Environmental Profile for Propylene Carbonate


United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/600/R-98/068
June 1998
Environmental  Profile for
Propylene Carbonate

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                                                      EPA/600/R-98/068
                                                             June 1998
ENVIRONMENTAL PROFILE FOR PROPYLENE
CARBONATE
                                By

                       Research Triangle Institute
                 Research Triangle Park, NC 27709-2194

                                and

                Science Applications International Corporation
                          Reston, VA 20190
                        Contract No. 68-C6-0027
                            Project Officer:

                           Kenneth R. Stone
                      Sustainable Technology Division
                National Risk Management Research Laboratory
                          Cincinnati, OH 45268
        NATIONAL RISK MANAGEMENT RESEARCH LABORATORY
               OFFICE OF RESEARCH AND DEVELOPMENT
              U S ENVIRONMENTAL PROTECTION AGENCY
                         CINCINNATI, OH 45268
                                                         Printed on Recycled Paper

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                                          Notice

      The information contained in this document has been funded wholly or in part by the U S
  Environmental Protection Agency under Contract 68-C6-0027 to Science Applications    '  '
  Mernational Corporation and through a subcontract from Science Applications International
  Corporation to Research Triangle Institute.  Mention of trade names or commercial products does
  not constitute endorsement or recommendation for use.
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                                       Foreword
    The U. S. Environmental Protection Agency is charged by Congress with protecting the
Nation's land, air, and water resources.  Under a mandate of national environmental laws, the
Agency strives to formulate and implement actions leading to a compatible balance between
human activities and the ability of natural systems to support and nurture life.  To meet this
mandate, EPA's research program is providing data and technical support for solving
environmental problems today and building a science knowledge base necessary to manage our
ecological resources wisely, understand how pollutants affect our health, and prevent or reduce
environmental risks in the future.

    The National Risk Management Research Laboratory is the Agency's center for investigation
of technological and management approaches for reducing risks from threats to human health and
the environment. The focus of the Laboratory's research program is on methods for the
prevention and control of pollution to the air, land, water and subsurface resources; protection of
water quality in public water systems; remediation of contaminated sites and groundwater; and
prevention and control of indoor air pollution.  The goal of this research effort is to catalyze
development  and implementation  of innovative, cost-effective environmental technologies;
develop scientific and engineering information needed by EPA to support regulatory and policy
decisions; and provide technical support and information transfer to ensure effective
implementation of environmental regulations and strategies.

    This publication is a product of the Laboratory's Life Cycle Engineering and Design research
program, an effort to develop life cycle assessment and evaluation tools that can be applied for
improved decision-making by individuals in both the public and private sectors. Life  Cycle
Assessment is a part of the Laboratory's strategic long-term research plan.  This document is
published and made available by EPA's Office of Research and Development to assist the user
community and to link researchers with their clients.
                            E. Timothy Oppelt, Director
                            National Risk Management Research Laboratory
                                                                                      111

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                                      Abstract

    This project is sponsored by the U.S. Department of Defense's (DoD's) Strategic
Environmental Research and Development Program (SERDP) and led by the U.S. Environmental
Protection Agency's (EPA's) Life Cycle Assessment (LCA) Research Team at the National Risk
Management Research Laboratory (NRMRL).  The research effort described in this report was
conducted to support the Life Cycle Engineering and Design (LCED) Program, a cooperative
program of both DoD and EPA. Among the objectives of the LCED is demonstrating the
effectiveness of analytical tools and environmental techniques to reduce impacts to the
environment and costs of operation while maintaining performance standards.  The lessons
learned from LCED projects will be incorporated into  a design guide for DoD process engineers
and designers. Environmental information on propylene carbonate (PC) is required for the
development of the design guide. This report presents information related to the potential
environmental implications of PC.
IV

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                                  Table of Contents
Section
Page
1.0 Introduction	  1-1
    1.1 Goals and Scope of this Research 	  1-2
    1.2 Research Approach	  1-3
    1.3 Report Organization	  1-3

