Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Phosphorus or compound containing same
Reexamination Certificate
2000-07-17
2002-06-18
Rotman, Alan L. (Department: 1625)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Phosphorus or compound containing same
59, 59, C546S345000, C558S424000, C568S433000, C568S437000, C570S147000
Reexamination Certificate
active
06407029
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to mixtures comprising aminophosphonium salts (mixtures of substances), and to the preparation and use thereof.
Aminophosphonium compounds are used, as is evident from WO 98/32532 and WO 98/22413, as catalysts in the preparation of fluorine-containing compounds by a halogen-fluorine exchange reaction (halex reaction). Although the tetrakis(diethylamino)phosphonium bromide used in WO 98/32532 and WO 98/22413 gives good results, it has a very high dermal toxicity. The very high dermal toxicity of <50 mg/kg body weight stands in the way of industrial use, however.
SUMMARY OF THE INVENTION
The object is to provide novel mixtures which comprise high proportions of tetrakisaminophosphonium salts and which are suitable as catalysts or constituent of catalyst systems for phase-transfer reactions, in particular for halogen-fluorine exchange reactions, have a lower dermal toxicity and reach or even exceed the results which can be achieved on use of tetrakis(diethylamino)phosphonium bromide. It is additionally intended that preparation of these mixtures even in industrial quantities be possible in a comparatively simple manner at reasonable expense.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
This object is surprisingly achieved by mixtures comprising from 70 to 99.5% by weight of a compound of the formula (R)
4
P
+
X
−
(1) and from 30 to 0.5% by weight of a compound of the formula (R)
3
P═O (2), where R is in each case a radical
and X
−
is an inorganic or organic anion or the equivalent of a multiply charged inorganic or organic anion.
The mixtures comprise high proportions of the compounds of the formula (R)
4
P
+
X
−
(1), namely the appropriate tetrakis(pyrrolidino)phosphonium salts or the tetrakis(piperidino)phosphonium salts. The compounds (R)
3
P═O present in the mixture surprisingly have no adverse effects on the catalytic activity so that the mixtures can be employed directly as catalyst or catalyst component.
The dermal toxicity both for tetrakis(pyrrolidino)phosphonium chloride and for tetrakis(piperidino)phosphonium chloride is unexpectedly significantly less than that of tetrakis(diethylamino)phosphonium bromide, although there are no pronounced differences in relation to the molecular structure/molecular size and molecular mass of the tetrakisphosphonium cation. The dermal toxicity of tetrakis(piperidino)phosphonium chloride is ~200 mg/kg body weight, that of tetrakis(pyrrolidino)phosphonium chloride is ~390 mg/kg body weight, and is thus considerably less than that of tetrakis(diethylamino)phosphonium bromide. The data for the dermal toxicities of tetrakis(diethylamino)phosphonium bromide, tetrakis(piperidino)phosphonium chloride and tetrakis(pyrrolidino)phosphonium chloride are derived from our own measurements.
The present invention relates in particular to mixtures comprising 75 to 99, preferably 80 to 98, particularly preferably 85 to 95, % by weight of the compound (R)
4
P
+
X
−
(1) and 25 to 1, preferably 20 to 2, particularly preferably 15 to 5, % by weight of the compound (R)
3
P═O (2). R is—as already stated previously—both in the compounds (1) and in the compounds (2) a pyrrolidino or piperidino radical, in particular a pyrrolidino radical.
X
−
in the compounds of the formula (1) is F
−
, Cl
31
, Br
−
, I
−
, ClO
4
−
, BF
4
—, PF
6
−
, NO
3
−
, HSO
4
−
, ½ SO
4
2−
, H
2
PO
4
−
, ½ HPO
4
2−
, ⅓ PO
4
3−
, R″—COO, where R″ is an alkyl radical having 1 to 9 carbon atoms, a phenyl radical, benzyl radical or naphthyl radical, R′″—SO
3
−
, where R′″ is an alkyl radical having 1 to 18 carbon atoms, a phenyl radical, tolyl radical or naphthyl radical, HCO
3
−
, ½ CO
3
2−
or {fraction (
1
/
2
)} C
6
H
4
(COO
−
)
2
. X
−
is, in particular, F
−
, Cl
−
, Br
−
, I
−
, BF
4
−
, PF
6
−
or ½ SO
4
2−
, preferably F
−
, Cl
−
or Br
−
, particularly preferably Cl
−
.
