Process of semicontinuously producing aniline condensed dyes

In a process for the production of aniline condensed dyes comprising the reacting, by heating, of the raw materials aniline and at least one of nitrobenzene, an alkylaniline, an alkylnitrobenzene or diazoaminobenzene in the presence of a catalyst wherein the heating is in a reaction system comprising reaction vessels susceptible to heat shock, the improvement which comprises:

• i. dividing said reaction system into at least three reaction sections, each section comprising one or more reaction vessels, the second section being maintained at a higher temperature than the first section and the third reaction section being maintained at a higher temperature than the second section;
• and
• ii. reacting said raw materials by successively and semicontinuously introducing batches of raw materials into said first reaction section, introducing the product therefrom into the second reaction section and introducing the product therefrom into the third reaction section without down times in the reaction vessels prior to said introduction.

In a process for the production of aniline condensed dyes comprising the reacting, by heating, of the raw materials aniline and at least one of nitrobenzene, an alkylaniline, an alkylnitrobenzene or diazoaminobenzene in the presence of a catalyst wherein the heating is in a reaction system susceptible to heat shock, the improvement which comprises:

• i. dividing said reaction system into two reaction sections, the number of reaction vessels in each section being in approximately direct proportion to the required reaction time in each section, each vessel having approximately the same capacity, wherein the second reaction section is maintained at a higher temperature than the first section and wherein each vessel in a section is maintained at substantially the same temperature;
• and
• ii. reacting said raw materials by successively and semicontinuously introducing batches of raw materials into said first reaction section and therefrom into an available vessel in said second reaction section without down times in the reaction vessels prior to said introductions.

In a process for the production of aniline condensed dyes comprising the reaction, by heating, of the raw materials aniline and at least one of nitrobenzene, and alkylaniline, an alkylnitrobenzene or diazoaminobenzene in the presence of a catalyst wherein the heating is in a reaction system susceptible to heat shock, the improvement which comprises:

• i. dividing said reaction system into three sections, the number of reaction vessels in each section being in approximately direct proportion to the required reaction time in each section, each vessel having approximately the same capacity, wherein the second reaction section is maintained at a higher temperature than the first section and the third reaction section is maintained at a higher temperature than the second section and wherein each vessel in a section is maintained at substantially the same temperature;
• and
• ii. reacting said raw materials by successively and semicontinuously introducing batches of raw materials into said first reaction section, therefrom into an available vessel in said second reaction section and therefrom into an available vessel in said third reaction section without down times in the reaction vessels prior to said introductions.