First principles computational study on hydrolysis of water-reactive - - PowerPoint PPT Presentation

▶
first principles computational study on hydrolysis of
SMART_READER_LITE
LIVE PREVIEW

First principles computational study on hydrolysis of water-reactive - - PowerPoint PPT Presentation

Nov 18, 2022 98 likes •261 views

First principles computational study on hydrolysis of water-reactive chemicals phosphorus trichloride and oxychloride (PCl 3 and POCl 3 ) 15 th June 2018 Hyunwook Jung, Joonhee Kang, Hoje Chun, Byungchan Han Department of Chemical and

slide-1
SLIDE 1

First principles computational study on hydrolysis of water-reactive chemicals phosphorus trichloride and oxychloride (PCl3 and POCl3)

Hyunwook Jung, Joonhee Kang, Hoje Chun, Byungchan Han

Department of Chemical and Biomolecular Engineering, Yonsei University, 03722, Seoul, Republic of Korea

15th June 2018

slide-2
SLIDE 2

Motivation

PCl3

(Phosphorus Trichloride)

POCl3

(Phosphorus Oxychloride)

4 2 ₩ 3 2 ₩

  • Chemical Properties
  • Colorless Liquid
  • Density: 1.576g g/cm3
  • Vapour pressure: 100mmHg
  • Common Uses
  • Chemical Properties
  • Colorless Liquid
  • Density: 1.576g g/cm3
  • Vapour pressure: 100mmHg
  • Common Uses
  • Y. Segall et al. Chem. Res. Toxicol. 2003, 16, 350-356

 World production of PCl3 & POCl3 exceeds more than 1/3 million tons annually  They are essential chemicals in industry because of their versatile uses

Pesticides Flame Retardant Chelating Agent Plastic Additives N-type Dopant Solar Cell IC Optical Fiber 2

slide-3
SLIDE 3

Motivation

Tianjin Explosion (China) Deaths: 173 Cause: NaCN, NH4NO3, … 12 Aug. 2015 2 Dec. 1984 Bhopal Disaster (India) Death: at least 3787 Cause: Methyl isocyanate Gumi HF leakage (Korea) Deaths: 5 Cause: HF 27 Sep. 2012 21 Sep. 2001 AZF Disaster (France) Death: 30 Cause: NH4NO3

Chemical disasters from unexpected reaction

3

 Yet, reaction database is far from completeness, which hinders safe control of chemical accident

slide-4
SLIDE 4

Motivation

4

Physicochemical, Toxicological, Ecotoxicological Properties Experiments, Animal testing Computer Simulation, Ab-initio calculation Conventional approach Alternative approach

REACH Regulations in EU (Registration, Evaluation, Authorization, and Restriction of Chemicals)

Carlos Nieto-Draghi et al. 2015. Chem. Rev. 115 (24) 13093-13164

Experiment Ab-initio Calculation Reliable but, Not realistic in time, cost, feasibility, and safety Fast, low cost, and very safe. Measurement methods of required physicochemical properties

slide-5
SLIDE 5

Outline

  • 1. Motivation
  • 2. Model Systems and Computational Details
  • 3. Results and Discussion
  • Water-catalyzed hydrolysis
  • Structural analysis
  • Solvent effect by water and charge analysis
  • Potential energy surface profile
  • 4. Summary
  • 5. Acknowledgement

5

slide-6
SLIDE 6

Model Systems

Calculated using: Gaussian09 B3LYP 6-31+g(d,p)

Model Systems and Computational Details

6

Grotthuss Mechanism; three-fold role of water

water Reactant Solvent Catalyst

H2O PCl3

slide-7
SLIDE 7

Water-Catalyzed Hydrolysis

Free energy diagram

PCl3(g) + 3H2O(g) → H3PO3(g) + 3HCl(g) POCl3(g) + 3H2O(g) → H3PO4(g) + 3HCl(g) PCl3 POCl3 1st step

  • 5.88
  • 8.85

2nd step

  • 0.19
  • 9.84

3rd step

  • 3.98
  • 8.34

Tautomerization

  • 3.67
  • ΔH
  • 13.73 (-15.44)
  • 27.03 (-24.1)

Table 1. Reaction heat for each steps of the hydrolysis and experimental data (in parenthesis)

7

  • H. Jung et al. Journal of Hazardous Materials 341 (2018) 457-463
slide-8
SLIDE 8

Structural Analysis

Torsional angle as key-descriptor of kinetics

Step Torsional Angle PCl3 Torsional Angle POCl3 High ∆‡ Low ∆‡ High ∆‡ Low ∆‡ 1st Cl1Cl2PCl3 150.26˚ 91.63˚ Cl1Cl2PO 157.87˚ 177.57˚ 2nd Cl1Cl2PO 148.70˚ 91.16˚ O1ClPO2 151.06˚ 167.66˚ 3rd ClO1PO2 146.33˚ 79.07˚ ClO1PO2 150.96˚ 151.89˚

Table 2. Torsional angle around central Phosphorus in the transition states See-saw Trigonal bipyramidal

CCPCl 90° CC 180°

8

  • H. Jung et al. Journal of Hazardous Materials 341 (2018) 457-463

° °

jh1

slide-9
SLIDE 9

Slide 8 jh1 sp3 -> sp3d state로 전환된다는 내용을 좀더 잘 표현할 필요가 있음.

jung hyunwook; 12/6/2018

slide-10
SLIDE 10

Solvent Effect by Water: Charge Analysis

Charge Density Distribution  Hybridization shift(sp3→sp3d) is qualitatively confirmed

9

  • H. Jung et al. Journal of Hazardous Materials 341 (2018) 457-463
slide-11
SLIDE 11

10

‡

PCl3+n·H2O PCl2(OH)+HCl POCl3+n·H2O

‡ ‡

POCl2(OH)+HCl

 Typical gas phase SN2 reaction has double-well PES profile (PCl3)  POCl3 has triple-well PES profile; Due to additional coordination by double bonded Oxygen

Potential Energy Surface Profile

  • H. Jung et al. Journal of Hazardous Materials 341 (2018) 457-463
slide-12
SLIDE 12

Summary

 Adjacent water molecules play key role as a catalyst toward hydrolysis reaction via proton transfer.  Torsional angle around phosphorus atom is key-descriptor of the kinetics.  Hybridization of phosphorus is shifted from sp3 to sp3d at transition state.  Activated complex with charge separation was more stabilized by water.  PCl3 and POCl3 have different potential energy profile due to different coordination around phosphorus.

11

  • H. Jung et al. Journal of Hazardous Materials 341 (2018) 457-463
slide-13
SLIDE 13

Acknowledgement

This work was supported by

  • The Korea Ministry of Environment (MOE) as “the Chemical Accident

Prevention Technology Development Project”

  • Global Frontier Program through the Global Frontier Hybrid Interface

Materials (GFHIM) (2013- M3A6B1078882)

  • The Defense Industry Technology Center (DITC) for financial support from

contract No.UC15000ID

12

slide-14
SLIDE 14

Thank you for your attention!!

13

Contact Info. Hyunwook Jung Email: jungsdao@gmail.com Phone: +82-10-2780-2396