High charge density metallophosphate molecular sieves

Abstract

A new family of highly charged crystalline microporous metallophosphate molecular sieves designated MeAPO-81 has been synthesized. These metallophosphates are represented by the empirical formula of:
R.sup.p+.sub.rA.sup.+.sub.mM.sup.2+.sub.xE.sub.yPO.sub.z
where A is an alkali metal such as potassium, R is at least one quaternary ammonium cation of which one must be a cyclic diquaternary organoammonium cation such as N,N,N,N-tetramethyl-N,N-butano-1,6-hexanediammonium, M is a divalent metal such as zinc and E is a trivalent framework element such as aluminum or gallium. The MeAPO-81 family of materials has the BPH topology. The MeAPO-81 family of materials is among the first MeAPO-type molecular sieves to be stabilized by combinations of alkali and organoammonium cations, enabling unique high charge density compositions. The MeAPO-81 family of molecular sieves has catalytic properties for carrying out various hydrocarbon conversion processes and separation properties for separating at least one component.

Claims

1. A microporous crystalline metallophosphate material having a three-dimensional framework of [M.sup.2+O.sub.4/2].sup.2, [EO.sub.4/2].sup. and [PO.sub.4/2].sup.+ and tetrahedral units and an empirical composition in the as synthesized form and on an anhydrous basis expressed by an empirical formula of:
R.sup.p+.sub.rA.sup.+.sub.mM.sup.2+.sub.xE.sub.yPO.sub.z where R is at least one quaternary organoammonium cation of which there must be at least one cyclic diquaternary organoammonium cation, the organoammonium cations selected from the group consisting of N,N,N,N-tetramethyl-N,N-p-xyleno-1,6-hexanediammonium, N,N,N,N-tetramethyl-N,N-butano-1,6-hexanediammonium, N,N,N,N-tetramethyl-N,N-hexano-1,6-hexanediammonium, N,N,N,N-tetraethyl-N,N-hexano-1,5-pentanediammonium, N,N,N,N-tetramethyl-N,N-m-xyleno-1,6-hexanediammonium, N,N,N,N-tetramethyl-N,N-o-xyleno-1,2-ethylenediammonium, N,N,N,N-tetramethyl-N,N-butano-1,2-ethylenediammonium, N,N,N,N-tetramethyl-N,N-butano-1,2-ethylenediammonium, tetramethylammonium (TMA.sup.+), ethyltrimethylammonium (ETMA.sup.+), diethyldimethylammonium (DEDMA.sup.+), methyltriethylammonium (MTEA.sup.+), dipropyldimethylammonium (DPDMA.sup.+), tetraethylammonium (TEA.sup.+), tetrapropylammonium (TPA.sup.+), tetrabutylammonium (TBA.sup.+) and mixtures thereof, r is the mole ratio of R to P and has a value of about 0.04 to about 1.0, p is the weighted average valence of R and varies from 1 to 2, A is an alkali metal selected from the group consisting of Li.sup.+, Na.sup.+, K.sup.+, Rb.sup.+ and Cs.sup.+ and mixtures thereof, m is the mole ratio of A to P and varies from 0.1 to 1.0, M is a divalent element selected from the group of Zn, Mg, Co, Mn and mixtures thereof, x is the mole ratio of M to P and varies from 0.2 to about 0.9, E is a trivalent element selected from the group consisting of aluminum and gallium and mixtures thereof, y is the mole ratio of E to P and varies from 0.1 to about 0.8 and z is the mole ratio of O to P and has a value determined by the equation:
z=(m+p.Math.r+2.Math.x+3.Math.y+5)/2 and is characterized in that it has the x-ray diffraction pattern having at least the d-spacings and intensities set forth in Table A: TABLE-US-00006 TABLE A 2 d() I/I.sub.0 % 6.83-6.64 12.94-13.30 m-s 7.69-7.49 11.48-11.80 vs-vs 10.12-10.02 8.73-8.82 w 13.24-13.01 6.68-6.80 w-m 14.90-14.63 5.94-6.05 w-m 15.48-15.34 5.72-5.77 w-m 16.70-16.45 5.305-5.385 w 18.99-18.67 4.67-4.75 w-m 20.31-20.07 4.37-4.42 m-s 21.32-21.01 4.165-4.225 m-s 23.97-23.64 3.71-3.76 w-m 24.33-24.00 3.655-3.705 m-vs 26.71-26.35 3.335-3.38 m 27.51-27.00 3.24-3.30 w-m 27.68-27.25 3.22-3.27 w-m 28.78-28.31 3.10-3.15 w-m 29.86-29.50 2.99-3.025 m-s 30.38-29.96 2.94-2.98 m-s 30.70-30.27 2.91-2.95 m 33.60-33.03 2.665-2.71 m 34.13-33.73 2.625-2.655 m 35.35-34.84 2.537-2.573 w-m.

