# US 4,394,362 A · Crystalline silicate particle having an aluminum-containing outer shell > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,394,362 A - Document ID: US4394362A - Status: Granted - Kind: A - Application number: 06/258,497 - Filed: 1981-04-28 - Granted: 1983-07-19 - Earliest claimed: 1981-04-28 - Assignees: Chevron Research Company - Inventors: Stephen J. Miller - Web page: https://patentgrep.com/patent/US4394362A ## CPC - B01J 29/40: of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively - C01B 33/2876: {from a reacting mixture containing an amine or an organic cation, e.g. a quaternary onium cation-ammonium, phosphonium, stibonium} - C10G 11/05: Crystalline alumino-silicates, e.g. molecular sieves - C10G 35/095: containing crystalline alumino-silicates, e.g. molecular sieves {(C10G35/065 takes precedence)} - C10G 49/08: containing crystalline alumino-silicates, e.g. molecular sieves - B01J 2229/62: in or on other molecular sieves - Y10S 423/22: MFI, e.g. ZSM-5. silicalite, LZ-241 - Y10S 423/29: MEL, e.g. ZSM-11 - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} - C10G: CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION (cracking to hydrogen or synthesis gas C01B; cracking or pyrolysis of hydrocarbon gases to individual hydrocarbons or mixtures thereof of definite or specified constitution C07C; cracking to cokes C10B); RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract Crystalline silicate particles having an aluminum-containing isostructural outer shell. The particles are prepared by first crystallizing crystalline silicate particles from a first reaction medium and thereafter crystallizing an isostructural outer shell onto said crystalline silicate particles from a reaction medium containing an increased source of aluminum. ## Claims ### Claim 1 A particle, comprising an inner portion and an outer portion disposed as a shell around said inner portion wherein said outer portion has the same crystal structure as said inner portion, said inner portion comprising an intermediate pore size crystalline silicate having a silica:alumina mole ratio greater than about 200:1, and said outer portion having a silica:alumina mole ratio of less than about 100:1 and wherein said particle is prepared by a process comprising: (1) initiating crystallization in a crystallization medium substantially free of aluminum to produce the intermediate pore size crystalline silicate; (2) adding a source of aluminum to said crystallization medium; and (3) crystallizing onto said crystalline silicate the isostructural outer portion which comprises alumina. ### Claim 2 A particle, comprising an inner portion and an outer portion disposed as a shell around said inner portion wherein said outer portion has the same crystal structure as said inner portion, said inner portion comprising an intermediate pore size crystalline silicate having a silica:alumina mole ratio greater than about 200:1, and said outer portion having a silica:alumina mole ratio of less than about 100:1 and wherein said particle is prepared by a process comprising: (1) crystallizing the intermediate pore size crystalline silicate from a first reaction medium substantially free of aluminum; (2) removing said crystalline silicate from said first reaction medium; (3) adding said crystalline silicate to a second reaction medium comprising sources of aluminum, and (4) crystallizing the isostructural, alumina containing outer layer onto said crystalline silicate. ### Claim 3 (depends on 2) The particle of claim 2 having the X-ray diffraction pattern of ZSM-5. ### Claim 4 (depends on 2) The particle of claim 2 having the X-ray diffraction pattern of ZSM-11. ### Claim 5 A process for preparing a particle, comprising an inner portion and an outer portion disposed as a shell around said inner portion wherein said outer portion has the same crystal structure as said inner portion, said inner portion comprising an intermediate pore size crystalline silicate having a silica:alumina mole ratio greater than about 200:1, and said outer portion having a silica:alumina mole ratio of less than about 100:1, comprising: (1) initiating crystallization in a crystallization medium substantially free of aluminum to produce the intermediate pore size crystalline silicate; (2) adding a source of aluminum to said crystallization medium; and (3) crystallizing onto said crystalline silicate the isostructural outer portion which comprises alumina. ### Claim 6 (depends on 5) The process of claim 5 wherein the reaction mixture comprises sources of organic cation, silica and hydroxide ion. ### Claim 7 (depends on 6) The process of claim 6 wherein the source of hydroxide ion is sodium hydroxide. ### Claim 8 (depends on 6) The process of claim 6 wherein in step (2) the organic ion to SiO.sub.2 mole ratio is reduced from that in step (1). ### Claim 9 (depends on 7) The process of claim 7 wherein in step (2) the hydroxide content is lower than that in step (1). ### Claim 10 (depends on 5) The process of claim 5 wherein step (3) is performed at a temperature of from about 100.degree. C. to 120.degree. C. and at a pH of from 10 to 12. ### Claim 11 (depends on 5) The process of claim 5 wherein said crystalline silicate is silicalite having a silica:alumina mole ratio greater than about 200:1 and said isostructural outer portion has a silica:alumina mole ratio less than about 100:1. ### Claim 12 A process for preparing a particle, comprising an inner portion and an outer portion disposed as a shell around said inner portion wherein said outer portion has the same crystal structure as said inner portion, said inner portion comprising an intermediate pore size crystalline silicate having a silica:alumina mole ratio greater than about 200:1, and said outer portion having a silica:alumina mole ratio of less than about 100:1, comprising: (1) crystallizing the intermediate pore size crystalline silicate from a first reaction medium substantially free of aluminum; (2) removing said crystalline silicate from said first reaction medium; (3) adding said crystalline silicate to a second reaction medium comprising sources of aluminum, and (4) crystallizing the isostructural, alumina containing outer layer onto said crystalline silicate. ### Claim 13 (depends on 12) The process of claim 12 wherein the first and second reaction mixtures comprise sources of organic cation, silica and hydroxide ion. ### Claim 14 (depends on 13) The process of claim 13 wherein the source of hydroxide ion is sodium hydroxide. ### Claim 15 (depends on 13) The process of claim 13 wherein in step (3) the organic ion to SiO.sub.2 mole ratio is reduced from that in step (1). ### Claim 16 (depends on 14) The process of claim 14 wherein in step (3) the hydroxide content is lower than that in step (1). ### Claim 17 (depends on 12) The process of claim 12 wherein step (4) is performed at a temperature of from about 100.degree. C. to 120.degree. C. and at a pH of from 10 to 12. ### Claim 18 (depends on 12) The process of claim 12 wherein said crystalline silicate is silicalite having a silica:alumina ratio greater than about 200:1 and said isostructural outer portion has a silica:alumina mole ratio less than about 100:1. ### Claim 19 (depends on 2) The composition of claim 2 wherein the silica:alumina mole ratio of said inner portion is greater than about 500:1. ### Claim 20 (depends on 2) The composition of claim 2 wherein the silica:alumina mole ratio of said inner portion is greater than about 1000:1.