JPH0339007B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new method for the production of molecular sieves, and more specifically to crystalline borosilicate AMS.
-1B Concerns a new method for producing molecular sieves and the products made by the method. Zeolite materials, both natural and synthetic, are known to have catalytic capabilities for many hydrocarbon processes. Zeolitic materials are typically crystalline aluminum silicates with aligned pores having a defined structure containing pores interconnected by channels. The pores and passageways throughout the crystalline material are generally uniform in size, allowing selective separation of hydrocarbons. Therefore, these materials are often known in the art as "molecular sieves" and are used for certain catalytic properties in addition to selective adsorption processes. is influenced to some extent by the size of the molecules that selectively enter the crystal structure and presumably contact active catalytic reaction sites within the arrays of these materials. In general, the term "molecular sieve" includes a wide range of natural and synthetic cation-containing crystalline zeolite materials. It is generally characterized as a crystalline aluminum silicate containing a network of SiO ₄ and AlO ₄ tetrahedrons, in which silicon and aluminum atoms are cross-linked by sharing oxygen atoms. The negative charge of the framework resulting from the substitution of aluminum atoms for silicon atoms is due to positive ions, such as alkali metal cations, or alkaline earth metal cations, ammonium ions,
or hydrogen ions, the balance is maintained. Boron is not considered a replacement for aluminum or silicon in zeolite compositions. However, recently, new crystalline borosilicate molecular sieves
AMS-1B is US Pat. No. 4,268,420 and No. 4,269,813.
Nos. 1 and 2, which are incorporated herein by reference. According to these patents, AMS−
1B can be synthesized by crystallizing a silicon oxide source; boron oxide; sodium oxide; and an organic template compound such as a tetra-n-propylammonium salt. To form the catalytically active species of AMS-1B, sodium ions are typically removed by one or more exchanges with ammonium ions followed by calcination. Another method of producing borosilicate molecular sieves uses a combination of sodium hydroxide and aqueous ammonia as an organic template compound, as disclosed in U.S. Pat. No. 4,285,919, incorporated herein by reference. and the use of high concentrations of amines such as hexamethylene diamine as described in German Patent No. 2830787. UK patent no.
No. 2024790 discloses the formation of borosilicate using ethylene diamine with sodium hydroxide. Aluminosilicates have been made with low sodium content using diamines containing four or more carbon atoms as described in European Published Patent Applications No. 669 and No. 11362. US Pat. No. 4,139,600 and US Pat. No. 4,151,189 describe a method for making aluminosilicate molecular sieves with low sodium content using diamines or _C2 - _C5 alkyl amines. The method of producing AMS-1B crystalline borosilicate molecular sieves with low sodium content is desirable in that an exchange step for removing sodium is not required. Additionally, AMS-1B with a higher boron content than normally produced by conventional techniques.
The method for producing crystalline borosilicates is also highly advantageous. Additionally, a method of making AMS-1B crystalline borosilicate without the addition of alkali or ammonium hydroxide would be desirable. Furthermore, products formed in such a manner that exhibit superior activity over conventionally produced materials would also be highly advantageous. The present invention provides silicon oxides, boron oxides, alkylammonium cations or precursors thereof,
and ethylenediamine under crystallization conditions in the substantial absence of metal hydroxide and ammonium hydroxide. , as well as products formed by such methods. Traditionally, AMS-1B borosilicate molecular sieves are made from boron oxides, silicon oxides, and organic templates.
It is made by crystallizing an aqueous mixture of compounds in the presence of an alkali metal hydroxide, usually sodium hydroxide. When such a mixture is crystallized, the resulting AMS-1B molecular sieve contains an alkali metal ion, usually a sodium ion, which balances the negative charge of the backbone caused by the substitution of boron for silicon in the crystalline sieve structure. Contains. However, when used in catalytic applications, the presence of sodium ions is usually detrimental. Typically, AMS-
The hydrogen form of 1B is created by exchange with ammonium ions followed by drying and calcination. The present invention is a method for directly crystallizing low sodium content AMS-1B molecular sieves, using less expensive alkylammonium template compounds than in conventional manufacturing methods. In another aspect of the invention, the AMS-1B crystalline borosilicate can be formed with a higher boron content than would normally be formed using conventional techniques. Yet another aspect of the invention provides that metal hydroxide and ammonium hydroxide-free and AMS
-1B is a product formed by a process in which crystalline borosilicate is formed from an aqueous mixture with a low water to silica ratio. According to the present invention, AMS-1B crystalline molecular sieves process an aqueous mixture containing sources of boron oxide, silicon oxide, tetraalkylammonium compounds, and ethylene diamine in the substantial absence of metal hydroxides and ammonium hydroxide. It is formed by crystallization under Typically, the molar ratios of the various reactants can be varied to produce the crystalline borosilicate of the present invention.
