GB1574840A - Zeolites and process for preparing same - Google Patents

Description

(54) ZEOLITES AND PROCESS FOR PREPARING SAME (71) We, UNION CARBIDE CORPORATION, a corporation organized and existing under the laws of the State of New York, United States of America, whose registered office is, 270 Park Avenue, New York, State of New York 10017, United States of America, (assignee of ROBERT WILLIAM GROSE and EDITH MARIE FLANIGEN), do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates in general to zeolitic molecular sieves having relatively high SiO2/Al203 molar ratios, and to a method for preparing same.

The crystalline zeolites, both naturally-occurring and synthetically prepared, are hydrated aluminosilicates whose structures are based on a theoretically limitless threedimensional network of AlOx and SiOy tetrahedra linked by the sharing of oxygen atoms.

Zeolites are commonly represented by the empirical formula M2/nO . At703 x SiO7 . y H20 wherein x is equal to or greater than 2, and n is the valence of the cation M. In the naturally-occurring, i.e., mineral zeolites, the cation is a metal of group I or group II, especially sodium, potassium, calcium, magnesium and strontium. In synthetic species the cation in the as-synthesized form can be, in addition, ammonium and any of a variety of organic nitrogenous cations such as alkylammonium and arylammonium, although the use of some organic nitrogenous compounds such as tetramethylammonium salts have the drawbacks of potential toxicity and relatively high reactant costs. As a general proposition the zeolite cations are at least partly exchangeable, although cation size and steric considerations of the crystal lattice sometimes preclude ion-exchange with or for certain cations, including the above-mentioned organic nitrogenous cations.

For reasons not fully understood, the zeolite species which crystallize from aluminosilicate gels are strongly dependent upon the cation species present therein. For example, gel compositions which produce zeolite A and zeolite X when sodium is the sole alkali metal present, produce zeolite F and zeolite P respectively when potassium is substituted for the sodium in the gel compositions. In other instances, changing the cation species in gel compositions will produce a zeolite of the same crystal configuration but also create changes in the expected Si02/A1201 molar ratio of the zeolite product.

According to the present invention there is provided a synthetic crystalline zeolitic molecular sieve having a chemical composition expressed in terms of moles of oxides of 0.9-3.0 M20 : A1203 : 10-100 SiO2 ; 0-40 H20 n wherein M represents a metallic cation and n represents the valence of M, and having an X-ray powder diffraction pattern having at least the d-spacings set forth in Table I, said zeolitic molecular sieve after being calcined in air at a temperature of 600"C. having an infrared spectrum exhibiting substantially no absorption within the range of 3600-3100 cm' wavenumbers.

In conjunction with the aforesaid chemical composition, the zeolites of this invention possess a distinguishing crystalline structure characterized by an X-ray powder diffraction pattern having at least the following interplanar spacings: TABLE I Interplanar Spacing, d (A) 11.1 + 0.2 10.1 + 0.2 3.85 + 0.07 3.74 + 0.05 3.72 + 0.05 These values were determined by standard techniques. The radiation was the K-alpha doublet of copper, and a scintillation-counter spectrometer with a strip-chart pen recorder was used. The peak heights and the peak or line positions as a function of two times theta (0), where theta is the Bragg angle, were read from the spectrometer chart. From these, the relative intensities and d ( obs. ), the interplanar spacing in A, corresponding to the recorded lines, were determined. In Tables II, III and IV the relative intensities are given in terms of numerical values.

According to the present invention there is also provided a process for preparing a molecular sieve of the present invention wherein M represents sodium and, optionally, another metal selected from Groups I and II of the Periodic System of Elements, which comprises forming an aqueous reaction mixture comprising inorganic reagents and having the following composition in terms of mole ratios of oxides: SiO2/Al2O3 - - - 30 to 90 Na7O/siO2 - - - 0.08 to 0.20 H2O/(Na2O+M2o) - - 80 to 500 n (Na2O+M2O)/SiO2 - - 0.08 to less than 0.25 n wherein M represents a metal cation selected from Groups I and II of the Periodic System of Elements and n represents the valence of M, and maintaining said reaction mixture for a period of from 40 to 200 hours at a temperature of from 80"C. to 210 C. at autogenous pressure.

