FR2721312A1 - Process for the production of haloalkanols. - Google Patents

Abstract

Method for the manufacture of a compound (I): R-(CH2)n-OH comprising a first stage in which a compound (III): R-(CH2)n-X is reacted at normal atmospheric pressure or in the region thereof, in a polar aprotic solvent on a salt of a carboxylic (IIa) or dicarboxylic acid (IIb). In a second stage, the ester (IVa) or the diester (IVb) obtained in the first stage undergo saponifying by the action of a base in an aqueous or organic medium, and the compound of formula (I): R-(CH2)n-OH formed when the ester or diester are saponified is then separated. In the formulae R = C1-C10 perhalogenated alkyl; 1 </= n </= 4; R<1> = hydrogen or optionally substituted C1-C5 alkyl; R<2> = C1-C2 saturated alkylene; and X = halogen.

Description

HALOGENOALCANOLS MANUFACTURING PROCESS
The present invention relates to a process for the preparation of haloalkanols of formula
R - (CH2) - - OH (I) in which - R represents a perhalogenated C1-C10 alkyl radical; and - 1 <n <4, in particular 2,2,2-trifluoroethanol.

The main routes of access to 2,2,2trifluoroethanol are, on the one hand, the hydrogenation reactions of trifluoroacetic acid and its derivatives, such as trifluoroacetic anhydride, trifluoroacetyl chloride, fluoral or hydrate fluoral, the hemiacetal of fluoral, and methyl or ethyl or trifluoroethyl trifluoroacetate, and, on the other hand, direct hydrolysis, or via the formation of an acetate, of 2-chloro-1, l, trifluoroethane.

The hydrogenation of trifluoroacetic acid or its derivatives leads to very good yields, but requires particularly harsh conditions (high pressure and temperature), as well as the use of catalysts based on precious metals, the recycling of which appears to be difficult.

The direct hydrolysis of 2-chloro-1,1,1-trifluoroethane in the gas phase, as described in French Patent No. 2,635,101, carried out under very harsh conditions (temperature of 4900C) in the presence of LaPO4 as catalyst, leads to very average results (19% conversion; selectivity: 62%).

peut être effectuée soit en une seule étape sans séparation de l'acétate intermédiaire, soit en deux étapes. Elle conduit généralement à d'assez bons résultats, mais elle s'effectue toujours sous pression, comme c'est le cas par exemple du procédé en milieu solvant aprotique polaire décrit dans la demande de brevet européen EP-A-101 526.Liquid phase hydrolysis or saponification of 2,2,2-trifluoroethyl acetate, as shown in the following equations

can be carried out either in a single step without separation of the acetate intermediate, or in two steps. It generally leads to fairly good results, but it is always carried out under pressure, as is the case for example with the process in a polar aprotic solvent medium described in European patent application EP-A-101 526.

It has now been found, surprisingly, that the reaction for the formation of the intermediate ester can advantageously be carried out at normal atmospheric pressure or in the vicinity of normal atmospheric pressure. The advantages lie in the fact that it is then no longer necessary to have a material resistant to pressure, which can be operated in complete safety, and that the intermediate ester is recovered by continuous distillation as it is used. as it is trained.

où: - Rl représente hydrogène ou un radical alkyl,
substitué ou non, contenant 1 à 5 atomes de
carbone ; et - R2 représente un radical alkylène saturé contenant
1 ou 2 atomes de carbone un composé de formule (III)
R - (CH2)n - X (III) dans laquelle - X représente un halogène, tel que fluor, chlore,
brome et iode ; et - R et n sont définis comme pour le composé (I) ; et dans une seconde étape, on conduit une saponification respectivement de l'ester (IVa) ou du diester (IVb) obtenu à la première étape

The subject of the present invention is therefore a process for the manufacture of a compound of formula:
R - (CH2) - OH (I) in which - R represents a perhalogenated C1-C10 alkyl radical; - 1 # n # 4; according to which: - in a first step, one reacts, to the pressure
normal atmospheric or close to the pressure
normal atmospheric, in an aprotic solvent
polar, on a salt of a carboxylic acid or
dicarboxylic, of formula (IIa) or
(IIb)

where: - Rl represents hydrogen or an alkyl radical,
substituted or not, containing 1 to 5 atoms of
carbon; and - R2 represents a saturated alkylene radical containing
1 or 2 carbon atoms a compound of formula (III)
R - (CH2) n - X (III) in which - X represents a halogen, such as fluorine, chlorine,
bromine and iodine; and - R and n are defined as for compound (I); and in a second step, a saponification is carried out respectively of the ester (IVa) or of the diester (IVb) obtained in the first step

where R, Rl, R and n are as defined above, by
action of a base in an aqueous or organic medium, then
separates the compound of formula (I) formed during the
saponification.

