DE1813099A1 - Process for the production of zeolite L. - Google Patents

Description

PATENT ADVOCATE DR. HANS-GUNTHER EGGERT, DIPLOMA CHEMIST

5 KDLN-LINDENTHAL PETER-KINTGEN-STRASSE 2

Cologne, 2 _β 12.1968 Eg / Ax

Union Carbide Corporation, 2 John Park Avenue, "evi York • ^T. Y. Iool7 (U.S.A.)

Process for the production of zeolite L.

The invention relates to a method for producing a three-dimensional crystalline zeolite, in particular a improved process for making zeolite L.

Zeolite L is a synthetic three-dimensional crystalline zeolite of the molecular sieve type which is relatively large pore diameters and the following composition stoichiometrically expressed in molar ratios of the Oayde Has:

0.9-1.3 M ₂ O: Al ₂ O ₃ : 5.2-6.9 SiO ₂ : y H ₂ O

~ Here M is at least one exchangeable cation, η the valence of M and y any number from 0 to about 9

Slight fluctuations in the molar ratios of the oxides within those specified by the formula above Regions do not significantly change the crystal structure or physical properties of the zeolite. as well the value of "y" for all samples of zeolite L is not necessarily an unchangeable quantity. This is because different exchangeable cations produce a different one Size, and because of the exchange of these different Cations no significant change in the crystal lattice dimensions of the zeolite occurs, is more or * \

909833/1203 r

less space available for the uptake of water molecules »The value of" y "therefore depends on the identity the exchangeable cation and also the degree of dehydration of the zeolite.

All one-, two- and trivalent metal ions in question, especially those of groups I, II and III of the Periodic Table, published in Webster's Mew Collegiate Dictionary, 1956, p. 626, e.g., barium, calcium, ger, lithium, Magnesium, potassium, sodium, strontium and zinc ions, as well as other cations, e.g. hydrogen and ammonium ions, which in zeolite L behave like the above-mentioned metal ions in that they are exchangeable by others Cations can be replaced without significantly changing the basic crystal structure of the zeolite to cause. Of the exchangeable cations, monovalent and divalent cations are particularly advantageous because they usually find easier entry into the cavities of the zeolite crystal.

Zeolite L differs from all other zeolite molecular sieves by its characteristic X-ray powder diffraction pattern. Zeolite L has the following X-ray diffraction pattern, expressed in characteristic d-values, i.e. the interplanar distances in αϊ

* 0.3 Table A. 3.17 + 0.01 ± 0.04 d (S) 3.07 + 0.01 16.1 ± 0.04 2.91 + 0.01 7.52 + 0.04 2.65 + 0.01 6.00 + 0.04 2.46 + 0.01 4.57 + 0.02 2.42 + 0.01 4.35 + 0.02 2.19 + 0.01 3.91 + 0.02 3.47 3.28

909833/1203

A more complete characterization of zeolite L and the description of the usual process for its preparation can be found in US Pat. No. 3,216,789. In general, the process described there consists in the digestion and crystallization of an aqueous metal aluminosilicate mixture in which the reactants are present as moles of alkali metal oxide , H ₂ O, Al ₂ O ₅ and SiO ₂ that fall within one of the following ranges:

Table B.

Area a Area b Area c K ₂ O / (K ₂ 0 + Na ₂ O) 0.33 to 1 0.26 to 1 0.33 to 1

(K ₂ 0 + Na ₂ 0) / Si0 ₂ 0.35 to 0.5 0.34 to 0.5 0.4 to 0.5 SiO ₂ Al ₂ O ₃ 10 to 28 15 to 28 15 to 28 H ₂ 0 / (K ₂ 0 + Na ₂ 0) 15 to 41 15 to 51 15 to 41

A consideration of these areas shows that relatively small changes in the proportions of certain reaction participants can have relatively large effects on the permissible proportions of other reaction participants, but the SiO ₂ / Al ₂ O, ratios have in all of them

A minimum value of 10 in areas and a minimum value of 15 in two areas f. Furthermore, in all of these known reaction systems, the molar ratio of H ₂ O to the sum of the other oxidic reactants is a minimum of about 3.6.

