Ionic liquid mediated elimination of acetonitrile from the olefin feed used in the production of ethers

• Main Authors: FORESTIERE, ALAIN, CADOURS, RENAUD, VALLEE, CHRISTOPHE
• Format: Patent
• Language: English; French; German
• Published: 18.06.2008
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; APPARATUS THEREFOR; CHEMISTRY; GENERAL METHODS OF ORGANIC CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; TRANSPORTING

Preparation of ethers comprises elimination of acetonitrile present in the hydrocarbon charge by liquid-liquid extraction, in an extraction zone using an extraction solvent i.e. a non-aqueous ionic liquid, before etherification. Preparation of ethers comprises elimination of acetonitrile present in the hydrocarbon charge by liquid-liquid extraction, in an extraction zone using an extraction solvent i.e. a non-aqueous ionic liquid of formula (Q +>A ->), before etherification. Q +>ammonium, phosphonium and/or sulfonium cation, preferably N-butylpyridinium, N-ethylpyridinium, pyridinium, ethyl-3-methyl-1-imidazolium, butyl-3-methyl-1-imidazolium, dipicrylamine-3-methyl-1-imidazolium, butyl-3-dimethyl-1,2-imidazolium, diethyl-pyrazolium, N-butyl-N-methylpyrrolidinium, trimethylphenyl-ammonium, tetrabutylphosphonium, tributyltetradecyl-phosphonium; and A ->anion suitable to form cation a liquid salt with the cation, preferably halides, nitrates, sulfates, alkylsulfates, phosphate, alkylphosphates, acetate, haloacetates, tetrafluoroborate, tetrachloroborate, hexafluorophosphate, trifluoro-tris-(pentafluoroethyl)phosphate, hexafluoroantimonate, fluorosulfonate, alkylsulfonates, perfluoroalkylsulfonates, bis(perfluoroalkylsulfonyl) amides, tris-trifluoromethanesulfonyl methylide of formula C(CF 3SO 2) 3 ->, arenesulfonates, tetra-(trifluoroacetoxy)-borate, bis-(oxalato)-borate, dicyanamide, tetraphenylborate or tetraphenylborates anions. An independent claim is included for the preparation of ethers from iso-olefin and alcohols comprising: elimination of elimination of acetonitrile present in the hydrocarbon charge by liquid-liquid extraction; mixing the obtained hydrocarbon fraction with an alcohol flow; etherification reaction of the obtained mixture in the presence of an ion exchange resin to obtain an ether-hydrocarbon-alcohol effluent; and separation of the effluent in a fractionating column into a first effluent enriched in ether and containing a part of excess alcohol and a second effluent enriched in hydrocarbons containing the other part of excess alcohol. Un procédé amélioré de fabrication d'éthers à partir d'une coupe oléfinique contenant au moins une iso-oléfine et d'un alcool comprend une étape d'élimination de l'acétonitrile présent dans la charge hydrocarbonée par extraction liquide-liquide, le solvant d'extraction étant un liquide ionique non aqueux de formule générale Q + A - , dans laquelle Q + est un cation ammonium, phosphonium et/ ou sulfonium, et A - un anion susceptible de former avec ledit cation un sel liquide. Avantageusement, le procédé selon l'invention permet de diviser généralement au moins par deux la quantité d'eau à l'entrée du réacteur d'éthérification et ainsi d'améliorer la pureté de l'éther produit.