The reaction of the first step is carried out at a pressure generally between about 0.10 bar and 2 bar.

The reaction temperature of the first step is generally between about 50 and 2800C, preferably between about 1200 and 2400C.

In the first step, the compound of formula (III) can advantageously be introduced continuously into the suspension of said salt of the acid of formula (IIa) or (IIb) in said polar aprotic solvent, the ester (IVa) or ( IVb) being recovered continuously, as it is formed. The reaction of the first step can also be carried out by continuously introducing both the compound (III) and the suspension of the salt in the solvent, the ester (IVa) or (IVb) also being recovered continuously as and when measure of its training.

The ester (IVa) or (IVb) formed distils from the reaction medium with the excess or the unconverted part of the compound (III). The gas vents are condensed (ester + compound (III) mixture). The compound (III) can subsequently be recycled.

As salts of acids (IIa) or (IIb), an alkali metal salt, such as Na, K, Rb, Cs, or a salt of an alkaline earth metal, such as Mg, Ca.

Among the compounds of formula (III), which can be used, there may be mentioned in particular
2-chloro-1,1,1-trifluoroethane;
1,2-dichloro-1,1-difluoroethane;
2-bromo-l, 1,1-trifluoroethane 1,2-dibromo-l, l-difluoroethane
2-perfluorohexyl-1-iodoethane.

The polar aprotic solvent is chosen, for example, from the group consisting of sulfolane (tetramethylene sulfone), N, N-dimethylformamide, dimethylsulfoxide,
N, N-dimethylacetamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, 1,3-dimethyl-3,4,5,6tetrahydro-2-pyrimidinone and mixtures thereof. Preferably, sulfolane or 1,3-dimethyl-2-imidazolidinone is used.

To improve the kinetics of the reaction, the latter can be carried out in the presence of a phase transfer agent (crown ethers, polyethoxylated compounds such as oxyethylenated nonyl phenol (marketed under the name ANTAROX CO 990) or Tris [2 (2-methoxyethoxy) ethyl] amine, etc.), in an amount of 0.1 to 5 mol% relative to the salt of the acid of formula (IIa) or (IIb) used.

Furthermore, a molar ratio of the compound of formula (III) to the salt of the acid of formula (IIa) of between approximately 0.2 and 10, preferably between approximately 1 and 7, and a molar ratio of compound of formula (III) on the salt of the acid of formula (IIb) between 0.4 and 20, preferably between 2 and 12. In addition, the concentration of the salt of the acid of formula (IIa) or (IIb) relative to the solvent is advantageously between 1 and 50% by weight, preferably between 5 and 40% by weight.

The saponification of the ester (IVa) or of the diester (IVb) is carried out in a conventional manner by the action of a base such as KOH or K, CO3 in aqueous or organic medium (toluene or xylene for example) at a temperature generally between about 10 ° C. and the boiling point of the solvent used. The compound of formula (I) is recovered by distillation.

The two stages of the process according to the invention can be carried out independently of one another or else in two reactors connected in series.

To better illustrate the object of the present invention, several exemplary embodiments will be described below, by way of indication and without limitation. The abbreviations used are the following ACTRIFE: 2,2,2-trifluoroethyl acetate AK: potassium acetate
ANa: sodium acetate
ACs: cesium acetate
Forane 133a: 2-chloro-l, l, l-trifluoroethane
EXAMPLE 1
290 g of sulfolane and 39.3 g of acetate are introduced into a 500 cm3 glass reactor, equipped with an agitation (turbine type), a heating device and a temperature control system. potassium. The reaction medium is brought to 2100C with stirring, then Forane 133a is continuously introduced in gaseous form at atmospheric pressure, by means of an introduction rod at the bottom of the reactor.

The average flow rate is about 40 g / h and the reaction lasts 6 h 20. The 2,2,2-trifluoroethyl acetate formed is recovered as it is formed by condensation at 150 ° C. of the gaseous vents.

