Ionic liquids for solubilizing polymers

Abstract

The present invention relates to a liquid composition which comprises at least one polymer and at least one ionic liquid, the cations of which are derived from polycyclic amidine bases, and a process for isolating cellulose from cellulose-containing sources using at least one such ionic liquid.

1 . A liquid composition comprising at least one ionic liquid represented by formula I 
       
         
           
           
               
               
           
         
         wherein 
         A together with the C—N group to which it is bonded, forms a 4- to 8-membered, saturated or unsaturated or aromatic ring, which is optionally substituted and/or which can optionally contain further heteroatoms or heteroatom-containing groups and/or which can include further fused-on saturated, unsaturated or aromatic carbocyclic rings or heterocyclic rings, 
         B together with the amidino group to which it is bonded, forms a 4- to 8-membered, mono- or polyunsaturated, non-aromatic ring, which is optionally substituted and can include further fused-on saturated, unsaturated or aromatic carbocyclic rings or heterocyclic rings, 
         R represents hydrogen or an organyl radical, 
         Y n-  represents a mono-, di-, tri- or tetravalent anion, and 
         n represents one, two, three or four 
         and at least one polymer solubilized therein. 
       
     
     
         2 . The liquid composition according to  claim 1 , wherein in the compounds of the formula I the cations are chosen from cations of the formulae I.1 and I.2 
       
         
           
           
               
               
           
         
         wherein 
         R and A are defined according to  claim 1 , and 
         R 1 , R 2 , R 3 , R 4 , R 5  and R 6  independently of one another represent hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, polycyclyl, heterocycloalkyl, aryl, hetaryl, hydroxyl, SH, polyalkylene oxide, polyalkyleneimine, alkoxy, alkylthio, alkylsulfinyl, alkylsulfonyl, halogen, SO 3 H, sulfonate, NE 1 E 2 , nitro, alkoxycarbonyl, COOH, carboxylate, formyl, acyl or cyano, wherein E 1  and E 2  denote in each case identical or different radicals selected from the group consisting of hydrogen, alkyl, cycloalkyl and aryl,
 wherein the radicals R 1 , R 2 , R 3 , R 4 , R 5  and R 6  which represent alkyl radicals can comprise 1, 2, 3, 4 or 5 substituents chosen from cycloalkyl, heterocycloalkyl, aryl, hetaryl, cycloalkoxy, cycloalkylthio, heterocycloalkoxy, heterocycloalkylthio, aryloxy, arylthio, hetaryloxy, hetarylthio, hydroxyl, SH, COOH, carboxylate, SO 3 H, sulfonate, NE 4 E 5 , (NE 4 E 5 E 6 ) + X − , halogen, nitro, formyl, acyl and cyano, wherein E 4 , E 5  and E 6  denote in each case identical or different radicals selected from the group consisting of hydrogen, alkyl, cycloalkyl and aryl, and X −  represents an anion equivalent, 
 and wherein the radicals R 1 , R 2 , R 3 , R 4 , R 5  and R 6  which represent cycloalkyl, cycloalkenyl, polycyclyl, heterocycloalkyl, aryl and hetaryl radicals can contain 1, 2, 3, 4 or 5 substituents which are chosen from alkyl and the substituents mentioned above for the alkyl radicals R 1  to R 6 , or 
 
         R 1  and R 3  and/or, if present, R 4  and R 6 , together with the ring carbons to which they are bonded, represent a 5- to 8-membered saturated, unsaturated or aromatic carbo- or heterocyclic radical, which is optionally additionally fused with one, two or three cycloalkyl, heterocycloalkyl, aryl or hetaryl, wherein the carbo- or heterocyclic radical and, if present, the fused-on groups independently of one another can each carry one, two, three or four substituents which are chosen from alkyl, cycloalkyl, heterocycloalkyl, aryl, hetaryl, hydroxyl, SH, halogen, COOH, carboxylate, SO 3 H, sulfonate, NE 7 E 8 , (NE 7 E 8 E 9 ) + X − , nitro, alkoxycarbonyl, formyl, acyl and cyano, wherein E 1 , E 8  and E 9  denote in each case identical or different radicals chosen from hydrogen, alkyl, cycloalkyl and aryl and X −  represents an anion equivalent,
 wherein in the compounds of the formula I.1, R 1  and R 3  or R 3  and R 5  also together can represent the bond portion of a double bond between the ring atoms which carry these radicals. 
 
