MXPA02006585A - Synthesis of crystalline silicoaluminophosphates - Google Patents

Abstract

This invention is directed to a method of making a crystalline silicoaluminophosphate molecular sieve. Themethod includes adding to a vessel a mixture comprising a silicon containing composition, an aluminum containing composition, a phosphorus containing composition, and a template, and continuously stirring the mixture while applying heat at a temperature and duration effective to form a crystalline silicoaluminophosphate molecular sieve, wherein stirring is applied for 2095%of the duration that heat is applied. The result is a substantial increase in crystalline molecular sieve product.

Description

SYNTHESIS OF CRYSTALLINE SILICONE-ALUMINOPHOSPHATES Field of the Invention This invention relates to the synthesis of a crystalline silico-aluminophosphate (SAPO) molecular sieve. In particular, this invention relates to increasing the yield of a crystalline SAPO molecular sieve by stirring the starting materials while applying heat at a temperature and for an effective duration to form a molecular sieve of crystalline silicoaluminophosphate, where the stirring is applied by means of stirring. - 95% of the duration of that heat. BACKGROUND OF THE INVENTION Molecular sieves generally have a microporous structure and are composed of either crystalline aluminosilicates, chemically similar to clays and feldspars and belonging to a class of materials known as zeolites, or crystalline aluminophosphates derived from mixtures containing a salt of amine or organic quaternary ammonium, or crystalline silico-aluminophosphates which are made by hydrothermal crystallization from a reaction mixture comprising reactive sources of silica, alumina and phosphate. Molecular sieves have a variety of uses. They can be used to dry gases and liquids; for selective molecular separation based on polar size and properties; as exchangers of ions; as catalysts in disintegration (cracking), hydro-disintegration, disproportionation, alkylation, isomerization, oxidation, and conversion of oxygenates to hydrocarbons; as chemical carriers; in gas chromatography; and in the petroleum industry to remove normal distillate paraffins. Silico-aluminophosphate (SAPO) molecular sieves have recently become of particular interest. These molecular sieves have the ability to convert oxygenates to olefins, aromatics and other compositions. They are especially effective for converting oxygenate compositions such as methanol and dimethyl ether to olefins such as ethylene and propylene. Several methods of doing SAPOs have been reported. For example, US Patent 4,440,871 discloses a method of making a SAPO molecular sieve. The method typically involves mixing together a phosphorus-containing compound and an aluminum-containing compound until a homogeneous mixture is obtained. To the homogeneous mixture is added a template and a composition containing silica, and this mixture is stirred until a final homogeneous mixture is obtained. This final homogeneous mixture is then heated to form a crystalline SAPO molecular sieve. US Patents 4,943,424 and 5,087,347 disclose a method for making a SAPO-11 molecular sieve that is reported to exhibit unique and useful catalytic and selectivity properties. The molecular sieve is made by preparing an aqueous reaction mixture containing aluminum isopropoxide and phosphoric acid. Subsequently, the mixture is combined with silicon oxide. This mixture is then combined with an organic template to form the reaction mixture. The reaction mixture is then adjusted to pH and heated to form the crystalline molecular sieve product. The crystallization is carried out in an autoclave and without stirring. US Patent 5,663,471 discloses a method for making SAPO-34. The method includes mixing together an aluminum-containing compound, a phosphorus-containing compound, and an acid. This mixture is homogenized and a template material is added. The mixture with added template is then homogenized, and all the mixture is poured into a container. The vessel is stirred at room temperature. It is then heated to form a crystalline molecular sieve product. The product is recovered and dried. US Patent 5,324,493 discloses a method for crystallizing aluminophosphates and silico-aluminophosphates having an AEL structure using 1,2-bis- (4-pyridyl) -ethane. The method includes mixing together a reactive source of aluminum, phosphorus, and optionally, silicon, with the addition of 1,2-bis- (4-pyridyl) -ethane. The mixture is heated under autogenous pressure in a closed system to form the crystalline product. The product is isolated after the reaction, washed, and dried. The synthesis can be carried out either statically or with agitation. The known processes for making molecular sieves of silico-aluminophosphates are, unfortunately, very