Drexel University Researcher's Report

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A 10-15 minute presentation on my research conducted in the chemistry department of Drexel University for students interested in participating in undergraduate research.

A 10-15 minute presentation on my research conducted in the chemistry department of Drexel University for students interested in participating in undergraduate research.

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  • http://onschallenge.wikispaces.com/EXP324
  • http://onschallenge.wikispaces.com/EXP321
  • http://onschallenge.wikispaces.com/EXP229http://onschallenge.wikispaces.com/EXP255
  • What makes a solvent optimal: bp, freezing point, etc. Sol at bp (if too low, impractical).
  • http://onschallenge.wikispaces.com/Benzoic+acid+-+AbrahamMake slide clearer
  • http://lxsrv7.oru.edu/~alang/solubility/soltemp.php?csids=555548&cs=0.092&solvent=ethanol&solmp=-114.1&solbp=78.2&limreact=0.3&limprod=0.03http://onschallenge.wikispaces.com/AbrahamDescriptorsModel003Don’t use an ethanol/water mixture, use another solvent Assumption of model: At melting point, solute is micible with solvent
  • Mention NMR method
  • Link to recrystallization page and webservices
  • http://lxsrv7.oru.edu/~alang/solubility/soltemp.php?csids=555548&cs=.624&solvent=ethyl%20acetate&solmp=-83.6&solbp=73.9&limreact=0.3&limprod=0.03State from bp to rtWrite sol at 25C and sol at bp
  • http://usefulchem.wikispaces.com/D-EXP022From a library of derivatives, it was the hop hit for the docking site of taxol
  • http://showme.physics.drexel.edu/onsc/models/solventselector.php?csids=28190813
  • http://usefulchem.wikispaces.com/EXP286
  • Small trace of benzene in nmrBenzene in cdcl315Hz coupling