In particular, the molar ratio of initial reactant concentrations of silica to boron oxide can range from about 2 to about 400;
Preferably from about 4 to about 150, most preferably from about 5 to about 80. The molar ratio of water to silica can range from about 2 to about 500, preferably from about 5 to about 60, and most preferably from about 10 to about 35. It has been found that production with water to silica molar ratios of about 10 to about 15 is particularly preferred. The molar ratio of ethylenediamine to silicon oxide used in the preparation of AMS-1B crystalline borosilicate according to the present invention should be greater than about 0.05, typically less than about 5, preferably about
0.1 to about 1.0, most preferably about 0.2 to about 0.5. The molar ratio of alkylammonium template compound or precursor thereof to silicon oxide useful in the preparation of the present invention ranges from 0 to about 1 or more, typically about
It can be greater than 0.005, preferably in the range of about 0.01 to about 0.1, most preferably about 0.02 to about 0.05. AMS-1B crystalline borosilicate molecular sieves formed using the method of the present invention in mixtures with low water to silica ratios are surprisingly effective in hydrocarbon conversions, such as in the conversion of ethylbenzene. It was discovered that the catalyst showed higher catalytic activity. AMS-1B crystalline borosilicate compositions exhibiting exceptional conversion activity are characterized by an initial reactant molar ratio of water to silica of from about 5 to about
25, preferably about 10 to about 22, most preferably about
10 to about 15 can be made by crystallizing a mixture of silicon oxide, boron oxide, alkylammonium compound, and ethylene diamine. Additionally, preferred initial reactant molar ratios of silica to boron oxide range from about 4 to about 150, more preferably from about 5 to about 80, and most preferably from about 5 to about 20. The molar ratio of ethylenediamine to silicon oxide used in the preparation of AMS-1B crystalline borosilicate according to the present invention should be greater than about 0.05, typically less than about 5, and preferably from about 0.1 to about 1.0, and most preferably from about 0.2 to about 0.5. The molar ratio of alkylammonium template compound or precursor to silicon oxide useful in the preparation of the present invention ranges from 0 to about 1 or more, typically greater than about 0.05, and preferably about 0.01 to about 0.1, and most preferably about 0.01
from about 0.1, and most preferably from about 0.02 to about
It is 0.05. The preferred amount of alkylammonium template compound used in the preparation of the present invention is AMS using an alkali metal cationic base conventionally.
It is noted that this is substantially less than the amount required to make −1B. This reduction in the amount of alkylammonium compound used substantially lowers manufacturing costs. The amount of alkylammonium template compound used in the preparation of this invention is inversely proportional to the amount of ethylenediamine used. If an alkylammonium compound is not used, preparation using ethylenediamine in a molar ratio of greater than about 1 to silica usually results in the formation of highly crystalline borosilicate molecular sieves. If the molar ratio is less than about 1, partially crystalline materials are formed; if the molar ratio is less than about 0.5, an amorphous product is obtained. However, if the alkylammonium compound is included in the preparation using less than about 1 molar ratio of ethylenediamine to silica, crystalline AMS-1B borosilicate is formed. As the proportion of ethylenediamine decreases, the proportion of alkylammonium compounds may generally increase. However, no hydroxides, such as in the form of alkali metal hydroxides or alkaline earth metal hydroxides or ammonium hydroxide, are used in any of the preparations of the present invention. However, it may be present in substantial amounts as an impurity in the starting reagent. By adjusting the amount of boron oxide (expressed as B ₂ O ₃ ) in the reaction mixture,
The molar ratio of SiO ₂ /B ₂ O ₃ (silica/boria) can be varied, although in many cases an excess of boron oxide is used in the preparation. AMS-1B crystalline borosilicate molecular sieves usually have the X-ray pattern and composition prescription (for oxides) shown in the table; 0.9±0.2M _2/o O:B ₂ O ₃ :ySiO ₂ :zH ₂ O, where M is at least one cation, n is the valence of that cation, and y is between 4 and about 600;
z is between 0 and about 160.

【table】

[Table] By conventional technique using sodium hydroxide
It has been discovered that AMS-1B products sometimes contain searlesite, especially when the concentration of reactants in the crystallization mixture is high. but,
AMS-1B crystalline borosilicate can be made in accordance with the present invention using higher than conventional concentrations of reactants without the formation of sialicite.
