| abstract |
A process for producing an organic pigment represented by the general formula (I): A(H)x(CH3)y, characterized in that an organic pigment represented by the formula (II): A(H)x+y, is reacted with dimethylcarbonate in the presence of a base with or without a solvent, wherein in formulae (I and II) x + y is an integer 1 to 4 with x being 0 to 4 and y being 1 to 4, A is the residue of an organic pigment containing x + y cyclic or open -NH- groups, and the H as well as CH3 in formula (I and II) are bound to the above mentioned N. This process is suitable for the production of N-methylated organic pigments in an environmentally safe process and at a low production cost. |