ES2385672T3 - Process for preparing organically modified double stratified hydroxide - Google Patents

Abstract

The invention relates to a process for preparing an organically modified layered double hydroxide having a distance between the individual layers of the layered double hydroxide of above 1.5 nm and comprising an organic anion as charge-balancing anion, the process comprising the steps of: (a) preparing a precursor suspension comprising a divalent metal ion source and a trivalent metal ion source;(b) solvothermally treating the precursor suspension to obtain the layered double hydroxide, wherein an organic anion is added before or during the formation of the layered double hydroxide of step (b), or following the formation of the layered double hydroxide, so as to obtain the organically modified layered double hydroxide, with the proviso that deoxycholic acid is not the sole organic anion.; The invention further pertains to a process for preparing an organically modified layered double hydroxide having a distance between the individual layers of the layered double hydroxide of above 1.5 nm and comprising an organic anion as charge-balancing anion, the process comprising the steps of: (a) preparing a precursor suspension comprising a divalent metal ion source and a trivalent metal ion source; (b) thermally treating the precursor suspension to obtain the layered double hydroxide, wherein an organic anion is added before or during the formation of the layered double hydroxide of step (b), or following the formation of the layered double hydroxide, so as to obtain the organically modified layered double hydroxide, with the proviso that in step a) the trivalent metal ion source is not reacted with the organic anion at a temperature of between 60 and 85 DEG C for 4 to 8 hours prior to the addition of the divalent metal ion source and step b) is subsequently carried out at a temperature of 90 to 95 DEG C for 4 to 8 hours.

Description

Process for preparing organically modified double stratified hydroxide.

The invention relates to a process for preparing organically modified double stratified hydroxides.

Such processes are known in the art.

WO 99/35185 describes a process for preparing organically modified double stratified hydroxides (LDHs) where the organic anion is introduced into the LDH by ion exchange. The ion exchange is carried out by suspending the LDH in water, after which the pH of the suspension is reduced to a value lower than 4. Next, the organic anions are added to the suspension and the pH is adjusted to a value. which exceeds 8. This process is quite complex and generally produces a residual current containing salts.

WO 00/09599 describes the preparation of LDH comprising organic anions as intercalation anions. These modified LDHs can be prepared in various ways, making use of the salts of divalent and trivalent metal ions, such as the magnesium chloride and aluminum or sodium aluminate salts. The processes described in WO 00/09599 describe salts that will at least partially end up in the residual stream, which is undesirable. It should be further noted that the salts used in these processes are relatively expensive.

As a whole, the economics of the processes described above show a need for processes that are more economically attractive and more environmentally friendly.

For this reason, it is an object of the present invention to provide a simpler and more environmentally friendly process for preparing organically modified double stratified hydroxides.

This object is achieved with a process for preparing an organically modified double stratified hydroxide having a distance between the individual layers of the stratified double hydroxide greater than 1.5 nm and comprising an organic anion as a charge balancing anion, the process comprising The steps of:

(to)

preparing a precursor suspension comprising a source of divalent metal ions and a source of trivalent metal ions;

(b)

subject the precursor suspension to solvothermic treatment in order to obtain the double stratified hydroxide,

wherein an organic anion is added before or during the formation of the double stratified hydroxide of step (b), or after the formation of the double stratified hydroxide, in order to obtain the organically modified double stratified hydroxide, wherein the source of metal ions divalent and / or the source of trivalent metal ions is ground (n) before step (b), and where water is used as a suspension medium, with the proviso that deoxycholic acid is not the only organic anion.

This object is also achieved with a process for the preparation of an organically modified double stratified hydroxide having a distance between the individual layers of the stratified double hydroxide greater than 1.5 nm and comprising an organic anion as a charge balancing anion, comprising the process the steps of:

(to)

preparing a precursor suspension comprising a source of divalent metal ions and a source of trivalent metal ions;

(b)

heat treat the precursor suspension in order to obtain the double stratified hydroxide,

wherein an organic anion is added before or during the formation of the double stratified hydroxide of step (b), or after the formation of the double stratified hydroxide, in order to obtain the organically modified double stratified hydroxide, wherein the source of metal ions divalent and / or the source of trivalent metal ions is ground (n) before step (b), and where water is used as a suspension medium, with the proviso that in step (a) the source of trivalent metal ions it is not reacted with the organic anion at a temperature between 60 and 85 ° C for 4 to 8 hours before the addition of the source of trivalent metal ions and step (b) is subsequently carried out at a temperature of 90 to 95 ° C for 4 to 8 hours.

