CS262373B1 - Process for preparing fluorinated alkanoles - Google Patents

Abstract

The production of fluorinated alkanols is addressed of formula (I) wherein R 8 is hydrogen or alkyl having a carbon number of 1 to 3, R2 is hydrogen or alkyl having carbon numbers And n is 1-6. Said alkanols are produced by the reaction of tetrafluoroethene s aliphatic primary and secondary alcohols having 1 to 6 carbon atoms ultraviolet radiation and initiators of radical reactions. Like initiators are organic azo compounds, e.g., azo-bis-isobutyronitrile, organic peroxy compounds such as dibenzoyl peroxide. , and di (chlorobenzoyl) peroxide, followed by benzoin H / C-F. / -CRIR2 (I) and its derivatives, and ketones, e.g., acetone. and acetophenone. The preparation is carried out in a flow-through or closed photoreactor at temperatures -60 to 110 ° C. Used ultraviolet radiation ranges from 180 to 450 nm. Fluorinated alkanols serve as special solvents, as surfactant additives substances, they are used in the preparation of substances for fabric finishing and monomer synthesis for microelectronics and optoelectronics.

Description

This invention relates to fluorinated alkanols of the formula ^{H / C} 2 ^{F-44 R1R2}

OH

Wherein R is hydrogen or alkyl having 1 to 3 carbon atoms, R is hydrogen or alkyl having 1 to 6 carbon atoms, and is 1 to 6, by reacting tetrafluoroethene with aliphatic alcohols having 1 to 8 carbon atoms under the influence of ultraviolet radiation and radical initiators.

Fluorinated alkanols are prepared by a variety of synthetic procedures and methods. From the point of view of the last synthetic step, substitution, addition and reduction reactions are used in the synthesis of these compounds. Conversions of terminal polyfluoroalkyl iodides and polyfluoroalkyl bromides to the corresponding fluorinated alcohols have been used in the substitution reactions. Reductions include several methods. By catalytic reduction of fluorinated ketones, secondary alcohols are obtained, catalytic reduction of perfluorocarboxylic acids gives corresponding primary fluorinated alkanols. Reductions of the functional carboxylic acid derivatives which are carried out with various complex hydrides also provide the corresponding alkanols, while the functional dicarboxylic fluoroacid derivatives yielded the corresponding fluorinated diols. Addition reactions include several types. These include the addition of fluorinated or non-fluorinated organometallic reagents to the carbonyl group of the non-fluorinated or fluorinated aldehydes, resulting in the formation of primary and secondary fluorinated alcohols. Furthermore, it is the addition of formaldehyde to fluorinated alkenes in hydrogen fluoride environment or with catalysis of alkali metal fluorides. Finally, it is the addition of alkanols with fluorinated alkenes to form primary, secondary and tertiary fluorinated alkanols.

2

Also disclosed in the literature is the preparation of fluorinated alkanols of the H / C, F. (-CR R / OH) type, 12 of 4 n wherein n, R and R are as defined above by addition of aliphatic alcohols to tetrafluoroethene. Additions are initiated by radical initiators based on organic peroxides or azo compounds, further initiated by gamma-radiation ® ° Co. Initiators do not act on their own, but must first be staggered to trigger an addition reaction. The decomposition is carried out thermally in a reaction vessel which also contains the reaction amount of tetrafluoroethene. At a decomposition temperature of, for example, 80 to 150 ° C, the pressure of the reaction system is considerable, and it is therefore necessary to work in pressure reactors for medium and high pressures. Initiation of addition of gamma-radiation ^to Co requires work in special operations. The preparation of fluorinated alkanols of general formula H / C ₂ ^F 4 / _n -C / OH / RR is further described in the literature, where n, R and R are as defined above by photochemically initiated addition of simple aliphatic alcohols to tetrafluoroethene. This method uses only a narrow portion of the radiation emitted by, for example, medium-pressure or high-pressure mercury lamps or, for example, xenon lamps.

The disadvantages of the prior art are eliminated by the process for producing the fluorinated alkanols of the general formula

H / C ₂ ^F 4 / _n -C / OH / R ¹ R ² ,

Wherein n is 1 to 6, R is hydrogen or alkyl of 1 to 3, R is hydrogen or alkyl of 1 to 6, reactions, tetrafluoroethene with aliphatic alcohols of 1 to 8

HC / OH / R ¹ R ²

Wherein R and R are as defined above, according to the invention. It is based on the fact that the reaction is carried out under the simultaneous action of ultraviolet radiation from 180 to 450 nm and radical initiators selected from the group consisting of organic azo compounds, preferably azo-bis-isobutyronitrile and / or organic peroxy compounds, preferably di- bis-iso-benzoyl peroxide and di (chlorobenzoyl) peroxide, and / or benzoin and its derivatives and / or ketones, preferably acetone and acetophenone, at temperatures of -60 to 110 ° C. Pressure is not a determining factor; it usually reaches values of 0.1 to 2 MPa. The reaction time depends on the reactor volume, the amount of alcohol present in the reactor, the amount of tetrafluoroethene in the batch glass reactor, the amount of initiator, the radiation intensity, the pressure and the reaction temperature.

