Various carbamates can be prepared in a halogen-free way starting from cheap and readily available reagents such as amines, alcohols and carbon dioxide. Basic catalysts were able to convert both linear and branched aliphatic amines to the corresponding carbamates with good yields, in mild reaction conditions (2.5 MPa CO2) and even in the absence of dehydrating agents.
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Ion et al. (2007) studied this question.
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