Croconic acid or 4,5-dihydroxycyclopentenetrione is a chemical compound with formula C5H2O5 or (C=O)3(COH)2. It has a cyclopentene backbone with two hydroxyl groups adjacent to the double bond and three ketone groups on the remaining carbon atoms. It is sensitive to light, soluble in water and ethanol and forms yellow crystals that decompose at 212°C.

CAS：488-86-8
中文别名：克酮酸;4,5-二羟基-4-环戊烯-1,2,3-三酮;
英文别名：4,5-dihydroxycyclopent-4-ene-1,2,3-trione;4,5-Dihydroxy-4-Cyclopentene-1,2,3-Trione;Croconic Acid;4-Cyclopentene-1,2,3-trione, 4,5-dihydroxy-;
分子式：C5H2O5
分子量：142.066
精确质量：141.99
Psa：91.67
Logp：-0.9651

MDL号：MFCD00181389

外观与性状：金色粉末
密度：2.311g/cm3
沸点：291.7ºC at 760mmHg
熔点：>300ºC(lit.)
闪点：144.4ºC
折射率：1.619
稳定性：Stable. Incompatible with strong oxidizing agents.
蒸汽压：1.98E-06mmHg at 25°C

安全说明：37/39-26
危险类别码：R36/37/38
WGK Germany：3
海关编码：2916190090
危险品标志：Xi

生产方法
1.制法：于装有搅拌器、回流冷凝器（装氯化钙干燥管）的反应瓶中，加入新蒸馏过的乙醛