These zeolites may be exchanged with ammonium or other cations, including metal ions, hydrogen ions, rare earth ions and mixtures thereof by contacting the zeolite with solutions containing the desired cation)s).

Ion-exchange of the original cations by other cation species does not substantially alter the X-ray pattern of the zeolite, but some minor shifts in interplanar spacing and variation in relative intensity can occur. Other minor variations can occur depending on the silicon-to-aluminum ratio of the particular sample and whether or not the sample had been subjected to elevated temperatures. In any event the d-spacings of the X-ray pattern will be within the tolerances indicated in Table I.

In conjunction with the aforesaid chemical composition and X-ray powder diffraction pattern the zeolites according to this invention exhibit certain distinguishing infrared absorption characteristics. Infrared analytical techniques are recognized as highly useful in the study of crystalline zeolites; see for example U.S. Patents 3,506,400 and 3,591,488 to Eberly, Jr. et al., issued april 14, 1970 and July 6, 1971, respectively, and E.M. Flanigen, H.

Khatami and H.A. Szymanski. "Adv. Chem. Series". Vol. 101, 1971 (pg. 201 et seq.) Infrared analysis was employed to characterize the siliceous zeolites prepared according to the process of the present invention involving an organic-free reaction system with the result that such zeolites are in fact clearly distinguishable from the structurally-related materials designated as the "family" of "ZSM-5" materials such as "ZSM-5", disclosed in U.S. Patent 3.702.886 and "ZSM-8", disclosed in British Specification 1,334,243.

Spectra were obtained an a Perkin-Elmer Model 112 single-beam instrument for the hydroxyl-stretching region 3800-3000 cam~', on a Perkin-Elmer Model 621 double-beam instrument for both the mid-infrared region 1600-1300 cam~' and the framework region 1300-300 cam~'. After calcination at 6000c. in air, the samples were run as self-supported wafers (20 mg.). and the spectra in the hydroxyl-stretching region were obtained after thermal treatments at 200"C. in vacuum for two hours.

Referring now to spectra presented in Figure 1 of the accompanying drawings, namely spectra "A" for ZSM-5 and "B" for ZSM-8, it is evident that in the spectral region assigned to hydroxyl-stretching, approximately 3800-3000 cam~1, and particularly in the region 3600-3100 cm~1, there exist in the case of ZSM-5 and ZSM-8 materials broad characteristic absorption bands, i.e. regions of increased optical density values, specifically those centred at about 3450 cm , corresponding to the characteristic frequencies of the O-H bond. In the case of the zeolite material of the present invention, spectrum "C", however, it is also evident from examination thereof that in the region 3600-3100 cm~1 the aforementioned broad absorption bands are now substantially absent in such spectrum.

The mid-infrared region infrared spectra of the three materials ZSM-5, ZSM-8 and the material of the present invention were all run as self-supported wafers in their assynthesized form prior to calcination. Referring now to Figure 2 which shows the C-H deformation region portion (1300-1500 cm~1) of these spectra as "A", "B" and "C" respectively, it is evident from "A" and "B" that the ZSM-5 and ZSM-8 materials exhibit sharp absorption bands, specifically in two groups between 1350-1400 cm~1 and between 1450-1500 cm~1 corresponding to characteristic C-H vibrations of organic groups such as CH3 and CH2 contained therein. In the case of the material of the present invention, however, it is evident from spectrum "C" of Figure 2 that the aforementioned sharp C-H absorption bands are totally missing in such spectrum.

Raman spectroscopy is, like infrared, another useful tool for study and characterization of molecules which records their spectra in the same vibrational energy region. A discussion of the technique, its use and its ability to complement infrared techniques is found in Physical Methods in Inorganic Chemistry, R.S. Drago, Reinhold Pub. Co., new York, New York (1965).

In Figure 3, portions of the Raman spectra of ZSM-5 and of the zeolite of the present invention, both run as pressed pellets of the as-synthesized materials prior to calcination, are shown respectively as curves "A" and "C". Many sharp, strong absorption bands are evident in curve "A"; those in the region 2700-3200 cm~1 being characteristic of C-H stretch vibrations. Those between 100-1700 cm~l are less easily assigned but are characteristic of the ZSM-5 material shown. The absence in curve "C" of all these sharp bands, save one near 380 cam~1, strikingly illustrates the different character of the zeolite of the present invention.

