Solid-acid catalyzed paraffin alkylation with rare earth-modified molecular sieve adsorbents

Abstract

This invention describes methods of alkylating isobutane which include a catalytic reaction system comprising a crystalline zeolite catalyst and a rare earth-modified molecular sieve adsorbent (RE-MSA). The crystalline zeolite catalyst comprises sodalite cages and supercages, a Si/Al molar ratio of 20 or less, less than 0.5 weight percent alkali metals; and up to 5 wt % of Pt, Pd and or Ni, and acid-site density (including both Lewis and Brnsted acid sites) of at least 100 mole/gm. The RE-modified molecular sieve adsorbent (Re-MSA) comprising sodalite cages and supercages, a Si/Al molar ratio of 20 or less, less than 1 wt % of alkali metals, RE (rare earth elements) in the range of 10 to 30 wt % and transition metals selected from groups 9-11 in the range from 2 wt % to 10 wt; and acid-site density of no more than 30 mole/gm. The invention also includes methods of making RE-MSA.

Claims

1. A method of alkylating isobutane, comprising: passing a feed mixture consisting of excess isobutane and C2 to C5 olefins into a reaction chamber; wherein the reaction chamber comprises a catalyst system comprising: a crystalline zeolite catalyst comprising sodalite cages and supercages, a Si/Al molar ratio of 20 or less, less than 0.5 weight percent alkali metals; and up to 5 wt % of Pt, Pd and or Ni, and acid-site density (including both Lewis and Brnsted acid sites) of at least 100 mole/gm; and a RE-modified molecular sieve adsorbent (Re-MSA) comprising sodalite cages and supercages, a Si/Al molar ratio of 20 or less, less than 1 wt % of alkali metals, RE (rare earth elements) in the range of 10 to 30 wt % and transition metals selected from groups 9-11 in the range from 2 wt % to 10 wt; and acid-site density of no more than 30 mole/gm.

2. The method of claim 1 wherein, at steady state, at least 90% of the C2-C5 olefins are converted to products comprising C8 isomers, and wherein the Research Octane Number (RON) of the products remains above 90; and conducting the process for a catalyst age of 2.5 or greater over the same catalyst system without regeneration; and wherein steady state means that the selectivity to C.sub.8 isomers changes by 10% or less over the entire period that the catalyst age is determined.

3. The method of claim 1 wherein the crystalline zeolite catalyst comprises rare earth elements in the range of 10 to 35 wt %; and wherein the Re-MSA comprises a micro-pore diameter of at least 8 Angstroms, or in the range of 8 to 12 .

4. The method of claim 1 wherein the concentration of C2 to C5 olefins in the feed is between 1 wt % and 30 wt %.

5. The method of claim 1 wherein at an entrance of a catalyst bed comprising the catalyst system, the ratio of the concentration of iso-butane to the concentration of C2-C5 olefins is between 100-1000 mol/mol.

6. The method of claim 1 wherein crystalline zeolite the catalyst and Re-MSA are regenerated in a flowing gas stream that is essentially hydrogen at a temperature of at least 250 C.; and wherein the crystalline zeolite catalyst comprises 0.1 wt % to 5 wt %, or 0.5 to 4 wt %, or 1.0 to 3.0 wt %, of an element selected from the group consisting of Pt, Pd, Ni, and combinations thereof.

7. The method of claim 1 wherein the reaction chamber comprises a packed crystalline zeolite catalyst bed followed by a Re-MSA bed.

8. The method of claim 1 wherein the reaction chamber comprises alternating beds of crystalline zeolite catalyst and Re-MSA comprising at least 2 crystalline zeolite catalyst beds and 2 Re-MSA beds.

9. The method of claim 1 wherein the reaction chamber comprises a packed bed consisting of a mixture of crystalline zeolite catalyst and Re-MSA.

10. The method of claim 1 conducted at a pressure of 250 to 400 psig.

11. The method of claim 1 wherein the olefin space velocity is between 0.05/hr to 0.5/hr.

12. The method of claim 1 wherein the crystalline zeolite catalyst and Re-MSA are regenerated with a flow of gas which is at least 50 volume % hydrogen.

13. The method of claim 1 wherein the catalyst and Re-MSA is regenerated in flowing hydrogen at a temperature of at least 250 C. and a GHSV of at least 500 hr.sup.1.

