α-Branched-perfluorodiacyl peroxides: Preparation and characterization

Article abstract of DOI:10.1016/j.jfluchem.2005.01.003

New perfluorodiacyl peroxides substituted at the α position have been synthesized and characterized. This class of peroxides shows good hydrolytic stability.

Full text of DOI:10.1016/j.jfluchem.2005.01.003

Journal of Fluorine Chemistry 126 (2005) 587–593
www.elsevier.com/locate/fluor
a-Branched-perfluorodiacyl peroxides: preparation and characterization
Marco Galimberti a, Emma Barchiesi a, Walter Navarrini a,b,
*
a Solvay Solexis, R&D Centre, Viale le Lombardia, I-20021 Bollate (MI), Italy
b Dipartimento di Chimica, Politecnico di Milano, 7, via Mancinelli, I-20021, Milano, Italy
Received 28 September 2004; received in revised form 2 December 2004; accepted 13 January 2005
Available online 16 February 2005
This paper is dedicated to Prof. R.D. Chambers on his 70th birthday.
Abstract
New perfluorodiacyl peroxides substituted at the a position have been synthesized and characterized. This class of peroxides shows good
hydrolytic stability.
# 2005 Elsevier B.V. All rights reserved.
Keywords: Perfluorodiacyl peroxides; Preparation; Characterization; Hydrolysis; Thermolysis
1. Introduction
radicals are directly introduced at the extremity of the
polymer chain, allowing the preparation of fluoropolymers
with excellent thermal and optical properties [7], as well as
pharmaceutical properties [8]. The industrial research in this
area has been very active since the early discoveries [9–11].
However, there are a few drawbacks in the preparation,
purification and utilization of these peroxides. Perfluoroacyl
halides, chlorides, fluorides and perfluoro anhydrides are
generally utilized as starting materials for the preparation of
acyl peroxides with H2O2 in alkaline conditions. The low to
medium yields in their preparation are due to diacyl peroxide
and starting material hydrolysis. In fact the two strong
electron withdrawing perfluoro alkyl groups enhance the
rate of hydrolysis as compared to the hydrogenated diacyl
peroxide [1]. Wlassics found that the rate of hydrolysis
increases with increasing MW of the perfluorooxyalkyl
radical bonded to the carbonyl of the diacyl peroxide [12].
According to Diffendall et al. the higher the molecular
weight of the peroxide used in a dispersion, the longer the
peroxide survives before significant hydrolysis takes place,
although no specific data were reported [13].
Perfluoro diacyl peroxides are an interesting and useful
source of perfluoroalkyl radicals [1].
Their utility as initiators in the free radical polymeriza-
tion of fluoromonomers has been recognized since the early
1950s [2]. Recently, perfluoroalkyl free radical chemistry
has raised considerable interest, as demonstrated by many
important articles and reviews which appeared in the
specialized literature [1–6].
Along with the increasing importance of perfluoroalkyl
radical chemistry the number of initiation methods has also
increased, but the thermal decomposition of perfluorodiacyl
peroxides remains the method of choice for free radical
polymerization.
This is due to the mild thermal conditions required and
the clean reaction which generates perfluoroalkyl radical. In
addition, thermal homolytic peroxide decomposition is
monomolecular and auto-induced decomposition is not
observed in the range of peroxide concentrations used in the
polymerization initiation [6]. This initiation system cannot
act as a free radical transfer reagent and allows a better
control of the polymer molecular weight. Perfluoroalkyl
The presence of electron withdrawing groups, like
fluorine or perfluoroalkyl radicals bonded to the carbonyl
of the diacyl peroxide, also enhance their thermal homolytic
decomposition rates compared to hydrogenated diacyl
peroxides [1].
* Corresponding author. Tel.: +39 02 3835 6400; fax: +39 02 3835 6355.
E-mail address: walter.navarrini@solvay.com (W. Navarrini).
0022-1139/$ – see front matter # 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2005.01.003

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M. Galimberti et al. / Journal of Fluorine Chemistry 126 (2005) 587–593
Scheme 1.