Accordingly it is concluded, among other things, that as a result of the preparative method employed, according to the method of the present invention the siliceous zeolite products when calcined at 6000C. in air are characterized by an infrared spectrum showing substantially no absorption within the region 3600-3100 cam~'.

Zeolites in accordance with the present invention may be readily formed, by preparing a reaction mixture, e.g., an organic-free reaction mixture, having a composition, in terms of mole ratios of oxides, falling within one of the following ranges: I II SiO2/Al2O3 30 to 90 40 to 60 NalO/SiO; 0.08 to 0.20 0.1 H2O/(Na2O+MO) 80 to 500 200 to 400 n (Na2O+M2O)/SiO2 0.08 to less than 0.25 0.1 n wherein M represents a metal cation selected from Groups I and II of the Periodic system of Elements, and n is the valence of cation M. The metal cation M in the expression Na2O + M, O preferably represents lithium, barium, calcium or strontium. When sodium is the only desired metallic cation "M" therein range II is preferred.

In forming the reaction mixture, the reagent sources of the oxides of the aforesaid empirical compositions are those conventionally used in zeolite synthesis. Representative of such reagents are activated alumina, gamma alumina, alumina trihydrate, sodium aluminate, sodium silicate, silica gels, silicic acid, aqueous colloidal silica sols and solid reactive amorphous silicas. The metal oxides represented by l'I2/n0 are preferably added to the reaction mixture in the form of salts readily soluble in water or in the form of hydroxides. Na2O as the source of sodium cation is advantageously added as sodium hydroxide, sodium aluminate or sodium silicate. No alkylammonium or arylammonium compounds are incorporated in this reaction mixture.

Thereafter, the reaction mixture is maintained for a period of from 40 to 200 hours at a temperature of from 80" C to 210 C at autogenous pressure. The resulting crystalline zeolite is then isolated by filtration, washed with water and dried.

Calcination at temperatures above 200 C in an inert atmosphere such as air or nitrogen, or in a vacuum, dehydrates the zeolite and produces a useful adsorbent and catalyst support. The zeolite has an effective pore diameter of about 6A as determined by adsorption characterization. This pore size permits the separation of mixtures of certain organic compounds, for example, non-quaternary carbon-containing paraffins or olefins are selectively adsorbed from mixtures containing molecules which have a quaternary carbon atom. the zeolite is also useful in the separation of p-xylene from mixtures with o-xylene, m-xylene and ethylbenzene.

In one embodiment of the present invention there is provided a process for removing organic molecules from admixture with water molecules, which comprises contacting said mixture with a zeolitic molecular sieve according to the present invention; whereby the organic molecules are selectively adsorbed on said molecular sieve. The water may, for example, be in the liquid or vapour phase.

One separation process contemplated here comprises in general terms the steps of contacting an aqueous solution or mixture such as a wastewater effluent containing an organic compound with the siliceous zeolite of the invention, adsorbing at least a portion of the organic compound in the inner adsorption surfaces of this zeolite and thereafter recovering, optionally as an effluent stream, the treated aqueous solution or mixture exhibiting a depleted organic compound content.

The following examples serve to illustrate the method of preparation and the adsorptive properties of the zeolites of the present invention. The zeolites prepared in each of the examples exhibit, after calcination at 6000C, substantially no infrared absorption within the range of 3600 to 3100 cm-l wavenumbers.

Example I A reaction mixture was prepared by disssolving 1.2g of NaOH and 0.6 g NaAlO2 (30.2 wt.-% Na2O, 44.1 wt.-% Al2O3, 24.3 wt.%-H2O) in 25 g of hot H2O and adding with stirring to 44 g of aqueous colloidal silica sol (30 wt.-% SiO2) in 100 g of H2O. The overall molar oxide composition was: 6.5 Na2O . Al2O3 80 SiO2 3196 H2O.

