Synthesis and characterization of a new class of polyfluorinated alkanes: Tetrakis(perfluoroalkyl)alkane

Article abstract of DOI:10.1016/S0022-1139(02)00338-X

The synthesis and physico-chemical characterization of 1,1,2,2-tetrakis(perfluoroalkyl-methylene)ethane {[F(CF₂)_nCH₂]₂CH}₂ (n=6, TK6;n=8, TK8 ) are reported. The synthesis consists of four steps: (1) addition of allyl alcohol to a perfluoroalkyl iodide, F(CF₂)_nI(n=6,8) to give the corresponding iodo-adduct; (2) dehalogenation of the adduct by treatment with zinc in aqueous acetic acid, yielding 3-perfluoro-n-alkyl-1-propene; (3) addition of 3-perfluoro-n-alkyl-l-propene to perfluoroalkyl iodide, F(CF₂)_nI (n=6,8) to give 1,3-perfluoro-n-alkyl-2-iodo-propane; (4) coupling of 1,3-perfluoro-n-alkyl-2-iodo-propane by zinc in acetic anhydride giving the final products. TK6 and TK8 are characterized by very low surface tension values and exhibit very good properties as potential ski-waxes.

Full text of DOI:10.1016/S0022-1139(02)00338-X

Journal of Fluorine Chemistry 121 (2003) 57–63
Synthesis and characterization of a new class of polyfluorinated
alkanes: tetrakis(perfluoroalkyl)alkane
G. Gambarettoa, L. Contea, G. Fornasieria, C. Zarantonelloa, D. Toneia, A. Sassib, R. Bertania,b,*
a
`
Dipartimento Processi Chimici dell’Ingegneria, Facolta di Ingegneria, Via Marzolo 9, 35131 Padova, Italy
`
Istituto di Scienze e Tecnologie Molecolari, CNR, Facolta di Ingegneria, Via F. Marzolo 9, 35131 Padova, Italy
b
Received 5 August 2002; received in revised form 22 November 2002; accepted 28 November 2002
Abstract
The synthesis and physico-chemical characterization of 1,1,2,2-tetrakis(perfluoroalkyl-methylene)ethane {[F(CF2)nCH2]2CH}2 (n ¼ 6,
TK6; n ¼ 8, TK8) are reported. The synthesis consists of four steps: (1) addition of allyl alcohol to a perfluoroalkyl iodide, F(CF2)nI (n ¼ 6; 8)
to give the corresponding iodo-adduct; (2) dehalogenation of the adduct by treatment with zinc in aqueous acetic acid, yielding 3-perfluoro-n-
alkyl-1-propene; (3) addition of 3-perfluoro-n-alkyl-l-propene to perfluoroalkyl iodide, F(CF2)nI ðn ¼ 6; 8Þ to give 1,3-perfluoro-n-alkyl-2-
iodo-propane; (4) coupling of 1,3-perfluoro-n-alkyl-2-iodo-propane by zinc in acetic anhydride giving the final products. TK6 and TK8 are
characterized by very low surface tension values and exhibit very good properties as potential ski-waxes.
# 2002 Elsevier Science B.V. All rights reserved.
Keywords: (Perfluoroalkyl)alkanes; Perfluoroalkyliodides; Wurtz reaction; Fluorinated lubricants
1. Introduction
through a moulding process in order to improve water repel-
lence as ski-waxes, are generally prepared in two steps:
It is well known that perfluorinated materials are char-
acterized by extremely low surface tension values [1] which
makes them very useful in the field of lubrication, in
particular, in the formulation of lubricants for polyethylene
snow articles such as skis, snowboards and sleds [2–4]. The
phenomenon of kinetic loss during snow sliding is very
complex, but it can be separated into two components: dry
friction (caused by the friction of snow particles against the
running surface) and, more important, capillary suction
(adherence of water to the moving surface producing a
suction effect) [5,6]. This latter effect can be minimized
by using water-repellent materials like perfluorinated com-
pounds. Perfluoropolyethers, diblock semifluorinated-n-
alkanes and perfluoro-n-alkanes are among the best known
and most commonly used compounds in this class.