2. The metallophosphate material of claim 1 where A is potassium.

3. The metallophosphate material of claim 1 where E is aluminum.

4. The metallophosphate material of claim 1 where R is at least N,N,N,N-tetramethyl-N,N-p-xyleno-1,6-hexanediammonium.

5. The metallophosphate material of claim 1 where R is at least N,N,N,N-tetramethyl-N,N-butano-1,6-hexanediammonium.

6. The metallophosphate material of claim 1 where R is at least N,N,N,N-tetrmaethyl-N,N-hexano-1,6-hexanediammonium.

7. A crystalline modified form of the crystalline microporous metallophosphate of claim 1, comprising a three-dimensional framework of [M.sup.2+O.sub.4/2].sup.2, [EO.sub.4/2].sup. and [PO.sub.4/2].sup.+ tetrahedral units and derived by modifying the crystalline microporous metallophosphate of claim 1, the modifications including calcination, ammonia calcinations, ion-exchange, or any combination thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) Applicants have prepared a family of high charge density crystalline microporous metallophosphate compositions with the BPH topology, designated MeAPO-81. Compared to other early MeAPO materials, described in U.S. Pat. No. 4,567,029, the MeAPO-81 family of materials contains much more M.sup.2+ and exhibits high framework (FW) charge densities that unlike these other MeAPOs, use alkali cations in addition to organoammonium ions to balance the FW charge. The instant microporous crystalline material (MeAPO-81) has an empirical composition in the as-synthesized form and on an anhydrous basis expressed by the empirical formula:
R.sup.p+.sub.rA.sup.+.sub.mM.sup.2+.sub.xE.sub.yPO.sub.z
where A is at least one alkali cation and is selected from the group of alkali metals. Specific examples of the A cations include but are not limited to lithium, sodium, potassium, rubidium, cesium and mixtures thereof. R is at least one quaternary ammonium cation, of which at least one of the quaternary ammonium cations must be a cyclic diquaternary ammonium cation, examples of which include but are not limited to N,N,N,N-tetramethyl-N,N-p-xyleno-1,6-hexanediammonium, N,N,N,N-tetramethyl-N,N-butano-1,6-hexanediammonium, N,N,N,N-tetrmaethyl-N,N-hexano-1,6-hexanediammonium, N,N,N,N-tetraethyl-N,N-hexano-1,5-pentanediammonium, N,N,N,N-tetramethyl-N,N-m-xyleno-1,6-hexanediammonium, N,N,N,N-tetramethyl-N,N-o-xyleno-1,2-ethylenediammonium, N,N,N,N-tetramethyl-N,N-butano-1,2-ethylenediammonium, N,N,N,N-tetramethyl-N,N-butano-1,2-ethylenediammonium, tetramethylammonium (TMA.sup.+), ethyltrimethylammonium (ETMA.sup.+), diethyldimethylammonium (DEDMA.sup.+), methyltriethylammonium (MTEA.sup.+), dipropyldimethylammonium (DPDMA.sup.+), tetraethylammonium (TEA.sup.+), tetrapropylammonium (TPA.sup.+), tetrabutylammonium (TBA.sup.+) and mixtures thereof, r is the mole ratio of R to P and varies from about 0.04 to about 1.0, while p is the weighted average valence of R and varies from about 1 to 2. M and E are tetrahedrally coordinated and in the framework, M is a divalent element selected from the group of Zn, Mg, Co, Mn and mixtures thereof, while E is a trivalent element selected from aluminum and gallium and mixtures thereof. The value of m is the mole ratio of A to P and varies from 0.1 to about 1.0, x is mole ratio of M to P and varies from 0.2 to about 0.9, while the ratio of E to P is represented by y which varies from about 0.10 to about 0.8. Lastly, z is the mole ratio of 0 to E and is given by the equation:
z=(m+r.Math.p+2.Math.x+3.Math.y+5)/2.

(2) When only one type of R organoammonium cation is present, then the weighted average valence is just the valence of that cation, e.g., +1 or +2. When more than one R cation is present, the total amount of R is given by the equation:
R.sub.r.sup.p+=R.sub.r1.sup.(p1)++R.sub.r2.sup.(p2)++R.sub.r3.sup.(p3)++ . . .
the weighted average valence p is given by:

(3) $p=\frac{r1.Math.p1+r2.Math.p2+r3.Math.p3+\mathrm{.Math.}}{r1+r2+r3+\mathrm{.Math.}}$

(4) It has also been noted that in the MeAPO-81 materials of this invention that a portion of M.sup.2+ may also reside in the pores, likely in a charge balancing role.

