New catalytic alkylation of in situ generated perfluoro-alkyloxy-anions and perfluoro-carbanions

Article abstract of DOI:10.1016/j.jfluchem.2005.09.005

Alkyl fluoroformates R_HOC(O)F are a new family of excellent alkylating agents. Perfluoroacyl fluorides, selected perfluoroketones and fluoroolefins can be alkylated to hydrofluoroethers R_F-O-R _H and hydrofluoroalkanes R_F-R_H, respectively. Potassium fluoride and cesium fluorides catalysts in glymes at 50-100°C are the preferred experimental conditions.

Full text of DOI:10.1016/j.jfluchem.2005.09.005

Journal of Fluorine Chemistry 126 (2005) 1578–1586
www.elsevier.com/locate/fluor
New catalytic alkylation of in situ generated perfluoro-alkyloxy-anions
and perfluoro-carbanions
Marco Galimberti a, Giovanni Fontana a, Giuseppe Resnati b,
Walter Navarrini b,
*
a Solvay-Solexis, R&D Centre, 20, viale Lombardia, I-20021 Bollate (MI), Italy
b Dipartimento di Chimica, Politecnico di Milano,
7, via Mancinelli, I-20131 Milano, Italy
Received 17 June 2005; received in revised form 13 September 2005; accepted 17 September 2005
Available online 2 November 2005
Abstract
Alkyl fluoroformates RHOC(O)F are a new family of excellent alkylating agents. Perfluoroacyl fluorides, selected perfluoroketones and
fluoroolefins can be alkylated to hydrofluoroethers RF–O–RH and hydrofluoroalkanes RF–RH, respectively. Potassium fluoride and cesium fluorides
catalysts in glymes at 50–100 8C are the preferred experimental conditions.
# 2005 Elsevier B.V. All rights reserved.
Keywords: Fluoroformates; Alkylating agents; Hydrofluoroethers; Fluoride catalysts; Glymes
1. Introduction
anhydrous metal fluoride and an alkylating reagent like
dimethyl sulfate [7], alkyl triflate [8], exotic fluoro vinylalk-
ylethers [9] and dimethyl sulfite [10]. All these alkylating
methodologies have the disadvantage that they use a
stoichiometric amount of metal fluoride or employ an
alkylating reagent particularly difficult to prepare, like
fluorovinyl alkyl ethers. This alkylation reaction can also be
performed employing SbF5 as acid catalyst in anhydrous
medium and an alkyl fluoride as alkylating agent; in this case
the acid catalyst may promote undesired isomerization reaction
and consequently low or erratic yields [3].
In response to environmental issues, new partially fluori-
nated hydrofluoroethers (HFEs) and a–v hydrofluoropo-
lyethers (HFPEs, H-Galden ZTTM) have been recently
studied and successfully commercialized as CFCs substitutes
[1–3]. This class of compounds does not contain chlorine
atoms, therefore it does not contribute to ozone depletion. In
addition, good solvent property, low toxicity, [4] and low global
warming potentials (GWPs) [5] are the key features of this
promising category of compounds.
Since the recognition of these appealing properties as
solvent and refrigerant combined with low GWPs, HFEs
characterization, applications and preparation methodologies
have been the subjects of many publications and patents in the
specialized literature. HFE compounds can be prepared through
direct fluorination with elemental fluorine of hydrogenated
ethers [6], but this methodology results in isomerization and a
very exothermic fluorination reaction. Alternatively, HFEs can
be prepared through the alkylation of perfluoroacyl fluorides or
ketones in the presence of a stoichiometric amount of
Herein we report the use of alkyl fluoroformates RHOC(O)F
as a new family of alkylating agents. Perfluoroacyl fluorides
and selected perfluoroketones are alkylated to hydrofluor-
oethers RF–O–RH in good yields. Selected fluoroolefins are
alkylated to hydrofluoroalkanes RF–RH.
Potassium fluoride and cesium fluorides catalysts in glymes
at 50–100 8C are the preferred experimental conditions
adopted. Carbon dioxide is the only side product formed in
the reaction and the unreacted alkylating reagent can be
removed easily by standard distillation. Consequently, the
reaction is particularly clean and work up with a large amount
of partially reacted solid metal fluoride is avoided. For these
reasons this synthetic methodology has all the characteristics to
be successfully developed.