According to the invention, it was surprisingly found that zeolite L can be obtained in high yield and good purity if a reaction system is used in which the Si0 ₂ / Al ₂ 0 ₅ ratio is 6.7 to 9 »5, and that at the preferred embodiment contains very small amounts of water. Due to the low SiOg / AlgO ^ ratio, the high cost of the silicon source

909833/1203

serving material lowered, which are associated with corresponding economic advantages, and the low Water content of the reaction mixture allows the use of devices and machines that are suitable for the Handling and conveying of solids are constructed in place of the more cumbersome and complicated Devices and machines for handling and conveying liquids, usually for the production are used by synthetic crystalline zeolites,

As noted, there are a number of cations that can be present in zeolite L, but is preferred the potassium form of the zeolite is synthesized, i.e. the form in which the exchangeable cations present are predominantly Potassium ions and the remainder are sodium ions. The exchangeable cations present in the zeolite can then can be replaced by other exchangeable cations in a simple and known manner, with isomorphic forms of Zeolite L can be obtained.

In the broadest context of the invention, the process consists in that an aqueous potassium-sodium aluminosilioate reaction mixture forms in which the source of at least 80 mol # silicon is a reactive amorphous solid SiIioiumdioxyd is, and one in the molar ratio of Oxides expressed composition within the range

K ₂ O / (K ₂ 0 + Na ₂ O) 0.7 to 1

(K ₂ 0 + Na ₂ O) / SiO ₂ 0.23 to 0.35

SiO ₂ Al ₂ O ₅ 6.7 to 9.5

H ₂ 0 / (K ₂ 0 + Na ₂ 0) 10.5 to 50.

has, and this reaction mixture to a temperature of about 100 to 200 '
are formed.

heated to about 100 to 20O ⁰ C until crystals of zeolite L

909833/1203

T! ¹ ? ''"W. ! ■ pi ' ¹ .ν ¹¹ » ¹ ■'"

$ 181,309

In the reaction periods in the above-mentioned range of molar ratios of the oxides, in which the H ₂ O / (K ₂ O + Na ₂ O + 3iO ₂ + Al _{2 O 3} ) ratio is never about 2 to about 6, the combined reaction participants have a consistency of a somewhat hot powder to a very stiff paste.

Given the complex crystalline structure of Zeolite 1, it was surprising to find that a dry Gel form a suitable medium for crystallization and that the product yields are sufficiently high for the largest part of the procedure to be carried out This embodiment of the method is also used four major problems posed to the Ubliohen Wet gel methods occur, namely the dispersion of solid amorphous silicon dioxide, the grinding of gels in certain proportions, the filtration of the reaction mass after crystallization and the removal of the mother » lye · Another advantage is that the Trookengelverfahren can be carried out continuously In contrast to the Ohargen operation, which is generally used in the Haßgel method

As a reactive amorphous solid silicon dioxide, which is useful for the purposes of the invention as the main source of silicon is used, any materials of this type are suitable, ζ · Β · vapor-phase silicon dioxide, ohemlsoh precipitated Silioiuadioxyde and precipitated silica sol . which preferably have a final particle size of less than about 1µ. These silicon dioxides are everywhere for example under the names "Santooel", "Oab-o-oil", "Hi-SiI" and "QUSO" commercially available. Am Part of the need for silicon up to 20 mol-jt can duroh Reactants, such as amorphous aluminosilicates, materials of the metakaolin type, acid-treated metakaolins,

909833/1203

• intensely ground metakaolins, aqueous colloidal silica sols of the "IiUdox" type, soluble silicates, silica gels and Silicic acid, instead of reactive amorphous solid silicon dioxide are covered *

Aluminum compounds that have heretofore been generally used for the supply of aluminum in reaction systems for the production of zeolite molecular sieves are generally also suitable for the purposes of the invention. γ-aluminum oxide, aluminum hydrate, α-aluminum oxide and

Potassium aluminate as suitable reagents, of which aluminum

oxide Niuny trihydrate is preferably used «

Potassium and sodium are preferably introduced into the reaction mixture in the form of their hydroxides. The silicates and / or aluminates of these metals can also be used.

If the reactants are added to form the reaction systems from which zeolite L crystallizes, the order of misoing is not divinely important. In general, the gels are prepared as follows! First, the potassium hydroxide is in a part of the water to be used dissolved. Aluminum oxide hydrate or another source of aluminum oxide is added to this solution for the formation of potassium aluminate

this mixture can be optionally erhitet to about 90 ⁰ C, "The restliohe water of the selected Silioiumdioxyds is used with the sodium hydroxide to the slurry" The Silioiumdioxydaufsohlämmung is then mixed with the previously formed potassium aluminate solution "for the" Irooken- gel "reaction mixtures, a pan mill or ribbon mixer is used. Suitable for the more fluid systems a paddle mixer or a propeller mixer.