Although perfluoropolyethers [7] (Fomblin1, Kritox1) are
very good lubricants for extreme operating conditions, their
performance is not optimal because they contain an ethereal
bond that gives them only a moderate water-repellence.
Semifluorinated-n-alkanes, RF–RH, which are partially com-
patible with paraffins, where they are incorporated as additives
(1) Addition of a perfluoroalkyl iodide, F(CF2)nI, n ¼ 4, 6,
8, 10, 12, to a linear 1-alkene, CH2¼CH(CH2)mÀ2H,
m ¼ 10À24, to give the corresponding iodo-adduct
(Eq. (1)):
FðCF2ÞnI þ CH2¼CHðCH2ÞmÀ2H
! FðCF2ÞnÀCH2ÀCHIÀðCH2ÞmÀ2H
(1)
The reaction is induced by means of a radical initiator
(generally AIBN, 2,20-azobis(2-methylpropionitrile)
that abstracts the iodine atom from RFI forming an
RF radical that adds irreversibly to the alkene [7–21].
(2) The second step consists of the reductive dehalogena-
tion of the iodo-adduct (Eq. (2)):
FðCF2ÞnÀCH2ÀCHIÀðCH2ÞmÀ2H
ÀHI
!FðCF2ÞnÀCH¼CHÀðCH2ÞmÀ2H;
Zn;Hþ
FðCF2ÞnÀCH¼CHÀðCH2ÞmÀ2 ! FðCF2ÞnðCH2ÞmH
(2)
which can be accomplished by treatment with zinc
powder in acetic acid [22], or alternatively in either
gaseous [23,24] or aqueous [20,25] HCl in ethanol (or a
different suitable solvent) or employing lithium
* Corresponding author. Tel.: þ39-49-8275731; fax: þ39-49-8275525.
E-mail address: roberta.bertani@unipd.it (R. Bertani).
0022-1139/02/$ – see front matter # 2002 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0022-1139(02)00338-X

58
G. Gambaretto et al. / Journal of Fluorine Chemistry 121 (2003) 57–63
aluminium hydride in anhydrous diethyl ether [16,
17,20].
compounds exhibit improved performance in the field of
ski-waxes. The high molecular weights (MW(C30H10F52),
1358 and MW(C38H10F68), 1758) provide very low vapor
pressure and the water repellence, as determined by contact
angle measurement, even higher than that of perfluoro-
paraffins.
Perfluoro-n-alkanes, in principle telomers of polytetra-
fluoroethylene, are generally prepared by the coupling of
perfluoroalkyl iodide, F(CF2)nI, n ¼ 6, 8, 10, 12, using zinc
[14,26,27] (Eq. (3)):
FðCF2ÞnI þ FðCF2ÞmI þ Zn ! FðCF2ÞnþmF þ ZnI2
(3)
2. Results and discussion
Perfluoro-n-alkanes are characterized by very low surface
tension (15–17 mN mÀ1) and very high chemical inertness.
Their high repellence to water and dirt gives the resulting
perfluoro-paraffin ski-waxes excellent performance in terms
of sliding capability. However, the melting temperatures of
these compounds [MPðC12F26Þ ¼ 73:7 8C, MPðC16F34Þ ¼
126:8 8C] are rather high, which makes their application to
polyethylene ski soles difficult. Moreover they possess high
vapor pressures that cause sublimation of the product and
consequent loss from the surface onto which it is applied
[28,29]. Finally, perfluoro-n-alkanes are insoluble in the
polyethylene ski surfaces and are therefore only absorbed
physically on the porous ski soles inducing further loss of
material.
In the present paper, the synthesis and characterization of
a new class of fluorinated compounds 1,1,2,2-tetrakis-per-
fluoro-n-alkyl-alkanes, in particular of {[F(CF2)nCH2]2-
CH}2 with n ¼ 6 (TK6) and n ¼ 8 (TK8), are reported.
These compounds consist of a symmetrical arrangement of
four perfluorinated chains attached to a hydrogenated core.