88.5 g of a condensate containing 52.4 g of 2,2,2 -trifluoroethyl acetate mixed essentially with Forane 133a are thus recovered. The conversion of potassium acetate is 99.5% and the selectivity with respect to transformed potassium acetate is 92.5%.

EXAMPLES 2 to 6
Example 1 is repeated, with different conditions for the first step, as reported in
Table 1 below.

The conversion and the selectivity to acetate are shown in Table 1.

TABLE 1

Example <SEP> Sulfolane <SEP> Acetate <SEP> Quantity <SEP> Flow <SEP> of <SEP> Temp- <SEP> Duration <SEP> of <SEP> ACTRIFE <SEP> Conversion <SEP> Selectivity
<tb> engaged <SEP> of acetate <SEP> Forane <SEP> erases <SEP> the <SEP> (g) <SEP> of <SEP> by <SEP> report
<tb> (g) <SEP> engaged <SEP> 133a <SEP> (C) <SEP> reaction <SEP> acetate <SEP> to <SEP> acetate
<tb> (g) <SEP> (g / hour) <SEP> engaged <SEP> (%) <SEP> engaged <SEP> (%)
<tb> 2 <SEP> 290 <SEP> AK <SEP> 39.3 <SEP> 39.6 <SEP> 200 <SEP> 6 <SEP> h <SEP> 10 <SEP> mn <SEP> 43.8 <SEP> 88 <SEP> 87
<tb> 3 <SEP> 293 <SEP> AK <SEP> 39.3 <SEP> 39.6 <SEP> 220 <SEP> 5 <SEP> h <SEP> 30 <SEP> mn <SEP> 52 <SEP > 99.5 <SEP> 91.9
<tb> 4 <SEP> 291 <SEP> AK <SEP> 39.2 <SEP> 39.8 <SEP> 230 <SEP> 4 <SEP> h <SEP> 15 <SEP> mn <SEP> 48.5 <SEP> 100 <SEP> 85.2
<tb> 5 <SEP> 290 <SEP> ANa <SEP> 16.4 <SEP> 40 <SEP> 210 <SEP> 4 <SEP> h <SEP> 5.25 <SEP> 21.5 <SEP> 86
<tb> 6 <SEP> 290 <SEP> ACs <SEP> 20.1 <SEP> 38 <SEP> 210 <SEP> 2 <SEP> h <SEP> 13.5 <SEP> 100 <SEP> 91
<tb>
EXAMPLE 7
In the same setup as for Example 1, 218 g of 1,3 -dimethyl-2-imidazolidinone (DMI) and 29.4 g of potassium acetate are introduced. The reaction medium is brought to 210 ° C. with stirring, then the
Forane 133a in gaseous form at atmospheric pressure by means of an introduction rod at the bottom of the reactor. The average flow rate is 40 g / h and the reaction lasts 3 h 15.

The 2,2,2-trifluoroethyl acetate formed is recovered as it is formed by condensation at 150 ° C. of the gaseous "vents".

86.1 g of condensate are thus recovered, containing 42.1 g of 2,2,2-trifluoroethyl acetate mixed with
Forane 133a.

The conversion of potassium acetate is 100% and the selectivity with respect to transformed potassium acetate is 98%.

EXAMPLE 8
In the assembly used for Example 1, 218 g of sulfolane and 33.8 g of potassium propionate are charged. The reaction medium is brought to 220 ° C. with stirring, then Forane 133a is introduced continuously in gaseous form. The average flow rate is 40.1 g / h and the reaction lasts 4 h. 82.3 g of is thus recovered. condensate containing 42.6 g of 2,2,2-trifluoroethyl propionate.

The conversion of potassium propionate is 99.9% and the selectivity with respect to the transformed potassium propionate is 90.6%.

EXAMPLE 9 Hydrolysis in an aqueous medium
180 g of a 17.6% aqueous potassium hydroxide solution are charged in a glass reactor equipped with a stirrer, a heater, a condenser and a dropping funnel. The reaction medium is brought to 700C, then introduced over 25 min, 73.3 g of 2,2,2trifluoroethyl acetate. At the end of the reaction, the 2,2,2-trifluoroethanol formed is isolated by distillation.

There is thus obtained a conversion of 100% of the 2,2,2-trifluoroethyl acetate and a selectivity with respect to the acetate of 95.6%.

