
These objectives-were to be addressed
by developing consensus opinions of the
committee members.
The CFC Chemical Substitutes International Committee met twice. At the first
meeting committee members became
more familiar with the CFC environmental issues through direct discussions
with U.S. EPA o f f i c i a l s . Also, the
c o m m i t t e e f o r m u l a t e d their i n i t i a l
thoughts on additional CFC chemical
substitutes, costs, toxicology, and commercialization potentials.
The second meeting, a workshop, was
primarily to complete the definition of the
issues and organize an approach to
addressing the issues. Based on results
of the first meeting, the second meeting
also included interactions with CFC users
from industry. CFC users represented
were a u t o m o b i l e air c o n d i t i o n i n g ,
refrigeration and air conditioning, and
foam insulation board. In addition, F.
Sherwood Rowland ( U n i v e r s i t y of
California-lrvine), one of the originators
of the ozone depletion theory, gave a
presentation of atmospheric chemistry
that focused on current knowledge of
stratospheric chemistry a n d o z o n e
depletion p o t e n t i a l of newer CFC
chemical substitutes.
Deliberations of the committee were
summarized as a formal press release
and as a joint EPAiCommittee Statement.
Also, individual panel members drafted
brief reports on specific aspects of the
issues.
Accomplishments/ResuIts
(Condensed from Executive Summary of Committee Findings, by
Richard Lagow, Committee Chairman)
The most important findings of this
panel were that FC-134a was t h e
primary replacement c a n d i d a t e for
C F C - 1 2 , a n d C F C - 1 2 3 was t h e
primary replacement c a n d i d a t e for
CFC-11. The committee a d v o c a t e d
incentives for increasing the use of
CFC-22 in refrigeration markets and
other applications. Also recommended
was a strong conservation and recycling
program for CFC-113 which is of key
importance as a solvent in cleaning
applications in the electronics industry
and for metal cleaning applications. The
committee identified many other potential
substitutes and recommended further
research on these materials.
Of the many barriers and potential
barriers to availability of appropriate
quantities of alternative CFC and fluorocarbon compounds, the committee concluded that the most basic was the lack
of a worldwide market for such materials.
Such a market can only be created by
government regulations worldwide to
create a demand for such materials. Note
that the chemical manufacturing process
(Swarts reaction and improved versions)
producing the currently marketed CFCs
delivers these products at such a low
price ($1.30-$1.75’kg) that the performance’cost ratio for a variety of
applications is among the highest known
for commercial chemicals. This accounts
for their extraordinarily large market and
widespread use even in applications for
which they are not unique.
The essentially nonflammable and
nontoxic c h a r a c t e r i s t i c s at $ 1 . 3 0 $1.75/kg, which are primary reasons for
use in many applications, cannot be
duplicated at that price. This price
follows from the fact that very inexpensive hydrogen fluoride and chlorocarbons (from petrochemical feedstock
and inexpensive chlorine gas derived
through chloro-alkali c h e m i s t r y of
sodium chloride) are primary feedstocks.
The committee noted that there would be
a ver~y small market or no market for
performance-effective new materials at
e v e n a p r i c e as low as $2.00!lb
($4.40,kg ).
The committee recommends that
governments around the world institute
regulations which would make such new
CFC alternative chemicals economically
viable and establish a market with
suitable incentive for the chemical
industry worldwide to enter the market
with new c o m p o u n d s which h a v e
markedly lower ozone depletion potential
and greenhouse gas effects While some
criticism has been directed toward U.S.
chemical companies along the lines that
it would be unlikely that they would
develop and market such alternatives
without regulatory incentives, in fact, it is
2
very unlikely that users will, without
regulation, be unilaterally willing to pay
higher prices, for they are in competitive
situations and may not be able to sacrifice to become “better world citizens.”
The committee identified the factors that
influence the commercialization timescale
for new compounds as well as the
already known substitutes such as FC134a and CFC-123. Probably the best
overview is that commercial quantities of
such new materials could be available in
a minimum of 5 years and a maximum of
10 years. Analyzing each component of
the timing, the committee found that even
in view of the substantial effort required
for research and development and effort
to design and build commercial facilities,
or alter existing commercial facilities, the
most time-intensive part of the process
of bringing a new material to the market
was the chronic inhalation toxicity testing.
This phase requires up to 4 years and
proceeds in the normal industrial environment after initial market analysis for
the compound appears favorable and
after acute and subchronic testing comes
to a favorable conclusion.
In view of t h e t i m e c r i t i c a l i t y
associated with chronic inhalation studies
and reproductive toxicity studies, some
member of the c o m m i t t e e favored
immediate U.S. government funding of
tier 3 (chronic) toxicity testing of “pure”
samples of obvious substitute candidates,
such as FC-134a and CFC-123, noting
that the $3 million c o s t was very
acceptable if it could cut 6-12 months
off the timescale for commercialization.
