3,912,853 United States Patent Off Patented Dec. 2, 96.

s i 2 3,012,853 same reactant ratios which produced substantially pure CRYSTALLENE ZEGELATE Zeolite W at the higher temperatures. Reaction tempera Robert M. Milton, Buffale, N.Y., assignor to Union tures as high as 120° C. yielded a mixed product of Carbide Corporation, a corporation of New York Zeolite W and other zeolites. No Draving. Filled Aug. 26, 1957, Sex. No. 686,382 As a specific example of the invention, a 35 CEainas. (CE. 23-3:3) aluminate solution was prepared by mixing 60 grams of , 50 grams of hydrated alumina con This invention relates to a synthetic crystalline metal taining 0.64 mole of Al2O3 per 100 grams, and 50 milli alumino-silicate of the zeolite type, and to methods of liters of water, and heating the mixture until the solids making this silicate. O dissolved. The solution was then cooled to room tem it is an object of this invention to provide a zeolite perature, and added to 495 grams of a potassium silicate that is suitable for use as an ion-exchanger. solution containing 7.8 weight percent of potassium oxide It is another object to provide a crystalline metal and 19.3 Weight percent of silicon dioxide. The result alumino-silicate of the zeolite type that may be employed as a molecular sieve adsorbent for small molecules. 5 ing mixture was stirred until homogeneous. The result To distinguish the subject synthetic zeolite from other ing reaction mixture had the molar composition of: Zeolitic compositions, both natural and synthetic, the 2.96KO: AlO3:4.97SiO:76HO metal alumino-silicate of this invention will be designated hereinafter by the term "zeolite W.” Crystallization was carried out by heating in a sealed Certain adsorbents, including zeolite W, selectively 20 glass jar at 100° C. for 91 hours. The crystalline prod adsorb molecules on the basis of the size and shape of uct which formed had settled to the bottom of the jar the adsorbate molecule and are called molecular sieves. and the liquor was clear. The product was filtered, Molecular sieves have a sorption area available on the washed to a pH of 10.5 and dried. This product had inside of a large number of uniformly sized pores of the molar composition of: molecular dimensions. With such an arrangement, 25 1.02K2O:Al2O3:3.65SiO3:5.1 HO molecules of a certain size and shape enter the pores and are adsorbed, while larger or differently-shaped mol The crystalline product had the X-ray diffraction pat ecules are excluded. Not all adsorbents behave in the tern shown in Table I. This X-ray diffraction pattern manner of molecular sieves. The common adsorbents, is characteristic of zeolite W. charcoal and silica gel, for example, do not exhibit mo 30 lecular sieve action. TABLE Dehydration to effect the loss of the water of hydra X-ray diffraction pattern for zeolite W tion results in a crystal interlaced with channels of mo lecular dimensions that offer very high surface areas for Interplanar Spacing e the adsorption of foreign molecules. Factors influenc 35 Relative (A.) Miller In Bragg Angle intensity ------dices, hill ing occlusion by activated zeolite W crystals are the size 100 IIIo and polarizing power of the interstitial cation, the polariza Observed Calculated bility and polarity of the occluded molecules, the dimensions and shape of the sorbed molecule relative to 20 9,98 10.03 2CO 49 8.8 8.19 2. those of the channels, the duration and severity of de 54 7.08 7.09 220 hydration and desorption, and the presence of foreign 28 5.34 5.36 32. 56 5.0 5.01 400 molecules in the interstitial channels. It will be under 2. 4,46 4.48 420 stood that the refusal characteristics of zeolite W are 35 4.29 4.28 332 20 3.64 3.66 52. quite as important as the adsorptive or positive adsorp 100 3.25 3.25 6. tion characteristics. For example, if water and iso 75 3, 17 3.17 620 71 2.96 2.96 631 propyl alcohol are to be separated, the process is re 53 2.73 2.73 721 markably effective since the iso-propyl alcohol is refused 12 2.66 2.68 642 26 2.55. 2.55 732 while the water is adsorbed. 0 2.8 2.19 842 Zeolite W may be represented by the general formula 12 1.78 1.77 880 expressed in terms of oxides as follows: 15 ... 