Study On Preparation Of C.I. Pigment Red177

PR177is an advanced organic pigment，which shows good weather, solvent andchemicals resistance. For the Outstanding properties including strong coloring,excellent migration resistance and high plastic mold temperature, PR177has been notonly the leading variety of red organic pigments for coloring of synthetic resins andplastics, but also widely used in the field of paints, inks, coatings, fibers, liquidcrystal and so on. Currently, by Ullmann condensation reaction and desulfonationreaction, the PR177was synthesized while bromamine acid was used as the rawmaterial. However, a lot of acid waste water are produced and results inenvironmental pollution shortcomings. In this paper, for the benefit of environmentand economy, we investigated the influence of solvents and activation of organicsolvents copper catalyst on the Ullmann condensation reaction, and the effect of ionicliquids and sulfuric acid base reaction media reaction to the desulfonation reaction.Also, the study on the method of pigmentation of PR177was conducted.1. Fresh copper powder directly reduced by NaH2PO2was adopted in theUllmann self-condensation reaction of bromamine acid by one-pot method. Theoptimal reaction conditions were as follows: the dosage of CuSO4ï¹'5H2O, EDTA andNaH2PO2ï¹'H2O was20.0g,5.8g and20.4g separately. The reduction reactiontemperature was70℃, the dosage of bromamine acid was5.0g, condensation reactiontemperature90℃, the condensation reaction time was3h, the yield of thecondensation product was97.9%.2. It is economical and environmental protection synthetic process that95%ethanol is used as reaction solvent for the synthesis of DAS. The optimal reactionconditions were as follows:10.0g bromamine acid and5.0g copper powder wereadded to300mL95%ethanol which was the reaction medium reduction. Reactiontemperature was78℃, the yield of the DAS was84.8%.3. The process that sulfuric acid is used as reaction solvent for the synthesis ofPR177was studied. The optimal reaction conditions were as follows: the dosage ofDAS and sulfuric acid was4.5g and45g separately. The quality fraction of sulfuricacid solution was85%, the reaction temperature was150℃, the reaction time was5h,the yield of PR177was95.0%. 4. The synthesis of PR177was the desulfonation of DAS in ionic liquids insteadof H2SO4. The influences of the acidity, dosage and recycle of ionic liquids, reactiontime, reaction temperature on the yield of PR177were studied. The acidity of ionicliquids satisfied the acidity requirement of desulfonation of the DAS. The recycle ofionic liquids was convenient, and it reduced the discharge of wastewater. Thesynthesis technology was environmentally friendly. The optimal reaction conditionswere as follows: the dosage of DAS and [BSMIm]OTF were2.0g and10g separately,the reaction temperature was150℃, the reaction time was5h, the number of recycleof ionic liquids was6, the yield of PR177was94.6%.5. In pigmentation of PR177, the comparison of different methods ofpigmentation was studied. The solvent treatment of the crude pigment is better thanthe others. The optimal reaction conditions were as follows: DMF was Selected as thesolvent of pigmentation, the dosage of DMF was5times than the crude pigment,thetime of pigmentation was0.5h, the temperature of pigmentation was100℃. Thecolors, coloration and transparency of PR177were similar to the standard sample.