Transcript

  • 1. Using the Abraham Model to Predict Organic Solubility to Determine a Recrystallization Solvent Researchers’ Report January 16, 2013 Matthew McBride Undergraduate Chemistry Major Drexel University Bradley Research Group
  • 2. Advantages of OpenNotebook Science for Undergraduate Research Gain organization skills and learn how to properly present experiments Receive timely feedback and corrective input Documentation of a student’s contribution to a project
  • 3. Organization and Presentation Updating the log the day the experiment is performed requires a student to keep an organized record of the lab work Eliminates long term reliance on handwritten notes and allows the log to be recorded when the experiment is still fresh in the student’s memory (http://onschallenge.wikispaces.com/EXP324)
  • 4. Organization and Presentation Teaches a student how to identify the critical elements of an experiment (http://onschallenge.wikispaces.com/EXP321)
  • 5. Correction and Input Using ONS allows the student to receive needed advice and guidance from the mentor directly on the experiment’s page Allows the student to understand where an error was made and how to avoid repeating the mistake (http://onschallenge.wikispaces.com/EXP255) (http://onschallenge.wikispaces.com/EXP229)
  • 6. Documentation Allows a student’s work and contribution to a project to be documented Provides graduate schools with the ability to view exactly what research an applicant has conducted (http://onschallenge.wikispaces.com/list+of+experiments)
  • 7. Solubility Important when choosing a recrystallization solvent Accurate solubility predictions for a compound allows the optimal solvent to be used
  • 8. Preferred Solvent Characteristics Does not react with the compound being recrystallized High solubility at boiling point, but low solubility at room temperature A boiling point that allows for easy drying of the product Miscibility with water
  • 9. Predicting Solubility with Abraham Descriptors Five descriptors for each solute and each solvent The descriptors for over 80 solvents, including some ethanol/water mixtures, are known Descriptors for a solute can be experimentally determined by measuring the solubility in 5 solvents Descriptors for a solute can be predicted using AD Model003 Using the solute descriptors, the solubility in any of the solvents with known descriptors can be predicted [William Acree](http://onschallenge.wikispaces.com/Benzoic+acid+-+Abraham)
  • 10. Solubility Predictions Using ONS Webservices, can list the predicted solubility for a compound Trans-dibenzalacetone (http://showme.physics.drexel.edu/onsc/models/solventselector.php?csids=555548) Solvent Model003 (M) AD Measured (M) Experimental (M) BP (°C) (www.chemspider.com/55 5548) [Andrew Lang]
  • 11. Solubility Curves Using a melting point, temperature dependent solubility curves are generated Assumes that at the melting point the compound is miscible with the solvent Solubility in Ethanol (Concentration M vs. Temperature °C) (http://showme.physics.drexel.edu/onsc/models/solventselector.php?csids=555548)[Andrew Lang]
  • 12. Temperature Controlled Shake Flask Method Add solute to the vials with the solvent and allow to shake in the 25°C water bath (http://onschallenge.wikispaces.com/e xp324)
  • 13. Temperature Controlled Shake Flask Method Measure the solubility using HNMR Need to take two consecutive measurements without the solubility changing to confirm the solution is saturated (http://onschallenge.wikispaces.com/EXP311)
  • 14. Measuring Solubility with NMR Compare integration of solute and solvent peaks in saturated solutions using google app scripts 1.5M Saturated solution of dibenzalacetone in THF Dibenzalacetone THF (http://onschallenge.wikispaces.com/EXP308) [Andrew Lang]
  • 15. Benefits of Solubility Curves These temperature dependent solubility curves allow a solvent with the greatest difference between solubility at room temperature and at the boiling point to be used Reduces reliance on only recrystallizing in solvents listed in literature Optimizes the process of choosing a recrystallization solvent [Andrew Lang]
  • 16. Example The solvents used to recrystallize compounds in organic teaching labs can be improved Trans-dibenzalacetone Aldol condensation between two molecules of benzaldehyde and one molecule of acetone (http://showme.physics.drexel.edu/onsc/reactionattempts/advancedsearch.php?compound=&solvent=&reactiontype =&researcher=Matthew+McBride) [Andrew Lang]
  • 17. Dibenzalacetone First recrystallized in ethyl acetate in 1906 Recrystallized in ethyl acetate in Organic Syntheses (Straus and Ecker, Ber. 39, 2988 (1906))
  • 18. Organic Teaching Labs Many recrystallize in ethyl acetate Is there a different solvent that could be used? (http://classes.kvcc.edu/chm230/MIXED%20ALDOL%20CONDENSATION.pdf) (http://www.xula.edu/chemistry/documents/orgleclab/Aldol_notes.pdf)
  • 19. SmartPhone App This app predicts the recrystallization yields of any compound in different solvents using the solubility curves: Provides experimental and predicted values for melting point and LogP [Andrew Lang] (http://onschallenge.wikispaces.com/recrystallization)
  • 20. SmartPhone App Enter compound identification (SMILES, CSID, name…etc), and desired parameters (http://onschallenge.wikispaces.com/rec ation) [Andrew Lang]
  • 21. SmartPhone App Lists solvents and their predicted recrystallization yield Prediction is generated by the temperature (http://onschallenge.wikispaces.com/recrystalliz ation) [Andrew Lang]
  • 22. Comparison Ethyl acetate (predicted yield of 69%) vs ethanol (predicted yield of 91%) Ethyl acetate Ethanol 0.09M 1.1M 0.62M 2.06M (http://showme.physics.drexel.edu/onsc/m odels/solventselector.php?csids=555548) [Andrew Lang]
  • 23. Solubility at Boiling Cannot be too low or an impractical recrystallization solvent Developing a novel recrystallization method using 1-octanol (boiling point: 195°C) and then washing with pentane (boiling point: 35°C) The ability to heat 1-octanol to higher temperatures increases the yield of the recrystallization
  • 24. Designing reactions using solubility These solubility tools can be used to choose a solvent for a reaction Finding a solvent in which the reactants are soluble, but the product is insoluble. This allows the product to be recovered by a simple filtration
  • 25. Example Derivatives of dibenzalacetone may be synthesized by altering the aldehyde used From a library of derivatives, the following compound was the top hit for the docking site of Taxol Uses phenanthrene-9-carboxaldehyde (http://usefulchem.wikispaces.com/D-EXP022) (http://www.chemspider.com/28190813) [Andrew Lang]
  • 26. Search Literature Perform a Reaxys© search to determine availability of synthesis procedures No results
  • 27. Synthesis Planning Desire a solvent that the aldehyde is soluble in, but the product is not The product was predicted as having very low solubility (<0.000M) in all solvents NaOH used as the catalyst, so needs to be soluble in the solvent (http://showme.physics.drexel.edu/onsc/models/solventselector.php?csids=281908 13) [Andrew Lang]
  • 28. Synthesis Planning NaOH is soluble in methanol, so check aldehyde solubility Phenanthrene-9-carboxaldehyde Solvent Model003 (M) AD Measured (M) Experimental (M) BP (°C) (http://showme.physics.drexel.edu/onsc/models/solventselector.php?csids=70806) (http://www.chemspider.com/708 06) [Andrew Lang]
  • 29. Synthesis Planning Conclusion: Using methanol as the reaction solvent should allow the aldehyde be dissolved into solution, but will cause the product to precipitate
  • 30. Synthesis Created an approximately 0.016M solution of phenanthrene-9- carboxaldehyde in methanol Added acetone and then a large excess of NaOH (catalyst) to the reaction mixture Stirred mixture without heat over two days (http://usefulchem.wikispaces.com/EXP286)
  • 31. Product Reaction mixture: (http://usefulchem.wikispaces.com/EXP286)
  • 32. Crude Product Following suction filtration: 0.0834 g of yellow crystals (http://usefulchem.wikispaces.com/EXP 286)
  • 33. Recrystallization Used benzene Melting Point: 264-265° (http://usefulchem.wikispaces.com/EXP286)
  • 34. HNMR Spectrum of product (http://usefulchem.wikispaces.com/EXP286) 16Hz Trans Coupling Benzene peak in CDCl3 (http://www.ch emspider.com/ 28190813) [Andrew Lang]
  • 35. Summary Open Notebook Science provides advantages to an undergraduate researcher Measured and predicted solubilities can be used to optimize recrystallizations Predicted solubilities can be used to plan the synthesis and optimize the recovery of the product
  • 36. Further Information http://onschallenge.wikispaces.com/ http://usefulchem.wikispaces.com/ http://onswebservices.wikispaces.com/