## 3 MIPs' Applications
### MIPs in Catalysis  
Considerable efforts have been made to investigate the possible use of MIP for catalytic applications [25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72]. The high selectivity and strength of these polymers make them suitable to be used at elevated temperatures and pressures, in the presence of several organic solvents, and also under acidic and basic reaction conditions. For these reasons, MIPs can be employed instead of biomolecules, such as enzymes and natural catalytic antibodies [166] which are highly vulnerable to certain conditions. The use of MIP for catalytic application is very important because MIP catalysts are able to mimic the selectivity and stereospecificity of the binding domains of antibodies and enzymes which are generally utilized as catalysts in several reactions. Catalytically active imprinted materials can be obtained using analogues of substrates, transition states or products as templates in the imprinting protocol [29]. The polymer matrix obtained has cavities with a shape similar to the shape of the template used [72, 167]; but the imprinting technology must also ensure the right placement of the functional groups in the binding sites in consideration of the type of catalytic process that they will assist [168]. The strategy using substrate analogues as template, involves the use of compounds that mimic the reaction complex between the substrate and the matrix. The catalytic groups will be introduced in the right positions into the cavities of the polymer and subsequently they will act catalytically in presence of the true substrate. [PERSON] and [PERSON] applied this strategy to obtain an imprinted matrix with esterolytic activity using Cobalt (II) ions to coordinate vinylimidazole groups and template during polymerization. Subsequent introduction of the substrates, such as p-nitrophenyl esters of methionine or leucine, into the cavities of polymer, leads to an acceleration and substrate-specific hydrolysis of amino acid analogues [169]. The same strategy was applied by [PERSON] and [PERSON] to obtain a dehydrofluorination of \(\beta\)-fluorketones using \(N\)-(2-aminoethyl)mathacrylamide as basic functional monomer with catalytic groups (Figure 8). Several dicarboxylic acids were employed as template analogues to obtain the correct positioning of the amino groups in the cavities of the polymer. It has been seen that the catalytic activity of the polymer mainly depends on the position of carboxylic groups of the template. Benzylmalonic acid has proven to be the best template to obtain the most active imprinted polymer [170]. An alternative approach to obtain the same results was the use, in the polymerization process, of a basic Transitional State Analogue (TSA) and MAA respectively as basic template and acidic functional monomers. The use of the MIP catalyst in the reaction process led to an increase in dehydrofluorination rate compared with the uncatalyzed reaction. The TSA approach was followed by [PERSON] and co-worker to obtain a phosphonate ester imprinted polymer using amidines as monomers. The amidines have the ability to bind carboxylic acids and phosphonate esters with very high affinity, such that the complexes are almost completely in the associated form, even in water. The catalyst was tested on the hydrolysis reaction of analogous carboxylate esters. High catalytic activity was seen, despite the nonactivated nature of the esters. The reaction rate was 100 times higher for the imprinted matrices compared with the uncatalysed solution reaction [171]. Very recently, [PERSON] _et al._[172, 173] prepared smart imprinting systems with catalytic activity. A catalytic and positively thermoresponsive MIP was prepared for the first time and used for catalytic hydrolysis of 4-nitrophenyl acetate, used as model reaction.