TW200829511A - Process for preparing layered double hydroxide comprising carbonate - Google Patents

Abstract

The invention relates to a process for preparing a layered double hydroxide comprising carbonate as charge-balancing anion comprising the steps of: (a) reparing a slurry or solution comprising a trivalent metal ion source, a divalent metal ion source, and a suspending medium, the divalent metal ion source being a source, free of carbonate and/or a source containing carbonate; (b) olvothermally treating the slurry or solution, and optionally adding a carbonate source to the slurry during or after the solvothermal treatment, to form the layered double hydroxide comprising carbonate; and if the slurry or solution does not contain a divalent metal ion source containing carbonate, a carbonate source is added to the slurry or solution during or after the solvothermal treatment.

Description

200829511 IX. DESCRIPTION OF THE INVENTION: TECHNICAL FIELD The present invention relates to a method of preparing a layered double hydroxide comprising a carbonate ion as a charge balancing anion. [Prior Art] DE 1〇2 17 364 describes the production of hydrotalcite by thoroughly grinding agglomerates containing oxides, hydroxides or carbonates of a valence metal and a divalent metal under normal pressure and low s1 〇 (rc). 'The carbonate may be MgC〇3 or Mg(HC03)2 〇 US 4,539,195 discloses a process for the conversion of aluminum hydroxide with basic magnesium carbonate and at least one compound selected from magnesium hydroxide and magnesium oxide. A method of basic magnesium aluminum hydrogen carbonate hydride of AhMgJOHhdCC^VxHzO. The conversion takes place at a temperature between 50 ° C and 100 ° C. WO 96/05140 describes a method for producing synthetic hydrotalcite, wherein Mg5(C〇3)4(OH)2.4H2〇) and alumina source (rehydratable alumina or pseydoboehmite) are converted at various temperatures ranging from 50 ° C to 90 ° C It is an object of the present invention to provide an improved method for preparing a layered double hydroxide comprising a carbonate ion as a charge-balancing anion. The object can be prepared by using a charge-balanced anion. Achieved by a method of layered double hydroxide of carbonate ions The method comprises the following steps: a) preparing a slurry or solution comprising a trivalent metal ion source, a divalent metal ion source and a suspension medium, the divalent metal ion source is free of carbonate ion source and/or Or a source containing carbonate ions; b) thermally treating the slurry or solution, and optionally adding a source of carbonate ions to the slurry during or after the solvothermal treatment to form carbonate-containing ions A layered double hydroxide; and if the slurry or solution is free of a source of divalent metal ions containing carbonate ions, a source of carbonate ions is added to the slurry or solution during or after the solvothermal treatment.