(5) The microporous crystalline metallophosphate MeAPO-81 is prepared by a hydrothermal crystallization of a reaction mixture prepared by combining reactive sources of R, A, E, phosphorous and M. A preferred form of the MeAPO-81 materials is when E is Al. The sources of aluminum include but are not limited to aluminum alkoxides, precipitated aluminas, aluminum metal, aluminum hydroxide, aluminum salts, alkali aluminates and alumina sols. Specific examples of aluminum alkoxides include, but are not limited to aluminum ortho sec-butoxide and aluminum ortho isopropoxide. Sources of phosphorus include, but are not limited to, orthophosphoric acid, phosphorus pentoxide, and ammonium dihydrogen phosphate. Sources of M include but are not limited to zinc acetate, zinc chloride, zinc oxide, cobalt acetate, cobalt chloride, magnesium acetate, magnesium nitrate, manganese sulfate, manganese acetate and manganese nitrate. Sources of the other E elements include but are not limited to precipitated gallium hydroxide, gallium chloride, gallium sulfate or gallium nitrate. Sources of the A metals include the halide salts, nitrate salts, hydroxide salts, acetate salts, and sulfate salts of the respective alkali metals. R is at least one quaternary organoammonium cation where at least one of the organoammonium cations is a cyclic diquaternary organoammonium cation, the quaternary ammonium cations selected from the group consisting of N,N,N,N-tetramethyl-N,N-p-xyleno-1,6-hexanediammonium, N,N,N,N-tetramethyl-N,N-butano-1,6-hexanediammonium, N,N,N,N-tetrmaethyl-N,N-hexano-1,6-hexanediammonium, N,N,N,N-tetraethyl-N,N-hexano-1,5-pentanediammonium, N,N,N,N-tetramethyl-N,N-m-xyleno-1,6-hexanediammonium, N,N,N,N-tetramethyl-N,N-o-xyleno-1,2-ethylenediammonium, N,N,N,N-tetramethyl-N,N-butano-1,2-ethylenediammonium, N,N,N,N-tetramethyl-N,N-butano-1,2-ethylenediammonium, tetramethylammonium (TMA.sup.+), ethyltrimethylammonium (ETMA.sup.+), diethyldimethylammonium (DEDMA.sup.+), methyltriethylammonium (MTEA.sup.+), dipropyldimethylammonium (DPDMA+), tetraethylammonium (TEA), tetrapropylammonium (TPA.sup.+), tetrabutylammonium (TBA.sup.+) and mixtures thereof, and the sources include the hydroxide, chloride, bromide, iodide and fluoride compounds. Specific examples include without limitation N,N,N,N-tetramethyl-N,N-p-xyleno-1,6-hexanediammonium dibromide, N,N,N,N-tetramethyl-N,N-p-xyleno-1,6-hexanediammonium dihydroxide, N,N,N,N-tetramethyl-N,N-butano-1,6-hexanediammonium dibromide, N,N,N,N-tetrmaethyl-N,N-hexano-1,6-hexanediammonium dibromide, tetrapropylammonium hydroxide, methyltriethylammonium hydroxide, tetraethylammonium hydroxide, and tetrabutylammonium hydroxide. In one embodiment R is a combination of N,N,N,N-tetramethyl-N,N-p-xyleno-1,6-hexanediammonium and TPA.sup.+. In another embodiment, R is a combination of N,N,N,N-tetramethyl-N,N-butano-1,6-hexanediammonium and TPA.sup.+. In yet another embodiment, R is a combination of N,N,N,N-tetramethyl-N,N-hexano-1,6-hexanediammonium and TPA.sup.+.

(6) The reaction mixture containing reactive sources of the desired components can be described in terms of molar ratios of the oxides by the formula:
aR.sub.2/pO: bA.sub.2O: cMO:E.sub.2O.sub.3:dP.sub.2O.sub.5:eH.sub.2O
where a varies from about 2.1 to about 100, b varies from about 0.1 to about 8, c varies from about 0.25 to about 8, d varies from about 1.69 to about 25, and e varies from 30 to 5000. If alkoxides are used, it is preferred to include a distillation or evaporative step to remove the alcohol hydrolysis products. The reaction mixture is now reacted at a temperature of about 60 to about 200 C. and preferably from about 95 to about 175 C. for a period of about 1 day to about 3 weeks and more preferably for a time of about 1 day to about 7 days in a sealed reaction vessel at autogenous pressure. After crystallization is complete, the solid product is isolated from the heterogeneous mixture by means such as filtration or centrifugation, and then washed with deionized water and dried in air at ambient temperature up to about 100 C. MeAPO-81 seeds can optionally be added to the reaction mixture in order to accelerate or otherwise enhance the formation of the desired microporous composition.

(7) A favored approach to MeAPO-81 synthesis is the Charge Density Mismatch Approach, which has been applied to the synthesis of aluminosilicate zeolites, as outlined in U.S. Pat. No. 7,578,993 and in CHEM. MATER., 2014, 26, 6684-6694. It is applied to metalloaluminophosphates for the first time here. Metalloaluminophosphate solutions are prepared with excess phosphate and large, low charge density SDAs, such as TPAOH, TEAOH, and TBAOH, which are then perturbed by the addition of small amounts of alkali and cyclic diquaternary organoammonium to induce crystallization under the synthesis conditions. The method has advantages in expense and efficiency because the non-commercially available cyclic diquaternary organoammonium cations can be utilized in small amounts and they don't have to be converted to the hydroxide form, an additional expensive step, for use.

(8) The MeAPO-81 metallophosphate-based material, which is obtained from the above-described process, is characterized by the x-ray diffraction pattern, having at least the d-spacings and relative intensities set forth in Table A below.

(9) TABLE-US-00002 TABLE A 2 d() I/I.sub.0 % 6.83-6.64 12.94-13.30 m-s 7.69-7.49 11.48-11.80 vs-vs 10.12-10.02 8.73-8.82 w 13.24-13.01 6.68-6.80 w-m 14.90-14.63 5.94-6.05 w-m 15.48-15.34 5.72-5.77 w-m 16.70-16.45 5.305-5.385 w 18.99-18.67 4.67-4.75 w-m 20.31-20.07 4.37-4.42 m-s 21.32-21.01 4.165-4.225 m-s 23.97-23.64 3.71-3.76 w-m 24.33-24.00 3.655-3.705 m-vs 26.71-26.35 3.335-3.38 m 27.51-27.00 3.24-3.30 w-m 27.68-27.25 3.22-3.27 w-m 28.78-28.31 3.10-3.15 w-m 29.86-29.50 2.99-3.025 m-s 30.38-29.96 2.94-2.98 m-s 30.70-30.27 2.91-2.95 m 33.60-33.03 2.665-2.71 m 34.13-33.73 2.625-2.655 m 35.35-34.84 2.537-2.573 w-m