EXAMPLE 10 Hydrolysis in an organic medium
In a glass reactor equipped with a stirrer, a heater, a Dean-Stark and a dropping funnel, 143 g of toluene and 32.8 g of potassium hydroxide are charged. The reaction medium is brought to 700 ° C., then 73.3 g of 2,2,2-trifluoroethyl acetate are introduced over 1 hour 40 minutes. At the end of saponification, the 2,2,2-trifluoroethanol is distilled off and the potassium acetate is filtered before recycling.

The conversion of 2,2,2-trifluoroethyl acetate is 98.3% and the selectivity with respect to acetate is 94.4%.

Claims (12)

1 - Process for manufacturing a compound of formula: R - (CH2) - - OH (I) in which - R represents a perhalogenated C1-C10 alkyl radical; - 1 # n # 4; according to which; - in a first step, we react to the pressure normal atmospheric or close to the pressure normal atmospheric, in an aprotic solvent polar, on a salt of a carboxylic acid or dicarboxylic, of formula (IIa) or (IIb)

where: - R 'represents hydrogen or an alkyl radical, substituted or not, containing 1 to 5 atoms of carbon; and - R2 represents a saturated alkylene radical containing 1 or 2 carbon atoms a compound of formula (III) R - (CH2) n - X (III) in which - X represents a halogen; and - R and n are defined as for compound (I) in a second step, a saponification is carried out respectively of the ester (IVa) or of the diester (IVb) obtained in the first step

saponification. separates the compound of formula (I) formed during the action of a base in an aqueous or organic medium, then where R, Rl, R2 and n are as defined above, by 2 - Process according to claim 1, characterized in that the reaction of the first step is carried out under a pressure of between 0.10 bar and 2 bar. 3 - Method according to one of claims 1 and 2, characterized in that the reaction of the first step is carried out at a temperature of 50O to 2800C. 4 - Method according to one of claims 1 to 3, characterized in that in the first step, the compound of formula (III) is continuously introduced into the reactor in the suspension, previously introduced into the reactor, of the salt of the acid of formula (IIa) or (IIb) in the polar aprotic solvent, the ester (IVa) or the diester (IVb) being recovered continuously as it is formed. 5 - Method according to one of claims 1 to 3, characterized in that in the first step, is continuously introduced into the reactor both the compound (III) and the suspension of the salt of the acid of formula (IIa) or (IIb) in the polar aprotic solvent, the ester (IVa) or the diester (IVb) being recovered continuously as it is formed. 6 - Method according to one of claims 1 to 5, characterized in that one uses, as the salt of the acid (IIa) or (IIb), an alkali or alkaline earth metal salt. 7 - Method according to one of claims 1 to 6, characterized in that one uses, as compound of formula (III), 2-chloro-l, l, l-trifluoroethane, 1,2 -dichloro -1, l-difluoroethane, 2-bromo-l, l, l-trifluoroethane, l, 2-dibromo-l, l-difluoroethane, 2-perfluorohexyl-l-iodo-ethane. 8 - Method according to one of claims 1 to 7, characterized in that the polar aprotic solvent is chosen from sulfolane, N, N-dimethylformamide, dimethylsulfoxide, N, N-dimethylacetamide, N- methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, 1,3-dimethyl-3,4,5,6-tetrahydro-2-pyrimidinone, and mixtures thereof. 9 - Method according to one of claims 1 to 8, characterized in that the reaction of the first step is carried out in the presence of at least one phase transfer agent, at a rate of 0.1 to 5% molar relative to the salt of the acid of formula (IIa) or (IIb) involved. 10 - Method according to one of claims 1 to 9, characterized in that the reaction of the first step is carried out with either a molar ratio of the compound of formula (III) to the salt of the acid of formula ( IIa) of between 0.2 and 10, or with a molar ratio of the compound of formula (III) to the salt of the acid of formula (IIb) of between 0.4 and 20. 11 - Method according to one of claims 1 to 10, characterized in that in the first step, the operation is carried out at a concentration of the salt of the acid (IIa) or (IIb) of between 1 and 50% by weight relative to the solvent. 12 - Method according to one of claims 1 to 11, characterized in that the saponification of the second step is carried out by the action of a base in an aqueous or organic medium, at a temperature generally between about 100C and the boiling point of the solvent used.