- Email: [email protected]
Synthesis of 3,3,3-trifluoropropene from vinylidene fluoride
JournalofFluorine C/lemistry, 12(1978)411 479 OElsevier Sequoia %A.,Lausanne ~ Printed intheNetherlands
471
Received: May 16,1978
SYNTHESIS
OF 3,3,3-TRIFLUOROPROPENE
FROM
VINYLIDENE
FLUORIDE-F
A. E. FEIRING
Central
Research
Experimental Wilmington,
& Development
Station, Delaware
Department,
E. I. du Pont de Nemours
& Co.,
Inc.
19898
SUMMARY
3,3,3-Trifluoropropene via
3,3,3-trifluoropropyl
ether
from
acetate
as key intermediates.
conjugate
addition
is obtained
The
of FCH20R
HF, paraformaldehyde
under
mild
conditions
or 3,3,3-trifluoropropyl intermediates
(R = COCH3,
CH3)
were
prepared
generated
and HOR to vinylidene
methyl by
in situ --
fluoride.
INTRODUCTION 3,3,3_Trifluoropropene
(,&) is a useful
for the preparation
of a variety
syntheses
been reported,
of & have
of fluorinated
tion of 1,1,1,3-tetrachloropropane on the reaction
of acrylic
These
often
are
reactions
inconvenient
paper,
to run,
alternative
t
Contribution
No
2575
sulfur
material
compounds.
based
or related
highly
especially
syntheses
are reported.
often
acid with
require
starting
on the fluorinacompounds lf2 or
tetrafluoride.
specialized
equipment
on laboratory
scale.
of ,& based
Many
on vinylidene
and In this
fluoride
472 RESULTS The first reaction acid
of vinylidene
in hydrogen
in 30% yield ether
approach
to & was based
fluoride
fluoride
together
with paraformaldehyde
to give
with
on the known
about
4,5 and acetic
3,3,3-trifluoropropyl
acetate
15% of 3,3,3-trifluoropropyl
(2).
s CF2
These
= CH2
compounds
However,
+ HCHO
were
pyrolysis
an essentially and acetic
difficult
to separate
of the mixture
quantitative
yield
in a flow
+
by distillation. system
at 450' gave
of & from 2 plus unchanged
2
acid.
Although
short
clearly
suffers
Efforts
to increase
isolated
CF3CH2CH20CCH3
+ CH3COOII -1 HF ---->
from
from
and convenient,
the low yield the yield
this reaction
polycondensation
products
included,
I:
CF3CH2CH2CCCH2CH20CCH3
of &
j$ in the first
in addition
$,, 2, and ,$.
::
CF3CH2CH20CH2CH2COOH
of acetate
were unsuccessful.
CF3CH2CH20CCH2CH20CH2CH2CF3
P
this synthesis
By-products to 2, the
step
413 An alternate
synthesis
reaction
of vinylidene
methanol
in hydrogen
propyl
ether
Efforts
Reaction
paraformaldehyde gave methyl
(x) in 60% yield
based
on vinylidene
crack
gave very
CF2=CH2
pure
+ CH30H
fluoride. a variety
treatment
of 2 with
hydrogen
converted
sodium
hydroxide
+ CH20
+ BF ~
under
E.
phase
quantitative
of bromide
it to the bromide
& in essentially
----------> sulfolane
2 + HBr
3,3,3-trifluoro-
to & over
at 120° cleanly aqueous
and
;I directly
However,
of 5 with
conditions
with
the known 4,s
which
failed.
in sulfolane
fluoride
with
fluoride
to thermally
catalysts
of & began
transfer yield.
> CF3CH2CH20CH3
CF3CH2CH2Br 8 %
8 ri,
e> II2 0
1 'L
Reaction in hydrogen
of vinylidene
fluoride
15% of methyl
CF2=CH2
fluoride
gave ;I in 50% yield
3-methoxypropionate
+
with
(CH30j2CH2
dimethoxymethane
together
with
about
(2,.
HF p>
s
1 + CH30CCH2CH20CH3 9 ?,
DISCUSSION The three
step
provides
a convenient
reaction
proceeds
sequence synthesis
(vinylidene
fluoride+
of trifluoropropene.
in good to excellent
yield
under
,7+ t+$) Each
mild
conditions
474
of temperature purification
and pressure.
The
of intermediates
The by-products previously
reported4
chloride.
The overall
sequence
can be run without
to give pure
final
product.