This particular structure opposes crystallization and there-
fore the melting temperature is lower than that of a per-
fluoro-n-alkane of the same molecular weight. These
2.1. Syntheses of TK6 and TK8
The synthesis of 1,3-perfluoro-n-alkyl-1-propanes TK6
and TK8 was performed as reported in Scheme 1 via the
following four steps:
(1) addition of allyl alcohol to a perfluoroalkyl iodide,
F(CF2)nI ðn ¼ 6; 8Þ to give the corresponding iodo-
adducts 1a and 1b, respectively (Eq. (4));
(2) dehalogenation of the adduct by treatment with zinc in
aqueous acetic acid, yielding 3-perfluoro-n-alkyl-1-
propenes 2a and 2b, respectively (Eq. (5));
(3) addition of the 3-perfluoro-n-alkyl-l-propene to the
corresponding perfluoroalkyl iodide, F(CF2)nI
ðn ¼ 6; 8Þ giving the 1,3-perfluoro-n-alkyl-2-iodo-pro-
panes 3a and 3b, respectively (Eq. (6));
(4) coupling of the compounds 3 by zinc in acetic
anhydride yielding the final products TK6 and TK8
(Eq. (7)).
The synthesis can be accomplished starting from an
allylic compound (either chloride or alcohol). The first trials
were performed by using allyl choride [30]. Since the boiling
Scheme 1.

G. Gambaretto et al. / Journal of Fluorine Chemistry 121 (2003) 57–63
59
point of this compound (BPallyl chloride ¼ 45 8C) is lower than
2.2. Characterization of TK6 and TK8
the decomposition temperature of the initiator AIBN
(Tdec ¼ 75 8C), the synthesis must be performed in an auto-
clave. Under these reactions conditions (T ¼ 80 8C;
P ¼ 10 atm; reagent ratio RFI:allyl chloride ¼ 2:1) a mixture
of products is formed and the conversion of reagents is not
complete (90% conversion after 3 h). The reactions have
been followed by GLC and the chromatograms obtained
showed the formation of the F(CF2)nCH2CHICH2Cl
adducts, together with small quantities of the correspond-
ing olefins 2 and adducts 3. Separation of products 2 by
fractional distillation is difficult because their boiling
points are close to those of the corresponding perfluor-
oalkyl iodide compounds. Thus, the yield of the desired
products, F(CF2)nCH2CHICH2Cl ðn ¼ 6; 8Þ, is not higher
than 54% based on RFI used. The dehalogenation reaction
of F(CF2)nCH2CHICH2Cl proceeds smoothly with little
formation of by-products (yield ca. 90%). The yield of the
entire process is about 50% [31].
An alternative method to produce the olefins 2 proceeds
from addition of perfluoroalkyl iodides to allyl alcohol. This
process is easier because it is not necessary to perform the
alkylation reaction in an autoclave (BPalcohol ¼ 97:1 8C).
GLC analysis of the reaction mixture shows that in this
case the yield in 1 is very high (ca. 90%) with very low
formation of by products. A great improvement in the rate of
reaction was achieved by the synergic action of sodium
metabisulfite and AIBN [32]. It has been proposed that
bisulfite suppresses side reactions that slow the RFI addition
reaction. The azonitrile initiator gives rise to the radical
CH2CHCH(ꢀ)OH, to which a rapid transfer of an hydrogen
atom occurs [33,34]. The reaction goes to completion in
about 4 h whereas the reaction requires more than 20 h and a
considerable excess of alcohol if the bisulfite is not added.
The dehalogenation of adducts 1, F(CF2)nCH2CHI-
CH2OH ðn ¼ 6; 8Þ with zinc in acetic acid is not so efficient
(Eq. (5), Scheme 1); the reaction goes rapidly to completion,
but there is significant formation of by-products (predomi-
nantly F(CF2)nCH2CH2CH2OH) together with the olefins 2
in about 70% yield. Further addition of the perfluoroalkyl
iodide ðn ¼ 6; 8Þ on allyl substrates F(CF2)nCH2CH¼CH2
ðn ¼ 6; 8Þ is performed (Eq. (6), Scheme 1) to obtain the
iodine adducts 3, F(CF2)nCH2CHICH2(CF2)nF in the pre-
sence of AIBN.
