DE929791C - Process for the preparation of gel-forming organophilic clays - Google Patents

Description

Process for the preparation of gel-forming organophilic clays The invention relates to a method for producing modified organophilic clays which are dispersible in organic solvents and form gels, pastes and therein highly viscous liquids swell.

Naturally occurring clays with base-exchanging properties are usually salts of a complex silicate with inorganic bases such as alkalis and alkaline earths. Certain colloidal clays, such as B. Bentonite, swell when they are placed in water to multiples of their dry volume and form at the same time gels of great viscosity. When the dispersed clay particles are a Clays, for example of the bentonite type, treated with certain organic compounds compounds of clays with organic compounds, which are organophilic, are formed are, d. H. easily swell in organic, predominantly liquid compounds and often form usable gels, pastes or highly viscous liquids.

It is already known that a clay of the type of bentonite with an organic compound containing an organic base, reacted can be, wherein the inorganic cation of the clay by the substituted cation the organic compound is replaced. The previously known, converted in this way Clays were compounds of clay with strong, titratable organic bases, and their nature made them suitable for use as medicinal preparations for treatment of the intestine and the Guts suitable. In this way, z. B. a strychnine bentonite has been produced. These previously known, through organic However, compounds converted clays show in organic liquids, such as. B. nitrobenzene, zeine noticeable swellability.

The aim of the invention is to create a method by natural or synthetic clays by treating with organic compounds can be converted in such a way that they swell strongly in organic solvents and form gels, pastes or highly viscous liquids. The surface of the received modified clays are to a large extent with aliphatic or carbocyclic organic radicals that are firmly attached to the clay. It will be on in this way a highly organophilic modified clay is obtained, which is characterized by that a large part of the surface of the clay particles with organic alkyl and aryl radicals which is covered with the clay by the ion exchange by means of an onium base are connected. An onium compound in the sense of the definition in Hackh's Chemical Dictionary, 2nd Edition, an organic compound of the type R X H, understood, which is an isologue of ammonium and the element X in its contains the highest valency, so with pentavalent X an ammonium, phosphonium, Arsonium and stibonium compounds, with tetravalent X an oxonium, sulfonium, Selenonium and stannonium compounds and with trivalent X an iodonium compound.

The exchange of the cation by the substituted onium compound is carried out to such an extent that 2 g of the onium clay obtained in one organic liquid, such as nitrobenzene, swell to at least 20 ml. Preferably becomes an onium radical with a straight chain and a linear extent of at least about 15 angstrom units and / or a surface area of at least about 70 square angstrom units are used. The onium radical can have a substituent with at least 10 carbon atoms in a straight chain.

According to an exemplary embodiment of the invention, the Modified clay can be produced by adding the organic base an acid, for example aqueous hydrochloric acid or aqueous acetic acid, into the Salt form is converted, whereupon the oniumyerbond formed during this salt formation is added to the clay dispersed in the aqueous medium. Generally will the onium compounds in the ratio of 100 milliequivalents per 100 g of clay or also used in relation to mutual saturation. However, it is according to the invention it is not necessary that in the resulting modified clay the inorganic Cation is completely replaced by the onium base. In most of the cases it occurs rapid and complete flocculation, whereupon the precipitated compounds washed, filtered off and usually dried by means of air passed through; The replacement of the inorganic cations of the clay by organic bases is generally used viewed as a base exchange reaction.

The clays with base-exchanging properties and the ability to to swell in water are suitable as starting materials. Particularly suitable is bentonite, which swells strongly in water, as it consists of very small Particle exists and has high base exchange properties.

The term clay used in the following also includes montmorillonite, namely sodium, potassium, lithium and other bentonites, especially those of the Wyoming and South Dakota types, also magnesian umbentonite, sometimes hectorite or Sapomt is called, finally nontronite and similar synthetic base-exchange agents Fabrics. The ability of the clays mentioned to exchange the cation is within the range from about 40 to 120 milliequivalents per 100 grams of clay.