14. The method of claim 1 wherein the method is run continuously for a catalyst age of 2-3.5 without regenerating the crystalline zeolite catalyst or Re-MSA.

15. The method of claim 1 wherein the reaction chamber comprises a packed Re-MSA bed followed by a crystalline zeolite catalyst bed.

16. The method of claim 1 wherein a ratio of the Re-MSA weight to crystalline zeolite catalyst weight in the reaction chamber is between 0.1 to 10 wt/wt.

17. The method of claim 1 wherein the reaction chamber comprises a packed bed of particles, comprising crystalline zeolite catalyst and Re-MSA wherein at least 95 wt % of the particles have particle diameters of at least 0.1 mm.

18. The method of claim 1 conducted at a temperature between 45 and 90 C.

19. The method of claim 1 wherein the C.sub.2 to C.sub.5 olefin contains less than 100 ppm water.

20. The method of claim 1 comprising conducting the process for a catalyst age of 2.5 or a catalyst age of 3.0.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1 schematically illustrates the test unit used for screening adsorbents.

GLOSSARY

(2) Catalyst AgeCatalyst age is the mass of olefin fed to the reactor divided by the mass of catalyst+ mass of adsorbent.

(3) Catalyst LifetimeThe catalyst age at which the olefin conversion falls below 90% is defined as the catalyst lifetime.

(4) Calcination TemperatureThe term calcination temperature refers to the maximum temperature utilized as an intermediate step in the catalyst synthesis procedure intended to remove the hydration sphere from lanthanum ions and allow solid-state exchange between lanthanum and sodium cations in the sodalite and supercages

(5) Regeneration TemperatureThe solid acid catalyst may be regenerated under flowing hydrogen gas at elevated temperatures in order to hydrocrack heavier hydrocarbons and remove them from the zeolitic structure. The maximum temperature used in this step is referred to as the regeneration temperature.

(6) ConversionThe term conversion of a reactant refers to the reactant mole or mass change between a material flowing into a reactor and a material flowing out of the reactor divided by the moles or mass of reactant in the material flowing into the reactor. For example, if 100 grams of olefin are fed to a reactor and 10 grams of olefin exit the reactor, the conversion is [(100-10)/=100]90% conversion of olefin.

(7) A crystalline zeotype material means the material can be detected by x-ray diffraction and that it possesses a three dimensional silica framework with open channels into the material. The materials are also called zeolite structures. A description of a large number of zeolite structures can be found in the Zeomics structural compendium through the website http://helios.princeton.edu/zeomics/; although measurements of channel openings in specific catalysts should be determined by conventional techniques. Although typical zeolites are aluminosilicates, aluminum is not necessary in the catalysts used in the present invention that preferably contain less than 1 wt % Al, preferably <0.5 or <0.1 or <0.01 wt % Al; unless otherwise specified, these compositions refer to the catalyst including binder or, in some preferred embodiments refer to the composition within the crystalline phase. The crystalline zeotype catalyst used for converting methane and/or DME to olefins can be referred to as Si/Ti zeotype catalyst indicating Ti in the zeolite SiO framework.

(8) RON stands for Research octane number and is a well-known measure of fuel quality.

(9) OlefinsAs used herein, the term olefin has its ordinary meaning in the art, and is used to refer to any unsaturated hydrocarbon containing one or more pairs of carbon atoms linked by a double bond. The term light olefins refers to C.sub.2-C.sub.6 olefins. In this invention, C.sub.2-C.sub.6 olefins refers to ethylene, propylene, n-butylenes, isobutylene, and the various isomers of pentene and hexene. The phrase C.sub.2-C.sub.6 olefins has the standard meaning encompassing any combination of olefins in the C.sub.2 to C6 range, with no minimum requirement for any of the C2 to C6 compounds.

