Title of Invention

A PROCESS FOR THE MANUFACTURES OF ALUMINUM SILICATES

Abstract

A process for the manufacture of alumino-silicates which are dispersible in aqueous and/or aqueous-acidic media, characterized in that, one or more hydrolysable aluminum compound(s) as herein described (are) hydrolyzed jointly or separately from each other, preferably jointly, and prior to, during, or after hydrolysis, said compound(s) (are) contacted with one or more silicic acid compound(s) as herein described, and after hydrolysis or also already during hydrolysis, the reaction products are jointly subjected to hydrothermal ageing in aqueous medium and in the presence of a monovalent organic C1- to C6- acid or a monovalent inorganic acid as herein described at temperatures of 40 to 220°C for a period of 0.5 hour to 24 hours; and optionally, the aforesaid products are calcined at temperatures between 550°C and 1500°C for a period of 0.5 hours to 24 hours. Whereby the aluminum compound/silicon compound ratio used is from 99.5 wt. %:0.5 wt. % to 70wt%:30wt%, each referring to the ratio of A12O3 : SiO2-

Full Text

The present invention relates to a process for the manufacture of alumino-silicates . The present invention relates to a process for the manufacture of high-purity alumino-silicates which are dispersible in aqueous or aqueous-acidic media by hydrolysis of aluminium compounds and silicic acid compounds and hy-drothermal treatment. There exists a large number and wide variety of natural alumino-silicates, including many compounds having defined crystalline structures, such as muscovite, nepheline, and chabasite. When exchanging part of the silicon atoms in the reticulation of silicates for aluminium atoms, while maintaining the reticulation, zeolithes are obtained. Besides natural alumino-silicates, there are many synthetic products of this kind. Such products may be those defined by crystal chemistry or may be physical mixtures of aluminium hydroxide and silicic acids with different quantities of water. Besides physical mixtures, alumino-silicate defined by crystal chemistry may be present as well. A customary process for preparing such alumino-silicates is the conversion of clays, such as kaolin, using silicic acid and sodium hydroxide. Another synthesis route is the cogelation of aluminium hydroxide sols with silicic acid sols followed by precipitation [cf. GB 2166971-C]. Precipitation of an aluminium salt in a silicic acid sol is known as well [cf. CA 848966-A]. The aforesaid processes have the disadvantage that the desired sols or emulsions only exist at the instant they are prepared, while the powder obtained by subsequent drying can only incompletely be dispersed or requires solvent mixtures to achieve dispersion. Another disadvantage is that the sols or emulsions prepared in this way contain large quantities of alkali metals or alkaline earth metals used for stabilising the silicic acid. Subsequent purification, e. g. by ion exchange, is incomplete and results in typical concentrations of alkali metals or alkaline earth metals of 0.1 % (equal to 1,000 ppm) after purification (cf. US 3,933,6211. Heterogeneous catalysis requires high-purity catalyst supports containing less than 100 ppm of alkali metals and/or alkaline earth metals, particularly less than 50 ppm of sodium oxide. The preparation of such high-purity alumino-silicates using ion exchanged ortho-silicic acid is described in German patent DE 38 39 580 - CI. The resultant alumino-silicates have the desired high purities, but they cannot be dispersed. Alumino-silicates are physically/chemically not comparable with aluminium hydroxides. For instance, their surfaces have higher acidities due to the stronger Lewis acid character of silicic acid. This property is utilized for a large number of catalytic processes, such as desulfurizing, denitrification, oxidation, hydrocracking, and mild hydrocracking. Modern catalysts often consist of many different support materials [for instance, cf. GB 2166971-C]. It is essential that the catalyst support materials be homogeneously mixed to ensure uniform compositions. Therefore, dis-persible alumino-silicates offer several advantages, e. g. when used for coating substrates. This method can be used in the field of catalysis and materials coating. The explanations given hereinabove show that there is a need for dispersible high-purity alumino-silicates. It was the object of this invention to develop a synthesis for preparing dispersible alumino-silicates which offers the following advantages: Even after drying and conversion into powder, the alumino-silicates prepared according to the present invention shall be dispersible in aqueous solutions without addition of or treatment with organic solvents. The alumino-silicates prepared according to the present invention shall have high purities. The starting materials used for preparing the aforesaid compounds