(10) The MeAPO-81 material may be modified in many ways to tailor it for use in a particular application. Modifications include calcination, ammonia calcinations, ion-exchange, steaming, various acid extractions, ammonium hexafluorosilicate treatment, or any combination thereof, some of which are outlined for the case of UZM-4 in U.S. Pat. No. 6,776,975 B1 which is incorporated by reference in its entirety. In addition, properties that may be modified include porosity, adsorption, framework composition, acidity, thermal stability, ion-exchange capacity, etc.

(11) As synthesized, the MeAPO-81 material will contain some of the exchangeable or charge balancing cations in its pores. These exchangeable cations can be exchanged for other cations, or in the case of organic cations, they can be removed by heating under controlled conditions. Because MeAPO-81 is a large pore material, the BPH structure has 12-ring pores along the c-axis, many organic cations may be removed directly by ion-exchange, heating may not be necessary. If heating is required to remove the organic cations from the pores, a preferred method is ammonia calcination. Calcination in air converts the organic cations in the pores to protons, which can lead to the loss of some metal, for Example Al, from the framework upon exposure to ambient atmospheric water vapor. When the calcination is carried out in an ammonia atmosphere, the organic cation in the pore is replaced by NH.sub.4.sup.+ cation and the framework remains intact (see STUDIES IN SURFACE SCIENCE, (2004) vol. 154, p. 1324-1331). Typical conditions for ammonia calcinations include the use of gaseous anhydrous ammonia flowing at a rate of 1.1 Umin while ramping the sample temperature at 5 C./min to 500 C. and holding at that temperature for a time ranging from 5 minutes to an hour. The resulting ammonium/alkali form of MeAPO-81 has essentially the diffraction pattern of Table A. Once in this form, the ammonia calcined material may be ion-exchanged with H.sup.+, NH.sub.4.sup.+, alkali metals, alkaline earth metals, transition metals, rare earth metals, or any mixture thereof, to achieve a wide variety of compositions with the MeAPO-81 framework in superior condition.

(12) When MeAPO-81 or its modified forms are calcined in air, there can be a loss of metal from the framework, such as Al, which can alter the x-ray diffraction pattern from that observed for the as-synthesized MeAPO-81 (see STUDIES IN SURFACE SCIENCE, (2004) vol. 154, p. 1324-1331). Typical conditions for the calcination of the MeAPO-81 sample include ramping the temperature from room temperature to a calcination temperature of 400 to 600 C., preferably a calcination temperature of 450 to 550 C. at a ramp rate of 1 to 5 C./min, preferably a ramp rate of 2 to 4 C./min, the temperature ramp conducted in an atmosphere consisting either of flowing nitrogen or flowing clean dry air, preferably an atmosphere of flowing nitrogen. Once at the desired calcination temperature, if the calcination atmosphere employed during the temperature ramp is flowing clean dry air, it may remain flowing clean dry air. If the calcination atmosphere during the ramp was flowing nitrogen, it may remain flowing nitrogen at the calcination temperature or it may be immediately converted to clean dry air; preferably at the calcination temperature the calcination atmosphere will remain flowing nitrogen for a period of 1 to 10 hours and preferably for a period of 2 to 4 hours before converting the calcination atmosphere to flowing clean dry air. The final step of the calcination is a dwell at the calcination temperature in clean dry air. Whether the calcination atmosphere during the initial temperature ramp was flowing nitrogen or flowing clean dry air, once at the calcination temperature and once the calcination atmosphere is clean dry air, the MeAPO-81 sample will spend a period of 1 to 24 hours and preferably a period of 2 to 6 hours under these conditions to complete the calcination process.

(13) The crystalline MeAPO-81 materials of this invention can be used for separating mixtures of molecular species, removing contaminants through ion exchange and catalyzing various hydrocarbon conversion processes. Separation of molecular species can be based either on the molecular size (kinetic diameter) or on the degree of polarity of the molecular species.

(14) Methods used to exchange one cation for another are well known in the art and involve contacting the microporous compositions with a solution containing the desired cation (at molar excess) at exchange conditions. Exchange conditions include a temperature of about 15 C. to about 100 C. and a time of about 20 minutes to about 50 hours. Although not preferred, the organic cation can first be removed by heating under controlled conditions.

(15) The MeAPO-81 compositions of this invention can also be used as a catalyst or catalyst support in various hydrocarbon conversion processes. Hydrocarbon conversion processes are well known in the art and include cracking, hydrocracking, alkylation of both aromatics and isoparaffin, isomerization, polymerization, reforming, hydrogenation, dehydrogenation, transalkylation, dealkylation, hydration, dehydration, hydrotreating, hydrodenitrogenation, hydrodesulfurization, methanol to olefins, methanation and syngas shift process. Specific reaction conditions and the types of feeds which can be used in these processes are set forth in U.S. Pat. Nos. 4,310,440, 4,440,871 and 5,126,308, which are incorporated by reference. Preferred hydrocarbon conversion processes are those in which hydrogen is a component such as hydrotreating or hydrofining, hydrogenation, hydrocracking, hydrodenitrogenation, hydrodesulfurization, etc.