It was further noted that such an early
investment could be very advantageous
in starting other new materials down the
path sooner in the event of tier 3 toxicity
failure of such materials as FC-134a
and CFC-123. However, after study, the
consensus of the committee was that tier
3 toxicological testing should best be
done by individual companies or groups
of chemical companies testing together
(for example, through the Chemical
Manufacturers Association in the U.S.).
Each chemical company would want full
control of the toxicological testing,
because they bear the financial liability
and because both the nature and the
level of impurities in the product (which
could also be very significant toxicologically) vary from chemical company
to chemical company and are sensitive to
their exact manufacturing process. Representatives of some companies, however, indicated that they would consider
accepting government subsidies on the
toxicological testing in exchange for
starting dates earlier than normally
prudent in their financial and technical
analysis.
Most members of the committee
concluded, with respect to commercialization t i m e s c a l e s , t h a t a l t h o u g h
substantial research and development
efforts are in place worldwide in the
chemical industry on alternative materials
at the present time, implementation of
regulations on CFC-11, -12, and - 1 13
by governments worldwide would define
the zero point on the timescale. Some
c o m m i t t e e m e m b e r s f e l t that t h e
regulatory strategy and even nuances
within the regulations would have a
significant effect in determining whether
the timescale was more toward the 5 or
more toward the 10 year period for fullscale commercialization. Certainly international agreements could have major
impact in either direction.
With respect to timing, unfavorable
toxicological testing results or manufacturing p r o b l e m s with p r i m a r y
candidates, for example FC-134a and
CFC-123, could cause a significant
delay before other compounds were in
place. It should, however, be clearly
understood that the major reasons the
committee picked FC-134a and CFC123 as leading candidates is that acute
testing for both FC-134a and CFC-123
and subchronic (tiers 1 and 2) testing for
CFC-123 have been completed, and
development work and several patents
for larger scale (but not commercially
viable) syntheses e x i s t for t h e s e
compounds This sets them apart from
the bulk of fluorocarbon, hydrogencontaining f l u o r o c a r b o n , and CFC
materials considered by the committee.
Early analysis b y t h e c o m m i t t e e ,
however, revealed that the toxicological
testing was such a time-limiting factor
that the increase in time for selecting a
material unscreened for toxicology (acute
and subchronic) and perhaps even
without pilot plant experience could be
as little as 6-12 months. As will be
discussed later, there are almost no
toxicological data or technical performance property data on many known
fluorocarbon materials that would appear
to have the physical properties necessary for use as substitutes.
A major contribution of this international committee has been to identify a
large number of predominantly fluorinecontaining compounds of promise for
substitution in applications of currently
manufactured CFCs, particularly CFC1 1 , -12, and -113. These c o m pounds are listed in three categories:
Category A substitute chemicals are
primary candidates chosen to facilitate
rapid implementation of alternatives;
Category B substitute chemicals are
secondary candidates (standby candidates), most of which are hydrogencontaining fluoroethanes and
fluorochloroethanes; and Category C
substitute chemicals are newer, and in
some cases novel, compounds. Category
C has two subclasses: a) hydrogencontaining f l u o r o c a r b o n s , a n d b )
perfluorocarbons and their derivatives.
Note that criteria for selecting many of
the alternative materials were that at least
one hydrogen by available for attack by
OH radicals and/or only fluorine be
present as a halogen in the compound. It
was recognized that non-hydrogencontaining materials may be significant
greenhouse gases.
Of p r i m a r y i m p o r t a n c e i s t h e
committee finding that it will be indeed
possible to develop, at a moderately
higher to substantially higher cost,
substitutes for current CFCs if FC-134a
and CFC-123 fail for some reason. As
stated before, these newer materials may
be only 6-12 months behind if all
committee recommendations are followed. The problem is simply that very
few have been screened even for acute
and subchronic toxicity and, in most
cases, little inore is known of their
physical properties than boiling points
and melting points. Essentially nothing is
known about, for example, their refrigeration performance or solvent properties. In most cases, even basic thermodynamic properties are not known for
these new fluorocarbons. It should be
explained that the reason that new
fluorocarbons and CFCs have not been
screened for application in the CFC
industry is that producers have known for
years, with respect t o the Swarts
technology, that their new materials
would not be performance-cost competitive for such applications. Most are
also manufactured by processes that
would deliver these materials at a minimum of $1 1 .OO,kg and often up to $45
or $65ikg.
The committee listened to presentations from several user industry representatives and came to the conclusion
that, in most applications, new prices for
substitutes could be borne effectively by
the users except in the very cost-competitive, flexible. and rigid foam-blowing
applications where other nonfluorocarbon
materials and other technology could
supplant CFC-11 and -12. It has been
pointed out that CFC-22 would be an
adequate substitute in rigid foarn sheets
but would not have the diffusion stability
for most foam boardstock applications.
