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S TUDY O F T HE S ECOND V IRIAL C OEFFICIENTS : N EW C HALLENGE F OR QSPR

S TUDY O F T HE S ECOND V IRIAL C OEFFICIENTS : N EW C HALLENGE F OR QSPR. Elena Mokshyna , Victor E. Kuz’min , Vadim I. Nedostup. W HY C HALLENGE ?. The compressibility factor is expressed as a series expansion in either density (reciprocal molar volume) or pressure :

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S TUDY O F T HE S ECOND V IRIAL C OEFFICIENTS : N EW C HALLENGE F OR QSPR

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  1. STUDY OF THE SECOND VIRIAL COEFFICIENTS:NEW CHALLENGE FOR QSPR Elena Mokshyna, Victor E. Kuz’min, Vadim I. Nedostup

  2. WHY CHALLENGE? • The compressibility factor is expressed as a series expansion in either density (reciprocal molar volume) or pressure: • Main purposes: • Development of approach to QSPR of T-dependent properties • Calibration of the descriptors • Prediction for new complex organic compounds

  3. EXPERIMENTAL DATA • Number of compounds: 262 • Number of points: 4787 • Range of virial coefficients: -5891 – 391 cm3/mol • Range of temperatures: 110 – 773 K

  4. DESCRIPTORS & MODELLING TECHNIQUES • SiRMSdescriptors: • Temperature as a single descriptor: B = f(T) • Two-layer QSPR model: a = f(descriptors) b = f(descriptors) B = f(a, b)

  5. STATISTICAL ANALYSIS • Various statistical methods: MLR (Multi-Linear Regression) PLS (Projection on Latent Structures) RF (Random Forest) SVM (Support Vector Machines) with radial basis function kernel • Rigorous 3x5-fold stratified external cross-validation Training set Test set ! Data on virial coefficient of compound under all the temperatures are put in the test set

  6. RESULTSforB = f(T) R2ws = 0.87 R2ts = 0.68 R2ws = 0.53 R2ts = 0.19 R2ws = 0.94 R2ts = 0.71 R2ws = 0.71 R2ts = 0.45

  7. RESULTSforB = f (a,b)a = f(descriptors), b = f(descriptors) R2ws = 0.95 R2ts = 0.75 R2ws = 0.88 R2ts = 0.51 R2ws = 0.98 R2ts = 0.85 R2ws = 0.90 R2ts = 0.72

  8. EXPERIMENTAL ERRORSVS. ERRORSOF MODELS

  9. Relative Variable Influence

  10. Influential fragments Some examples from the generated fragments library : * * * * *

  11. So…. MISSION IS POSSIBLE, BUT CHALLENGE IS NOT COMPLETED!

  12. Thank you for the attention!

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