2.0 Production and Use of PC  	2-1
    2.1 Production  	2-2
    2.2 Use	2-2

3.0 Impact Categories	3-1
    3.1 Ecological Impacts  	.3-1
    3.2 Human Health Impacts	3-1

4.0 Data Review	4-1
    4.1 Sources	  4-1
        4.1.1    Literature Search	4-1
        4.1.2    Internet Search 	4-3
    4.2 Physical and Chemical Properties	4-3
    4.3 Environmental Fate and Transport	  4-8
    4.4 Toxicity	;	4-8
        4.4.1    Human Data	4-9
        4.4.2    Laboratory Animal Data	4-9
        4.4.3    Toxicokinetics	4-11

5.0 Impact Assessment	5-1
    5.1 Human Populations at Risk	5-1
    5.2 Natural Resources/Ecosystems  	5-1

6.0 Environmental Regulations	6-1

7.0 Summary  	7-1

8.0 References	8-1

Appendix A: Propylene Carbonate Case Studies	A-l

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                                   List of Tables
3-1 Ecological Impact Categories Related to Chemical and Nonchemical Stressors
    and Resource Depletion 	3-2
3-2 Human Health Impact Categories Related to Chemical and Nonchemical
    Stressors	
3-2
4-1 Literature Search for NMP and PC	4-1
4-2 Specific Topic Literature Search for NMP and PC  	4-2
4-3 Internet Searches for PC Environmental Profile Data 	4-4
4-4 PC Physical and Chemical Properties  	4-6
6-1 Regulatory Information for PC	6-1
VI

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                                    Acronyms

BOD       Biochemical oxygen demand
CAA       Clean Air Act
CARC      Chemical agent-resistant coating
CAS        Chemical Abstracts Service
CERCLA    Comprehensive Environmental Response, Compensation, and Liability Act
COD       Chemical oxygen demand
DoD        U.S. Department of Defense
EPCRA     Emergency Planning and Community Right-to-Know Act
GI          Gastrointestinal tract
LCA        Life cycle assessment
LCED      Life Cycle Engineering and Design Program
MEK       Methyl ethyl ketone
MSDS      Material safety data sheet
NMP       N-methylpyrrolidone
NFPA      National Fire Protection Association
PC          Propylene carbonate
ppm        Parts per million
RCRA      Resource Conservation  and Recovery Act
SARA      Superfimd Amendments and Reauthorization Act
SERDP     Strategic Environmental Research and Development Program
TLV        Threshold limit value
EPA        U.S. Environmental Protection Agency
TOC        Total organic carbon
VOC        Volatile organic compound
°C          Degrees Celsius
°F          Degrees Fahrenheit
                                                                               vn

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                                 1.0 Introduction

      The research effort described in this report was conducted under cooperating programs of
both the Department of Defense (DoD) and the Environmental Protection Agency (EPA).
Among the shared objectives of the cooperators is demonstrating the effectiveness of analytical
tools and environmental techniques to reduce environmental impacts and costs of operation while
maintaining performance standards. This project was sponsored by DoD's Strategic
Environmental Research and Development Program (SERDP) and conducted by EPA's Life
Cycle Assessment Research Team at the National Risk Management Research Laboratory
(NRMRL).

STRATEGIC ENVIRONMENTAL RESEARCH AND DEVELOPMENT PROGRAM
     ©SERDP
            Strategic Environmental Research
               and Development Program
     Improving Mission Readiness Through
          Environmental Research
addition, it is expected that many techniques
public and private sectors.
   SERDP was established 2 years ago in order to
 sponsor cooperative research, development, and
 demonstration activities for environmental risk
 reduction. Funded with DoD resources, SERDP is
 an interagency initiative between DoD, the
 Department of Energy (DOE), and EPA.  SERDP
 seeks to develop environmental solutions that
 improve mission readiness for federal activities. In
that are developed will have applications across the
LIFE CYCLE ASSESSMENT RESEARCH PROGRAM