shall be readily available. The price of the starting materials shall allow an economic process. The manufacturing process shall be feasible both as a continuous and discontinuous process. It was surprisingly found that the process described hereinbelow provides alumino-silicates which solve the problems the present invention was based on. According to the present invention there is provided a% process for the manufacture of alumino-silicates which are dispersible in aqueous and/or aqueous-acidic media, characterised in that (A) one or more hydrolyzable aluminum compound (s)i jg (are) hydrolyzed jointly or separately from each other in space or time, preferably jointly, for-, and (B) prior to, during, or after hydrolysis, said compound (s) (are) contacted with one or more silicic acid compound(s) as herein described and (C) after hydrolysis or also already during hydrolysis, the reaction products are jointly subjected to hydrothermal ageing in aqueous medium and in the presence of a monovalent organic C1- to C6- acid or a monovalent inorganic acid/at temperatures of 40 to 220°C for a period of 0.5 hour at 24 hours and, (D)optionally, the aforesaid products are calcined at temperature between 550 C an 1500C for period of 05 hours to 24 hours whereby the aluminum compound/ silicon compound ratio used is from 99.5 wt.%:0.5 wt.% to 70wt%:30wt%, each referring to the ratio of A12O3 : SiO2. The instant invention relates to a process for the continuous or discontinuous manufacture of high-purity alumino-silicates which can be dispersed in aqueous and/or aqueous-acidic media. The desired properties are obtained by the following process: Process for the manufacture of alumino-silicates which are dispersible in aqueous and/or aqueous-acidic media wherein (A) one or more hydrolyzable aluminium compound(s) is (are) hydro-lyzed jointly or discontinuously in space or time, preferably jointly, and (B) said compound(s) is (are) contacted with one or more silicic acid compound(s) prior to, during, or after hydrolysis, preferably prior to or during hydrolysis, and (C) the combined compounds/reaction products are jointly subjected to hydrothermal ageing in an aqueous environment and in the presence of a monovalent organic C1to C6 acid or a monovalent inorganic acid at temperatures of 40 to 220 °C for a period of more than 0.5 h during or after hydrolysis. The hydrolysis may be carried out at 20 to 98 °C, preferably 50 to 98 °C, most preferably 85 to 98 °C. Hydrolyzable aluminium compounds within the meaning of the instant invention are all the aluminium compounds forming Al-OH and/or Al-O-Al structures when reacted with water, e. g. aluminium alcoholates, aluminium hydroxyalcoholates, aluminium oxy-alcoholates, aluminium acetyl acetonates, aluminium alkyl chlorides, or aluminium carboxylates. Preferably, the hydrolyzable aluminium compounds are compounds of the type Al(O-R-A-R')3-n (O-R")n, wherein independent of each other and, optionally, different for each residue R" is a branched or an unbranched, a cyclic or an acyclic, or an aro matic hydrocarbon residue having 1 to 30, particularly 2 to 12 carbon atoms, R' is a branched or an unbranched, a cyclic or an acyclic, or an aro matic hydrocarbon residue having 1 to 10 carbon atoms, particularly an alkyl residue having 4 to 8 carbon atoms, R is a bivalent and branched or unbranched, cyclic or acyclic, or aromatic C1 to C10 hydrocarbon residue, particularly an alkyl residue having 1 to 5 carbon atoms, most preferably 1 to 3 carbon atoms, the latter one most preferably being unbranched and acyclic, A represents a heteroatom of main group 6 (oxygen group) or main group 5 (nitrogen group) of the periodic system, preferably oxygen or nitrogen, wherein, if A represents an element oi main group 5, A bears hydrogen or a Ci to Cio alkyl residue or a Ce to Cio aryl -/alkyl aryl residue as additional substituent(s) for the saturation of its valences, and n is an index for the numbers 0, 1, 2, or 3. Preferably, n is equal to 0 or equal to 3. In case n is equal to 0 and A is equal to oxygen, aluminium trisbutylene glycolates are preferred. In case n is equal to 3, the aluminium alkoxy compounds are aluminium trisalcoholates which, with increasing preference, have C2 to C12, C4 to C8, or C6 to C8 hydrocarbon residues, the residues being saturated or unsaturated, cyclic or acyclic, branched or unbranched, or aromatic, preferably saturated. Saturated, linear C6 to C8 hydrocarbon residues are particularly preferred. For example, hydrolyzable aluminium alcoholates may be prepared according to the process disclosed in EP 0 111 115 - Al. Prior to use, the hydrolyzable metal compounds may be purified by distillation, filtration, or centrifugation. In the case of silicic acid, ion exchange of metal ions, particularly sodium, preferably on exchange resins containing ammonium ions, is an efficient purification method. For the hydrothermal