The sources of divalent metal ions and the source of trivalent metal ions used in the processes of the present invention are not salts of these metal ions, in particular these sources are not chloride or perchlorate salts of the divalent and trivalent metal ions, or if the Trivalent metal ion is aluminum, aluminates. It should be noted that these sources can be partially dissolved in the suspension medium.

The sources of divalent and trivalent metal ions are generally oxides or hydroxides of the divalent or trivalent metal ions. Examples of divalent metal ions are Zn2 +, Mn2 +, Ni2 +, Co2 +, Fe2 +, Cu2 +, Sn2 +, Ba2 +, Ca2 +, and Mg2 +. Examples of trivalent metal ions are Al3 +, Cr3 +, Fe3 +, Co3 +, Mn3 +, Ni3 +, Ce3 +, and Ga3 +. The use of three or more different metal ions in the double stratified hydroxide prepared by the process of the invention is also contemplated. Of these metal ions, the combination of Mg2 + and / or Zn2 + and Al3 + is preferred. Examples of suitable sources of magnesium include magnesium oxide, magnesium hydroxide, magnesium hydroxycarbonate, magnesium bicarbonate, dolomite, and sepiolite. Magnesium oxide is preferred. A combination of two or more sources of magnesium is also contemplated. The aluminum source is typically a hydroxide or an aluminum oxide. Examples of said aluminum source are aluminum trihydroxide, such as gibbsite and bayerite, aluminum oxohydroxides such as boehmite, diasporo or goethite, and transition aluminas, which are known to those skilled in the art.

The use of the sources of divalent metal ions and previous trivalent metal ions in the process of the invention provides a process that is more environmentally friendly, given that a considerably smaller amount of salts (if any) remains in the resulting residual current of process. In addition, the sources of divalent and trivalent metal ions, and in particular the sources of magnesium and aluminum, are generally less expensive than the corresponding salts commonly used in the production of double stratified hydroxides. Additionally, the process of the invention is generally simpler, since it requires fewer steps and / or does not require any post-treatment of the residual current. Moreover, these processes can be carried out in a much shorter time, which in turn can lead to a higher production capacity of organically modified double stratified hydroxide compared to conventional processes.

In one embodiment of the process of the invention, the source of divalent metal ions and / or the source of trivalent metal ions is activated prior to the thermal or solvothermic treatment of the suspension comprising both sources. The term "activated" refers to the activation of the sources of divalent and / or trivalent metal ions, thereby increasing their reactivity in the process; said activation can be carried out for example by dry or wet grinding and / or by acid treatment. An additional advantage of activating metal ion sources is that significantly smaller amounts of impurities are formed during the process, such as brucite or gibbsite. The reduction or absence of such impurities in the product obtained with this process offers the additional advantage that the use of the product in polymer matrices can lead to the resulting composite material having improved dynamic and / or mechanical properties.

