Perfluorinated Chemistries: - PowerPoint PPT Presentation

Perfluorinated Chemistries:

Technologies and Alternatives

Richard Holt

BIAC

• Numerous alternatives
• Time constraints
• Competitive considerations
• Anti-trust considerations
• Knowledge base – proprietary uses and formulations

• Surfactants
• From >6-Carbon to 4-Carbon-based sulfonate chemistry
• From >8-Carbon to <6-Carbon Fluorotelomer chemistry
• From 8- and 9-Carbon Perfluorocarboxylate Polymerization Aids (PFOA/PFNA) to certain Mono- and Poly-perfluoroethers or other substances
• Surface Modification Polymers
• From >6-Carbon to 4-Carbon-based sulfonate chemistry
• From >8-Carbon to <6-Carbon Fluorotelomer chemistry
• Requires cooperation from manufacturers in a wide range of downstream industries, from consumer product manufacturers to defense and aerospace industries

• In Kind: Fluorinated
• C6: Fluorotelomer-based six fluorinated carbon functionality compounds
• C4: Electrochemical fluorination-based four fluorinated carbon functionality compounds - Perfluorobutane sulfonate (PFBS)
• Mono- and poly-fluorinated ether functionality compounds (e.g., CF3 or C2F5 fluoroalkyl polyethers)
• Fluorinated oxetanes
• Other fluorinated polymers

• Not-in-kind
• Hydrocarbons
• Propylated naphthalenes or biphenyls
• Fatty alcohol polyglycol ether sulfate
• Sulfosuccinate
• Hydrocarbon surfactants
• Naphthalene derivatives
• Siloxanes and silicone polymers

Do The Alternatives Work?

The transition from the current highly effective products to suitable alternatives has been accomplished with the following criteria as guidelines:

• Efficacy of use be maintained
• Reduced biopersistence
• Minimization of customer disruption
• Value in use be maintained
• Critical societal uses are not compromised
• Reduction of the environmental footprint

• Non-fluorinated alternatives, such as different hydrocarbon surfactants and silicone products, have been identified… however, in most cases or at least in larger application areas, other fluorinated compounds are used instead…. non-fluorinated alternatives do not work as well, especially in situations, where extreme low surface tension is needed (Danish EPA, 2006). 

C-6 and C-4 chemistries adequately meet the criteria for replacement of most current C-8 and higher homologue uses.

• US EPA is reviewing substitutes for Long Chain PFCs as part of its review process for new chemicals under EPA's New Chemical Program

– Ongoing since 2000

– Consistent with the approaches to alternatives encouraged under the PFOA Stewardship Program

– Over 100 alternatives of various types have been received and reviewed by EPA

• More information at http://epa.gov/oppt/pfoa/pubs/altnewchems.html

* EPA presentation April 19, 2010 (Las Vegas, Nevada USA) and various other industry and trade meetings

Fluorinated Products - Technology

Synthesis Origin

• Electrochemical fluorination (ECF)
• Fluorotelomer
• Fluoro(poly)ether
• Fluorinated oxetane

Unique Properties

• Lower aqueous surface tension = wetting power
• the power to spread and coat surfaces
• Function at very low concentrations
• 100 parts per million
• Work well in tandem with hydrocarbon and silicone surfactants
• Unique function in “dynamic” systems

F(CF2)nSO2N(R)CH2CH2OH

Perfluoroalkyl sulfonamido ethanol

Electrochemical Fluorination (ECF) Products

H(CH2)nSH aliphatic mercaptan

An Example of New Products based on n=4

Perfluorobutane sulfonyl (PFBS)

Chemistry

C4F9SO2 - R

HF, e-

F(CF2)nSO2F

F(CF2)nSO3X

Sulfonyl fluoride

PFDS n = 10

PFOS n = 8

PFHxS n = 6

PFBS n = 4

PFBS = C4F9SO3-

Potential degradation product

Fluorotelomer-based Products

CF2=CF2(TFE)

F(CF2)6I

Perfluoroalkyl Iodide

An Example of New Products based on n = 6

Phosphate

Ethoxylate

Betaine

F(CF2)6CH2CH2I

Fluorotelomer Iodide

F(CF2)6CH2CH2OH

Fluorotelomer Alcohol

Potential degradation product

PFHxA, perfluorohexanoate: F(CF2)5CO2-

(ng/mL)

(hr)

Pharmacokinetics in Monkey: PFBS and PFHxA

PFBS

PFHxA

Serum concentration of PFHxA or PFBS after

single intravenous administration

Fluoropolyether (PFPE) Surfactants

• PFPE-diol raw material
• MW 1500 AMU; Made by photooxidation including tetrafluoroethylene (TFE)
• Phosphate ammonium salt
• Carboxylate ammonium salt
• Ethoxylateddiol

HOCH2-CF2O-(CF2O)m-(CF2CF2O)n-CF2CH2OH

• Alternatives exist for nearly all current uses
• There are some uses still for which adequate replacements have not yet been identified
• Alternatives with a shorter fluorinated alkyl chain are still environmentally persistent but not bioaccumulative
• The C4 sulfonate and the C6 carboxylate have shown different pharmacokinetics (shorter half-life) and lower toxicity than PFOA and PFOS
• Non-fluorinated alternatives do not work as well

• PFOS and PFOA are some of the most studied chemicals, therefore ...
• Alternatives will almost always have less supporting data, however ...
• Adequate supporting data have been submitted to obtain regulatory approval, generally subject to requirements to submit additional data to robustly define hazard and exposure profiles.
• Good business move for the future!