The compounds TK6 and TK8 are low melting point
colorless solids, which have been characterized with spectro-
scopic techniques. As TK6 and TK8 are soluble exclusively in
perfluorinated compounds (such as perfluorodecalin or CFCs)
1H and 13C NMR spectra were recorded in perfluorinated
solvents. The particularly broad signals of the proton reso-
nances indicate a restricted molecular motion, probably due to
the fact that the protons are isolated from the solvent mole-
cules by the perfluoroalkyl groups wrapped in around the non-
fluorinated core. For this reason it was not possible to
obtain crystals suitable for X-ray determinations, even at
low temperature.
13C NMR spectra of solid products TK6 and TK8 are
reported in Fig. 1, with indication of the particular pulse
sequence employed. Two broad signals were detected for
each sample, attributable to carbons in the RF and RH
moieties, respectively. The signals occur practically at the
same chemical shift for TK6 and TK8 (CH, CH2 ¼ 25 ppm,
CF3 and CF2 ¼ 110 ppm).
The ability of the CP sequence to yield more intense
signals for carbons bonded to protons is emphasized in both
TK samples, while in the HPDEC spectra signals of RF and
RH carbons display a relative intensity that corresponds
more closely to the effective molecular formula.
Both sequences employed revealed the rigid character of
RF and RH moiety in TK6 and TK8 materials, as the signal to
noise ratio is low and bandwidth is very large.
DSC analyses of TK6 and TK8 show an intense melting
endotherm peak, which occurs at 97.16 and 82.58 8C, respec-
tively. It is noteworthy that the melting point of the heavier
TK8 compound is lower than that of TK6. These melting
temperatures are significantly lower than those of perfluori-
nated n-alkane compounds, semifluorinated n-alkanes or
n-alkanes with the same number of carbon atoms [23].
In Table 1, the values of contact angles and surface
tensions for TK6 and TK8 are reported, in comparison with
other perfluorinated compounds and some fluorinated poly-
mers. Surface free energy of the solid, gs, was calculated
using the contact angles with the Eqs. (8) and (9), which
were proposed by Owens and Wendt [36b] who extended the
Fowkes concept [36a]:
!
!
pffiffiffiffiffi
pffiffiffiffiffi
qffiffiffiffiffi
gld
gl
glp
gl
The final products TK6 and TK8 were obtained by
coupling of F(CF2)nCH2CHICH2(CF2)nF by treatment with
zinc in acetic anhydride (Wurtz-type reaction) [35]. The
suggested mechanism for the Wurtz reaction involves the
iodine–metal exchange to form an organometallic com-
pound which then reacts with a second molecule of halide
to form the final perfluoroalkane product in a high yield
(usually >95%). The dimerization reaction of 3 is less
efficient: there is almost complete conversion of the starting
compound, but the yield of the desired product is about 50%.
The mixture obtained contains two other compounds which
have not been identified.
pffiffiffiffiffi
1 þ cos y ¼ 2 gds
þ 2 gps
(8)
(9)
gs ¼ gds þ gps
where y is the contact angle, gl the surface free energy of the
liquid and gdl and gpl are its dispersion and polar components,
respectively; gs is the solid free energy and gds and gsp are its
components. The dispersion and the polar components of the
surface free energy of water are 21.8 and 51.0 mN mÀ1
,
respectively, and those of the di-iodomethane are 49.5 and
1.3 mN mÀ1, respectively [36b].

60
G. Gambaretto et al. / Journal of Fluorine Chemistry 121 (2003) 57–63
Fig. 1. 13C NMR spectra of solid products TK6 and TK8, with indication of the particular pulse sequence employed.
Table 1
Contact angles values and surface tension calculated according to Owens method [36] of TK6 and TK8
Compound
YH OðdegÞ
YCH I ðdegÞ
gtot (mN mÀ1
)
gdisp (mN mÀ1
)
gpol (mN mÀ1
)
2
2 2
TK6
TK8
138.3 ꢂ 1.0
137.4 ꢂ 1.3
122.3 ꢂ 2.1
119
128.9 ꢂ 1.3
127.5 ꢂ 1.5
103.0 ꢂ 1.3
107
(1.8)
(2.0)
7.7
(1.6)
(1.8)
7.3
(0.2)
(0.2)
0.4
C
16F34
C20F42
6.7
5.5
1.2
Poly(tetrafluoroethylene)
108
88
19.1
18.6
0.5
Y
: contact angle of water on the compound; Y
: contact angle of di-iodomethane on the compound; gtot (mN mÀ1): interfacial energy; gdisp
CH2I2ðdegÞ
H2OðdegÞ
(mN mÀ1): interfacial energy (dispersion component); gpol (mN mÀ1): interfacial energy (polar component).