inefficient. tes. In some cases, less than 50% by weight of the reaction components are reacted to form the final crystallized product. The non-crystallized reaction components are typically not recovered and discarded. It is, therefore, desirable to find a reaction process that does not result in a substantial amount of waste. SUMMARY OF THE INVENTION In order to overcome the various problems associated with the manufacture of molecular sieves of crystalline silico-aluminophosphates, this invention provides a novel method of making molecular sieves of crystalline silico-aluminophosphates. The method comprises adding to a container a mixture comprising a silicon-containing composition, an aluminum-containing composition, a template, and a phosphorus-containing composition, and stirring the mixture while applying heat at effective temperature and duration to form a sieve. of crystalline silico-aluminophosphate, where the stirring is applied for 20-95% of the duration in which heat is applied. Desirably, the heat is applied at a temperature between 50 and 250 ° C. The heat can also be applied for a duration of between 10 minutes and 240 hours. Desirably, the stirring is applied of 20-90% of the duration in which heat is applied, more preferably, continuous stirring is applied of 30-80% of the duration in which heat is applied. In another embodiment, the composition that contains silicon, the aluminum-containing composition, the template, and the phosphorus-containing composition are added in effective amounts to provide a crystalline molecular sieve composition having a ratio of 0.30-0.34 Si02 / A1203 /0.82-0.86 of P205. Desirably, the template comprises tetraethyl ammonium hydroxide, most desirably, the template comprises tetraethyl ammonium hydroxide and dipropylamine. In another embodiment, the invention provides a method of making an olefin product from an oxygenate composition. The method comprises providing a crystalline silico-aluminophosphate molecular sieve made by the method of this invention, calcining the molecular sieve, and contacting the calcined molecular sieve with an oxygenate composition under conditions effective to form an olefin product. Desirably, the oxygenate composition comprises a compound selected from the group consisting of methanol; ethanol; n-propanol; isopropanol; C4-C20 alcohols; methyl ethyl ether; dimethyl ether; diethyl ether; di-isopropyl ether; formaldehyde; dimethyl carbonate; dimethyl ketone; acetic acid; and its mixtures. The olefin product is desirably contacted with a polyolefin-forming catalyst under conditions effective to form a polyolefin. Detailed Description of the Invention Silico-aluminophosphate molecular sieves (SAPO) serve as particularly desirable catalytic materials in convert oxygenate feeds to olefin compositions. They are particularly good catalysts for making olefins such as ethylene and propylene from oxygenate compounds. The molecular sieves of silico-aluminophosphates are generally classified as being micro-porous materials having ring structures of 8, 10, or 12 members. These ring structures may have an average pore size varying from about 3.5-15 Angstroms. The small pore SAPO molecular sieves having an average pore size ranging from about 3.5 to 5 Angstroms, more preferably from 4.0 to 5.0 Angstroms are preferred. These preferred pore sizes are typical of molecular sieves having 8-membered rings. In general, the molecular sieves of silico-alumino-phosphates comprise a molecular skeleton of tetrahedral units of [Si02], [A102], and [P02] that share corners. This type of skeleton is effective to convert several oxygenates to olefin products. The tetrahedral units of [P02] within the skeleton structure of the molecular sieve of this invention can be provided by a variety of compositions. Examples of these phosphorus-containing compositions include phosphoric acid, organic phosphates such as triethyl phosphate, and aluminophosphates. The phosphorus-containing compositions are they mix with reactive silicon and aluminum containing compositions under the appropriate conditions to form the molecular sieve. Tetrahedral units of [A102] within the skeletal structure of the molecular sieve of this invention can be provided by a variety of compositions. Examples of these aluminum-containing compositions include aluminum alkoxides such as aluminum isopropoxide, aluminum phosphates, aluminum hydroxide, sodium aluminate, and pseudo-boehmite. The aluminum-containing compositions are mixed with reactive silicon and phosphorus-containing compositions under the appropriate conditions to form the molecular sieve. The tetrahedral units of [SiO2] within the skeletal structure of the molecular sieve of this invention can be provided by a variety of compositions. Examples of these silicon-containing compositions include silica sols and