(10) One of ordinary skill in the art will understand how to determine the pore size (e.g., minimum pore size, average of minimum pore sizes) in a catalyst. For example, x-ray diffraction (XRD) can be used to determine atomic coordinates. XRD techniques for the determination of pore size are described, for example, in Pecharsky, V. K. et at, Fundamentals of Powder Diffraction and Structural Characterization of Materials, Springer Science+Business Media, Inc., New York, 2005. Other techniques that may be useful in determining pore sizes (e.g., zeolite pore sizes) include, for example, helium pycnometry or low-pressure argon adsorption techniques. These and other techniques are described in Magee, J. S. et at, Fluid Catalytic Cracking: Science and Technology, Elsevier Publishing Company, Jul. 1, 1993, pp. 185-195. Pore sizes of mesoporous catalysts may be determined using, for example, nitrogen adsorption techniques, as described in Gregg, S. J. at al, Adsorption, Surface Area and Porosity, 2nd Ed., Academic Press Inc., New York, 1982 and Rouquerol, F. et al, Adsorption by powders and porous materials. Principles, Methodology and Applications, Academic Press Inc., New York,

(11) As is conventional, the phrase having a molecular dimension of 5.1-5.6 (or the like) refers to the largest channel openings within the MFI structure (not the largest cavity sizes) which limit the size of compounds that can escape the interior of the zeolite. This may also be known as the pore limiting diameter. The presence of the MFI structure can be characterized by x-ray diffraction (XRD), N.sub.2 adsorption-desorption isotherms. An example is presented by Silvestre-Albero et al., Desilication of TS-1 zeolite for the oxidation of bulky molecules, Cat. Comm. 44 (2014) 35-39. As is conventionally understood, the phrase tetrahedral titania does not require the titania to be exactly tetrahedral, but that it meets the characteristic values for Ti-substituted zeolites such as those mentioned in conjunction with the paper by Silvestre-Albero et al. As is conventionally known, the stated molecular dimensions within the crystalline structure can be determined by known techniques, particularly the conventional gas adsorption/desorption technique such as that described in the paper by Silvestre-Albero et al. The techniques for determining pore structure should converge to the same values; however, if there is a significant discrepancy, the gas adsorption/desorption technique described in the paper by Silvestre-Albero et al. will be determinative.

(12) SelectivityThe term selectivity refers to the amount of production of a particular product (or products) as a percent of all products resulting from a reaction. For example, if 100 grams of products are produced in a reaction and 80 grams of octane are found in these products, the selectivity to octane amongst all products is 80/100=80%. Selectivity can be calculated on a mass basis, as in the aforementioned example, or it can be calculated on a molar basis, where the selectivity is calculated by dividing the moles a particular product by the moles of all products. Unless specified otherwise, selectivity is on a mass basis.

(13) YieldThe term yield is used herein to refer to the amount of a product flowing out of a reactor divided by the amount of reactant flowing into the reactor, usually expressed as a percentage or fraction. Mass yield is the mass of a particular product divided by the weight of feed used to prepare that product.

(14) When unspecified, % refers to mass % which is synonymous with weight %. Ideal gas behavior is assumed so that mole % is the same as volume % in the gas phase.

(15) As is standard patent terminology, the term comprising means including and does not exclude additional components. Any of the inventive aspects described in conjunction with the term comprising also include narrower embodiments in which the term comprising is replaced by the narrower terms consisting essentially of or consisting of. As used in this specification, the terms includes or including should not be read as limiting the invention but, rather, listing exemplary components. As is standard terminology, systems include to apparatus and materials (such as reactants and products) and conditions within the apparatus.

(16) The invention is further elucidated in the examples below. In some preferred embodiments, the invention may be further characterized by any selected descriptions from the examples, for example, within 20% (or within 10%) of any of the values in any of the examples, tables or figures; however, the scope of the present invention, in its broader aspects, is not intended to be limited by these examples.

Example 1

(17) The starting material was a commercial 13 X molecular sieve from Sigma Aldrich having a SiO2/Al2O3 molar ratio of 2.8 (Si/Al of 1.4) and a sodium content of 15% by weight. This adsorbent is designated as Adsorbent A.

Example 2

(18) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular in 150 mL of 0.2 M Lanthanum nitrate solution and heated to 80 C. while stirring for 2 hours. The lanthanum solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 450 C. for 4 hours. This adsorbent is designated as Adsorbent B.

Example 3

(19) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve in 150 mL of 0.2 M nickel nitrate solution and heated to 80 C. while stirring for 2 hours. The solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 450 C. for 4 hours. This adsorbent is designated as Adsorbent C.