$, $,, and ,Q are analogous
from
a similar
mechanism
reaction
to those
using
of the conjugate
vinylidene addition
process
compounds
pre-
has been discussed.4 NMR data pared
Table
as part
for 2, 2, t, 4, and
of this work
some related
are collected
in Table
1.
1
NMR Spectra
of CF3CH2CH2X
X
Derivativesa
6 (CH2X)
6X
6CF3
4.25
2.01
-65.19
3.68
--_-
-65.63
OCH3
3.58
3.33
-65.56
Br
3.45
_---
-66.80
Clb
3.66
_-_-
-66.31
NHZC
2.91
1.67
-65.50
OAc 0 (CH2)
a.
2CF3
In CDC13,
ppm
from TMS
(proton)
protons
adjacent
quartet
(J zz 11 Hz) centered
to CF3 appear
or CFC13
(fluorine).
as a tripled
at cd.
b.
Prepared
according
to Reference
1.
C.
Prepared
according
to Reference
1.
(JZ
6.5
The Hz)
6 2.3.
EXPERIMENTAL Anhydrous Air
Products.
as received. instrument
hydrogen
All other Proton
fluoride
reagents
NMR spectra
in CDCl 3 with
was used as received
were were
commercial obtained
TMS as internal
from
samples,
used
on a Varian
A-60
standard.
Fluorine
475 NMR spectra
were
obtained
at 94.1 MHz using obtained
CFC13
tissue,
Laboratory
Hydrogen
contact
work
with
instrument
operated
standard.
Glpc data were
instrument
using
the indicated
60 g
of acetic
(1.8 moles)
mixture
were
to 30' and
were
After
blown
organic
filtered,
giving
the liquid
and
Addition
3,3,3-trifluoropropyl
With
liquid.
25 g of pot residue. NMR
(cf. Table
acetate
cooled
gave
N2 and
with dry
ice/
The resulting Vinylidene 115 g fluoride
the contents
dried
column
clothing
and 150 g (2.5
of the vinylidene
separated,
a 6" Vigreaux
with
at 15 psi until
overnight
148 g of colorless
and fluorine
was swept
by the slow addition was
in an efficient
vigorously..
300 g of ice.
burns.
(2)
160 g of HF.
stirred
to
and protective
was closed,
with
standing
onto
layer
through
bp 100-108° by proton
shield
to the autoclave
was neutralized
An upper
only
of paraformaldehyde
The clave
absorbed.
3/4 hr.
autoclave
face
autoclave
and charged
was admitted
required
full
Hastelloy
acid.
was warmed
fluoride
be conducted
(2 mole)
evacuated
mixture
HF should
corrosive
slow-healing
of 3,3,3-Trifluoropropylacetate
with
acetone,
is extremely
in painful,
wearing
A 1 1 stirred charged
fluoride
resulting
with
operator
Preparation
moles)
5700A
XL-100
and conditions.
Caution!
hood
as internal
on a Hewlett-Packard
columns
human
on a Varian
strong
of the
cooling
the
of 50% aq KOH. over MgS04
and
Distillation
of
120 g of distillate
The distillate 1) as a mixture
was analyzed of 66% of
and 34% 3,3,3-trifluoropropyl
ether.
476
The combined distilled
through
pot residues
a short
from two runs
path distillation
of colorless
liquid,
liquid
a 10 ff x l/4 in 10% SE-30
using
two peaks Samples was
with
retention
of each were
identified
4.33
fluorine
(4H, m);
was
(6) 4.32
NMR
liquid
addition
time.
diluting ether
solution
A
filtered
identified
(IH, S),
3.73
(2H, m);
fluorine
Pyrolysis
5.9 min
proton
(68%)
component NMR
(6)
(2H, t), 2-O-2.9 The major
(3F).
proton
(2H, m),
2.05
of the pot residue
compounds
comnmr
(3H, S);
sample
Glpc analysis
of this material
of the distillate
were
with
with
The combined
with ether
as CF3CH2CH20CH2CH2COOH; (2H, t), 2.62
in
longer
was obtained
50 ml ether.
cone
by
The
The
HCl and extracted
extracts
in vacua -~
9 g of
showed
2 x 30 ml 5% aq KOH.
acidified
(2H, t), 3.68
gave
a third component.of
and concentrated
were dried
to 2.3 y of colorless proton
NMR
(6) 10.40
(2H, t), 2.0-2.8
NMR -65.35.
of 3,3,3-Trifluoropropylacetate
An 8" quartz mounted
of the
The minor
(2H, t), 2.60
(3F), -65.72
30.2 g
at 200' showed
(32%) and
glpc.
at 1.4 mm.
was extracted
2 x 30 ml ether.
liquid
column
(2H, t), 2.1-2.9
pure
KOH extracts
(MySOd) ,
analysis
as CF3CH2CH200CCH2CH200CCH3;
bp 90-95"
a 5 g sample
combined with
-65.52
distillation
to the above
retention
by prep
giving
-65.58.