The reactant mixture was placed in a polytetrafluoroethylene-lined autoclave and maintained at about 200"C and autogenous pressure for about 72 hours. The solid-product was separated by filtration, washed with H2O and dried at 1100C. Chemical analysis of a sample of this product gave the following composition: 1.9 wt.-% Na2O, 2.7 wt.-% Awl203, 89.2 wt.-% SiO2, 5.5 wt.-% H2O. The molar composition was, in terms of oxides, 1.19 Na,O . Al2O3 . 57.2 SiO, . 11.8 H2O.

A portion of the product was activated at 3500C in vacuum for about 16 hours in a McBain-Baker gravemetric adsorption system. The activated zeolite adsorbed 8.2 wt.-% 2 at 750 torr, - 183"C; 3.9 wt.-% isobutane at 750 torr, 23"C; 0.3 wt.-% neopentane at 750 torr, 23 C; and 7.7 wt.-% H2O at 20 torr, 23 C. The X-ray powder diffraction pattern of the zeolite product is set forth in Table II, below: TABLE II d-A I 11.2 15 10.16 24 9.82 4 9.02 4 7.44 1 7.02 1 6.66 1 6.37 2 5.98 4 5.72 3 5.57 2 5.37 1 5.10 1 5.01 3 4.60 1 4.51 1 4.37 4 4.08 1 4.00 4 3.85 41 3.82 27 3.74 15 3.72 10 3.65 5 3.60 1 3.45 6 3.25 2 3.19 2 3.15 1 3.06 3 3.00 4 2.95 1 Example 2 A reaction mixture was prepared by adding 6.4 g of aqueous positive sol (26 wt.-% SiO2, 4 wt.-% Al2O3) to 35 g of aqueous colloidal silica sol (30 wt.-% SiO2) in 64 g of H2O with stirring. To the resultant precipitate was added 1.3 g of NaOH dissolved in 25 g of H2O and 0.6 gram LiOH . H2O dissolved in 25 grams H2O. The overall molar oxide composition was: 3.8 Li2O 6.5 Na2O A1203 . 81.1 SiO2 . 3196 H2O.

The reactant mixture was placed in a polytetrafluouroethylene-lined autoclave and maintained at about 200 C and autogenous pressure for about 70 hours. The solid product was separated by filtration washed with H2O, and dried at 1100C. Chemical analysis of the zeolite product gave the following composition: 1.2 wt.-% Li2O, 1.1 wt.-% Na2O, 2.0 wt.-% Al2q. 91.7 wt.-% SiO2, 3.3 wt.-% H2O. The molar oxide composition was: 2,00 Li2O . 0.90 Na2O . Al2O3 76.4 SiO2 . 9.2 H2O.

A portion of the product was activated at 3500C in vacuum for about 16 hours in a McBain-Baker gravimetric adsorption system. The activated sample adsorbed 7.2 wt.-% O2 at 750 tort, -183 C; 4.1 wt.-% n-butane at 750 torr, 23 C; 9.7 wt.-% SF6 at 750 tort, 23 C; 0.3 wt.-% neopentane at 750 tort, 23 C; and 7.3 wt.-% H2O at 20 tort, 23 C.

Another part of the zeolite product was ion-exchanged by slurrying three times in ~ 10% NaCl solution at about 80 C. The sodium-exchanged sample was filtered, washed with H2O and dried at 110 C. Chemical analysis gave the following composition: 0.5 wt.-% Li2O, 1.4 wt.-% Na2O, 2.1 wt.-% Al2O3, 89.1 wt.-% SiO2, 6.9 wt.-% H2O. The molar oxide composition was: 0.81 Li2O 1.05 Na2O . Al203 . 70.7 SiO2 . 18.2 H2O.

The Na± exchanged sample was then activated at 3500C in vacuum for about 16 hours.

The activated material adsorbed 7.5 wt.-% O, at 750 tort, -182 C; 4.0 wt.-% n-butane at 750 tort, 23 C; 10.4 wt.-% SF, at 750 tort, 23 C; and 8.8 wt.-% H,O at 18 tort, 23 C. The X-ray powder diffraction pattern of this activated zeolite product is set forth in Table III below.

