Previous work stated that poly(glycerol sebacate) synthesis is most effective when substrates are in the stoichiometry of functional groups, according to polymerization theories. Despite that, these syntheses were quite long (24 hours or more) to obtain the polyester with conversion near the gelling point. To shorten reaction time PTSA (p-toluenesulfonic acid) was used as catalyst. The concentration was tested (Table ) and the concentration of 1‰ was determined as optimal. Above that concentration, the reaction was faster but less stable. It is crucial to drain the reactor before the reaction mixture starts gelling, which could be too hard with the use of bigger PTSA amounts. Also, only 1‰ of PTSA is enough to shorten the reaction time significantly. Transferring to a large scale and optimization Larger-scale transfer was performed to allow small amounts of the reaction mixture to be sampled without significantly affecting the process under study. The process was performed on a 10 times bigger scale than the preliminary study. In order to reduce costs, the process was immediately optimized using the RSM method. Due to the lack of data, it was not possible to plan experiments according to the Design of Experiments method. In this work, we present a non-standard approach that allowed for a significant reduction in the number of experiments performed compared to DoE. At the same time, the obtained mathematical model allowed for the precise determination of optimal parameters. The presented approach may prove valuable for the industry, especially on smaller research and development scales.