(16) Hydrocracking conditions typically include a temperature in the range of 400 to 1200 F. (204 to 649 C.), preferably between 600 and 950 F. (316 and 510 C.). Reaction pressures are in the range of atmospheric to about 3,500 psig (24,132 kPag), preferably between 200 and 3000 psig (1379 and 20,685 kPag). Contact times usually correspond to liquid hourly space velocities (LHSV) in the range of about 0.1 to 15 hr.sup.1, preferably between about 0.2 and 3 hr.sup.1. Hydrogen circulation rates are in the range of 1,000 to 50,000 standard cubic feet (scf) per barrel of charge (178 to 8,888 std. m.sup.3/m.sup.3), preferably between 2,000 and 30,000 scf per barrel of charge (355 and 5,333 std. m.sup.3/m.sup.3). Suitable hydrotreating conditions are generally within the broad ranges of hydrocracking conditions set out above.

(17) The reaction zone effluent is normally removed from the catalyst bed, subjected to partial condensation and vapor-liquid separation and then fractionated to recover the various components thereof. The hydrogen, and if desired some or all of the unconverted heavier materials, are recycled to the reactor. Alternatively, a two-stage flow may be employed with the unconverted material being passed into a second reactor. Catalysts of the subject invention may be used in just one stage of such a process or may be used in both reactor stages.

(18) Catalytic cracking processes are preferably carried out with the MeAPO-81 composition using feedstocks such as gas oils, heavy naphthas, deasphalted crude oil residua, etc. with gasoline being the principal desired product. Temperature conditions of 850 to 1100 F. (455 to 593 C.), LHSV values of 0.5 to 10 hr.sup.1 and pressure conditions of from about 0 to 50 psig (0 to 345 kPa) are suitable.

(19) Alkylation of aromatics usually involves reacting an aromatic (C.sub.2 to C.sub.12), especially benzene, with a monoolefin to produce a linear alkyl substituted aromatic. The process is carried out at an aromatic:olefin (e.g., benzene:olefin) ratio of between 5:1 and 30:1, a LHSV of about 0.3 to about 6 hr.sup.1, a temperature of about 100 to about 250 C. and pressures of about 200 to about 1000 psig (1,379 to 6,895 kPa). Further details on apparatus may be found in U.S. Pat. No. 4,870,222 which is incorporated by reference.

(20) Alkylation of isoparaffins with olefins to produce alkylates suitable as motor fuel components is carried out at temperatures of 30 to 40 C., pressures from about atmospheric to about 6,894 kPa (1,000 psig) and a weight hourly space velocity (WHSV) of 0.1 to about 120 hi.sup.1. Details on paraffin alkylation may be found in U.S. Pat. Nos. 5,157,196 and 5,157,197, which are incorporated by reference.

(21) The conversion of methanol to olefins is effected by contacting the methanol with the MeAPO-81 catalyst at conversion conditions, thereby forming the desired olefins. The methanol can be in the liquid or vapor phase with the vapor phase being preferred. Contacting the methanol with the MeAPO-81 catalyst can be done in a continuous mode or a batch mode with a continuous mode being preferred. The amount of time that the methanol is in contact with the MeAPO-81 catalyst must be sufficient to convert the methanol to the desired light olefin products. When the process is carried out in a batch process, the contact time varies from about 0.001 hour to about 1 hour and preferably from about 0.01 hour to about 1.0 hour. The longer contact times are used at lower temperatures while shorter times are used at higher temperatures. Further, when the process is carried out in a continuous mode, the Weight Hourly Space Velocity (WHSV) based on methanol can vary from about 1 to about 1000 hr.sup.1 and preferably from about 1 to about 100 hr.sup.1.

(22) Generally, the process must be carried out at elevated temperatures in order to form light olefins at a fast enough rate. Thus, the process should be carried out at a temperature of about 300 to about 600 C., preferably from about 400 to about 550 C. and most preferably from about 450 to about 525 C. The process may be carried out over a wide range of pressure including autogenous pressure. Thus, the pressure can vary from about 0 kPa (0 psig) to about 1724 kPa (250 psig) and preferably from about 34 kPa (5 psig) to about 345 kPa (50 psig).

(23) Optionally, the methanol feedstock may be diluted with an inert diluent in order to more efficiently convert the methanol to olefins. Examples of the diluents which may be used are helium, argon, nitrogen, carbon monoxide, carbon dioxide, hydrogen, steam, paraffinic hydrocarbons, e. g., methane, aromatic hydrocarbons, e. g., benzene, toluene and mixtures thereof. The amount of diluent used can vary considerably and is usually from about 5 to about 90 mole percent of the feedstock and preferably from about 25 to about 75 mole percent.

(24) The actual configuration of the reaction zone may be any well known catalyst reaction apparatus known in the art. Thus, a single reaction zone or a number of zones arranged in series or parallel may be used. In such reaction zones the methanol feedstock is flowed through a bed containing the MeAPO-81 catalyst. When multiple reaction zones are used, one or more MeAPO-81 catalysts may be used in series to produce the desired product mixture. Instead of a fixed bed, a dynamic bed system, e. g., fluidized or moving, may be used. Such a dynamic system would facilitate any regeneration of the MeAPO-81 catalyst that may be required. If regeneration is required, the MeAPO-81 catalyst can be continuously introduced as a moving bed to a regeneration zone where it can be regenerated by means such as oxidation in an oxygen containing atmosphere to remove carbonaceous materials.

