Synthesis of terminal alkenes from internal alkenes and ethylene via olefin metathesis

An olefin metathesis process comprising contacting an olefinic substrate comprising at least one internal olefin and further comprising a mixture of mono-, di-, and tri-glycerides with ethylene in the presence of a ruthenium alkylidene metathesis catalyst under reaction conditions effective to prepare a metathesis product having a terminal olefin, wherein the metathesis catalyst has the structure of formula (IIa):

• wherein:
• M is Ru;
• X1 and X2 are anionic ligands;
• R1 is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl;
• Q is selected from the group consisting of heteroatom-containing hydrocarbylene and substituted heteroatom-containing hydrocarbylene, wherein M is connected to a heteroatom, wherein a five or six member ring is formed with M and the heteroatom, and wherein two or more substituents on adjacent atoms within Q may be taken together to form an additional, optionally substituted cyclic structure;
• n1 is zero or 1;
• L1 has the structure of formula (IIIb):
• L3 is a neutral electron donating ligand;
• wherein Ar1 is an aryl substituted with at least one group selected from the group consisting of C2-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C5-C12 aryl, C6-C12 aralkyl, and C6-C12 alkaryl;
• α is an optional double bond;
• and R10, R11, R13, R14, R15, and R16 are independently selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl, wherein any two or more of Ar1, R10, R11, R13, R14, R15, and R16 may be taken together to form a cyclic group, and provided that R14 and R16 are not present if α is present.

An olefin metathesis process comprising contacting an olefinic substrate comprising a seed oil or a composition derived from a seed oil and further comprising at least one internal olefin, with ethylene in the presence of a ruthenium alkylidene metathesis catalyst under reaction conditions effective to prepare a metathesis product having a terminal olefin, wherein the metathesis catalyst has the structure of formula (IIa):

• wherein:
• M is Ru;
• X1 and X2 are anionic ligands;
• R1 is selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl;
• Q is selected from the group consisting of heteroatom-containing hydrocarbylene and substituted heteroatom-containing hydrocarbylene, wherein M is connected to a heteroatom, wherein a five or six member ring is formed with M and the heteroatom, and wherein two or more substituents on adjacent atoms within Q may be taken together to form an additional, optionally substituted cyclic structure;
• n1 is zero or 1;
• L1 has the structure of formula (IIIb):
• L3 is a neutral electron donating ligand;
• wherein Ar1 is an aryl substituted with at least one group selected from the group consisting of C2-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C5-C12 aryl, C6-C12 aralkyl, and C6-C12 alkaryl;
• α is an optional double bond;
• R10, R11, R13, R14, R15, and R16 are independently selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl, wherein any two or more of Ar1, R10, R11, R13, R14, R15, and R16 may be taken together to form a cyclic group, and provided that R14 and R16 are not present if α is present;
• and
• wherein at least about 50% of the metathesis reaction products comprise a terminal olefin and further wherein at least about 50% of the internal olefins initially present in the reaction mixture are converted to terminal olefins.

A method for synthesizing a metathesis product having a terminal olefin, the method comprising contacting, in the presence of a metathesis catalyst, an olefinic substrate comprised of at least one internal olefin with ethylene, wherein the catalyst is present in an amount that is less than about 1000 ppm relative to the amount of the olefinic substrate, and wherein the metathesis catalyst has the structure of formula (XII):

• wherein:
• t is zero;
• M is Ru;
• X1 and X2 are anionic ligands;
• R1 and R2 are independently selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl;
• Z3 is a cationic moiety selected from the group consisting of P(R2)3 and N(R2)3;
• Y is a non-coordinating anion;
• and
• L1 is a carbene ligand with the structure of formula (IIIb):
• wherein Ar1 is an aryl substituted with at least one group selected from the group consisting of C2-C12 alkyl, C2-C12 alkenyl, C2-C12 alkynyl, C5-C12 aryl, C6-C12 aralkyl, and C6-C12 alkaryl;
• α is an optional double bond;
• and R10, R11, R13, R14, R15, and R16 are independently selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl, wherein any two or more of Ar1, R10, R11, R13, R14, R15, and R16 may be taken together to form a cyclic group, and provided that R14 and R16 are not present if α is present.