It is noteworthy that the values of YH O and YCH I for
Allyl chloride, allyl alcohol and AIBN (2,20-azobis(2-
2
2 2
TK6 and TK8 are significantly higher than those of the other
fluorinated compounds, with lower energy tension values
(either molecular dispersion energies and polar interaction
term). In this context, the limitations of the model and
equation used must be taken into account [36].
methylpropionitrile) were purchased from Aldrich Chemical
Co. All other reagents employed were common laboratory
materials. All the chemical reagents were used as received.
All the reactions were performed under inert atmosphere
(N2).
In conclusion, the compounds TK6 and TK8, on the basis
of their high molecular weight, low vapor pressure, and at
the same time low melting point and low surface tension,
appear to be good candidates for ski-waxes, as indicated by
some preliminary results.
3.2. Analysis
GLC analyses of the reaction mixtures were performed
using a Shimadzu GC-8A instrument (2 m ꢁ 2 mm stainless
steel column packed with FS on 100–120 mesh Chromosorb
P) connected to a Shimadzu C-R3A integrator. Typical
operative conditions were: temperature programme 50 8C
for 6 min, 20 8C/min to 250 8C; He as gas carrier 24 ml/min.
GC/mass spectra were measured on a Carlo Erba Instru-
ment MFC 500/QMD1000 using a silica fused capillary
PS264 column ð30 m ꢁ 0:25 mmÞ and on a Finnigan Mat
TSQ7000 (capillary column 30 m ꢁ 0:32 mm). Typical
3. Experimental
3.1. Reagents and general procedure
Perfluorohexyl iodide and perfluorooctyl iodide were
commercial grade reagents supplied by Elf Atochem S.A.

G. Gambaretto et al. / Journal of Fluorine Chemistry 121 (2003) 57–63
61
conditions were: temperature programme 60 8C for 2 min,
10 8C/min to 280 8C; He as gas carrier 1 ml/min).
FTIR spectra were measured using a Nicolet Avatar
MS m/z (rel. ab. %): 503 ([M À H]þ, 1%); 487 ([M À
OH]þ, 3%); 377 ([M À I]þ, 80%); 357 ([M À I À HF]þ,
58%); 337 ([M À I À 2HF]þ, 8%); 69 ([CF3]þ, 100%). FTIR
spectrophotometer.
(nujol): nOH 3365 cmÀ1
, , nC–O
nCF 1122–1321 cmÀ1
1H and 13C {1H} NMR spectra were recorded on a Bruker
200 AC spectrometer operating at 200.13 and 50.32 MHz,
respectively. Peak positions are relative to Me4Si and were
calibrated against the residual solvent resonance (1H) or the
deuterated solvent multiplet (13C). 19F NMR measurements
were recorded on a Varian FT 80 spectrometer operating at
74.844 MHz. Peak positions are reported relative to CFCl3.
Solid-state NMR analyses were performed using a Bruker
AC200 spectrometer. Samples were spun at room tempera-
ture at 3000 kHz in 7 mm diameter zirconia rotors with Kel-
F caps. All spectra were obtained by using both the standard
Bruker cross-polarization pulse sequence (CP/MAS) and
single pulse experiments with high power decoupling
(HPDEC/MAS). In both cases, decoupling was applied
during acquisition. The 50.32 MHz solid-state 13C CP/
MAS NMR spectra were obtained with a 3 ms contact time
and a 10 s relaxing delay, recording the free induction decay
over a sweep width of 50 kHz, during an acquisition time of
0.08 s in a 8 K data set, and were processed with 40 Hz
exponential line broadening. 13C cross-polarization experi-
ments were optimized using adamantane. The Magic Angle
condition was adjusted observing 79Br spinning side bands
pattern in a rotor containing 5% KBr [37]. The 13C chemical
shifts were externally referenced to solid sodium 3-(tri-
methyl-silyl)-1-propane-sulfonate at 0 ppm.
1043 cmÀ1
.
