WO1997014701A1

WO1997014701A1 - Silicon peroxide compounds

Info

Publication number: WO1997014701A1
Application number: PCT/EP1996/004486
Authority: WO
Inventors: Karsten KÖNIGSTEIN
Original assignee: Koenigstein Karsten
Priority date: 1995-10-17
Filing date: 1996-10-16
Publication date: 1997-04-24
Also published as: AU7293396A

Abstract

The invention concerns alkyl and/or arylsilicon peroxide compounds and silicon peroxide obtained by reacting alkoxysilanes and/or aryloxysilanes and in particular tetraalkoxysilanes and/or tetraaryloxysilanes. The invention also concerns a process for preparing these compounds.

Description

Silicon peroxide compounds

The invention relates to alkyl and / or aryl silicon peroxide and silicon peroxide and a process for their preparation.

Methods for producing silicon peroxide compounds are known from US Pat. Nos. 3700712 and 3843 703, in which a dimethylaminosilicon compound or a silazane compound is reacted with a hydrogen peroxide compound.

S Kraus and C. Oettner report in Z. anorg u allg Chem. 222 (1935), pp. 345 to 370 about new investigations about "Persilikate". For example, on pages 351/352 the production of "per silicic acids" with different water contents is reported . Dehydration is described starting from a peracid of the formula SiO ₂ H ₂ O ₂ 2H ₂ O. It is stated that the addition of hydrogen peroxide was easily perform on silica, was carefully evaporated in which precipitated from water glass silicic acid of the composition SιO ₂ ^• H ₂ O with 30% hydrogen peroxide solution ιger in vacuo. By decomposing the above-mentioned compound, 1 mol of water and a further mol of water could initially be split off, the analysis of the composition subsequently yielding SiO ₂ H ₂ O ₂ .

After the loss of two molecules of water, as the experiments by these authors showed, oxygen and water split off in the ratio of the hydrogen peroxide. No specific pressure was established, but the further decay was followed by suction at the same pressure and at a constant temperature , a course emerged which led the authors to conclude that the compound SiO ₂ 1/2 H ₂ O _{2 existed} .

Regarding the silicas, it is further stated on page 356 that these are hydrogen peroxide addition products on SiO ₂ . that the compounds are decomposable and give off active oxygen and water in the air as well as in the absence of air, while in turn they should be stable in solution because the silica which is formed in part is said to act as a stabilizer on the hydrogen peroxide.

The analytical data, in particular FIG. 3 on page 369 of the document, show that this is an additive compound of hydrogen peroxide on silicon dioxide.

DE-OS 20 13 762 discloses a method and an agent for oxidative hair treatment using solid products containing H ₂ O ₂ and Si0 ₂ .

The problem of the present invention consists in the provision of silicon peroxide compounds and silicon peroxide, the application possibilities of which are evident in many areas of chemical engineering.

With the help of the present invention, alkyl and / or aryl silicon peroxide compounds and silicon peroxide can be produced by reacting alkoxysilanes and / or aryloxysilanes with hydrogen peroxide.

In a first embodiment, the invention provides alkyl and / or aryl silicon peroxide compounds of the general formula (I)

Si _x O _4x R _4x.y (I),

obtainable by reacting alkoxysilanes and / or aryloxysilanes with hydrogen peroxide, where R _{x is} one or more straight-chain or branched, saturated mono- and / or polyunsaturated alkyl radicals having 1 to 10 carbon atoms or one or more aryl radicals having 6 to 12 cabbages Substance atoms and x and y each for an integer with x greater than or equal to 1 and y equal to 2, 3 or 4 times x. Another embodiment includes the provision of silicon peroxide obtainable by reacting tetraalkoxysilanes and / or tetraaryloxysilanes with hydrogen peroxide.

The glassy amorphous substance of silicon peroxide is stable in storage for months at room temperature and has an IR spectrum that is shown in FIG. 1.

