DE2332097C2 - Process for the preparation of certain branched chain perfluorononanes and the compounds so prepared as such - Google Patents

Description

FC-CF + 107 kcal

When a considerable amount of heat is released, fragmentation products are often formed. Addition reactions of Fluorine on double bonds of perfluoroolefins continues to run in both the liquid and the gaseous phase a radical mechanism (A. S. Rodgers, J.

Phys. Chem. 69, 254 (1965)), so that the coupling of two C radicals can lead to dimeric products to a considerable extent (WT Miller, Jr., and SD Koch, Jr, J. Am. Chem. Soc. 79. 3084 (1957 )). In order to keep the formation of these undesirable by-products low, the olefins used were _{diluted with inert solvents such as CCl 3} F or CF ₂ Cl - CFCl ₂ and, in addition, the fluorination at low temperatures (down to -100 ° C.) and / or with dilution of the fluorine stream carried out. However, such measures have a disadvantageous effect on the reaction rate and the utilization of the starting materials, in particular fluorine, and require additional steps in the work-up.

Furthermore, the use of special

Fluorination apparatus proposed by which the control of the exothermic reaction facilitated shall be. In a U-shaped copper vessel introduced by W. T. Miller (UK Patent 8 39 034, June 29, 1960, Chemical

Abstracts 54, 24 393e (1960)) the fluorination takes place in the vapor phase over a liquid surface which is constantly renewed by mechanical agitation. Another variant is the apparatus for liquid phase fluorination, which has been developed by WT Miller, Jr. and others (WT Miller, Jr., JO Stoffer, G. Fuller and AC Currie, J. Am. Chem. Soc. 86, 51 (1964)). A high-speed metal stirrer made of a nickel mesh is used to finely distribute the gassed fluorine; the reaction temperature is to -75 ° to -12O ⁰ C. The fluorine is diluted with N? and / or of the fluoroolefin with CCI ₃ F.

The subject of the invention is now the method indicated in the preceding claims for the preparation of the perfluorononanes of the formulas I and ti II and the perfluorononanes thus produced as such.

The reaction is preferably carried out in the absence of inert solvents such as CCl ₃ F or CCl ₂ F ₂ , since the separation is then simplified. Their use is possible, but without advantage. The dilution of the fluorine with inert gases leads to a reduction in the yield. The perfluorononane of formula I is preferably in the temperature range from + 20 ° to +70 ⁰ C and the perfluorononane of formula II is preferably prepared in the range of 90 ° to 110 ° C. During the fluorination, the same nonane is formed from both perfluorononenes, whereby it is only a question of the reaction temperature to what extent the nonane of the formula I or the formula II /

arises. so (CF ₃ ) ₂ CF

The reaction according to the invention is generally carried out in the manner of customary gas-liquid reactions, by pouring the fluorine through a frit or an equivalent distribution element in fine bubbles into the lower end of a liquid column filled with the 55 (CFj) ₂ CF nonenes of the formula III and / or IV. These \,

The liquid column expediently has a height which is greater than its diameter. A height which is at least three times, in particular more than (CFj) ₂ C five times the diameter of the liquid column is preferred. Adequate mixing is ensured by the rising gas bubbles. Additional mechanical agitation is possible, but without any advantage.

The height of the liquid column is not critical for the course of the method according to the invention. To but To avoid exhaust gas problems, it is useful to her - depending on the reaction temperature and the Dosage of fluorine - to give such a level that at least in the beginning of the reaction everything or practically everything fluorine is implemented. It is advantageous to add a second, similar or identical one behind the reaction vessel switch, which is also filled with perfluoronones and in which fluorine that has not been used is still converted. The continuous configuration of the method according to the invention is therefore also advantageous per se known way, e.g. B. by adding fresh Perfluornonen in the upper part of the reactor and Decrease in the fluorination product at the lower end, followed by separation of the starting product by distillation and fluorination product.

The dosage of the fluorine is also not critical, as long as there is even beading of the introduced Fluorine remains guaranteed. Preferably, as much fluorine is gassed in as is reacted, d. H. the bigger the The layer height of the submitted nonene, the higher the rate of fluorine used can be selected. The process takes place preferably at normal pressure, but also allows the use of overpressure. It is expediently carried out in the absence of light (increased fragmentation) The reaction is carried out under conditions in which significant amounts of fluorine pass through the liquid phase, it is advisable to to keep the gas space above the liquid phase small and / or to cool it to avoid a gas phase reaction leading to fragmentation and to a Deterioration in the yield leads to

As a material for the reactor and frit, any can be used against Fluorine resistant material can be used, such as steel, copper, platinum, the reactor can also be used z. B. be lined with polytetrafluoroethylene. If the fluorine is sufficiently free from hydrogen fluoride, glass, quartz or ceramic can also and advantageously be used be used as a material.