1H NMR: (CD2Cl2) d 2.90 (m, CH2); 4.41
3
3
3
(tt, JHH 6.6, JHH 6.7, CHI); 3.79 (d, JHH 6.6, CH2O),
2.19 (s br, OH). (CD3COCD3) d 3.30 (m, CHCF2); d 2.77 (m,
CHCF2); 4.34 (m, CHI); 3.92 (m, CH2O), 3.01 (s br, OH).
19F NMR (CD2Cl2): d À81.2 (t, 3JFF 9.7, CF3); À113.7 (m,
CF2CH2); À122.1, À123.2, À123.9, À126.4 (m, CF2). 13
C
NMR (CD3COCD3): d 20.55 (s, CHI), 38.11 (t, 2JCF 20.73,
CH2CF2), 69.26 (s, CH2O), 108–130 (m, CF).
3.3.2. 3-Perfluoro-n-octyl-2-iodo-l-propanol,
F(CF2)8CH2CHICH2OH (1b)
The synthesis was performed according to the procedure
described for 1a starting from perfluoro-n-octyl-iodide
(742 g, 1.36 mol), Na2S2O5 (80.7 g in 253 g H2O), AIBN
(6.7 g, 0.04 mol) and allyl alcohol (118.2 g, 2.038 mol). The
final product obtained as a white solid was purified by
distillation (107–110 8C/10 Torr). Yield: 657 g, 74%.
MS m/z (rel. ab. %): 603 ([M À H]þ, 1%); 587 ([M À
OH]þ, 2%); 477 ([M À I]þ, 80%); 457 ([M À I À HF]þ,
40%); 437 ([M À I À 2HF]þ, 10%); 69 ([CF3]þ, 100%).
FTIR (nujol): nOH 3372 cmÀ1, nCF 1147–1241 cmÀ1, nC–O
1041 cmÀ1. H NMR (CD3COCD3) d 3.30 (m, CHCF2); d
1
2.82 (m, CHCF2); 4.34 (m, CHI); 3.83 (m, CH2O), 2.05 (s br,
OH). 19F NMR (CD2Cl2): d À80.74 (m, CF3); À113.1 (m,
CF2CH2); À122.4, À121.8, À123.2, À125.7 (m, CF2). 13
C
Differential scanning calorimetry (DSC) was measured
using a TA Instruments model DSC 2920 operating under
nitrogen flow. The measurements were carried out in the
range 30–350 8C and at a heating rate of 10 8C/min.
The surface free energy of TK6 and TK8 samples were
determined using a Kruss G10/DSA10 goniometer inter-
faced to image-capture software. Measurements were made
with de-ionized water and di-iodomethane taking an average
of 10 15 ml drops with each type of liquid.
NMR (CD3COCD3): d 20.51 (s, CHI), 38.07 (t, 2JCF 20.73,
CH2CF2), 69.22 (s, CH2O), 106–124 (m, CF).
3.3.3. 3-Perfluoro-n-hexyl-l-propene,
F(CF2)6CH2CH¼CH2 (2a)
In a four necked Pyrex glass round bottomed flask
equipped as for the preparation of 1a, F(CF2)6CH2CHI-
CH2OH (187.3 g, 0.37 mol) was mixed with a 30% aqueous
solution of acetic acid (221.4 g). The resulting mixture was
heated at 85 8C with stirring. Powdered zinc (35.4 g,
0.54 mol) was added in small portions over a 4 h period
and reaction mixture was stirred for a further 2 h. Aqueous
HCl (3 ml) was added and mixture was stirred for further
4 h at 80 8C to destroy excess zinc. The two resulting
phases were separated and the organic phase was distilled
(80–85 8C/680 Torr) obtaining 80.2 g (60%) of 2a.