909833/1203

After mixing, the reaction mixture is poured into the Heated reaction kettle, in which the digestion or brewing temperature is during the desired Time is maintained. A movement of reaction «- Mixture during digestion is not necessary. After the digestion-crystallization time has elapsed, the zeolite L formed is separated off. The crystals of zeolite L are dried and / or activated as required for the intended use *

example 1

A high purity zeolite L was prepared using Gribbsite ™ as the aluminum source, reactive solid amorphous silica ("Hi-SiI 233" Pittsburgh Plate Glass Company) as the silicon source, KOH ₁ NaOH and

Water produced. 20 kg of water became 20.7 kg of KOH

· dissolved To this solution was added (65 wt .- ^ Al ₂ O ,, 35 wt .- ^ HgO) 13.49 kg gibbsite, was heated whereupon daa mixture to form potassium aluminate at 9O ⁰ C. 53 kg of silicon dioxide were placed in a separate vessel "Hi-Sil" 233 "slurried in 109.84 kg water with 4.04 kg NaOH · This slurry was mixed with the aluminate solution at ambient temperature using a propeller mixer for 3 hours The mixture had the following in molar proportions of the oxides expressed composition ι

K ₂ 0 / (K ₂ 0 + Na ₂ 0) - 0.8 (K ₂ 0 + Na ₂ 0) / Si0 ₂ << 0.314 SiO ₂ / Al ₂ O ₅ - 8.75

H ₂ O / (K ₂ 0 + Na ₂ O) * 31.8 H ₂ 0 / (K ₂ 0 + Na ₂ 0 + Si0 ₂ + Al ₂ 0 ₃ ) «7.0

This reaction mixture was carried out with a steam jet pump transferred to a 250! pressure vessel which was heated by a steam jacket. The digestion was carried out for 24 hours at

909833/1203

ORIGINAL INSPECTED

8th -

134 ⁰ O carried out without movement. After the reaction time, the jar was cooled and opened. The contaminants were filtered off and washed with water for about 48 hours until the washing water running off had a p n value of 9.5. Samples of the product were analyzed by X-ray diffraction and oxygen adsorption experiments. The product was identified as absolutely pure zeolite I, which according to the oxygen adsorption method had a purity of 94t 6 $ and according to X-ray analysis a purity of 100 $

Example 2

A silica slurry was prepared by flaking 2,260 grams of deionized water, 717 grams of solid amorphous silica, and 55 grams of NaOH. The resulting mixture had a temperature of 26 ⁰ C. A Aluminfctlösung was prepared by mixing 300 g deionized water, 182 g Aluminiumoxydtrlhydrat and 300 g of potassium hydroxide were added together. The mixture was heated to 90 ⁰ C and then cooled to 25 ⁰ O. The two mixtures so prepared were mixed using a propeller mixer. The resulting mixture had a temperature of 30 ⁰ C. The mixture of the reactant had the following composition in mole ratios of the oxides:

K ₉ O

■ - £ - = 0.80

K ₂ O + Na ₂ O

K ₉ O + Na ₉ O
= * 0.314 SiO ₂

SiO ₉

* = 8.75

Al ₂ O ₅

H ₉ O

45.4

K ₂ O + Na ₂ O
909833/1203

■ :! .. ^■■.!; | :: Ι ϊ !!> ⁱ 'if FSIUIiP = τ · vf "ir IWJ>If; !!! TI !! iiiVH il"!...'. ■> ■■■. ■ '■ '·;»i; ^

The digestion and crystallization of the Reaktionsgemisohes were performed 300 hours at 10O ⁰ C in a 4 1 glass vial. Analysis of samples of the solid product by X-ray diffraction and the oxygen adsorption method showed that zeolite L of 10056 purity had been formed. The chemical analysis gave the following molar composition}

K ₂ O - 0.772 Na ₂ O "0.285 Al ₂ O ₃ - 1.00 SiO ₂ - 5.79 H ₂ O - 5.26 Example 3

In the manner described in Example 2, a zeolite L (molar ratio SiO ₂ Al ₂ O ₃ = 5.3) of 100ji purity (according to oxygen adsorption analysis) was prepared from the following reactants!