(25) The following examples are presented in illustration of this invention and are not intended as undue limitations on the generally broad scope of the invention as set out in the appended claims. The products of this invention are designated with the general name MeAPO-81, with the understanding that all of the MeAPO-81 materials exhibit a structure with the BPH topology.

(26) The structure of the MeAPO-81 compositions of this invention was determined by x-ray analysis. The x-ray patterns presented in the following examples were obtained using standard x-ray powder diffraction techniques. The radiation source was a high-intensity, x-ray tube operated at 45 kV and 35 mA. The diffraction pattern from the copper K-alpha radiation was obtained by appropriate computer based techniques. Flat compressed powder samples were continuously scanned at 2 to 56 (2). Interplanar spacings (d) in Angstrom units were obtained from the position of the diffraction peaks expressed as where is the Bragg angle as observed from digitized data. Intensities were determined from the integrated area of diffraction peaks after subtracting background, I.sub.o being the intensity of the strongest line or peak, and I being the intensity of each of the other peaks.

(27) As will be understood by those skilled in the art the determination of the parameter 20 is subject to both human and mechanical error, which in combination can impose an uncertainty of about 0.4 on each reported value of 20. This uncertainty is, of course, also manifested in the reported values of the d-spacings, which are calculated from the 20 values. This imprecision is general throughout the art and is not sufficient to preclude the differentiation of the present crystalline materials from each other and from the compositions of the prior art. In some of the x-ray patterns reported, the relative intensities of the d-spacings are indicated by the notations vs, s, m, and w which represent very strong, strong, medium, and weak, respectively. In terms of 100I/I.sub.o, the above designations are defined as:
w=0-15;m=15-60: s=60-80 and vs=80-100

(28) In certain instances the purity of a synthesized product may be assessed with reference to its x-ray powder diffraction pattern. Thus, for example, if a sample is stated to be pure, it is intended only that the x-ray pattern of the sample is free of lines attributable to crystalline impurities, not that there are no amorphous materials present.

(29) In order to more fully illustrate the invention, the following examples are set forth. It is to be understood that the examples are only by way of illustration and are not intended as an undue limitation on the broad scope of the invention as set forth in the appended claims.

Examples 1-3

(30) Examples 1-3 cover the synthesis of the cyclic diquats structure directing agents SDA1, SDA2 and SDA3 that are utilized in the Charge Density Mismatch syntheses of MeAPO-81 in Examples 4-6.

Example 1: Synthesis of SDA1

N,N,N,N-tetramethyl-N,N-p-xyleno-1,6-hexanediammonium dibromide

(31) ##STR00001##

(32) A 50.00 g portion of , dibromo-p-xylene (Sigma-Aldrich) was placed in a 1-liter beaker and dissolved in 550 ml dry tetrahydrofuran (THF) using a stirbar. The resulting solution was transferred to a 1 liter 3-neck round bottom flask equipped with an overhead stirrer, a heating mantle and a reflux condenser. Separately, 33.31 g N,N,N,N-tetramethyl-1,6-hexanediamine (99%, Sigma-Aldrich) was diluted with 32.50 g THF and placed in a pressure-equalizing dropping funnel that was attached to one of the necks of the round bottom flask. The amine solution was then added dropwise to the dibromide solution in the flask with stirring. Some solid formation was observed during the addition. Upon completion of the addition, the dropping funnel was removed and a thermocouple connected to a temperature controller was inserted into the flask. After stirring for 15 minutes, the reaction mixture was heated to 64 C. and held at that temperature for 42 hours. The reaction was allowed to cool and the solid product was isolated by filtration under a nitrogen blanket. The solid was washed with ether and filtered under nitrogen blanket before residual solvent was removed using a vacuum oven. The identity of cyclic diquat SDA1, N,N,N,N-tetramethyl-N,N-p-xyleno-1,6-hexanediammonium dibromide, in which two dimethyl-substituted quaternized N-atoms are attached by 1) a (CH.sub.2).sub.6 chain and 2) a p-xylyl group, was confirmed by .sup.13C nmr as there was excellent agreement between observed and calculated nmr line positions.

Example 2: Synthesis of SDA2

N,N,N,N-tetramethyl-N,N-butano-1,6-hexanediammonium dibromide

(33) ##STR00002##

(34) A 85.00 g portion N,N,N,N-tetramethyl-1,6-hexanediamine (99%) was diluted in 500 ml dry tetrahydrofuran (THF) in 1-liter beaker using a stirbar. The resulting solution was transferred to a 1 liter 3-neck round bottom flask equipped with an overhead stirrer, a heating mantle and a reflux condenser. Separately, 106.51 g 1,4-dibromobutane (99.1%, Sigma-Aldrich) was placed in a pressure-equalizing dropping funnel that was attached to one of the necks of the round bottom flask. The dibromide was then added to the amine solution in the flask in a dropwise fashion with stirring. The reaction mixture remained a solution over the course of the addition. Upon completion of the addition, the dropping funnel was removed and a thermocouple connected to a temperature controller was inserted into the flask. After stirring for 30 minutes, there was no visible reaction, the reaction mixture was still a solution. The reaction mixture was heated to 64 C. and held at that temperature for 24 hours. Solid formation in the reaction mixture started to become visible once the reaction reached 40 C. Once completed, the reaction was allowed to cool and the solid product was isolated by filtration under a nitrogen blanket. The solid was washed with ether and filtered under nitrogen blanket before residual solvent was removed using a vacuum oven. The identity of cyclic diquat SDA2, N,N,N,N-tetramethyl-N,N-butano-1,6-hexanediammonium dibromide, in which two dimethyl-substituted quaternized N-atoms are attached by 1) a (CH.sub.2).sub.6 chain and 2) a (CH.sub.2).sub.4 chain, was confirmed by .sup.13C nmr as there was excellent agreement between observed and calculated nmr line positions.

