N-Ethylmaleimide (NEM) is an organic compound that is derived from maleic acid. It contains the imide functional group, but more importantly it is an alkene that is reactive toward thiols and is commonly used to modify cysteine residues in proteins and peptides.

CAS：128-53-0
中文别名：N-乙基顺丁烯二酰亚胺;1-乙基-1H-吡咯-2,5-二酮;N-乙基顺丁烯二酰亚胺(NEM);N-乙基失水苹果酰亚胺;N-乙基;
英文别名：1-ethyl-1H-pyrrole-2,5-dione;1H-Pyrrole-2,5-dione, 1-ethyl-;n-ethyl-maleimid;1-ethylmaleimide;N-ethyl-maleimide;N-ethylmaleic imide;ethvlmaleimide;n-ethvlmaleimide;1-Ethyl-1H-pyrrole-2,5-dione;N-Ethylmaleinimid;N-EthylMaleiMide;Ethylmaleimide;N-Ethylmaleimide;
分子式：C6H7NO2
分子量：125.125
精确质量：125.048
Psa：37.38
Logp：-0.1308

MDL号：MFCD00005509
EINECS号：204-892-4
RTECS号：UX9625000
BRN号：112448
PubChem号：24278420

外观与性状：白色固体
密度：1.207 g/cm3
沸点：210°C(lit.)
熔点：43-46°C(lit.)
闪点：73 °C
折射率：1.514
水溶解性：1 g/L (20 ºC)
稳定性：Stable. Combustible. Incompatible with strong oxidizing agents. Refrigerate.
储存条件：2-8ºC
蒸汽压：0.197mmHg at 25°C

RTECS号：UX9625000
安全说明：S26-S28-S36/37/39-S45-S28A
危险类别码：R20/21; R28; R34; R43
WGK Germany：3
危险品运输编码：UN 2928 6.1/PG 2
海关编码：2925190090
危险类别：6.1
包装等级：II
危险品标志：T+
危险标志：GHS05, GHS06
危险性描述：H300; H311; H314; H317
危险性防范说明：P264; P280; P301 + P310; P305 + P351 + P338; P310
信号词：Danger