treatment, it is essential that an acid be present during or after hydrolysis. This acid is a monovalent organic Ci to C6 acid or a monovalent inorganic acid (or a monovalent mineral acid), such as HCl or HNO3. The acid may also be added after hydrolysis, as long as it is present during the hydrothermal treatment. According to the present invention, the acid or an acid-forming agent is added prior to the first drying of the alumino-silicate. Within the meaning of the present invention, monovalent organic Ci to Ce acids are organic compounds which have at least 1 to 6 carbon atoms and show an acid reaction in the presence of water, i.e. react as proton donators, and which can set free only one proton, referring to the acid molecule. Included in this definition are for instance acid chlorides, sulfonic acids, and other organic compounds forming -COOH or -COO" groups in water. The acid is added in quantities of 0.1 to 2.0 gram, preferably 0.2 to 0.8 gram, referring to 1 gram of solid material. Hydrothermal ageing preferably takes 1 to 22 hours. A period of 2 to 18 hours and temperatures of 80 to 130 °C have proved to be particularly efficient. It is another outstanding feature of the process according to the present invention that, apart from the educts and products, the reaction can be performed without any organic solvent and in an essentially alcoholic/ aqueous environment, an aqueous environment being preferred. The educts A12O3 and SiO2 may be used in quantities of from 99.5 wt.% : 0.5 wt.% to 70 wt.% : 30 wt.%. preferably from 98 wt.% : 2 wt.% to 70 wt.% : 30 wt.%, each referring to the ratio of A12O3 : Si02. Furthermore, the reaction product of this invention may be calcined at temperatures of 550 °C to 1,500 °C for a period of 0.5 to 24 hours. The dispersible alumino-silicates are useful as catalysts, catalyst supports for catalytic processes, for the manufacture of catalysts, as starting materials for ceramics, as coating materials, and as binder components and rheological modifiers in aqueous systems. The silicic acid compounds used according to this invention are for exam pie condensation products of orthosilicic acid, particularly the low condensation products thereof, and most preferably orthosilicic acid itself. The silicic acid compounds used according to the present invention can also be manufactured in situ by hydrolysis of silicon tetrachloride. Water is preferably used for the hydrolysis. By the term 'dispersible alumino-silicates' as used in the present inven tion are meant dry and, most expediently, powdery alumino-silicates which can be dispersed in aqueous media in quantities of at least greater than 90 wt.%, preferably greater than 95 wt.%, i.e. greater than 90 wt.%, preferably greater than 95 wt.% of said products will remain dispersed after dispersion. In the experimental part described hereinbelow a method for quantifying the dispersibility is described. The resultant aqueous products can be dried using known methods, such as spray drying or by means of a rotary drier. The process for manufacturing alumino-silicates according to this invention can be carried out continuously or discontinu-ously. The alumino-silicates of this invention can be dispersed using water-diluted acids, such as inorganic, monovalent acids, e. g. hydrochloric acid or nitric acid, o C1to C6 organic acids, monovalent acids being preferred, The acids used for dispersion can be employed in concentrations of 0.1 to 40 wt.%, referring to the straight acid. Preferably, lower concentrations are used, i. e. from 0.1 to 5 wt.%. In some cases it is also possible to use only water for dispersion. The compounds manufactured according to this invention can be calcined in a furnace at temperatures of preferably 550 °C to 1,500 °C for a period of preferably 3 to 24 hours. The metal oxide manufactured in this way has the requisite high purity. Table 1, following, shows several alumino-silicates manufactured according to the present invention and their dispersibilities D. Table 1 (Table Removed) Legend: Compounds A and B are conventionally produced alumino-silicates. C is an alumino-silicate prepared according to this invention, including hydrothermal treatment, but without addition of an acid A through C are reference substances; 10 weight percent of each solid alumino-silicate were dispersed * acid for dispersion Table 2, following, shows the physical data of the alumino-silicates according to this invention in comparison with two standard alumino-silicates (A and B). The reference alumino-silicates A and B were prepared by mixing an alumina sol with silicic acid. Table 2 (Table Removed) The dispersible alumino-silicates manufactured according to this inven tion have high purities. In particular, the content of alkali metals and alkaline earth metals which have particularly adverse effects when using the aforesaid products for catalysis is very low. The results