The IR spectrum of FIG. 1 shows no CH valence vibrations in the range from 2900 to 3000 cm ^-1 , which suggests that all alcohol groups or phenol groups of the alkoxysilanes or aryloxysilanes have been completely exchanged.

The band at approximately 3400 cm ^"1 can be assigned to the OH valence vibrations. A very strong further band is in the range of 1080 cm ^{" 1} and should possibly be assigned to a Si-O valence vibration. This strong band has a pronounced shoulder in the range from 1100 to 1200 cm ^"1. Other characteristic vibrations are recognizable in the range from about 935 cm ^{" 1} (possible interpretation: Si-O-Si valence vibration), about 800 cm ^"1 ( possible interpretation: OH deformation vibration) and about 460 cm ^'1 (possible interpretation: Si-O deformation vibration).

2 shows an IR spectrum of the additive compound of SiO ₂ to H ₂ O ₂ according to the above-mentioned prior art. The lack of a shoulder in the range from 1100 to 1200 cm ^'1 and the lack of a band at 935 cm ^"1 indicate that the attachment compound of the above-mentioned prior art does not correspond to the subject matter of the present invention.

From B. Wiecken and S. Wübbold-Weber; Journal Seifen, Öle, Fette, Wachsen, (1995) 121, p. 428 are studies on boron, which is widely used as a bleaching agent in the production of detergents, in drinking water in the Federal Republic Germany known. After that, the boron must also be viewed critically and checked for its ecological relevance and compatibility.

With the help of the present invention, an ecologically and economically sensible substitute is created here. The silicon peroxide according to the invention is simple and inexpensive to produce from easily accessible raw materials.

When used in detergents, the degradation products are ecologically harmless substances that, in particular compared to borates, no longer have an acid function.

It is assumed that the silicon peroxide according to the invention already has an ion exchange capacity, since lattice sites are released by the exchange of oxygen. The silicon peroxide according to the invention can therefore also be used previously ion exchangers such as layered silicates; For example, partially or completely replace in detergent formulations.

Compared to the known addition compounds of Si0 ₂ to H ₂ 0 ₂ , the silicon peroxide according to the invention is characterized by increased thermal stability in both the solid and the moist state. The silicon peroxide according to the invention also has less tendency to exchange hydrogen peroxide with water.

In addition, stabilization with peroxide stabilizers known per se is possible. Particular stabilizing effects could be achieved with Na ₂ Sn (OH) ₆ , alkali metal phosphates, in particular Na ₃ PO ₄ or Na ₂ H ₂ P ₂ O ₇ , phenacetin, 8-oxyquinols and with di-piezoic acid.

A preferred embodiment of the present invention consists in the process for the production of silicon peroxide by reacting alkoxysilanes and / or aryloxysilanes with hydrogen peroxide. For the purposes of the present invention, particular preference is given to using alkoxysilanes and / or aryloxysilanes of the general formula II RiO OR ₃

R ₂ 0 X OR ₄

where R _L R ₂ , R ₃ or R ₄ each represent the same or different for a straight-chain or branched, saturated, mono- and / or polyunsaturated alkyl radical with 1 to 10 carbon atoms or an aromatic hydrocarbon radical with 6 to 12 carbon atoms. The type of alkyl or aryl radicals is of minor importance, since these radicals are completely removed from the product in the form of the corresponding alcohols / phenols or naphthols. It is thus also possible to use silanes in which radicals R ₁ , R ₂ , R ₃ and R ₄ are different from one another.

A large number of the aforementioned silanes are commercially available. Accordingly, the tetraalkoxysilanes are preferably selected from tetra methoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-i-propoxysilane, tetra-n-butoxysilane, tetrakis (2-ethylbutoxy) silane and tetrakis (2-ethylhexoxy) silane.

Likewise preferred tetraaryloxysilane is tetraphenoxysilane.

When using unsaturated tetraalkoxysilanes or tetraaryloxysilanes, attention should be paid to the possible epoxidation of the double bond (s) by exposure to hydrogen peroxide if the starting alcohols are to be used again. If 1 to 3 of the alkoxy radicals or aryloxy radicals are replaced by the corresponding alkyl radicals or aryl radicals, the corresponding alkyl silicon peroxides or aryl silicon peroxides are available.