The modified clays that swell up in organic liquids, which contain onium bases with alkyl and aryl radicals can be used to test the Efficacy of the organic cation can be studied in the following way: 2 g des powdered clay product connected with the onium base is transformed into an organic one Solvents such as B. nitrobenzene, introduced and left for up to 24 hours. Depending on the degree of wettability and the speed with which the maximum Gel volume is reached, the sample now takes different amounts of the organic Liquid swells up to a paste-like form with a visible increase in volume or highly viscous liquid system. This investigation procedure for examination of the organophilic C; character; the modified tone depends on several factors from, among other things, on the extent to which the surface of the clay particles with organic matter is covered, the degree of saturation of the clay by organic Cations, the type of organic bases, the dissolving liquid (namely polar or non-polar etc.).

Typical comparison values obtained using the method described above of a dodecylammonium bentonite, in which the ratio of onium compound to bentonite have been varied, are summarized in the following table, namely that is Swells of a 2 g sample in nitrobenzene expressed in milliliters.

Milliequivalents of onium for each ioogBentonite .. 50 75 100 I25 I50 200 Swelling in nitrobenzene in milliliters ....... 23 43 88 65 56 37 The effect of various, radicals bound on the surface of the clay particles on the degree of swelling of a 2 g sample in nitrobenzene is shown in the following table: In each Traps were 100 g of Wyoming bentonite with 100 milliequivalents of an onium compound from a primary amine reacted with an alkyl radical was substituted with a straight chain and the specified number of carbon atoms.

Number of carbon atoms in the chain of the amine substituent. 4 6 8 10 I2 I8 Swelling in nitrobenzene in milliliters ..., ... ... 5 6 8 36 88 88 Aus These values show that the modified clay, its onium compound in the alkyl substituent has fewer than 10 carbon atoms in the straight chain, in an organic Liquid does not gain any essential gel properties through swelling. As soon as however the number of carbon atoms in the straight chain exceeds 10 is one detect a significant increase in swelling. According to the invention are therefore the Tone and the onium compound chosen so that the resulting modified tone has a pronounced gel character, namely so that a 2 g sample in z. B. Nitrobenzene swells to at least 20 ml.

It is noted that the amine is initially in acidic aqueous solution is converted into the corresponding onium compound or into the onium salt before it is reacted with the clay with an exchange of bases. Although according to the invention in particular amines are used which have 10 or more carbon atoms in one have straight aliphatic chain, the invention extends beyond it also on the use of other compounds in the onium form, which are suitable to react with the clays to form onium clays, 2g of which in an organic Swell liquid such as nitrobenzene to at least 20 ml.

If a gel is to be produced that is free of particles with Is abrasive action, so it is advantageous in a dilute aqueous suspension the clay to allow the impurities to settle or by centrifugation to remove.

If the impurities present in the clay are harmless, then it can it is also sufficient to simply add the dry clay to a solution that contains enough substituted onium compounds to be more or less complete reacting with the clay by exchanging bases.

Example I 2750 g of Wyoming bentonite are suspended in 70 l of water. The resulting suspension is left to stand for 2 hours so that all of it does not come off Clay can settle existing impurities. About IoO / o of the bentonite weight are discarded by decanting. 150 g of glacial acetic acid become 663 g of octadecadienylamine added, and the formed onium salt is dissolved in 4 l of warm water. To the addition of the onium salt solution to the bentonite mixture causes flocculation, and the precipitate is filtered, washed, dried and pulverized. The received Octadecadienylammonium bentonite compound dispersed in numerous organic Liquids with the formation of real gels.

Example 2 150 g of glacial acetic acid are added to 464 g of dodecylamine and the obtained dodecylammonium acetate salt dissolved in 4 l of warm water. 2750 g of Wyoming type bentonite are dispersed in 70 l of water. The mixture is left Stand for 2 hours so that the clay impurities are dispersed from the Discontinue the clay suspension. The dodecylammonium acetate solution then becomes the dispersed one Bentonite mixture added, whereupon the onium bentonite flocculates. The precipitation is filtered off, washed, dried and pulverized.