silicon alkoxides such as tetra ethyl orthosilicate. The silicon-containing compositions are mixed with reactive phosphorus and aluminum-containing compositions under the appropriate conditions to form the molecular sieve. The substituted SAPOs can also be used in this invention. These compounds are generally known as metal-containing MeAPSOs or silico-aluminophosphates. The metal can be alkali metal ions (Group IA), alkaline earth metal ions (Group IIA), rare earth ions (Group IIIB, - ,. iiÉkkÁ¿% ». ^ s ^ .SS .. including the lanthanoid elements: lanthanum, cerium, praseodimium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium; and scandium or yttrium) and the additional transition cations of Groups IVB, VB, VIB, VIIB, VIIIB, and IB. Preferably, Me represents atoms such as Zn, Mg, Mn, Co, Ni, Ga, Fe, Ti, Zr, Ge, Sn, and Cr. These atoms can be inserted into the tetrahedral skeleton through a tetrahedral unit [Me02] . The tetrahedral unit [Me02] carries a net electric charge depending on the valence state of the substituent metal. When the metal component has a valence state of +2, +3, +4, +5, or +6, the net electric charge is between -2 and +2. Incorporation of the metal component is typically achieved by adding the metal component during molecular sieve synthesis. However, the exchange of post-synthesis ions can also be used. Suitable silico-aluminophosphate molecular sieves include SAPO-5, SAPO-8, SAPO-11, SAPO-16, SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO -36, SAPO-37, SAPO-40, SAPO-41, SAPO-42, SAPO-44, SAPO-47, SAPO-56, their metal-containing forms, and mixtures thereof. Preferred are SAPO-18, SAPO-34, SAPO-35, SAPO-44, and SAPO-47, particularly SAPO-18 and SAPO-34, including their metal-containing forms, and mixtures thereof. As used herein, the term mixture is synonymous with combination and is considered a composition of matter that has two or more components in variable proportions, regardless of their physical state. In accordance with this invention, the crystalline SAPO molecular sieves are synthesized by hydrothermal crystallization. In other words, the product of this invention is a crystalline molecular sieve which is formed by means of reacting the initiator materials under hydrothermal conditions to form the crystalline product. To significantly increase the conversion of the initiator materials to the crystalline molecular sieve product, the initiator materials are stirred during the crystallization or reaction process. Agitation can be continuous or intermittent, but it stops before the reaction process is complete. The reaction process is completed at the effective end of the crystallization, the time during which it is desirable to discontinue the application of heat. To make the crystalline silico-aluminophosphate, a reaction mixture is formed by mixing together reactive silicon, aluminum and phosphorus components together with at least one template. This is finally removed by means of calcining the crystalline product. Calcining the crystalline product means that the template essentially burns, leaving behind a structure similar to a porous tunnel within the crystalline product. Once the template is removed, the molecular sieve is described as being activated. That is, it is ready for catalytic use. ííi L? -áJi -kÉ? i? mií íimÉ i, < , ---- -j * "* -» --- "'- -» "* - -' - * - Generally, the reaction mixture is sealed and heated, preferably under autogenous pressure at a temperature of at least 50 ° C. Preferably, the reaction mixture is heated between 50 and 250 ° C, more preferably between 100 and 225 ° C. Heat is applied in an effective duration to form crystalline product.The formation of the final crystalline product can take place from around 30 minutes to as much as 2 weeks In some cases, agitation or seed formation with the crystalline material will facilitate the formation of the product.Preferably, heat is applied for a duration of between 10 minutes and 2 weeks, more preferably between 15 minutes and 240 hours, most preferably between 20 minutes and 120 hours.The mixture is stirred for a time that is less than the duration of the reaction of the components to effectively form the crystalline molecular sieve product. The duration of the reaction s e considers complete at the time that the crystallization is effectively complete. This must also correspond to the length of time that the reaction materials are heated. Agitation should be applied of 20-95% of the duration in which heat is applied, more preferably 20-90% of the duration in which heat is applied, and most preferably 30-85% of the duration in which the heat is applied. which heat is applied. In general, the degree of agitation is affected by the crystallization temperature. Typically, while the crystallization temperature is higher, the stirring time required is shorter.