Moreover, production at higher concentrations of reactants produces crystalline borosilicates with increased activity in some hydrocarbon conversion processes. Additionally, production with high reactant concentrations is more economically efficient. More specifically, the materials of the invention contain ethylene diamine, a boron oxide source, and optionally tetra-n in water (preferably distilled or demineralized water).
- produced by mixing an organic template compound such as propylammonium bromide. The order of addition is usually not critical, although a typical procedure is to dissolve the ethylene diamine and boric acid in water and then add the template compound. Generally, the silicon oxide compound is added with intensive mixing, such as in a Waring blender. The resulting slurry is transferred to a closed crystallization vessel for an appropriate period of time. After crystallization, the resulting crystalline product can be filtered, washed with water, dried and calcined. During manufacture, acidic conditions should be avoided.
Advantageously, the PH of the reaction diameter is between about 8 and about 12;
Most preferred is between about 9 and about 10.5. PH depends on the concentration of ethylenediamine. Examples of silicon oxides useful in the present invention include silicic acid, sodium silicates, tetraalkyl silicates, and stabilized polymers of silicic acid manufactured by Ludtux, EI DuPont. Typically, the boron oxide source is boric acid, although equivalent species such as sodium borate and other boron-containing compounds can also be used. The AMS-1B crystalline borosilicate made according to the present invention does not require alkali metal cations and therefore does not require an ion exchange step before being formulated into a catalyst composition, making it similar to silicon compounds and boron oxides. It is advantageous for the starting material to contain as few alkali metal ions as possible as contaminants. Organic template compounds useful in the preparation of AMS-1B crystalline borosilicate include alkylammonium cations or precursors thereof, such as tetraalkylammonium compounds. Useful organic template compounds include tetra-n-propylammonium bromide and tetra-n-
Contains propylammonium hydroxide. In a more detailed description of the representative process of the present invention, ethylenediamine and boric acid (H ₃ BO ₃ )
an appropriate amount of is dissolved in distilled or demineralized water,
An organic template compound is then added. The resulting slurry is transferred to a closed crystallization vessel and allowed to react for a time sufficient to permit crystallization, usually at a pressure of at least the vapor pressure of water, which time ranges from about 100°C to about Usually about 0.25 to about 20 days, typically about 1 10 days, preferably from about 2 days to about 7 days. The crystallization material can be stirred as in a rockerbomb. Preferably, the crystallization temperature is kept below the decomposition temperature of the organic template compound. Particularly preferred conditions are approximately
Crystallization takes about 2 to 4 days at 145°C. Samples of the material can be removed during crystallization for examination of crystallinity and determination of optimal crystallization time. The crystalline material formed can be separated and recovered by well known methods such as overwashing. The material is exposed to temperatures ranging from several hours to several days, typically at approx.
It can be dried gently at 25-200°C to form a dry cake, which can then be ground into a powder or pellets, extruded, pelletized, or formed into a form suitable for the intended use. Let's do it. Typically, the material obtained after gentle drying contains organic template compounds and water of hydration within the solid mass, and it is desired to remove this material from the final product. requires a subsequent activation or calcination step. Typically, the gently dried product is calcined at a temperature between about 260°C and about 850°C, preferably between about 525°C and about 600°C. extreme =
Calcination temperatures or long crystallization times may prove detrimental to the crystal structure and may destroy it as a whole. Generally, it is not necessary to increase the calcination temperature above about 600°C to remove organic material from the initially formed crystalline material. Typically, molecular sieve materials are heated to about 145°C - 165°C.
Dry for about 16 hours under forced ventilation, then at a temperature increase of 125°C per hour until the temperature reaches about 540°C.