Hydrogen peroxide for the purposes of the present invention can be used in aqueous solution and in anhydrous form. However, since working with high-percentage hydrogen peroxide solutions is associated with extraordinary dangers, usually lower levels of hydrogen peroxide are chosen. A content of 10 is particularly preferred for the purposes of the present invention to 90% by weight, most preferably 30 to 50% by weight, of hydrogen peroxide in aqueous solution.

The process for reacting the alkoxysilanes and / or aryloxysilanes and in particular the tetraalkoxysilanes and / or tetraaryloxysilanes with hydrogen peroxide can be implemented most simply by reacting the silanes with an excess of molar amount, in particular a 2 to 10-fold molar excess of hydrogen peroxide. It is also possible to obtain the silicon peroxide compound or silicon peroxide according to the invention even at room temperature, optionally with cooling with a suitable coolant, in particular over a period of 12 hours to 3 days with stirring or over a period of 1 day to 10 days without stirring.

A gel-like consistency is formed in the production, particularly of silicon peroxide, from which the supernatant liquid is preferably separated off by decanting. Following this, it is particularly preferred according to the invention to dry to constant weight at room temperature. Depending on the grain size, a white to transparent, glass-like substance is obtained which has up to 32% cleavable peroxide groups.

The silicon peroxide compounds according to the invention and the silicon peroxide can be used for a number of industrial chemically and technically interesting purposes. The first priority here is the replacement of perborates as bleaching agents in conventional detergent compositions. It is also possible to replace metal peroxides in explosive mixtures or primers with the aid of the silicon peroxide compound or silicon peroxide according to the invention. Because of the hydrogen peroxide elimination, it can also be used as a free-radical initiator in plastics production, in particular in free-radically initiated polymerization. Further uses include, for example, the replacement of layered silicates, the use in epoxy production, for example the production of e-caprolactone, as a PVC stabilizer, as an oxidizing agent and preservative, as a food additive, additive in pharmaceuticals, in waste water treatment autoxidation, in cleaning agents, in disinfectants and as a direct medical application in oxygen baths or hair bleaches.

A direct reaction of tetrachlorosilane with hydrogen peroxide was not possible because the resulting HCl immediately destroyed the peroxide formed. However, the above-mentioned alkoxysilanes or arylsilanes do not necessarily have to be used in material form, but can, if appropriate, also be produced in situ.

Embodiment

1 mol (204 g) tetraethoxysilane was mixed with a 2-fold excess of hydrogen peroxide (35% aqueous solution, 68 g). The substances were allowed to react with one another with constant stirring within one day. A gel was obtained which still contained small amounts of excess liquid which were filtered off or decanted. The gel was then dried to constant weight at room temperature in a desiccator using Blaugel. The white substance contained 32% by weight of cleavable peroxide groups.

An infrared spectrum was recorded from the peroxide glass, which is shown in FIG. 1.

Example 2

Analogously to Example 1, 1 mol (204 g) of tetraethoxysilane was reacted with a 10-fold excess of hydrogen peroxide (35% strength aqueous solution, 340 g) without stirring within one week. A gel was obtained which contained excess liquid which was filtered off / decanted. The gel obtained was dried to constant weight at room temperature. The transparent glassy substance contained 32% by weight of cleavable peroxide groups.

The peroxide glasses produced according to Example 1 and Example 2 were titrated. For this purpose, 50 mg of peroxide glass were suspended in 10 ml of water, acidified with 3 drops of concentrated sulfuric acid and 30 ml of 3.3% (0.2 mol / l) potassium iodide solution were added. After 15 minutes, titration was carried out with 0.1 N (0.1 mol / l) sodium thiosulfate standard solution to a weak yellow color, adding a drop of starch solution and titrating until the color changed (1 ml of 0.1 N sodium thiosulfate solution corresponded to 1 , 7007 mg H ₂ O ₂ ).

