Process for the manufacture of halocarbons

Details Process for the manufacture of halocarbons Process for the manufacture of halocarbons

1999-07-13

2001-07-03

Higel, Floyd D. (Department: 1626)

Organic compounds -- part of the class 532-570 series

Organic compounds

Halogen containing

C570S247000, C570S261000

Reexamination Certificate

active

06255544

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a process for the manufacture of halogenated alkanes using the catalytic reaction of haloalkanes with halogenated olefins.
BACKGROUND
The catalyzed radical addition of haloalkanes to olefins is a well known reaction. Typically, however, when a haloalkane (e.g., AB, where A is a substituted carbon atom and B is a halogen other than fluorine) is added to an olefin (e.g., CH
2
═CHR) to form the saturated adduct (e.g., CH
2
ACHBR), the products (i.e., halogenated addition compounds) also include varying amounts of telomers (e.g., A(CH
2
CHR)
n
B, where n is equal to 2 or more). For example, Canadian Patent No. 2,073,533 discloses a process for the manufacture of CCl
3
CH
2
CCl
3
by reacting carbon tetrachloride with vinylidene chloride using copper catalysts in acetonitrile. The selectivity for CCl
3
CH
2
CCl
3
with respect to converted vinylidene chloride was 87%. It has been shown in the art that the major by-product is the C
5
telomer, CCl
3
(CH
2
CCl
2
)
2
Cl. Furthermore, since the catalyzed addition of haloalkanes to olefins is done in a homogeneous medium, separation of the catalyst from the product can present difficulties. This is especially so when it is desired to run the reaction in a continuous manner.
The halogenated adducts are useful intermediates for the production of fluoroalkanes, particularly, hydrofluoroalkanes. These latter compounds are useful as refrigerants, fire extinguishants, heat transfer media, propellants, foaming agents, gaseous dielectrics, sterilant carriers, polymerization media, particulate removal fluids, carrier fluids, buffing abrasive agents, displacement drying agents and power cycle working fluids. There is an interest in developing more efficient processes for the manufacture of hydrofluoroalkanes.
SUMMARY OF THE INVENTION
A liquid phase process is provided in accordance with this invention for producing halogenated alkane adducts of the formula CAR
1
R
2
CBR
3
R
4
wherein R
1
, R
2
, R
3
, and R
4
are each independently selected from the group consisting of H, Br, Cl, F, C
1
-C
6
alkyl, CN, CO
2
CH
3
, CH
2
Cl, and aryl (e.g., phenyl), provided that when either R
3
or R
4
is selected from the group consisting of C
3
-C
6
alkyl, CN, CO
2
CH
3
, CH
2
Cl, and aryl, then R
1
, R
2
, and the other of R
3
and R
4
are H, and when R
3
and R
4
are selected from the group consisting of Cl, F, CH
3
and C
2
H
5
, then R
1
and R
2
are H, and when either R
1
or R
2
and either R
3
or R
4
are selected from the group consisting of Cl, F, CH
3
and C
2
H
5
, then the other of R
1
and R
2
and the other of R
3
and R
4
are H; A is selected from the group consisting of CX
3
, CH
3−a
X
a
, C
n
H
(2n+1)−b
X
b
and CH
c
X
2−c
R, where R is C
n
H
(2n+1)−b
X
b
(e.g., CF
3
and CCl
2
CF
3
), each X is independently selected from the group consisting of Br, F, Cl and I, a is an integer from 0 to 3, n is an integer from 1 to 6, b is an integer from 1 to 2n+1, and c is an integer from 0 to 1; and B is selected from the group consisting of Br, Cl and I; provided that (1) when A is CX
3
then only one of X is I, (2) when A is CH
3−a
X
a
, then each X is B and a is 2 when B is Br or Cl, and a is an integer from 0 to 2 when B is I, and (3) when A is CnH
(2n+1)−b
X
b
, then each X is independently selected from Cl and F, and B is I. The process comprises contacting a halogenated alkane of the formula AB (where A and B are as indicated above) with an olefin of the formula CR
1
R
2
═CR
3
R
4
(where R
1
, R
2
, R
3
and R
4
are as indicated above) in a dinitrile or cyclic carbonate ester solvent which divides the reaction mixture into two liquid phases and in the presence of a catalyst system containing (i) at least one catalyst comprising monovalent copper; (ii) at least one ionic promoter selected from the group consisting of substituted ammonium halides, pyridinium and substituted pyridinium halides, and quaternary salts of the type (MQ
