Organic compounds -- part of the class 532-570 series – Organic compounds – Halogen containing
Reexamination Certificate
1999-12-30
2002-06-04
Padmanabhan, Sreeni (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Halogen containing
C570S257000
Reexamination Certificate
active
06399840
ABSTRACT:
This application is a 371 of PCT/EP98/02585 filed Apr. 28, 1998, now WO98/50329, published Nov. 12, 1998.
The present invention relates to a process for the preparation of 1,1,1,3,3-pentachlorobutane, more particularly by telomerization between carbon tetrachloride and 2-chloro-1-propene. 1,1,1,3,3-pentachlorobutane is of considerable industrial value since it leads, by fluorination, to the corresponding pentafluoro derivative (HFC-365mfc) which can be used in particular as a third generation swelling agent or solvent, which has no harmful effect on the ozone layer and does not contribute to the global warming of the planet by the greenhouse effect.
R. Freidlina et al. (Bull. Acad. Sci. USSR, 28, 1766-69, 1979) obtained 1,1,1,3,3-pentachlorobutane in low yield by reaction between carbon tetrachloride and 2-chloro-1-propene in the presence of iron pentacarbonyl as catalyst, in ethanol or isopropanol. The low yield, on the one hand, and the high toxicity of the catalyst, on the other hand, are such that this synthetic method will be difficult to use industrially.
Another route of access to 1,1,1,3,3-pentachlorobutane, described recently by Kotora and coworkers (React. Kinet. Catal, Lett. 44(2), 415-9, 1991), consists in reacting 1,1,1-trichloroethane with 1,1-dichloroethane in the presence of cuprous chloride and amine. The yield obtained is low (8%) and this synthetic method would thus also be difficult to exploit industrially.
The invention is thus directed towards providing a process which makes it possible to gain access, in a single step and with the use of readily available reagents, to 1,1,1,3,3-pentachlorobutane in excellent yield.
The invention thus relates to a process for the manufacture of 1,1,1,3,3-pentachlorobutane by reaction between carbon tetrachloride and 2-chloro-1-propene in the presence of a catalyst comprising at least one copper (I) compound or a copper (II) compound. In general, copper (II) compounds are preferred.
The copper (I) or (II) compound is preferably chosen from copper halides, copper carboxylates, mixed copper salts and complexes formed with neutral ligands.
The fluorides, chlorides, bromides or iodides are found in particular among the copper (I) or (II) halides the chlorides and iodides are preferred. Copper (II) chloride is particularly preferred.
The hydroxyhalides are found in particular among the mixed copper (I) or (II) salts.
Salts formed from carboxylic acids such as acetic acid, propionic acid, butyric acid, cyclohexanebutyric acid-or benzoic acid are found in particular among the copper (I) or (II) carboxylates. Copper (I) or (II) acetates, i.e. the salts formed using acetic acid, are preferred. Copper (II) cyclohexanebutyrate is most particularly preferred.
Complexes formed with neutral ligands such as phosphines, for instance triphenylphosphine or acetylacetone, are found in particular among the complexes formed with copper (I) or (II) compounds. Copper (II) acetylacetonate is preferred.
Advantageously, the catalyst is chosen from copper (I) or (II) acetate, copper (II) cyclohexanebutyrate, the complex formed between cuprous chloride and triphenylphosphine, copper (II) acetylacetonate, copper (II) hydroxychloride, copper (I) chloride, copper (I) iodide and copper (II) chloride. Among these catalysts, copper (II) chloride, copper (II) acetate, copper (II) hydroxychloride, copper (II) cyclohexanebutyrate and copper (II) acetylacetonate are preferred.
In a batchwise process, the molar ratio between the copper compound used and the 2-chloro-1-propene is generally greater than or equal to 0.001. Advantageously, it is greater than or equal to 0.002. Preferably, it is greater than or equal to 0.005. The molar ratio between the copper compound used and the 2-chloro-1-propene is usually less than or equal to 5. Advantageously, it is less than or equal to 1. Preferably, it is less than or equal to 0.5. In a particularly preferred manner, this ratio is greater than or equal to 0.01 and less than or equal to 0.1.
In a continuous process, the molar ratio between the catalyst used and the 2-chloro-1-propene ranges approximately between the same limits as in a batchwise process,. although it can, however, reach a value of 50.
It is understood that the amount of catalyst used is expressed, in a batchwise process, relative to the initial amount of 2-chloro-1-propene used and, in a continuous process, relative to the stationary amount of 2-chloro-1-propene present in the reactor.
The molar ratio between the carbon tetrachloride and the 2-chloro-1-propene used can vary within a wide range. This ratio is generally greater than or equal to 0.1. Advantageously, this ratio is greater than or equal to 0.5. Preferably, it is greater than or equal to 1. Generally, this ratio is, however, less than or equal to 20. Advantageously, this ratio is less than or equal to 10. Preferably, this ratio is less than or equal to 8.
The reaction conventionally takes place at a temperature greater than or equal to room temperature. Preferably, the temperature is greater than or equal to 40° C. Advantageously, it is greater than or equal to 80° C. In general, the reaction temperature does not exceed 2000° C. Advantageously, in particular with copper (II) hydroxychloride as catalyst, the reaction temperature is greater than or equal to 90° C. and is preferably greater than or equal to 100° C. It is usually less than or equal to 150° C., more precisely less than or equal to 140° C. With copper (II) hydroxychloride, it is most particularly advantageous to carry out the reaction at a temperature close to 130° C.
The reaction time in a batchwise process, or the residence time in a continuous process, depend on various parameters such as the reaction temperature, the concentration of reagents and of catalyst in the reaction mixture and their molar ratios. In general, as a function of these parameters, the residence time or the reaction time can range from 5 seconds to 20 hours.
The pressure is usually greater than or equal to atmospheric pressure and less than or equal to 15 bar. It is advantageously less than or equal to 10 bar. Since the telomerization reaction is generally carried out in liquid phase, the pressure is advantageously chosen, as a function of the temperature of the reaction medium, so as to keep the reaction medium essentially in condensed phase.
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, a trialkyl phosphate or another polar solvent.
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 nitrites, in particular acetonitrile, propionitrile or adiponitrile, and aromatic nitrites, in particular benzonitrile or tolunitrile. Among the nitrites, 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 hexamethylphosphoramide. 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 (R1R2R3)PO, in which R1, R2 and R3 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. Among the trialkyl phosphates which can be used as reaction solvent, mention may be made in particular of the compounds of formula (RO)
3
PO, in which R represent
Janssens Francine
Mathieu Véronique
Schoebrechts Jean-Paul
Padmanabhan Sreeni
Solvay ( Societe Anonyme)
Witherspoon Sikarl A.
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