Fluorination of Hydrogen-containing with elemental fluorine

Journal of Fluorine Chemistry, 38 (1988) Received:

March

FLUORINATION

25, 1987; accepted:

Industrial

December

OF HYDROGEN-CONTAINING

L. CONTE, G.P. GAMBARETTO*, Chemistry

319

319-326 7, 1987

OLEFINS

WITH

ELEMENTAL

FLUORINE

M. NAPOLI

Institute,

Via Marzolo

9, 35131 Padua (Italy)

C. GERVASUTTI MONTEFLUOS

S.p.A.,

Laboratorio

Fluoroderivati,

P. Marghera

(Italy)

SUMMARY

The hydrohalo-olefins and CH2=CCl-CH2Cl yields

cis and trans CHCl=CHCl,

have been fluorinated

of hydrohalofluoroalkanes.

addition

to the double

substitution,

have been studied.

with elemental

The best operational

bond rather than hydrogen

dimerization

and oligomerization

Preliminary

Freon 22 towards elemental

CHCl=CC12,

fluorine

to give good

conditions

and/or chlorine

of radical

studies on the reaction

fluorine

CHCl=CH-CH2Cl

for F2 atom

intermediates

of Freon 12 and

have also been carried

out.

INTRODUCTION

Although reported

the addition

n,2,33

the published

halogen-containing fluorine

olefins.

and olefins

In these works substitution

@,5,d

reaction

139/88/$3.50

to double bonds has been extensively

research

Only limited

containing

hydrogen

however

is concerned

almost exclusively

studies deal with reactions

with

of

atoms.

the conditions

and the addition

occurs with only extremely

0022-l

of fluorine

are favorable

of fluorine

to the

to the double bond

low yields.

0 Elsevier

Sequoia/Printed

in The Netherlands

320

RESULTS AND DISCUSSION

A preliminary has been carried substitution

study on the reaction

out to find the best reaction

reaction

of hydrogen

12 reacts with fluorine percentage

of Freon 12 and Freon 2.2 with fluorine

diluted

conditions

and/or chlorine.

to minimize

At room temperature

up to 10% in nitrogen

substitution

with increasing

reaction

concentration

of chlorine

Freon

only in a very small

(about 2-3%) to give Freon 13. Below 0 "C no reaction

room temperature

the

of fluorine

occurs. At

in nitrogen,

atoms in Freon 12 becomes

the

increasingly

important. With Freon 22 we have noticed, atom reacts with fluorine The products

formed

as already

and in some cases the reaction

by the reaction

to verify which operating

and limit the substitution reaction carried

occurs,

controlled nitrogen

or it is negligible,

by changing

occurs explosively.

has been closely

to choose

are reported

It is evident

in order to control

under which the substitutil in Table 1, for tests

that the reaction

of fluorine

can be

and Freon in the

mixture. of Freon 22 higher than 8 % the substitution

occurs at all concentrations than 7 % the reaction

of fluorine,

soon as the reagents is started,

of fluorine

in nitrogen

substitution

of hydrogen

occurs

the reactor.

way forming

is bubbled

reactions

temperature

through

Freon 13 and Freon 14.

into Freon 22 at -80 "C, the

the hydrogen

the concentration

was established,

as

Once the reaction

to a limited extent when working

of controlling

lower

higher than

with a high

of fluorine.

Once the possibility substitution

concentrations

takes place immediately,

mix in the space preceding

a mixture

concentration

reaction

it goes on in an uncontrollable

reaction

while with Freon percentages

occurs only with fluorine

14 %. In some cases the substitution

reaction

fluorine

The conditions

the concentration

With concentrations

If

towards

parameters

reaction.

out at room temperature.

that the hydrogen

are Freon 13 and Freon 14.

The study of Freon 22 reactivity examined

foreseen,

and/or chlorine

of reactants

and the

the research was focussed

on some

321

TABLE

1

Reaction of fluorine on F22

(CHCIF2)

Fluorine (% in N2)

CHClF2 (% in

6

a

10

11

N

Reaction

2'

5.5

NO

8.5

YES

6.0

NO

11.3

YES

7.3

NO

13.0

YES

6.6

NO

a.4

14

20

hydrohalo-olefins, dichloroethylene,

under our working

6.6

NO

9.3

YES

6.3

YES

10.1

YES

and particularly 1,3-dichloropropene

was fed in Freon 11 as solvent, conditions.