72 1.72 10, 6, 0 1.0+0.1M, O: AlO3:4.1-0.8SiO2:XH2O Zeolite W has a cubic unit cell, an edge of which is about 20.055 A. wherein M is at least one monovalent or divalent metal, Zeolite W has also been prepared from an aqueous n is the valence of M, and X in the fully hydrated form 55 sodium aluminate-potassium silicate mixture as shown is about 5.1. in the following example. Zeolite W has been prepared by employing aqueous A sodium aluminate solution was prepared by dis potassium aluminate and poiassium silicate mixtures hav Solving 6.6 grams of sodium aluminate containing 40.7 ing compositions within the following ranges expressed weight percent Na2O and 59.3 weight percent Al-O in as mole ratios of the oxides. 60 15 grams of water with 5 grams of sodium hydroxide. This solution was added to 50 grams of potassium silicate KO/SiO, ------a------From 0.6 to 0.9. solution containing 78.4 weight percent KO and 19.36 SiO2/Al2Os ------. From 4 to 7. weight percent SiO2 with stirring until a homogeneous H2O/K20 ------. From 20 to 30. mixture was obtained. The reaction mixture had the Satisfactory results have been obtained by maintaining 65 following molar composition: the reaction temperature between 75°. C. and 100° C. until crystals are formed. However, a reaction temperature 1.13KO:2.83Na2O: AlO3:4.38SiO2:79HO of 100° C. is preferred in that it is easy to maintain, Crystallization was carried out by heating in a sealed and is high enough to promote the 'eaction and to pro 70 glass jar in a steam bath at 100° C. for 87% hours. The duce crystallization in a reasonable period of time. At crystalline product which formed had settled to the bot 50 C., an annopholis product was obtained using the tom of the jar and the liquor was clear. The product 3,012,853 3. 4. was recovered by filtration and washing. Its analysis TABLE I corresponded to the following formula: Cation-exchanged zeolite Wadsorption data

0.91KO:0.21NaO: AlO3:3.58SiO3:5.1HO Cation------Li Na Ca. g Zil S 5 The crystal structure was confirmed as being that of Percent Exchange------. 22.6 69 52 52.9 S9 62.7 zeolite W by X-ray diffraction examination. Pres Although it is not known to what extent one could Adsorbate Tenn., Sure, Weight percent adsorbate taken up employ sodium in place of potassium in the reactant a C. mixture, the above example shows that at least 72 mole Eig percent substitution can be done. 25 24 16.9 20.5 7.6 9.0 16.9 - 6. G For satisfactory use as an adsorbent, zeolite W must 25 700 3.5 4.7 3.5 6.8 2, 9 5.5 25 700 0.8 2. 2 0.5 O. A. . be at least partially dehydrated (activated). Such activa r-96 OO 1.4 2.3 2, 6 0.9 2.6 2. tion can be carried out by heating the Zeolite to an m-96 140 2.0 1.4 3, 9 0.7 3.. 6 3. -96 40 2.0 2.3 3.5 5 3.5 3.9 elevated temperature under atmospheric pressure, by 25 700 ------.5 10, O 11.6 maintaining the zeolite at room temperature under vacu 25 700 ------5.3 8, 7 5.0 um, or by heating the zeolite to an elevated temperature under reduced pressure. Occasionally the cation exchange will cause a slight Zeolite W which had been activated by heating at 250 change in the X-ray diffraction pattern, but the original C. at slightly reduced pressure had the adsorption data 20 crystal structure remains substantially unchanged. shown in Table II. What is claimed is: 1. A method for preparing a potassium zeolite having TABLE I a composition expressed in terms of oxides as follows: Zeolite W adsorption data 25 1.0-0.1 KO:Al2O3:4.1+0.8SiO2:XHO wherein X in the fully hydrated form is about 5.1, and Adsorption Adsorption Weight having atoms arranged in a unit cell in such a manner Adsorbate Tempera- Pressure, Percent that the X-ray powder diffraction pattern of the Zeolite ture, C. mm. Hg Adsorbed is essentially the same as that shown in Table I, which 30 comprises preparing a potassium-aluminate-silicate water 25 0.03 3.4 25 0.01 5.8 mixture whose composition, expressed in terms of oxides HO------25 O,085 6 mole ratios is: 25 4.5 4.4 253 29 2.7g? K2O/SiO2------. From 0.6 to 0.9, NH------} 225 6.0 3.5 35 SiO2/Al2O3------From 4 to 7. 25 292 0.5 H2O/K:O------. From 20 to 30. 25 4. i. COa------25 90 3.3 maintaining the temperature within the range from about 25 OO 5.7 75° C. to about 100° C. until crystals as previously de 25 0.06 2.0 25 0.70 3.5 fined are formed; and separating the resulting potassium S02------25 12 A.3 40 25 98 4.9 alumino-silicate crystals from the mother liquor. 