Typically, the crystalline molecular sieve product will be formed in solution. It can be recovered by standard means, however, such as by centrifugation or filtration. The product can also be washed, recovered by the same means and dried. As a result of the crystallization process, the recovered screen contains within its pores at least a portion of the template used to make the initial reaction mixture. The crystalline structure is essentially wrapped around the template, and the template must be removed to obtain catalytic activity. Once the template is removed, the crystalline structure that remains has what is typically called an intracrystalline pore system. The SAPO molecular sieve may contain one or more templates. The templates are generally structure directing agents, and typically contain nitrogen, phosphorus, oxygen, carbon, hydrogen or one of their combinations, and may also contain at least one alkyl or aryl group, with 1 to 8 carbons being present in the group alkyl or aryl. Representative templates include tetraethyl ammonium salts, cyclopentylamine, aminomethyl cyclohexane, piperidine, triethylamine, cyclohexylamine, triethyl hydroxyethylamine, morpholine, dipropylamine (DPA), pyridine, isopropylamine and combinations thereof. Preferred templates are triethylamine, cyclohexylamine, piperidine, pyridine, isopropylamine, salts of j | ¿^ .S * Á $ Á? 3 ^^^ nfaaut-B-littíW tetraetil ammonium, and their mixtures. The tetraethyl ammonium salts include tetraethyl ammonium hydroxide (TEAOH), tetraethyl ammonium phosphate, tetraethyl ammonium fluoride, tetraethyl ammonium bromide, tetraethyl ammonium chloride, tetraethyl ammonium acetate. Preferred tetraethyl ammonium salts are tetraethyl ammonium hydroxide and tetraethyl ammonium phosphate. The preferred template comprises tetraethyl ammonium hydroxide, preferably tetraethyl ammonium hydroxide and dipropylamine. As is known in the art, the molecular sieve or catalyst containing the molecular sieve must be activated prior to its use in a catalytic process. The activation is carried out in such a way that the template is removed from the molecular sieve, leaving catalytically active sites with the micro-porous molecular sieve channels open for contact with the feed. The activation process is typically achieved by means of calcining, or essentially heat the template at a temperature of 200 to 800 ° C in the presence of a gas containing oxygen. In some cases, it may be desirable to heat in an environment that has a low oxygen concentration. This type of process can be used for partial or complete removal of the intra-crystalline pore system template. In other cases, particularly with smaller templates, complete or partial removal from the screen can be achieved by conventional desorption processes such as those used in making standard zeolites.

Once the molecular sieve is made, it can be mixed with other materials that provide additional hardness or catalytic activity to the finished catalyst product. When mixed, the resulting composition is typically referred to as a silico-aluminophosphate (SAPO) catalyst, with the catalyst comprising the SAPO molecular sieve. The materials that can be combined with the molecular sieve can be various inert or catalytically active materials, or various binder materials. These materials include compositions such as kaolin and other clays, various forms of rare earth metals, other catalyst components than zeolites, catalyst components of zeolite, alumina or alumina sol, titania, zirconia, quartz, silica or silica sol. , and its mixtures. These components are also effective in reducing the overall cost of the catalyst, acting as a heat shield to help heat protect the catalyst during regeneration, densify the catalyst and increase the strength of the catalyst. When mixed with molecular sieve materials that are not silico-aluminophosphate, the amount of molecular sieve that is contained in the final catalyst product varies from 10 to 90 percent of the total catalyst, preferably from 30 to 70 percent of the total catalyst . The molecular sieve synthesized according to the present method can be used to dry gases and liquids; for selective molecular separation based on size and polar properties; as an ion exchanger; as a catalyst in disintegration, hydro-disintegration, disproportionation, alkylation, isomerization, oxidation, and conversion of oxygenates to hydrocarbons; as