YES

on trichloroethylene,

&-

and 2,3-dichloropropene.

and transThe olefin

since it proved to be inert to fluorine

The conditions

and the product yields

are

322

given in Table 2. It is observed

(tests 1 and 3) that for dichloroethylene

the cis isomer is more reactive,

while the trans one is more selective.

In fact for the same amount of fed fluorine greater

the olefin conversion

for the cis isomer, while the yield of the addition

on the reacted

is greater

olefin,

tests of Table 2, the composition 3. The quantity

of substitution

is

product,

based

for the trans isomer. For the first three of the reaction mixture

products

is given in Table

and of the dimer is

higher for

the cis dichloroethylene. From test 2 it is clear that an increase nitrogen

causes a decreased

increase

in substitution

mostly

in an increase

reactor.

fluorine

products

with lowered

atoms

present

mixture

product

boiling

Table 4 gives the identified

and a relative

reactions,

These products

products

in

but

in the outlet gasses from the

point because

by the nitrogen

percentage

in the reaction mixture,

of the substitution

in the molecule.

from the reaction

of addition

of the same products

As a consequence

of products

yield

of fluorine

there is formation

of an increased are therefore

stream that dilutes

in the reaction mixture

number of

stripped the fluorine. and in the

outlet gasses. In regard to the temperature at -59 "C

there is a noticeable

and an increase

in the percentage

For trichloroethylene

effect

decrease

and dimerization

with fluorine

The addition products

been noticed

in the yield of addition

of substitution

the reactivity

the one of cis dichloroethylene.

it has already

product

of chlorine

that product products.

is comparable

with

to double bond,

together

with the substitution

obtained

in relatively

good yields.

chlorine

substitution,

such as Freon 113, Freon 114 and Freon 123, were

Products

and hydrogen,

formed by hydrogen

are

and/or

identified. For dichloropropenes

studied

in the tests 6, 7, 8 and 9, the best yields

have been obtained

with 1,3-dichloropropene,

propenes

Together

examined.

with the addition

double bond, the other main compound from the substitution

of the hydrogen

obtained

the less polar of the two product of fluorine

to the

is CHClF-CF2-CH2C1,

formed

atom in position

two. In the case of

Solution

14.2

9) CHCl-CH-CH2Cl

-70°C

-70°C

6.33 1.5

55.5%

0.25

6

+ olefin "as added after 4 hours

B-based on c&fin reacted

-72'C

-73'C

-75°C

-59'C

-75'C

-75'C

-75°C

6.38

6.6

6.38

5.63

7.12

4.89

Reaction Temp. 'C

2.5

1.5

2.5

7

6

7.5

8'

8

Rate of F2 addn. g/hr

93%

57.7%

93%

76.7%

61%

42.72

66%

45.4%

Reaction Time hr.

0.42

0.26

0.42

0.87

0.89

0.97

1.5

1.03

Flll0rifle F flowed 2 (mole) F2 theor.

1

6

1.2

2.45

2.67

12.32

7.55

8.5%

A-based on total amount of fluorine added

14.2

14.2

14.2

12.7

12.0

12.82

12.82

12.82

Starting Final

%Olefin in

8) CHWH-CH2Cl

7) CH2=CCl-CH2Cl

6) CH~=CC~-CH~CI

5) CHCl=CC12

cis

4) CHCl=CHCl

3) CHCl=CHCl t trans

tr.Bns+

2) CHCl=CHCl

cis+

1) CHCl=CHCl

TABLE 2

26%

42%

47%

1O:l

1O:l

28%

45%

30%

54%

49%

54%

Yield of addition product A

1O:l

1O:l

13:l

12:l

13:l

9:l

13:l

N2'F2

Molar ratio

59%

93.2% 42.5%

44%

59%

91%

81%

78%

32%

56%

53%

25.6%

29.5%

41.5%

58%

46%

Slefin 'ieldof addition Conversion roduct R

324

TABLE 3

Composition

of reaction

products

run 1 CHCl=CHCl cis

CHF2-CF2C1

CHClF-CHF

2

run 3 CHCl=CHCl trans

run 2 CHCl=CHCl trans

0.37%

/

/

5.14%

4.56%

3.61%

CHClF-CHClF

70.2%

69.6%

73.0%

Dimer

20.0%

13.5%

13.7%

4.3%

11.8%

9.6%

Other

Products

TABLE 4

Identified

Products Solution

b.p.