It is baked in air so that the temperature does not exceed ℃. Baking at this temperature usually lasts about 4 to 16 hours. Catalytically active materials can be deposited onto the borosilicate structure by ion exchange, impregnation, combinations thereof, or other suitable methods. Preferred substituting cations are those that catalytically activate the crystalline borosilicate, especially for hydrocarbon conversion. Typical catalytically active ions are hydrogen, B of the periodic table,
Includes metal ions of groups A, B, A, and manganese, vanadium, chromium, uranium, and rare earth elements. Also, water-soluble salts of catalytically active substances can be impregnated onto the crystalline borosilicate of the present invention. Such catalytically active substances include hydrogen, B of the periodic table,
A, B, A, B, B, and groups include metals and rare earth elements. In another aspect of the invention, catalytically active materials can be placed on top of the borosilicate structure by incorporating such catalytically active materials during initial crystallization. Generally, the same elements that can be ion-exchanged or impregnated can be loaded onto the molecular sieve structure in this way. Specific metal ions that can be added in this way include Ni,
Contains Co, Mn, V, Ti, Cu, Zn, Mo, and Zr ions. Ion exchange and impregnation techniques are well known in the art. Typically, the aqueous solution of cationic species is exchanged one or more times at about 25°C to about 100°C. on this borosilicate or on a composition consisting of a crystalline borosilicate suspended and dispersed throughout a substrate of a carrier material such as a porous refractory inorganic oxide such as alumina. Suitable catalyst compositions are often obtained by impregnation with catalytically active substances. A combination of ion exchange and impregnation can be used. The presence of sodium ions in the composition is usually detrimental to catalyst activity. AMS-1B-based catalyst compositions useful in xylene isomerization are based on hydrogen-type molecular sieves or those made by ion exchange with nickel nitrate or impregnation with ammonium molybdate. can do. The amount of catalytically active material deposited on the AMS-1B borosilicate varies from less than 1% to about 30% by weight, typically from about 0.05% to about 25% by weight, depending on the intended use process. It can vary within the range. Optimal amounts can be readily determined by routine experimentation. The AMS-1B crystalline borosilicate useful in the present invention may be incorporated into a catalyst or adsorbent as a pure substance, or may be mixed with or combined with a variety of binders or base materials depending on the intended use. It may also be mixed into. Crystalline borosilicates are active or inactive substances, synthetic or naturally occurring zeolites,
It can also be combined with inorganic or organic substances useful for caking the borosilicate.
Well-known substances are silica, silica-alumina,
including alumina, alumina sol, hydrated alumina, clays such as bentonite or kaolin, or other binders well known to those skilled in the art. Typically,
The borosilicate is incorporated into the base material by kneading it with the sol of the base material and gelling the resulting mixture. Additionally, the solid particles of borosilicate and the base material can be physically mixed. Typically,
Such borosilicate compositions can be pelletized or extruded into their use form. The crystalline borosilicate content can vary up to 100% by weight of the total composition. Catalyst composition is approximately 0.1% by weight
from about 100% by weight of the crystalline borosilicate material, typically from about 2% to about 65% by weight.
This type of material can be included. Catalytic compositions comprising the crystalline borosilicate material of the present invention and a suitable substrate material are formed by adding the microcrystalline borosilicate and the catalytically active metal compound to an aqueous sol or gel of the substrate material. can be done. The resulting mixture is thoroughly kneaded and gelled, typically by adding a substance such as aqueous ammonia. The resulting gel can be dried and calcined to form a composition in which the crystalline borosilicate and the catalytically active compound are distributed throughout the substrate material. Specific details of catalyst preparation are described in US Pat. No. 4,268,420. The invention is illustrated by, but not limited to, the following examples and comparative experiments. Examples - A series of reaction mixtures were made by dissolving ethylene diamine, boric acid, and tetra-n-propylammonium bromide (TPABr) in distilled water. While stirring the mixture in a Waring blender at maximum speed, an amount of Ludox ( _SiO2 : 40% by weight) was rapidly added and stirring continued for about 10 minutes. The resulting mixture was loaded into a stirred autoclave and digested at 145°C. After crystallization of the mixture, the product obtained was filtered, washed with distilled water, dried at 130°C overnight and heated to 530°C for 4 hours with planned preheating at a temperature increase not exceeding 125°C/hour. So〓
Baked. The product was analyzed by X-ray diffraction and elemental analysis. The product characterized as AMS-1B had the same X-ray diffraction pattern and elemental analysis indicating boron contamination as obtained in Table 1. Details of their preparation and analysis are summarized in Table 1. The catalyst composition was prepared by dispersing the calcined molecular sieve described above in PHF-alumina, which is originally an acetic acid stabilized gamma alumina hydrosol containing about 9.8% by weight Al ₂ O ₃ . Ten
g of calcined molecular sieves were added and thoroughly mixed with 405 g of alumina hydrosol. The mixture was gelled (solidified) by adding 60 ml of concentrated aqueous ammonia. The resulting solid was dried overnight in a forced air bath at 130°C.
The dried solid was calcined at 530° C. according to the above program. The baked solid was crushed and classified into 18 to 40 meshes (US sieve series). 5 g of 18-40 mesh catalyst in a 0.5 inch (1.27 cm) inner diameter tubular reactor at 399°C and 165 psig (11.6 Kg/cmG) pressure for 2 hours with a hydrogen flow of 0.3 SCF (8.50) per hour. The sample was placed in a microaromatics testing apparatus which had been pre-conditioned. The xylene isomerization test results are shown in Table 1.