The choice of initiators is conditional on the absorption of radiation in the range from 250 nm to greater wavelengths at the concentrations used. Organic azo compounds, preferably azo-bi-isobutyronitrile, organic peroxy compounds, preferably dibenzoyl peroxide, di (chlorobenzoyl) peroxide, diisopropylpercarbonate (i. E. diisopropoxycarbonylperoxide], benzoin derivatives, preferably O-methylbenzoin and / or O-isopropylbenzoin and / or alpha-phenylbenzoin, ketones, preferably acetone and acetophenone. In the flow-through configuration, the radiation source is either completely immersed in the liquid phase or may be located above the liquid phase inside the reactor. In irradiation from the outside, the radiation can be appropriately rectified by reflective surfaces of different shapes. The ultraviolet radiation effective for the reaction is in the region of 180-450 nm, preferably in the region of 300-450 nm.

The process of the invention has several advantages. The simultaneous use of chemical initiators and ultraviolet radiation makes it possible to significantly reduce the reaction temperature, if desired, and to perform photochemical decomposition of the reaction initiators even at low temperatures, while the rate of reaction can be easily controlled by the intensity of the radiation. The process according to the invention also allows for better utilization of the emitted radiation, since sources which emit exclusively in the region of 300 to 400 nm can be used.

The process according to the invention is further described in several exemplary embodiments.

Example 1

In a submerged photochemical reactor containing 70 ml of 2-propanol and 1.9 g of azo-bis-isobutyronitrile, tetrafluoroethene was fed at 16-25 ° C at a rate of 5 hours to react. The source of radiation was a mercury lamp 80 W and its radiation passed through the laboratory glass. The reaction mixture was rectified and 3,3,4,4-tetrafluoro-2-methyl-2-butanol was collected as the main product in the range of 116-118 ° C in a yield of 7.6 g.

with

Example 2

An ampoule of Simax glass containing 80 ml of methanol, 0.5 g of dibenzoyl peroxide, 12.5 g of tetrafluoroethene was externally irradiated with a 200 W xenon lamp. The system was surrounded by a metal reflective surface, the irradiation time was 9 hours at 15-25 ° C. . The reaction mixture was then rectified to give 5.8 g of 2,2,3,3-tetrafluoropropanol and 2.1 g of 1H, 1H, 5H-octafluoropentanol (138-142 ° C). The distillation residue and the intermediate fraction were 3.4 g. At an irradiation time of 18 hours, 2.3 g of 1H, 1H, 7H-dodecafluoroheptanol having a boiling point of 170-171 ° C were isolated from the reaction mixture. Chromatography revealed the presence of 1H, 1H, 9H-hexadecafluoroonanol and IH, 1H, 11H-eicosafluorundecanol in the distillation residue.

Example 3

In a submerged photochemical reactor containing 100 ml of 2-butanol and 2 g of O-isopropylbenzoin, tetrafluoroethene was introduced at -30 to -40 ° C for 6 hours at a rate sufficient to react. The source of radiation was an ultraviolet lamp according to Example 1. The reaction mixture was then rectified and 1,1,2,2-tetrafluoro-3-methyl-3-pentanol was collected as the main product at temperatures of 136-139 ° C and with a yield of 11.2 G.

Example 4

Tetrafluoroethene was introduced into the immersion photochemical reactor containing 190 ml of ethanol and 5.1 g of di (chlorobenzoyl) peroxide at 60 ° C and under a pressure of 0.85 MPa for 6 hours. The source of radiation was an ultraviolet lamp according to Example 1. The reaction mixture was then rectified and 3,3,4,4-tetrafluoro-2-butanol was collected as the main product in the range of 108 to 110 ° C in a yield of 25.7 g. starting from 2-butanol (190 ml) 1,1,2,2-tetrafluoro-3-methyl-3-pantanol in a yield of 32.4 g, which was collected at 133-135 ° C.

Example 5

The reactor of Example 1 contained a starting amount of 70 ml of 2-propanol and 10 ml of acetone. The reaction was conducted as in Example 1 and 5 ml of acetone was added over 3 hours of irradiation. The main product, ie, 3,3,4,4-tetrafluoro-2-methyl-2-butanol, was isolated by rectification in a yield of 12.8 g, the distillation being 9.4 g.

The fluorinated alkanols prepared according to the invention have a number of uses. Low boilers serve as special solvents, they are also used as chemical intermediates for the preparation of surfactants, in the synthesis of monomers for microelectronics and optoelectronics, and in the preparation of fabric treatment agents.

Claims (1)

SUBJECT OF THE INVENTION A process for the preparation of fluorinated alkanols of the general formula H / CzF / n-CR ¹ * ² OH Wherein n is 1 to 6, R is hydrogen or alkyl of 1 to 3, R is hydrogen or alkyl of 1 to 6, reacting tetrafluoroethene with aliphatic alcohols of 1 to 8 HC / OH / R ¹ R ² Wherein R and R are as defined above, characterized in that the reaction is carried out in the presence of ultraviolet radiation from 180 to 450 nm and radical initiators selected from the group consisting of organic azo compounds, preferably azo-bis-isobutyronitrile, and / or organic peroxy compounds, preferably dibenzoyl peroxide and di / chlorobenzoyl / peroxide, and / or benzoin and its derivatives and / or ketones, preferably acetone and aoetophenone, at temperatures of -60 to 110 ° C. Severography, n. P., MOST Price 2,40 Kčs