Amine carbon dioxide

A simpler nonphosgene process for the manufacture of isocyanates consists of the reaction of amines with carbon dioxide in the presence of an aprotic organic solvent and a nitrogeneous base. The corresponding ammonium carbamate is treated with a dehydrating agent. This concept has been apphed to the synthesis of aromatic and aUphatic isocyanates. The process rehes on the facile formation of amine—carbon dioxide salts using acid haUdes such as phosphoryl chloride [10025-87-3] and thionyl chloride [7719-09-7] (30). 

When a carbonyl group is bonded to a substituent group that can potentially depart as a Lewis base, addition of a nucleophile to the carbonyl carbon leads to elimination and the regeneration of a carbon-oxygen double bond. Esters undergo hydrolysis with alkali hydroxides to form alkali metal salts of carboxylic acids and alcohols. Amides undergo hydrolysis with mineral acids to form carboxylic acids and amine salts. Carbamates undergo alkaline hydrolysis to form amines, carbon dioxide, and alcohols. 

Keywords Silane coupling agents alkylammonium carbamates aminosilane-carbon dioxide salts amine-carbon dioxide salts. 

Many investigations of the molecular structure of thin films formed by y-APS deposited onto inorganic substrates from aqueous solutions have been carried out. Ondrus and Boerio [2] used reflection-absorption infrared spectroscopy (RAIR) to determine the structure of y-APS films deposited on iron, 1100 aluminum, 2024 aluminum, and copper substrates from aqueous solutions at pH 10.4. They found that the as-formed films absorbed carbon dioxide and water vapor to form amine bicarbonate salts which were characterized by absorption bands near 1330, 1470, 1570, and 1640 cm-1. y-APS films had to be heated to temperatures above about 90°C in order to dissociate the bicarbonates, presumably to free amine, carbon dioxide, and water. Since the amine bicarbonates failed to react with epoxies, the strength of adhesive joints prepared... 

Carbamate complexes are synthesized by carbonation of metal dialkylamides (equation 20), or by reaction of the appropriate amine, carbon dioxide, and a metal halide (equation 21). In both cases, it has been suggested that the reaction involves combination of the amine and carbon dioxide to form the carbamate anion, followed by anion exchange. ... 

The microbial degradation of 3-aryl-l,l-dimethylurea herbicides proceeds by stepwise demethylation into 3-aryl ureas, which are then decomposed into aryl amines, carbon dioxide and ammonia according to the following scheme ... 

CHLORODIETHYLALUMINUM (96-10-6) Pyrophoric liquid ignites spontaneously in air. reacts with air, forming hydrogen chloride and aluminum oxide fumes. Reacts violently with water. A strong reducing agent. Reacts, possibly violently, with oxidizers, alcohols, acids, amines, carbon dioxide, chlorine azide (explosive compound formed), phenols, cresols, nitrogen oxides, sulfur oxides. 

In general, the vapor pressure of carbamates is low, but some may sublimate slowly at room temperature, and this would appear to explain their loss from soil surfaces. As the distribution in air is considered to be minor, the aquatic media is an important transport route for the very soluble carbamates. In this case, the hazard is limited by thefr rapid decomposition under aqueous conditions. Carbamates are hydrolyzed spontaneously yielding, as final products, an amine, carbon dioxide, and an alcohol or phenol ... 

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