Process for separating one or more components from a mixture
The invention relates to a process for separating one or more components from a mixture by a membrane separation in which—depending on the component to be separated—an acid or a base is added to the mixture before the membrane separation.
1. A process for separating a homogeneous catalyst system that contains at least one metal from groups 8 to 10 of the periodic table of elements or a compound thereof and a phosphorus-containing ligand, from a reaction solution by a membrane separation, the process comprising:
adding an acid to the reaction solution, to obtain a mixture, and
separating the mixture by membrane separation, to result in the homogeneous catalyst system being depleted in the resulting permeate stream and enriched in a resulting retentate stream,
wherein at least one component of the homogeneous catalyst system contains at least one basic functional group,
wherein the acid is added in an amount of ≥0.1% by weight, based on the total weight of the mixture, wherein the at least one component to be separated has a basic functional group, and
wherein the acid is a Brønsted or Lewis acid, the Brønsted acid being selected from the group consisting of perchloric acid sulfuric acid, phosphoric acid, methylphosphonic acid or a sulfonic acid and the Lewis acid being selected from the group consisting of aluminium triflate, aluminium chloride, aluminium hydride, trimethylaluminium, tris(pentaflurophenyl)borane, boron trifluoride, boron trichloride, titanium(IV) isopropoxide, BU 2 SnO, BuSn(O)OH, or mixtures thereof.
2. The process according to claim 1 , wherein the acid is added to the mixture in an amount of ≥0.1% by weight and <5% by weight.
3. The process according to claim 1 , wherein the acid is a Lewis acid selected from the group consisting of aluminium triflate, aluminium chloride, aluminium hydride, trimethylaluminium, tris(pentafluorophenyl)borane, boron trifluoride, boron trichloride, and mixtures thereof.
4. The process according to claim 1 , wherein the acid is a Brønsted or Lewis acid, the Brønsted acid being selected from the group consisting of perchloric acid, phosphoric acid, methylphosphonic acid or a sulfonic acid and the Lewis acid being selected from the group consisting of aluminium triflate, aluminium chloride, aluminium hydride, trimethylaluminium, tris(pentaflurophenyl)borane, boron trifluoride, boron trichloride, titanium(IV) isopropoxide, Bu 2 SnO, BuSn(O)OH, or mixtures thereof.
5. The process according to claim 1 , wherein the phosphorus-containing ligand of the homogeneous catalyst system has a mono- or bidentate structure.
6. The process according to claim 1 , wherein the phosphorus-containing ligand is a benzene-based diphosphine compound.
7. The process according to claim 1 , wherein a ceramic membrane material is used in the membrane separation.
8. The process according to claim 7 , wherein the ceramic membrane material comprises or consists of aluminium oxide, SiO 2 , TiO 2 , ZrO 2 or mixtures of these materials.
9. The process according to claim 1 , wherein a polymer-based membrane material is used in the membrane separation and wherein the polymer-based membrane material includes at least one separation-active layer.
10. The process according to claim 9 , wherein the polymer-based material as the separation-active layer includes a material selected from the group consisting of polyimide (PI), polydimethylsiloxane (PDMS), polyetherimide (PEI), poly(2,6-dimethyl-1,4-phenylene oxide) (PPO), polyvinyl alcohol (PVA), polyacrylic acid (PAA), polyurethanes (PU), poly(1-trimethylsilyl-1-propyne) (PTMSP), polybenzimidazoles (PBI), polydicyclopentadienes (pDCPD), polyaryl ether ketones (PAEK) and mixtures of these materials.
11. The process according to claim 1 , wherein the separation-active layer is composed of a PAEK polymer.
12. The process according to claim 11 , wherein the separation-active layer is composed of PEEK.
13. The process according to claim 1 , wherein the reaction solution is from an alkoxycarbonylation reaction, and wherein, in the alkoxycarbonylation, a C2 to C20 hydrocarbon having at least one olefinic double bond is reacted with an alcohol and carbon monoxide in the presence of the homogeneous catalyst system.
14. The process according to claim 13 , wherein the alcohol used in the alkoxycarbonylation is a mono- or polyol (two or more OH groups) having 1 to 50 carbon atoms or a mixture of two or more mono- and/or polyols.
15. The process according to claim 1 , wherein the acid is a Brønsted acid having a pKa ≤3, or a Lewis acid selected from the group consisting of aluminium triflate, aluminium chloride, aluminium hydride, trimethylaluminium, tris(pentafluorophenyl)borane, boron trifluoride, boron trichloride, and mixtures thereof.
16. The process according to claim 1 , wherein the acid is said Lewis acid, and
wherein the Lewis acid is added in a molar ratio of Lewis acid to ligand of 1:1 to 20:1.
17. The process according to claim 12 , wherein the separation-active layer has a degree of sulfonation of less than 20%.
18. The process according to claim 1 , wherein the at least one metal is palladium.
19. The process according to claim 1 , wherein the acid is aluminium triflate.
20. The process according to claim 1 , wherein a base and a solvent are not added to the reaction solution.