* Corresponding author. Tel.: +39 02 2399 3029; fax: +39 02 2399 3080.
E-mail address: walter.navarrini@polimi.it (W. Navarrini).
0022-1139/$ – see front matter # 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2005.09.005

M. Galimberti et al. / Journal of Fluorine Chemistry 126 (2005) 1578–1586
1579
2. Results and discussion
that gives better yields in hydrofluoroethers RF–CF2O–RH
[11,19].
2.1. Reaction stoichiometry and starting materials
The alkylation reaction to synthesize hydrofluoroethers has
been recently described in the patent literature by Navarrini
et al. [11] and it is reported in Eq. (1).
(3)
Perfluoroalkoxides 3 are known compounds characterized
by low nucleophilicity [4] and they decompose to acylfluorides
and fluoride ions, generally above room temperature, as shown
in Eq. (3). Even though their low stability and reactivity have
reduced the number of synthetic applications, perfluoroalk-
oxides 3 are important industrial intermediates in the
oligomerization of perfluoro epoxides [20], as well as in the
synthesis of hypofluorites and perfluoro vinylethers [21].
The second step in the alkylation reaction pathway is a
nucleophilic addition of the perfluoroalkoxide 3 to the
fluoroformate 2 directly forming the hydrofluoroether RF–O–
RH 4 or through the carbonate supposed intermediate 5
followed by a second nucleophilic substitution as described in
Scheme 1 paths (a) and (b), respectively.
(1)
The perfluoroacylfluorides
standard literature methodology [12–17].
1 are prepared following
The fluoroformate 2 can be prepared conveniently by reacting
carbonyl difluoride with the appropriate alcohols as shown in
Eq. (2). The experimental conditions adopted are a variation of
the methodology described in the patent literature [18].
There is some experimental evidence that supports both
pathways. For example path (a) is supported by the
experimental reaction with fluoride ions in the absence of
acylfluorides; in these conditions methylfluoroformate CH3O-
C(O)F 6 reacts with fluoride ions giving fluoromethane 7 as
shown in Eq. (4). Thus methyl fluoroformate 6 can operate
directly as an alkylating reagent, since in this condition the
supposed intermediate carbonate 5 cannot be formed.
(2)
2.2. Reaction mechanisms
The first step of the acylfluoride alkylation reaction shown in
Eq. (1) is the formation of the fluorinated alkoxides 3 as shown
in Eq. (3). Polar aprotic solvents are required for the formation
of fluorinated alkoxides 3, in particular tetraglyme is the solvent
This reaction has been cleverly exploited for the direct
preparation of alkyl fluorides from fluoroformate ester [22].
Scheme 1.

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M. Galimberti et al. / Journal of Fluorine Chemistry 126 (2005) 1578–1586
following the alkylation through a 19F NMR experiment, the
reaction between fluoroformate 6 and perfluoro-isobutyryl-
fluoride 8 at low temperature (50 8C) and low conversion (3%)
gives the ether (CF3)2CFCF2OCH3 4.3 as the only product since
the very beginning of the reaction. The conversion of the
reagents to the ether 4.3 (CF3)2CFCF2OCH3 increases by
increasing the temperature and the reaction time with a
selectivity of 95% (Run 1 of Table 1). Above 150 8C the ether
4.3 starts to decompose due to the presence of fluoride anions in
the reaction media, giving fluoromethane 7 and the starting
perfluoro-isobutyrylfluoride 8 as described in Scheme 3.
Path (b) is supported by the alkylation of TFE with
CH3OC(O)F in presence of fluoride ions (Run 5 of Table 2).
This reaction gives the methyl ester of the perfluoro propionic
acid 9 as shown in Scheme 4, where the nucleophilic attack
occurs to the carbonyl site.
(4)
According to Eq. (4), the reaction between perfluoroalk-
oxide 3 and fluoroformate 2 follows pathway (a) of Scheme 1
through the reaction mechanism described in Scheme 2 below.
Path (a) is also supported by the lack of experimental
evidence for the supposed fluoro-carbonate intermediate 5,
which has never been observed in the experimental conditions
adopted even at low acylfluoride conversion. In particular,
Similarly fluorocarbanions generated by the addition of
anions to the fluoro olefin have been trapped by dimethyl
carbonate forming fluoro esters and ketones [23].
Scheme 2.
Scheme 3.
Scheme 4.
