Organic compounds -- part of the class 532-570 series – Organic compounds – Phosphorus esters
Reexamination Certificate
2001-11-01
2003-03-18
Vollano, Jean F. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Phosphorus esters
C502S162000
Reexamination Certificate
active
06534669
ABSTRACT:
The present invention relates to a process for preparing alkenylphosphonic acid derivatives by reacting phosphonic acid derivatives with alkynes in the presence of a metal complex catalyst system.
Vinylphosphonic acid derivatives, in particular dialkyl vinylphosphonates are important as intermediates for the preparation of vinylphosphonic acids and as monomers for copolymerizations for producing adhesives and flame-resistant plastics.
Various methods are known for preparing them. The process described in DE-A 21 32 962 starts from ethylene oxide and phosphorus trichloride. The initial reaction product tris(2-chloroethyl) phosphite is rearranged at from 140 to 200° C. to form bis(2-chloroethyl) 2-chloroethanephosphonate and is then reacted with phosgene in the presence of a catalyst to form 2-chloroethanephosphonyl dichloride and vinylphosphonyl dichloride. Catalysts used are amines, heterocyclic nitrogen compounds, phosphines and also phosphine oxides.
EP 0 032 663 A2 describes a process for preparing vinylphosphonic acid derivatives in which dialkyl 2-acetoxyethanephosphonates are dissociated in the presence of acidic or basic catalysts. Basic catalysts proposed are tertiary amines and phosphines, ammonium salts or phosphonium salts, heterocyclic compounds and acid amides. A disadvantage of the process is the formation of a mixture of vinylphosphonic acid derivatives. The proportion of dialkyl vinylphosphonates is 23% at most.
An improved variant of this process described in DE 31 20 437 A1 comprises reacting the resulting product mixture with orthoesters of carboxylic acids to form dialkyl vinylphosphonates.
Disadvantages of the above processes are the formation of product mixtures, complicated multistage synthetic routes, the necessity of using high reaction temperatures and the use of chlorinated starting compounds. The large proportion of by-products, in particular, considerably impairs the process economics.
A further synthetic route for preparing diesters of alkenylphosphonic acids is the addition of alkynes onto diesters of phosphonic acid in the presence of a palladium complex catalyst. An advantage of this synthetic route is a pure addition reaction without formation of stoichiometric amounts of by-products or coproducts. U.S. Pat. No. 5,693,826 and WO 98/46613 disclose the addition in the presence of a palladium complex catalyst using phosphines and phosphites as ligands at temperatures less than or equal to 100°C. Wo 99/67259 and U.S. Pat. No. 6,111,127 specify bidentate phosphines as ligands. A disadvantage of these processes is the use of expensive noble metal catalysts.
U.S. Pat. No. 3,673,285 describes the addition of alkynes onto diesters of phosphonic acid to form diesters of alkenylphosphonic acids at from 130 to 200° C. in the presence of nickel complex catalysts selected from the group consisting of dicarbonylbis(triphenylphosphine)nickel(0), bis(tris(hydroxymethyl)phosphine)nickel(II) chloride, bis(tri-n-butylphosphine)nickel(II) bromide and tetracarbonylnickel(0). In the addition of ethyne onto diethyl phosphite, a yield of 40% of diethyl vinylphosphonate was achieved in the presence of bis(tri-n-butylphosphine)nickel(II) J bromide (Example 15). Disadvantages of this process are the low yield of significantly under 50% and the high reaction temperature of up to 200° C. required, which leads to exothermic decomposition of the ethyl phosphonate.
It is an object of the present invention to find a process for preparing alkenylphosphonic acid derivatives which does not have the abovementioned disadvantages, does not form any coproducts, allows a reaction temperature of significantly below 200° C., makes possible a high yield of significantly above 50% and makes do without use of an expensive noble metal catalyst.
We have found that this object is achieved by a process for preparing alkenylphosphonic acid derivatives by reacting phosphonic acid derivatives with alkynes in the presence of a metal complex catalyst system comprising
a) nickel and
b) a phosphine having at least two trivalent phosphorus atoms.