An advantage of the method of the present invention is that it can be completed in a shorter period of time than conventional methods performed at atmospheric pressure τ, which makes the method economically more attractive. In addition, there is no need for hydrothermal post-treatment or (4) reduced time required for post-treatment, thus further shortening the production process. The amount of sub-^ is to form a circle having a desired amount of carbonate ions between the layers. However, if the method of the present invention of carbonate ions can be prepared by preparing a slurry or solution containing a source of a trivalent metal ion, a source containing a carbonate ion, and a source of a divalent metal ion not containing a carbonate ion. And proceed. If the amount of carbon added during or after the step b) before, during or after the step b) of the carbonate in the slurry or solution is insufficient, a carbonate ion source is usually added in the process. Preferably, the source of acid ions. Alternatively, in the slurry or solution of the right step a), the source of the carbonate ion containing the carbonate ion is not required to add the carbonate ion source before, during or after the step lion to make the #白& Package 3 serves as the LDH of the carbonate ion of the charge balancing anion. In the preferred embodiment, the carbonate ion source is added during or after step 125012.doc 200829511. The source of carbonate ions can be any suitable source of carbonate ions known in the art. Examples of such carbonate ion sources are carbon dioxide (c〇2), alkali metal carbonates such as sodium or potassium carbonate, and metal hydrogencarbonates such as sodium hydrogencarbonate or potassium hydrogencarbonate. It is also contemplated to use one or more sources of carbonate ions. These sources can be added simultaneously or at different stages of the method. Carbon dioxide is preferred among such carbonate ion sources because it does not add to the slurry or solution a salt that will terminate in the waste stream and need to be removed. The invention further relates to a layered double hydroxide comprising carbonate ions as charge balancing anions having an average L/D value above 1 〇〇. These LDHs can be prepared by the method of the invention as described above. The layered double hydroxide of the present invention differs from the LDH containing carbamate ions known in the art in that the average L/D of the ldh of the present invention is significantly higher than the L/D value observed by the known LDH. The latter is well below 100. As indicated, the LDH of the present invention has a different form than the conventional 〇1!. The average ratio of the length to the diameter (L/D ratio) of the individual thin layers in the LDH exceeds 100, preferably the L/D ratio is at least 15 Å, more preferably the l/d ratio is at least 200, and even More preferably, the L/D ratio is at least 25 〇. The L/D ratio can be measured using an electron microscope such as a scanning electron microscope (SEM) and/or TEM. The length is the largest dimension of the layers in a direction perpendicular to the stacking direction and the diameter refers to the thickness of the clay particles in the stacking direction. I have noted that the average length and average diameter can be determined, for example, by taking the average length and average diameter of two clay particles. As long as the average is statistically reasonable, the number of clay particles may be larger or smaller. 125021.doc 200829511 Alternatively or additionally, the LDH of the present invention typically has individual thin layers having an average length of at least 400 nm; preferably the average length is at least 5 〇〇 nm, and optimally the average length is at least 6 〇 〇nm. This average length is defined and determined using the method described above for the L/D value. [Embodiment] In the context of the present application, the term "charge-balancing anion" refers to an anion that compensates for the loss of static charge of a crystalline clay sheet of LDH. Because the clay pass 4 has a layered configuration, the charge balance anions can be located on the interlayer, edge or outer surface of the stacked clay layers. These anions located in the layers of the stacked adhesive layers are referred to as intercalated ions. The LDH containing a charge-balanced organic anion has a layered structure corresponding to the following formula: [M^+(0H)2m+2Jx-.bH20 (1) wherein lanthanum such as Zn2+, Mn2+, Ni2+, Co2+, Fe2+, Cu2+,

Divalent metal ions of Sn2+, Ba2+, Ca2+, and Mg2+, such as M3+

The trivalent metal ions 'm and n' of Al3+, Cr3+, Fe3+, Co3+, Μη3+, Ni3+, Ce3+, and Ga3+ have values such that m/n = 1 to 1 〇, and b has a value in the range of q to i 。 . It is also contemplated to use two or more different metal ions in the layered dihydrogen oxide prepared by the process of the present invention. Among the above metal ions, a combination of Mg2+ and/or Zn2+ is preferred as the divalent metal ion and Al3+ is used as the trivalent metal ion. A mixture of a lanthanide carbonate ion (c〇32_) or a carbonate ion with one or more inorganic anions or organic anions known in the art. In addition to carbonate ions, examples of suitable inorganic anions include 125021.doc 200829511 including hydroxide ions, hydrogencarbonate ions, nitrate ions, chloride ions, bromide ions, sulfonate ions, sulfate ions, hydrogen sulfate ions, Vanadate ion, tungstate ion, borate ion and phosphate ion. For the purposes of this specification, carbonate anions and bicarbonate anions are defined as being inorganic. Examples of suitable organic anions are found in US 5,728,366 and US 2005/020749. The LDH of the present invention comprises an anionic LDH of hydrotalcite and hydrotalcite-like. Examples of such LDHs are magnesite, bauxite, magnesite, sj6Srenite, chromite, hydrochromite, bauxite, water. Carbonite and carbon hydrated manganite. In one embodiment of the invention, the layered double hydroxide has a layered structure corresponding to the following formula: teAI^(0H)2m+2n]x-.bH20 (Π) wherein m and η have values such that Melon / 11 = 1 to 1 Torr, preferably 1 to 6, more preferably 2 to 4, and most preferably a value close to 3; having a value in the range of 〇 to 1 ,, 10 usually 2 to 6 Value, and often a value of about 4. X is a charge balancing ion as defined above. m/η should preferably have a value of 2 to 4, more preferably a value close to 3. In another embodiment of the invention, the layered double hydroxide has a layered structure corresponding to the following formula: Mg-Z/7- A!-(〇H)2m+2n+2Jx-. bH2〇(HI) wherein m and n have values such that (m+n)/p=1s1〇, preferably 1 to 6 More preferably 2 to 4, and most preferably a value close to 3; b has a value of 125021.doc -10- 200829511 in the range of 〇 to 1〇, usually a value of 2 to 6, and often about 4 value. The lanthanide is a charge balancing ion as defined above. Preferably, (m + n) / p should have a value of 2 to 4, more preferably a value close to 3. LDH can have any crystal form known in the art, such as by

