Back to results
US 9,914,700 B2Granted
Enhanced extraction of impurities from mixture comprising nitriles
AssigneeInvista North America S.A R.L.
InventorWilliam J. Tenn, III
Life of this patent
Estimating the term…
Abstract
Disclosed herein are methods for recovering phosphorus-containing ligand from mixtures comprising organic mononitriles and organic dinitriles, using liquid-liquid extraction. Also disclosed are treatments to enhance extractability of the phosphorus-containing ligand.
Claims15
A process for recovering a catalyst and adiponitrile (ADN) from a mixture comprising adiponitrile, 3-pentenenitrile (3PN), a Lewis acid and a catalyst, said process comprising the steps of:
- (a) providing a countercurrent multistage extraction zone comprising at least three mixer-settlers connected in series;
- (b) introducing said mixture comprising ADN, 3PN, Lewis acid and a catalyst to a first terminal mixer-settler in the series;
- (c) introducing an extraction solvent into the second terminal mixer-settler in the series;
- (d) forming a light phase comprising extraction solvent and a heavy phase comprising ADN and 3PN in the settling sections of each of the mixer-settlers;
- (e) flowing the heavy phase progressively from the first terminal mixer-settler through each of the mixer-settlers and into the second terminal mixer-settler;
- (f) flowing the light phase progressively from the second terminal mixer-settler through each of the mixer-settlers and into the first terminal mixer-settler;
- (g) withdrawing the light phase comprising extraction solvent and extracted catalyst from the first terminal mixer-settler;
- (h) withdrawing the heavy phase comprising ADN and 3PN from the second terminal mixer-settler;
- (i) distilling the withdrawn light phase from step (g) to separate extraction solvent from catalyst;
- and
- (j) distilling the withdrawn heavy phase from step (h) to separate ADN from 3PN,
- wherein the catalyst comprises zero valent nickel and a phosphorus-containing ligand,
- wherein a polyamine is added to the mixing section of the first terminal mixer-settler to form a precipitate comprising a complex of the Lewis acid with the polyamine,
- wherein the precipitate is dispersed in the heavy phase in the settling section of the first mixer-settler,
- wherein the precipitate is entrained in the flow of heavy phase through the series of mixer-settlers, and
- wherein the precipitate is withdrawn from the second terminal mixer-settler, along with the heavy phase.
13 more elements
Dependencies are inferred from the claim text.