a chemical carrier; in gas chromatography; and in the petroleum industry to remove normal distillate paraffins. It is particularly suitable for use as a catalyst in disintegration, hydro-disintegration, disproportionation, alkylation, isomerization, oxidation, and conversion of oxygenates to hydrocarbons. More particularly, the molecular sieve is suitable for use as a catalyst in the conversion of oxygenates to hydrocarbons. In its most preferred embodiment, the SAPO molecular sieve is used as a catalyst in the conversion of oxygenates to hydrocarbons. In this process a feed containing an oxygenate makes contact with the crystalline molecular sieve in a reaction zone of a reactor at effective conditions to produce light olefins, particularly ethylene and propylene. Typically, the oxygenate feed is contacted with the catalyst when the oxygenate is in a vapor phase. Alternatively, the process may be carried out in a liquid phase or a mixed vapor / liquid phase. When the process is carried out in a liquid phase or in a mixed vapor / liquid phase, different conversions and selectivities of feed to product may result depending on the catalyst and the reaction conditions. As used herein, the reactor term includes not only commercial scale reactors but also pilot size reactor units and laboratory scale reactor units. Olefins can generally be produced over a wide range of temperatures. An effective operating temperature range can be around 200 to 700 ° C. At the low end of the temperature range, the formation of the desired olefin products can become markedly slow. At the upper end of the temperature range, the process may not form an optimal amount of product. An operating temperature of at least 300 °, and up to 500 ° C is preferred. The process can be carried out in a dynamic bed system or any system using a variety of transport beds, although a fixed bed system can be used. It is particularly desirable to operate the reaction process at high velocity spaces. The conversion of oxygenates to produce olefins is preferably carried out in a large-scale catalytic reactor. This type of reactor includes fluid bed reactors and concurrent riser reactor reactors as described in "Free Fall Reactor", Fluidization Engineering, D. Kunii and 0. Levenspiel, Robert E. Krieger Publishing Co. , NY, 1977, incorporated herein by reference in its entirety. Additionally, countercurrent free fall reactors can be used in the conversion process. See, for example, US-A-4, 068, 136 and "Riser Reactor", Fluidization and Fluid-Parti Systems, pp. 48-59, F. A. Zenz and D. F. Othmo, Reinhold Publishing Corp, NY, 1960, the descriptions of which are expressly incorporated herein by reference. Any standard commercial scale reactor system can be used, however, including fixed bed or moving bed systems. Commercial-scale reactor systems can be operated at a space hourly speed by weight (WHSV) of 1 hr "1 to 1,000 hr" 1. In the case of commercial scale reactors, WHSV is defined as the weight of hydrocarbons in the feed per hour by weight of the molecular sieve content of silico-aluminophosphate of the catalyst. The content of hydrocarbons will be oxygenated and any hydrocarbon that is optionally combined with the oxygenates. The molecular sieve content of silico-aluminophosphate is intended to mean only the molecular sieve portion of silico-alumino-phosphate that is contained within the catalyst. This excludes components such as binders, thinners, inerts, rare earth components, etc. It is highly desirable to operate at a temperature of at least 300 ° C and a Normalized Temperature Corrected Methane Sensitivity (TCNMS) of less than about 0.016, preferably less than about 0.012, more preferably less than about 0.01. It is particularly preferred that the reaction conditions for making olefins from The Oxygenates comprise a WHSV of at least 20 hr 1 producing olefins and a TCNMS of less than about 0.016. As used herein, TCNMS is defined as the Normalized Methane Selectivity (NMS) when the temperature is less than 400 ° C. The NMS is defined as the production of methane product divided by the production of ethylene product where each production is measured in, or converted to, a base of% by weight. When the temperature is 400 ° C or higher, the TCNMS is defined by the following equation, where T is the average temperature inside the reactor in ° C: NMS TCNMS = 1+ (((T-400) / 400) xl4.84) The pressure can also