Continued colorless
~lpc
of 3.9 min
(2H, t), 3.68
identified
nmr
times
obtained
(4H, t), 2.62
fluorine
at 4 mm.
head
as CF3CH2CH200CCH2CH20CH2CH2CF3,
(2H, t), 3.73
ponent
bp 85-95"
(48.8 g) were
in a vertical
tube packed electric
with
(4) silicon
furnace.
carbide
The base
chips
was
of the tube
477 was attached
to two traps,
second
cooled
funnel
was placed
was swept mixture
in dry
with
N
ice/acetone.
and the quartz
2
added
dropwise
After
the addition
flow of N2 for 2 hr. trap contained
The
The
ice water
of acetic
of Methyl
with
96 g
Hastelloy
(3 moles)
acetone,
and charged
evacuated
to 20° and
was admitted After
at 10 psi until
standing
overnight
of ice.
With
bubbling
in ammonia
dried
strong
over MgS04,
column
cooling gas.
gave
was
over
swept with
2 hr. a slow
The dry
ice
by glpc comparison Q column
with
at 60°.
identified
by proton
with
Ether was
swept with
cooled
with dry
vigorously.
Vinylidene
160 g (2.5 mole)
organic
had been
onto
was
(56%) of ether
through bp 60-62".
300 g by
separated,
205 g of crude
Distillation
absorbed.
was neutralized layer
ice/
fluoride
was discharged
the solution
of
The mixture
280 g of HF.
to give
N2 and
and 90 g (3 moles)
was closed,
A lower
ether. 179 g
autoclave
the solution
and filtered
3,3,3-trifluoropropyl Vigroux
stirred
A
and 2.
of methanol
The vessel
system
to 500°.
disconnected.
3,3,3-Trifluoropropyl
paraformaldehyde.
was warmed
the column
6.3 g of liquid acid
addition
The
funnel
on a 4 ft x l/8 in Poropak
A 1 1 stirred charged
the addition
traps were
trap contained
NMR as a mixture
column.
the
89% of 2 and 11% of 2 was
6.5 g of pure ,& identified sample
Preparation
from
was complete
pressure
tube was heated
of about
to the column
in ice water,
A constant
on top of the pyrolysis
(15 g) consisting
an authentic
the first cooled
methyl
a 6-inch
478 Preparation
of l-Bromo-3,3,3-trifluoropropane
A 200 ml Hastelloy of x and
60 ml of sulfolane.
ice/acetone
and charged
The resulting to room were
mixture
temperature
poured
washed
bomb was charged
over
twice
49 g of liquid.
with
48.6
g
was agitated
A lower over
mantle,
magnetic
a thermometer,
bottom
stirrer,
trap was cooled
acetone.
The system
flask
was charged
pellets, water.
with
trifluoroprqpane
additional
2 hr.
flushed
a tube
column
showed
and a peak
at 60').
complex
at -67.31
was separated
filtered
44 g
to gid
(83%) of
mole)
the dry which
leading
of sodium
was added
ice/
bottomed
hydroxide and 130 ml of
dropwise was
99% pure
by glpc
of the product
NMR.
over
stirred
isolated
in the proton
in the fluorine
in dry
to 55O and l-bromo-3,3,3-
ice trap was was
funnel,
to two traps.
The round
the mixture
An aliquot
absorption
addition
chloride
was heated
with a heating
the second
with N2.
(0.4 mole)
was complete, From
and
gave
pressure
in ice water,
solution
of 3,3,3-trifluoropropene
CDC13
with
(53.1 g, 0.3
the addition
Poropak
a constant
16 g
MgS04,
layer
from l-Bromo-3,3,3-
2 g of benzyltrimethylammonium The stirred
After
was
then cooled
of the autoclave
flask was equipped
and a condenser
The first
bromide
bp 60-62'.