An essential feature of the process of the present invention is the presence of a metal complex catalyst system comprising (a) nickel and (b) a phosphine having at least two trivalent phosphorus atoms. Phosphines having two trivalent phosphorus atoms are generally referred to as diphosphines, phosphines having three trivalent phosphorus atoms are generally referred to as triphosphines, and so forth.
In general, the phosphines used in the process of the present invention have the formula (I)
where R
1
, R
2
, R
3
and R
4
are each, independently of one another, a carbon-containing organic radical and X is a carbon-containing organic bridging group.
For the purposes of the present invention, a carbon-containing organic radical is an unsubstituted or substituted, aliphatic, aromatic or araliphatic radical having from 1 to 30 carbon atoms. This radical may contain one or more hetero atoms such as oxygen, nitrogen, sulfur or phosphorus, for example —O—, —S—, —NR—, —CO—, —N═, —PR— and/or —PR
2
, and/or be substituted by one or more functional groups containing, for example, oxygen, nitrogen, sulfur and/or halogen, for example by fluorine, chlorine, bromine, iodine and/or a cyano group (the radical R here is likewise a carbon-containing organic radical). If the carbon-containing organic radical contains one or more hetero atoms, it may also be bound via a hetero atom. Thus, for example, ether, thioether and tertiary amino groups are also included. The carbon-containing organic radical can be a monovalent or polyvalent, for example divalent, radical.
For the purposes of the present invention, a carbon-containing organic bridging group is an unsubstituted or substituted, aliphatic, aromatic or araliphatic divalent group having from 1 to 20 carbon atoms and from 1 to 10 atoms in the chain. The organic bridging group may contain one or more hetero atoms such as oxygen, nitrogen, sulfur or phosphorus, for example —O—, —S—, —NR—, —CO—, —N═, —PR— and/or —PR
2
, and/or be substituted by one or more functional groups containing, for example, oxygen, nitrogen, sulfur and/or halogen, for example by fluorine, chlorine, bromine, iodine and/or a cyano group (the radical R here is likewise a carbon-containing organic radical). If the organic bridging group contains one or more hetero atoms, it may also be bound via a hetero atom. Thus, for example, ether, thioether and tertiary amino groups are also included.
In the process of the present invention, preference is given to using a phosphine (I) in which the radicals R
1
, R
2
, R
3
and R
4
are each, independently of one another,
an unbranched or branched, acyclic or cyclic, unsubstituted or substituted alkyl radical having from 1 to 20 aliphatic carbon atoms, in which one or more of the CH
2
groups may also be replaced by hetero atoms such as —O— or by hetero atom-containing groups such as —CO— or —NR—, and in which one or more of the hydrogen atoms may be replaced by substituents such as aryl groups;
an unsubstituted or substituted aromatic radical having one ring or two or three fused rings, in which one or more ring atoms may be replaced by hetero atoms such as nitrogen, and in which one or more of the hydrogen atoms may be replaced by substituents such as alkyl or aryl groups;
or in which the radicals R
1
together with R
2
and/or R
3
together with R
4
form
an unsubstituted or substituted, aliphatic, aromatic or araliphatic group having from 3 to 10 atoms in the chain.
Examples of preferred monovalent radicals R
1
, R
2
, R
3
and R
4
are methyl, ethyl, 1-propyl, 2-propyl (sec-propyl), 1-butyl, 2-butyl (sec-butyl), 2-methyl-1-propyl (isobutyl), 2-methyl-2-propyl (tert-butyl), 1-pentyl, 2-pentyl, 3-pentyl, 2-methyl-2-butyl (tert-amyl), 1-hexyl, 2-hexyl, 3-hexyl, 2-methyl-2-pentyl, 3-methyl-3-pentyl, 2-methoxy-2-propyl, methoxy, ethoxy, 1-propoxy, 2-propoxy (sec-propoxy), 1-butoxy, 2-butoxy (sec-butoxy), 2-methyl-1-propoxy (isobutoxy), 2-methyl-2-propoxy (tert-butoxy), 1-pentoxy, 2-pentoxy, 3-pentoxy, 2-methyl
Arndt Jan-Dirk
Henkelmann Jochem
Klass Katrin
BASF - Aktiengesellschaft
Keil & Weinkauf
Vollano Jean F.
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