vary over a wide range, including autogenous pressures. Preferred pressures are in the range of about 5 kPa to about 5 MPa, with the most preferred range being between about 50 kPa to about 0.5 Mpa. The above pressures are exclusive of any spent oxygen diluent, and thus, they refer to the partial pressure of the oxygenated compounds and / or their mixtures with feed. One or more inert diluents may be present in the feed, for example, in an amount of 1 to 95 molar percent, based on the total number of moles of all feed components and diluents fed into the feed zone. ^ i I .. - ^ il. * ^ .. i ... - "? - * > ^" ~~ .. ^ A * L¿. & reaction (or catalyst). Typical diluents include, but are not necessarily limited to, helium, argon, nitrogen, carbon monoxide, carbon dioxide, hydrogen, water, paraffins, alkanes (especially methane, ethane, and propane), alkyols, aromatics, and mixtures thereof . Preferred diluents are water and nitrogen. Water can be injected in either liquid or vapor form. The process can be carried out in a batch, semi-continuous or continuous manner. The process can be conducted in a simple reaction zone or in a number of reaction zones arranged in series or in parallel. The level of conversion of oxygenates can be maintained to reduce the level of unwanted by-products. The conversion can also be maintained high enough to avoid the need for commercially undesirable levels of recycling of unreacted feeds. A reduction in unwanted by-products is observed when the conversion moves from 100 mole% to about 98 mole% or less. The recycling of as much as around 50 mole% of the feed is commercially acceptable. Therefore, conversion levels reaching both targets are from about 50 mole% to about 98 mole% and, desirably, from about 85 mole% to about 98 mole%. However, it is also acceptable to achieve conversion between 98% molar and 100% molar to simplify the recycling process. Oxygenate conversion can ááá iM 'jfahÜilttftl I Ünj "-" ""' -'- -i "" - - - '- - - -. * - ... ~. . ... ^ .- * t .. * e. tÉ »m *? H? > M * .M * ..- stay at this level using a number of familiar methods for technical people in the field. Examples include, but are not necessarily limited to, adjusting one or more of the following: the reaction temperature; Pressure; flow rate (ie, WHSV); level and degree of catalyst regeneration; amount of re-circulation of the catalyst; the specific configuration of the reactor; the composition of the diet; and other parameters that affect the conversion. If regeneration is required, the molecular sieve catalyst can be continuously introduced as a moving bed to a regeneration zone where it can be regenerated, such as, for example, by removal of carbon materials or by oxidation in an oxygen-containing atmosphere. In a preferred embodiment, the catalyst is subjected to a regeneration step by burning accumulated carbon deposits during the conversion reactions. The oxygenate feed comprises at least one organic compound containing at least one oxygen atom, such as aliphatic alcohols, ethers, carbonyl compounds (aldehydes, ketones, carboxylic acids, carbonates, esters and the like). When the oxygenate is an alcohol, the alcohol may include an aliphatic portion having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms. Representative alcohols include but are not necessarily limited to minor straight and branched chain aliphatic alcohols and their Hálá.A ??? ? . ^ Í..C-- í ...- * - -,., ... i- »^« a. ~ ^ M ¿... j- u. ^? _ ^ ???? A t unsaturated counterparts. Examples of suitable oxygenates include, but are not limited to: methanol; ethanol; n-propanol, - isopropanol; C4-C20 alcohols; methyl ethyl ether; dimethyl ether; diethyl ether; di-isopropyl ether; formaldehyde; dimethyl carbonate; dimethyl ketone; acetic acid; and its mixtures. Preferred oxygenates are methanol, dimethyl ether, or a mixture thereof. The method of making the preferred olefin product in this invention may include the additional step of making these compositions from hydrocarbons such as petroleum, coal, tar, slate, biomass and natural gas. Methods for making the compositions are known in the art. These methods include fermentation to alcohol or ether, making synthesis gas, then converting the synthesis gas to alcohol or ether. The synthesis gas can be produced by known processes such as steam reforming, auto-thermal reforming and partial oxidation. One skilled in the art will also appreciate