The goal of this project is the coupling between a chemical network including about 2500 reactions between 200 species and the 1+1 D model for a protoplanetary accretion disk. We will concentrate on the influence of reaction rates and stellar/disk parameters (stellar luminosity, accretion rates) on the results of the modeling. The project includes the development of an ionization model for protoplanetary accretion disks and numerical tools to test the sensitivity of the results to different reaction rates.