# US 8,785,645 B2 · Method for synthesizing bio-based pyridine and picolines > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,785,645 B2 - Document ID: US8785645B2 - Status: Granted - Kind: B2 - Application number: 13/505,751 - Filed: 2010-10-22 - Published: 2012-11-08 - Granted: 2014-07-22 - Earliest claimed: 2009-11-04 - Assignees: Arkema France - Applicants: Jean-Luc Dubois; Jean-Francois Devaux - Inventors: Jean-Luc Dubois; Jean-Francois Devaux - Web page: https://patentgrep.com/patent/US8785645B2 ## CPC - C07D 213/12: from unsaturated compounds - C07D 213/10: from acetaldehyde or cyclic polymers thereof - C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08) ## Abstract The present invention relates to a method for synthesizing bio-based pyridine and picolines, said method including at least the following steps: a first step involving subjecting a glycerol filler, created from the methanolysis of vegetable oils or animal fats, to a dehydration reaction leading to acrolein; a second step involving partial condensation of the effluent from the first step so as to separate a water-rich flow as well as an acrolein-rich flow; and a third step involving reacting the acrolein from the preceding step with acetaldehyde in the presence of ammonia so as to obtain, by means of a condensation reaction, the bio-based pyridine and picolines. ## Claims ### Claim 1 A process for synthesizing biosourced pyridine and picolines, comprising: a) subjecting a glycerol charge derived from methanolysis of plant oils or animal fats to a dehydration reaction leading to acrolein according to the reaction CH2OH—CHOH—CH2OH→CH2═CH—CHO+2H2O and then b) partially condensing of the effluent derived from a), to separate a stream rich in water and a stream rich in acrolein, and c) reacting the acrolein obtained from b) with acetaldehyde, in the presence of ammonia, and in gaseous phase at a pressure between 0.5 and 10 bar to obtain, via a condensation reaction, biosourced pyridine and picolines. ### Claim 2 (depends on 1) The process as claimed in claim 1, wherein a) is performed in a reactor in gas phase at a temperature ranging from 150° C. to 500° C., and a pressure of between 1 and 5 bar in the presence of a solid acid catalyst that is insoluble in the reaction medium, with a Hammett acidity, H0, of less than +2 and chosen from natural or synthetic siliceous materials or acidic zeolites; mineral supports, oxides coated with mono-, di-, tri- or polyacidic inorganic acids, mixed oxides, or heteropolyacids or salts of heteropolyacids. ### Claim 3 (depends on 1) The process as claimed in claim 1, wherein during b), the gaseous effluent obtained from dehydration is subjected, to “quench” cooling, in a condensation unit (2) operating at a temperature generally of between 0 and 90° C., separating out at the bottom an aqueous solution comprising heavy compounds, acrylic acid, acetic acid, glycerol polyethers, glycerol acetals and residual glycerol, and at the top a gaseous fraction containing acrolein, propionaldehyde, acetaldehyde and unreacted gases O2 and N2 and also uncondensable gases CO and CO2, the head fraction then being subjected to a purification to obtain a desired quality of acrolein, with or without separation of the acetaldehyde, which may be subjected to the third step. ### Claim 4 (depends on 3) The process as claimed in claim 3, wherein said head fraction is sent to a second absorption column (4), purging at the top of the column uncondensable compounds via line (14) and separating out at the bottom an aqueous acrolein solution also containing the by-products. ### Claim 5 (depends on 4) The process as claimed in claim 4, wherein the aqueous acrolein solution derived from (4) is sent to a distillation column (5) where an acrolein-rich fraction containing acetaldehyde is separated out at the top (87) and an aqueous solution is separated out at the bottom (9) and is recycled into the absorption column (4). ### Claim 6 (depends on 4) The process as claimed in claim 4, wherein the aqueous acrolein solution obtained from (4) is sent to a distillation column (5), where a light fraction enriched in acetaldehyde is separated out at the top (8) and an aqueous acrolein solution is separated out at the bottom and is sent into a second column (6) where a fraction enriched in acrolein is separated out at the top (7) and an aqueous solution is separated out at the bottom (9) and is recycled into the absorption column (4). ### Claim 7 (depends on 4) The process as claimed in claim 4, wherein the aqueous acrolein solution obtained from (4) is sent to a distillation column (5) where a light fraction containing acetaldehyde is separated out at the top (8), and a fraction (7) enriched in acrolein is withdrawn laterally in an intermediate zone, and an aqueous solution is separated out at the bottom (9) and is recycled into the absorption column (4). ### Claim 8 (depends on 1) The process as claimed in claim 1, wherein during c), the acrolein obtained in b) is reacted in a reactor (15) with acetaldehyde in the presence of ammonia to obtain, via a condensation reaction, biosourced pyridine and picolines, this reaction being performed in the gaseous phase at a temperature of between 300 and 600° C., at an hourly space velocity (HSV) of 500 to 5000 h−1 and in the presence of a solid acid catalyst consisting of a silica-alumina optionally comprising a promoter. ### Claim 9 (depends on 1) The process as claimed in claim 1, wherein acetaldehyde entering the reaction is partly derived from a) and partly added during c). ### Claim 10 (depends on 1) The process as claimed in claim 1, wherein acetaldehyde added is obtained from bioethanol. ### Claim 11 (depends on 1) The process as claimed in claim 1, wherein acetaldehyde is added to the reaction medium in an amount such that the acrolein/acetaldehyde mole ratio is between 0.8 and 1.2, and ammonia is added in an amount such that the ammonia/acrolein+acetaldehyde mole ratio is between 2 and 20. ### Claim 12 (depends on 6) The process as claimed in claim 6, a portion of acrolein-rich stream is withdrawn at (7′), such that the remaining amount of acrolein stream sent to a reactor (15) where acrolein from b) is reacted with acetaldehyde, such that the acrolein (7)/acetaldehyde (8) mole ratio is between 0.8 and 1.2, this being done while dispensing with additional feed. ### Claim 13 (depends on 2) The process according to claim 2, wherein a) is performed at a temperature of 250-350° C. ### Claim 14 (depends on 8) The process according to claim 8, wherein the solid catalyst has a Si/Al ratio greater than 10. ### Claim 15 (depends on 11) The process according to claim 11, wherein the acrolein/acetaldehyde ratio is 0.9 to 1.1.