Method for producing perylene-3,4-dicarboxylic acid imides

1. A process for preparing perylene-3,4-dicarboximides which bear a sterically demanding substituent on the imide nitrogen atom and have the general formula II

in which the variables are each defined as follows:

is C 3 -C 24 -alkyl which is branched in the 1-position and whose carbon chain may be interrupted by one or more —O—, —S—, —CO— and/or —SO 2 — moieties and which may be mono- or polysubstituted by carboxyl, sulfo, hydroxyl, cyano, C 1 -C 6 -alkoxy, C 3 -C 8 -cycloalkyl which may comprise from one to four heteroatoms in the ring system and/or C 6 -C 10 -aryl which may comprise from one to three heteroatoms in the ring system;

phenyl which is substituted in the ortho-position by at least one of the substituents (a) to (e) and may bear the same or one or more different substituents (a) to (e) in the further ring positions and which may comprise one or two heteroatoms in the ring:

(a) C 1 -C 24 -alkyl whose carbon chain may be interrupted by one or more —O—, —S—, —NR 4 —, —CO— and/or —SO 2 — moieties and which may be mono- or polysubstituted by carboxyl, sulfo, hydroxyl, cyano, halogen, nitro, C 1 -C 6 -alkoxy, C 3 -C 8 -cycloalkyl which may comprise from one to four heteroatoms in the ring system and/or C 6 -C 10 -aryl which may comprise from one to three heteroatoms in the ring system;

(b) C 1 -C 24 -alkoxy or C 1 -C 24 -alkylthio, each of which may be mono- or polysubstituted by C 1 -C 6 -alkyl and/or phenyl;

(c) C 3 -C 8 -cycloalkyl which may comprise from one to four heteroatoms in the ring system, may comprise unsaturated bonds and may be mono- or polysubstituted by carboxyl, sulfo, hydroxyl, cyano, halogen, nitro, C 1 -C 6 -alkoxy and/or C 6 -C 10 -aryl which may comprise from one to three heteroatoms in the ring system;

(d) C 6 -C 10 -aryl which may comprise from one to three heteroatoms in the ring system, to which further 5- to 7-membered, saturated, unsaturated or aromatic rings may be fused and which may be mono- or polysubstituted by C 1 -C 12 -alkyl;

(e) carboxyl, hydroxyl, cyano, halogen, nitro, —SO 7 NR 4 2 ;

1-naphthyl which is substituted in the ortho-position by one of the substituents (a) to (e) specified for phenyl and may bear in the further ring positions the same or one or more different substituents (a) to (e) and which may comprise from one to three heteroatoms in the ring system;

2-naphthyl which is substituted in both ortho-positions by one of the substituents (a) to (e) specified for phenyl or different substituents from this group and may bear in the further ring positions the same or one or more different substituents (a) to (e) and which may comprise from one to three heteroatoms in the ring system;

R′ are each independently hydrogen; halogen; C 1 -C 18 -alkyl; C 6 -C 10 -aryloxy or -arylthio, each of which may comprise from one to three heteroatoms in the ring system and each of which may be substituted by C 1 -C 10 -alkyl, C 1 -C 6 -alkoxy, cyano and/or carboxyl;

R 4 is hydrogen; C 1 -C 12 -alkyl,

by reacting a perylene-3,4:9,10-tetracarboxylic dianhydride of the general formula III

with a sterically hindered primary amine of the general formula IV

R—NH 2   IV

in a substantially anhydrous reaction medium, which comprises undertaking the reaction in the presence of a tertiary amine, of a solvent based on a cyclic imine or amide and of a Lewis acid as a catalyst.