       
     
     
         3 . The liquid composition according to  claim 1 , wherein A, together with the C—N group to which it is bonded, represents a 5- to 8-membered ring which is optionally additionally fused with one, two or three cycloalkyl, cycloalkenyl, heterocycloalkyl, aryl or hetaryl, wherein the heterocyclic radical and, if present, the fused-on groups independently of one another can each carry one, two, three or four substituents which are chosen from alkyl, alkenyl, cycloalkyl, cycloalkenyl, heterocycloalkyl, aryl, hetaryl, hydroxyl, SH, polyalkylene oxide, polyalkyleneimine, alkoxy, halogen, COOH, carboxylate, SO 3 H, sulfonate, NE 10 E 11 , (NE 10 E 11 E 12 ) + X − , nitro, alkoxycarbonyl, formyl, acyl and cyano, wherein E 10 , E 11  and E 12  denote in each case identical or different radicals chosen from hydrogen, alkyl, cycloalkyl and aryl and X −  represents an anion equivalent. 
     
     
         4 . The liquid composition according to  claim 1 , wherein in the compounds of the formula I the cations are selected from the group consisting of cations of 1,5-diazabicyclo[4.3.0]non-5-ene and 1,8-diazabicyclo[5.4.0]undec-7-ene. 
     
     
         5 . The liquid composition according to  claim 1 , wherein the polymer component comprises at least one biopolymer. 
     
     
         6 . The liquid composition according to  claim 5 , wherein the polymer component is chosen from polysaccharides and modified polysaccharides. 
     
     
         7 . The liquid composition according to  claim 6 , wherein the polymer component is cellulose. 
     
     
         8 . The liquid composition according to  claim 1 , wherein the polymer component comprises at least one synthetic polymer. 
     
     
         9 . The liquid composition according to  claim 8 , wherein the polymer component is selected from the group consisting of a polyurethane, a polyurea, a polyamide, a polysulfone, a polyether sulfone, a homopolymer of a cyclic ether, a copolymer of a cyclic ether and mixtures thereof. 
     
     
         10 . The liquid composition according to  claim 1 , wherein the polymer component comprises cellulose and at least one synthetic polymer selected from the group consisting of a polyurethane, a polyurea, a polyamide, a polysulfone, a polyether sulfone, a homopolymer of a cyclic ether, a copolymer of a cyclic ether, and mixtures thereof. 
     
     
         11 . A liquid composition obtained by a process comprising treating at least one lignocellulose material with at least one ionic liquid of the general formula I as defined in  claim 1 . 
     
     
         12 . A process for obtaining a base of the formula I.a 
       
         
           
           
               
               
           
         
         from a liquid treatment medium which comprises at least one ionic liquid of the general formula I 
       
       
         
           
           
               
               
           
         
         wherein the groups A and B are as defined according to  claim 1  and R represents hydrogen, in which a solution of a suitable base (Bs) in a solvent (S1) comprising water and/or at least one water-miscible solvent is added to the liquid medium and a phase separation is induced to give a phase enriched in the base of the formula I.a. 
       
     
     
         13 . The process according to  claim 12 , wherein the base (Bs) is chosen from alkali metal and alkaline earth metal hydroxides. 
     
     
         14 . The process according to  claim 12 , wherein the base (Bs) is employed in an amount of at least 2 molar equivalents based on the ionic liquid of the formula (I). 
     
     
         15 . The process according to  claim 12 , wherein the solvent (S1) is an aqueous solvent. 
     
     
         16 . The process according to  claim 12 , wherein an organic solvent (S2) which is chosen from aromatics, halogenated solvents, aliphatic solvents, ethers and mixtures thereof is added to the liquid treatment medium. 
     
     
         17 . The process according to  claim 12 , wherein methyl tert-butyl ether is employed as the solvent (S2). 
     
