Isocyanaattiryhmät

Isocyanaattiryhmät are organic compounds characterized by the presence of a functional group with the general formula R−N=C=O. This group is highly reactive due to the cumulative double bonds between nitrogen, carbon, and oxygen atoms. The carbon atom in the isocyanate group is electrophilic, making it susceptible to attack by nucleophiles.

The most common isocyanate is toluene diisocyanate (TDI), used extensively in the production of polyurethane foams and elastomers. Methylene diphenyl diisocyanate (MDI) is another significant industrial isocyanate, also a key component in polyurethane manufacturing, particularly for rigid foams and coatings. Other isocyanates, such as hexamethylene diisocyanate (HDI), are used in applications requiring good weatherability and flexibility.

Isocyanates are important intermediates in organic synthesis and are crucial for the production of a vast array of polymeric materials. Their reactivity allows them to readily react with compounds containing active hydrogen atoms, such as alcohols and amines, to form urethanes and ureas, respectively. This reaction forms the basis of polyurethane chemistry. However, isocyanates are also known for their toxicity, particularly as respiratory sensitizers, and appropriate safety precautions are necessary when handling them.