MS m/z (rel. ab. %): 361 ([M þ H]þ, 2%); 360 (Mþ, 15%);
295([M À C2H3F2]þ, 16%); 169 ([C3F7]þ, 4%); 119
([C2F5]þ, 20%); 91 ([C4H5F2]þ, 100%); 69 ([CF3]þ,
50%); 41 ([C3H5]þ, 99%). FTIR (nujol): nCF 1122–
3.3. General procedure
3.3.1. 3-Perfluoro-n-hexyl-2-iodo-l-propanol,
F(CF2)6CH2CHICH2OH (1a)
Perfluoro-n-hexyl iodide (177 g, 0.40 mol) was heated
to 75 8C in a four necked 2 l Pyrex glass round bottomed
flask equipped with a mechanical stirrer, thermometer,
dropping funnel and a condenser. A 30% aqueous solution
of Na2S2O5 (35 ml) was then added [38]. The result-
ing mixture was heated at 80 8C and AIBN (0.80 g,
0.0048 mol) was added. The allyl alcohol (24 g, 0.41
mol) was then added dropwise and the solution was stirred
for 90 min at 80 8C. The white solid that formed was
decanted off, washed by stirring with water (400 ml at
80 8C), and, after cooling, was filtered off. The product was
finally purified by distillation (70–76 8C/2 Torr). Yield
187.3 g, 93%.
1348 cmÀ1, nC¼C 1649 cmÀ1. H NMR (CD2Cl2): d 2.87
1
(dtt, 3JHH 6.9, 3JHF 11.5, 4JHH 1.29, CH2); 5.81 (m, CH¼);
5.37 (m, CH¼); 5.31 (m, CH¼). 19F NMR (CD2Cl2): d
À81.2 (m, CF3); À113.5 (m, CF2CH2); À122.1, À123.2,
À126.4 (m, CF2). 13C NMR (CD3COCD3): d 36.94 (t, 2JCF
21.2, CH2CF2), 126.97 (CH¼), 123.88 (CH2¼), 110–124
(m, CF).

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G. Gambaretto et al. / Journal of Fluorine Chemistry 121 (2003) 57–63
3.3.4. 3-Perfluoro-n-octyl-l-propene,
previously treated with powdered zinc (3 g) to remove traces
of acetic acid. The resulting mixture was heated at 60–65 8C
for 4 h, during which time powdered zinc (27.5 g, 0.42 mol)
was added in small portions. The solid product was sepa-
rated from acetic anhydride by decantation. The excess zinc
remaining in the solid product was destroyed by heating the
solid to 80 8C and continuously adding a solution of 10%
aqueous HCl. This solution was then cooled and the desired
product was separated from the aqueous phase by decanta-
tion and was then purified by distillation at 170–175 8C/
1 Torr. Yield 205 g, 37%. Calcd. for C30H10F52: C 26.53, H
0.74; Found: C 26.37, H 0.70. FAB/MS (m-nitrobenzylal-
cohol) (m/z, rel. ab. %): 1511 ([M þ NBA]ꢃþ, 30%); 1471
F(CF2)8CH2CH¼CH2 (2b)
The synthesis was performed according to the procedure
described for 2a starting from F(CF2)8CH2CHICH2OH
(657 g, 1.09 mol), aqueous solution of acetic acid (200 g)
and zinc (71.2 g, 1.08 mol).The product was distilled (60–
63 8C/20 Torr).Yield 280 g, 56%.
MS m/z (rel. ab. %): 461 ([M þ H]þ, 1%); 460 ([M]þ,
10%); 395 ([M À C2H3F2]þ, 15%); 91 ([C4H5F2]þ, 95%); 69
([CF3]þ, 30%); 41 ([C3H5]þ, 100%). FTIR (nujol): nCF
1115–1348 cmÀ1, nC¼C 1650 cmÀ1. 1H NMR (CD3COCD3):
d 3.05 (dt, 3JHH 7.0, 3JHF 19.1, CH2); 5.84 (m, CH¼); 5.40 (m,
CH2¼). 19F NMR (CD3COCD3): d À80.99 (t, 3JFF 9, CF3);
À112.7, À113.9 (m, CF2CH2); À121.6, À122.4, À123.2,
À126.0 (m, CF2). 13C NMR (CD3COCD3): d 37.05 (t,
2JCF 22.3, CH2CF2), 126.97 (CH¼), 123.75 (CH2¼), 113–
121 (m, CF).
([1511-2HF]ꢃþ, 40%). FTIR: nCF 1122–1246 cmÀ1, br. H
1
NMR (CD3COCD3, perfluorodecaline): d 0.93 (m, CH2); d
1.85 (m, CH). 13C NMR (CD3COCD3, freon 113): d 28.24
2
(s, CH), d 31.40 (t, JCF 21.6, CH2CF2), 106–124 (m, CF).