Cavani et al. (CWa/j; ❿ TWw, 11 (1991), pp. 173-3 01) or by Bookin et al. (:/Mr. Mhera/s, (1993), Volume 41 (5), 558 - page 564) The crystal form described, such as 3Hi, 3h2, 3Ri or % stacked. In an embodiment, the LDH has a 3R! stack. • In the context of this application, the terms solvothermal treatment "and solvothermal method" mean the pressure at a pressure above atmospheric pressure and the boiling point of a precursor suspension or solution at substantially higher than atmospheric pressure. The precursor suspension/slurry or solution is treated at a temperature of from 200 bar to 200 bar, preferably from 2 bar to 1 bar, and most preferably from 3 bar to 10 bar. Typically, this temperature 1 〇〇〇c or higher, preferably 10 (TC to 30 (TC, more preferably 11 (rCs25〇t:, and good g12 (rc to 200 C.) for use in the suspension of the method of the present invention The medium may be any suitable suspending medium known in the art. The suspending medium includes water, an organic solvent or a mixture thereof. Suitable examples of the organic solvent include alcohols such as methanol, ethanol, 1-propanol and isopropanol; An alkoxylated alcohol such as propylene glycol monomethyl ether and propylene glycol ethyl ether; and an alkane such as pentane, hexane and heptane; (iv) an aromatic hydrocarbon such as benzene, toluene and dimethyl stearate. The suspension medium comprises water v alcohol and/or alkoxylated alcohol. It will also contain water and organic solvents or only water. The solvothermal treatment in the neat medium is called "hydrothermal treatment," the carbonate-containing divalent metal ion source, the trivalent metal ion source and the carbonate-free ion used in the method of the present invention. Divalent metal ion source 125021.doc -11- 200829511 may be any source known to those skilled in the art. Such sources include soluble salts of divalent metal ions and/or trivalent metal ions, and insoluble or partially insoluble. a divalent metal ion source and a trivalent metal ion source or a mixture thereof. The soluble salts of the metal ion source include nitrates, chlorides, perchlorates, and aluminates. These are insoluble or partially insoluble. The divalent metal ion source and the trivalent metal ion source generally comprise oxides or hydroxides or carbonates of the divalent metal ions or trivalent metal ions. Preferably, the sources are insoluble or partially soluble. Preferably, the divalent metal ion source and the trivalent 10* ion source oxide and/or hydroxide. In the context of the present application, "soluble salt" means at room temperature Completely dissolved and form a clear solution A valence metal ion source and a trivalent metal ion source. In the context of the present application, the term "insoluble or partially insoluble" means a source that does not completely dissolve at room temperature and forms a suspension. Examples of divalent metal ions It is Zn2+, Mn2+, Ni2+, c〇2+, Fe2+, Cu2+, Sn2+, 仏2+, Ca2+ and 峋2+. The real ternary metal ions are exemplified by Al3+, Cr3+, Fe3+, Co3+, Mii3+, Ni3+, Ce3. + and Ga3+. It is also contemplated to use three or more different metal ions in the layered double hydroxide prepared by the method of the present invention. Among the above metal ions, a combination of Mg2+ and/or Ζη2*1' is preferred. And αι3+. ', . The source of magnesium ions containing carbonate ions is usually selected from the group consisting of magnesium hydrogencarbonate, hydromagnesite (Mg5(C〇3)4(OH)2), magnesium carbonate, magnesium hydrogencarbonate and dolomite. . Combinations of two or more sources of magnesium ions containing carbonate ions are also contemplated. Examples of suitable magnesium ion sources that are insoluble or partially insoluble include oxidation 125021.doc •12· 200829511 lock, magnesium hydroxide, magnesium hydrogencarbonate, hydrotal magnesium, ore (Mg5(C03)4(〇H)2 ), magnesium carbonate, magnesium sulphate, dolomite and sepiolite. The magnesium ion source free of carbonate ions may be magnesium oxide or magnesium hydroxide. Combinations of two or more sources of magnesium ions are also contemplated. The ion source containing carbonate ions is usually selected from the group consisting of zinc oxycarbonate, carbonated acid and zinc hydrogencarbonate. Combinations of two or more sources of zinc ions containing carbonate ions are also contemplated.