Example 4

(20) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve was suspended in 150 mL of 0.2 M copper nitrate solution and heated to 80 C. while stirring for 2 hours. The nitrate solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 450 C. for 4 hours. This adsorbent is designated as Adsorbent D.

Example 5

(21) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve was suspended in 150 mL of 0.2 M barium nitrate solution and heated to 80 C. while stirring for 2 hours. The nitrate solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 450 C. for 4 hours.

(22) The ion-exchanged molecular sieve was suspended in a 0.5 M ammonium nitrate solution and heated to 80 C. with stirring for 2 hours. The ammonium solution was decanted and replaced with fresh solution. This ion exchange was performed 3 times followed by 2 water washes of 75 mL each. The ion-exchanged molecular sieve was then dried and calcined at 450 C. for 4 hours. This adsorbent is designated as Adsorbent E.

Example 6

(23) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve was suspended in 150 mL of 0.2 M calcium nitrate solution and heated to 80 C. while stirring for 2 hours. The nitrate solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 450 C. for 4 hours.

(24) The ion-exchanged molecular sieve was suspended in a 0.5 M ammonium nitrate solution and heated to 80 C. with stirring for 2 hours. The ammonium solution was decanted and replaced with fresh solution. This ion exchange was performed 3 times followed by 2 water washes of 75 mL each. The ion-exchanged molecular sieve was then dried and calcined at 450 C. for 4 hours. This adsorbent is designated as Adsorbent F.

Example 7

(25) Alkylation activity experiments were performed using an isothermal packed bed reactor setup shown in FIG. 1 such that the d.sub.T/d.sub.p>10 and the L/d.sub.p>50. Heating was controlled using an Omega temperature control unit and a ceramic heating element. Feeds were sent through a preheater of 75 cm length prior to entering the reactor.

(26) ExSact-3000 catalyst (15 gm) and adsorbent of interest (10 gm) were first loaded into a reactor and activated by flowing 1 LPM of nitrogen at 350 C. for 4 hours and then cooled to the reaction temperature of 45 C. The reactor was then pressurized with iso-butane to 300 psig. The reaction feed mixture of excess iso-butane and 1-butene was fed to the reactor at a WHSV of 1/hr. The recycle ratio was maintained at 40 vol/vol. Product samples were withdrawn hourly and analyzed using a gas chromatograph equipped with a Petrocol DH 100 m column. The effect of adsorbents on the performance of ExSact 3000 catalyst for alkylation of 1-butene with isobutane is shown in Table 1.

(27) TABLE-US-00001 TABLE 1 Performance of adsorbents using 13X molecular sieve Starting 1.sup.st 2.sup.nd Catalyst Adsorbent # Material Exchange Exchange Lifetime None Base A 13 X none none 0 B 13 X La.sup.+3 none 1.23 Base C 13 X Ni.sup.+2 none Base D 13 X Cu.sup.+2 none Base E 13 X Ba.sup.+2 NH.sup.4+ 0.8 Base F 13 X Ca.sup.+2 NH.sup.4+ 0.8 Base
Table 1 shows the benefits of using a RE-exchanged molecular sieve as an adsorbent

Example 8

(28) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve was suspended in 150 mL of 0.8 M lanthanum nitrate solution and heated to 80 C. while stirring for 2 hours. The nitrate solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 600 C. for 4 hours.

(29) The ion-exchanged molecular sieve was suspended in a 0.2 M barium nitrate solution and heated to 80 C. with stirring for 2 hours. The nitrate solution was decanted and replaced with fresh solution. This ion exchange was performed 3 times followed by 2 water washes of 75 mL each. The ion-exchanged molecular sieve was then dried and calcined at 450 C. for 4 hours. This adsorbent is designated as Adsorbent G.

Example 9

(30) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve was suspended in 150 mL of 0.8 M lanthanum nitrate solution and heated to 80 C. while stirring for 2 hours. The nitrate solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 600 C. for 4 hours.

(31) The ion-exchanged molecular sieve was suspended in a 0.2 M lithium nitrate solution and heated to 80 C. with stirring for 2 hours. The nitrate solution was decanted and replaced with fresh solution. This ion exchange was performed 3 times followed by 2 water washes of 75 mL each. The ion-exchanged molecular sieve was then dried and calcined at 450 C. for 4 hours. This adsorbent is designated as Adsorbent H.