Preparation of 3,3,3-Trifluoropropene .___ trifluoropropane A 250 ml round
in dry
of hydrogen
organic
of the liquid
1-bromo-3,3,3-trifluoropropane
cooled
at 120' overnight,
dried
Distillation
(0.6 mole)
The contents
and vented.
50 ml H20,
38.4 g (0.3 mole)
The bomb was closed,
100 g of ice.
with
with
1 hr.
for an
26 g (90%) (4 ft x 1/8ft)
dissolved
in
NMR at 6 5.4-6.2
479
REFERENCES R. N. Haszeldine, M. Nager,
J. Chem.
J. Amer.
J. A. Valicenti, 3,739,036
Chem.
R. L. Halm,
I. Morioka,
(CA 82, 139,283f); (CA 60,
9148f);
(CA 79,
Japan
French
1,343,392
and R. K. Freidlina,
Otdel
Khim
Nauk,
Stowe
and R. A. Davis,
W. C. Smith,
Sot. 82,
L. s. German 349
(December
Patent
L. I.
Akad.
22343);
21, 1974)
15, 1963)
V. N. Kost,
(CA 54,
Y.
Nauk
S.S.S.R.,
R. P. Ruh,
2,889,379
R. A.
(June 2, 1959)
543
and V. A. Engelhardt,
J. Amer.
(1960).
and
I. L. Knunyantz,
Angew.
Chem.
and
I. L. Knunyantz,
Zh. Vses,
Inter.
Ed. g,
(1969).
L. s. German
von D. I. Mendeleeva P.
U.S.
H. Wada,
1295a).
W. R. Hasek, Chem.
(1960)
U.S. Patent
(November
Izvest.
and
(1951).
52775g);
74,133,308
A. N. Nesmeyanov,
447
(1953); A. L. Henne
F. 0. Stark,
Zakharkin,
(CA 54,
3371
Sot. 11, 1042
(June 12, 1973)
Hiramatsu,
Sot.
Tarrant,
Chem.
356
A. M. Lovelace,
Sot. 77, 2783
A. V. Podol'skii, Izv Akad.
11,
Nauk
(1966)
Obshchestva.
(CA 65, 15215h).
and M. R. Lilyquist,
J. Amer.
(1953).
L. S. German,
SSSR,
Khim.
Ser. Khim.
and I. L. Knunyantz, 1575
(1966)
(CA 66:95004d)
471
Received: May 16,1978
SYNTHESIS
OF 3,3,3-TRIFLUOROPROPENE
FROM
VINYLIDENE
FLUORIDE-F
A. E. FEIRING
Central
Research
Experimental Wilmington,
& Development
Station, Delaware
Department,
E. I. du Pont de Nemours
& Co.,
Inc.
19898
SUMMARY
3,3,3-Trifluoropropene via
3,3,3-trifluoropropyl
ether
from
acetate
as key intermediates.
conjugate
addition
is obtained
The
of FCH20R
HF, paraformaldehyde
under
mild
conditions
or 3,3,3-trifluoropropyl intermediates
(R = COCH3,
CH3)
were
prepared
generated
and HOR to vinylidene
methyl by
in situ --
fluoride.
INTRODUCTION 3,3,3_Trifluoropropene
(,&) is a useful
for the preparation
of a variety
syntheses
been reported,
of & have
of fluorinated
tion of 1,1,1,3-tetrachloropropane on the reaction
of acrylic
These
often
are
reactions
inconvenient
paper,
to run,
alternative
t
Contribution
No
2575
sulfur
material
compounds.
based
or related
highly
especially
syntheses
are reported.
often
acid with
require
starting
on the fluorinacompounds lf2 or
tetrafluoride.
specialized
equipment
on laboratory
scale.
of ,& based
Many
on vinylidene
and In this
fluoride
472 RESULTS The first reaction acid
of vinylidene
in hydrogen
in 30% yield ether
approach
to & was based
fluoride
fluoride
together
with paraformaldehyde
to give
with
on the known
about
4,5 and acetic
3,3,3-trifluoropropyl
acetate
15% of 3,3,3-trifluoropropyl
(2).
s CF2
These
= CH2
compounds
However,
+ HCHO
were
pyrolysis
an essentially and acetic
difficult
to separate
of the mixture
quantitative
yield
in a flow
+
by distillation. system
at 450' gave
of & from 2 plus unchanged
2
acid.