     
         18 . A compound of the formula I.2a and their salts I.2b 
       
         
           
           
               
               
           
         
         wherein 
         A together with the C—N group to which it is bonded, forms a 4- to 8-membered, saturated or unsaturated or aromatic ring, which is optionally substituted and/or which can optionally contain further heteroatoms or heteroatom-containing groups and/or which can include further fused-on saturated, unsaturated or aromatic carbocyclic rings or heterocyclic rings, 
         R represents hydrogen or an organyl radical, 
         R 1 , R 2 , R 3  and R 4  independently of one another represent hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, polycyclyl, heterocycloalkyl, aryl, hetaryl, hydroxyl, SH, polyalkylene oxide, polyalkyleneimine, alkoxy, alkylthio, alkylsulfinyl, alkylsulfonyl, halogen, SO 3 H, sulfonate, NE 1 E 2 , nitro, alkoxycarbonyl, COOH, carboxylate, formyl, acyl or cyano, wherein E 1  and E 2  denote in each case identical or different radicals chosen from hydrogen, alkyl, cycloalkyl and aryl,
 wherein the radicals R 1 , R 2 , R 3  and R 4  which represent alkyl radicals can contain 1, 2, 3, 4 or 5 substituents chosen from cycloalkyl, heterocycloalkyl, aryl, hetaryl, cycloalkoxy, cycloalkylthio, heterocycloalkoxy, heterocycloalkylthio, aryloxy, arylthio, hetaryloxy, hetarylthio, hydroxyl, SH, COOH, carboxylate, SO 3 H, sulfonate, NE 4 E 5 , (NE 4 E 5 E 6 ) + X − , halogen, nitro, formyl, acyl and cyano, wherein E 4 , E 5  and E 6  denote in each case identical or different radicals chosen from hydrogen, alkyl, cycloalkyl and aryl and X −  represents an anion equivalent, 
 and wherein the radicals R 1 , R 2 , R 3  and R 4  which represent cycloalkyl, cycloalkenyl, polycyclyl, heterocycloalkyl, aryl and hetaryl radicals can contain 1, 2, 3, 4 or 5 substituents which are chosen from alkyl and the substituents mentioned above for the alkyl radicals R 1  to R 6 , or 
 
         R 1  and R 3  together with the ring carbons to which they are bonded, represent a 5- to 8-membered saturated, unsaturated or aromatic carbo- or heterocyclic radical, which is optionally additionally fused with one, two or three cycloalkyl, heterocycloalkyl, aryl or hetaryl, wherein the carbo- or heterocyclic radical and, if present, the fused-on groups independently of one another can each carry one, two, three or four substituents which are chosen from alkyl, cycloalkyl, heterocycloalkyl, aryl, hetaryl, hydroxyl, SH, halogen, COOH, carboxylate, SO 3 H, sulfonate, NE 7 E 8 , (NE 7 E 8 E 9 ) + X − , nitro, alkoxycarbonyl, formyl, acyl and cyano, wherein E 7 , E 8  and E 9  denote in each case identical or different radicals chosen from hydrogen, alkyl, cycloalkyl and aryl and X −  represents an anion equivalent,
 wherein in the compounds of the formula I.1, R 1  and R 3  or R 3  and R 5  also together can represent the bond portion of a double bond between the ring atoms which carry these radicals, 
 
         Y n-  represents a mono-, di-, tri- or tetravalent anion, and 
         n represents one, two, three or four. 
       
     
     
         19 . A process for preparing a compound of the formula I 
       
         
           
           
               
               
           
         
         wherein 
         A together with the C—N group to which it is bonded, forms a 4- to 8-membered, saturated or unsaturated or aromatic ring, which is optionally substituted and/or which can optionally contain further heteroatoms or heteroatom-containing groups and/or which can include further fused-on saturated, unsaturated or aromatic carbocyclic rings or heterocyclic rings, 
         B together with the amidino group to the nitrogen atoms of which it is bonded, forms a 4- to 8-membered, mono- or polyunsaturated, non-aromatic ring, which is optionally substituted and can include further fused-on saturated, unsaturated or aromatic carbocyclic rings or heterocyclic rings, 
         R represents hydrogen, 
         Y n-  represents a mono-, di-, tri- or tetravalent anion, and 
         n represents one, two, three or four, 
         wherein a compound of the formula I.A 
       
       
         
           
           
               
               
           
         
         is reacted with an ammonium salt of the formula (NH 4 ) n Y.