As perfluorononenes for the addition reaction according to the equation

C0F18 t F ₂ * CgT ₂ O

the olefins mentioned below are used in pure form or as a mixture of isomers:

(CFj) ₂ CF F

Perfiuor-3-isopropyl-

2-methyl-3-pentene,

Bp 110-111 ° C / 760 torr

CF ₃

, Perfluoro-3-isopropyl-

C - CF ₂ --CF ₃ 2-methyl-2-pentene,
> Bp 114-115 ° C / 760 torr

(IV)

They can be obtained easily and in good yield by trimerizing hexafluoropropene (e.g. like S. P. v. Halasz, F. Kluge and Th. Martini, Chem. Reports 106, 2950-2959 (1973)).

By the addition of fluorine to III and IV, respectively, which differ only by the position of their double bond is produced at temperatures of preferably 20 ° -70 ⁰ C to about 95% of theory the structurally uniform perfluorononane I of the formula

.. (CFj) ₂ CF
\

CF ₂ CF ₃

/ \
(CF ₃ ) ₂ CF F

Perfluoro-3-isopropyl-

2-methyl-pentane

Bp 127-127.5 ° C / 760 torr

If the reaction of fluorine with the olefins III and IV is carried out in the same way, but at preferably 90 ° -110 ⁰ C, is formed, presumably due to an isomerization during the fluorination step (migration of a trifluoromethyl

Group) predominantly the perfluorononane II with the formula

(CF ₃ J ₂ CF
\

CF ₂ CF ₃

/ \
CF ₃ CF ₂ CF,

(II)

Pcrnuor-3-ethyl-2,3-dimethyl-penlan Bp 135-136 C7755 torr

By treating the perfluorononane I with elemental fluorine at 100 ^° C., no isomerization and formation of the perfluorononane of structure 11 can be obtained. The composition and structures of the compounds I and II are ^{secured by elemental analysis and by measuring the infrared, mass and 19} F-NMR spectra.

The perfluorononanes I and II, which are easily accessible by the route according to the invention, have not yet been found known. They represent valuable products, which are due to their thermal and chemical stability as well as their electrical properties for use as hydraulic fluids, dielectrics, propellants suitable for turbines, heat exchangers or coolants in electrical and mechanical systems. Farther the perfluorononanes produced can be used as inert solvents or reaction media, especially with reactions with elemental fluorine. Furthermore, the perfluorononanes are due the found gas solubility and surface tension suitable as an active ingredient in blood substitutes.

It was previously known to be advantageous for the addition of fluorine to double bonds in the liquid phase To undertake a lower temperature, which requires a considerable amount of equipment, or with diluents to work.

In contrast, it was surprising that the perfluorononanes mentioned are also in the liquid phase without diluent at normal or higher temperature in high yield with fluorine to perfluorononanes have it implemented.

The avoidance of this low-temperature technology and the associated costs by the inventive Process represents a considerable technical advance.

The new compounds of the formula CgF ₂ O are suitable as active ingredients in blood substitutes because of their high solubility for oxygen. The experimentally determined Löslichkeil for oxygen at 37 ° C was 41.9 ml O _2/100 ml. In contrast, is the solubility of compounds that have been used for this purpose, lower. This can be seen from the following table.

ml of CVlOOmI soluble
(at ° C)

Vapor pressure in torr (at ⁰ C)

F-tributylamine

F-decalin

F-2-butyl tetrahydrofuran

41.9 (37 ° C) 40.3 (37 ° C) 40.3 (25 ° C) 48.5 (37 ° C)

20 (36 ° C) 2.5 (37.5 ° C) 13.6 (37.5 ° C) 51 (37.5 ° C)

The oxygen solubility of the known compounds was taken from J. G. Riess, M. Le Blanc, Angew. Chemie 90 (1978), p. 658. The steam pressures of the other compounds come from E P. Weseler et al "J. Fluorine Chem. 9 (1977), p. 137. That also called F-2-butyltetrahydrofuran with the s high oxygen solubility of 48.5 ml / 100 ml because of the high vapor pressure at 37.5 ° C of 51 mm Hg no practical importance, since in the range of 50-60 mm Hg according to L. C. Clark there is a risk of dangerous gas embolism (see L. C. Clark

ίο et al. Fed. Proa 34, 1468 (1975). In addition, it is with Safety toxic (Angew. Chemie, op. Cit., Pp. 659 and 666).

