Fine chemicals are an important group of products consisting of pharmaceuticals, agrochemicals, dyes, photographic chemicals and intermediates of all these groups as well as chemicals for the textile industry. They are typically high value-added products. The processes for manufacturing these products are mostly batch and semibatch processes. The development of kinetic models for complex chemical reactions occurring in the fine chemical processes and including these models into batch and semibatch reactor models for scale-up are presented in this paper. A methodological approach to the modelling of these complex systems and the estimation of model parameters is proposed. The methodologies were applied to two case studies: reductive N-alkylation of an aromatic amine with homogeneous reactions and a heterogeneously catalysed reactions and Claisen condensation as organic liquid-solid reaction.