2. The process according to claim 1 , wherein the tertiary amine used is an amine of the general formula I

in which the variables are each defined as follows:

R 1 , R 2 are each independently

hydrogen;

C 1 -C 23 -alkyl whose carbon chain may be interrupted by one or more —O—, —S— and/or —NR 4 — moieties and which may be substituted by hydroxyl, cyano, halogen, nitro, C 6 -C 10 -aryl which may comprise from one to three heteroatoms in the system and/or C 4 -C 12 -cycloalkyl which may comprise from one to four heteroatoms in the ring system;

C 4 -C 12 -cycloalkyl whose carbon ring may be interrupted by one or more —O—, —S— and/or —NR 4 — moieties and which may be substituted by C 1 -C 18 -alkyl, hydroxyl, cyano, halogen and/or nitro;

C 6 -C 10 -aryl which may be substituted by C 1 -C 18 -alkyl, hydroxyl, cyano, halogen and/or nitro;

together are a 4- to 9-membered saturated ring which comprises the —CH 2 —NR 3 —CH 2 — moiety and may be interrupted by further —O—, —S— and/or —NR 4 — moieties and may be substituted by C 1 -C 6 -alkyl, C 6 -C 10 -aryl, hydroxyl, cyano, halogen and/or nitro;

R 3 is C 4 -C 24 -alkyl, whose carbon chain may be interrupted by one or more —O—, —S— and/or —NR 4 — moieties and which may be substituted by hydroxyl, cyano, nitro, C 6 -C 10 -aryl which may comprise from one to three heteroatoms in the ring system and/or C 4 -C 12 -cycloalkyl which may comprise from one to four heteroatoms in the ring system;

C 4 -C 12 -cycloalkyl whose carbon ring may be interrupted by one or more —O—, —S— and/or —NR 4 — moieties and which may be substituted by C 1 -C 18 -alkyl, hydroxyl, cyano, halogen and/or nitro;

C 6 -C 10 -aryl which may comprise from one to three heteroatoms in the ring system and which may be substituted by C 1 -C 18 -alkyl, hydroxyl, cyano and/or nitro;

R 1 , R 2 and R 3 join together to form a saturated, bicyclic 8- to 12-membered ring system which comprises the

moiety and if appropriate further —O—, —S— and/or —NR 4 — moieties;

R 4 is hydrogen; C 1 -C 12 -alkyl.

3. The process according to claim 1 , wherein the tertiary amine used is an amine of the general formula I

in which the variables are each defined as follows:

R 1 , R 2 are each independently

hydrogen;

C 1 -C 11 -alkyl which may be substituted by hydroxyl;

together are a 4- to 9-membered saturated ring which comprises the —CH 2 —NR 3 —CH 2 — moiety and may be interrupted by further —NR 4 — moieties;

R 3 is C 4 -C 12 -alkyl which may be substituted by hydroxyl;

pyridyl;

R 1 , R 2 and R 3 join together to form a bicyclic 8-membered ring system which comprises the

moiety and one further nitrogen atom;

R 4 is hydrogen; C 1 -C 12 -alkyl.

4. The process according to claim 1 , wherein the tertiary amine used is an amine whose boiling point is above the reaction temperature.

5. The process according to claim 1 , wherein the cyclic imine used is a cyclic aromatic imine.

6. The process according to claim 1 , wherein the Lewis acid used is a transition metal catalyst based on iron, zinc, zinc salts, copper, copper salts or mixtures thereof.

7. The process according to claim 1 , wherein from 0.01 to 4 mol of tertiary amine are used per mole of perylene-3,4:9,10-tetracarboxylic dianhydride.

8. The process according to claim 1 , wherein the perylene-3,4-dicarboximides of the general formula II is prepared

in which the variables are each defined as follows:

R is C 3 -C 24 -alkyl which is branched in the 1-position;

phenyl which is substituted in both ortho-positions by secondary C 3 -C 12 -alkyl radicals or in one ortho-position by a tertiary C 4 -C 12 -alkyl radical and which may be substituted in the other positions by C 1 -C 12 -alkyl, C 6 -C 10 -aryl and/or halogen;

R′ is hydrogen; halogen; C 6 -C 10 -aryloxy or -arylthio, each of which may be substituted by C 1 -C 10 -alkyl, C 1 -C 6 -alkoxy, cyano and/or carboxyl.