Examples of suitable sources of zinc ions that are insoluble or partially insoluble include oxidizing, zinc hydroxide, zinc oxycarbonate, zinc carbonate, and zinc hydrogencarbonate. The zinc ion source containing no carbonate ions may be zinc oxide or zinc hydroxide. Combinations of two or more sources of reciprocal ions are also contemplated. It is also contemplated to use a combination of at least one source of magnesium ions and at least one source of zinc ions. The source of insoluble or partially insoluble aluminum ions is typically aluminum hydroxide or aluminum oxide. Examples of such sources of aluminum ions are those known to the skilled artisan such as Sanshui Mingshi and Sanshui Mingling, such as water-mineral, water-stone or goethite, and transitional type. Alumina. Since the relatively small amount of salt (if present) remains in the waste stream produced by this method, the above-described insoluble or partially soluble divalent metal ion source and trivalent metal ion source are provided in the method of the present invention. A more environmentally friendly approach. In addition, the source of the divalent metal ion and the source of the trivalent metal ion are: the source of the magnesium ion source, the source of the ion, and the source of the source of the scorpion, and the price of the corresponding salt is usually changed in the layered double hydroxide. low. In addition, because the method of the present invention requires " to handle the waste stream, it is generally 爰 and the knife is early. Moreover, such methods J2502I.doc 200829511 can be performed in a shorter period of time, which in turn can result in higher productivity of layered double hydroxides compared to conventional methods. In a preferred embodiment of the invention, the insoluble or partially soluble divalent metal ion source and/or the trivalent metal ion source, and in particular the magnesium ion source, the zinc ion source and/or the aluminum ion source are Grinding is carried out before step (b). These metal ion sources can be ground in the presence of a suspending medium or without a suspending medium. In the method of the present invention, the divalent metal ion source and/or the divalent metal ion source generally have a d50 value of less than 2 〇 μηι and a d90 value of less than 50 μπι. Preferably, the Mo value is less than 15 μπ! and the d90 value is less than 40 μπι, more preferably the d5〇 value is less than 1〇μπι and the d90 value is less than 30 μπι ' even better preferably the d5〇 value The system is less than 8 and the d9〇 value is less than 20 μηι′ and the d5〇 value is less than 6 μπι and the d90 value is less than 1〇μηι. Can be used, for example, according to! ^^ 1332 雷 Laser diffraction is known in the art to determine the particle size distribution. This grinding step allows the formation of the layered double hydroxide to proceed more quickly. If the divalent metal ion source and the trivalent metal ion source are a magnesium ion source and an aluminum ion source, this step can further reduce the amount of impurities such as gibbsite or brucite. Typically, at least 10% of the total amount of charge balancing anion is carbonate ion, preferably at least 30%, more preferably at least 60%, and optimally, at least 90% of the total charge balance anion is carbonate ion. It is also expected that 100% of the total charge balance anion is carbonate ion. In one embodiment of the invention, a mixture of a source of divalent metal ions containing carbonate ions and a source of divalent metal ions additionally containing no carbonate ions is used. The weight ratio of one metal ion source containing urate ions to the source of 125021.doc -14 - 200829511 divalent metal ion source containing no carbonate ions is usually from 1 00:1 to 1:100, preferably 50:1. To 1:50, and the best is from ΐ〇··ι to m〇. In one embodiment of the invention, the LDH is treated with a coating agent to render the LDH more hydrophobic. This coating agent can be any coating agent known in the art. Examples of such coating agents include monocarboxylic acids, dicarboxylic acids or polycarboxylic acids, sulfonic acids, phosphonic acids and sulfuric acid, mercaptans, benzene mercaptans (benz〇thi〇1), phenols and salts thereof, and only examples. It is a fatty acid having 8 to 22 carbon atoms or a salt thereof. In the context of this application, the term "fatty acid" refers to the acid and the salt of the acid. This fatty acid can be a saturated fatty acid or an 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, palmitic acid, oleic acid, linoleic acid, linoleic acid and Its mixture. Preferred fatty acids are stearic acid and its salts. A coating agent is used to increase the hydrophobicity of LDH. and to improve its compatibility with a polymer matrix such as polyvinyl chloride (PVC). This fatty acid treatment can be carried out in any manner known in the art. The fatty acid can be added before, during or after step b) of the process of the invention. After the formation of ldh, the fatty acid can be added to the slurry in a molten or solid form. The fatty acid may also be added to the slurry or solution before or during the thermal treatment of the solvent of step b). Since the resulting product of the latter route is more hydrophobic and its compatibility with a polymer matrix such as pvc is improved, it is superior to the previous route. In addition, the treated LDH can form less coalescence and can be more finely and uniformly distributed throughout the polymer matrix. It is believed (and is not intended to be bound by any theory) that the treated ll 11 is more effectively and more widely coated than the treated LDH obtained via the post-treatment path. Alternatively, the fatty acid may be added to the slurry or solution as a magnesium or zinc salt in step a) or step b) of the process of the invention 125021.doc -15-200829511. The advantage of this is that the magnesium salt of the fatty acid salt Ions and/or zinc ions can be used to form the LDH such that there is no residual salt in the waste stream. Suitable examples of such fatty acid salts are magnesium stearate and zinc stearate.

