Science - USA (2022-02-04)

Evichet al.,Science 375 , eabg9065 (2022) 4 February 2022 3 of 14

Oligomerization Direct fluorination

Non-PFAS

base chemicals

HF F^2 CTFE CF

=CFCl (^2) VDF
CH
=CF 2
2
HCFC-22CHClF
2
TFE

CF^2
=CF
2
HCFC-133aCF
CH 3
Cl 2
HFC-134aCF
CH 3
F 2
HCFC-123a
CF
CHCl 3
(^2)
HCFC-124CF
CHClF 3
hydrofluorocarbon (HFC)-125CF
CHF 3
2
hydrochlorofluoroolefin (HCFO)-1233xfCF
CCl=CH 3
(^2)
hydrochlorofluorocarbon (HCFC)-244bbCF
3
CFCl
CH
(^3)
hydrofluoroolefin (HFO)-1234yfCF
3
CF=CH
2
perfluoroalkyl-
tert
-amines
(Cn
F2n+1
)N^3
benzotrifluorides
, e.g. benzotrifluoride, 4-chloro- and 2,4-dichloro benzotrifluorides, 1,3-
bis(trifluoromethyl) and 1,4-bis(trifluoromethyl)benzenes, 4-(trifluoromethyl)benzoyl fluoride
Fluometuron
Other side-chain fluorinated aromatics,
e.g. fluoxetine, flumetramide, fenfluramine, flufenamic acid, niflumic acid, fludorex, triflupromazine, fluphenazine; trifluralin, profluralin, benfluralin, fluorodifen, acidfluorfen, fluvalinate, norflurazon
perfluoroalkanoyl fluorides (PACFs)Cn
F2n+1
C(O)F
perfluoroalkylamides (PFAMs),
e.g.,
Cn
F2n+1
C(O)NH
2
Cn
F2n+1
CH
OH 2
Cn
F2n+1
CH
-R 2
PACF-based derivatives, e.g., C^5
F^11
C(O)NH(CH
) 32
Si(OCH
) 33
perfluoroalkanesulfonyl fluorides (PASFs) Cn
F2n+1
S(O)
F 2
perfluoroalkanesulfonic acids (PFSAs) Cn
F2n+1
S(O)
OH 2
perfluoroalkanesulfonamides (
xFASAs)
Cn
F2n+1
S(O)
NH-R 2
Other PASF-based derivatives
**
Cn
F2n+1
S(O)
-R 2
(see Part B)
perfluoroalkanesCn
F2n+2
polyvinylidene fluoride (PVDF)(CH
2
CF
) 2 n
polychlorotrifluoroethylene (PCTFE)(CF
2
CFCl)
n
hexafluoropropylene (HFP)

CF
CF=CF 3
2
fluorinated ethylene propylene (FEP)(CF
2
CF
) 2 m
[C(CF
)F 3
CF
] 2 n
terpolymer of TFE, HFP and VDF (THV)
(CF
CF 2
) 2 m
[CF
C(CF 2
)F] 3
n
(CH
CF 2
) 2 p
HFP oxide (HFPO)CF
CFCF 3
O 2
Fomblin® Z FluidsCF
O[CF 3
CF(CF 2
)O] 3
(CFm
O) 2
[CF(CFn
)O] 3
CFp
X 2
hexafluoroacetoneFCC(O)CF^3
3
[(F
C) 3
CF] 2
2
C=CF(CF
) 3
OBS[(CF
) 32
CF]
C=C(CF 2
)(OC 3
H 6
SO 4
Na) 3
perfluoropropylvinyl ether (PPVE)CF
CF 3
CF 2
OCF=CF 2
2
HFPO dimer acids (HFPO-DA)CF
CF 3
CF 2
OCF(CF 2
)C(O)OH 3
Krytox® Fluids
, e.g.
CF
CF 3
CF 2
O[CF(CF 2
)CF 3
O] 2
CF(CFn
)C(O)F 3
hexafluoroisobutene(F^3
C)^2
C=CH
2
pentafluoroethyl iodide (PFEI)C^2
FI^5
perfluoroalkyl iodides (PFAIs)

C^2
F(CF^5
CF 2
) 2 n
I
n:2 fluorotelomer iodides (n:2 FTIs)
and
their derivatives
**
Cn
F2n+1
CH
CH 2
I and C 2
Fn
2n+1
CH
CH 2
2
(^)
(^)
(^) R

(see Part B)

semifluorinated alkanes (SFAs)Cn F2n+1

Cm

H2m+1

perfluoroalkyl phosphonic acids (PFPAs) Cn F2n+1

P(O)(OH)

2

polytetrafluoroethylene (PTFE)(CF

2

CF

) 2 n

perfluoroalkyl bromides (PFABrs)Cn F2n+1

Br

ethylene tetrafluoroethylene (ETFE)(CF

2

CF

) 2 n

(CH

2 CH

) 2 m

Fomblin® Y FluidsXCF

O(CF 2

O) 2

(Cm

F 24 O)

CFn

X 2

perfluoroalkyl di-iodidesI(CF

CF 2

) 2 n I

perfluoroalkyl dicarboxylic acids (PFdiCAs) HOOC(CF

CF 2

) 2 n COOH

F^2 C=CF

O

CF

CF(CF 2

) 3

O

CF

CF 2

SO 2

F 2

Nafion(CF

CF 2

) 2 m

(CF

CF) 2

n OCF

CF(CF 2

)OCF 3

CF 2

SO 2

F 2

perfluoroalkyl phosphinic acids (PFPIAs) (C

Fn2n+1

)P(O)OH^2

perfluoroalkoxy alkane (PFA)

, e.g.