The organically modified double stratified hydroxides prepared with the process of the invention have a distance between the individual layers greater than 1.5 nm. This provides advantages in the use of these organically modified double stratified hydroxides, e.g. if used in polymer matrices. In polymer matrices (eg, in nanocomposite materials or coating compositions) the greater interlayer distance makes the double stratified hydroxides of the invention easily processable in the polymer matrix, and additionally allows easy de-stratification and / or hydroxide exfoliation. double stratified, resulting in a mixture of the modified double stratified hydroxide and the polymer matrix with improved physical properties. The distance between the layers in an LDH according to the invention is at least 1.5 nm, more preferably at least 1.6 nm, even more preferably at least 1.8 nm, and most preferably at least 2 nm. The distance between the individual layers can be determined using X-ray diffraction and electron transmission microscopy (TEM), as indicated below. The sources of divalent and / or trivalent metal ions, and in particular the sources of aluminum and / or magnesium, are ground before step (b). In the processes of the invention, the sources of divalent and / or trivalent metal ions generally have a d50 value of less than 20 µm and a d90 value of less than 50 µm. Preferably, the value d50 is less than 15 µm and the value d90 is less than 40 µm, the d50 value being more preferably less than 10 µm and the d90 value less than 30 µm, the d50 value being even more preferably less than 8 µm and the d90 value less than 20 µm, and very preferably the d50 value is less than 6 µm and the d90 value is less than 10 µm. The particle size distribution can be determined using methods known to those skilled in the art, e.g. laser diffraction according to DIN 13320. This grinding step allows the formation of the double stratified hydroxide to proceed more rapidly. Additionally, said step can reduce the amount of impurities such as gibbsite or brucite if the sources of divalent and trivalent metal ions are sources of magnesium and aluminum.

In the context of the present application, the terms "heat treatment" and "thermally" refer to the treatment of the precursor suspension at a temperature of 30 ° C to the boiling point of the precursor suspension at atmospheric pressure. If the suspension medium is water, the temperature of the heat treatment is generally from 30 ° C to 100 ° C, preferably from 40 ° C to 95 ° C, and more preferably from 50 ° C to 90 ° C.

Additionally, the terms "solvothermal treatment" and "solvothermally" refer to the treatment of the precursor suspension at a pressure greater than atmospheric pressure and at a temperature that is generally higher than the boiling point of the precursor suspension at atmospheric pressure. The pressure is generally 1 bar at 200 bars, preferably from 2 bars to 150 bars, and more preferably from 3 bars to 100 bars. If the suspension medium is water, the temperature is generally 100 ° C or higher, preferably from 100 ° C to 300 ° C, more preferably from 110 ° C to 250 ° C, and most preferably from 120 ° C to 200 ° C.

The process of the invention can be conducted in the absence of CO2 or any carbonate in the precursor suspension, in order to establish that no carbonate is incorporated in the double stratified hydroxide as a charge balancing anion. This further allows the organic anion to be incorporated into the double stratified hydroxide as a charge balancing anion.

In one embodiment of the invention, the organic anion is added to the precursor suspension before or while step (b) passes. Thus, the organically modified double stratified hydroxide is prepared in a single step, which generally makes the process simpler and faster, and therefore more economically attractive.

Alternatively, the organic anion is added after the formation of the double stratified hydroxide, in which case the double stratified hydroxide mainly comprises hydroxyl as a charge balancing anion. Said hydroxyl as a charge balancing anion can be easily exchanged for the organic anion.

Within the context of the present application, the term "charge balancing anion" refers to anions that compensate for electrostatic charge deficiencies of the crystalline sheets of LDH. Since the LDH typically has a stratified structure, the load balancing anions may be located in the intermediate layer, on the edge or on the outer surface of the stacked LDH layers. Such anions located in the intermediate layer of the stacked LDH layers are referred to as interleaving ions.

An LDH or stacked organo-clay of this type may also be de-stratified or exfoliated, e.g. in a polymer matrix. Within the context of the present specification, the term "de-stratification" is defined as a reduction in the degree of average stacking of the LDH particles by at least partial de-stratification of the LDH structure, thereby producing a material that significantly contains a number. significantly higher than individual LDH sheets per unit volume. The term "exfoliation" is defined as complete de-stratification, that is, the disappearance of the periodicity in the direction perpendicular to the LDH sheets, leading to a random dispersion of individual layers in a medium, without any stacking order remaining in absolute.

The swelling or expansion of LDHs, also called interleaving of LDHs, can be observed with X-ray diffraction (XRD), since the position of the basal reflections - that is, the reflections d (001) - is indicative of the distance between the layers, distance that increases with the interleaving.

The reduction of the average stacking degree can be observed as a widening, until disappearance, of the XRD reflections or by an increasing asymmetry of the basal reflections (001).