Table 1
Thermolysis and hydrolysis data for peroxides 1–6 in CF2ClCFCl2 as solvent
Peroxide
T (C8)
Thermolysis,
kd (Â105 sÀ1
17.3
Hydrolysis,
kd (Â105 sÀ1
21.1
)
)
(1) Perfluoroisobutyrylperoxide, (CF3)2CFC(O)OOC(O)CF(CF3)2
(2) Perfluoro-2-methoxy-propionylperoxide, CF3(CF3O)CFC(O)OOC(O)CF(OCF3)CF3
(3) Perfluoro-2,2-dimethoxy-propionylperoxide, (CF3O)2CF3CC(O)OOC(O)CCF3(OCF3)2
70
20
15
30
1.8
1.5
7.6
7.3
11.7
13.9
(4) bis(perfluoro-5-methoxy-2,3-dioxolane-5-carbonyl)peroxide,
(5) bis(perfluorocyclobutane carbonyl)peroxide,
70
10.8
13.3
(6) Perfluorobutyrylperoxide, CF3CF2CF2C(O)OOC(O)CF2CF2CF3
(7) Fomblin Z-diacylperoxides (Mw = 529) [12], [CF3O(CF2O)r(CF2CF2O)sC(O)O]2
15
20
1.5
4.5
0.25
467
This behavior may give limitations in the choice of
polymerization conditions, particularly in the case of slow
reacting monomers for which high polymerization tem-
peratures are preferred [9]. Low polymerization tempera-
tures are instead chosen in the case of vinylidene fluoride
(CF2=CH2) polymer, where the formation of –CF2CH2–
Scheme 2.
CH2CF2– segments in the polymer backbone needs to be
controlled [10,14].
preparation, where highly hydrolytic conditions like aqueous
NaOH are utilized.
In order to overcome these limitations, we directed our
study towards the preparation of perfluoro diacyl peroxides
characterized by a good hydrolytic stability and by a wide
range of thermal decomposition temperatures.
The low molecular weight of the starting acylfluoride also
avoids the presence of annoying emulsions that are often the
cause of a low preparation yield [12].
The hydrolytic decomposition of perfluoro diacyl
peroxide substituted in the a position with respect to diacyl
peroxide is very low in de-ionized water, see Table 1.
Schemes 2 and 3 illustrate the thermal and the hydrolytic
decompositions, respectively, of this family of perfluoro
diacyl peroxides. As can be seen in Table 1, the hydrolysis
reaction of these peroxides does not substantially interfere
with the homolytic thermal decomposition in de-ionized
water. The hydrolysis is a heterogeneous reaction; therefore
its rate is also a function of the stirring efficiency and of the
presence of surfactants or cosolvents. The hydrolysis data
shown in Table 1 are important as relative values, in
particular in the case of linear di(perfluorobutyryl) peroxide
6 and perfluoro PFPE dialkanoyl peroxide 7, whose
‘‘hydrolytic kd’’ are three times and three orders of
magnitude higher than the ‘‘thermolytic kd’’, respectively.
On the contrary, thermolytic kd and hydrolytic kd for the
2. Results and discussion
Starting from low molecular weight perfluoroacyl
fluorides substituted in the a position, we obtained good
to medium yields in the preparation of a substituted
dialkanoyl peroxides utilizing the described preparation
method which employs hydrogen peroxide in aqueous
NaOH in a biphasic system [1,9], as illustrated in
Scheme 1.
The hydrolysis of the perfluoro diacyl peroxide end
product has been minimized choosing the proper experi-
mental conditions as shown in Section 4 and Table 4.
The presence of a bulky substituent a to the acylfluoride
decreases the hydrolysis side reactions in the diacyl peroxide
Scheme 3.