The higher vapor pressure of CqF ₂ O compared to F-tributylamine and F-decalin at body temperature

ii facilitates the desired exhalation of the active ingredient after application (N. Schnoy et al., Anaesthesist, 28, 504 (1979)).

The compounds CqF ₂₀ according to the invention are therefore superior to the known perfluoro compounds in this respect.

The substances previously used for blood substitutes can only be used to a limited extent. the Stability of the emulsion of the fluorine compounds in vivo is insufficient in some cases, although the other results are encouraging. There is therefore a considerable need for new means, since the There is hope that these do not have the disadvantageous properties of the known products (cf. Applied Chemistry, a. a. O, p. 666 "Tasks of the

jo chemist «). To that extent, there would be a technical advance already before, even if the new compounds were not characterized by improved oxygen solubility.

example 1

The experimental set-up for the elementary fluorination of olefins III and IV consists of three series-connected, dried and nitrogen-flushed DURAN® glass traps, each with a capacity of about 300 ml. In the first case (A) - equipped with an internal thermometer and a to the bottom of the case extensive and in a glass frit (size G 1) ending gas inlet tube - are at 3O ⁰ C 450 g (1 mol) of perfluorononene (isomer ratio of III: IV like 29.7: 65.9%) with a layer height of 20 cm above the glass frit. Trap A is warmed with a water bath.

The subsequent trap B is _{kept at -78 ° C with solid CO 2} and is used to collect it

so low-boiling fission products. The following trap C, like trap A, provided with a glass filter and filled with the same perfluoronone - is ^{intended to absorb excess fluorine (temperature of the trap: 30 °} C.) (exhaust gas cleaning).

Elemental fluorine is taken from a standard steel bottle with a previously calibrated Differential pressure flow meter measured and introduced into trap A. In front of the flow meter as well Between the traps A and B there is a riser manometer for observing the dynamic pressure and attached as a safety valve. The measuring devices are made with VOLTALEF®-Oel, 10 S (poly-trifluorochloro-ethylene) filled; the ground joints are sealed with VOLTALEF, Graisse 90 (F. UGINE KUHLMANN).

In the course of 45 hours, a total of 1.4 mol of fluorine are introduced at a rate of 0.7 l / h. the

⁸¹ = protected designation

The internal temperature rises temporarily to 34 ° -36 ° C. After introduction, the weight gain of the contents of the trap (A) is 26 g; in case B 8 g are condensed, predominantly consisting of low boilers of the formula C _n F _{2n + 2} with η <9.

GC analysis (5.0 m 10% hexafluoropropene epoxy polymers on Chromosorb W-AW DMCS 80-100 mesh, 80 ° C isothermal, 60 ml He / min) gives for the crude product of trap A has the following composition (area percent):

C ^ F ₂₀ (I)

C ₉ F ₁₈ (IIl) -I- (IV)

miscellaneous

94.3%
1.8%
3.8%

The subsequent fractionated destination over a 30 cm long VIGREUX column gives a fraction of 444 g (0.91 mol) I ₁ corresponding to a 96% yield, based on a boiling point of 127 ° -127.5 ° C / 760 Torr converted perfluoronones (used with 96% purity).

Elemental analysis: C9F20 (I)
Calculated: C 22.15%; F 77.85%; Molar mass 488.1
Found: C 22.2%; F 77.1%; Molar mass 469

(mass spec.)
n ²⁴ (Ne 632.8 nm) 1,203

from 0.9 l / h a total of 0.84 mol fluorine introduced. The internal temperature in the case of A rises temporarily to 106 ° - 108 ⁰ C on. After the introduction, a decrease in weight of 17.5 g is found in case A; in case B there are 36 g of condensate, mainly consisting of low boilers.

The GC analysis (conditions cf. Example 1) gives the following composition for the crude product in case A. (Area percent):

C ₉ F ₂₀ (II)
C ₉ F ₂₀ (I)

C ₉ F ₁₈ (III) + (IV)
miscellaneous

57.3%
2.5%
8.0%

32.2%

In the fractional distillation over a 30 cm long VIGREUX column, a fraction of 109.5 g (0.22 mol) II is obtained at a boiling point of 135 ° -136 ° C / 755 Torr, corresponding to a 42% yield, based on converted perfluoronones (used with 96% purity).

