Organic compounds -- part of the class 532-570 series – Organic compounds – Halogen containing
Reexamination Certificate
1999-11-03
2002-06-04
Padmanabhan, Sreeni (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Halogen containing
C570S257000
Reexamination Certificate
active
06399839
ABSTRACT:
The present invention relates to a process for the preparation of halohydrocarbons comprising at least 3 carbon atoms, by catalytic reaction between a halo-alkane and an olefin.
The addition of a haloalkane to an olefin is a well-known reaction. However, it is sometimes difficult to control the reaction such that a single olefin molecule adds to a haloalkane molecule (formation of a 1:1 adduct or addition product).
Very often, copper derivatives are used to catalyse this addition reaction. For example, M. Asscher and D. Vofsi (J. Chem. Soc. 1887-1896, 1963) describe the addition of carbon tetrachloride to olefins in the presence of catalysts containing copper or iron. However, this process has the drawback of requiring long periods of heating in order to obtain the addition product in an acceptable yield.
Patent application WO 97/07083 describes a process for the preparation of halohydrocarbons under the catalytic action of cuprous chloride in the presence of t-butylamine as cocatalyst. In such a process, the yield of telomerization product is still fairly low.
The invention is thus directed towards providing a process which makes it possible to gain access, in excellent yield, to halohydrocarbons comprising at least 3 carbon atoms, in a single step and starting with readily available reagents.
Consequently, the present invention relates to the preparation of halohydrocarbons comprising at least 3 carbon atoms, by reaction between a haloalkane and an olefin in the presence of
(a) an organocopper compound as catalyst; and
(b) a polar solvent and/or a cocatalyst chosen from amines, amides and trialkylphosphine oxides.
The organocopper compound used as catalyst in the process according to the present invention is preferably a compound formed with an organic acid compound. Carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, acetylacetic acid, cyclo-hexanebutyric acid and benzoic acid typically constitute organic acid compounds. Chloro- or fluorocarboxylic acids, such as trichloroacetic acid and trifluoroacetic acid, are also suitable. Sulphonic acids, sulphinic acids and phosphonic acids, as well as chloro or fluoro derivatives thereof, may also be suitable. Other organic acid compounds are compounds having a hydrogen atom close to one or more electron-withdrawing groups such as carbonyl (C═O), nitrile (CN), sulphone (SO
2
R), nitro (NO
2
) and phenyl groups, as well as chloro or fluoro derivatives thereof. Among the organic acid compounds according to this definition, mention may be made in particular of acetylacetone, trifluoroacetylacetone, 1,1,1,5,5,5-hexa-fluoropentane-2, 4-dione, acetonitrile, ethyl aceto-acetate, nitromethane, diphenylmethane, phenol and dimethyl sulphone. Copper compounds formed with organic acid compounds such as those mentioned above can be used in the process according to the present invention. The copper compounds formed with compounds such as acetylacetone, ethyl acetoacetate, acetic acid or cyclohexanebutyric acid and the chloro and fluoro derivatives thereof, are preferred. Copper (II) compounds are particularly preferred. Advantageously, the catalyst in the process according to the present invention is chosen from copper (II) acetate, copper (II) cyclohexanebutyrate and copper (II) acetylacetonate. Preference is most particularly given to the compound formed between copper (II) and acetylacetone (copper (II) acetylacetonate, abbreviated as Cu(acac)
2
) as catalyst in the process according to the present invention.
In a first embodiment of the process according to the invention, the reaction is carried out in the presence of a solvent. Any solvent in which the reagents form the desired product in satisfactory yield can be used. Advantageously, the reaction solvent is an alcohol, a nitrile, an amide, a lactone, a trialkylphosphine oxide or another polar solvent. Oxygen-containing solvents (i.e. solvents in which the molecule contains at least one oxygen atom) are preferred.