M. Galimberti et al. / Journal of Fluorine Chemistry 126 (2005) 587–593
589
Table 2
Thermolysis, Arrhenius and Eyring data for peroxides 1–5 in CF2ClCFCl2 as solvent
Peroxide
T (8C)
Thermolysis,
kd (Â105 sÀ1
Arrhenius
Eyring
)
ln(A)
Ea
(kJ molÀ1
DH#
(kJ molÀ1
DS#
(kJ molÀ1
)
)
)
(1) Perfluoroisobutyrylperoxide, (CF3)2CFC(O)OOC(O)CF(CF3)2
60
70
80
4.4
17.3
56.5
35.0
37.7
37.3
124.7
118.4
112.1
121.7
115.9
109.6
36.4
59.8
57.7
(2) Perfluoro-2-methoxy-propionylperoxide,
CF3(CF3O)CFC(O)OOC(O)CF(OCF3)CF3
20
30
40
1.8
9.9
40.8
(3) Perfluoro-2,2-dimethoxy-propionylperoxide,
(CF3O)2CF3CC(O)OOC(O)CCF3(OCF3)2
5
1.8
7.6
10
15
46.2
(4) bis(perfluoro-5-methoxy-2,3-dioxolane-5-carbonyl)peroxide,
20
30
40
3.1
33.2
106.3
103.8
22.6
11.7
50.2
(5) bis(perfluorocyclobutane carbonyl)peroxide,
60
70
80
3.0
34.5
124.7
121.7
33.0
10.9
38.5
a-branched peroxides 1–5, although not identical, have the
related values in the same range. It should be pointed out that
the hydrolysis kinetic constants kd of Table 1 are inclusive of
the inherent homolytic decomposition, therefore these data
should be considered as a computation of the homolytic and
hydrolytic decomposition (see Section 4.4).
The thermal decomposition of peroxides 1–5 (Scheme 2)
follows first-order kinetics (see Section 4.3). The decom-
position rate constants kd in CF2ClCFCl2 for peroxides 1–5,
calculated for three different temperatures, are reported in
Table 2. The activation energy and the kinetic parameters
calculated according to the Arrhenius and Eyring transition
Table 3
Thermolysis, Arrhenius and Eyring data for peroxides 8–10
Peroxide
T (8C)
Thermolysis,
kd (Â105 sÀ1
Arrhenius
Eyring
)
ln(A)
Ea
(kJ molÀ1
DH#
(kJ molÀ1
DS#
)
)
(kJ molÀ1
)
(8) Perfluoroacetylperoxide [17], CF3C(O)OOC(O)CF3
45
55
60
1.6
6.0
30.9
110.9
108.4
2.9
10.4
(9) Perfluoroproprionylperoxide [1], CF3CF2C(O)OOC(O)CF2CF3
(10) bis(perfluorocyclohexane carbonyl)peroxide [18],
25
1.2
118.8
35
40
45
0.7
1.7
3.1
30.6
108.4
105.8
1.6

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M. Galimberti et al. / Journal of Fluorine Chemistry 126 (2005) 587–593
state equations are also reported in Table 2, whereas data
derived from the literature of known peroxides are reported
in Table 3 for comparison.
From Tables 2 and 3, it can be seen that the activation
enthalpies for the decomposition of peroxides 1–5 are
generally higher than enthalpies of peroxides 8–10, with the
exception of peroxide 4. Activation entropies are also
higher; particularly for peroxides 2 and 3, probably
indicating a disordered transition state. The enthalpic
contribute for peroxides 1 and 5 prevails leading to high
value of DG# and consequent high temperature of
decomposition. The entropic contribute for peroxide 3
prevails, leading to low DG# value and consequent low
temperature of decomposition and also the fact that the
activated complex is more favorable than the reactants.
The thermal di(perfluoroalkanoyl) peroxide decomposi-
tion can be seen as a concerted process involving the
simultaneous homolysis of the C2–C1 and O–O bonds,
where the stability of the end perfluoroalkyl radical is an
important variable to determine the decomposition rate of
Scheme 4.
the starting diacyl peroxide [1,3,15–17]. The same reaction
has also been recognized as one-bond homolytic decom-
position process, depending on the nature and viscosity of
the solvent [21].
Although the data reported in Table 2 are not extrapolated
to zero viscosity as suggested by DeSimone et al. [21], the
nature of the substituents bonded to the carbonyl of the
diacyl peroxide is an important variable in determining the
homolytic decomposition rate of diacyl peroxide com-
pounds.
In Table 2 an increase in the decomposition rate from
dialkanoyl peroxide 1 to peroxide 2 can be seen. The thermal
decomposition reaction variation can be ascribed to a
different substitution at the a carbon of the dialkanoyl
Scheme 5.
Scheme 6.
Scheme 7.
Scheme 8.

M. Galimberti et al. / Journal of Fluorine Chemistry 126 (2005) 587–593
591
peroxide, trifluoromethyl radical and trifluoromethoxy
radical for peroxides 1 and 2, respectively, as shown in
Schemes 4 and 5.
