Described herein are compositions having an eight-membered monocyclic unsaturated hydrocarbon, methods and system to separate the eight-membered monocyclic unsaturated hydrocarbon at from a hydrocarbon mixture including additional nonlinear unsaturated C.sub.8H.sub.2m hydrocarbons with 4?m?8, by contacting the hydrocarbon mixture with a 10-ring pore molecular sieve having a sieving channel with a 10-ring sieving aperture with a minimum crystallographic free diameter greater than 3 ? and a ratio of the maximum crystallographic free diameter to the minimum crystallographic free diameter between 1 and 2, the molecular sieve having a T1/T2 ratio?20:1 wherein T1 is an element independently selected from Si and Ge, and T2 is an element independently selected from Al, B and Ga, the 10-ring pore molecular sieve further having a counterion selected from NH.sub.4.sup.+, Li.sup.+, Na.sup.+, K.sup.+ and Ca.sup.++.

Described herein are compositions having an eight-membered monocyclic unsaturated hydrocarbon, methods and system to separate the eight-membered monocyclic unsaturated hydrocarbon at from a hydrocarbon mixture including additional nonlinear unsaturated C.sub.8H.sub.2m hydrocarbons with 4?m?8, by contacting the hydrocarbon mixture with a 10-ring pore molecular sieve having a sieving channel with a 10-ring sieving aperture with a minimum crystallographic free diameter greater than 3 ? and a ratio of the maximum crystallographic free diameter to the minimum crystallographic free diameter between 1 and 2, the molecular sieve having a T1/T2 ratio?20:1 wherein T1 is an element independently selected from Si and Ge, and T2 is an element independently selected from Al, B and Ga, the 10-ring pore molecular sieve further having a counterion selected from NH.sub.4.sup.+, Na.sup.+, K.sup.+ and Ca.sup.++.

Described herein are compositions having an eight-membered monocyclic unsaturated hydrocarbon, methods and system to separate the eight-membered monocyclic unsaturated hydrocarbon at from a hydrocarbon mixture including additional nonlinear unsaturated C.sub.8H.sub.2m hydrocarbons with 4?m?8, by contacting the hydrocarbon mixture with a 10-ring pore molecular sieve having a sieving channel with a 10-ring sieving aperture with a minimum crystallographic free diameter greater than 3 ? and a ratio of the maximum crystallographic free diameter to the minimum crystallographic free diameter between 1 and 2, the molecular sieve having a T1/T2 ratio?20:1 wherein T1 is an element independently selected from Si and Ge, and T2 is an element independently selected from Al, B and Ga, the 10-ring pore molecular sieve further having a counterion selected from NH.sub.4.sup.+, Na.sup.+, K.sup.+ and Ca.sup.++.

Described herein are compositions having an eight-membered monocyclic unsaturated hydrocarbon, methods and system to separate the eight-membered monocyclic unsaturated hydrocarbon from a hydrocarbon mixture including additional nonlinear unsaturated C.sub.8H.sub.2m hydrocarbons with 4?m?8, by contacting the hydrocarbon mixture with a 10-ring pore molecular sieve having a sieving channel with a 10-ring sieving aperture with a minimum crystallographic free diameter greater than 3 ? and a ratio of the maximum crystallographic free diameter to the minimum crystallographic free diameter between 1 and 2, the molecular sieve having a T1/T2 ratio?20:1 wherein T1 is an element independently selected from Si and Ge, and T2 is an element independently selected from Al, B and Ga, the 10-ring pore molecular sieve further having a counterion selected from NH.sub.4.sup.+, Li.sup.+, Na.sup.+, K.sup.+ and Ca.sup.++.

Described herein are compositions having an eight-membered monocyclic unsaturated hydrocarbon, methods and system to separate the eight-membered monocyclic unsaturated hydrocarbon from a hydrocarbon mixture including additional nonlinear unsaturated C.sub.8H.sub.2m hydrocarbons with 4m8, by contacting the hydrocarbon mixture with a 10-ring pore molecular sieve having a sieving channel with a 10-ring sieving aperture with a minimum crystallographic free diameter greater than 3 and a ratio of the maximum crystallographic free diameter to the minimum crystallographic free diameter between 1 and 2, the molecular sieve having a T1/T2 ratio20:1 wherein T1 is an element independently selected from Si and Ge, and T2 is an element independently selected from Al, B and Ga, the 10-ring pore molecular sieve further having a counterion selected from NH.sub.4.sup.+, Li.sup.+, Na.sup.+, K.sup.+ and Ca.sup.++.

Described herein are compositions having an eight-membered monocyclic unsaturated hydrocarbon, methods and system to separate the eight-membered monocyclic unsaturated hydrocarbon at from a hydrocarbon mixture including additional nonlinear unsaturated C.sub.8H.sub.2m hydrocarbons with 4m8, by contacting the hydrocarbon mixture with a 10-ring pore molecular sieve having a sieving channel with a 10-ring sieving aperture with a minimum crystallographic free diameter greater than 3 and a ratio of the maximum crystallographic free diameter to the minimum crystallographic free diameter between 1 and 2, the molecular sieve having a T1/T2 ratio 20:1 wherein T1 is an element independently selected from Si and Ge, and T2 is an element independently selected from Al, B and Ga, the 10-ring pore molecular sieve further having a counterion selected from NH.sub.4.sup.+, Li.sup.+, Na.sup.+, K.sup.+ and Ca.sup.++.