The amount of the coating agent used in the method of the present invention is usually 重量·〇1 by weight (wt%) to 10 wt%, preferably 0, based on the weight of the divalent metal ion source and the trivalent metal ion source. 1 wt% to 8 wt%, and most preferably 〇2 wt% to 5 wt% 〇 Therefore, the present invention also relates to a process obtained by adding a fatty acid before or during step b) of the process of the present invention. The layered double hydroxide is treated. The LDH prepared according to the method of the present invention can be used in applications where such carbonic acid ion-containing LDH is conventionally used. An example is the use of the LDH described above in PVC. The invention is further illustrated in the following examples. EXAMPLES Commercially available fatty acids are used as they are. Blend of palmitic acid with stearic acid by oleochemicals GmbH, Akz〇 〇bel Chemicals

Kortacid® PH05 〇y Example 1 Grinding contains an ancient in a bead mill... There are 2" g, 38.9 g Me0, 48.7 g ΑΊΉ and 1,386 g de-hoc 2, 8 g 〇 at 2.5 μπι and 3. 〇 _ 3 Has an average particle size (using Malvern 125021.doc -16- 200829511

Mastersizer S measurement) solid slurry. The ground product was transferred to a 2 1 high pressure crucible. The slurry was stirred and heated to 170 ° C and held at this temperature for 60 minutes. Subsequently, the slurry was cooled to room temperature. Dry white solid. XRD analysis and infrared analysis revealed the formation of hydrotalcite (having carbonate ions as charge balance anions). The average L/D value was determined using a scanning electron microscope (SEM); the average L/D value was about 260. The average length of individual thin layers is much higher than 600 nm. For comparison, the average L/D value of a commercial LDH (i.e., Alkamizer 1, available from Kyowa) containing carbonate ions as charge-balanced anions was determined. The average L/D value was determined to be about 55. The average length of individual thin layers is about 300 nm. Example 2 Grinding contains 37.7 g of hydromagnesite (4MgC03.Mg(0H)2.5H20), 35.5 g of MgO, 48.4 g of ATH and 1,378 g in a bead mill. The aqueous slurry of deionized water was used to obtain a slurry containing a solid having an average particle diameter between 2.5 μm and 3.0 μm (measured using a Malvern Mastersizer S). The ground product was transferred to a 21 high pressure mark. The slurry was stirred and heated to 170 ° C and maintained at this temperature for 60 minutes. Thereafter, the slurry was cooled to 85 ° C and molten Kortacid PH05 (1.4 g per 1, g g slurry) was added, stirred for further 60 minutes, cooled to room temperature, and the solid was dried. XRD analysis and infrared analysis revealed the formation of hydrotalcite (having carbonate ions as charge-balanced anions). The hydrotalcite product contained stearic acid and palmitic acid and exhibited enhanced hydrophobic properties compared to the uncoated hydrotalcite of Example 1. This enhanced hydrophobic property was confirmed by the formation of two layers of 125021.doc -17-200829511: the first upper layer was a slurry of hydrotalcite product and the second bottom layer was a clear layer of water discharged from the slurry. Example 3 Grinding in a bead mill containing 37·7 g of water magnesite (4MgC〇rMg(〇H)2.5H2〇), 35·5 g Mg〇, 48 4 g ATJJ and 1,378 g of deionized water The aqueous slurry is obtained to have an average particle size between 2·5 and 3·0 μπι (measured using Ma vern Masteisizer s)

a slurry of solids. The ground product was transferred to a 2-inch autoclave. The slurry was stirred and heated to 170 ° C and held at this temperature for 6 Torr. Subsequently, the slurry was cooled to 80 ° C and sodium stearate ((10) g g g g) was added, stirred for further 60 minutes, cooled to room temperature, and the solid was dried. Xrd analysis and infrared analysis revealed the formation of hydrotalcite (having carbonate ions as charge-balanced anions). The hydrotalcite product contained stearates and exhibited enhanced hydrophobic properties compared to the uncoated hydrotalcites of the examples. This enhanced hydrophobic property consists of forming a two layer of solid, first-upper layer of hydrotalcite product and a second bottom layer of clear water from the slurry. Example 4 A water-containing transition containing 37.7 g of hydromagnesite (4MgC〇3.Mg(OH)2.5H2〇), 35 5 g of Mg〇, 48 4 ^fine and deionized water was ground in a bead mill. A solid aggregate having a mean particle size between 2.5 μm and a Malvern M (6) was obtained. Transfer the ground product to 2! High pressure dad, and KW brain (each 1, 蜱 feed 1.4 d added to the water containing material 125021.doc -18. 