4. Experimental
4.1. General methods, materials and safety precautions
A further increase in the decomposition rate is observed
from peroxide 2 to peroxide 3; this may be due to the second
trifluoromethyl group introduction at the a carbon of the
dialkanoyl peroxide, as shown in Scheme 6.
4.1.1. General methods
Volatile compounds were handled in a glass and/or
stainless-steel vacuum system equipped with glass/PTFE or
stainless-steel valves. Pressures were measured with a Druck
PDCR 110/W differential pressure gauge. Quantities of
gaseous reactants and products were measured from fixed
volumes assuming ideal gas behavior. 19F NMR spectra
were recorded on a Varian 200 MHz spectrometer; chemical
shifts are expressed as d values with neat CFCl3 as an
internal reference. IR spectra were obtained on a Perkin-
Elmer FTIR 1600. Mass spectra were performed on a Varian
Mat CH-A spectrometer in the electron impact mode at
ionization energy of 70 eV.
The di(perfluoroalkanoyl) peroxides 4 and 5 undergo the
formation of radicals centered on a secondary carbon atom
on cyclic structures (Schemes 7 and 8). The effect of the
destabilization of the peroxide due to the presence of two
oxygen atoms a to the perfluorinated dialkanoyl peroxide
observed for dialkanoyl peroxide 3 is not observed for
peroxide 4, this might be due to the strain of the five member
ring of the perfluorodiooxolyl radical shown in Scheme 7.
In Scheme 8 the perfluorocyclobutyl radicals derive from
the thermal decomposition of peroxide 5. The strain of the
four-member ring of perfluorocyclobutyl radical may be one
the reasons of the moderate increase of the stabilization of
this peroxide compared to peroxide 10 of Table 3.
The thermal behavior of peroxides 1–5 may be
interpreted through the stabilization/destabilization effect
of the substituents on the perfluoro radical formed by the
decomposition of the di(perfluoroalkanoyl) peroxide.
EPR spectroscopic studies will give experimental
information on the geometry and in particular on the degree
of ‘‘bending’’ of the radicals derived from the decomposi-
tion of peroxides 1–5. Concerning the geometry of
perfluoroalkyl radical by EPR study, Corvaia and coworkers
discovered a substantially planar perfluoroalkyl radical
intermediate in the addition of hypofluorite to highly
substituted perfluoro olefins [22], on the contrary Faucitano
et al. noticed a pyramidal structure for radical substituted by
a less bulky group in the photodecomposition of perfluoro
oxyalkylperoxides [23].
4.1.2. Materials
Chemicals were obtained from commercial sources and
directly utilized. Perfluoroacyl fluorides were prepared
according to standard methods described in the literature
[19,24].
4.1.3. Safety precautions
Perfluoroacyl fluorides react with moisture developing
HF and perfluoro carboxylic acids, some toxicity informa-
tion on these categories are available in Houben-Weyl [20].
Perfluorodiacyl peroxides may decompose very quickly
through auto induced decomposition [6]; solutions having
peroxides concentration as high as 15% have been prepared
and stored at appropriate temperature for days. Pure
peroxide samples were not prepared for safety reasons.
4.2. General peroxide preparation procedure
In a typical run, a 100 ml four-necked flask was equipped
with a mechanical stirrer, a solid CO2 condenser, a
thermometer and a dropping funnel; the alkaline conditions
were created dissolving NaOH in bi-distilled water, 40–
50 ml of solvent (CF2ClCFCl2) were added, the temperature
of the system was lowered by an external cooling bath to
about 0 8C, then the hydrogen peroxide was slowly
introduced. Finally, the acyl-fluoride was added drop by
drop in about 1 min employing a dropping funnel. The
exothermicity of the reaction was controlled by the cooling
bath, maintaining the internal temperature at about 2 8C;
3. Conclusions
In order to overcome the limitations of known perfluoro
diacyl peroxides, we have identified a class of perfluor-
odiacyl peroxide characterized by a good hydrolytic stability
and by a wide range of thermo decomposition temperatures
ranging from 0 up to 90 8C with a half time of few hours.
A class of peroxides so designed can be easily utilized as
initiators in a variety of polymerization or oligomerization
reactions [9].
