Disclosed herein are modified zeolites and methods for making modified zeolites. In one or more embodiments disclosed herein, a zeolite may include a microporous framework comprising a plurality of micropores having diameters of less than or equal to 2 nm. The microporous framework may include at least silicon atoms and oxygen atoms. The modified zeolite may further include organometallic moieties each bonded to bridging oxygen atoms. The organometallic moieties may include a zirconium atom. The zirconium atom may be bonded to a bridging oxygen atom, and the bridging oxygen atom may bridge the zirconium atom of the organometallic moiety and a silicon atom of the microporous framework.

Disclosed herein are modified zeolites and methods for making modified zeolites. In one or more embodiments disclosed herein, a modified zeolite may include a microporous framework including a plurality of micropores having diameters of less than or equal to 2 nm. The microporous framework may include at least silicon atoms and oxygen atoms. The modified zeolite may further include organometallic moieties each bonded to bridging oxygen atoms. The organometallic moieties may include a platinum atom. The platinum atom may be bonded to a bridging oxygen atom, and the bridging oxygen atom may bridge the platinum atom of the organometallic moiety and a silicon atom of the microporous framework.

Disclosed herein are modified zeolites and methods for making modified zeolites. In one or more embodiments disclosed herein, a modified zeolite may include a microporous framework including a plurality of micropores having diameters of less than or equal to 2 nm. The microporous framework may include at least silicon atoms and oxygen atoms. The modified zeolite may further include organometallic moieties each bonded to bridging oxygen atoms. The organometallic moieties may include a platinum atom. The platinum atom may be bonded to a bridging oxygen atom, and the bridging oxygen atom may bridge the platinum atom of the organometallic moiety and a silicon atom of the microporous framework.

Disclosed herein are modified zeolites and methods for making modified zeolites. In one or more embodiments disclosed herein, a modified zeolite may include a microporous framework comprising a plurality of micropores having diameters of less than or equal to 2 nm. The microporous framework may include at least silicon atoms and oxygen atoms. The modified zeolite may further include organometallic moieties each bonded to bridging oxygen atoms. The organometallic moieties may include a titanium atom. The titanium atom may be bonded to a bridging oxygen atom, and the bridging oxygen atom may bridge the titanium atom of the organometallic moiety and a silicon atom of the microporous framework.

Embodiments of the present disclosure relate to zeolites and method for making such zeolites. According to embodiments disclosed herein, a zeolite may have a microporous framework including a plurality of micropores having diameters of less than or equal to 2 nm and a plurality of mesopores having diameters of greater than 2 nm and less than or equal to 50 nm. The microporous framework may include an MFI framework type. The microporous framework may include silicon atoms, aluminum atoms, oxygen atoms, and transition metal atoms. The transition metal atoms may be dispersed throughout the entire microporous framework.

A plastic catalytic pyrolysis process that can produce high yields of ethylene, propylene and other light olefins from waste plastics is disclosed. The catalytic product stream is quenched to below catalytic pyrolysis temperature quickly after exiting the reactor or bulk separation from the catalyst. Quench preserves selectivity of light olefinic monomers. The catalytic pyrolysis process can be operated in a single stage or a two-stage process.

Disclosed herein are modified zeolites and methods for making modified zeolites. In one or more embodiments disclosed herein, a modified zeolite may include a microporous framework including a plurality of micropores having diameters of less than or equal to 2 nm. The microporous framework may include at least silicon atoms and oxygen atoms. The modified zeolite may further include organometallic moieties each bonded to a nitrogen atom of a secondary amine functional group comprising a nitrogen atom and a hydrogen atom. The organometallic moieties may comprise a hafnium atom that is bonded to the nitrogen atom of the secondary amine functional group. The nitrogen atom of the secondary amine function group may bridge the hafnium atom of the organometallic moiety and a silicon atom of the microporous framework.

Methods for cracking a hydrocarbon feed stream include contacting a hydrocarbon feed stream with a catalyst system in a catalytic cracking unit having a flowing gas stream to obtain a cracking product containing light olefins. The catalyst system includes at least a base catalyst. The base catalyst includes a pentasil zeolite. The pentasil zeolite includes from 0.01% to 5% by mass lithium atoms, as calculated on an oxide basis, based on the total mass of the pentasil zeolite. The flowing gas stream comprises hydrogen and, optionally, at least one additional carrier gas.

Methods for cracking a hydrocarbon feed stream include contacting a hydrocarbon feed stream with a catalyst system in a catalytic cracking unit having a flowing gas stream to obtain a cracking product containing light olefins. The catalyst system includes at least a base catalyst. The base catalyst includes a pentasil zeolite. The pentasil zeolite includes from 0.01% to 5% by mass lithium atoms, as calculated on an oxide basis, based on the total mass of the pentasil zeolite. The flowing gas stream comprises hydrogen and, optionally, at least one additional carrier gas.

A fibrous hierarchical zeolite includes a framework comprising aluminum atoms, silicon atoms, and oxygen atoms, the framework further comprising a plurality of micropores and a plurality of mesopores. The framework comprises no Brønsted acid activity.