200829511 The slurry is stirred and heated to 17〇c, It was kept at this temperature for 18 minutes. Subsequently, the slurry was cooled to warmness. The white solid was dried. XRD analysis and infrared analysis revealed the formation of hydrotalcite (having carbonate ions as charge-balanced anions). Contains stearic acid and palmitic acid and exhibits enhanced hydrophobic properties compared to uncoated hydrotalcites in the examples. Since the clear aqueous layer of this example is twice as large as the clear layer obtained in Example 2, the water The talc product further exhibited significantly enhanced hydrophobicity compared to the coated hydrotalcite of Example 2. Example 5 An aqueous slurry containing 41.8 g of MgO, 39.6 g of ATH, and 1,419 g of deionized water was ground in a bead mill. The slurry was obtained to obtain a slurry containing a solid having an average particle size between 2·5 μm and 3 Torr (measured using a Malvern Mastersizer S.) The ground product was transferred to a 21 autoclave and heated to i5 〇〇. c. After 90 minutes, C〇2 gas was injected into the autoclave to raise the high pressure dad to 5 bar' to maintain the pressure for 4 hours. After 4 hours, the injection of C〇2 was stopped. The resulting slurry was cooled to room temperature and dried white. Solid.xrd analysis and infrared analysis revealed the formation of hydrotalcite (having carbonate ions as charge-balanced anions). Example 6 Grinding in a bead mill containing 34.3 g of basic zinc carbonate (Zn5(C03)2(0H)6) An aqueous slurry of 30.2 g MgO, 48.8 g ATH and 1,3 78 g deionized water to obtain a slurry containing solids having an average particle size between 2.5 μχη and 3.0 μηη (measured using a Malvern Mastersizer S) 125021.doc -19- 200829511 The ground product was transferred to a 21 autoclave. The slurry was stirred and heated to 170 ° C and held at this temperature for 60 minutes. Subsequently, the slurry was cooled to 85. Add molten Kortacid PH05 (1·4 g per 1,000 g of slurry) and stir for another 60 minutes. Dry solids. XRD analysis and infrared analysis revealed the formation of hydrotalcite (having carbonate ions as charge-balanced anions) The hydrotalcite product contains stearic acid And palmitic acid and exhibit certain hydrophobic properties. The average L/D value was determined using a scanning electron microscope (SEM) with an average L/D value of about 260. The average length of individual thin layers is much higher than 600 nm. For comparison, the average L/D value of commercial zinc-containing LDH (meaning Alkamizer 4, available from Kyowa) containing carbonate ions as charge-balanced anions was determined. The average L/D value was determined to be about 55. The average length of individual thin layers is about 300 nm. Example 7 Grinding in a bead mill contains 34.3 g of basic zinc carbonate (Zn5(C03)2(0H)6), 30·2 g MgO, 48·8 g ATH And an aqueous slurry of 1,378 g of deionized water to obtain a slurry containing a solid having an average particle size between 2 and 5 μηη and 3.0 μηη (measured using a Malvern Mastersizer S). The ground product was transferred to a 21 high pressure crucible and Kortacid PH05 (1.4 g per 1, g g slurry) was added to the aqueous slurry. The slurry was stirred and heated to 170 ° C and held at this temperature for 60 minutes. Subsequently, the slurry was cooled to room temperature. Dry solid. XRD analysis and infrared analysis revealed the formation of hydrotalcite (having carbonate ions as charge-balanced anions). The hydrotalcite product contained stearic acid and palmitic acid and was shown to have the enhanced hydrophobic character, acid, as compared to Example 6, which gave 125021.doc -20-200829511 where hydrotalcite was added after the reaction.