25 696 5.3 2. A method for preparing a potassium zeolite having 25 0.088 1. a composition expressed in terms of oxides as follows: CH3OH------525 3. 5.2O. 5.2> 1.0.0.1KO:AlO3:4.1-0.8SiO2:XHO 25 30.0 5, 6 25 O 8. 45 wherein X in the fully hydrated form is about 5.1, and 25 0 1, 5 having atoms arranged in a unit cell in Such a manner H2S------25 98 2.7 25 98 3.5 that the X-ray powder diffraction pattern of the zeolite O 25 40 4.0 is essentially, the same as that shown in Table I, which 2------w ------196 130 2.7 comprises preparing a potassium-aluminate-silicate wa 50 ter mixture whose composition, expressed in terms of oxide mole ratios is: Nitrogen at -196° C., n-pentane at 25 C. and car bon monoxide at -78 C. were not substantially ad K2O/SiO2------From 0.6 to 0.9. sorbed by zeolite W. SiO2/Al2O3------From 4 to 7. Thus it may be seen that zeolite W may be employed H2O/K2O------From 20 to 30. to effect the separation of mixtures such as nitrogen and 55 maintaining the temperature within the range from about at -196° C. by selectively adsorbing one com 75 C. to 120° C. until crystals as previously defined are ponent of the mixture, e.g., oxygen, and excluding the formed; and separating the crystals from the mother other, e.g. nitrogen. Other fluid mixtures may be simi liquor. larly separated. 60 3. A method for preparing a potassium zeolite having Another use for zeolite W may be found in the puri a composition expressed in terms of oxides as follows: fication of sulfide-contaminated petroleum hy 1.0-0.1 KO: AlOs:4.1-0.8SiO:XHO drocarbons. Hydrogen sulfide is adsorbed by zeolite W whereas the petroleum hydrocarbons are refused. wherein X in the fully hydrated form is about 5.1, and 65. having atoms arranged in a unit cell in such a manner Potassium zeolite W can be cation-exchanged with that the X-ray powder diffraction pattern of the zeolite monovalent and divalent cations such as lithium, sodium, is essentially the same as that shown in Table I, which calcium, manganese, magnesium, zinc and strontium ions. comprises preparing a potassium-aluminate-silicate water on exchange can be effected by treating the zeolite mixture whose composition, expressed in terms of oxide with a salt solution of the exchanging solution. There mole ratios is: is no need for activation of the zeolite prior to ion-ex 70 change treatment. The adsorption properties of some K2O/SiO2------From 0.6 to 0.9. of the ion-exchanged forms after activation under re SiO2/Al2O3------From 4 to 7. duced pressure at temperatures of at least 150° C. are H2O/KO------From 20 to 30. shown in Table III, 75 maintaining the temperature and about 100 C. until crys 3,012,853 5 6 tals as previously defined are formed; and separating the water mixture whose composition, expressed in terms crystals from the mother liquor. of oxide mole ratios is: 4. A synthetic, crystalline zeolite wherein the composi tion expressed in terms of oxides is substantially as foll NaO- KO lows: SiO, equal to about 0.9 SiO, AlO3 equal to about 4.4 wherein M is at least one metal having a valence up to about 2, n is the valience of the metal and X in the fully 0. H2O hydrated form is about 5.1; and wherein the atoms are Na2O -- KO equal to about 20 arranged in a unit cell in such a manner that the X-ray powder diffraction pattern of said zeolite is essentially KO the same as that shown in Table . equal to about 0.29 5. A synthetic, crystalline zeolite wherein the com NaO-KO position expressed in terms of oxides is substantially as 5 maintaining the temperature at about 100° C. and crys follows: tals as previously defined are formed; and separating the crystals from the mother liquor. 1.0.0. IMO: AlO3:4, 10.8SiO:XH2O 9. A method for preparing a potassium-sodium zeolite having a composition expressed in terms of oxides as wherein M is at least one metal selected from the group 20 follows: consisting of lithium, sodium, potassium, calcium, man ganese, magnesium, zinc and strontium, n is the valence of the metal and X in the fully hydrated form is about wherein M is a mixture of potassium and sodium cations 5.1; and wherein the atoms are arranged in a unit cell and X in the fully hydrated form is about 5.1, and hav in Such a manner that the X-ray powder diffraction pat 25 ing atoms arranged in a unit cell in such a manner that tern of said zeolite is