3 shows a differential thermogram of the silicon peroxide according to Example 1, from which it can be seen that a continuous elimination of hydrogen peroxide can be observed here. while no water is being split off. The mass spectrogram attached as FIG. 4 only shows peaks in the range of 32 m / z, from which it follows that the organic residues and water (water of crystallization) have been completely removed.

Example 3

Analogously to Example 1, 47 ml of tetraethoxysilane were reacted with 65 ml of 62% by weight hydrogen peroxide with ice cooling and protective gas (nitrogen). After drying as in Example 1, the first titration gave 63% peroxide after 14 days. Possible hydrogen peroxide inclusions cannot be ruled out, since the theoretical upper limit of the peroxide content is 35%.

Claims

claims

Alkyl and / or aryl silicon peroxide compounds of the general formula (I)

Si _x O _4x R _4x.y (I),

obtainable by reacting alkoxysilanes and / or aryloxysilanes with hydrogen peroxide, where R _{v is} one or more straight-chain or branched, saturated, mono- and / or polyunsaturated alkyl radicals having 1 to 10 carbon atoms or one or more aryl radicals having 6 to 12 Carbon atoms and x and y each for an integer with x greater than or equal to 1 and y equal to 2, 3, or 4 times x.

Silicon peroxide can be obtained by reacting tetraalkoxysilanes and / or tetraaryloxysilanes with hydrogen peroxide.

A process for the preparation of alkyl and / or aryl silicon peroxide compounds according to claim 1, by reacting alkyl alkyl oxysilanes, aryl alkoxysilanes, alkyl alkoxysilanes and / or aryl aryloxysilanes with hydrogen peroxide.

Process for the production of silicon peroxide by reacting tetraalkoxysilanes and / or tetraaryloxysilanes with hydrogen peroxide. Process according to Claim 4, characterized in that tetraalkoxysilanes and / or tetraaryloxysilanes of the general formula (II)

is used, wherein R ^ R ₂ , R ₃ or R ₄ each represent the same or different for a straight-chain or branched saturated mono- and / or polyunsaturated alkyl radical having 1 to 10 carbon atoms or an aromatic hydrocarbon radical having 6 to 12 carbon atoms

Process according to Claim 4, characterized in that the tetraalkoxysilanes are selected from tetramethoxysilane, tetra-ethoxysilane, tetra-n-propoxysilane, tetra-i-propoxysilane, tetra-n-butoxysilane, tetra-kιs (2-ethylbutoxy) sιlan and tetrakιs ( 2-ethylhexoxy) sιlan

A method according to claim 4, characterized in that the tetraaryloxysilanes are selected from tetraphenoxysilane

Process according to one or more of claims 3 to 7, characterized in that aqueous solutions of hydrogen peroxide, in particular with a content of 10 to 90% by weight hydrogen peroxide, are used

Process according to one or more of claims 3 to 8, characterized in that alkoxysilanes and / or aryloxysilanes and in particular tetraalkoxysilanes and / or tetraaryloxysilanes with a molar excess, in particular a 2- to 10-fold Excess amount of hydrogen peroxide, in particular at room temperature, optionally with cooling, in particular in the course of 12 hours to 3 days with stirring or in the course of one day to 10 days without stirring.

10. The method according to one or more of claims 3 to 9, characterized in that after the reaction, supernatant liquid is separated off and the gel obtained is dried to constant weight, in particular at room temperature.

11. Use of alkyl and / or aryl silicon peroxide compounds and silicon peroxide according to one or more of claims 1 to 10, as a bleaching agent in detergent compositions, in explosive mixtures, in primers, as a radical initiator in plastics production, in particular in free-radically initiated polymerization, as Replacement of layered silicates, in the production of epoxies, in particular the production of e-caprolactone, as a PVC stabilizer, as an oxidizing agent and preservative, as a food additive, in autoxidation, in cleaning agents, in disinfectants and as a direct medical application in oxygen baths or. hair bleach.