Introduction of carboxylic groups

Hyperbranched polymers of polybenzene type can be rendered water-soluble like the above-mentioned monodisperse species by introduction of carboxyl groups [62]. Starting from 3,5-dibromophenylboronic acid 1 as AB2 monomeric building block (Fig. 4.34), the polycondensate 2 was assembled in an aryl-aryl coupling analogous to Suzuki coupling in the presence of Pd(0), and subsequently reacted with carbon dioxide to form the hyperbranched compounds 3 with terminal carboxylate groups ... 

Carboxylation. The introduction of carboxyl groups into the structures of phenols and naph-thols produces some important dye intermediates, including salicylic acid and (3-oxynaphthoic acid (BON acid). This process is conducted under pressure at elevated temperatures using the sodium salts of phenols/naphthols and in the case of (3-naphthol, the carboxyl group enters... 

The reaction appears to be well suited for selective conversion of biomass carbohydrates into their corresponding oxidized derivatives. This system serves to oxidize several polymeric carbohydrates including starches and pullulan.445 49 More recent work has described the TEMPO-catalyzed introduction of carboxyl groups in native cellulose and its different morphological forms,45(M52 cellulose derivatives,453 and the surface of cellulose nanocrystals.454 The related biopolymer, chitin, also is oxidized under these conditions.455... 

Introduction of carboxyl groups (Kdbe-Schmidt synthesis)... 

The introduction of carboxyl groups in the surface of an adhesive increased (i) the peel strength Immediately after bonding and variation ratio with time, and (il) the peel strength at the wide range of rates, where the shape of the whole curve varied compared with the adhesive with hydroxyl groups. 

Introduction of carboxyl groups by copolymerization of ethylene and CO, the carbonyl ions absorb UV radiation and facilitate break-up of chains into smaller parts... 

While the two-step functionalization of CNTs through the oxidative introduction of carboxyl groups followed by the formation of amide or ester linkages does allow for a stable chemical modification, it has only a relatively weak effect on the electrical and mechanical properties of the CNTs. In comparison, addition reactions enable the direct coupling of functional groups onto the n-conjugated carbon framework of the CNTs. The required... 

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