The characterization of complete de-stratification, that is, exfoliation, remains an analytical challenge, but can be deduced in general by the complete disappearance of reflections other than (hk0) from the original LDH.

The ordering of the layers and, therefore, the degree of de-stratification can be visualized further with transmission electron microscopy (TEM).

The LDH of the invention can be any LDH known to those skilled in the art. Typically, these LDHs are mineral LDHs that are susceptible to expansion or swelling. Such LDHs have a stratified structure comprising charged crystalline sheets (referred to also as individual LDH layers) with equilibrium anions of intercalated charges between them. The terms "expansion" and "swelling" within the context of the present application refer to an increase in the distance between the charged crystalline sheets. Expandable LDHs can swell in suitable solvents, e.g. water, and can be further expanded and modified by exchanging charge balancing ions with other (organic) charge balancing ions, a modification that is also known in the art as intercalation.

The organically modified double stratified hydroxides of the invention have a stratified structure corresponding to the general formula:

wherein M2 + is a divalent metal ion such as Zn2 +, Mn2 +, Ni2 +, Co2 +, Fe2 +, Cu2 +, Sn2 +, Ba2 +, Ca2 +, and Mg2 +, M3 + is a trivalent metal ion such as Al3 +, Cr3 +, Fe3 +, Co3 +, Mn3 +, Ni3 + , Ce3 +, and Ga3 +, having m and a value such that m / n = 1 to 10, and b has a value in the range of 0 to 10. X is an organic charge equilibrium anion that has at least 8 carbon atoms , or any other anion known to those skilled in the art, provided that at least a portion of the intercalation ions is the organic anion having at least 8 carbon atoms.

Examples of other anions known in the art include hydroxide, carbonate, bicarbonate, nitrate, chloride, bromide, sulphonate, sulfate, bisulfate, vanadates, tungstates, borates, phosphates, pillar forming anions such as HVO4-, V2O74-, HV2O124-, V3O93-, V10O286-, Mo7O246-, PW12O403-, B (OH) 4-, B4O5 (OH) 42-, [B3O3 (OH) 4] -, [B3O3 (OH) 5] 2-, HBO42-, HGaO32- , CrO42-, and Keggin ions.

The LDH of the invention includes hydrotalcite and anionic LDHs similar to hydrotalcite. Examples of such LDHs are hydrotalcite and materials similar to hydrotalcite, meixnerite, manasseite, pyroaurite, sjögrenite, stichtite, barberonite, takovite, reevesite, and deutelsite. A preferred LDH is hydrotalcite, which is an LDH that has a stratified structure corresponding to the general formula:

wherein m and n have a value such that m / n = 1 to 10, preferably 1 to 6, and b has a value in the range of 0 to 10, generally a value of 2 to 6, and often a value of approximately 4. X It is a charge balancing ion as defined above.

It is preferred that m / n have a value of 2 to 4, more particularly a value close to 3.

LDH can be found in any crystalline form known in the art, as described by Cavani et al. (CatalysisToday, 11 (1991), pp. 173-301) or by Bookin et al. (LDHs and LDH Minerals, (1993), vol. 41 (5), pp. 558564). If the LDH is a hydrotalcite, the hydrotalcite can be a polytype that has 3H1, 3H2, 3R1 or 3R2 stacking, for example.

The organic anion used in the process of the invention can be any organic anion that after intercalation provides an organically modified double stratified hydroxide according to the invention. The organic anion that can be conveniently used in the process can be derived from a salt or an acid from the organic anion. The use of a salt-derived organic anion such as an alkali metal stearate salt may be advantageous due to its greater solubility in the solvent compared to the corresponding acid-derived organic anion. Alternatively, the use of an organic acid-derived anion can be advantageous since saline ions will not be introduced into the residual stream, so the residual stream does not need additional treatments to remove the salt ions, making the process more economical and easier. .

