(7eu) Molecular Modelling for Catalytic Reaction Engineering | AIChE

(7eu) Molecular Modelling for Catalytic Reaction Engineering

Authors 

Varghese, J. J. - Presenter, Nanyang Technological University, Singapore (NTU)
Research Interests:

In course of my PhD and Post-Doctoral research I have maintained keen interest in fields like chemical vapour deposition synthesis of carbon nanostructures, photo-electro catalysis, biomass pyrolysis and so on and have been involved in research in molecular modelling for catalysis and reaction engineering in fields like methane activation and conversion and catalytic transformation of biomass derived feedstock.

Mechanistic insights on C-H bond activation and materials for methane chemistry

With recent discoveries of significant reserves of gas hydrates, my PhD work focussed on the chemistry of methane, as a step to contribute to realising a chemical supply chain around methane feedstock, replacing existing ones based on petroleum. In the thesis I showed that 1) high impact intermolecular collision of methane can result in their activation and direct bimolecular transformation to ethylene, unlike the unimolecular thermal dissociation and subsequent biradical coupling, 2) sub-nanometre clusters of copper and copper oxide are extremely active in dissociating methane unlike bulk copper which is inactive, with the former being effective in coupling reactions to form C2 hydrocarbons, and 3) vacancy defects and dopants significantly alter reactivity of the surface of metal oxides, with Ni vacancies and Li as a low valent dopant significantly increasing reactivity of nickel oxide for methane dissociation. Insights on C-H bond activation of methane resulting from non-catalytic high impact collisions and the dissociation process on nano-clusters and oxide surfaces of abundant transition metals are crucial to develop new processes and to screen and design efficient catalysts for its conversion to value added chemicals.

Mechanistic insights on multifunctional catalysis for chemicals from biomass and solvent effects in such transformations

Biomass forms a carbon neutral feedstock for producing a variety of fuels and chemicals which are currently derived from petroleum feedstock. My research efforts also span the chemical transformation of biomass derived sugars and alcohols to value added chemicals with focus on unravelling mechanistic details of the transformations on selected multifunctional homogeneous and heterogeneous catalysts and explaining the contribution of different solvents in altering reactivity and product selectivity. The projects I worked on include 1) homogeneous Cr catalysis for glucose isomerization to fructose, 2) non-equilibrium solvation and solvent dynamics during hydride transfer in glucose catalysed by Sn-beta, 3) catalytic glycerol oxidation to dicarboxylic acids on copper (II) oxide and 4) glycerol hydrogenolysis to propane diol on ReOx modified Ir catalyst.

Expertise and skills

  • Density Functional Theory (DFT), Møller–Plesset perturbation theory (MP), Coupled Cluster Theory, Classical Molecular Dynamics, Ab Initio Molecular dynamics (CPMD), Metadynamics
    • Potential/Free energy surfaces, transition states, reaction paths, charge transfer, electronic structure, bonding, energy decomposition, vibrational analysis, band structure of solids, solvation, dynamics, first principles X ray spectroscopic characterization

Publications

  • Jithin J. Varghese, Q. T. Trinh and Samir H. Mushrif, “Insights into the synergistic role of metal-lattice oxygen site pairs in four-centred C-H bond activation of methane: The case of CuO”, Catal. Sci. Tech., 6, 3984 – 3996, 2016
  • Jithin J. Varghese and Samir H. Mushrif, “First principles investigation of the dissociation and coupling of methane on small copper clusters: Interplay of collision dynamics and geometric and electronic effects”, J. Chem. Phys., 142, 184308, 2015
  • Samir H. Mushrif, Jithin J. Varghese, Chethan B.K., “Solvation Dynamics and Energetics of Intramolecular Hydride Transfer Reactions in Biomass Conversion”, Phys. Chem. Chem. Phys., 17, 4961-4969, 2015
  • Samir H. Mushrif, Jithin J. Varghese, Dion G. Vlachos, “Insights into the Cr(III) catalyzed isomerization mechanism of glucose to fructose in the presence of water using ab initio molecular dynamics”, Phys. Chem. Chem. Phys., 16, 19564-19572, 2014

Future direction

Computational catalysis over the years has become an integral part catalytic reaction engineering, where, the modelling work explains atomic and molecular phenomena and helps in computational screening of catalysts and solvents, together leading to design of more efficient catalytic reaction systems and processes. With thousands of new catalysts being discovered, their stability and recyclability are crucial for their commercial development and deployment. Computational effort in understanding and evaluating the stability and lifetime of catalysts in realistic operation conditions is lacking and this is a direction I would like to pursue. In this direction, I would like to work closely with experimental catalysis experts to develop multiscale models to understand catalyst deactivation and stability.

Teaching Interests:

Teaching Philosophy

‘Teaching is a process of learning to inspire others’. This is my philosophy on teaching. A successful teacher shares existing knowledge, induces curiosity in the students, inculcates the spirit of questioning and inspires the quest for advancing the state-of-the-art in science and technology

University teaching experience

The ‘University Teaching for Teaching Assistants’ course at NTU helped me reflect on how we as students learnt best. At NTU, I had opportunities to test myself, where I engaged under-graduate students in laboratory sessions as well as tutorial sessions for the course modules as a graduate teaching assistant. I engaged students for two laboratory modules: Tensile testing of materials and Analysis of chemical reactors. Being a teaching assistant for tutorial sessions in the core Chemical Engineering modules of Unit Operations (Principles of separation), Chemical Reaction Engineering and Fluid systems gave me the real flavour of university teaching.

Teaching methods and practises and student feedback

Short questions, discussions, facts and scenarios to ponder about, helped in getting active class participation, and encouraged students to ask questions, making the sessions lively and useful to the students. My focus on presenting a methodical approach to solve the problems encouraged critical thinking by the students rather than rote learning. The use of technology like Youtube videos, power point presentations, Microsoft Excel spreadsheets with mathematical functions to solve problems in addition to the conventional speech and black/white board based approach to teaching greatly enhanced the classroom experience. Frequent citing of examples from the process industry helped students appreciate the relevance of the subject and get acquainted with situations they might encounter in their professional life ahead. A rating of 4.5 and higher (on 5) based on feedback from over hundred students who attended the tutorials sessions is testimony to my good performance as a teacher.

Courses

As a chemical engineering graduate, with professional experience in operations of a petrochemical unit, I am confident of teaching all the core chemical engineering topics among which preference would be to teach Unit Operations and Separations, Fluid Systems, Heat and Mass transfer, Chemical Reaction Engineering, Process Equipment and Plant Design. With research expertise in molecular modelling for a wide range of focus areas, I would like to develop undergraduate courses like Fundamentals of Molecular Modelling and Molecular Modelling for Catalysis.