of the trace elements analysis by ICP spectroscopy are listed in Table 3. The purities listed in Table 3 can be further increased by using bidistilled water and containers made of inert materials. Table 3 (Table Removed) Legend: The concentration of other elements, such as Pb, Zn, Ni, Cr, Cu, Mn, Mo, and Ga, is less than 50 ppm in total. Examples (General) The compounds manufactured according to this invention were analysed for trace impurities by inductively coupled plasma (ICP) spectroscopy. The surfaces were determined by the BET method, while the pore volumes were additionally determined by mercury porosirnetry (Autopore II 9220 porosimeter, Mikromeritics) and nitrogen porosirnetry (Flow Prep 060, Gemini 2360, 2375, Mikromeritics). The compounds of this invention were calcined in a muffle furnace at temperatures of between 550 °C and 1,500 °C. Deionised water was used for the hydrolysis. The dispersibility D was determined by the following method. A certain amount of the dry, solid material was placed into a beaker and mixed with dilute acid, e. g. nitric acid, while stirring. Stirring was continued for 10 minutes (stirrer speed 800 - 850 rpm). The suspension thus obtained was quantitatively transferred to the glass tube of a centrifuge. Subsequent to centrifugation for 20 minutes at 2,400 rpm1, the supernatant was decanted, and the residue in the glass tube was dried for at least 0.5 hour at 573 K (300 °C). The glass tube then was weighed including the residue, and thereafter without residue. The difference obtained is the weight of nondispersed solid. Nondispersed quantity, % = gram of residue x 100 initial weight of alumina, in grams Dispersed quantity D, % = 100 - percentage of nondispersed quantity Example 1 (Compound 1) Into a 2,000-ml three-neck flask, there were placed 487 grams of water and 87.7 grams of aqueous silicic acid (3.6 wt.%). The contents was heat ed to 75 °C. A total of 500 grams of aluminium trishexanolate (6.35 wt.% Al content) were added to this mixture in three portions at time intervals of 15 minutes each. The mixture was stirred for 30 minutes. Then, 6.3 grams of 65 % nitric acid were added. The alcohol was decanted and the residue was diluted to a desired solids content of about 5 %. The sol was heated to 95 °C and maintained at this temperature for 16 hours. The remaining aqueous phase was liberated from alcohol residue by steam distillation, followed by spray drying. Example 2 (Compound 2) Into a 2,000-ml three-neck flask, there were placed 390 grams of water and 185 grams of aqueous silicic acid (3.6 wt.%). The contents was heated to 75 °C. A total of 500 grams of aluminium trishexanolate (6.35 wt.% Al content) were added to this mixture in three portions at time intervals of 15 minutes each. The mixture was stirred for 30 minutes. Then. 6.7 grams of 65 % nitric acid were added. The alcohol was decanted and the residue was diluted to a solids content of about 5 %. The sol was heated to 95 °C and maintained at this temperature for 16 hours. The remaining aqueous phase was liberated from alcohol residue by steam distillation followed by spray drying. Example 3 (Compound 3) Into a 2,000-ml three-neck flask, there were placed 490 grams of water and 78.3 grams of aqueous silicic acid (4.0 wt.%). The contents was heat ed to 75 °C. A total of 500 grams of aluminium trishexanolate (6.3 wt.% Al content) were added to this mixture in three portions at time intervals of 15 minutes each. The mixture was stirred for 30 minutes. Then, 6.3 grams of 65 % nitric acid were added. The alcohol was decanted and the residue was diluted to a solids content of about 5 %. The sol was heated to 95 °C and maintained at this temperature for 5 hours. The remaining aqueous phase was liberated from alcohol residue by steam distillation, followed by spray drying. Example 4 (Compound 4) Into a 2,000-ml three-neck flask, there were placed 383 grams of water and 185 grams of aqueous silicic acid (3.6 wt.%). The contents was heated to 75 °C. A total of 500 grams of aluminium trishexanolate (6.35 wt.% Al content) were added to this mixture in three portions at time intervals of 1 5 minutes each. The mixture was stirred for 30 minutes. Then, 6.7 grams of 65 % nitric acid were added. The alcohol was decanted and the residue was diluted to yield a solids content of about 5 %. The sol was heated to 95 °C and maintained at this temperature for 5 hours. The remaining aqueous phase was liberated from alcohol residue by steam distillation, followed by spray drying. Example 5 (Compound 5) Into a 2,000-ml three-neck flask, there were placed 654 grams of aqueous silicic acid (3.9 wt.%) and 67 grams of nitric acid (65 wt.%). The contents was heated to 75 °C. A total of 500 grams of aluminium trishexanolate (6.3 wt.