The suitable organic anion in the process of the invention comprises 8 or more carbon atoms, with the proviso that the only organic anion present as a charge balancing anion is not terephthalate. Such organic anions having at least 8 carbon atoms include mono-, di- or polycarboxylates, sulfonates, phosphonates, and sulfates. Preferably, the organic anion comprises at least 10 carbon atoms, more preferably at least 12 carbon atoms, and the organic anion comprises a maximum of 1000 carbon atoms, preferably a maximum of 500 carbon atoms, more preferably a maximum of 100 carbon atoms , even more preferably at most 50 carbon atoms, and most preferably at most 20 carbon atoms. It is contemplated to use 2 or more organic anions, at least one of which has at least 8 carbon atoms, and the resulting LDH has an interlaminar distance of at least 1.5 nm; one of the other organic anions can therefore have less than 8 carbon atoms.

Organically modified LDHs comprising a single organic charge-balancing anion selected from the group consisting of acetate, succinate, benzoate, and terephthalate are less preferred, since they have an interlaminar distance less than 1.5 nm and as a rule do not exfoliate or easily de-stratify in polymer matrices, which makes these modified LDHs less suitable for use in nanocomposite materials or coating compositions, for example. Examples of such organically modified LDHs are given in US 5,728,366. Additionally, it is also less preferred that deoxycholic acid is present as the only organic anion, since it is too expensive. In addition, deoxycholic acid contains two hydroxyl groups, which can make exfoliation or de-stratification in a polymer matrix very difficult or even impossible. It is believed that this is caused by a kind of pillar forming behavior due to interaction between two or more interspersed deoxycholic acid anions or due to the interaction of a single deoxycholic acid anion with two different clay lamellae. In an embodiment of the present invention, it is desired that the deoxycholic acid not be used as a charge balancing anion.

Additionally, it is contemplated that the organic charge-balancing anion comprises one or more functional groups such as hydroxyl, amine, carboxylic acid, and vinyl. If such organically modified LDHs are used in polymer matrices, these functional groups can interact or react with the polymer.

Suitable examples of organic anions of the invention are monocarboxylic acids such as fatty acids and ions based on turpentine resin.

In one embodiment, the organic anion is a fatty acid or a salt thereof having 8 to 22 carbon atoms. A fatty acid of this type can be a saturated or unsaturated fatty acid. Suitable examples of such fatty acids are caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, decenoic acid, palmitoleic acid, oleic acid, linoleic acid, linolenic acid, and mixtures thereof.

In another embodiment of the present invention, the organic anion is turpentine resin or a salt thereof. Turpentine resin is derived from natural sources, is readily available, and is relatively inexpensive compared to synthetic organic anions. Typical examples of natural sources of turpentine resin are rubber turpentine resin, wood turpentine resin, and taloil turpentine resin. Turpentine resin is commonly a suspension of a wide variety of different isomers of monocarboxylic tricyclic resin acids usually containing the order of 20 carbon atoms. The tricyclic structures of the various resin acids differ mainly in the position of the double bonds. Typically, turpentine resin is a suspension of substances comprising levopyamic acid, neoabiotic acid, palussic acid, abietic acid, dehydroabietic acid, dry-dehydroabietic acid, tetrahydroabietic acid, dihydroabietic acid, pimaric acid, and isopimaric acid. Turpentine resin derived from natural sources also includes resins, i.e. suspensions of turpentine resin, particularly modified by polymerization, isomerization, disproportionation, hydrogenation, and Diels-Alder reactions with acrylic acid, anhydrides, and acrylic acid esters. The products obtained by these processes are known as modified turpentine resins. The natural turpentine resin can also be chemically altered by any process known in the art, such as for example the reaction of the carboxyl group of the turpentine resin with metal oxides, metal hydroxides or salts to form soaps or salts of turpentine resin (called resinates ). Said chemically altered turpentine resin is referred to as turpentine resin derivatives.

Said turpentine resin can be modified or chemically altered by introduction of an organic group, an anionic group or a cationic group. The organic group may be a substituted or unsubstituted aliphatic or aromatic hydrocarbon having 1 to 40 carbon atoms. The anionic group can be any anionic group known to those skilled in the art, such as a carboxylate or a sulphonate.