Although
short
clearly
suffers
Efforts
to increase
isolated
CF3CH2CH20CCH3
+ CH3COOII -1 HF ---->
from
from
and convenient,
the low yield the yield
this reaction
polycondensation
products
included,
I:
CF3CH2CH2CCCH2CH20CCH3
of &
j$ in the first
in addition
$,, 2, and ,$.
::
CF3CH2CH20CH2CH2COOH
of acetate
were unsuccessful.
CF3CH2CH20CCH2CH20CH2CH2CF3
P
this synthesis
By-products to 2, the
step
413 An alternate
synthesis
reaction
of vinylidene
methanol
in hydrogen
propyl
ether
Efforts
Reaction
paraformaldehyde gave methyl
(x) in 60% yield
based
on vinylidene
crack
gave very
CF2=CH2
pure
+ CH30H
fluoride. a variety
treatment
of 2 with
hydrogen
converted
sodium
hydroxide
+ CH20
+ BF ~
under
E.
phase
quantitative
of bromide
it to the bromide
& in essentially
----------> sulfolane
2 + HBr
3,3,3-trifluoro-
to & over
at 120° cleanly aqueous
and
;I directly
However,
of 5 with
conditions
with
the known 4,s
which
failed.
in sulfolane
fluoride
with
fluoride
to thermally
catalysts
of & began
transfer yield.
> CF3CH2CH20CH3
CF3CH2CH2Br 8 %
8 ri,
e> II2 0
1 'L
Reaction in hydrogen
of vinylidene
fluoride
15% of methyl
CF2=CH2
fluoride
gave ;I in 50% yield
3-methoxypropionate
+
with
(CH30j2CH2
dimethoxymethane
together
with
about
(2,.
HF p>
s
1 + CH30CCH2CH20CH3 9 ?,
DISCUSSION The three
step
provides
a convenient
reaction
proceeds
sequence synthesis
(vinylidene
fluoride+
of trifluoropropene.
in good to excellent
yield
under
,7+ t+$) Each
mild
conditions
474
of temperature purification
and pressure.
The
of intermediates
The by-products previously
reported4
chloride.
The overall
sequence
can be run without
to give pure
final
product.
$, $,, and ,Q are analogous
from
a similar
mechanism
reaction
to those
using
of the conjugate
vinylidene addition
process
compounds
pre-
has been discussed.4 NMR data pared
Table
as part
for 2, 2, t, 4, and
of this work
some related
are collected
in Table
1.
1
NMR Spectra
of CF3CH2CH2X
X
Derivativesa
6 (CH2X)
6X
6CF3
4.25
2.01
-65.19
3.68
--_-
-65.63
OCH3
3.58
3.33
-65.56
Br
3.45
_---
-66.80
Clb
3.66
_-_-
-66.31
NHZC
2.91
1.67
-65.50
OAc 0 (CH2)
a.
2CF3
In CDC13,
ppm
from TMS
(proton)
protons
adjacent
quartet
(J zz 11 Hz) centered
to CF3 appear
or CFC13
(fluorine).
as a tripled
at cd.
b.
Prepared
according
to Reference
1.
C.
Prepared
according
to Reference
1.
(JZ
6.5
The Hz)
6 2.3.
EXPERIMENTAL Anhydrous Air
Products.
as received. instrument
hydrogen
All other Proton
fluoride
reagents
NMR spectra
in CDCl 3 with
was used as received
were were
commercial obtained
TMS as internal
from
samples,
used
on a Varian
A-60
standard.
Fluorine
475 NMR spectra
were
obtained
at 94.1 MHz using obtained
CFC13
tissue,
Laboratory
Hydrogen
contact
work
with
instrument
operated
standard.
Glpc data were
instrument
using
the indicated
60 g
of acetic
(1.8 moles)
mixture
were
to 30' and
were
After
blown
organic
filtered,
giving
the liquid
and
Addition
3,3,3-trifluoropropyl
With
liquid.
25 g of pot residue. NMR
(cf. Table
acetate
cooled
gave
N2 and
with dry
ice/
The resulting Vinylidene 115 g fluoride
the contents
dried
column
clothing
and 150 g (2.5
of the vinylidene
separated,
a 6" Vigreaux
with
at 15 psi until
overnight
148 g of colorless
and fluorine
was swept
by the slow addition was
in an efficient
vigorously..
300 g of ice.
burns.
(2)
160 g of HF.
stirred
to
and protective
was closed,
with
standing
onto
layer
through
bp 100-108° by proton
shield
to the autoclave
was neutralized
An upper
only
of paraformaldehyde
The clave
absorbed.