Since 1990, the NRMRL has been at the forefront in the development of life cycle assessment
(LCA) as a methodology for environmental assessment. In 1994, NRMRL established an LCA
Team to organize individual efforts into a comprehensive research program. The LCA Team
coordinates work in both the public and private sectors with cooperators ranging from members
of industry and academia to federal facility operators and commands. The team has published
project reports and guidance manuals, including Life Cycle Assessment: Inventory Guidelines
and Principles and Life Cycle Design Guidance Manual. The work described in this report is a
part of an expanding program of research in LCA taking place under the direction of NRMRL in
Cincinnati, OH.
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       The research effort described in this report was conducted under the Life Cycle
 Engineering and Design (LCED) program, a cooperative program of both the DoD and EPA.
 Among the objectives of the LCED program is demonstrating the effectiveness of analytical tools
 and environmental techniques to reduce impacts to the environment and costs of operation while
 maintaining performance standards.  To do this, LCED has sponsored three LCA and life cycle-
 based projects at DoD installations:

       •   Propylene Carbonate (PC) Blend 2, a depainting alternative to methyl ethyl ketone (MEK)
       •   Chemical agent-resistant coating (CARC)
       •   GBU-24 energetics model.

       This project is sponsored by DoD's SERDP and by EPA's LCA Research Team at the
 NRMRL.

 1.1    Goals and Scope of this Research

       The overall goal of this research is to document the environmental impacts of PC to assist
 DoD in assessing the life cycle environmental implications of PC and PC-based formulations as
 viable alternative materials, products, and techniques to paint, depaint, and corrosion control
 DoD aircraft, vehicles, and equipment in common applications at federal facilities.

       A life cycle study encompasses the cradle-to-grave stages of a product, process, or
 activity, from the  acquisition of raw materials to the final disposition. Consistent with life cycle
 concepts, the study boundaries for the use of PC in painting and depainting operations include
 the following elements:

       •    Raw materials acquisition
       •    Production of intermediate chemicals and materials
       •    Production of PC
       •    Use of PC
       •    Storage and disposal of residual PC.

 1.2    Research  Approach

       Identifying the life cycle environmental implications of PC in DoD painting and
 depainting operations requires not only a comprehensive search for the use of PC in those
 operations but also a search for information related to the production, use (in other applications),
 and disposal of PC.

       To develop an environmental profile for PC, the following tasks were conducted and
documented:
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       •  Conducted a literature search of PC for all environmental impact information and data
          that can be reasonably acquired

       •  Collected analyses of the environmental impacts of PC as used in painting and
          depainting operations

       •  Contacted responsible individuals in the aerospace industry who .have evaluated PC
          and PC substitutes, as well as those currently using PC

       •  Provided detailed information on the known ecological and human health impacts of
          PC, including occupational health and safety implications of the use of PC in
          aerospace cleaning and depainting operations

       •  Collected relevant case histories on the use of PC for cleaning and depainting
          operations.

1.3    Report Organization

       This report is organized according to the following sections:

       2.0    Production and Use of PC
       3.0    Impact Categories
       4.0    Data Review
       5.0    Impact Assessment
       6.0    Environmental Regulations
       7.0    Summary
       8.0    References.

       Section 2.0 provides background information on PC and presents several case studies
focusing on its use in depainting operations. Key human health and environmental impact
categories are identified in Section 3.0.  Section 4.0 discusses sources of information, physical
and chemical properties, environmental  fate and transport, and the toxicology of PC. Section 5.0
identifies the populations at risk of exposure and summarizes the available data on potential
impacts to natural resources and ecosystems. Current environmental regulations are reviewed in
Section 6.0, and a summary is provided  in Section 7.0.
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                           2.0 Production and Use of PC

