Alizarine Yellow R is a yellow colored azo dye made by the diazo coupling reaction. It usually comes as a sodium salt. In its pure form it is a rust-colored solid. Its main use is as a pH indicator.

CAS：2243-76-7
中文别名：3-硝茜素;5-(4-硝基苯基偶氮)水杨酸;媒染橙 1;茜素黄 R;茜素R;媒介橙 1;对硝基苯偶氮水杨酸钠;茜素橙;
英文别名：Alizarine Yellow R;Alizarol Orange R;Alizarin Yellow R;5-(4-Nitrophenylazo)salicylic acid Alizarin Yellow R MO1;Benzoic acid, 2-hydroxy-5-[(4-nitrophenyl)azo]-;5-[(E)-2-(4-nitrophenyl)-1-diazenyl]-2-hydroxybenzoic acid;5-(4-Nitrophenylazo)salicylic Acid;Mordant Orange 1;Kenachrome Orange;mordant orange 1;Pnbas;Chrome Orange MR;Terracotta 2RN;Alizarin yellow R;Terra Cotta RRN;Chrome Orange R;Chrome Orange N;Magracrom Orange;5-(4-nitrophenylazo) salicylic acid;
分子式：C13H9N3O5
分子量：287.228
精确质量：287.054
Psa：128.07
Logp：3.9372

PubChem号：24851672
BRN号：962365
MDL号：MFCD00007313
RTECS号：VO5310000
EINECS号：218-818-3

外观与性状：红色-棕色结晶粉末
密度：1.49 g/cm3
沸点：500.2ºC at 760 mmHg
熔点：250°C
闪点：256.3ºC
折射率：1.671
水溶解性：SOLUBLE
稳定性：Stable under normal temperatures and pressures.
储存条件：Store in a tightly closed container. Store in a cool, dry, well-ventilated area away from incompatible substances.
蒸汽压：6.74E-14mmHg at 25°C

RTECS号：VO5310000
安全说明：S24/25-S26
危险类别码：R22
海关编码：2901100000
危险品标志：Xn

生产方法
1.将对硝基苯胺加入水中,加入盐酸,加热溶解,将亚硝酸钠溶液分次加入,经过滤,加入水杨酸钠,加热至沸,冷却、过滤即为粗品。粗品经处理即为纯品茜素黄R钠盐. 1.用作酸碱指示剂,ph值10.0(黄色)～12.0(红色)。
用途
1.用作酸碱指示剂,ph值10.0(黄色)～12.0(红色)。