【table】

【table】

[Table] Results ⁽¹⁾

Claims (1)

[Scope of Claims] 1. An aqueous mixture containing an oxide of silicon, an oxide of boron, ethylenediamine in a molar ratio to silica of greater than about 0.05, and, optionally, an alkylammonium cation or a precursor of an alkylammonium cation. under crystallization conditions in the substantial absence of metal hydroxide and ammonium hydroxide,
A method for producing AMS-1B crystalline borosilicate molecular sieve. 2 Alkylammonium cation is tetra-n
- The method of claim 1, wherein the propylammonium cation. 3 The molar ratio of alkylammonium cation or its precursor to silica is about 0.005 and about 1.0.
The method of claim 1, wherein the molar ratio of silica to boron oxide is between about 2 and about 400, and the molar ratio of water to silica is between about 2 and about 500. 4 Alkylammonium cation is tetra-n
- The method of claim 3, wherein the propylammonium cation. 5. The method of claim 1, 2, 3 or 4, wherein the boron oxide source is boric acid. 6 The molar ratio of tetra-n-propylammonium cation or precursor to silica is about 0.01 to about 0.1, the molar ratio of ethylenediamine to silica is about 0.1 to about 1.0, and the molar ratio of silica to boron oxide is about 5 to about 80, and the molar ratio of water to silica is about 5 to about 60.
The method according to claim 2, wherein: 7 The molar ratio of ethylenediamine to silica is about 0.2 to about 0.5, the molar ratio of tetra-n-propylammonium cation or precursor to silica is about 0.02 to about 0.05, and the molar ratio of water to silica is about 10 to about 0.5. 7. The method of claim 6, wherein the method is about 35. 8. The method of claim 6, wherein the molar ratio of water to silica is about 10 to 15. 9. The method of claim 1, wherein the catalytically active material is placed on the borosilicate. 10. The method of claim 1, wherein the crystallization mixture is maintained at about 125°C to about 200°C for about 1 day to about 10 days. 11. The method of claim 1, wherein the molecular sieve is incorporated into a suitable substrate material. 12. The method of claim 11, wherein the substrate material is silica, silica-alumina, or alumina. 13. The method of claim 1, wherein ions of nickel, cobalt, manganese, vanadium, titanium, copper, zinc, molybdenum, or zirconium are incorporated into the crystallization mixture. 14 Silicon oxide, boron oxide, ethylenediamine with a molar ratio of more than about 0.05 to silica,
and, optionally, an aqueous mixture containing an alkylammonium cation or a precursor thereof,
reacting under crystallization conditions in the substantial absence of metal hydroxide and ammonium hydroxide, wherein the molar ratio of silica to boron oxide is from about 4 to about 150; The molar ratio of water to silica is about 5 to 25.
A method for producing AMS-1B crystalline borosilicate molecular sieve. 15 The molar ratio of water to silica is about 10 to about
22. The method of claim 14, wherein the method is: 16 The molar ratio of alkylammonium cation or precursor to silica is about 0.01 to about 0.1
16. The method of claim 14 or claim 15, wherein the molar ratio of ethylenediamine to silica is from about 0.1 to about 1.0. 17 Alkylammonium cation is tetra-
15. The method of claim 14, wherein the n-propylammonium cation is n-propylammonium cation. 18 Alkylammonium cation is tetra-
16. The method of claim 15, wherein the n-propylammonium cation is n-propylammonium cation. 19 The molar ratio of tetra-n-propylammonium cation to silica is about 0.01 to about 0.1
19. The method of claim 18, wherein the molar ratio of silica to boron oxide is from about 5 to about 80, and the molar ratio of ethylenediamine to silica is from about 0.1 to about 1.0. 20 The molar ratio of water to silica is about 10 to about
15. The method of claim 19, wherein the method is: 21 The molar ratio of tetra-n-propylammonium cation to silica is about 0.02 to about 0.05
19. The method of claim 18, wherein the molar ratio of silica to boron oxide is from about 5 to about 20, and the molar ratio of ethylenediamine to silica is from about 0.2 to about 0.5. 22 The molar ratio of water to silica is about 10 to about
15. The method of claim 21, wherein the method is: 23 The boron oxide source is boric acid and tetra-n-
The propylammonium cation source is tetra-n-
22. The method of any one of claims 17, 18, 19, or 21, wherein propylammonium bromide is propylammonium bromide.