Practical Applications of Mannich Bases

More recently, some review artieles have appeared in which several applications of Mannich bases in the pharmaceutical field - and in other industries,such as those connected with maeromolccular chemistry, arc described. However, no general, complete overview of the widespread practical applications of Mannich bases has been published so far, despite their connections with important branches of industrial organic chemistry. Although the most relevant contribution of the Mannich reaction is still in pharmaceutical research (over 30% of the scientific papers published on this subject are found in journals dealing with pharmaceutical chemistry), Mannich bases have been found to have important uses in the manufacture of polymeric materials (resins and, in particular, surface coatings) and in the production of various additives and auxiliaries (for lubricants, textiles, paper, etc.) as well as, for example, in the production of water-treatment agents. 

The Mannich reaction as well as Mannich bases are frequently involved in the production of crosslinked materials having important applications in industry as resins, coatings, adhesives, etc., as described below in the appnipriatc chapters on the practical use of Mannich bases. In addition to the inherent complexity of the matter, as far as chemistry and structure of products are concerned, it is necessary to bear in mind that the literature report.s, mainly patents, may be rather vague about the chcmistiy involved in the preparation of the final materials. 

The aim of the present book is therefore to describe and discuss the developments that have occurred in the last 30 years in the chemistry of Mannich bases, the preceding period being excellently covered by Blicke s overview and by the books of Hellmann and Opitz and Reichert (a scholar of Mannich). The wide range of practical applications made possible by using the chemistry of Mannich bases is also treated here. 

Hence, this versatility of the Mannich reaction, along with the remarkable possibilities of exploiting the reactivity of Mannich bases in producing further derivatives (Chap. 11), makes it possible to readily attain the most varied chemical structures in conformity with the practical requirements and applications needed in industry (Chap. V). 

As far as the shape and size of the molecules are concerned, direct Mannich synthesis or typical reactions of Mannich bases, such as amino group replacement, open up the possibility of producing derivatives that have the chemical structures 1-VII (Fig. 182). Examples of such derivatives are compounds 494—503, all selected from products that have properties with useful practical applications. Thus, nonsymmetrical molecules with different A and B functionalities (type I in Fig. 182), along with symmetrically disubstituted molecules (type II), cyclic or branched compounds (types III and IV), as well as polymeric or crosslinked derivatives (types V-VII), can be produced as the result of appropriate combinations of mono- or polyfunctional A and B reactants. 

Due to the presence of the same moieties as in low-molecular-weight Mannich bases, some polymeric substances prepared by Mannich synthesis or by functionali/.ation exhibit analogous chemical reactivity, thus making it pos.sible to carry out modihcalions of their properties in order to improve their practical application. In particular, ionic character, stability to degradation, etc., of the polymer may thus be affected. 

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