TABLE III d-A I 11.2 13 10.00 85 9.02 1 7.44 1 7.08 1 6.76 1 6.37 1 5.98 4 5.68 3 5.57 2 5.37 1 5.01 9 4.96 10 4.62 1 4.08 3 4.00 4 3.85 38 3.83 23 3.75 12 3.72 10 3.65 8 3.60 9 3.49 3 3.44 4 3.25 2 3.19 1 3.05 3 2.99 4 Example 3 A reaction mixture was prepared by adding 6.4 grams aqueous positive sol (26 wt.-% SiO2, 4 wt.-% Al2O3) to 20 g of aqueous colloidal silica sol (30 wt.-% SiO2) in 74 g of H2O with stirring. 1.3 g of NaOH dissolved in 25 g of H70 and 3.0 g of Ba(OH)2 8 H2O dissolved in 25 g of H70 were then added consecutively with stirring to the silica-alumina precipitate. The molar oxide composition of the resultant mixture was: 3.8 BaO . 6.5 Na2O Al2O3 . 51.1 SiO2 3196 H2O The reactant mixture was placed in a polytetrafluoroethylene- lined autoclave and maintained at about 200 C and autogenous pressure for about 68 hours. The solid product was separated by filtration, washed with H2O and dried at llO"C. Chemical analysis of the zeolite product gave the following composition: 7.4 wt.-% BaO, 2.2 wt.-% Na2O, 3.8 wt.-% Al2O3, 77.2 wt.-% SiO2, 6.5 wt.-% H2O.

The molar oxide composition was: 1.30 BaO . 0.95 Na2O Al2Oq . 34.8 SiO2 9.8 H2O.

A portion of the product was activated at 350 C in vacuum for about 16 hours in a McBain-Baker gravimetric adsorption system. The activated zeolite adsorbed 12.9 wt.-% O2 at 750 torr, -183 C; 7.0 wt.-% n-butane at 750 torr, 23"C; 19.0 wt.-% SF6 at 750 torr, 23"C, and 10.7 wt.-% H70 at 18 torr, 23"C. The X-ray powder diffraction pattern is set forth in Table IV below.

TABLE IV I 11.2 21 10.05 40 9.02 2 7.44 1 7.08 1 6.76 2 6.37 2 5.98 6 5.72 4 5.57 3 5.37 1 5.01 5 4.98 4 4.67 1 4.60 1 4.33 2 4.08 8 3.85 46 3.82 26 3.74 16 3.72 12 3.65 6 3.59 2 3.53 4 3.44 4 3.25 3 3.13 5 3.08 5 3.05 5 3.00 5 Example 4 A reaction mixture was prepared by dissolving 0.6 g of NaOH and 0.6 of NaAlO2 (30.2 wt.-% Na2O, 44.1 wt.-% Al203, 24.3 wt.-% H2O) in 25 g of hot H2O and adding with stirring to 16.5 g of aqueous colloidal silica sol (30 wt.-% of SiO2) in 55 g of H2). The overall molar oxide composition was: 3.8 Na,O . Al20, . 30 SiO2 . 1855 H20.

The reactant mixture was placed in a polytetrafluoroethylene-lined autoclave and maintained at about 200"C and autogeneous pressure for about 120 hours. The solid product was separated by filtration, washed with H2O, and dried at 1100C. The X-ray powder diffraction pattern of the zeolite product contained all of the lines of Table I.

A reaction mixture was prepared by dissolving 0.95 g of NaOH and 0.6 g of NaAlO2 (30.2 wt-% Na2O, 44.1 wt.-% Al70X, 24.3 wt.-% H2O) in 25 g of hot H2O and adding with stirring to 33 g of silica sol (30 wt.-% SiO2) in 33 g of H2O. The overall molar oxide composition was: 5.4 Na2O Al2OX 60 SiO2 1645 H2O.

The reactant mixture was placed in a polytetrafluoroethylene-lined autoclave and maintained at about 200"C. and autogenous pressure for about 70 hours. The solid product was separated by filtration, washed with water and dried at 1100C. The X-ray powder diffraction pattern of the zeolite product contained the lines of Table I.