Elemental analysis: C ₉ F ₂ o (II)
Calculated: C 22.15%; F 77.85%; Molar mass 488.1
Found: C 21.7 o / _o; F78.2%; Molar mass 469
" ^J (mass spec.)

n ^M (Ne 632.8 nm) 1,201

As is often the case with fluorine compounds, this is done by mass spectrometry Molecular weight found reduced by the mass of a (split off) fluorine atom

The ¹⁹ F-NMR spectrum of I - recorded at 3O ⁰ C with CCl ₃ F as internal standard - gives signals at 67.5, 70, 78, 108, 167 and 170 ppm in the middle of relative intensities 6: 6: 3: 2 : 2: 1. The coupling constants

JcF ₃ (CF ₃ CF ₂ VCF (tcniär)

are 213 Hz.

Example 2

In the test arrangement according to Example (1), in-which is, however, provided the trap A with an outer water cooling for the upper part and a Heizölbad for the base, at a temperature of 104 ⁰ C 270 g (0.6 mol) of Perfluornonengemisches from example (1) fluorinated

The ¹⁹ F-NMR spectrum of II - measurement conditions as in Example 1 - shows the expected signals for groups a to e in the intensity ratio of a: b: c: d: e as in 3 : 6: 6: 4: 1 according to structure

35

40 (CFj) ₂ CF

C (CF ₂ CFj) ₂

F ₃ C

o _a at 57, Oi, 66, ö _c 77.5, ö _d 97 and 6 _C 160 ppm.

The signal for the CF group shows a weak split.

tX 215/158

Claims (4)

Patent claims: 1. Process for the preparation of Perfiuornonanen of the formulas (CF ₃ ), CF CF ₁ CF ₃ (CFj) ₂ CF F and (CF ₃ ), CF CF ₇ CF ₃ CF ₃ CF ₂ CF ₃ based on the conversion of perfluoroolefins with elemental fluorine, characterized by that one perfluomonene of the formulas (CF ₃ ) ₂ CF F C = C (III) (CF ₃ J ₂ CF CF ₃ and (CF ₃ ) ₂ CF C-CF ₂ CF ₃ (IV) (CF ₃ ) ₂ C or their mixtures with elemental fluorine at temperatures from 0 ° to + 8O ⁰ C (production of I) or at temperatures from + 80 ° to + 12O ⁰ C (production of II). 2. The method according to claim I _1, characterized in that the reaction is carried out without a diluent. 3. Perfluorononane of the formula (CF ₃ ) ₂ CF CF ₂ CF ₃
\ / (CFj) ₂ CF F 4. Perfluorononane of the formula (CFj) ₂ CF CF ₂ CF ₃ CF ₃ CF ₂ CF ₃ Perfluoroalkanes are non-flammable and resistant to acids, alkalis and oxidizing agents and belong to them the most stable known organic substances. Because of their thermal and chemical stability as well as their dielectric properties, there are numerous areas of application for them, so that a special one Interest in profitable and simple procedures for -, production of representatives of this class of substances consists. Processes are known in which perfluoroalkanes by reacting the corresponding saturated or unsaturated hydrocarbons in the vapor state can be produced with cobalt trifluoride (E. J. Barber, L. L. Burger and G. H. Cady, J. Am. Chem. See. 73, 4241 (1951)). The fluorination of hydrocarbons with elemental fluorine - usually with dilution with Nitrogen - comes from reaction in the gas phase ι -, silver-plated copper contacts (G. H. Cady, A. V. Grosse, E. J. Barber, L. L. Burger, and Z. D. Sheldon, Ind. Engng. Chem. 39, 290 (1947)). In these processes, however, mostly high proportions occur as by-products Fragments as well as on dimeric, trimeric and polymeric products (tar formation). Furthermore falls with this Reaction type for each newly formed C-F bond an equivalent amount of hydrogen fluoride. In the electrofluorination of hydrocarbons, the yield is more or less good the corresponding perfluoroalkanes (J. H. Simons et al., J. Electrochem. Soc. 95, 47 (1949)), but this is Synthesis path connected with a considerable amount of equipment and energy and partly leads to Fragmentation of the carbon framework. It is also known that perfluoroolefins with elemental Can convert fluorine with moderate yields to the corresponding perfluorinated alkanes (W. A. Sheppard and Sharts, C. M., Organic Fluorine Chemistry, 1st Ed., p. 53, Benjamin, New York 1969; E. Research in Methods of organic chemistry «(Houben-Weyl-Müller), 4. Ed., Vol. V / 3, p. 12, Thieme, Stuttgart 1962; J. M. Tedder in Advances in Fluorine Chemistry (Stacey-Tallow-Sharpe), 1st ed., Vol. 2, p. 104, Butterworths, London 1961). As in the reaction according to the equation