4
)Y where M is an element of Group VA of the Periodic Table (i.e., N, P, As, Sb, or Bi), Q is a C
1
-C
18
hydrocarbyl group, and Y is Cl, Br or I; and optionally (iii) a non-ionic promoter selected from the group consisting of aromatic or aliphatic non-ionic heterocyclic compounds which contain at least one carbon-nitrogen double bond in the heterocyclic ring.
This invention further provides a process for producing hydrofluoroalkanes (e.g., CF
3
CH
2
CHF
2
). This process comprises (a) producing a halogenated alkane adduct (e.g., CCl
3
CH
2
CHCl
2
) by reacting AB (e.g., CCl
4
) and CR
1
R
2
═CR
3
R
4
(e.g., CH
2
═CHCl) as indicated above (provided that R
1
, R
2
, R
3
and R
4
are independently selected from H, CH
3
, C
2
H
5
, C and F, B and X are Cl and at least one of AB and CR
1
R
2
═CR
3
R
4
contains hydrogen), and (b) reacting the adduct produced in (a) with HFP.
DETAILED DESCRIPTION
The present invention relates to the addition of halogenated alkanes to unsaturated compounds to form an adduct. Specifically, this invention relates to the addition of a halogenated alkane of the general formula AB to an unsaturated compound CR
1
R
2
═CR
3
R
4
to form a corresponding adduct CAR
1
R
2
CBR
3
R
4
in a the presence of a monovalent copper catalyst (Cu
+
) in a suitable solvent (a dinitrile or cyclic carbonate ester solvent). An ionic promoter is used to enhance the reaction. A second, non-ionic promoter containing a C═N ring bond may also be advantageously used.
The addition of saturated, halogenated alkanes to alkenes to form adducts is known in the art. A wide range of saturated, halogenated alkanes may be used in the process of the invention. Examples of suitable saturated, halogenated alkanes are given by Walling and Huyser in Tables V, VI, VII, and VIII in Chapter 3 of Organic Reactions, Vol. 13 (1963).
Halogenated alkanes, AB, that are particularly useful for the process of this invention include certain compounds where A is selected from the group consisting of CX
3
, CH
3−a
X
a
, C
n
H
(2n+1)−b
X
b
and CH
c
X
2−c
R where each X is Br, F, Cl or I and R is C
n
H
(2n+1)−b
X
b
(e.g., CF
3
and CCl
2
CF
3
); and B is Br, Cl or I. Included are compounds where A is CX
3
and only one of X is I. Also included are compounds where A is CH
3−a
X
a
where X is B and where when X is Br or Cl, a is 2, and when X is I, a is an integer from 0 to 2. Also included are the compounds where A is C
n
H
(2n+1)−b
X
b
, where each X is independently selected from Cl and F, n is an integer from 1 to 6, b is an integer from 1 to 2n+1, and B is I. Also included are compounds where A is CH
c
X
2−c
R wherein c is an integer from 0 to 1. Examples of saturated, halogenated alkanes suitable for the process of this invention include CCl
4
, CBrCl
3
, CCl
2
FCCl
2
F, CCl
3
CClF
2
, CCl
3
CF
3
, CCl
3
CF
2
CCl
3
, CCl
3
CF
2
CF
3
, CCl
3
CH
2
CCl
3
, CCl
3
CH
2
CF
3
, CCl
3
CF
2
CClF
2
, CF
3
I, CF
3
CF
2
I, CF
3
CFICF
3
and CF
3
CF
2
CF
2
I.
A wide range of alkenes may be used in the process of the invention. Examples of suitable alkenes are given by Walling and Huyser in Tables V, VI, VII, and VIII in Chapter 3 of Organic Reactions, Vol. 13 (1963). Examples of alkenes suitable for the process of this invention include CH
2
═CH
2
, CH
2
═CHCl, CH
2
═CHF, CHCl═CHCl, CH
2
═CCl
2
, CH
2
═CF
2
, CH
2
═CHCH
3
, CH
2
═CHCH
2
Cl, and CH
2
═CHC
6
H
5
.
The addition of halogenated alkanes to alkenes to form the corresponding adducts is catalyzed by copper(I) compounds, that is, copper compounds in the +1 oxidation state. Preferred copper compounds for the process of this invention include copper(I) chloride, copper(I) bromide, copper(I) iodide, copper(I) acetate, and copper(I) thiocyanate. Especially preferred copper compounds for the process of this invention include copper(I) chloride and copper(I) bromide. The catalysts are preferably anhydrous; and preferably, the addition of halogen

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