Improved zeolite L

Claim 2

1 A zeolite having an X-ray diffraction pattern obtained from CuKg radiation with the significant d values set out in Table A hereinbefore and comprising crystallites in the form of cylinders characterised in that the cylinders have a mean diameter of greater than 0.5 micron.

Claim 3

2 A zeolite as claimed in claim 1, having at least 50% of its crystallites as cylinders.

Claim 4

3 A zeolite as claimed in claim 2, having at least 70% of its crystallites as cylinders.

Claim 5

4 A zeolite as claimed in any of claims 1 to 3, wherein the cylindrical crystallites have a mean diameter of from 0.5 to 4 micron.

Claim 6

5 A zeolite as claimed in any of claims 1 to 4, wherein the aspect ratio of the cylinders is at least 0.5.

Claim 7

6 A zeolite as claimed in any of claims 1 to 5, wherein the aspect ratio of the cylinders is from 0.5 to 1.5.

Claim 8

7 A zeolite as claimed in any of claims 1 to 6, having a composition expressed in terms of the molar ratio of oxides assuming an anhydrous state of: (0.9-1.3)M 2/n O:Al 2 O 3 :xSiO 2 wherein M is a cation of valence n and x is from 5 to 7.5.

Claim 9

8 A zeolite as claimed in claim 7, wherein x is from 5.7 to 7.4.

Claim 10

9 A zeolite as claimed in claim 8, wherein x is from 6 to 6.5.

Claim 11

10 A zeolite as claimed in any of claims 7 to 9, wherein M is potassium.

Claim 12

11 A zeolite as claimed in any of claims 7 to 10, wherein the mole ratio M 2/n O:Al 2 O 3 is from 0.95 to 1.15.

Claim 13

12 A process for the preparation of a zeolite having an x-ray diffraction pattern obtained from CuK α radiation with the significant d values set out in Table A hereinbefore, in which process an alkaline reaction mixture comprising water, a source of silicon and a source of aluminium is heated characterized in that to form the zeolite with the crystallites in the form of cylinders with a mean diameter of at least 0.1 micron and an aspect ratio of at least 0.5, the reaction mixture has a composition (expressed in the mole ratios of oxides) of: (wherein M is a cation of valence n) and is heated to a temperature of from at least 75°C.

Claim 14

12 A process for the preparation of a zeolite having an x-ray diffraction pattern obtained from CuK α radiation with the significant d values set out in Table A hereinbefore, in which process an alkaline reaction mixture comprising water, a source of silicon and a source of aluminium is heated characterized in that to form the zeolite with the crystallites in the form of cylinders with a mean diameter of at least 0.1 micron and an aspect ratio of at least 0.5, the reaction mixture has a composition (expressed in the mole ratios of oxides) of: (wherein M is a cation of valence n) and is heated to a temperature of from at least 75°C.

Claim 15

13 A process as claimed in claim 12, in which M is potassium (K) or a mixture of K+M' in which M' is an alkali metal other than potassium, provided that the molar ratio K 2/ M' 2 0 + K 2 0 is at least 0.7.

Claim 16

14 A process as claimed in claim 12 or claim 13, in which the reaction mixture is heated to a temperature of at least 100°C.

Claim 17

15 A process as claimed in claim 12, in which the temperature is from 100 to 250°C.

Claim 18

16 A process as claimed in any oc claims 12 to 15, in which the temperature difference with the reaction mixture is not more than 15°C at any time.

Claim 19

17 A process as claimed in any of claims 12 to 16, in which the reaction mixture has the composition:

Claim 20

18 A process as claimed in claim 17, in which the reaction mixture has the molar composition: (2.4-3.0)K 2 0:(0.6-1.25)A1 2 0 3 :(8-12)Si0 2 :(120-240)H 2 0

Claim 21

19 A process as claimed in claim 12, in which the relative proportions of aluminium, water, silicon and potassium in the reaction mixture (measured as wt% of the oxides) are such that the reaction mixture falls within area I A in Figure 1, area I B in Figure 2, area I C in Figure 3 and area I D in Figure 4, and the reaction mixture is heated to from 120 to 225°C.

Claim 22

20 A process as claimed in claim 19, in which the reaction mixture falls within area II A in Figure 1, area II B in Figure 2, area II C in Figure 3 and area II D in Figure 4.

Claim 23

21 A process as claimed in claim 20, in which the reaction mixture falls within area III A in Figure 1, area III B in Figure 2, area III C in Figure 3 and area III D in Figure 4.