Table 4
Experimental conditions, yields and purity for the preparation of peroxides 1–5
Peroxide
Acyl-F (mmol)
Na(OH) (mmol)
H2O2 (mmol)
Temperature (8C)
Reaction time (min)
Yield (%)
Purity (%)
1
2
3
4
5
47
44
26
23
30
49
49
35
25
33
94
90
62
43
60
2
0
0
2
0
10
12
90
10
25
70
69
46
56
55
99
95
95
99
96

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M. Galimberti et al. / Journal of Fluorine Chemistry 126 (2005) 587–593
Table 5
Table 6
Perfluorinated impurities present in the peroxides 1–5 solutions
Observed kinetic constant values (kobs) obtained at different initial peroxide
concentrations
Peroxide
Impurities
Initial peroxide 1 concentration (M)
kobs (Â105 sÀ1) (at 64 8C)
1
2
3
4
CF3OCF2CF2CF3, CF3OCF(CF3)2
CF3OCF2CF2OCF3, (CF3O)2CFCF3
(CF3O)2CFCF2OCF3
0.367
0.209
0.117
0.066
0.036
5.38
5.52
5.63
5.63
5.47
5
the handling of the peroxide. However, in the case of
peroxide 1 it has been experimentally verified that a high
initial concentration does not invalidate the results. In
Table 6 the kobs values obtained at different initial peroxide
concentrations are reported. Even increasing the initial
concentration ten times, it is possible to notice that the
kobs shows a maximum variation of 3% compared to the
mean value.
when the IR analysis confirmed the disappearance of the
typical band of the –C(O)F group of the acyl-fluoride, the
flask content was transferred into a separatory funnel and the
organic phase was washed with distilled water until a neutral
pH was obtained, then it was anhydrified with anhydrous
Na2SO4. The peroxide concentration was determined by
iodometric titration.
The yields in peroxide with respect to the different acyl-
fluorides, the amounts of the reagents, operative conditions
and purity are reported in Table 4.
The purity of peroxides 1–5 was verified through 19F
NMR, 1H NMR, GC–MS spectra. The purity values reported
in Table 4 were estimated from the 19F NMR spectra as the
integral of fluorine signals of the peroxide divided by the
integral of all fluorine signals present, excluding the solvent
and multiplied by 100.
The 1H NMR spectra showed no significant signals for all
peroxides prepared. The GC–MS, excluding the signal of the
solvent, gave signals of the product associated to the
coupling of the radicals formed in the decomposition of the
peroxides and signals associated to radical hydrogen
abstraction. GC–MS spectra of previously decomposed
peroxide samples gave signals associated to the coupling of
the radicals formed in the decomposition of peroxides; no
significant signals associated with radical hydrogen abstrac-
tion were present.
4.3.2. Decomposition kinetics methodology
In a typical kinetic measurement, about 1.5 ml of
peroxide solution were put in a glass test tube with screw
neck; a whole set of these tubes was placed in a thermostat
(Æ0.1 8C), and they were taken out at specified times and
immediately frozen to dry ice temperature. The tubes were
opened while cool, and 1.0 ml of the peroxide solution was
titrated by standard iodometry.
First-order rate constant at different temperatures
(Table 2) and activation parameters (Table 3) were
calculated by linear regression analysis.
4.4. Decomposition kinetics methodology in the
presence of water
In a typical kinetic measurement, about 1.5 ml of
peroxide solution and 2.0 ml of distilled water were put
in a small glass bottle with screw neck and a magnetic stir
bar; a whole set of these bottles was placed in a thermostated
bath under vigorous stirring, and they were taken out at
specified times and immediately frozen to ice temperature.
The bottles were opened while cool, and 1.0 ml of peroxide
solution was titrated by standard iodometry.
The perfluorinated impurities present in the peroxides
1–5 solutions were recognized as contamination already
present in the perfluoroacyl fluorides starting materials. GC
and NMR analysis allowed their identification; the nature of
the impurities was strictly due to the peculiar preparation of
the perfluoroacyl fluorides [24]. Table 5 shows the impurity
present in the peroxides 1–5 solutions.
First-order rate constant at different temperatures
(Table 1) were calculated by linear regression analysis.
4.5. Characterization of peroxide 1 [(CF3 )2CFaCOO]2
b
4.3. Kinetic measurements in the absence of water
19F NMR (188 MHz, CFCl3), d (ppm): À184.7 (m, 2F, Fa,
J = 8 Hz), À74.8 (d, 12F, Fb, J = 8Hz).