Example 10

(32) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve was suspended in 150 mL of 0.8 M lanthanum nitrate solution and heated to 80 C. while stirring for 2 hours. The nitrate solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 600 C. for 4 hours.

(33) The ion-exchanged molecular sieve was suspended in a 0.2 M calcium nitrate solution and heated to 80 C. with stirring for 2 hours. The nitrate solution was decanted and replaced with fresh solution. This ion exchange was performed 3 times followed by 2 water washes of 75 mL each. The ion-exchanged molecular sieve was then dried and calcined at 450 C. for 4 hours. This adsorbent is designated as Adsorbent I.

Example 11

(34) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve was suspended in 150 mL of 0.2 M lanthanum nitrate solution and heated to 80 C. while stirring for 2 hours. The nitrate solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 450 C. for 4 hours.

(35) The ion-exchanged molecular sieve was suspended in a 0.8 M aluminum nitrate solution and heated to 80 C. with stirring for 2 hours. The nitrate solution was decanted and replaced with fresh solution. This ion exchange was performed 3 times followed by 2 water washes of 75 mL each. The ion-exchanged molecular sieve was then dried and calcined at 600 C. for 4 hours. This adsorbent is designated as Adsorbent J.

Example 12

(36) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve was suspended in 150 mL of 0.8 M lanthanum nitrate solution and heated to 80 C. while stirring for 2 hours. The nitrate solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 600 C. for 4 hours.

(37) The ion-exchanged molecular sieve was suspended in a 0.2 M phosphoric acid solution and heated to 80 C. with stirring for 2 hours. The acid solution was decanted and replaced with fresh solution. This ion exchange was performed 3 times followed by 2 water washes of 75 mL each. The ion-exchanged molecular sieve was then dried and calcined at 450 C. for 4 hours. This adsorbent is designated as Adsorbent K.

Example 13

(38) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve was suspended in 150 mL of 0.8 M lanthanum nitrate solution and heated to 80 C. while stirring for 2 hours. The nitrate solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 600 C. for 4 hours.

(39) The ion-exchanged molecular sieve was suspended in a 0.2 M lanthanum nitrate solution and heated to 80 C. with stirring for 2 hours. The nitrate solution was decanted and replaced with fresh solution. This ion exchange was performed 3 times followed by 2 water washes of 75 mL each. The ion-exchanged molecular sieve was then dried and calcined at 450 C. for 4 hours. This adsorbent is designated as Adsorbent L.

Example 14

(40) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve was suspended in 150 mL of 0.8 M lanthanum nitrate solution and heated to 80 C. while stirring for 2 hours. The nitrate solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 600 C. for 4 hours.

(41) The ion-exchanged molecular sieve was suspended in a 0.2 M boric acid solution and heated to 80 C. with stirring for 2 hours. The acid solution was decanted and replaced with fresh solution. This ion exchange was performed 3 times followed by 2 water washes of 75 mL each. The ion-exchanged molecular sieve was then dried and calcined at 450 C. for 4 hours. This adsorbent is designated as Adsorbent M.

Example 15

(42) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve was suspended in 150 mL of 0.8 M lanthanum nitrate solution and heated to 80 C. while stirring for 2 hours. The nitrate solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 600 C. for 4 hours.

(43) The ion-exchanged molecular sieve was suspended in a 0.2 M nickel nitrate solution and heated to 80 C. with stirring for 2 hours. The nitrate solution was decanted and replaced with fresh solution. This ion exchange was performed 3 times followed by 2 water washes of 75 mL each. The ion-exchanged molecular sieve was then dried and calcined at 450 C. for 4 hours. This adsorbent is designated as Adsorbent N.

Example 16

(44) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve was suspended in 150 mL of 0.8 M lanthanum nitrate solution and heated to 80 C. while stirring for 2 hours. The nitrate solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 600 C. for 4 hours.