Table 1
Preparation of selected HFEs through acylfluorides alkylation
b,c
Run
Acylfluoride 1
Fluoroformate 2
HFE 4 (characterization)a
Conv.%
Sel.%c
1
2
3
4
5
6
7
8
9
(CF3)2CFC(O)F
CH3OC(O)F
(CF3)2CFCF2–OCH3 4.3
(CF3O)(CF3)CFCF2–OCH3 4.4
CF3CF2CF2–OCH3 4.5
(CF3O)(CF3)CFCF2–OCH2CH3 4.6
(CF3O)(CF3)CFCF2–OCH(CH3)2 4.7
(CF3O)(CF3)CFCF2–OCH2CH CH2 4.8
(CF3O)(CF3)CFCF2–OCH2CH2Cl 4.9
–
75
76
85
79
66
84
70
0
95
95
96
96
82
97
30
0
(CF3O)(CF3)CFC(O)F
CF3CF2C(O)F
CH3OC(O)F
CH3OC(O)F
(CF3O)(CF3)CFC(O)F
(CF3O)(CF3)CFC(O)F
(CF3O)(CF3)CFC(O)F
(CF3O)(CF3)CFC(O)F
(CF3O)(CF3)CFC(O)F
(CF3O)(CF3)CFC(O)F
CH3CH2OC(O)F
(CH3)2CHOC(O)F
CH2 CHCH2OC(O)F
CH2ClCH2OC(O)F
CF3CH2OC(O)F
CFCl2CH2OC(O)F
–
0
0
a
See experimental Sections 4.3–4.9.
b
c
The acylfluoride present as alkoxide at the end of the reactions has been considered as unreacted reagent.
The alkylation conversion (Conv.%) and selectivity (Sel.%) were determined with respect to reacted acylfluoride and isolated HFEs compared to the initial and
reacted acylfluoride, respectively.

M. Galimberti et al. / Journal of Fluorine Chemistry 126 (2005) 1578–1586
1581
Table 2
Selected HFEs and HFCs from perfluoroketones and perfluoro olefins alkylation
a,b
Run
Pro-nucleophile
(CF3)2C
Formate
Alkylated product
Conv.%
Sel. %b
1
2
3
4
5
O
CH3OC(O)F
CH3OC(O)F
CH3OC(O)F
CH3OC(O)F
CH3OC(O)F
(CF3)2CF–OCH3 4.17
(CF3O)(CF3)CFCF2–OCH3 4.4
(CF3)2C(CH3)CF2CF2CF3
91
100
100
100
40
100
25
[(CF3O)(CF3)CF]2C(O)
CF2 CF–CF3
c
52
(CF3)2CFCF CFCF3
CF2 CF2
(CF3)2C(CH3)CF2CF2CF3
CF3CF2C(O)OCH3
89
70
a
The acylfluoride present as alkoxide at the end of the reactions has been considered as unreacted reagent.
b
The alkylation conversion (Conv.%) and selectivity (Sel.%) were determined with respect to reacted acylfluoride and isolated HFEs compared to the initial and
reacted acylfluoride, respectively.
c
The product has been identified by comparison of known compound [25].
Path (b) is also supported by literature data where
fluoroformate 2 acts as acylating reagent, in particular
enolizable hydrogenated alkoxy and enol aldehydes are
converted to the corresponding carbonates by treatment with
hydrogenated chloro- or fluoro-formates by nucleophilic attack
to the carbonyl group –COF [24].
The alkylation of TFE with CH3OC(O)F 6 gives the methyl
ester of perfluoropropionic acid 9 following the reaction
Scheme 4 proposed above.
This different behavior of TFE compared with HFP may be
explained by the lower tendency to dimerize of TFE with
respect to HFP and by the higher nucleophilicity and smaller
(ꢀ)
Perfluoroketones have been investigated and they are also
alkylated. Perfluoroacetone reacts with fluoroformate 6
giving the ether 4.17 as shown in Eq. (5) below and Run 1
of Table 2.
steric hindrance of the carbanion CF3CF2
formed with
fluoride anions from TFE in comparison to the (CF3)2CF(ꢀ)
,
[(CF3)2C–CF2CF2CF3](ꢀ) carbanions formed from HFP. This
diversity also suggests that the alkylating pathway (a) or the
acylating pathway (b) described in Scheme 1 may be followed
depending on the nucleophilicity and steric hindrance of the
reagents as summarized in Scheme 7.