that the olefins produced by the conversion reaction of oxygenates to olefins of the present invention can be polymerized to form polyolefins, particularly polyethylene and polypropylene. Processes for forming polyolefins from olefins are known in the art. Catalytic processes are preferred. Particularly preferred are the metallocene, Ziegler-Natta and acid catalyst systems. See, for example, patents ta »US Nos. 3,258,455; 3,305,538; 3,364,190; 5,892,079; 4,659,685; 4,076,698; 3,645,992; 4,302,565; and 4,243,691, the descriptions of the catalysts and processes of each one being expressly incorporated herein by reference. In general, these methods involve contacting the olefin product with a polyolefin-forming catalyst at an effective pressure and temperature to form the polyolefin product. A preferred polyolefin-forming catalyst is a metallocene catalyst. The preferred temperature operating range is between 50 and 240 ° C and the reaction can be carried out under pressure, low, medium or high, being anywhere within the range of 1 to 200 bar. For processes carried out in solution, an inert diluent can be used, and the preferred operating pressure range is between 10 and 150 bar, with a preferred temperature range between 120 and 230 ° C. For gas phase processes, it is preferred that the temperature is generally within a range of 60 to 160 ° C, and that the operating pressure is between 5 and 50 bar. In addition to the polyolefins, numerous other olefin derivatives can be formed from olefins recovered from this invention. These include, but are not limited to, aldehydes, alcohols, acetic acid, linear alpha-olefins, vinyl acetate, ethylene dichloride and vinyl chloride, ethylbenzene, ethylene oxide, eumeno, isopropyl alcohol, acrolein, allyl chloride, propylene oxide, acrylic acid, ethylene-propylene rubbers, and acrylonitrile, and trimers and dimers of ethylene, propylene or butylenes. The methods for manufacturing these derivatives are well known in the art, and therefore, are not discussed herein. This invention will be better understood with reference to the following examples, which are intended to illustrate specific embodiments within the overall scope of the invention as claimed. Comparative Examples A Al. Static Synthesis Without Seed An alumina slurry was prepared by mixing together 68.06 parts of Condea Pural Alumina SB and 110.15 parts of distilled water. To this mixture was added a solution containing 115.74 parts of phosphoric acid (85% by weight ACROS), using 24.9 parts of rinse water, and mixed until it became homogeneous. Then 22.50 parts of Ludox AS40 (40% by weight of SiO2) were added using 10.20 parts of rinse water, and the mixture was stirred until it became homogeneous. To the homogeneous mixture were added 183.31 parts of a 40% by weight solution of tetraethyl ammonium hydroxide (TEAOH, Eastern Chemical), using 43.17 parts of rinse water. The gel was mixed until homogeneous and 80.79 parts of dipropylamine (DPA) were added using 26.27 parts of rinse water. When the mixture became visually homogeneous, 237.2 parts were transferred to a stainless steel autoclave, heated in 2 hours jjA Ml- ^ fcl-iÉ ^^ I-llÉlli - ^ MfcMil'Mfírilllífr ^ i ^ -Mflí l'l "'¡í -' -rT- * -S ^. ^ t - ^ ^^; faith: - ^ ^^^ - ugly »ai-Í & -, & ^ * .. ^» «a ^ a & 175 ° C, and kept at this temperature for 60 hours A2.Static Synthesis with Seed A 433.7 parts of the mixture made in Al were added 2.78 parts of a slurry containing 6.4% by weight of chabasite crystals.The mixture was stirred until it became homogeneous.Then, 181.5 parts of the gel were transferred to a stainless steel autoclave , they were heated in 2 hours at 175 ° C, and kept at this temperature for 60 hours .. A3 Synthesis "Wobbled" with Seed 98.9 parts of the homogeneous mixture obtained in Al were transferred to another stainless steel autoclave. mounted on the shaft inside a stove and wobbled at 60 rpm, heated in two hours at 175 ° C, and kept at this temperature for 60 hours, with continuous stirring through the heating process. Molar fractions of the synthesis mixtures described in A1-A3 were as follows: 0.3 Si02 / A1203 / P205 / TEAOH / 1.6 DPA / 52 H20 After the indicated crystallization time, the solids were recovered quantitatively from the mother liquid by centrifugation. The washed solids were dried at 120 ° C, and an XRD pattern was recorded. The results of A1-A3 are summarized in Table 1.