Example 3: Synthesis of SDA3

N,N,N,N-tetramethyl-N,N-hexano-1,6-hexanediammonium dibromide

(35) ##STR00003##

(36) A 60.00 g portion of 1,6-dibromohexane (96%, Sigma-Aldrich) was placed in a 1-liter beaker and dissolved in 500 ml dry tetrahydrofuran (THF) using a stirbar. The resulting solution was transferred to a 1 liter 3-neck round bottom flask equipped with an overhead stirrer, a heating mantle and a reflux condenser. Separately, 41.09 g N,N,N,N-tetramethyl-1,6-hexanediamine (99%, Sigma-Aldrich) was diluted with 50 ml THF and placed in a pressure-equalizing dropping funnel that was attached to one of the necks of the round bottom flask. The amine solution was then added dropwise to the dibromide solution in the flask, but quickly, with stirring, resulting in a clear solution. Upon completion of the addition, the dropping funnel was removed and a thermocouple connected to a temperature controller was inserted into the flask. The reaction mixture was then heated to 64 C. and held at that temperature for 21 hours. The final reaction mixture consisted of a voluminous white solid suspended in the liquid. The reaction was allowed to cool and the solid product was isolated by filtration under a nitrogen blanket. The solid was washed with ether and filtered under nitrogen blanket before residual solvent was removed using a vacuum oven. The identity of cyclic diquat SDA3, N,N,N,N-tetramethyl-N,N-hexano-1,6-hexanediammonium dibromide, in which two dimethyl-substituted quaternized N-atoms are attached to each other by 1) a (CH.sub.2).sub.6 chain and 2) another (CH.sub.2).sub.6 chain, was confirmed by .sup.13C nmr as there was excellent agreement between observed and calculated nmr line positions.

Example 4

(37) A Teflon beaker was charged with 130.00 g tetrapropylammonium hydroxide (TPAOH, 40%, SACHEM, Inc.) and placed under a high speed overhead stirrer. Then pre-ground aluminum isopropoxide (Sigma-Aldrich, 13.2% Al), 5.23 g was added and dissolved with stirring. Then 17.54 g H.sub.3PO.sub.4 (85.7%) was added dropwise to the reaction mixture with continued stirring, yielding a clear solution. Separately, 5.61 g Zn(OAc).sub.2*2H.sub.2O (Sigma-Aldrich) was dissolved in 25.00 g deionized water. This solution was added fast dropwise to the reaction mixture with stirring, forming a clear solution within five minutes. The reaction mixture was diluted further with 15.00 g deionized water. Separately, 5.58 g of the cyclic diquat SDA1 from Example 1 was dissolved in 33.00 g deionized water. This was added dropwise to the reaction mixture, which induced solid formation immediately and formed a white suspension by the end of the addition. Separately, KOAc (Sigma-Aldrich, 99.4%), 1.26 g, was dissolved in 10.00 g deionized water. This solution was added dropwise to the white gel/suspension. After further homogenization, the reaction mixture was distributed among seven Teflon-lined autoclaves, which were digested quiescently at 95, 125, 150, and 175 C. for either 66 or 189 hours or both at autogenous pressure. The solid products were isolated by centrifugation, washed with deionized water and dried at room temperature. All of the reactions yielded MeAPO-81 products with the BPH topology as determined by powder x-ray diffraction. Representative x-ray diffraction lines observed for the 175 C./189 hours product are given in Table 1. Scanning Electron Microscopic (SEM) analysis of this product showed the crystals to consist of thin rounded hexagonal plates, 0.2 to 0.8 across and less than about 100 nm thick. Elemental analysis on this same product yielded the stoichiometry N.sub.0.31K.sub.0.24Zn.sub.0.51Al.sub.0.51P.

(38) TABLE-US-00003 TABLE 1 2- d() I/I.sub.0 % 6.70 13.18 s 7.56 11.69 vs 10.08 8.77 w 13.12 6.74 m 13.40 6.60 m 14.74 6.00 w 15.07 5.88 w 15.40 5.75 m 16.55 5.35 w 18.82 4.71 m 20.22 4.39 s 21.18 4.19 s 23.82 3.73 m 24.14 3.68 vs 26.54 3.36 m 27.26 3.27 m 27.46 3.24 w 28.30 3.15 m 28.62 3.12 m 29.70 3.01 m 30.16 2.96 m 30.56 2.92 m 33.36 2.68 m 33.90 2.64 m 35.12 2.55 m 36.58 2.45 w 38.12 2.36 w 38.88 2.31 w 40.02 2.25 w 40.86 2.21 w 43.02 2.10 m

