Water is commonly used as a blowing reagent in PU foam formulation, due to the generation of carbon dioxide during the reaction of isocyanate with water (Fig. 1a). Alternatively, carboxylic...

The reactions between substituted isocyanates (RNCO) and other small molecules (e.g. water, alcohols, and amines) are of significant industrial importance, particularly for the development of novel polyurethanes and other useful polymers.

In the presence of water the isocyanate reacts with water. This leads to formation of carbon dioxide and gassing or foaming. The amine formed reacts very fast with the isocyanate forming an urea linkage.

Isocyanate reacts with water giving carbamic acid, an unstable compound which spontaneously decomposes into a primary amine and carbon dioxide, together with a subsequent urea formation (Fig. 4). [Pg.104]

In aqueous solution the isocyanate reacts with water to give a carbaminic acid 6, which immediately decarboxylates to yield an amine 3. When alcohol is used as solvent, the isocyanate reacts to a carbamate 7 ... [Pg.72]

Isocyanates react with water to produce carbon dioxide and an amine. In this reaction, the isocyanate group (-NCO) reacts with water, resulting in the formation of an amine group (-NH2) and the release of carbon dioxide (CO2).

The Curtius Rearrangement is the thermal decomposition of carboxylic azides to produce an isocyanate. These intermediates may be isolated, or their corresponding reaction or hydrolysis products may be obtained. The reaction sequence - including subsequent reaction with water which leads to amines - is named the Curtius Reaction.

The reactions between substituted isocyanates (RNCO) and other small molecules (e.g. water, alcohols, and amines) are of signi cant industrial importance, particularly for the development of novel polyurethanes and other useful polymers.

Isocyanates react with compounds, which give a positive Zerewitinoff test. These include alcohols, water, phenols, amino groups (primary and secondary), carboxylic acids, and certain compounds having activated methylene groups, such as acetoacetic ester, and malonic ester.

2023年6月7日 · Water reacts with isocyantes to give a carbamic acid. This reaction is catalyzed by tertiary amines. Carbamic acids are unstable and decompose to carbon dioxide and an amine, R-NH2. Alcohols react with isocyanates to give carbamates which are also known as urethanes.