4.3.1. Decomposition kinetics at different peroxide
concentrations
IR spectrum main bands (cmÀ1, w: weak, m: mean, s:
strong, vs: very strong): 1853 (m), 1824 (m), 1309 (m) and
1264.
Literature information suggests to work at low peroxide
concentration (<0.05 M) for kinetics decomposition
experiments to avoid possible peroxide auto-induced
decomposition phenomena [6]. We utilized higher peroxide
initial concentrations (0.2–0.4 M) in order to reduce
the error in determining the turning point and improving
Mass spectrum gave signals associated to the coupling of
the radicals formed in the decomposition of the peroxides as
follows: main peaks and respective intensities: 319 (3), 281
(3), 231 (5), 181 (5), 131 (5), 69 (100).

M. Galimberti et al. / Journal of Fluorine Chemistry 126 (2005) 587–593
593
4.6. Characterization of peroxide 2
a
J = 230 N2) À131, 2 (d, 2F, Fd, J = 230 N2) and À188 (2F,
Fe).
[(CF3 O)(CFb )CFcCOO]2
3
IR spectrum main bands (cmÀ1, w: weak, m: mean, s:
strong, vs: very strong): 1843 (m), 1817 (m), 1289 (s) and
1232 (s).
Mixture of MESO and D,L form in 1/1 ratio. 19F NMR
(188 MHz, CFCl3), d (ppm): À53.0(m, 6F, Fa, MESO), À53.5
(m, 6F, Fa, D,L), À77.6 (m, 6F, Fb, D,L) À78.8 (m, 6F, Fb,
MESO), À141.8 (m, 2F, Fc, D,L), À144.0 (m, 2F, Fc, MESO).
IR spectrum main bands (cmÀ1, w: weak, m: mean, s:
strong, vs: very strong): 1857 (m), 1828 (s), 1284 (s) and 1232
(vs).
Mass spectrum gave signals associated to the coupling of
the perfluoroalkyl radicals formed in the decomposition
of the peroxides as follows: main peaks and respective
intensities: 293 (25), 262 (12), 243 (20), 193 (29), 162 (47),
100 (100) and 69 (37).
Mass spectrum gave signals associated to the coupling
of the perfluoroalkyl radicals formed in the decomposition
of the peroxides as follows: main peaks and respective
intensities: 281 (4), 263 (13), 219 (18), 185 (26), 131 (25), 97
(45) and 69 (100).
References
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4.7. Characterization of peroxide 3
a
[(CF3 O)2(CF3 )CCOO]2
b
19F NMR (188 MHz, CFCl3), d (ppm): À55.2 (s, 12F, Fa)
and À78.4 (s, 6F, Fb).
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IR spectrum main bands (cmÀ1, w: weak, m: mean, s:
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1254 (s).
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Mass spectrum gave signals associated to the coupling of
the perfluoroalkyl radicals formed in the decomposition of
the peroxides as follows: main peaks and respective
intensities: 263 (6), 251 (3), 135 (2), 97 (4), 69 (100).
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4.8. Characterization of peroxide 4 [cyclo-O–CFcFd–
OCFaFb–C(OCFe3)(COO)–]2
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J = 70, 9 Hz), À52.3 (s, 6F, Fe), À56.4 (dd, 2F, Fd, J = 70,
7 Hz), À75.2 (dd, 2F, Fa, J = 135, 9 Hz) and À89.5 (dd, 2F,
Fb, J = 135, 7 Hz).
IR spectrum main bands (cmÀ1, w: weak, m: mean, s:
strong,vs:verystrong):1857(m),1828(m),1349(m)and1236
(s).
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Mass spectrum gave signals associated to the coupling
of the perfluoroalkyl radicals formed in the decomposition
of the peroxides as follows: main peaks and respective
intensities: 229 (42), 163 (21), 135 (7), 116 (3), 97 (30), 78
(4), 69 (100) and 50 (6).
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4.9. Characterization of peroxide 5 [cyclo-CFaFb–CFcFd–
CFaFb–CFe(COO)–]2
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19F NMR (188 MHz, CFCl3), d (ppm): À126 (d, 4F, Fa,
J = 230 N2), À130 (d, 4F, Fb, J = 230 N3), À130, 4(d, 2F, Fc,