Hierarchically porous zeolites

1. A process for preparing a hierarchically porous zeolite having at least the following characteristics:

Si/Al atomic ratio greater than 1.4 and less than 6,

micropore volume Vμp, in cm 3 ·g −1 , which satisfies the equation Vμp=Vμp R ±15%, where Vμp R represents the micropore volume, in cm 3 ·g −1 , measured under the same conditions, for a zeolite of the same chemical nature and of the same crystalline structure, but the mesoporous outer surface area of which is less than 40 m 2 ·g −1 , and

mesoporosity such that the mesoporous outer surface area is between 40 m 2 ·g −1 and 400 m 2 ·g −1 ;

the process comprising at least the following steps:

a) preparing a growth gel for synthesizing a FAU zeolite of Y type, by mixing a source of silica with a source of alumina, at a temperature of between 0° C. and 60° C.,

b) adding to the growth gel of step a) at least one nucleating agent, at a temperature of between 0° C. and 60° C. to obtain a reaction medium,

c) adding to the reaction medium at least one structuring agent,

d) increasing the temperature to cause a crystallization reaction and obtain zeolite crystals,

e) filtering and washing the zeolite crystals obtained, and

f) drying and calcining the zeolite crystals.

2. The process according to claim 1 , wherein the nucleating agent is a nucleating gel.

3. The process according to claim 2 , wherein the amount of nucleating gel added is between 0.1% and 20%, limits inclusive, relative to the weight of the growth gel.

4. The process according to claim 1 , wherein the nucleating agent is a crystal.

5. The process according to claim 4 , wherein the amount crystal added is between 0.1% and 10% by weight relative to the total weight of growth gel.

6. The process according to claim 1 , wherein the source of silica is sodium silicate or colloidal silica and the source of alumina is alumina trihydrate.

7. The process according to claim 1 , wherein the structuring agent is an organosilane.

8. The process according to claim 1 , wherein the structuring agent is selected from the group consisting of [3-(trimethoxysilyl)propyl]octadecyldimethylammonium chloride, [3-(trimethoxysily)propyl]hexadecyldimethylammonium chloride, [3-(trimethoxysilyl)propyl]-dodecyldimethylammonium chloride, [3-(trimethoxysily)propyl]octylammonium chloride, N3-(trimethoxysilyl)propyl]aniline, 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane, N-[3-(trimethoxysilyl)propyl]-N′-(4-vinylbenzyl)ethylenediamine, triethoxy-3-(2-imidazolin-1-yl)propylsilane, 1-[3-(trimethoxysilyl)propyl]urea, N-[3-(trimethoxysilyl)propyl]-ethylenediamine, [3-(diethylamino)propyl]trimethoxysilane, (3-glycidyloxypropyl)trimethoxysilane, 3-(trimethoxysilyl]propylmethacrylate, [2-(cyclohexenyl)ethyl]triethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, (3-aminopropyl)trimethoxysilane, (3-mercaptopropyl)trimethoxysilane, (3-chloropropyl)trimethoxysilane, and also mixtures of two or more thereof in all proportions.

9. The process according to claim 1 , wherein the amount of structuring agent(s) is such that the structuring agent(s)/starting/Al 2 O 3 mole ratio is between 0.005 and 0.20, limits inclusive.

10. A hierarchically porous zeolite having at least the following characteristics:

Si/Al atomic ratio greater than 1.4 and less an 6,

micropore volume Vμp, in cm 3 ·g −1 , which satisfies the equation Vμp=Vμp R ±15%, where Vμp R represents the micropore volume, in cm 3 ·g −1 , measured under the same conditions wherein the micropore volume is measured according to Dubinin and Raduskevitch by applying standard ISO 15901-3 (2007), for a zeolite of the same chemical nature and of the same crystalline structure, but the mesoporous outer surface area of which is less than 40 m 2 ·g −1 , and

mesoporosity such that the mesoporous outer surface area is between 60 m 2 ·g −1 and 150 m 2 ·g −1 .

11. A hierarchically porous zeolite having at least the following characteristics:

Si/Al atomic ratio between 1.5 and 3, limits inclusive,

micropore volume Vμp, in cm 3 ·g −1 , which satisfies the equation Vμp=Vμp R ±15%, where Vμp R represents the micropore volume, in cm 3 ·g −1 , measured under the same conditions wherein the micropore volume is measured according to Dubinin and Raduskevitch by applying standard ISO 15901-3 (2007), for a zeolite of the same chemical nature and of the same crystalline structure, but the mesoporous outer surface area of which is less than 40 m 2 ·g −1 and

mesoporosity such that the mesoporous outer surface area is between 40 and 400 m 2 ·g −1 .

12. A hierarchically porous zeolite having a leas the following characteristics:

Si/Al atomic ratio greater than 1.4 and less than 6,

a micropore volume Vμp which satisfies the equation Vμp=Vμp R ±3%, where Vμp R represents the micropore volume measured, under the same conditions, for a zeolite of the same chemical nature and of the same crystal structure wherein the micropore volume is measured according to Dubinin and Raduskevitch by applying standard ISO 15901-3(2007), which is perfectly crystalline but having a mesopore outer surface area which is less than 40 m 2 ·g −1

mesoporosity such that the mesoporous outer surface area is between 40 m 2 ·g −1 and 400 m 2 ·g −1 .