Pigment Red 176 synthesis

Yield: 340 kg

Reaction Conditions:

Stage #1:3-amino-4-methoxybenzoic acid phenylamide with hydrogenchloride in water at 1; for 1 h;Large scale;
Stage #2: with sodium nitrite in waterLarge scale;
Stage #3:3-hydroxy-N-(2-oxo-2,3-dihydro-1H-1,3-benzodiazol-5-yl)naphthalene-2-carboxamideLarge scale;Further stages;

Steps:

1 Example 1
In the diazo pot by adding 1000 kg water and 160kg30% hydrochloric acid, is added under agitation giving cash 150kg3-amino-4-methoxy compositions, beating 1 hours, with ice-cooling to 0 °C the following, adjusting volume to 2500L, dissolved in advance of to 40% of the content of sodium nitrite (folding stem 42.5 kg sodium nitrite water 64 kg), measured end point keep the potassium iodide starch paper micro-blue, keeping temperature 5-10°C, stirring 30 minutes, add 20 kg of diatomaceous earth, stirring 20 minutes, filtered salt solution.A small quantity of water of added to the coupling pot, open stirring, will giving cash 186.5kg5 - (2 the [...] -hydroxy -3 the [...] -naphthalene carboxamide yl) - 2-benzimidazolone adding the colloid rubs into randoms pot, by adding 0.6 kg eighteen alkane mellow base polyoxyethylene ether, beating 0.5 hours, adjusting volume to 1500L, adjusting temperature is 0-10°C.The diazonium salt is slowly added to the pulping solution of 5 - (2 the [...] -hydroxy -3 the [...] -naphthalene carboxamide yl) - 2-benzimidazolone suspension coupling reaction in, at the same time, in the coupling process the mass concentration 20% of sodium bicarbonate solution dripped into randoms pan, maintain the reaction system pH value is 5.5-6.0, coupling component dropping time is 0.5-1 hours, randoms temperature 5-10°C, randoms end, re-stirring and a half hours, heating to 70-80°C, thermal insulation 1-2 hours, the invention aims to, rinse resulting pigment after the coarse filter.Added to the reaction kettle pyrrole winds the alkane alkone 2000L, adding the above-mentioned pigment crude, beating, raising the temperature to 100-110°C, thermal insulation 2 hours, specifically pigment conversion situation, cooling to 40-50°C, filtering, washing, 80 °C drying, crushing C.I is obtained. Pigment red 176 finished product. Number is about 340 kg.

References:

Shangyu Xinli Chemical Industry Co., Ltd;Chen, Jianxin;Ni, Yuebio;Zhang, Lixin;Fang, Biao CN105524484, 2016, A Location in patent:Paragraph 0025; 0026; 0027; 0028