Reactive separation for dimethylnaphthalene isomerization

Abstract

Polyethylene naphthalate (PEN) is one of the enginerring plastics with superior properties suitable for utilizing in many innovative applications. However, its widepread utilizations are still limited by its relatively high cost. One of the factors bolstering the polymer price is the price of 2,6-dimethylnaphthalene (2,6-DMN), which is a precursor for the polymer synthesis. Commercially, 2,6-DMN is synthesized using the BP Amoco process, in which a complex synthesis route with a themodyamical limitation and freeze crystallization are employed. As a result, the low availability and high utility used for the production of 2,6-DMN entail its high cost. In this study, attempts to demonstrate a non-energy intensive alternative for producing the chemical were made. Catalytic ismoerization of 1,5- to 2,6-DMN and adsorptive separation wer of interest. Insight studies to understand both systems were individually performed. It was found that the maximum yield of the isomerization can be achieved at significantly lower temperatures and the adsorptive purification of 2,6-DMN can be accomplished in rejective system by using toluene as a media. The combinations of the isomerization and adsorption were also demonstrated in two different approaches and their potential to produce high purity 2,6-DMN have been proven under different operating conditions. For instance, performing the isomerization in equilibrium is suitable for the system that connects the adsorption unit right after the isomerization with the selected adsorbent, catalyst and desorbent, while the reactive adsorption should be carried out at the appropriate temperatures below the equilibrium.