% Al content) were added to this mixture in tliree portions at time intervals of 15 minutes each. The mixture was stirred for 30 minutes. The sol was heated to 95 °C and maintained at this temperature for 5 hours, followed by dilution to a solids content of about 5 %. The supernatant alcohol was decanted and the remaining aqueous phase was liberated from alcohol residue by steam distillation, followed by spray drying. Example 6 (Compound 6) Into a 2,000-ml three-neck flask, there were placed 638 grams of aqueous silicic acid which were heated to 75 °C. A total of 500 grams of aluminium trishexanolate (6.35 wt.% Al content) were added in three portions at time intervals of 15 minutes each. The mixture was stirred for 30 minutes. The alcohol was decanted and the residue was diluted to a solids content of about 5 %. The sol was heated to 95 °C and maintained at this temperature for 5 hours. The remaining aqueous phase was liberated from alcohol residue by steam distillation, followed by spray drying. We Claim:- 1. A process for the manufacture of alumino-silicates which are dispersible in aqueous and/or aqueous-acidic media, characterised in that (A) one or more hydrolyzable aluminum compound(s) as herein described (are) hydrolyzed jointly or separately from each other, preferably jointly, and (B) prior to, during, or after hydrolysis, said compound(s) (are) contacted with one or more silicic acid compound(s) as herein described, and (C) after hydrolysis or also already during hydrolysis, the reaction products are jointly subjected to hydrothermal ageing in aqueous medium and in the presence of a monovalent organic Ci- to C6- acid or a monovalent inorganic acid as herein described at temperatures of 40 to 220°C for a period of 0.5 hour to 24 hours; and (D) optionally, the aforesaid products are calcined at temperatures between 550°C and 1500°C for a period of 0.5 hours to 24 hours. whereby the aluminum compound/silicon compound ratio used is from 99.5 wt.%:0.5 wt.% to 70wt%:30wt%, each referring to the ratio of A12O3 : SiO2. 2. A process as claimed in claim 1, wherein the hydrolyzable aluminum compounds are compounds of the type Al(O-R-A-R)3-n (O-R")n, wherein R" is a hydrocarbon residue having 1 to 30 carbon atoms, R' is a hydrocarbon residue having 1 to 10 carbon atoms, R is a bivalent hydrocarbon residue having 1 to 10 carbon atoms, and A represents a heteroatom of the main group 6 (oxygen group) or the main group 5 (nitrogen group) of the periodic system, preferably oxygen or nitrogen, wherein, if A represents an element of the main group 5, A bears hydrogen or a C1 to C10 alkyl residue or a C6 to C1o aryl-/ alkyl aryl residue as additional substituent (s) for the stauration of its valences, and n is an index for the numbers 0, 1,2, or 3. 3. A process as claimed in claim 2, wherein n is equal to 0. 4. A process as claimed in claim 2, wherein n is equal to 3. 5. A process as claimed in any one of claims 1, 2 or 4, wherein the hydrolyzable aluminum compounds are aluminum alcoholates having C2 to C12, preferably C4 to C8, most preferably saturated C6 to Cs hydrocarbon residues. 6. A process as claimed in any one of the preceding claims, wherein orthosilicic acid and/or condensation products thereof are used as the silicic acid compound. 7. A process as claimed in any one of the preceding claims, wherein the hydrolyzable metal compounds are first purified by distillation, filtration, or centrifugation. 8. A process as claimed in any one of the preceding claims, wherein the silicic acid is liberated preferably by ion exchange of metal ions as herein described preferably on exchanger resins containing ammonium ions. 9. A process as claimed in any one of the preceding claims, wherein the hydrolysisis performed at 20 to 98°C preferably 85 to 98°C. 10. A process as claimed in any one of the preceding claims, wherein the acid is added prior to, during, or after the hydrolysis and prior to the hydrothermal treatment. 11. A process as claimed in any one of claims 1 to 9, wherein the acid is added after the hydrolysis and prior to or during the hydrothermal treatment. 12. A process as claimed in any one of the preceding claims, wherien the hydrothermal ageing is conducted for a period of 2 to 18 hours. 13. A process as claimed in any one of the preceding claims, wherein the hydrothermal ageing is conducted at 80 to 130°C. 14. A process for the manufacture of alumino-silicates substantially as hereinbefore described with reference to the fore-going examples.

Documents:

603-del-1998-abstract.pdf

603-del-1998-assignment.pdf

603-del-1998-claims.pdf

603-del-1998-complete specification (granted).pdf

603-del-1998-correspondence-others.pdf

603-del-1998-correspondence-po.pdf

603-del-1998-description (complete).pdf

603-del-1998-form-1.pdf

603-del-1998-form-13.pdf

603-del-1998-form-19.pdf

603-del-1998-form-2.pdf

603-del-1998-form-3.pdf

603-del-1998-form-4.pdf

603-del-1998-form-6.pdf

603-del-1998-pa.pdf

603-del-1998-pct-210.pdf

603-del-1998-petition-137.pdf

603-del-1998-petition-138.pdf