3
The committee heard from the users a
strong preference for FC-134a (over
CFC-22) as a “drop-in” for refrigeration a p p l i c a t i o n s ( r e q u i r i n g l i t t l e
modification of air conditioning units) for
mobile air conditioning. This was a
particularly strong preference of the
automobile manufacturers. The committee considered the lack of a known
lubricating oil (which would probably be a
fluorocarbon in this instance) compatible
with FC-134a applications to b e a
problem likely to find a solution within 6
months by any one of several companies.
The committee unanimously felt that
immediate strong measures should be
undertaken by all countries to stimulate
conservation measures which lead to
slower and lower volume releases of
CFCs and believes that accomplishments
can be made in this regard in almost all
applications.
The committee noted that the timescale for implementation of alternative
chemicals which impact the environment
i s 5-8 y e a r s , whereas s i g n i f i c a n t
reductions can be made immediately
through conservation efforts. In view of
the fact that CFC-113 has application in
a broad spectrum of uses and in only
20-30% of these applications is there an
acceptable alternative, the committee
favored an approach to continue the use
of CFC-113. Some committee members
felt that industrial cleaning operations
may not make sufficient attempts to
c o n t r o l the e m i s s i o n of C F C - 1 13
because the price is so low that recovery
is not always economic. Significant
improvements can be made by upgrading old cleaning equipment and improving work practices. Thus, the price could
be artificially increased to m a k e
economically attractive conservation and
recovery from exhaust systems; alternatively, one could legislate against
emissions (considered less effective). At
the same time a vigorous research effort
to synthesize and develop alternative
chemicals to replace CFC-1 13 should
be funded by the federal government.
The committee, some of whom have
consummate knowledge of high-performance chemical fittings, felt that major
advances could be made in retaining
CFCs in mobile air and other air
conditioning applications, and that a cost
for higher pressure fittings of about
$20-$40 per unit was very tolerable
Further, the committee recommends
strongly economic incentives to expand
the use of the already commercially
available CFC-22 (which requires a
higher operating pressure).
The committee found that there is
very little knowledge of the atmospheric
chemistry of new alternative compounds
other than generalizations which apply to
groups The committee has found even
less knowledge concerning the ultimate
fate in the environment of such species
as FC-134a It is estimated that hydrochloric and hydrofluoric acids contribute
to acid rain but are orders of magnitude
less significant than sulfuric acid Little is
known about the effect on the atmosphere and environment of products
such as srnall concentrations of t r i fluoroacetic acid or partially fluorinated
acetic a c i d a n d i f they w i l l b e
established in fact, as breakdown products
The committee has determined that it
i s absoiutely n e c e s s a r y that U S
government funds be spent (and funding
encouraged worldwide) at a minimum
level of $3 million per year to support
research in the academic small industry
and industrial sectors focused on a
number of these extremely important
problems in areas where knowledge is
e s s e n t i a l I y lac k i n g G o v e r n m e n t
regulations which were designed to
effectively reduce CFC-1 1 and -12
over a period of 10 years will be made at
very high risk, and "safe ' effective
alternatives may not be available on a
timescale to meet society's demands
without this relatively modest funding
effort The most important research
needs are
0 Atmospheric chemistry studies for
specific new chemicals funded by a
separate budget within the EPA from
general atmospheric studies,
0 Synthesizing new materials to be
evaluated for alternative chemical
applications
0 Evaluating
p r o p e r t i e s of n e w
chemicals for various applications and
o b t a i n i n g basic t h e r m o d y n a m i c
properties for such materials, and
0 Determining
the
ultimate
environmental fate of alternative
fluorocarbon materials such as FC134a and CFC-123
In general, there is a pressing need to
evaluate at least 10 or so of the most
likely alternative materials from the
n o n t r a d i t i o n a l a r e a s of C F C a n d
fluorocarbon chemistry for applications
The c o m m i t t e e also strongly r e c ommended that at least 20 of the more
speculative alternatives be prepared in
sufficient amounts and purity for acute
and subchronic toxicity testing It i s
further recommended that the committee
replace yearly any of those backup
compounds which fall out of contention
with others so that a worldwide pool of
about 10-20 backup materials will be
available Overall the committee takes
the view that the level of knowledge
outside of Swarts CFC technology for
p r o d u c t i o n of materials for t h e s e
applications critical to societal needs is
almost nonexistent and certainly no more
than in the embryonic stage Therefore,
the need for funding substantial amounts
of research up to the date where
important atmospheric problems (e g ,
ozone depletion and the greenhouse
effect) are solved satisfactorily cannot be
overemphasized
Thomas P. Nelson 1s with Radian Corporation, P.O. Box 9948. Austin TX 78720.
N. Dean Smith is the €PA Project Officer (see below).
The complete report. entitled "Findings o f the Chlorofluorocarbon Chemical
Substitutes International Committee, (Order No. P 6 88- 195 664!AS;
Cost: $19.95, subject to change) will b e available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22 16 1
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S.Environmental Protection Agency
Research Triangle Park NC 2771 1
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA 600, S9-88 009
.
.
.
.
Q Li.? GOVERNMENT PRINTING OFFICE IYXX--~54X.OI:i X:!Jii