Example 5

(39) A Teflon beaker was charged with 130.00 g tetrapropylammonium hydroxide (TPAOH, 40%, SACHEM Inc.) and placed under a high speed overhead stirrer. Then pre-ground aluminum isopropoxide (Sigma-Aldrich, 13.2% Al), 5.23 g was added and dissolved with stirring. Then 17.54 g H.sub.3PO.sub.4 (85.7%) was added dropwise to the reaction mixture with continued stirring, yielding a clear solution. Separately, 5.61 g Zn(OAc).sub.2*2H.sub.2O (Sigma-Aldrich) was dissolved in 25.00 g deionized water. This solution was added fast dropwise to the reaction mixture with stirring, forming a clear solution within five minutes. The reaction mixture was diluted further with 15.00 g deionized water. Separately, 4.96 g of the cyclic diquat SDA2 from Example 2 was dissolved in 33.00 g deionized water. This was added dropwise to the reaction mixture, which induced solid formation immediately and formed a white suspension by the end of the reaction. Separately, KOAc (Sigma-Aldrich, 99.4%), 1.26 g, was dissolved in 10.00 g deionized water. This solution was added dropwise to the white gel/suspension. The reaction mixture was distributed among seven Teflon-lined autoclaves, which were digested quiescently at 95, 125, 150, and 175 C. for either 66 or 188 hours at autogenous pressure. The solid products were isolated by centrifugation, washed with deionized water and dried at room temperature. Powder x-ray diffraction showed all products contained MeAPO-81 with the BPH topology as the major product and several of the products were pure MeAPO-81. Representative x-ray diffraction lines are presented for the pure MeAPO-81 product isolated from the 150 C./66 hours digestion in Table 2 below. Elemental analysis performed on this same sample yielded the stoichiometry N.sub.xK.sub.0.22Zn.sub.0.52Al.sub.0.47P.

(40) TABLE-US-00004 TABLE 2 2- d() I/I.sub.0 % 6.76 13.07 m 7.64 11.57 vs 10.08 8.76 w 13.17 6.71 m 14.82 5.97 w 15.42 5.74 m 16.63 5.33 w 18.88 4.70 w 20.16 4.40 m 21.22 4.18 s 23.86 3.73 m 24.24 3.67 s 26.58 3.35 m 27.34 3.26 m 27.54 3.24 m 28.46 3.13 w 29.76 3.00 m 30.26 2.95 m 30.64 2.92 m 30.74 2.91 m 33.45 2.68 m 34.02 2.63 m 35.21 2.55 w

Example 6

(41) A 3 liter beaker was charged with 1000.00 g TPAOH (40%) and placed under a high speed overhead stirrer. Pre-ground aluminum isopropoxide (13.2% Al), 40.21 g, was added and dissolved with stirring. The reaction mixture was then diluted with 600.00 g deionized water. Then 134.97 g H.sub.3PO.sub.4 (85.7%) was added in a single slow pour with stirring, followed by the addition of 50.00 g deionized water. Separately, 43.18 g Zn(OAc).sub.2*2H.sub.2O was dissolved in 173.84 g deionized water. This solution was added to the reaction mixture in a dropwise fashion intermittently with vigorous stirring. With continued homogenization, a clear solution results. The final solution weight was 2012.1 g.

(42) A 180.00 g portion of this TPA.sup.+-ZnAlP solution was placed in a Teflon beaker positioned under a high speed overhead stirrer. Separately, 0.86 g KOAc (99.4%) and 7.33 g SDA3 from Example 3 were dissolved in 45.00 g deionized water. This solution was added to the reaction mixture dropwise, inducing solid formation with the first few drops. By the end of the addition the reaction mixture was an opaque white gel suspension. The reaction mixture was distributed among seven Teflon-lined autoclaves, which were digested quiescently at 95, 125, 150, and 175 C. for either 52 or 167 hours at autogenous pressure. The solid products were isolated by centrifugation, washed with deionized water and dried at room temperature. Powder x-ray diffraction showed all products contained MeAPO-81 with the BPH topology as the major product and all of the products synthesized at 150 and 175 C. were pure MeAPO-81. Representative x-ray diffraction lines are given in Table 3 below for the product resulting from the 175 C./52 hours digestion. Elemental analysis showed this same material to have the stoichiometry N.sub.0.32K.sub.0.26Zn.sub.0.58Al.sub.0.45P.

(43) TABLE-US-00005 TABLE 3 2- d() I/I.sub.0 % 6.70 13.18 s 7.54 11.72 vs 10.06 8.78 w 13.06 6.77 w 13.39 6.61 w 14.71 6.02 w 15.40 5.75 m 16.51 5.36 w 18.76 4.73 m 20.00 4.44 m 20.16 4.40 m 21.10 4.21 m 23.72 3.75 w 24.1 3.69 s 26.47 3.36 m 27.14 3.28 w 27.38 3.26 w 28.20 3.16 w 28.54 3.13 m 29.60 3.02 m 30.09 2.97 m 30.44 2.93 m 33.22 2.69 m 33.82 2.65 m 34.98 2.56 w 35.67 2.51 w 36.46 2.46 w 37.97 2.37 w 39.66 2.27 w 40.64 2.22 w 42.84 2.11 w 43.36 2.09 w 49.40 1.84 w 50.15 1.82 w