Olefin isomerization

A process for making internal olefins comprising:

• (A) forming a reaction mixture comprising (1) at least one α-olefin having from 4 to 25 carbons, (2) at least one acid catalyst selected from the group consisting of rare earth fluorinated alkyl sulfonates, organic sulfonic acids, fluoroalkyl sulfonic acids, metal sulfonates, metal trifluoroacetates, and combinations thereof, and (3) at least one ionic liquid comprised of an ammonium cation and an anion having the Formula:
• wherein:
• (i) Z is —(CH2)n—, wherein n is an integer from 2 to 12;
• (ii) R2, R3 and R4 taken independently are H, —CH3, —CH2CH3 or C3 to C6 straight-chain or branched monovalent alkyl;
• and
• (iii) A− is R5—SO3− or (R6—SO2)2N−;
• wherein R5 and R6 are independently selected from the group consisting of:
• (a) —CH3, —C2H5, or C3 to C25 straight-chain, branched or cyclic alkane or alkene, optionally substituted with at least one member selected from the group consisting of Cl, Br, F, I, OH, NH2 and SH;
• (b) —CH3, —C2H5, or C3 to C25 straight-chain, branched or cyclic alkane or alkene comprising one to three heteroatoms selected from the group consisting of O, N and S, and optionally substituted with at least one member selected from the group consisting of Cl, Br, F, I, OH, NH2 and SH;
• (C) C6 to C25 unsubstituted aryl or unsubstituted heteroaryl having one to three heteroatoms independently selected from the group consisting of O, N and S;
• and
• (d) C6 to C25 substituted aryl or substituted heteroaryl having one to three heteroatoms independently selected from the group consisting of O, N and S;
• and wherein said substituted aryl or substituted heteroaryl has one to three substituents independently selected from the group consisting of:
• (1) —CH3, —C2H5, or C3 to C25 straight-chain, branched or cyclic alkane or alkene, optionally substituted with at least one member selected from the group consisting of Cl, Br, F, I, OH, NH2 and SH,
• (2) OH,
• (3) NH2, and
• (4) SH;
• thereby forming an isomer phase comprising at least one internal olefin and an ionic liquid phase that comprises the at least one acid catalyst;
• and
• B) separating the isomer phase from the ionic liquid phase, thereby forming a separated ionic liquid phase.