essentially the same as that shown the X-ray powder diffraction pattern of the zeolite is es in Table . sentially the same as that shown in Table I, which com 6. A synthetic, crystalline zeolite wherein the com prises preparing a sodium-aluminate-potassium-silicate position expressed in terms of oxides is substantially as water mixture whose composition, expressed in terms of follows: 30 oxide mole ratios is: Na2O -- KO from about 0.6 to 0.9 wherein X in the fully hydrated form is about 5.1; and SiO, wherein the atoms are arranged in a unit cell in such a 35 manner that the X-ray powder diffraction pattern of said AlOSiO, from about- 4 to 7 zeolite is essentially the same as that shown in Table I. 7. A method for preparing a potassium-sodium zeolite having a composition expressed in terms of oxides as fol HO from about 20 to 30 Iows: Na2O -- KO 40 KO wherein X in the fully hydrated form is about 5.1, and NaO -- KO not less than about 0.28 having atoms arranged in a unit cell in such a manner maintaining the temperature at from about 75° C. to 100 that the X-ray powder diffraction pattern of the zeolite C. until crystals as previously described are formed; and is essentially the same as that shown in Table I, which 45 separating the crystals from the mother liquor. comprises preparing a sodium aluminate-potassium sili 10. A dehydrated synthetic crystalline zeolite having cate water mixture whose composition, expressed in a composition expressed in terms of oxides substantially terms of oxide mole ratios is: as follows: NaO -- KO SiO, equal to about 0.9 50 1.00.--0.1M2O:Al:03:4.1+0.8SiO2 wherein M is at least one metal having a valence up to SiO, equal to about 4.4 about 2, n is the valence of the metal, and wherein the Al2O3 atoms are arranged in a unit cell in such a manner that 55 the X-ray powder diffraction pattern of said zeolite is HO essentially the same as that shown in Table I. NaO--KO equal to about 20 11. A dehydrated synthetic crystalline zeolite in ac cordance with claim 10 wherein the metal is potassium. KO 12. A dehydrated synthetic crystalline zeolite having Na2O -- KO equal to about 0.29 60 a composition expressed in terms of oxides substantially maintaining the temperature within the range from about as follows: 75 C. to 100° C. until crystals as previously defined are formed; and separating the crystals from the mother 0.91KO:0.21NaO: AlO4:3.58SiO, liquor. wherein the atoms are arranged in a unit cell in such a 65 manner that the X-ray powder diffraction pattern of said 8. A method for preparing a potassium-sodium zeolite zeolite is essentially the same as that shown in Table I. having a composition expressed in terms of oxides as 13. A synthetic crystalline zeolite having a composi follows: tion expressed in terms of oxides substantially as follows: 70 0.91KO:0.21NaO: AlO:3.58SiO:XHO wherein X in the fully hydrated form is about 5.1, and wherein X in the fully hydrated form is about 5.1, and having atoms arranged in a unit cell in such a manner wherein the atoms are arranged in a unit cell in such a that the X-ray powder diffraction pattern of the zeolite manner that the X-ray powder diffraction pattern of is essentially the same as that shown in Table I, which said zeolite is essentially the same as that shown in comprises preparing a sodium aluminate-potassium silicate 75 Table I. . . . . 3,012,853 7 8 14. A method as described in claim 1 wherein the FOREIGN PATENTS separated crystals are further heated to produced the de hydrated form of said zeolite. 174,097 Germany ------Jan. 12, 1905 15. A method as described in claim 3 wherein the 451,733 Great Britain ------Aug. 11, 1936 separated crystals are further heated to produce the de OTHER REFERENCES hydrated form of said zeolite. Barrer et al.: "J. Chem. Soc.," Part 3, 2882-2891 16. A method as described in claim 9 wherein the (1956). separated crystals are further heated to produce the de Barrer et al.: “J. Chem. Soc.," 1267-1278 (1951). hydrated form of said zeolite. Barrer et al.: Ibid., 1561-1571 (1952). O Mellor: Comprehensive Treatise on Inorganic and References Cited in the file of this patent Theoretical Chemistry, vol. 6, pages 567-568, Longmans, UNITED STATES PATENTS Green and Co., N.Y., 1925. 2,413,134 Barrer ------Dec. 24, 1946

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