Chemicals impact the environment. However, life cycle assessments (LCA) of products containing chemicals are often not possible due to a lack of available datasets. Existing methodologies to address this problem have several shortcomings. Therefore, a new approach to model chemicals is introduced to fill dataset gaps in inventory databases. Further data for 60 chemicals are provided. The approach consists of four steps: (i) general research on the chemical and the synthesis processes, (ii) setting up the reaction equations, (iii) researching the required thermal energy, and (iv) modeling of the dataset (RREM). Depending on the obtained data, calculations are carried out or assumptions are applied. The environmental impact of the chemicals is modeled in the LCA software linking to existing datasets. A case study of the chemical octocrylene illustrates the application of RREM. An overview is given of the environmental profile of 60 chemicals modeled based on RREM. The validity of the assumptions and their influences on the results are examined by a sensitivity analysis. By modeling chemicals with the RREM approach, previously unknown environmental impacts of chemicals and products containing them can be determined