Hydrocarbon conversion process with a composite zeolite

Claim 2

A hydrocarbon conversion process comprising contacting, under hydrocarbon conversion conditions, a hydrocarbon feed with a catalyst comprising a crystalline modified-silica zeolite having a constraint index of from 1 to 12 overlying a silica core having substantially the same crystalline structure as the modified-silica zeolite.

Claim 3

Process of claim 1 wherein the silica core is a silica polymorph of analogous structure to the modified-silica zeolite, so that the silica core alone and the complete catalyst display substantially the same x-ray diffraction patterns.

Claim 4

Process of claim 1 wherein the silica core is a silica polymorph having, after calcination in air for at least one hour at 600° C., a mean refractive index of 1.39±0.01 and a specific gravity at 25° C. of 1.70±0.05.

Claim 5

Process of claim 3 wherein the silica core is a silica polymorph having an x-ray powder diffraction pattern in which the six strongest d-values are: 11.1±0.2 Å 10.0±0.2 Å 3.85±0.07 Å 3.82±0.07 Å 3.76±0.05 Å 3.72±0.05 Å

Claim 6

Process of claim 3 wherein the silica polymorph has a pore diameter in the range of from 5 to 6 Angstrom units and a pore volume of 0.18 ml/g, determined by adsorption.

Claim 7

Process of claim 3 wherein the silica polymorph has, following calcination in air for at least an hour at 600° C., an adsorptive capacity for water vapour at 23° C. and a water vapour pressure of 4.6 mm Hg of less than 1 wt.%, an infra-red spectrum which exhibits a substantial absence of absorption in the region of 3700-3100 cm -1 , and an x-ray powder diffraction pattern containing at least the following d-values: 11.1±0.2 10.0±0.2 9.75±0.1 3.85±0.04 3.82±0.04 3.71±0.02 3.62±0.02 and showing an absence of reflections intermediate the reflections corresponding to d-spacings of 3.82±0.04 Å and 3.71±0.02 Å.

Claim 8

Process of claim 1 wherein the silica core is a silicate resulting from thermal treatment at a temperature of from 200° C. to 600° C. for from 1 to 48 hours of a crystal metal organosilicate having a composition, in its anhydrous state, in terms of mole ratios of oxides as follows: 0.9±0.2(xR.sub.2 O+(1-x)M.sub.2/n O):<0.005Al.sub.2 O.sub.3 :>1 where M is sodium or sodium in combination with tin, calcium, nickel or zinc, R is a tetraalkylammonium and x is a number greater than 0 but not exceeding 1, the organosilicate having the following characteristic x-ray diffraction lines: ______________________________________ Interplanar spacing d (Å) Relative Intensity ______________________________________ 11.1±0.2 s 10.0±0.2 s 7.4±0.15 w 7.1±0.15 w 6.3±0.1 w 6.04 ±0.1 w 5.97 5.56±0.1 w 5.01±0.1 w 4.60±0.08 w 4.25±0.08 w 3.85±0.07 vs 3.71±0.05 s 3.04±0.03 w 2.99±0.02 w 2.94±0.02 w ______________________________________

Claim 9

Process of claim 1 wherein the silica core has the following characteristic x-ray diffraction pattern: ______________________________________ Interplanar spacing d (Å) Relative Intensity ______________________________________ 11.2 ±0.2 m 10.1±0.2 m 6.73±0.2 w 5.75±0.1 w 5.61±0.1 w 5.03±0.1 w 4.62±0.1 w 4.39±0.08 w 3.86±0.07 vs 3.73±0.07 m 3.49±0.07 w 3.07 ±0.05 w 3.00 2.01±0.02 w ______________________________________

Claim 10

Process of claim 1 wherein the silica core is a silica having the following significant lines in its x-ray pattern: ______________________________________ Interplanar spacing d (Å) Relative Intensity ______________________________________ 11.9 ± 0.2 s 10.2 ± 0.2 m 4.76 ± 0.1 w 4.29 ± 0.08 vs 3.87 ± 0.07 vs 3.66 ± 0.07 w 3.49 ± 0.07 w 3.38 ± 0.07 m 3.20 ± 0.06 w 3.05 ± 0.05 w 2.64 ± 0.03 w ______________________________________

Claim 11

Process of claim 1 wherein the silica core alone and the catalyst composition display the significant x-ray diffraction lines of a ZSM-5 zeolite.

Claim 12

Process of claim 1 wherein the modified-silica zeolite has a formula (expressed in terms of the mole ratios of oxides) as follows: M.sub.2/n O:W.sub.2/x O:YSiO.sub.2 :zH.sub.2 O wherein M is at least one cation of valence n, W is the modifying element of valence x, Y is at least 5 and z is from 0 to 40.

Claim 13

Process of claim 11 wherein modifying element W is Al, B, Ga, Cr, Fe, V, Ti, Be, AS or a combination of two or more of those elements.

Claim 14

Process of claim 11 wherein the modified-silica zeolite is of the formula (expressed in terms of mole ratios of oxides): M.sub.2/n O:W'.sub.2 O.sub.3 :Y'SiO.sub.2 :zH.sub.2 O wherein W' is one or more of Al, Ga and B, Y' is 20-5000.

Claim 15

Process of claim 11 wherein the mean ratio of silicon to modifying element W or W' in the complete catalyst (expressed in terms of mole ratios of their oxides) is from 20 to 500.

Claim 16

Process of claim 1 wherein the silica core has a crystalline size of greater than 0.1μ mean diameter.

Claim 17

Process of claim 15 wherein the silica core has a crystallite size of from 0.5μ to 20μ mean diameter.

Claim 18

Process of claim 1 wherein the weight ratio of the silica core to the overlying modified-silica zeolite (expressed in terms of the weight ratio of the SiO 2 core to the SiO 2 in the reaction mixture for the modified-silica zeolite) is from 1:1 to 10:1.

Claim 19

Process of claim 17 wherein the weight ratio of the silica core to the overlying modified-silica is from 1:1 to 4:1.