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Monitoring Complex Reactions Using Calibration Free Techniques

Monitoring Complex Reactions Using Calibration Free Techniques. Selena Richards CPACT The University of Hull. Contents. Calibration Free Techniques (CFT’s) Aim Theory Catalytic Asymmetric Transfer Hydrogenation Reaction (CATHy) Introduction Experimental Results

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Monitoring Complex Reactions Using Calibration Free Techniques

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  1. Monitoring Complex Reactions Using Calibration Free Techniques Selena Richards CPACT The University of Hull

  2. Contents • Calibration Free Techniques (CFT’s) • Aim • Theory • Catalytic Asymmetric Transfer Hydrogenation Reaction (CATHy) • Introduction • Experimental • Results • Conclusion and Further Work

  3. Aim • No of reacting chemical constituents • By-products and / short lived intermediates • Kinetic profiles • Pure spectra profiles • Prediction of end-points • Monitoring and control

  4. Calibration Free Techniques (CFT’s) CFT’s are essentially based on Factor Analysis which is a multivariate technique for reducing matrices of data to their lowest dimensionality by the use of orthogonal factor space and transformation that yield predictions and / or recognizable factors

  5. Step 1 Data Reduction and Rotation Wavelengths (variables) Spectra (samples) Wavelengths PCA Step 2 FR Spectra PC loadings Step 3 PC- Scores

  6. Response Step 4 Pure spectra 1 2 1 2 factors Wavenumber concentration Concentration Time Data Reduction and Rotation

  7. Factor Analysis • Multicomponent System • Aλ = ελ1 c1 +ελ2c2 + …….+ ελ mcm • Linear additive signal • Pre-requisite of Factor Analysis methods • Decomposition X (A) = T (c) PT(ε) + E

  8. Wavelength Wavelength Wavelength 1 2 2 3 Time n-1 n n n Evolving Factor Analysis

  9. Rotation • After Decomposition…. • Need to obtain results which make chemical sense • Pure concentration profiles • Pure spectral profiles • Need to determine the rotation matrix X = T RR-1PT = C A

  10. y l k y11 k11 l11 x11 x Rotation • Factor rotation is the rotation of the defined space by a certain angle  • F =V*T R • Rotation matrix • Abstract Interpretable

  11. Alternating Least Squares • Pure spectra and concentration profiles • X = C ST • Solve S from concentration profiles • Constraint • Calculate C • Repeat until S and C stable

  12. Constraints • Criteria specific to domain of data • Non-negativity • Kinetic constraints • Selectivity • Closure • Criteria not specific to domain of data • Simplicity • Dissimilarity

  13. CATHy • Asymmetric reduction in nature • Highly stereo-selective • CATHy • General method • Economical • Technically simple • Non-hazardous organic molecules • Reduction of cyclic imines

  14. CATHy of 1-Methyl-3,4-dihydroisoquinoline

  15. Experimental • Reaction mixture • Background • Acetonitrile • TEAF [distilled formic acid 1.0M: distilled triethylamine 0.4M] • Sample • 1-methyl-3,4-dihydroisoquinoline [0.25M] • Reaction initiated: • Dichloro(pentamethylcyclopentadienyl) rhodium(III) dimer 0.0005M • (1R,2R)-(-)-N-p-tosyl-1,2-diphenylethylenediamine 0.001M

  16. Reaction Profile

  17. Results • Spectral profiles

  18. Results • Kinetic Profiles

  19. Results • Kinetic Parameters: • Exhaustive Kinetic Fitting • Consecutive reaction • Order (x,y,z) • Stiochiometric ratios (a,b,c,d)

  20. Conclusion • Reaction monitored in-situ • Eliminates need for constant sampling • Data Analysis • HPLC, FTIR and chemometric data consistent • Carbon dioxide spectrum obtained from CFT • Reaction mechanism not fully resolved

  21. Further Work • Real Time Monitoring • Recursive Regression Methods • Adaptive Kalman filter • Predict evolution of constituents through time • Aid monitoring and control

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