(5)
Similarly, it is well known that chloroformate-esters may
undergo alkylation or acylation reactions depending on the
nucleophile and on the reaction conditions adopted [27].
From the experimental data concerning the reactions with
fluoroformates 2 and nucleophiles, we have observed alkylation
in the case of fluoride and alkoxides 3 as nucleophiles through
the mechanism shown in Scheme 7 path (a); carbon alkylation
or carbon acylation in the case of carbanions as nucleophiles
through the mechanism shown in Scheme 7 path (a) or Scheme
7 path (b) respectively. See Tables 1–3 for summarized
experimental results.
In the case of highly hindered ketones, for example Run 2 of
Table 2, the alkylation with fluoroformate 6 takes place on the
acylfluoride produced in the catalytic reaction promoted by
fluoride anions on the perfluoroketone 10 as shown in Scheme 5
below.
In the reaction of hexafluoropropene (HFP) with fluor-
oformate 6 catalyzed by fluoride anions (Run 3 of Table 2), the
HFP dimerization is observed and the alkylation takes place
only on the HFP dimer 10, thus obtaining the HFC 11 as shown
in Scheme 6 below. This reaction has been observed as side
reaction in the preparation of carboxylic acid esters containing
the heptafluoroisopropyl groups employing HFP and alkyl-
fluoroformate under different experimental conditions [26].
Directly utilizing the HFP dimer 10, the expected alkylated
product 11 was observed as shown in Run 4 of Table 2.
2.3. Reaction potential
The alkylation reaction is extremely versatile, since a great
variety of perfluoro unsaturated compounds can be active as pro-
nucleophiles through the fluoride addition reaction, in order
Scheme 5.

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M. Galimberti et al. / Journal of Fluorine Chemistry 126 (2005) 1578–1586
Scheme 6.
methyl, ethyl as well as allyl fluoroformates as shown in
Tables 1 and 3.
Decreasing the electronic density on the a carbon of the
fluoroformate Ca–OCOF by increasing the electronegativity of
thesubstituents on the Ca from –CH3, –CH2Cl, –CF2Cl and –CF3
decreases conversion and selectivity of the reaction to ether
products (Table 1, Runs 4, 7, 9 and 8 respectively). In the cases of
substituents –CF2Cl and –CF3 the reaction does not take place.
This may indicate a lower alkylating power for electron deficient
fluoroformates, that is consistent with path (a) of Scheme 7.
The results of the alkylation reactions of high boiling Z-
perfluoropolyether (Z-PFPE) mono-acylfluoride 12 CF3O–
(CF2CF2O)m(CF2O)n–CF2C(O)F with average molecular
weight of 590 (Z-MAF; MW = 590) and Z-perfluoropolyether
(Z-PFPE) di-acylfluoride 13 FC(O)CF2O–(CF2CF2O)m(C-
F2O)n–CF2C(O)F with average molecular weight of 620 (Z-
DAF; MW = 620) are reported in Table 3.
Scheme 7.
to generate the proper nucleophilic reagent. Perfluoroacylfluor-
ides perfluoroolefins, perfluoroketones, can be successfully
alkylated by means of the fluoride-catalyzed fluoroformates
alkylating reaction as shown in Tables 1–3. In addition, the
great variety of fluoroformate alkylating reagents further
improves the utility of this straightforward alkylating reaction.
Examples of successfully employed fluoroformates are
The allylation reaction of the Z-perfluoropolyether mono-
acylfluoride 12 is shown in Eq. (6).
(6)
Table 3
Preparation of selected HFEs through perfluoropolyether acylfluorides alkylation
Run
Acylfluoride 1
Fluoroformate 2
HFE 4 (characterization)a
Conv. %b,c
Sel.%c
1
2
3
4
5
6
7
(Z-DAF) MW = 620d
(Z-MAF) MW = 590e
(Z-DAF) MW = 620
(Z-MAF) MW = 590
(Z-MAF) MW = 590
(Z-DAF) MW = 620
(Z-MAF) MW = 590
CH3OC(O)F
CH3O–(Z-PFPE)–OCH3 4.10
CF3O–(Z-PFPE)–OCH3 4.11
90
97
96
82
90
90
98
100
100
100
100
100
100
100
CH3OC(O)F
CH3CH2OC(O)F
CH3CH2OC(O)F
(CH3)2CHOC(O)F
CH2 CHCH2OC(O)F
CH2 CHCH2OC(O)F
CH3CH2O–(Z-PFPE)–OCH2CH3 4.12
CF3O–(Z-PFPE)–OCH2CH3 4.13
CF3O–(Z-PFPE)–OCH(CH3)2 4.14
CH2 CHCH2O–(Z-PFPE)–OCH2CH CH2 4.15
CF3O–(Z-PFPE)–OCH2CH CH2 4.16
a
See experimental Sections 4.10–4.16.
