# US 11,306,041 B2 · Catalytic synthesis of super linear alkenyl arenes using rhodium catalysts > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,306,041 B2 - Document ID: US11306041B2 - Status: Granted - Kind: B2 - Application number: 16/499,756 - Filed: 2018-03-30 - Published: 2021-06-03 - Granted: 2022-04-19 - Earliest claimed: 2017-03-30 - Assignees: University of Virginia Patent Foundation - Applicants: University of Virginia Patent Foundation - Inventors: William Schinski; Alan Goldman; Thomas B. Gunnoe; Michael S. Webster-Gardiner; Nichole Schwartz - Web page: https://patentgrep.com/patent/US11306041B2 ## CPC - C07C 2/66: Catalytic processes - C07C 17/266: of hydrocarbons and halogenated hydrocarbons - B01J 21/04: Alumina - B01J 21/08: Silica - B01J 23/42: Platinum - B01J 23/464: {Rhodium} - B01J 29/44: Noble metals - B01J 31/1815: {with more than one complexing nitrogen atom, e.g. bipyridyl, 2-aminopyridine} - B01J 31/183: {with more than one complexing nitrogen atom, e.g. phenanthroline} - B01J 31/2226: {Anionic ligands, i.e. the overall ligand carries at least one formal negative charge} - B01J 31/2291: {Olefins} - C07C 5/333: Catalytic processes - C07C 5/393: with cyclisation to an aromatic six-membered ring, e.g. dehydrogenation of n-hexane to benzene - C07C 5/41: Catalytic processes - C07C 41/30: by increasing the number of carbon atoms, e.g. by oligomerisation - B01J 2231/32: Addition reactions to C=C or C-C triple bonds - B01J 2531/0244: Pincer-type complexes, i.e. consisting of a tridentate skeleton bound to a metal, e.g. by one to three metal-carbon sigma-bonds - B01J 2531/822: Rhodium - B01J 2531/827: Iridium - C07C 2521/04: Alumina - C07C 2521/08: Silica - C07C 2523/46: Ruthenium, rhodium, osmium or iridium - C07C 2529/44: Noble metals - C07C 2531/22: Organic complexes - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS ## Abstract Catalytic methods for synthesis of super linear alkenyl arenes and alkyl arenes are provided. The methods are capable of synthesizing super linear alkyl and alkenyl arenes from simple arene and olefin starting materials and with high selectivity for linear coupling. Methods are also provided for making a 2,6-dimethylnapthalene (DMN) or 2,6-methylethylnapthalene (MEN). ## Claims ### Claim 1 A method of making alkenyl arenes, the method comprising contacting an arene and an olefin in the presence of an effective amount of a rhodium catalyst and an oxidant at an elevated temperature for a period of time to produce the alkenyl arenes, wherein the rhodium catalyst is a heterogeneous Rh(II) or Rh(III) catalyst. ### Claim 2 (depends on 1) The method according to claim 1, wherein a linear to branched ratio (L:B ratio) of the alkenyl arenes is about 2:1 to about 99:1. ### Claim 3 (depends on 1) The method according to claim 1, wherein the arene is a mono-substituted benzene; and wherein the alkenyl arenes comprise one or both of a meta-substituted alkenyl arene and a para-substituted alkenyl arene. ### Claim 4 (depends on 3) The method according to claim 3, wherein a total amount of the meta-substituted alkenyl arene and the para-substituted alkenyl arene is about 85 mol % to about 100 mol % based upon a total amount of the alkenyl arene. ### Claim 5 (depends on 3) The method according to claim 3, wherein the mono-substituted benzene comprises one or more of toluene, chlorobenzene, and anisole. ### Claim 6 (depends on 3) The method according to claim 3, wherein the olefin comprises one or more of propylene, 1-pentene, neohexene, and isobutylene. ### Claim 7 (depends on 3) The method according to claim 3, wherein the olefin comprises a linear or branched, substituted or unsubstituted alpha olefin having from 3 to about 30 carbon atoms. ### Claim 8 (depends on 1) The method according to claim 1, wherein the arene comprises a polyaromatic. ### Claim 9 (depends on 8) The method according to claim 8, wherein the polyaromatic is selected from the group consisting of substituted and unsubstituted naphthalene, anthracene, tetracene, and other polyaromatic compounds having from 2 to 5 fused aromatic rings. ### Claim 10 (depends on 1) The method according to claim 1, the method further comprising dehydrogenation of the alkenyl arenes to form alkyl arenes. ### Claim 11 (depends on 10) The method according to claim 10, wherein the hydrogenation comprises contacting the alkenyl arenes and hydrogen in the presence of a hydrogenation catalyst at a second elevated temperature for a second period of time to produce the alkyl arenes. ### Claim 12 (depends on 11) The method according to claim 11, wherein the second elevated temperature is about 100° C. to about 300° C. ### Claim 13 (depends on 11) The method according to claim 11, wherein the hydrogenation comprises combining the alkenyl arenes and the ethanol at an elevated pressure of about 100 psig to about 5000 psig. ### Claim 14 (depends on 11) The method according to claim 11, wherein the second period of time is about 1 hour to about 72 hours. ### Claim 15 (depends on 1) The method according to claim 1, wherein the arene is benzene; wherein the olefin is ethylene; and wherein the alkenyl arene is styrene. ### Claim 16 (depends on 15) The method according to claim 15, wherein the styrene is produced with over 95% yield and a ratio of styrene to trans-stilbene of at least 98:1. ### Claim 17 (depends on 1) The method according to claim 1, further comprising that the arene and olefin are contacted in the presence of the rhodium catalyst and an effective amount of an acid to improve one or both of a longevity of the rhodium catalyst and a linear to branched ratio (L:B ratio) of the alkenyl arenes. ### Claim 18 (depends on 1) A method of making a 2,6-dimethylnapthalene (DMN) or 2,6-methylethylnapthalene (MEN), the method comprising: making a pentenyl or hexenyl toluene by a method according to claim 1; and dehydroaromatization of the pentenyl or hexenyl toluene to form the DMN or MEN. ### Claim 19 (depends on 18) The method according to claim 18, wherein the dehydroaromatization comprises contacting the pentenyl or hexenyl toluene with a combination of a dehydrogenation catalyst and a zeolite catalyst. ### Claim 20 (depends on 19) The method according to claim 19, wherein the dehydrogenation catalyst is an iridium complex with a pincer-type ligand. ### Claim 21 (depends on 1) The method of claim 1, wherein the heterogeneous Rh(II) or Rh(III) catalyst is selected from Rh nanoparticles on SiO2, Rh nanoparticles on Al2O3, or Rh nanoparticles on a zeolite.