Among the alcohols which can be used as reaction solvent are, in particular, methanol, ethanol, isopropanol and tert-butanol. Among the nitrites which can be used as reaction solvent are, in particular, aliphatic nitriles, in particular acetonitrile, propio-nitrile or adiponitrile, and aromatic nitriles, in particular benzonitrile or tolunitrile. Among the nitriles, propionitrile and adiponitrile are preferred. Among the amides which can be used as reaction solvent are linear amides such as N,N-dimethylacetamide and N,N-dimethylformamide, and cyclic amides such as N-methylpyrrolidone. Mention may also be made of hexa-methylphosphoramide. Among the lactones which can be used as reaction solvent, mention may be made in particular of &ggr;-butyrolactone. Among the trialkylphosphine oxides which can be used as reaction solvent, mention may be made in particular of the compounds of formula (R
1
R
2
R
3
)PO, in which R
1
, R
2
and R
3
represent identical or different, preferably linear C3-C10 alkyl groups. Tri (n-butyl)-phosphine oxide, tri(n-hexyl)phosphine oxide, tri(n-octyl)phosphine oxide, n-octyldi(n-hexyl)phosphine oxide and n-hexyldi(n-octyl)phosphine oxide and mixtures thereof are selected in particular. As other polar solvents, mention may also be made of 1,3-dimethyl-2-imidazolidinone, dimethyl sulphoxide and tetrahydrofuran. Preferably, the solvent is an amide or a trialkylphosphine oxide. Good results have been obtained in particular with N-methylpyrrolidone, with N,N-dimethylacetamide and with a mixture of tri (n-hexyl)phosphine oxide, tri (n-octyl)phosphine oxide, n-octyldi (n-hexyl)phosphine oxide and n-hexyldi (n-octyl)-phosphine oxide.
In a second, preferred embodiment of the process according to the invention, the reaction is carried out in the presence of an amine, an amide or a trialkylphosphine oxide as cocatalyst. As amides which can be used as cocatalyst, mention may be made of N-methyl-pyrrolidone and N,N-dimethylformamide. As trialkylphosphine oxides which can be used as cocatalyst, mention may be made of the same compounds as those which can be used as solvent in the first embodiment of the invention. An amine is preferably used as cocatalyst, in particular a primary amine. Aliphatic amines comprising from 3 to 25 carbon atoms are preferred. Aliphatic amines comprising from 3 to 22 carbon atoms are particularly preferred. As primary aliphatic amines which can be used in the process according to the invention, mention may be made of n-propylamine, isopropylamine, n-butylamine, isobutyl-amine, t-butylamine, pentylamine and isoamylamine. Among these amines, preference is given most particularly to amines in which the alkyl chain is branched, and more especially to tert-alkylamimes corresponding to the , al formula (I)
in which R
1
, R
2
and R
3
represent C1-C8 alkyl groups. Amines corresponding to formula (I) are, in particular, t-butylamine and the tert-alkylamines Primenes® 81-R and JM-T, sold by Rohm & Haas Company. t-Butylamine is most particularly preferred.
The preferred catalyst-cocatalyst system according to the present invention is the system consisting of a copper (II) compound formed with an organic acid compound and of a primary amine in which the carbon atom next to the NH
2
group is a quaternary carbon atom, i.e. one with no hydrogen atoms. The catalyst-cocatalyst system formed by copper (II) acetyacetonate and t-butylamine is particularly preferred.
The haloalkanes used in the process according to the present invention are generally saturated organic compounds. They preferably have from one to three carbon atoms and preferably at least 2 chlorine atoms. They can also comprise other substituents such as other halogen atoms, alkyl groups or haloalkyl groups. As examples of haloalkanes according to the present invention, mention may be made of dichloromethane, chloroform, carbon tetrachloride, 1, 1,1-trichloroethane and 1,1,1-trichloro-2,2,2-trifluoroethane. Carbon tetrachloride is most particularly preferred.
The olefin used in the process according to the present invention is generally ethylene, propylene or
Janssens Francine
Mathieu Véronique
Connolly Bove & Lodge & Hutz LLP
Padmanabhan Sreeni
Solvay ( Societe Anonyme)
Witherspoon Sikarl A.
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