b
c
The acylfluoride present as alkoxide at the end of the reactions has been considered as unreacted reagent.
The alkylation conversion (Conv.%) and selectivity (Sel.%) were determined by 1H NMR and 19F NMR analyses with respect to the initial acylfluoride and
reacted acylfluoride, respectively.
d
(Z-DAF) MW = 620: perfluoropolyether di-acylfluoride FC(O)CF2O–(CF2CF2O)m(CF2O)n–CF2C(O)F with average molecular weight of 620.
e
(Z-MAF) MW = 590: perfluoropolyether mono-acylfluoride CF3O–(CF2CF2O)m(CF2O)n–CF2C(O)F with average molecular weight of 590.

M. Galimberti et al. / Journal of Fluorine Chemistry 126 (2005) 1578–1586
1583
fluoro-ketones has been found. A great variety of efficient
fluoroformates alkylating reagents highlights the utility of this
straightforward reaction, which is performed in polar aprotic
solvents and is promoted by catalytic amounts of fluoride
anions.
4. Experimental
4.1. Safety precautions, general methods and materials
4.1.1. Safety precautions
Perfluoroacylfluorides and fluoroformates react with moist-
ure developing HF, some toxicity information on these
chemical categories are available in Houben-Weyl [28].
Fig. 1. Differences in pressure D(P ꢀ P0) as a function of the reaction time for
four selected fluoroformates ROC(O)F with R = CH3–, CH3CH2–, (CH3)2CH–
and CH2 CH–CH2– at temperature 100 8C. D(P ꢀ P0) = difference in pressure
P(t) ꢀ P(t0); P(t) = pressure at 100 8C at the reaction time t; P(t0) = pressure at
100 8C at the reaction time t = 0 during the alkylation reactions of Z-PFPE
mono-acylfluorides 12.
4.1.2. 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 measured volumes assuming
ideal gas behavior. 19F NMR spectra were recorded on Varian
200 MHz spectrometer, chemical shifts are expressed as d
values with CFCl3 as an internal reference (ppm = 0). 1H NMR
spectra were recorded on Varian 200 MHz spectrometer,
chemical shifts are expressed as d values with respect to
TMS (ppm = 0) in CDCl3 as solvent. Mass spectra were
performed on a Varian Mat CH-A spectrometer in the electron
impact mode at ionization energy of 70 eV.
As shown in Fig. 1, the relative pressure increase during the
alkylation reactions of the Z-PFPE mono-acylfluorides 12
CF3O–(CF2CF2O)m(CF2O)n–CF2C(O)F with selected fluoro-
formates RHOC(O)F can be reasonably due to the carbon
dioxide evolution during the alkylation reaction.
In Fig. 1 the differences in pressure D(P ꢀ P0) as a function
of the time between the pressure P at the time t and the initial
pressure P0 at the initial time t0 for four selected fluoroformates
RHOC(O)F with RH = CH3–; CH3CH2–; (CH3)2CH– and
CH2 CH–CH2– are reported.
As shown in Fig. 1, according to the carbon dioxide
evolution, the difference D(P ꢀ P0) increases with reaction
time, indicating that the reactivity of the fluoroformates here
investigated follows the order:
4.1.3. Materials
Chemicals obtained from commercial sources were directly
utilized unless mentioned.
CH3OCðOÞF > CH2¼CHꢀCH2ꢀOCðOÞF > CH3CH2OCðOÞF > ðCH3Þ2CHOCðOÞF
ꢁ Perfluoroacylfluorides were prepared according to standards
methods described in the literature [12,13].