       Propylene carbonate is an organic solvent produced by reacting propylene oxide with
carbon dioxide in the presence of a homogeneous catalyst. The process used to manufacture PC
is summarized in Section 2.0 of this report. The relatively low vapor pressure, stability, and high
flash point of PC, along with its solvency characteristics compared to other solvents, make it
suitable for use as a solvent for paints and varnishes, plastics, and epoxides. PC also is used in
the following applications:

       •  Production of fibers and textiles ~ as solvent and softener, specifically in extrusion
          and polymerization into fibers of acrylonitrile and polyamide

       •  Synthetic and natural fabrics finishing (e.g., improving lightfastness, dirt-proofness,
          and mechanical and wrinkle resistance)

       •  Dyeing -- improving the dyeability of fibers

       •  Removal of carbonyl sulfide (COS) and hydrogen sulfide (H2S) and small amounts of
          water from natural and synthesized CO2-rich gas (e.g., ammonia synthesized gas)

       •  Extraction of aromatic hydrocarbons from petroleum fractions and from mixtures
          with aliphatic hydrocarbons

       •  Extraction of metals from acid solutions  (e.g., Bi, Cd, Co, Cu, Au, Fe, Pb, Hg, Mo,
          Pd,Rh,V,W,andZn)

       •  Gel promoter in bentonite-based lubricants

       •  Organic solvent in electrolytes for high-energy density batteries and electrolytic
          capacitors

       •  Personal care agents and cosmetics

       •  Removal of phenols and alcohols from aqueous solutions

       •  Component of cooling agents and brake fluids.

       A life cycle evaluation of PC requires an assessment of all potential impacts associated
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with its production and use. Section 2.1 summarizes the steps involved in the manufacture of
PC, starting with the extraction and processing of natural gas to the manufacture of the final PC
product. Section 2.2 contains summaries of case histories regarding the use of PC in paint and
depainting operations, as well as other applications that provide similar exposure scenarios.

2.1 Production

A description of the process required to manufacture PC is presented in Thomas and
Frankin (1996). Propylenes and other olefins are produced through the thermal cracking of
saturated hydrocarbons such as ethane, propane, naphtha, and other gas oils. Production begins
when hydrocarbons and steam are fed into a cracking furnace. After being heated to
temperatures around 1,000 °C, the cracked products are quenched in heat exchangers. Fuel oil is
separated from the main gas stream in a multistage centrifugal compressor. The main gas stream
then undergoes H2S removal and drying. Propylene is combined with a tert-butyl hydroperoxide
and alcohol mixture at a rate of 2 to 6 moles of propylene per mole of hydroperoxide. This
mixture is reacted to nearly 100 percent conversion of the hydroperoxide over a catalyst usually
made of molybdenum. Propylene and propylene oxide are separated from the product in
distillation columns.

Propylene carbonate is produced by the reaction of propylene oxide with carbon dioxide
over a tetraethyl/ammonium bromide catalyst. The total energy required to produce 1,000 Ib of
PC from raw material acquisition through production equals 14,639,000 Btu for material
resource energy, 10,788,000 Btu for process energy, and 612,000 Btu for transportation energy.
A flow diagram of this process is shown in Figure 1 and on page A-15 in Life Cycle Assessment
for the PC Blend 2 Aircraft Radome Depainter (Thomas and Franklin, 1996).

The composition of paint strippers using PC are defined in U.S. Patent Nos. 5,575,859
and 5,629,277. Patent No. 5,281,723, titled Propylene Carbonate Recovery Process, describes a
method devised to recover a cyclic alkylene carbonate, such as PC, from an effluent stream of
carbonate, water, and polymeric solids. The effluent would be typically processed using a
method in which the cyclic alkylene carbonate removes an organic photoresist material from a
substrate.

2.2 Use

The properties of PC make it suitable for use in painting and depainting and other
industrial stripping and cleaning operations and as a chemical reagent. This section contains
summaries of case studies conducted using PC in painting and depainting operations, as well as
in other applications that entailed similar exposure scenarios to the painting and depainting
operations. Complete case studies are provided in Appendix A. Summaries of case studies are
provided, not the complete reports or project summaries.
2-2