•A mid-term production plan is obtained for a chemical company.•Mathematical programming is used to maximize the company's profit.•Non-constant consumption of materials based on produced quantity is considered.•The tool can be used for strategic planning, simulating different scenarios. Two particular features of a chemical problem with a production planning problem motivate the development of a novel ad-hoc mathematical model for the optimal solution: the consumption of raw materials may not be constant and depend on the quantity to be produce of one reference product, and the demand supplied should be embedded between a minimum (established by contract) and a maximum value. This work aims to plan the production of the company's semi-finished and final products to maximize the profits from the products sales considering resources costs. This mid-term plan is calculated with an optimization tool developed based on a mixed-integer linear programming model. Availability of resources and particular constraints around recipes and processes are considered. An optimal solution is achieved in short time, providing valuable information of the profits expected. Different scenarios are also simulated to study capacity expansions or alternative market positions.