ꢁ The Z-PFPE di-acylfluoride 13 F(O)CCF2O–(CF2CF2O)m(C-
F2O)n–CF2C(O)F (Z-DAF) was obtained by reaction of
tetrafluoroethylene (TFE) with oxygen in an inert solvent at
low temperature using UV irradiation to give a peroxidic
perfluoropolyether precursor followed by the reductive
cleavage of the peroxide bonds with hydrogen over a
suitable catalyst to yield essentially (Z-PFPE) di-acylfluoride
products 13 [14–16].
ꢁ The Z-PFPE mono-acylfluoride 12 CF3O–(CF2CF2O)m(C-
F2O)n–CF2C(O)F (Z-MAF) was prepared with good selec-
tivity by direct fluorination of perfluoropolyether
diacylfluoride 13 with elemental fluorine in the presence
of a catalyst metal fluoride MF (e.g. CsF, KF) according to a
new process discovered by Solvay Solexis [17]. The Z-PFPE
mono-acylfluoride product 12 was then separated and
purified by fractional distillation from the neutral perfluor-
Scheme 8.
Since the allyl fluoroformate CH2 CH–CH2–OC(O)F is
found to be more reactive than the corresponding ethyl and iso-
propyl fluoroformates, a possible SN20 mechanism may explain
the chemical reactivity increase of the latter and contemporarily
confirm path (a) of the reaction mechanism, as shown in
Scheme 8 below.
3. Conclusions
An innovative fluoride catalyzed synthetic methodology for
the alkylation of the anions generated through fluoride ion
addition to perfluoro-acylfluorides, perfluoro-olefins and per-

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M. Galimberti et al. / Journal of Fluorine Chemistry 126 (2005) 1578–1586
opolyether compounds CF3O–(CF2CF2O)m(CF2O)n–CF3
present in the final crude mixture.
selectivity (Sel.%) were determined with respect to reacted
acylfluoride and isolated HFEs compared to the initial and
reacted acylfluoride, respectively.
ꢁ Alkyl fluoroformates were prepared by a literature modified
procedure described below [18]. In a typical run, in a 150 ml
autoclave equipped with a magnetic stirrer and a pressure
transducer, the desired anhydrous alcohol (100 mmol) and
NaF (150 mmol) were charged in dry-box atmosphere. After
removing the incondensable gases by vacuum at ꢀ196 8C and
10ꢀ3 mbar, carbonyl fluoride (125 mmol) was condensed in
the autoclave cooled at liquid nitrogen temperature.
4.2.2. General alkylation procedure for high boiling
perfluoropolyether acylfluorides
In a typical run, a 25 ml autoclave equipped with a magnetic
stirrer and a pressure transducer, dry CsF (1,0 mmol) (Aldrich
Co. title 99.9%), dry tetraglyme (1.0 g) and perfluoropolyether
acylfluoride (4.0 mmol) were charged in dry-box atmosphere.
Afterremovingtheincondensablegasesbyvacuumat10ꢀ3 mbar
and ꢀ196 8C, fluoroformate (8.0 mmol) was added. The reaction
mixture was heated to 100 8C by an oil bath and kept under
stirring at this temperature for 48–72 h. When the reaction was
finished, methanol (1.0 g) was condensed in the autoclave. After
elimination of the gaseous products (CO2, HF) by vacuum, the
fluorinated phase was recovered and washed with water. The
alkylation conversion (Conv.%) and selectivity (Sel.%) were
determined by 1H NMR and 19F NMR analyses with respect to
the initial acylfluoride and reacted acylfluoride, respectively.
The charged autoclave was allowed to warm slowly up to
room temperature; during this phase a pressure increase due to
the low boiling point COF2, followed by a sudden decrease of
the pressure due to the fast reaction between COF2 and the
alcohol were observed. To complete the absorption of the HF
formed on the solid NaF the reaction mixture was finally stirred
at room temperature overnight. At the end of the reaction, the
pressure inside the autoclave was essentially due to the excess
of carbonyl fluoride.
The alkyl fluoroformate was recovered by a trap-to-trap
distillation, the formation of the fluoroformate was confirmed
by NMR (a typical signal at ꢀ17 ppm of the fluorine FC(O)O–)
and IR (a typical strong band in the range 1830–1860 cmꢀ1
assigned to the carbonyl appeared). The yields and purity
4.3. Characterization of (CF3)2CFCF2OCH3
19F NMR: d ꢀ74.0 (6F, (CF3)2CF–, m); ꢀ82.5 (2F,
CFCF2O, m); ꢀ182.4 (1F, CFCF2, m). 1H NMR: d 3.7
(OCH3, s).