Claim 24

22 A process as claimed in any of claims 12 to 21, in which the mole ratio of H 2 O/(M 2/n 0+Al 2 O 3 + Si0 2 ) is greater than 8.

Claim 25

23 A process for the preparation of a zeolite having an x-ray diffraction pattern obtained from CuK α radiation with the significant d values set out in Table A hereinbefore, in which an alkaline reaction mixture comprising water, a source of silicon, a source of aluminium and a source of potassium is heated characterized in that to form the zeolite with crystallites in the form of cylinders with a mean diameter of at least 0.1 micron and an aspect ratio of less than 0.5, the reaction mixture has a composition (expressed in mole ratios of oxides) of: (wherein M is as defined in claim 1) and is heated to a temperature of at least 75°C.

Claim 26

24 A catalyst comprising a zeolite having an x-ray diffraction pattern obtained from CuK t radiation with the significant d values set out in Table A hereinbefore and a catalytically-active metal characterized in that the zeolite comprises crystallites in the form of cylinders with a mean diameter of at least 0.1 micron.

Claim 27

24 A catalyst comprising a zeolite having an x-ray diffraction pattern obtained from CuK t radiation with the significant d values set out in Table A hereinbefore and a catalytically-active metal characterized in that the zeolite comprises crystallites in the form of cylinders with a mean diameter of at least 0.1 micron.

Claim 28

25 A catalyst as claimed in claim 24, in which the catalytically active metal is or includes platinum.

Claim 29

26 A catalyst as claimed in claim 25, comprising 0.4 to 1.2 wt% platinum.

Claim 30

27 A catalyst as claimed in any of claims 24 to 26, in which the zeolite is in the potassium form.

Claim 31

28 The use in an aromatization process in which hydrocarbons are contacted with a catalyst comprising a catalytically active metal on a catalyst base, of a catalyst base comprising a zeolite having an X-ray diffraction pattern obtained from CuK radiation with the significant d values set out in Table A hereinbefore and comprising crystallites in the form of cylinders with a mean diameter of at least 0.1 micron.

Claim 32

28 The use in an aromatization process in which hydrocarbons are contacted with a catalyst comprising a catalytically active metal on a catalyst base, of a catalyst base comprising a zeolite having an X-ray diffraction pattern obtained from CuK radiation with the significant d values set out in Table A hereinbefore and comprising crystallites in the form of cylinders with a mean diameter of at least 0.1 micron.

Claim 33

29 A process for the dehydrocyclization and/or isomerization of hydrocarbons, in which the hydrocarbons are contacted at a temperature of from 430°C to 550°C with a catalyst comprising a zeolite having an X-ray diffraction pattern obtained from CuK k radiation with the significant d values set out in Table A hereinbefore, having at least 90% of the exchangeable cations M as alkali metal ions and incorporating at least one Group VIII metal having dehydrogenating activity, so as to convert at least part of the acyclic hydrocarbons into aromatic hydrocarbons characterized in that the zeolite comprises crystallites in the form of cyclinders with a mean diameter of at least 0.1 micron.

Claim 34

29 A process for the dehydrocyclization and/or isomerization of hydrocarbons, in which the hydrocarbons are contacted at a temperature of from 430°C to 550°C with a catalyst comprising a zeolite having an X-ray diffraction pattern obtained from CuK k radiation with the significant d values set out in Table A hereinbefore, having at least 90% of the exchangeable cations M as alkali metal ions and incorporating at least one Group VIII metal having dehydrogenating activity, so as to convert at least part of the acyclic hydrocarbons into aromatic hydrocarbons characterized in that the zeolite comprises crystallites in the form of cyclinders with a mean diameter of at least 0.1 micron.

Claim 35

30 A process for the conversion of hydrocarbons, in which the hydrocarbons are contacted at an appropriate temperature of from 430°C to 550°C with a catalyst comprising a zeolite having an X-ray diffraction pattern obtained from CuK α radiation with the significant d values set out in Table A hereinbefore chracterized in that the zeolite comprises crystallites in the form of cylinders with a mean diameter of at least 0.1 micron.

Claim 36

30 A process for the conversion of hydrocarbons, in which the hydrocarbons are contacted at an appropriate temperature of from 430°C to 550°C with a catalyst comprising a zeolite having an X-ray diffraction pattern obtained from CuK α radiation with the significant d values set out in Table A hereinbefore chracterized in that the zeolite comprises crystallites in the form of cylinders with a mean diameter of at least 0.1 micron.