Patent EA-001226-B1 (EA)
Title: Process for producing aromatic compounds from aliphatic hydrocarbons
Inventor: CLEM KENNETH R
IPC: B01J29/80
Filed: 1997-05-29
Abstract: 1. A process for the production of aromatic hydrocarbons by the dehydrocyclo-oligomerization of aliphatic hydrocarbons which comprises contacting a feedstream containing aliphatic hydrocarbons under dehydrocyclo-oligomerization conditions with a zeolite bound zeolite catalyst which does not contain significant amounts of non-zeolitic binder and comprises:  (a) first crystals of an intermediate pore size first zeolite having acid activity; and,  (b) a binder comprising second crystals of a second zeolite having less acid activity than the first zeolite. 2. The process recited in claim 1 wherein the second crystals are intergrown and form at least a partial coating on the first crystals. 3. The process recited in claim 1 or 2 wherein the catalyst contains less than 5% by weight of non-zeolitic binder based on the combined weight of first zeolite and second zeolite. 4. The process recited in any preceding claim wherein the first crystals have an average particle size of at least 0.1 micron (0.1 μm) and the second crystals have an average particle size less than that of the first crystals. 5. The process recited in claim 4 wherein the first crystals have an average particle size of from about 1 to about 6 microns (1 to about 6 μm) and the second crystals have an average particle size of from about 0.1 to about 0.5 microns (0.1 to about 0.5 μm). 6. The process recited in any preceding claim wherein the first zeolite and the second zeolite are independently an aluminosilicate zeolite or a gallium silicate zeolite. 7. The process recited in claim 6 wherein the first zeolite is an aluminosilicate zeolite having a silica to alumina mole ratio of from 20:1 to 300:1. 8. The process recited in claim 6 or 7 wherein the second zeolite is an aluminosilicate zeolite having a silica to alumina mole ratio greater than 200:1. 9. The process recited in any preceding claim wherein the second zeolite is an intermediate pore size zeolite. 10. The process recited in any preceding claim wherein the structure type of the first zeolite is selected from the group consisting of AEL, MFI, MEL, MTW, MTT, FER, TON, and EUO. 11. The process recited in claim 10 wherein the first zeolite has an MFI structure. 12. The process recited in any preceding claim wherein the second zeolite has an MFI or MEL structure. 13. The process recited in any preceding claim wherein the structure type of the second zeolite is the same as the first zeolite. 14. The process recited in any preceding claim wherein the second zeolite is silicalite or silicalite 2. 15 The process recited in any preceding claim wherein the first zeolite is SAPO-11. 16. The process recited in any preceding claim wherein the second zeolite is ALPO- 11. 17. The process recited in any preceding claim wherein the catalyst contains at least one metal component selected from the group consisting of Groups IIB-IVB of the Periodic Table of Elements, preferably gallium. 18. The process recited in any preceding claim wherein the catalyst is selectivated. 19. The process recited in claim 18 wherein the catalyst is selectivated with a selectivation agent comprising a silicon compound, preferably hexamethyldisiloxane. 20. The process recited in any preceding claim wherein the catalyst is preparable by aging at elevated temperature a silica-bound aggregate containing the first crystals of first zeolite in an aqueous ionic solution containing hydroxy ions. 21. The process recited in any preceding claim wherein the aliphatic hydrocarbons have from 2 to about 6 carbon atoms. 22. The process recited in claim 21 wherein the aliphatic hydrocarbons comprise isobutane, normal butane, isobutene, normal butene, propane or propylene. 23. The process recited in any preceding claim wherein the dehydrocyclo-oligomerization conditions comprise a temperature of from about 350 degree  to about 650 degree C and/or a pressure of from about 0.1 to about 2.03 MPa (1 to 20 atmospheres) and/or a liquid hourly space velocity of from about 0.2 to about 5 liquid volumes of the aliphatic hydrocarbons per hour per volume of the catalyst composition. 24. The process recited in any preceding claim wherein the product contains greater than equilibrium amounts of para-xylene.