Example 6 A reaction mixture was prepared by dissolving 1.2 g of NaOH and 0.6 g. of NaAlO2 (30.2 wt-% Na2O 44.1 wt-% Al9O3. 24.3 wt-% H2O) in 25 g. of hot water and adding with stirring to 44 g. of silica sof (30 wt-% SiO2) in 100 g. of water. The overall molar oxide composition was: 6.5 Na2O . AlOX 80 SiO2 3196 H,O The reactant mixture was placed in a polytetrafluoroethylene-lined autoclave and maintained at about 1500C. for about 122 hours. The solid product was separated by filtration, washed with water and dried at llO"C. The X-ray powder diffraction pattern of the zeolite product contained the lines of Table I.

As illustration of the remarkable selectivity of the zeolites according to the present invention for organic materials over water, data are presented in Table V. The procedure employed is as follows: A 1.0 gram sample of the zeolite and 10.0 grams of the aqueous organic solution are placed in a serum bottle which is capped, shaken and allowed to equilibrate for at least 12 hours. A blank (same aqueous organic solution without adsorbent) is always used for comparison. Analysis of the treated solution is done by gas chromatography. The molar SiO2/Al203 ratio of the zeolite was 44.

TABLE V Organic Original Conc. Percent Organic Component of Organic Cmpd. Component Removed 1-butanol 1.0 vol. -% 98 Methylcellosolve* 1.0 vol.-% 67 methanol 1.0 vol.-% 17-27 phenol 0.1 vol-% 70-75 * "Cellusolve" is a Trade Mark Using the same zeolite and the same experimental procedure as that employed to obtain the data of Table V, it was found that 41 per cent of an original concentration of sulfur dioxide in water of 0.7 volume-% was selectively adsorbed by the zeolite.

The foregoing information on the separation capabilities of the zeolites of this invention demonstrates that a variety of useful industrial processes employing this hydrophobic/ organophilic adsorbent are now made possible. As examples of organic components often found in various industrial or municipal waste streams, methanol, butanol, methylcellosolve, phenol and sulfur dioxide are effectively separated from aqueous solutions or admixtures containing such components.

WHAT WE CLAIM IS: 1. A synthetic crystalline zeolitic molecular sieve having a chemical composition expressed in terms of moles of oxides of 0.9-3.0 M2O : Al,Oi : 10-100 SiO2 ; 0-40 H2O n wherein M represents a metallic cation and n represents the valence of M, and having an X-ray powder diffraction pattern having at least the d-spacings set forth in Table I, said zeolitic molecular sieve after being calcined in air at a temperature of 600"C. having an infrared spectrum exhibiting substantially no absorption within the range of 3600-3100 cm~ wavenumbers.

2. A molecular sieve as claimed in claim 1 wherein M represents sodium cations.

3. A molecular sieve as claimed in claim 1 wherein M represents a mixture comprising sodium and lithium cations.

4. A molecular sieve as claimed in claim 1 wherein M represents a mixture comprising sodium and barium cations.

5. A process for preparing a molecular sieve as claimed in any one of claims 1 to 4, wherein M represents sodium and, optionally, another metal selected from Groups I and II of the Periodic System of Elements, which comprises forming an aqueous reaction mixture comprising inorganic reagents and having the following composition in terms of mole ratios of oxides: SiO2/Al2O3 - - - 30 to 90 Na.O/SiO; - - - 0.08 to 0.20 H2O/(Na2O+M2O) - - 80 to 500 (Na2O+M2O)lsio2 - - 0.08 to less than 0.25 n wherein M represents a metal cation selected from Groups I and II of the Periodic system of Elements and n represents the valence of M, and maintaining said reaction mixture for a period of from 40 to 200 hours at a temperature of from 80" C. to 210 C. at autogenous pressure.

6. A process as claimed in claim 4 wherein the reaction mixture has the following composition in terms of mole ratios of oxides:

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (16)