The modified clay product obtained in this way is extremely organophilic. If 150 g of the dodecylammonium bentonite are added to IOQO g of tricresyl phosphate, so it swells up in it, and a translucent brown gel is formed, which after After passing through a three-roller mill, a paste of the consistency of petroleum jelly supplies.

This paste has a flash point of around 2500 C and loses up to about 4000 not their liquid phase. The material is therefore used as a lubricant very suitable at high temperatures. It can also be used as a sealant in ignition devices of aircraft engines are used, since even at voltages of 31,000 volts no flashover occurs. After further dilution with tricresyl phosphate, the Fabric because of its flatness between - 40 and + 3500 C. Viscosity curve as hydraulic Liquid can be used.

Example 3 Triphenyllaurylphosphonium bromide is obtained by heating a Mix equivalent amounts of triphenylphosphine and lauryl bromide on the reflux condenser won. After six hours of heating, the reaction mixture is cooled and poured into Alcohol dissolved. To a dispersion of 50 g Wyoming bentonite in I 1 water an alcoholic solution of 0.05 mol of the phosphonium base was added.

After the pH of the slightly basic dispersion has been diluted by adding Hydrochloric acid is brought to about 4, the triphenyllaurylphosphonium bentonite flocculates off, is filtered off, washed, dried and ground. The connection swells in numerous organic liquids with pronounced gel formation.

Example 4 0.1 mol of didodecylethylsulfonium bromide are dissolved in 1 liter of water dispersed and with stirring with 400 ccm of a 2.50 / o aqueous suspension of Wyoming bentonite mixed. After standing for one hour, it is filtered off and dried and ground. The so obtained Didodecyläthylsulfonium- bentonite compound disperses quickly in numerous organic liquids.

Example 5 The method according to Example 4 is modified in the manner that 0.1 moles of decyltriphenylarsonium chloride instead of didodecylethylsulfonium bromide is used.

Example 6 The method according to Example 4 is modified in the manner that 0.1 mol of decyltriphenylstibonium chloride instead of didodecylethylsulfonium bromide is used.

Example 7 The method according to Example 4 is modified in the manner that 0.1 mol of didodecyl-y-pyrone is used in place of didodecylethylsulfonium bromide will.

Example 8 The method according to Example 4 is modified in such a way that that O, I mol didodecylethyltelluronium chloride instead of didodecylethylsulfonium bromide is used.

Any of those prepared according to the procedures described in the examples Clay products forms a pronounced one in numerous organic liquids Gel by swelling 2 g of the clay product in nitrobenzene to 20 or more milliliters.

In all of the exemplary embodiments described, the onium base contained a substituent with at least 10 carbon atoms in a straight chain.

Claims (6)

PATENT CLAIMS: I. Process for preparing gel-forming organophils Clays from a raw material with an original base exchange capacity of at least 25 milliequivalents per - 100 g, characterized in that in the clay or in a similar synthetic substance, for example in bentonite, hectorite, Nontronite and montmorillonite, the cation substituted by an onium radical of the type of ammonium, phosphonium, arsonium, stibonium, oxonium, sulfonium, Telluronium compounds are replaced to such an extent that they are replaced by the anion of the clay form an onium clay, of which 2 g in an organic liquid, like nitrobenzene, swell to at least 20 ml. 2. The method according to claim, characterized in that an onium radical with a straight chain with a linear extent of at least about 15 Angstrom units is used. 3. The method according to claim I, characterized in that an onium radical with a straight chain with a surface area of at least about 70 square angstrom units is used. 4. The method according to claim I, characterized in that an onium radical is used with at least 10 carbon atoms in a straight chain. 5. The method according to claims I to 4, characterized in that that the clay in the ratio of 100 g of clay to at least 50 milliequivalents of onium base is made to react. 6. The method according to claim I, characterized in that an onium compound, those having an organic aliphatic radical of at least 12 carbon atoms is substituted in a straight chain, is reacted.