F124a

CHF2-CF2C1

-10.2Oc

F114

CF2Cl-CF2Cl

F133

CHF2-CHFCl

17.0°c

F123a

CHFCl-CF2C1

28.2"C

F132

CHFCl-CHFCl

59.0°c

3.6'C

Gas Outlet F125

CF3-CHF

-48.5'C

F115

2 CF3-CF2C1

F134

CHF2-CHF2

-19.7OC

F124

CHF2-CF2C1

-10.2"c

F133

CHF,-CHFCl

17.0°c

-38.7'C

325

2,3-dichloropropene,

the substitution

three and CH2F-CClF-CHClF of products CHCl=CH-CHF2

such as CH2=CC1-CHClF, was also observed.

rise from substitution Moreover further

CH2=CC1-CHF2,

and/or from cracking

and the use of catalysts

retaining

and/or chlorine

data are in accordance

in position

CHCl=CH-CHClF

These compounds

of hydrogen

atom occurs

In the reaction mixture the presence

the whole series of the products

substitution

experimental

is formed.

of hydrogen

and

the double

in position

resulting

bond

3.

from reactions

has been observed.

with a free radical

of

The available

reaction

mechanism

such as SbC13 and SbC15 do not have any effect.

CONCLUSIONS

The tests carried

out allowed

us to verify that it is possible

fluorine

to the double bond of hydrohalo-olefins

addition

products.

dimerization would

The competitive

substitution

can be limited by controlling

point out the importance

in the nitrogen

the final composition

working

with an olefin concentration

We

concentration

in the reaction We suggest

15% and to keep the

at a fixed value as long as the test runs with a continuous

of fresh olefin.

so as to ensure important

as well as the

and fluorine

of the products.

of about

for the

conditions.

flow as well as of olefin concentration

as affects

feeding

reactions

the reaction

of temperature

mixture

concentration

with good yields

to add

Stirring

of the reaction

good heat transfer.

is important

It has been found that the most

factor for the selectivity

and it seems that working

mixture

of the reaction

at a temperature

is the temperature

lower than -70 "C is important.

EXPERIMENTAL

Two kinds of reactor

have been used according

which the reactivity

with fluorine

When the experiments

were carried

boiling

point of the compound

diluted

in nitrogen

of various

to the temperature

compounds

out at a temperature

to be tested,

at

was to be studied. higher than the

this was mixed with fluorine

and fed into a 500 ml copper tubular

reactor fitted

326

with copper chips. The reactor which a thermostatic

fluid was circulating.

the reactor was measured For the reaction of the compound bubbled

had an external

carried

out at temperatures

to be experimented

reactor

with an immersion was equipped

The internal

jacket

inside

temperature

of

with a thermocouple.

the fluorine

into the liquid or into the mixture

cylindrical

thermostatic

below the boiling diluted

in nitrogen

of Freon and olefin

held in a dewar containing

trichloroethylene

point was

in a cooled

cooler. The 1000 ml reactor, made of teflon or glass,

with a paddle stirrer.

The GLC determinations Chromatograph

were carried

using He as a carrier

out with a Shimadzu

gas and a copper column

GC-8APT (4 mm x 6 mt)

packed with OS ZOO/50 on Chromosorb. The identification Perkin-Elmer

of the reaction

products

was carried

out with a ITD

Mass Spectrometer.

ACKNOWLEDGEMENT

This work has had the financial

support

from Montefluos

S.p.A., Milano.

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J.D. Stoffer,

J. Am. Chem. Sot., 78 (1956) 4992

G. Fuller and A.C. Currie, J. Am. Chem. Sot., @

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J. Chem. Sot., 62 (1940) 341.

5 R. Foon and G.P. Reid, J. Phys. Chem., z 6 G.A. Kapralova, SSSR, 150

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