The mixtures normally result as mixtures of substances consisting of 95 to 100, in particular 96 to 99.5, preferably 97 to 99, % by weight of the mixture comprising the compounds (R)
4
P
+
X
−
and (R)
3
P═O and 5 to 0, in particular 5 to 0.5, preferably 3 to 1, % by weight of volatile constituents. Volatile constituents which may still be present are, for example, residues of unreacted starting materials and solvents. However, it is possible to remove the volatile constituents very substantially or completely.
G. N. Koidan et al., describe in J. Gen. Chem. USSR (Engl. Transl.) 52, 1982, pages 1779 to 1787, a multistage preparation of tetrakis(piperidino)phosphonium bromide. This entails initial reaction of a compound of the formula (R
2
N)
3
P
+HalHal
−
with ammonia, and preparation from the reaction product which is formed, with elimination of water, of a triamide of an iminophosphoric acid (phosphorimidic triamide).
The triamide of the iminophosphoric acid is then converted with 1,5-dibromopentane in accordance with the following reaction equations
(R
2
N)
3
P═NH+Br(CH
2
)
5
Br→(R
2
N)
3
P═N—(CH
2
)
5
—Br 3.
by a ring-closure reaction into tetrakis(piperidino)phosphonium bromide.
This type of synthesis is very complicated, requires several reaction stages and leads to a reaction product which, besides the tetrakis(piperidino)phosphonium bromide, still contains strongly basic compounds of the formula (R
2
N)
3
P═NH and (R
2
N)
3
P═N—(CH
2
)
5
Br. These compounds interfere with the catalytic activity, in particular with the selectivity for particular halex reactions.
There is consequently a need to provide a process for preparing tetrakis(piperidino)phosphonium salts which avoids the aforementioned disadvantages, can be implemented even industrially in a straightforward manner and makes the required products available in good yields.
The object is achieved by a process for preparing the aforementioned mixtures comprising the compounds (R)
4
P
+
X
−
and (R)
3
P═O. It comprises reacting a phosphorus pentahalide with pyrrolidine or piperidine in the molar ratio 1:6 to 1:50 in the presence of an inert solvent, initially at 10 to 80° C., subsequently continuing the reaction at 90 to 180° C., treating the resulting reaction product at 0 to 80° C. with aqueous alkali at a pH of 7 to 15, and separating aqueous and organic phase from one another.
Normally pyrrolidine or piperidine is added to the mixture of phosphorus pentahalide and solvent, but the reverse procedure is also possible. The reaction moreover proceeds initially in the aforementioned temperature range. The temperature should ordinarily be kept in the stated temperature range, where appropriate by cooling. Care must be taken that the reactants are thoroughly mixed. This reaction step is particularly straightforward when pyrrolidine or piperidine is added at a rate such that said temperature range is maintained.
Following this reaction step the reaction is, as stated above, continued at a higher temperature, at which the required tetrakis(pyrrolidino)- or tetrakis-(piperidino)phosphonium salt is formed.
Long reaction times and high reaction temperatures favor the formation of the tetrakis(pyrrolidino)- or tetrakis(piperidino)phosphonium salts, whereas shorter reaction times and low reaction temperatures lead to mixtures with an increased proportion of (R)
3
P═O compounds.
After completion of this reaction, the reaction product is, as already mentioned above, treated at a temperature of from 0 to 80° C. with an aqueous alkali. The amount of alkali employed is such that a pH of 7 to 15 is maintained during the treatment. The treatment with the aqueous alkali leads to hydrolysis of hydrolyzable constituents of the reaction product. The compounds of the formula (R)
3
P═O (2) presumably result from this hydrolysis and may b
Beck Andreas
Hahn Walter
Pfirmann Ralf
Schiemenz Berthold
Wessel Thomas
Clariant GmbH
Covington Raymond
Hanf Scott E.
Rotman Alan L.
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