3/4 hr.
autoclave
face
autoclave
and charged
was admitted
required
full
Hastelloy
acid.
was warmed
fluoride
be conducted
(2 mole)
evacuated
mixture
HF should
corrosive
slow-healing
of 3,3,3-Trifluoropropylacetate
with
acetone,
is extremely
in painful,
wearing
A 1 1 stirred charged
fluoride
resulting
with
operator
Preparation
moles)
5700A
XL-100
and conditions.
Caution!
hood
as internal
on a Hewlett-Packard
columns
human
on a Varian
strong
of the
cooling
the
of 50% aq KOH. over MgS04
and
Distillation
of
120 g of distillate
The distillate 1) as a mixture
was analyzed of 66% of
and 34% 3,3,3-trifluoropropyl
ether.
476
The combined distilled
through
pot residues
a short
from two runs
path distillation
of colorless
liquid,
liquid
a 10 ff x l/4 in 10% SE-30
using
two peaks Samples was
with
retention
of each were
identified
4.33
fluorine
(4H, m);
was
(6) 4.32
NMR
liquid
addition
time.
diluting ether
solution
A
filtered
identified
(IH, S),
3.73
(2H, m);
fluorine
Pyrolysis
5.9 min
proton
(68%)
component NMR
(6)
(2H, t), 2-O-2.9 The major
(3F).
proton
(2H, m),
2.05
of the pot residue
compounds
comnmr
(3H, S);
sample
Glpc analysis
of this material
of the distillate
were
with
with
The combined
with ether
as CF3CH2CH20CH2CH2COOH; (2H, t), 2.62
in
longer
was obtained
50 ml ether.
cone
by
The
The
HCl and extracted
extracts
in vacua -~
9 g of
showed
2 x 30 ml 5% aq KOH.
acidified
(2H, t), 3.68
gave
a third component.of
and concentrated
were dried
to 2.3 y of colorless proton
NMR
(6) 10.40
(2H, t), 2.0-2.8
NMR -65.35.
of 3,3,3-Trifluoropropylacetate
An 8" quartz mounted
of the
The minor
(2H, t), 2.60
(3F), -65.72
30.2 g
at 200' showed
(32%) and
glpc.
at 1.4 mm.
was extracted
2 x 30 ml ether.
liquid
column
(2H, t), 2.1-2.9
pure
KOH extracts
(MySOd) ,
analysis
as CF3CH2CH200CCH2CH200CCH3;
bp 90-95"
a 5 g sample
combined with
-65.52
distillation
to the above
retention
by prep
giving
-65.58.
Continued colorless
~lpc
of 3.9 min
(2H, t), 3.68
identified
nmr
times
obtained
(4H, t), 2.62
fluorine
at 4 mm.
head
as CF3CH2CH200CCH2CH20CH2CH2CF3,
(2H, t), 3.73
ponent
bp 85-95"
(48.8 g) were
in a vertical
tube packed electric
with
(4) silicon
furnace.
carbide
The base
chips
was
of the tube
477 was attached
to two traps,
second
cooled
funnel
was placed
was swept mixture
in dry
with
N
ice/acetone.
and the quartz
2
added
dropwise
After
the addition
flow of N2 for 2 hr. trap contained
The
The
ice water
of acetic
of Methyl
with
96 g
Hastelloy
(3 moles)
acetone,
and charged
evacuated
to 20° and
was admitted After
at 10 psi until
standing
overnight
of ice.
With
bubbling
in ammonia
dried
strong
over MgS04,
column
cooling gas.
gave
was
over
swept with
2 hr. a slow
The dry
ice
by glpc comparison Q column
with
at 60°.
identified
by proton
with
Ether was
swept with
cooled
with dry
vigorously.
Vinylidene
160 g (2.5 mole)
organic
had been
onto
was
(56%) of ether
through bp 60-62".
300 g by
separated,
205 g of crude
Distillation
absorbed.
was neutralized layer
ice/
fluoride
was discharged
the solution
of
The mixture
280 g of HF.
to give
N2 and
and 90 g (3 moles)
was closed,
A lower
ether. 179 g
autoclave
the solution
and filtered
3,3,3-trifluoropropyl Vigroux
stirred
A
and 2.
of methanol
The vessel
system
to 500°.
disconnected.
