Title: Batch-to-Continuous Transition in Specialty Chemicals Industry: Intensified Dispersants Production

 Abstract: The specialty chemicals industry to-date is largely operating using decades old technology based on large-volume batch reactors of tens to hundreds of thousands of gallons in capacity. This technology is simple but highly inefficient given the advancement in science and engineering over the years. There is a need to improve the cost, energy, and atom efficiency of the processes and reduce their environmental footprint. Hence, the industry is currently undergoing a paradigm shift, moving away from traditional manufacturing approaches to highly intensified, modular, and cleaner processes.

Succinimide dispersants are a type of specialty chemicals used in various industries like automotive, hydraulic fluids, and metalworking, and are till-date produced using large volume (~10k-50k gal) batch reactors. Among these, Polyisobutylene succinic anhydride (PIBSA)-based dispersants are highly efficient in preventing sludge and deposit formation, making them a key component in automobile engine oils. They are formed by reacting PIBSA with polyamines to yield PIB-succinimide as dispersant products. In prior studies by our group, a batch-to-continuous (B2C) transition of PIB-succinimide dispersants was demonstrated using a reactor-separator system. In the first part of my thesis, the potential of hydrodynamic cavitation reactor (HCR) technology is evaluated as a novel reactor concept for succinimide dispersants production. Systematic studies were undertaken to evaluate the thermal, mixing, and reactive performance of the HCR. As part of the proposed work, a kinetic model for the thermal effect of cavitation is being developed.

In the second part of my thesis work, I am focusing on the B2C transition of the starting material PIBSA, which is also currently produced using large-volume batch reactors. Formed by reacting PIB with Maleic anhydride (MAA), the production of PIBSA poses several challenges – i) poorly miscible and highly viscous reaction mixture; ii) undesired side reactions due to temperature sensitivity of MAA and its high reactivity with acidic and basic functionalities; and iii) slow kinetics at typical operating conditions, resulting in long reaction times (>10 hours). Our approach is to first address the issues of mixing and undesired side reactions, followed by acquiring robust high temperature reaction kinetics (which are unknown to-date). The kinetic information will then act as a guide towards developing a suitable continuous process.

MAA is high carbon footprint chemical produced in large quantities globally (2.8 MMT in 2021). It is widely produced via oxidation of n-butane which emits 1.5 times as much CO2-eq (by wt.) per gram of MAA produced. PIBSA being a large volume dispersant precursor formed using MAA, hence has a large carbon footprint. Therefore, there is a need to develop non-MAA based dispersant precursors as replacements for PIBSA. One such potential candidate is Polyisobutylene Carboxylic Acid (PIBCA) that can be synthesized from PIB via a two-step reaction scheme – isomerization followed by the highly selective and well-established ozonolysis reaction. The final part of my proposed work aims to address the challenging step of isomerization of PIB by screening various precious and non-precious metal catalysts.

Chair:

Dr. Götz Veser

Department of Chemical and Petroleum Engineering, University of Pittsburgh

Committee Members:

 Dr. Robert Enick

Department of Chemical and Petroleum Engineering, University of Pittsburgh

Dr. Lei Li

Department of Chemical and Petroleum Engineering, University of Pittsburgh

Dr. Vikas Khanna

Department of Civil and Environmental Engineering, University of Pittsburgh        

Dr. Nico Proust

R&D Process Innovation, The Lubrizol Corporation