Azo Pigment Synthesis by Continuous Operation

A number of publications describe continuous techniques used to manufacture azo colorants, especially azo pigments (selection see [6]). 

The widespread interest in continuous methods is readily explained by the expected advantages  

The following factors determine the outcome of azo pigment production by continuous process  

The first five of these parameters apply to all continuous azo-coupling reactions, while the last four pertain to azo pigments only. 

The overall process can be related to two operations diazotization and coupling. Out of the vast number of patents concerning continuous methods of azo pigment formation, the following examples have been chosen. 

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