Carbon Dioxide → Solvent Red 49

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

The Rhodamine dye of formula (II), Rhodamine B free base (Colour Index 45170:1), a well-known pigment, can be prepared by heating a stirred mixture of 10 parts by weight of m-diethylaminophenol and 12 parts by weight of phthalic anhydride to 175° C. under a blanket of carbon dioxide. The reaction mixture is stirred at 170°-175° C. for a period of 6-7 hours, then cooled to 40° C. and discharged into water. The pH of the resulting slurry is adjusted to 12 by adding caustic soda, and the insoluble material is recovered by filtration. The filter cake is then rinsed with water and dried to obtain Rhodamine B Base in a yield about 90% of theoretical.

Herkunft & Nachweise