1
determined by GC, 19F and H NMR analysis were above 95
and 98%, respectively.
MS main fragmentations and relative intensity: 47 (6), 69
(68), 81 (100), 100 (13), 131 (10), 169 (25), 197 (28), 231 (10).
Using this procedure, the formates CH3OCOF, CH3CH2O-
COF, (CH3)2CHOCOF, CH2 CHCH2OCOF, CH3CH2OCH2 -
CH2O-COF, CH2ClCH2OCOF, CF3CH2OCOF and CF2-
ClCH2OCOF were synthesized to be tested as alkylating
reagents.
4.4. Characterization of (CF3O)(CF3)CFCF2OCH3
19F NMR: d ꢀ53.9 (3F, CF3O, s); ꢀ80.7 (3F, CF3CF, s);
ꢀ88.4 (2F, CFCF2O, s); ꢀ146.0 (1F, CFCF2, s). 1H NMR: d 3.7
(OCH3, s).
4.2. General alkylating procedures
MS main fragmentations and relative intensity: 47 (26), 69
(100), 81 (99), 100 (7), 119 (16), 131 (30), 147 (9), 181 (13).
In the alkylating reactions the formation of one mole of
carbon dioxide for each mole of alkylated product (e.g.
hydrofluoroethers RF–O–RH, hydro fluoro alkanes RF–RH) is
always observed independently by the reactants and reaction
products, therefore the progress of the reaction can be
conveniently followed by carbon dioxide formation and
consequent pressure increase.
4.5. Characterization of CF3CF2CF2OCH3
19F NMR: d ꢀ82.2 (3F, CF3CF2, m); ꢀ90.0 (2F, CF2CF2O,
1
m); ꢀ130.1 (2F, CF3CF2CF2, m). H NMR: d 3.7 (OCH3, s).
4.6. Characterization of (CF3O)(CF3)CFCF2OCH2CH3
4.2.1. General alkylation procedure for low boiling
acylfluorides, ketones and olefins
19F NMR: d ꢀ53.9 (3F, CF3O–, s); ꢀ80.6 (3F, CF3CF, s);
ꢀ85.5 (2F, CFCF2O, s); ꢀ146.0 (1F, CFCF2, s). 1H NMR: d 4.1
(2H, OCH2CH3, q, J = 6.8 Hz); 1.3 (3H, CH2CH3, t,
J = 6.8 Hz).
In a typical run, a 50 ml autoclave equipped with a magnetic
stirrer and a pressure transducer, dry CsF (2.5 mmol) (Aldrich
Co. title 99.9%) and dry tetraglyme (2.0 g) were charged in dry-
box atmosphere. After removing the incondensable gases by
vacuum at 10ꢀ3 mbar and ꢀ196 8C, acyl-fluoride (15 mmol)
and formate (15 mmol) were condensed in the autoclave at
liquid nitrogen temperature. The reaction mixture was heated to
100 8C by an oil bath and kept under stirring at this temperature
for 48 h. The reaction products were separated by trap to trap
distillation obtaining the hydrofluoroether. Unreacted acyl-
fluoride was recovered as a glyme solution of perfluoroalkoxide
salt RFOꢀCs+. The alkylation conversion (Conv.%) and
MS main fragmentations and relative intensity: 47 (19), 69
(100), 95 (11), 169 (17), 213 (7).
4.7. Characterization of (CF3O)(CF3)CFCF2OCH(CH3)2
19F NMR: d ꢀ53.8 (3F, CF3O–, s); ꢀ80.5 (3F, CF3CF, s);
ꢀ83.0 (2F, CFCF2O, s); ꢀ145.8 (1F, CFCF2, s). 1H NMR: d 4.7
(1H, OCH(CH3)2, heptett, J = 6.2 Hz); 1.3 (6H, OCH(CH3)2, d,
J = 6.2 Hz).

M. Galimberti et al. / Journal of Fluorine Chemistry 126 (2005) 1578–1586
1585
MS main fragmentations and relative intensity: 43 (100), 47
(88), 69 (100, 169 (44), 279 (79), 293 (5).
(OCF2CF2O); ꢀ89.2 (OCF2CF2OCH). 1H NMR: d 4.72 (1H,
OCH(CH3)2, m); 1.38 (6H, OCH(CH3)2, m).