(45) The ion-exchanged molecular sieve was suspended in a 0.2 M copper nitrate solution and heated to 80 C. with stirring for 2 hours. The nitrate solution was decanted and replaced with fresh solution. This ion exchange was performed 3 times followed by 2 water washes of 75 mL each. The ion-exchanged molecular sieve was then dried and calcined at 450 C. for 4 hours. This adsorbent is designated as Adsorbent O.

Example 17

(46) The 13X molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve was suspended in 150 mL of 0.8 M lanthanum nitrate solution and heated to 80 C. while stirring for 2 hours. The nitrate solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 600 C. for 4 hours.

(47) The ion-exchanged molecular sieve was suspended in a 0.2 M cobalt nitrate solution and heated to 80 C. with stirring for 2 hours. The nitrate solution was decanted and replaced with fresh solution. This ion exchange was performed 3 times followed by 2 water washes of 75 mL each. The ion-exchanged molecular sieve was then dried and calcined at 450 C. for 4 hours. This adsorbent is designated as Adsorbent P.

Example 18

(48) Alkylation activity experiments were performed as described in Example 7. Results are summarized in table 2.

(49) TABLE-US-00002 TABLE 2 Performance of adsorbents using RE-exchanged 13X molecular sieves Starting 1.sup.st 2.sup.nd Catalyst Adsorbent # Material Exchange Exchange Lifetime G 13 X La.sup.+3 Ba.sup.+ 0 H 13 X La.sup.+3 Li.sup.+ Base I 13 X La.sup.+3 Ca.sup.+2 Base J 13 X La.sup.+3 Al.sup.+3 0.86 Base K 13 X La.sup.+3 PO.sup.4 Base L 13 X La.sup.+3 La.sup.+3 0.76 Base M 13 X La.sup.+3 B.sup.+ 0.54 Base N 13 X La.sup.+3 Ni.sup.+2 1.5 Base O 13 X La.sup.+3 Cu.sup.+2 3 Base P 13 X La.sup.+3 Co+2 4 Base
Table 2 shows benefits of performing a second ion-exchanged with either Cobalt (Group 9), Nickel (Group 10) or Copper (Group 11) when using a RE-exchanged molecular sieve as an adsorbent

Example 19

(50) The starting material was a commercial NaY molecular sieve from Sigma Aldrich having a SiO2/Al2O3 molar ratio of 5.2 and a sodium content of 13% by weight. This adsorbent is designated as Adsorbent Q.

Example 19

(51) The NaY molecular sieve was ion-exchanged by suspending 15 grams of the molecular sieve was suspended in 150 mL of 0.2 M lanthanum nitrate solution and heated to 80 C. while stirring for 2 hours. The nitrate solution was decanted and replaced with a fresh solution. The ion-exchanges were repeated two more times followed by 2 water washes of 75 mL each. The molecular sieve was then left to dry at room temperature. Following the ion-exchange, the molecular sieve was calcined in a muffle furnace at a temperature of 450 C. for 4 hours.

(52) The RE-exchanged NaY molecular sieve was suspended in a 0.2 M copper nitrate solution and heated to 80 C. with stirring for 2 hours. The nitrate solution was decanted and replaced with fresh solution. This ion exchange was performed 3 times followed by 2 water washes of 75 mL each. The ion-exchanged molecular sieve was then dried and calcined at 450 C. for 4 hours. This adsorbent is designated as Adsorbent R.

Example 20

(53) The adsorbent was prepared by adding copper nitrate solution on to the high surface area g-alumina support via incipient wetness technique. The adsorbent was then left to dry at room temperature. Following the impregnation, the adsorbent was dried and calcined in a muffle furnace at a temperature of 450 C. for 4 hours. This adsorbent is designated as Adsorbent S.

Example 21

(54) Alkylation activity experiments were performed as described in Example 7. Results are summarized in table 3.

(55) TABLE-US-00003 TABLE 3 Performance of adsorbents using NaY molecular sieves and g-alumina as starting material Starting 1.sup.st 2.sup.nd Catalyst Adsorbent # Material Exchange Exchange Lifetime Q NaY none none 0 R NaY La.sup.+3 Cu.sup.+2 Base S Al.sub.2O.sub.3 8 wt % Cu none Base

(56) Table 3 shows neither RE-exchanged Y zeolite with Copper nor copper impregnated on g-alumina provides benefits as an adsorbent for paraffin alkylation.

LITERATURE CITED

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