Study of Esterification Reactions in a Batch Reactor: Modeling the Industrial Synthesis of Benzoic Acid and Biodiesel

This experiment examines two esterification reactions: the de-esterification of ethyl benzoate into benzoic acid and the transesterification of palm oil into biodiesel. Through the de-esterification of ethyl benzoate, we mimicked the processes and experimental designs that are involved in the production of API’s (active pharmaceutical ingredients). The transesterification of palm oil allowed us to observe the production of biodiesel on a small scale. In a 1L batch reactor at 40C and 0.25 ethanol mole fraction, the rate constant was experimentally found to be 0.47 Ms. This value is important in that it tells us the rate (speed) of the reaction under the given conditions and compares favorably with the literature value of 0.51 Ms [2]. For the biodiesel reaction, we successfully produced biodiesel in a 1L batch reactor with a percent yield of 23% at 60C. Introduction The demand for pharmaceuticals is increasing; consequently, the need for efficient production designs is vital to the success of the pharmaceutical industry. By studying the synthesis of APIs, chemical engineers are striving to discover new ways to optimize the efficiency of these valuable reactions. Although API synthesis covers a multitude of chemical reaction types, our research focused on one specific reaction type: esterification. As with pharmaceuticals, the petroleum industry is constantly searching for new ways to increase their productivity. Additionally, these companies are actively pursuing viable and renewable alternative energy sources as a result of the decreasing fossil fuel reserves, which include wind power, solar power, and the focus of our second experiment: biodiesel. Esterification reactions involve either adding (transesterification) or removing (de-esterification) an ester group to/from a molecule. Esters are a type of molecule formed from an organic acid and an alcohol and have the general structure of R-CO-OR’. Ester molecules exist in a variety of forms, ranging from naturally occurring esters such as vegetable oils to commercially prepared products such as biodiesel. Commercially, esters are very prevalent and a valuable resource to many industries, especially the pharmaceutical industry. Many APIs, or active pharmaceutical ingredients, are formed in esterification reactions (ex. Aspirin). Without these quintessential ingredients, the medical and pharmaceutical industry would not be where it is today. Furthermore, it is of great importance to continue to study and understand how these esterification reactions work so engineers and other professionals can continue to produce products that will further benefit mankind. Commercially, these reactions take place in very large batch reactors. These specially designed vessels are often tailored to the reaction taking place, and provide a closed system that can often easily be controlled by a computer. These reactors also have the ability to control temperature, reactant concentrations, and many other things such as pressure and pH depending on the specific reactor involved. [1] Carefully analyzing past experiments enables chemical engineers to make changes to the reactor conditions that would make the reactions more efficient and effective. Figure 1: The Batch Reactor Above is a picture of the 1L batch reactor used in both experiments. The outer layer of the reactor is a water jacket with a dedicated temperature probe that constantly monitors the reactor’s