Robuta

https://jbpr.in/index.php/jbpr/article/view/1275/1095 View of A Review on Synthesis of new Azo Compounds of Para Hydroxy Benzaldehyde and Determination... https://pubchem.ncbi.nlm.nih.gov/patent/EP-0316722-A3 Water soluble azo compounds, process for their preparation and their use as dyestuffs - Patent... EP-0316722-A3 chemical patent summary.