MMRL

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Name: Ruchi GoyalRoll No.: 5582

IV semester project work under the supervision of

Dr. Anurag Prakash Sunda(DST INSPIRE Faculty)

Molecular Modeling and Materials Research Laboratory (MMRL)

Molecular Dynamics Simulations of CO2 in 1-hexyl-3-methylimidazolium

bis(trifluoromethylsulfonyl)imide Ionic Liquid

DEPT. OF CHEMISTRY, SCHOOL OF CHEMICAL SCIENCECENTRAL UNIVERSITY OF HARYANA

HARYANA PIN - 123031 INDIAMay 2016

MMRLIntroduction

Emission of co2 in environment by human activity like as coal fired plant, industry cause global warming, climate change etc. The concentration of co2 in environment is gradually increase

. To reduce the concentration of co2 in environment by a technique called capture . Co2 is captured by physical absorption and chemical absorption.

In chemical absorption co2 is captured by ionic liquid. Due to their good property like thermal stability, low vapor pressure, non volatile, non flammable, liquid over large range, tunable solvent property. These are easy to buy and simple to prepare.

In this project I used the 1-hexyl-3-methylimidaolium cation and bis(trifluoromethylsulfonyl)imide anion.

Structure of ionic liquid are shown below:

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MMRLUse of ILs

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• Ionic liquid used for synthesis and catalysis

• Use as solvent (toxic gas storage and transport)

• Electrochemical(fuel cell{Li-ion battery}, Metal electroplating)

• Engineering fluids

• Biotechnology

• Sensor

• Extraction of organic solvent

MMRLComputational Details

MD Package : GROMACS 4.5.4

Time Step: 1 ps

No. of steps: 104 (1 ns)

Force-Field : OPLS –AA

Energy minimization: Steepest-descent method

Ensemble averaging : NPT

Thermostat : velocity rescale

Coupling time = 0.1 ps

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Configuration No. of Cation No. of Anion CO2 molecules Total no. of atoms

Mixture -A 620 300 600 1520

Mixture -B 1240 600 1200 3040

All the simulations were performed on single core CPU due to non-availability of computing resources at CUH.

MMRLVisual Inspection

Initial configurations

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MMRLDensity calculated from MD simulations

• The variation of density mix-A and mix-B are shown in figure

• Average value of density of mix-B is more as compared to mix-A.

• Because of number of ion pair is increased in mix-B due to which mass is increased hence density increased.

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Density (g cm-3)

Mixture -A 0.958889

Mixture -B 1.000031

MMRLRadial distribution function

• Radial distribution function, (or pair correlation function) g(r) in a system of particle(atom, molecule, ions) describe how density varies as a function of distance from reference particle.

• g(r) gives the probability of finding particle in the distance r from another particle • It is computed from MD

Simulation.• Rdf is calculated for various

interionic interaction for

Mix-A and Mix-B between the

following:-

a) N(Hexyl)-O(CO2)

b) N(methyl)-O(CO2)

c) N(anion)-O(CO2)

d) N(methyl)-N(anion)

and tell there is more interaction

in a),b)&c) but less in d)

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MMRLDiffusion

Diffusion rate is calculated with the help of MSD. In graph -1 diffusion rate of co2 is more in case of mix-B. In mix-A &mix-B diffusion rate for anion is more as compared cation.

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D ( 10-5 cm2 s-1) Cation Anion CO2

Mixture -A 0.0901 0.1206 1.4445

Mixture -B 0.1206 0.3453 3.2006

MMRLConclusions and future scope of the work

- Conclusions

1 MD simulation is used for ion pair and solvent in GROMACS-4.5.4.

2 In mix-A 20 ion pair with 200 CO2 and mix-B 40 ion pair with 400 co2.

3 Average density value for mix-B is more as compared to mix-A.

4 Interionic interaction of cation and anion is computed with the help of rdf.

- Future scope of the work

1 In future, I will use different R group attached to imidazolium based ionic liquid to

capture co2.

2 I will study with different ionic liquid with alkanol amine blend with different

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MMRLAcknowledgement

Central University of Haryana

Dr. Anurag Prakash Sunda (DST INSPIRE Faculty)

HOD, Chemistry

Faculty members, Dept. of Chemistry

GROMACS: MD Package

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MMRL

Thanking You

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