Additional details of these turpentine resin-based materials can be obtained from D.F. Zinkel and J. Russell, in Naval Stores, Production-Chemistry-Utilization, 1989, New York, Section II, Chapter 9) and J.B. Class ("Resins, Natural", Chapter 1: "Rosin and Modified Rosins", Kirk-Othmer Encyclopedia of Chemical Technology, online registration date December 4, 2000). The use of LDHs of the invention comprising one or more organic anions is also contemplated. In one embodiment, the intercalation anions are a mixture of fatty acid and turpentine resin.

As a general rule, at least 10% of the total amount of intercalation ions in the types of LDH according to the invention is an organic anion, preferably at least 30%, more preferably at least 60%, and most preferably at least 90 % of the total amount of intercalation ions is an organic anion. In a preferred embodiment, at least 10% of the total amount of intercalation anions is an anion derived from fatty acid or an anion based on turpentine resin or a suspension of both anions, preferably at least 30%, more preferably at least 60 %, and most preferably at least 90% of the total amount of intercalation ions is an anion derived from fatty acid or an anion based on turpentine resin or a mixture of both anions.

The present invention is further illustrated in the following examples.

EXAMPLES

Example 1

A commercially available fatty acid was used, as received. Kortacid® PH05, a mixture of palmitic and stearic acid, was supplied by Oleochemicals GmbH, a company of Akzo Nobel Chemicals.

50 grams of magnesium oxide (Zolitho® 40 from Martin Marietta Magnesia Specialties LLC) and 39 grams of aluminum trihydroxide (Alumill F-515) were mixed in 648 grams of demineralized water and ground to an average particle size (d50) of 2.5 µm. The paste was fed to an oil-heated autoclave, equipped with a high speed stirrer and heated to 80 ° C. 102 grams of Kortacid® PH05 were then added to the autoclave over a period of 15 minutes. Before the addition, the fatty acid mixture was heated to 80 ° C. After the addition of the acid, the autoclave was closed and heated to 170 ° C and maintained under these conditions for one hour. The autoclave was then cooled to approximately 40 ° C and the resulting paste was separated. The paste was then centrifuged at 2000 rpm for approximately 10 minutes. The liquid was decanted and the solids dried under vacuum in an oven overnight at 80 ° C.

The resulting hydrotalcite-like clay that comprised the fatty acid mixture was made with X-ray diffraction to determine inter-gallery spacing or spacing d. The XRD pattern of the hydrotalcite-like clay as prepared above exhibits minor reflections related to hydrotalcite of a type other than (hk0), indicating the intercalation of the anionic clay. The interleaved material exhibits a characteristic value d (001) of 29 A.

Example 2

A stabilized turpentine resin was produced in the laboratory of the inventors by melting Chinese turpentine resin and heating it at 235 ° C. During melting, 3.5% of Vultac®-2 (Arkema Inc.) by weight based on turpentine resin was added. The molten turpentine resin was stirred at 235 ° C for 15 hours, after which the resin was cooled and was ready for use.

50 grams of magnesium oxide (Zolitho® 40, from Martin Marietta Magnesia Specialties LLC) and 39 grams of aluminum trihydroxide (Alumill F505) were mixed in 648 grams of demineralized water and ground to an average particle size (d50) of 2.5 µm. The paste was fed to an oil-heated autoclave, equipped with a high speed stirrer and, after closing it, heated to 120 ° C. 115 grams of stabilized turpentine resin were then added to the autoclave as mentioned above over a period of 30 minutes. Before the addition, the turpentine resin mixture was also heated to 120 ° C. After the acid addition, the autoclave was heated to 170 ° C and maintained under these conditions for one hour. The autoclave was then cooled to approximately 40 ° C and the resulting paste was separated. The paste was then centrifuged at 2000 rpm for approximately 10 minutes. The liquid was decanted and the solids dried under vacuum in an oven overnight at 80 ° C.

The resulting hydrotalcite-like clay comprising the mixture of fatty acids was analyzed by X-ray diffraction to determine inter-gallery spacing or spacing d. The XRD pattern of the hydrotalcite-like clay prepared above shows minor reflections other than (hk0) related to the hydrotalcite, indicating the intercalation of the anionic clay. The interleaved material exhibits a characteristic value d (001) of 23 A.