125021.doc -21 -

Claims (1)

200829511 X. Patent Application Range: A method for preparing 层3 as a layered double hydroxide of a carbonate ion of a charge-balanced anion, comprising the steps of: a) preparing a source comprising a divalent metal ion, a source of a divalent metal ion, and Suspended water or > trough, the divalent metal ion source is free of carbonate ion source and / or carbonate ion source; b) solvothermal treatment of the slurry or solution 'and Wherein a carbonate ion source is added to the polymer during or after the solvothermal treatment to form the carbonated ion-containing layered double hydroxide; and if the slurry or solution does not contain carbonate ions A source of divalent metal ions is added to the slurry or solution during or after the 'treat thermal treatment. ^#Method of claim 1 wherein: the valence metal ion is a town ion and/or a zinc ion and the trivalent metal ion is an aluminum ion. The method of any one of the items 1 and 2, wherein the source of the divalent metal ion is a group of k-free hydroxyhydrogen, hydromagnesite, strontium carbonate, chlorinated carbon and dolomite. The method of any one of items 1 and 2, wherein the source of the additional divalent metal ion is selected from the group consisting of MgG, water town; 5, cesium carbonate and mixtures thereof. A method wherein the aggregate is prepared in a step hook. 6. As requested! The method of any of 2, wherein the source of carbonate ions is an emulsified carbon. 125021.doc 200829511 7. A solution according to any one of claims 1 and 2 to form a treated #^ [addition to the pulp or & method of claim 7, a complex oxide. 9. The layered double hydroxide acid is added prior to step b). The acid ion 'the charge balance equilibrium anion carbon' has an average L/D value back to 100. ": 2 / 2 double hydroxide ' where the layered double hydroxide is determined by Obtained by the method of any of 8. Sub-two:: layered double hydroxide, which is included as a charge balance 12: a sub- can be obtained by the method of claim 8. A gas, which contains as an optional double hydroxide. Layered 125021.doc 200829511 VII. Designation of the representative representative: (1) The representative representative of the case is: (none) (2) The symbol of the symbol of the representative figure is simple: 8. If there is a chemical formula in this case, please reveal the best indication of the characteristics of the invention. Chemical formula: [KKm) 2m+2n ]Xn/;*bH20 125021.doc