Provided is a method for recovering, by pressure swing adsorption, unreacted olefins from a stream of a chemical reaction process in which an olefin is used as a material, the method enables desorption of gas at a relatively high desorption operation pressure, more preferably at a pressure not lower than the atmospheric pressure, and enables reuse of a separation agent. As the separation agent, a metal complex is used, in which pressure P3 at which a local maximum of dA/dP is obtained during adsorption and pressure P4 at which a local maximum of dA/dP is obtained during desorption are located between an adsorption operation pressure P1 and a desorption operation pressure P2, where dA/dP represents a value obtained by differentiating A by P, assuming that an olefin adsorption amount (A) is a function of an adsorption pressure (P), i.e., A=f(P), on an adsorption isotherm indicating the pressure (P) and the adsorption amount (A).

Provided is a method for recovering, by pressure swing adsorption, unreacted olefins from a stream of a chemical reaction process in which an olefin is used as a material, the method enables desorption of gas at a relatively high desorption operation pressure, more preferably at a pressure not lower than the atmospheric pressure, and enables reuse of a separation agent. As the separation agent, a metal complex is used, in which pressure P3 at which a local maximum of dA/dP is obtained during adsorption and pressure P4 at which a local maximum of dA/dP is obtained during desorption are located between an adsorption operation pressure P1 and a desorption operation pressure P2, where dA/dP represents a value obtained by differentiating A by P, assuming that an olefin adsorption amount (A) is a function of an adsorption pressure (P), i.e., A=f(P), on an adsorption isotherm indicating the pressure (P) and the adsorption amount (A).

Provided is a method for recovering, by pressure swing adsorption, unreacted olefins from a stream of a chemical reaction process in which an olefin is used as a material, the method enables desorption of gas at a relatively high desorption operation pressure, more preferably at a pressure not lower than the atmospheric pressure, and enables reuse of a separation agent. As the separation agent, a metal complex is used, in which pressure P3 at which a local maximum of dA/dP is obtained during adsorption and pressure P4 at which a local maximum of dA/dP is obtained during desorption are located between an adsorption operation pressure P1 and a desorption operation pressure P2, where dA/dP represents a value obtained by differentiating A by P, assuming that an olefin adsorption amount (A) is a function of an adsorption pressure (P), i.e., A=f(P), on an adsorption isotherm indicating the pressure (P) and the adsorption amount (A).

Disclosed are air-stable small-molecule adsorbents trimeric [Cu—Br].sub.3 and [Cu—H].sub.3 that undergo a reversible solid-state molecular rearrangements to [Cu—Br.(alkene)].sub.2 and [Cu—H.(alkene)].sub.2 dimers. The reversible solid-state rearrangement allows one to break adsorbent design trade-offs and achieve low heat of adsorption while retaining high selectivity and uptake.

Disclosed are air-stable small-molecule adsorbents trimeric [Cu—Br].sub.3 and [Cu—H].sub.3 that undergo a reversible solid-state molecular rearrangements to [Cu—Br.(alkene)].sub.2 and [Cu—H.(alkene)].sub.2 dimers. The reversible solid-state rearrangement allows one to break adsorbent design trade-offs and achieve low heat of adsorption while retaining high selectivity and uptake.

A method for the recovery paraxylene with reduced crystallization. Paraxylene is recovered from a mixture of C8 aromatic hydrocarbons in a pressure swing adsorption zone and a crystallization zone. The invention provides for lower throughput through the crystallization zone, resulting in lower capital costs, reduced electricity in operating separation equipment, as well as reduced refrigeration duty.

A method for the recovery paraxylene with reduced crystallization. Paraxylene is recovered from a mixture of C8 aromatic hydrocarbons in a pressure swing adsorption zone and a crystallization zone. The invention provides for lower throughput through the crystallization zone, resulting in lower capital costs, reduced electricity in operating separation equipment, as well as reduced refrigeration duty.

A method for the recovery paraxylene with reduced crystallization. Paraxylene is recovered from a mixture of C8 aromatic hydrocarbons in a pressure swing adsorption zone and a crystallization zone. The invention provides for lower throughput through the crystallization zone, resulting in lower capital costs, reduced electricity in operating separation equipment, as well as reduced refrigeration duty.

A method for recovering paraxylene from a mixture of aromatic hydrocarbons. The process uses a pressure swing adsorption zone followed by a paraxylene recovery zone. The invention provides for lower throughput through the paraxylene recovery zone, resulting in lower capital costs and operating costs.

A method for recovering paraxylene from a mixture of aromatic hydrocarbons. The process uses a pressure swing adsorption zone followed by a paraxylene recovery zone. The invention provides for lower throughput through the paraxylene recovery zone, resulting in lower capital costs and operating costs.