Example 3

252 grams of magnesium oxide (Zolitho® 40, from Martin Marietta Magnesia Specialties LLC) and 240 grams of aluminum trihydroxide (Alumill F505) were mixed in 3,513 grams of demineralized water and ground to an average particle size (d50 ) of 2.4 µm. Part of this paste (704 grams) was fed to a glass reactor equipped with stirrer, nitrogen stream, and reflux refrigerant. The paste was heated to 90 ° C. Then 147 grams of molten Kortacid PH05 (T = 90 ° C) was added to the glass reactor over a period of 90 minutes. The reaction mixture was maintained at 90 ° C for a further 19 hours and then cooled below 50 ° C. The resulting paste was then centrifuged at 2000 rpm for approximately 10 minutes. The liquid was decanted and the solids dried under vacuum in an oven heated to 80 ° C.

The resulting hydrotalcite-like clay comprising the mixture of fatty acids was analyzed by X-ray diffraction to determine inter-gallery spacing or spacing d. The XRD pattern of the hydrotalcite-like clay prepared above shows minor reflections related to hydrotalcite other than (hk0), which indicate the intercalation of the anionic clay. The interleaved material exhibits a characteristic value d (001) of 28 A.

Claims (7)

1. Process for preparing an organically modified double stratified hydroxide having a distance between the individual layers of the stratified double hydroxide greater than 1.5 nm determined according to the method of the description, and comprising an organic anion as equilibrium anion of loads, the process comprising the steps of:

(to)

preparing a precursor suspension comprising a source of divalent metal ions and a source of trivalent metal ions;

(b)

subject the precursor suspension to solvothermic treatment to obtain the double stratified hydroxide,

wherein an organic anion is added before or during the formation of the double stratified hydroxide of step (b), or after the formation of the double stratified hydroxide, in order to obtain the organically modified double stratified hydroxide, and where the organic anion has 8 or more carbon atoms, with the proviso that the only organic anion present as a charge balancing anion is not terephthalate, where the source of divalent metal ions and / or the source of trivalent metal ions is ground before from step (b), and where water is used as a suspension medium, with the proviso that deoxycholic acid is not the only organic anion. 2. Process for preparing an organically modified double stratified hydroxide having a distance between the individual layers of the stratified double hydroxide greater than 1.5 nm determined according to the method of the description, and comprising an organic anion as equilibrium anion of loads, the process comprising the steps of:

(to)

preparing a precursor suspension comprising a source of divalent metal ions and a source of trivalent metal ions;

(b)

heat the precursor suspension to obtain the double stratified hydroxide,

wherein an organic anion is added before or during the formation of the double stratified hydroxide of step (b), or after the formation of the double stratified hydroxide, in order to obtain the organically modified double stratified hydroxide, and where the organic anion has 8 or more carbon atoms, with the proviso that the only organic anion present as a charge balancing anion is not terephthalate, where the source of divalent metal ions and / or the source of trivalent metal ions is ground before of step (b), and where water is used as a suspension medium, with the proviso that in step a) the source of trivalent metal ions is not reacted with the organic anion at a temperature between 60 and 85 ° C for 4 to 8 hours before the addition of the source of divalent metal ions and step b) is subsequently carried out at a temperature of 90 to 95 ° C for 4 to 8 hours. 3. A process according to claim 1 or 2, wherein the organic anion is added to the precursor aqueous suspension before passing step (b). 4. A process according to claim 1 or 2, wherein the organic anion is added after the formation of the double stratified hydroxide, wherein the double stratified hydroxide mainly has hydroxyl as a charge balancing anion. 5. A process according to any one of the preceding claims, wherein the divalent metal ion is Mg2 + and the trivalent metal ion is Al3 +. 6. A process according to any one of the preceding claims wherein the d50 value of the source of divalent metal ions and / or the source of trivalent metal ions is less than 10 µm. 7. A process according to any one of the preceding claims, wherein the organic anion has 10 to 40 carbon atoms.