Chemistry: electrical and wave energy – Processes and products – Processes of treating materials by wave energy
Patent
1990-10-31
1993-11-02
Niebling, John
Chemistry: electrical and wave energy
Processes and products
Processes of treating materials by wave energy
20415794, C07C 4100
Patent
active
052581101
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a process for the preparation of peroxidic perfluoropolyalkylenoxy compounds, more commonly referred to as peroxidic perfluoropolyethers.
In particular, the present invention relates to a process for preparing peroxidic perfluoropolyethers containing perfluoroalkylenoxy units of formulae (CF.sub.2 --CF.sub.2 O) and (CF.sub.2 O). These compounds are prepared, according to the art, by reacting tetrafluoroethylene with oxygen under irradiation with ultraviolet light.
This technique exhibits the drawback of being delicate and complex, as it requires the use of ultraviolet radiation generators and of reactors of suitable construction in order to permit the radiation to penetrate and to spread inside the reacting phase. Furthermore, since these reactions are usually conducted at very low temperatures, even lower than -50.degree. C., it is necessary to have available efficient means of eliminating the heat associated with the generation of the ultraviolet radiation. Moreover, the reaction yield and the product structure are strongly affected by the amount and distribution of the radiation inside the reaction medium, which considerably limits the desired production flexibility provided by a given reactor.
U.S. Pat. No. 4,460,514 relates to the preparation of non-peroxidic oligomers of (CF.sub.2 O) having a --CF.sub.2 --COF end group. These oligomers are useful for the preparation of s-triazines with perfluoroxymethylene substituent groups. In example IIa, perfluoro-3-methylbutene-1, CF.sub.2 .dbd.CF--CF(CF.sub.3).sub.2, is reacted, in the gas phase, with oxygen in the presence of CF.sub.3 OF without the use of ultraviolet radiation, which affords, at the end of the reaction, the unreacted olefin, (CF.sub.3).sub.2 CF--CFO and a small amount of non-peroxidic oligomers of (CF.sub.2 O) having a CF.sub.2 --COF end group.
It has now, surprisingly, been found that the reaction for preparing peroxidic perfluoropolyethers containing perfluoroalkylenoxy units of formulae (CF.sub.2 --CF.sub.2 O) and (CF.sub.2 O) may be effected without use of ultraviolet radiation if C.sub.2 F.sub.4 is reacted with oxygen in a solvent and in the presence of particular reagents.
It is, thus, an object of the present invention to provide a process which affords peroxidic perfluoropolyethers containing perfluoroalkylenoxy units of formulae (CF.sub.2 --CF.sub.2 O) and (CF.sub.2 O) without using ultraviolet radiation or using UV-irradiation only as a complementary measure.
Another object is to provide a process which is simple, can be carried out in apparatus commonly used in the field of chemical processes and can be controlled simply by regulating the amount of reagents introduced in the course of the reaction.
A further object is to provide a very flexible process which permits to obtain, by varying the operative modalities, a wide range of products with different structural characteristics.
Still another object is to provide a process which results in peroxidic perfluoropolyethers having a very low ratio of --COF end groups to non-functional end groups.
These and still further objects are achieved by the process according to the present invention for preparing peroxidic perfluoropolyethers containing perfluoroalkylenoxy units (CF.sub.2 --CF.sub.2 O) and (CF.sub.2 O).
This process is characterized in that tetrafluoroethylene is reacted with oxygen in a solvent at a temperature not exceeding 50.degree. C. and in the presence of one or more compounds having one or more F--X bonds, in which X is selected from the group consisting of F, O and Cl.
In particular, when X is oxygen, said compound is an oxygen fluoride or an organic compound containing one or more fluoroxy groups. More usually, it is a perhalogenated alkyl or alkylene compound (the halogen atoms of which being F atoms or F and Cl atoms), containing one or more fluoroxy groups and, optionally, one or more heteroatoms, in particular oxygen atoms.
Said compound usually contains one or two fluoroxy groups. Preferably it is a perfluorinated compound; when it
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Marchionni Giuseppe
Marraccini Antonio
Sianesi Dario
Ausimont S.r.l.
Delacroix-Muriheid C.
Niebling John
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