Table 1 * Production is expressed as the dry product recovered per 100 g of heated synthesis mixture These results indicate that agitation through the heating process reduces the production of recovered product, even for seed synthesis mixtures. Comparative Examples B Bl. Agitated Synthesis with Seed A mixture with seed having approximately the same molar composition as in Al was prepared in a manner similar to A2. The mixture was heated in 8 hours at 175 ° C in a 2 liter stainless steel Parr autoclave. The mixture was then stirred at 144 rpm using a combination of a Parr anchor and helix mixing blades. The mixing was continued throughout the hydrothermal treatment for 60 hours at 175 ° C. The solids were recovered from the mother liquor by centrifugation, washed and dried. The dry product production was 7.5% by weight of pure SAPO-34. B2. Static Synthesis with Seed A mixture with seed was prepared as in Bl. Mix I YES «A ¡Alt A. i attai. static (without stirring) was heated for 60 hours at 175 ° C. From this synthesis, 12.5% by weight of pure SAPO-34 was recovered. Examples 1 and 2 Two mixtures having approximately the same molar composition as in Comparative Examples Al and B2 were prepared. The mixtures were heated in an autoclave having the same volume, the same mixing blades, etc. as in Example B2. (Example 1) The first mixture was heated in 8 hours to 165 ° C and maintained for 5 hours at 165 ° C under continuous agitation at 80 rpm. The stirring was then stopped, but the heating was continued for an additional 19 hours. After crystallization (ie, at the end of the heating process) 13.4% by weight of pure SAPO-34 was recovered. (Example 2) The second mixture was heated in 8 hours at 175 ° C and maintained for 5 hours at 175 ° C under continuous stirring. The stirring was then stopped, but heating continued for an additional 5 hours. After crystallization, 12.3% by weight of pure SAPO-34 was recovered. Examples 1 and 2 illustrate the advantage of semi-static synthesis (ie, stirring for less than the entire duration of heating) for SAPO-34. Example 3 A mixture having approximately the same composition molar fraction that in Comparative Example Al was prepared. The mixture was heated to 170 ° C in 12 hours in a commercial scale unit with continuous stirring. The unit was maintained at 170 ° C for 54 hours with continuous stirring, then the stirring was stopped. The production at this point was about 11% by weight of crystalline molecular sieve. After the stirring was stopped, the unit was maintained at 170 ° C for an additional 10 hours, at which time the crystallization effectively ceased. At this point, the production was approximately 13% by weight. Example 4 A mixture having approximately the same molar composition as Comparative Example Al was prepared. The mixture was heated to 170 ° C in 11 hours in a commercial unit with continuous agitation. The unit was maintained at 170 ° C for 30 hours with continuous stirring, then stirring was stopped. The production at this point was about 11.8% by weight of crystalline molecular sieve. After the stirring was stopped, the unit was maintained at 170 ° C for an additional 10 hours, at which time the crystallization effectively ceased. At this point, the production was approximately 13% by weight. Having now fully described the invention, it will be appreciated by those skilled in the art that the invention can be carried out within a wide range of parameters within what is claimed, without departing from the spirit and scope of the invention.

Claims (11)

1. CLAIMS 1. A method for making a crystalline silicoaluminophosphate molecular sieve comprising adding to a container a mixture comprising a silicon-containing composition, an aluminum-containing composition, a template, and a phosphorus-containing composition, and stirring the mixture while heat is applied at an effective temperature and duration to form a silico-aluminophosphate molecular sieve, where agitation is applied at 20-95% of the duration at which heat is applied.
2. 2. The method of claim 1, wherein the heat is applied at a temperature between 50 and 250 ° C.
3. 3. The method of any of the preceding claims, wherein the heat is applied for a duration of between 10 minutes and 240 hours.
4. 4. The method of any of the preceding claims, wherein the stirring is applied at 20-90% of the duration in which heat is applied.
5. The method of any of the preceding claims, wherein the stirring is applied at 30-85% of the duration in which heat is applied.
6. The method of any of the preceding claims, wherein the silicon-containing composition, the aluminum-containing composition, the template, and the phosphorus-containing composition are added in effective amounts to provide a molecular sieve composition having a ratio of 0.30-0.34 SiO2 / Al203 / 0.82-0.86 P205.
7. The method of any of the preceding claims, wherein the template comprises tetraethyl ammonium hydroxide.
8. The method of any of the preceding claims, wherein the template comprises tetraethyl ammonium hydroxide and dipropylamine.
9. 9. A method of making an olefin product from an oxygenate composition, comprising: providing a crystalline silico-aluminophosphate to molecular sieve made by the method of any of claims 1-8, and contacting the calcined molecular sieve with an oxygenate composition under effective conditions to form an olefin product. The method of claim 9, wherein the oxygenate composition comprises a compound selected from a group consisting of methanol; ethanol; n-propanol; isopropanol; C4-C20 alcohols; methyl ethyl ether; dimethyl ether; diethyl ether; di-isopropyl ether; formaldehyde; dimethyl carbonate; dimethyl ketone; acetic acid; and its mixtures. The method of claim 9 or 10, wherein the olefin product is contacted with a polyolefin-forming catalyst under effective conditions to form k ^ ??. a? ^ i. i < -.i? í. .... S.3 -.... H. .Aijfci.i a polyolefin.