4.8. Characterization of
(CF3O)(CF3)CFCF2OCH2CH CH2
4.15. Characterization of CH2 CHCH2O–
(CF2CF2O)m(CF2O)n–CF2CF2–OCH2CH CH2
19F NMR: d ꢀ53.9 (3F, CF3O, s); ꢀ80.6 (3F, CF3CF, s);
19F NMR: d ꢀ51.7, ꢀ55.3 (OCF2O); ꢀ88.4, ꢀ90.7
1
1
ꢀ85.2 (2F, CFCF2O, s); ꢀ146.0 (1F, CFCF2, s). H NMR: d
(OCF2CF2O); ꢀ91.1 (OCF2CF2OCH2CH CH2). H NMR:
5.95 (1H, CH2CH CH2, m); 5.41 (1H, CH2CH CH2, dd,
trans = 24.5 Hz); 5.34 (1H, CH2CH CH2, dd, Jcis = 16.5 Hz);
d 5.95 (OCH2CH CH2, m); 5.41 (1H, OCH2CH CH2, dd,
J
Jtrans = 24.5 Hz);
cis = 16.5 Hz); 4.54 (2H, OCH2CH CH2, dd, J = 5.49 Hz,
J = 1.1 Hz).
5.34
(1H,
OCH2CH CH2,
dd,
4.54 (2H, CH2CH CH2, dd, J = 5.49 Hz, J = 1.1 Hz).
MS main fragmentations and relative intensity: 39 (80), 41
(100), 69 (99), 100 (6), 107 (6), 292 (17).
J
4.16. Characterization of CF3O–(CF2CF2O)m(CF2O)n–
CF2CF2–OCH2CH CH2
4.9. Characterization of (CF3O)(CF3)CFCF2OCH2CH2Cl
19F NMR: d ꢀ53.9 (3F, CF3O, s); ꢀ80.4 (3F, CF3CF, s);
ꢀ85.5 (2F, CFCF2O, s); ꢀ146.0 (1F, CFCF2, s). 1H NMR: d 4.7
(2H, OCH2CH2Cl, m); 3.8 (2H, OCH2CH2Cl, m).
MS main fragmentations and relative intensity: 47 (11), 69
(100), 169 (23), 213 (11).
19F NMR: d ꢀ55.3 (OCF2O); ꢀ56.2 (CF3OCF2CF2O);
ꢀ57.8 (CF3OCF2O); ꢀ87.5 (CF3CF2O); ꢀ88.4, ꢀ90.7
1
(OCF2CF2O); ꢀ91.3 (OCF2CF2OCH2CH CH2). H NMR:
d 5.95 (1H, OCH2CH CH2, m); 5.41 (1H, OCH2CH CH2, dd,
OCH2CH CH2,
J
trans = 24.5 Hz);
5.34
(1H,
dd,
Jcis = 16.5 Hz); 4.54 (2H, OCH2CH CH2, dd, J = 5.49 Hz,
J = 1.1 Hz).
4.10. Characterization of CH3O–(CF2CF2O)m(CF2O)n–
CF2CF2–OCH3
4.17. Characterization of (CF3)2CFOCH3
19F NMR: d ꢀ51.7, ꢀ55.3 (OCF2O, d.m); ꢀ88.4, ꢀ90.7
(OCF2CF2O); ꢀ94.2 (OCF2CF2OCH3). 1H NMR: d 3.7
(OCF2CF2OCH3).
19F NMR: d ꢀ79.4 (6F, (CF3)2, s); ꢀ145.1 (1F, CFOCH3, s).
1H NMR: d 3.8 (OCH3, s).
4.11. Characterization of CF3O–(CF2CF2O)m(CF2O)n–
CF2CF2–OCH3
Acknowledgements
The authors wish to thank Massimiliano Lorusso for the
experimental work, Emma Barchiesi for the helpful analysis
discussions and Solvay Solexis for permission to publish this
work.
19F NMR: d ꢀ51.7, ꢀ55.3 (OCF2O); ꢀ56.2 (CF3OCF2-
CF2O); ꢀ57.8 (CF3OCF2O); ꢀ88.4, ꢀ90.7 (OCF2CF2O);
1
ꢀ94.6 (OCF2CF2OCH3). H NMR: d 3.76 (–OCH3, m).
References
4.12. Characterization of CH3CH2O–
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