(CF

2

CF

) 2 n

[C(OCF

CF 2

)F 3

CF

] 2 m

perfluoroalkylcarboxylic acids (PFCAs)

*

Cn F2n+1

C(O)OH

A

xFASEs Cn F2n+1

S(O)

N(R)CH 2

CH 2

OH 2

R = H, C

Hn 2n+1

xFASE ethoxylatesCn

F2n+1

S(O)

N(R)CH 2

CH 2

O(CH 2

CH 2

O) 2

Hm

R = H, CH

, C 3

H 2

... 5

xFAS acrylates Cn

F2n+1

S(O)

N(R)CH 2

CH 2

OC(O)C(R’)=CH 2

2

R, R’ = H, CH

, C 3

H 2

... 5

side-chain fluorinated (meth)acrylate polymers

SaMPAPsCn

F2n+1

S(O)

N(R)CH 2

CH 2

OP(O)(OH) 2

(mono-) 2

[C

Fn2n+1

S(O)

N(R)CH 2

CH 2

O] 2

P(O)(OH) (di-) 2

[C

Fn2n+1

S(O)

N(R)CH 2

CH 2

O] 2

P(O) (tri-) 3

R = H, CH

, C 3

H 2

... 5

side-chain fluorinated urethane polymersOther PASF-based derivatives

xFASAs Cn F2n+1

S(O)

NHR 2

R = H, C

Hn 2n+1

PFCAsCn

F2n+1

C(O)OH

n:2 FT iodides (n:2 FTIs)Cn F2n+1

CH

CH 2

I 2

n:2 FT olefins (n:2 FTOs)Cn F2n+1

CH=CH

2

n:2 FT alcohols (n:2 FTOHs)Cn F2n+1

CH

CH 2

OH 2

n:2 FT phosphate esters (PAPs)Cn

F2n+1

CH

CH 2

OP(O)(OH) 2

(monoPAPs) 2

(C

Fn2n+1

CH

CH 2

O) 2

P(O)(OH) (diPAPs) 2

(C

Fn2n+1

CH

CH 2

O) 2

P(O) (triPAPs) 3

side-chain fluorinated urethane polymersn:2 FT stearate monoester (n:2 FTS)Cn

F2n+1

CH

CH 2

O(O)CC 2

H 17 35

n:2 FT (meth)acrylates (n:2 FT(M)ACs)Cn

F2n+1

CH

CH 2

OC(O)C(R)=CH 2

2

R = H, CH

, ... 3

side-chain fluorinated (meth)acrylate polymers, e.g.

n:2 FT ethoxylates (n:2 FTEOs)Cn

F2n+1

(CH

CH 2

O) 2

Hm

e.g. 27619-90-5, C

Fn 2n+1

CH

CH 2

S(O) 2

Cl 2

n:2 FT sulfonamide alkylbetaine (n:2 FTABs)Cn F2n+1

CH

CH 2

SO 2

NH(CH 2

) 23

+N (CH

) 32 CH

C(O)O 2

n:2 FT sulfonic acids (n:2 FTSAs)Cn

F2n+1

CH

CH 2

S(O) 2

OH 2

Cn F2n+1

CH

CH 2

SCN or 2

Cn F2n+1

CH

CH 2

SH 2

Cn

F2n+1

CH

CH 2

SiCl 2

3

Other n:2 FT derivatives,

e.g.,

Cn F2n+1

CH

CH 2

SR, R = CH 2

CH 2

COO 2

+Li , C H

CH 2

N 2 +R

X 3

, etc.

(reaction with RSH)

Cn

F2n+1

CH

CH 2

SCH 2

CH 2

R, 2

R = e.g., C(O)OCH

3

CH

CH^2

CH

CH^2 C

C

ClCl C

CH^2

O CH^3 CH^2 O

O CF^3 CF^2 CH^2 O

m 2

n a

b

c

B

side-chain fluorinated siloxanes and silicones

Fig. 2. Multistep multicomponent syntheses yield a complex PFAS universe.

Shown are

intermediate and final manufacturing products (

A ,B

). *PFCAs have also been synthesized using

other routes, e.g., from PFAIs or n:2 fluorotelomer iodides. Different synthesis routes may generatePFCAs with different perfluorocarbon chain lengths. **Additional details on known synthesisroutes of PASF-based and n:2 fluorotelomer derivatives can be found in (B). ***For manycompounds such as HFP and TFE, there are different synthesis routes with different startingmaterials, and only one of them is shown here. ****PFAIs may also be synthesized from otherinitial substances such as (CF

3)2

)CFI. [Sources: for

Fig. 2

(^8

), (

9 ), (

29

), (

30

), (

164

).]

RESEARCH | REVIEW

Science - USA (2022-02-04)

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