Silloium oxide insulation Deionized water

20 (solid amorphous silicon dioxide) 76% NaOH in flakes

Alumina solution

Deionized water Al ₂ O ₃ . 3 H ₂ O 25 KOH

The reaction mixture, which consists of grinding the above ingredients in a pan grinder for 30 minutes was obtained had the following composition in molar ratios of the oxide

909833/1203

229.3 G 1721.0 β 111.7 β 615.0 β 5 * 4.4 8th 613.0 G

- ι U ■ "

K ₉ O ^ά 0.80

K ₂ O -I- Na ₂ O

K ₀ O + Na ₉ O
^ά - »0.268

SiO ₂

SiO ₉

S- »7.1

AIgO ₃

H ₉ O ^ά - 10.5

KgO + Na ₂ O

H ₂ O

K ₂ 0 + Na ₂ 0 + Si0

= 2.0

This reaction mixture had the consistency of a moist powder. The AU:
was 300 hours.

th powder. The digestion crystallization time at 100 ^° C

Example 4

A zeolite L that had a purity of 9856 (determined by oxygen adsorption analysis) became from a reactant mixture produced, which had the following total in molar ratios of the oxides

K ₂ O ι 0 K ₂ 0 + Well ₂ 0 ^Κ 2 0 + Well ₂ SiO 2 SiO 2 ^Η 2 0

K ₂ O + Na ₂ O

8.75

18 909833/1203

H ₉ O ² - 4.0

KgO + NagO + AlgOj + SiOg

As Silioiumdioxydquelle the product of the trade name of "Hi-Sil 233" used · The reactant mixture which was a stiff paste 300 hours at 100 ⁰ C. The zeolite L formed was through characteristic X-ray powder diffraction pattern identified.

Example 5

A zeolite L that had a purity of 93 # (determined by oxygen adsorption analysis) was prepared from a reactant mixture having the following Ge total composition in holing proportions of the oxides

0.70

0.314

8.75

K ₂ O +
KgO - Well ₂
Well ₂ 0
0 SiO ₂
SiO ₂ H ₂ O KgO + N / A 2 °

- 36.4

A reactive amorphous solid silica ^N Hi-Sil233 ^{N was} used as the source of silica. The reactant mixture was ^{kept at 140 °} C. for 53 hours. The formed zeolite L was identified from such a characteristic X-ray powder diffraction pattern.

909833/1203

- 12 -

Example 6

A zeolite L (SiO ₂ / Al ₂ Oj molar ratio 6.0) which had a purity of more than 90% (determined by oxygen adsorption analysis) was produced from a reaction participant mixture which contained a reactive amorphous solid silicon dioxide and the following overall composition in molar proportions of the oxides

1.0

0.314

K ₂ 0 κ ₂ ο +
κ ₂ ο + Na ₂ O
Na ₂ O SiO
SiO CJ CVl Al ₂ O
H ₂ O 3

+ Na ₂ O

36.4

The reaction ^{temperature was kept at 140 0} O for 45 hours. The zeolite L formed was identified by its characteristic X-ray powder diffraction pattern.

J5 example 7

Zeolite Ii was made from a reaction mixture which contained a reactive, amorphous solid silica and the following, in molar ratios of the oxides expressed composition had:

K ₂ O
^m 0 _t 80

K ₉ O + Na ₉ O

~ ~ »0.229

SiO ₂

909833/1203

SiO 2 Al ₂ O 3 H ₂ 0

8.43

Na ₂ O

H ₉ O * 3.0

K ₂ O + Na ₂ O + Al ₂ O ₅ + SiO ₂

The reaction ^{temperature of 100 °} C. was maintained for 300 hours. The zeolite L formed was identified by its characteristic X-ray powder diffraction pattern.

909833/1203

Claims (1)

Claims 1) Method of making zeolite L from a Reaction mixture containing the hydroxides of sodium and potassium and aluminum and silicon carriers, characterized in that a reaction mixture is prepared which has a low water content and a the composition, empirically expressed in molar ratios of the oxides, is within the following ranges: K ₂ 0 / (K ₂ 0 + Na ₂ O) = 0.7 to 1
(K ₂ O + Na ₂ 0) / Si0 ₂ = 0.23 to 0.35 SiO ₂ Al ₂ O ₃ = 6.7 to 9.5
H ₂ 0 / (K ₂ 0 + Na ₂ O) = 10.5 to 50 as a source of at least 80 moles-96 of the silicon in A reactive amorphous solid silica is used in this mixture and then the mixture at a temperature of about 100 to 200 ° 0 until crystals of zeolite I have been formed. P 2) Method according to claim 1, characterized in that the molar ratios of the oxides are chosen so that the relationship H ₂ O / (K ₂ O + Na ₂ O + SiO ₂ +
has a value of no more than about 6. 90 9'8 33/1203