**WARNING** start of CLMS field may overlap end of DESC **. As illustration of the remarkable selectivity of the zeolites according to the present invention for organic materials over water, data are presented in Table V. The procedure employed is as follows: A 1.0 gram sample of the zeolite and 10.0 grams of the aqueous organic solution are placed in a serum bottle which is capped, shaken and allowed to equilibrate for at least 12 hours. A blank (same aqueous organic solution without adsorbent) is always used for comparison. Analysis of the treated solution is done by gas chromatography. The molar SiO2/Al203 ratio of the zeolite was 44. TABLE V Organic Original Conc. Percent Organic Component of Organic Cmpd. Component Removed 1-butanol 1.0 vol. -% 98 Methylcellosolve* 1.0 vol.-% 67 methanol 1.0 vol.-% 17-27 phenol 0.1 vol-% 70-75 * "Cellusolve" is a Trade Mark Using the same zeolite and the same experimental procedure as that employed to obtain the data of Table V, it was found that 41 per cent of an original concentration of sulfur dioxide in water of 0.7 volume-% was selectively adsorbed by the zeolite. The foregoing information on the separation capabilities of the zeolites of this invention demonstrates that a variety of useful industrial processes employing this hydrophobic/ organophilic adsorbent are now made possible. As examples of organic components often found in various industrial or municipal waste streams, methanol, butanol, methylcellosolve, phenol and sulfur dioxide are effectively separated from aqueous solutions or admixtures containing such components. WHAT WE CLAIM IS:

1. A synthetic crystalline zeolitic molecular sieve having a chemical composition expressed in terms of moles of oxides of 0.9-3.0 M2O : Al,Oi : 10-100 SiO2 ; 0-40 H2O n wherein M represents a metallic cation and n represents the valence of M, and having an X-ray powder diffraction pattern having at least the d-spacings set forth in Table I, said zeolitic molecular sieve after being calcined in air at a temperature of 600"C. having an infrared spectrum exhibiting substantially no absorption within the range of 3600-3100 cm~ wavenumbers.

2. A molecular sieve as claimed in claim 1 wherein M represents sodium cations.

3. A molecular sieve as claimed in claim 1 wherein M represents a mixture comprising sodium and lithium cations.

4. A molecular sieve as claimed in claim 1 wherein M represents a mixture comprising sodium and barium cations.

5. A process for preparing a molecular sieve as claimed in any one of claims 1 to 4, wherein M represents sodium and, optionally, another metal selected from Groups I and II of the Periodic System of Elements, which comprises forming an aqueous reaction mixture comprising inorganic reagents and having the following composition in terms of mole ratios of oxides: SiO2/Al2O3 - - - 30 to 90 Na.O/SiO; - - - 0.08 to 0.20 H2O/(Na2O+M2O) - - 80 to 500 (Na2O+M2O)lsio2 - - 0.08 to less than 0.25 n wherein M represents a metal cation selected from Groups I and II of the Periodic system of Elements and n represents the valence of M, and maintaining said reaction mixture for a period of from 40 to 200 hours at a temperature of from 80" C. to 210 C. at autogenous pressure.

6. A process as claimed in claim 4 wherein the reaction mixture has the following composition in terms of mole ratios of oxides:

SiO2/Al203 - - - 40 to -60 Na2O/SiO2 O. 1 0.1 H2O/(Na2O+M2O - - - 200 to 400 n (Na2O +M2O)/SiO2 - - 0.1 n

7. A process as claimed in claim 5 or claim 6 wherein sodium is the sole cation represented by M.

8. A process as claimed in claim 5 or claim 6 wherein M in the expression Na20 + M2/nO represents lithium cations.

9. A process as claimed in claim 5 or claim 6 wherein M in the expression Na2O + MVnO represents barium cations.

10. A process for removing organic molcules from admixture with water molecules which comprises contacting said mixture with a zeolitic molecular sieve as claimed in any one of claims 1 to 4 whereby the organic molcules are selectively adsorbed on said molecular sieve.

11. A process as claimed in claim 10 wherein the water is in the liquid phase.

12. A process as claimed in claim 10 wherein the water is in the vapor phase.

13. A process for removing sulfur dioxide from admixture with water which comprises contacting said mixture with a zeolitic molecular sieve as claimed in any one of claims 1 to 4, whereby at least a portion of the sulfur dioxide is selectively adsorbed on said molecular sieve.

14. A zeolitic molecular sieve as claimed in claim 1 and substantially as hereinbefore described with reference to any one of the Examples.

15. A process as claimed in claim 5 and substantially as hereinbefore described with reference to any one of the Examples.

16. A process as claimed in claim 10 and substantially as hereinbefore described with reference to any one of the Examples.