3.3.5. 1,3-Perfluoro-n-hexyl-2-iodo-propane,
F(CF2)6CH2CHICH2(CF2)6F (3a)
3.3.8. 1,1,2,2-Tetrakis(perfluorooctyl-methylene)ethane
{[F(CF2)8CH2]2CH}2 (TK8)
F(CF2)6CH2CH¼CH2 (201 g, 0.56 mol) was mixed with
F(CF2)6I (256 g, 0.58 mol) in a 1 l four necked flask equipped
with a condenser, mechanical stirrer and a thermometer. The
mixture was heated under nitrogen to 85 8C and AIBN
was added (5.1 g, 0.03 mol), then the solution was heated
at 85 8C for 20 h, with the further addition of AIBN during
the reaction time (ca. 1 g every 4 h). The product was purified
by distillation (100–107 8C/1 Torr). Yield 440 g (97%).
MS m/z (rel. ab. %): 679 ([M À I]þ, 4%); 659 ([M À I À
HF]þ, 12%); 345 ([C8H2F13]þ, 17%); 295 ([C7H2F11]þ, 36%);
169 ([C3F7]þ, 10%); 119 ([C2F5]þ, 27%); 69 ([CF3]þ, 80%).
FTIR (nujol): nCF 1236,br. 1H NMR (CD2Cl2): d 4.53 (q, 3JHH
6.6, CH); 2.97 (m, CH2). 19F NMR (CD2Cl2): d À81.2 (tt, 3JFF
TK8 was prepared according to the procedure described
for TK6, starting from F(CF2)8CH2CHICH2(CF2)8F (490 g,
0.49 mol), zinc (32 g,0.49 mol) and acetic anhydride
(500 ml). The product was separated from the aqueous phase
by decantation and purified by distillation at 213–217 8C/
1 Torr. Yield 214 g (25%). FAB/MS (m-nitrobenzylalcohol)
(m/z, rel. ab. %): 1758 ([M]ꢃþ, 30%). Calcd. for C38H10F68:
C 25.96, H 0.57; Found: C 26.61, H 0.52. FTIR: nCF 1100–
1250 cmÀ1, br. 1H NMR (CD3COCD3, perfluorodecaline): d
0.95 (m, CH2); d 1.66 (m, CH). 13C NMR (CD3COCD3,
CFC 113): d 29.33 (s, CH), d 31.27 (t, 2JCF 20.9, CH2CF2),
100–130 (m, CF).
4
9.7, JFF 2.2, CF3); À113.6 (m, CF2CH2); À121.9, À123.1,
À123.7, À126.3 (m, CF2). 13C NMR (CD3COCD3): d 0.93
References
2
(CHI), 42.38 (t, JCF 20.3, CH2CF2), 104–126 (m, CF).
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3.3.6. 1,3-Perfluoro-n-octyl-2-iodo-propane,
F(CF2)8CH2CHICH2(CF2)8F (3b)
(b) D. Myers, Surfactant Science and Technology, VCH, Weinheim,
1988.
This compound was prepared according to the procedure
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(10 g, 0.06 mol). 3b was distilled at 128–134 8C/7 Torr.
Yield 490 g (80%).
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MS m/z (rel. ab. %): 779 ([M À I]þ, 5%); 759 ([M À I À
HF]þ, 10%); 119 ([C2F5]þ, 30%); 69 ([CF3]þ, 80%). FTIR
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5.6, CH); 3.24 (m, CH2). 19F NMR (CD2Cl2): d À81.0 (t,
3JFF 10.0, CF3); À113.6 (m, CF2CH2); À121.5, À122.5,
À123.6, À126.0 (m, CF2). 13C NMR (CD3COCD3): d 0.94
~
2
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3.3.7. 1,1,2,2-Tetrakis(perfluorohexyl-methylene)ethane
{[F(CF2)6CH2]2CH}2 (TK6)
F(CF2)6CH2CHICH2(CF2)6F (320 g, 0.40 mol) was
mixed with acetic anhydride (580 ml) which had been

G. Gambaretto et al. / Journal of Fluorine Chemistry 121 (2003) 57–63
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