Methylene diphenyl diisocyanate, most often abbreviated as MDI, is an aromatic diisocyanate. It exists in three isomers, 2,2'-MDI, 2,4'-MDI, and 4,4'-MDI, however, the 4,4' isomer is most widely used. This isomer is also known as Pure MDI. MDI reacts with polyols in the manufacture of polyurethane. It is the most produced diisocyanate, accounting for 61.3% of the global market in the year 2000.

CAS：101-68-8
中文别名：MDI;4,4\'-亚甲基双(异氰酸苯酯);二苯基甲烷-4,4\'-二异氰酸酯;二苯甲撑二异氰酸酯;
英文别名：Methylene di-p-phenyl diisocyanate,flakes;4,4\'-Diphenylmethane Diisocyanate;PMDI;4,4-Diphenylmethane Diisocyanate;desmodur44;4,4\'-diphenylmethanediisocyanate;Methylenediphenyl 4,4\'-Diisocyanate;bis(4-isocyanatophenyl)methane;4,4\'-methylenediphenyl diisocyanate;1,1‘-Methylenebis[4-isocyanatobenzene];caradate30;hylenem50;4,4\'-Diphenylmethane diisocyanate;methylene 4,4\'-diphenyl diisocyanate;4,4\'-MDI;Bis(4-isocyanatophenyl)methane;Isonate;p,p\'-diphenylmethane diisocyanate;methylene;4,4\'-Methylenebis(phenyl Isocyanate);
分子式：C15H10N2O2
分子量：250.252
精确质量：250.074
Psa：58.86
Logp：3.212

BRN号：797662
PubChem号：24860077
MDL号：MFCD00036131
RTECS号：NQ9350000
EINECS号：202-966-0

外观与性状：白色至淡黄色片或晶体
密度：1.19
沸点：392 °C
熔点：38-44 °C
凝固点：37℃
闪点：196 °C
折射率：1.5906 (50ºC)
水溶解性：decomposes
稳定性：Stable. Combustible. Incompatible with strong oxidizing agents. Reacts violently with alcohols.
储存条件：库房通风低温干燥,与含水物品、醇类、胺类分开储运
蒸汽压：9.02E-06mmHg at 25°C

RTECS号：NQ9350000
安全说明：S45-S36/37-S23
危险类别码：R20; R36/37/38; R42/43
海关编码：29291090
危险品运输编码：2206
危险类别：6.1
包装等级：II
危险品标志：Xn
危险标志：GHS07, GHS08
危险性描述：H315; H317; H319; H332; H334; H335; H351; H373
危险性防范说明：P260; P280; P284; P304 + P340; P305 + P351 + P338; P342 + P311
信号词：Danger

生产方法
1.(1)光气合成法 由苯胺和甲醛缩合制备二氨基二苯甲烷 用作聚氨酯泡沫塑料、橡胶、纤维、涂料等的原料。
用途
用作聚氨酯泡沫塑料、橡胶、纤维、涂料等的原料。