3,3,3-Trifluoropropyl
paraformaldehyde.
was warmed
the column
6.3 g of liquid acid
addition
The
funnel
on a 4 ft x l/8 in Poropak
A 1 1 stirred charged
the addition
traps were
trap contained
NMR as a mixture
column.
the
89% of 2 and 11% of 2 was
6.5 g of pure ,& identified sample
Preparation
from
was complete
pressure
tube was heated
of about
to the column
in ice water,
A constant
on top of the pyrolysis
(15 g) consisting
an authentic
the first cooled
methyl
a 6-inch
478 Preparation
of l-Bromo-3,3,3-trifluoropropane
A 200 ml Hastelloy of x and
60 ml of sulfolane.
ice/acetone
and charged
The resulting to room were
mixture
temperature
poured
washed
bomb was charged
over
twice
49 g of liquid.
with
48.6
g
was agitated
A lower over
mantle,
magnetic
a thermometer,
bottom
stirrer,
trap was cooled
acetone.
The system
flask
was charged
pellets, water.
with
trifluoroprqpane
additional
2 hr.
flushed
a tube
column
showed
and a peak
at 60').
complex
at -67.31
was separated
filtered
44 g
to gid
(83%) of
mole)
the dry which
leading
of sodium
was added
ice/
bottomed
hydroxide and 130 ml of
dropwise was
99% pure
by glpc
of the product
NMR.
over
stirred
isolated
in the proton
in the fluorine
in dry
to 55O and l-bromo-3,3,3-
ice trap was was
funnel,
to two traps.
The round
the mixture
An aliquot
absorption
addition
chloride
was heated
with a heating
the second
with N2.
(0.4 mole)
was complete, From
and
gave
pressure
in ice water,
solution
of 3,3,3-trifluoropropene
CDC13
with
(53.1 g, 0.3
the addition
Poropak
a constant
16 g
MgS04,
layer
from l-Bromo-3,3,3-
2 g of benzyltrimethylammonium The stirred
After
was
then cooled
of the autoclave
flask was equipped
and a condenser
The first
bromide
bp 60-62'.
Preparation of 3,3,3-Trifluoropropene .___ trifluoropropane A 250 ml round
in dry
of hydrogen
organic
of the liquid
1-bromo-3,3,3-trifluoropropane
cooled
at 120' overnight,
dried
Distillation
(0.6 mole)
The contents
and vented.
50 ml H20,
38.4 g (0.3 mole)
The bomb was closed,
100 g of ice.
with
with
1 hr.
for an
26 g (90%) (4 ft x 1/8ft)
dissolved
in
NMR at 6 5.4-6.2
479
REFERENCES R. N. Haszeldine, M. Nager,
J. Chem.
J. Amer.
J. A. Valicenti, 3,739,036
Chem.
R. L. Halm,
I. Morioka,
(CA 82, 139,283f); (CA 60,
9148f);
(CA 79,
Japan
French
1,343,392
and R. K. Freidlina,
Otdel
Khim
Nauk,
Stowe
and R. A. Davis,
W. C. Smith,
Sot. 82,
L. s. German 349
(December
Patent
L. I.
Akad.
22343);
21, 1974)
15, 1963)
V. N. Kost,
(CA 54,
Y.
Nauk
S.S.S.R.,
R. P. Ruh,
2,889,379
R. A.
(June 2, 1959)
543
and V. A. Engelhardt,
J. Amer.
(1960).
and
I. L. Knunyantz,
Angew.
Chem.
and
I. L. Knunyantz,
Zh. Vses,
Inter.
Ed. g,
(1969).
L. s. German
von D. I. Mendeleeva P.
U.S.
H. Wada,
1295a).
W. R. Hasek, Chem.
(1960)
U.S. Patent
(November
Izvest.
and
(1951).
52775g);
74,133,308
A. N. Nesmeyanov,
447
(1953); A. L. Henne
F. 0. Stark,
Zakharkin,
(CA 54,
3371
Sot. 11, 1042
(June 12, 1973)
Hiramatsu,
Sot.
Tarrant,
Chem.
356
A. M. Lovelace,
Sot. 77, 2783
A. V. Podol'skii, Izv Akad.
11,
Nauk
(1966)
Obshchestva.
(CA 65, 15215h).
and M. R. Lilyquist,
J. Amer.
(1953).
L. S. German,
SSSR,
Khim.
Ser. Khim.
and I. L. Knunyantz, 1575
(1966)
(CA 66:95004d)