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New and Improved Green Experiments for the Organic Chemistry Lab Brian L. Groh Jason F. Pendleton, Duane M. Anderson, Mariya Nasiruddin, and Joel Heuton.

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Presentation on theme: "New and Improved Green Experiments for the Organic Chemistry Lab Brian L. Groh Jason F. Pendleton, Duane M. Anderson, Mariya Nasiruddin, and Joel Heuton."— Presentation transcript:

1 New and Improved Green Experiments for the Organic Chemistry Lab Brian L. Groh Jason F. Pendleton, Duane M. Anderson, Mariya Nasiruddin, and Joel Heuton Department of Chemistry and Geology Minnesota State University, Mankato July 30, 2006

2 Presentation Outline Lab Facilities and Constraints Experiment Evaluation Modified and New Experiments

3 Lab Facilities Students work on open bench tops Have access to hood space as needed Limited to students simultaneously New facility to be occupied in 2 years Plan for similar lab without need for routine individual hood space

4 Three Phase Transition to Greener Experiments Evaluate current and proposed labs objectively Modify existing labs with greener alternatives Develop new, greener lab alternatives

5 Lab Structure Multiple sections of 24 students 3h lab periods Preparative, reduced and microscale experiments “Cleaner” experiments done on larger scales Minimizes waste “Dirtier” or more “hazardous” labs done on smaller scales Minimizes waste and cost Increased safety Students work independently and are taught to properly treat and dispose of their own waste

6 Experiment Evaluation and s Examine all solvents and reagents and score current labs using objective criteria Create scores based on – NFPA codes factor in hazard points (e.g. mutagens, carcinogens, etc. not included in NFPA rating) factor in use of bio-based or renewable reagents and solvents Consider total waste generated

7 Modification Process Find known modifications or propose reasonable substitutions Better procedures, solvents or reagents Consider experiments that produce considerable waste Replace with catalytic reactions Modifications vary from simple to complex Solvent change (bromination experiment) Redesign of experiment (Glaser reaction) Experimentally verify modifications

8 Glaser-Eglinton-Hayes Coupling Original Glaser-Eglinton-Hayes procedure 1 Original Glaser-Eglinton-Hayes procedure 1 Longer, involved an additional filtration and water wash, required 4h Longer, involved an additional filtration and water wash, required 4h Alternative procedures 2,3 require heating Alternative procedures 2,3 require heating Modifications: Modifications: Simplify isolation procedure Simplify isolation procedure Solvent change: Ethanol vs. methanol Solvent change: Ethanol vs. methanol Base change: TMEDA vs. pyridine Base change: TMEDA vs. pyridine 1. Kenneth Williamson, Macroscale and Microscale Organic Experiments, 4th ed., Houghton Mifflin Co, Boston, MA, Ch 24, pp Ken Doxsee, Jim Hutchinson, Green Organic Chemistry, Thompson Learning Custom Publ., Mason, OH, 2002, pp Charles Wilcox, Jr. and Mary Wilcox, Experimental Organic Chemistry, 2 nd Ed., Prentice-Hall Publ. Englewood Cliffs, NJ, pp

9 Experiment Evaluation Score current labs using objective criteria Score current labs using objective criteria

10 Experiment Evaluation Comparison of NFPA ratings: Comparison of NFPA ratings: No Net Change

11 Experiment Evaluation Comparison of PELs and Specific Hazards: Comparison of PELs and Specific Hazards: Net Change (-2)

12 Experiment Evaluation Experiment totals: Experiment totals: Methanol/pyridine = 11 Methanol/pyridine = 11 Ethanol/TMEDA = 8 Ethanol/TMEDA = 8

13 Improved Glaser-Eglinton-Hayes Coupling Modifications Ethanol (95%) with TMEDA Ethanol (95%) with TMEDA Simplified isolation procedure Simplified isolation procedure Benefits: Benefits: Reduced amount of solvent for isolation Reduced amount of solvent for isolation Reduced amount of aqueous waste Reduced amount of aqueous waste Homogenous reaction Homogenous reaction Stunning color change (light green to midnight blue by completion) Stunning color change (light green to midnight blue by completion) Reaction time: min at room temperature (heating noted w/other procedures) * Reaction time: min at room temperature (heating noted w/other procedures) * Generally cleaner product in comparable yields Ken Doxsee, Jim Hutchinson, Green Organic Chemistry, Thompson Learning Custom Publ., Mason, OH, 2002, pp Charles Wilcox, Jr. and Mary Wilcox, Experimental Organic Chemistry, 2 nd Ed., Prentice-Hall Publ. Englewood Cliffs, NJ, pp This reaction can also be run in 75% ethanol!

14 Improved Glaser-Eglinton-Hayes Coupling Modifications Ethanol (95%) with TMEDA Ethanol (95%) with TMEDA Simplified isolation procedure Simplified isolation procedure Benefits: Benefits: Reduced amount of solvent for isolation Reduced amount of solvent for isolation Reduced amount of aqueous waste Reduced amount of aqueous waste Homogenous reaction Homogenous reaction Stunning color change (light green to midnight blue by completion) Stunning color change (light green to midnight blue by completion) Reaction time: min at room temperature (heating noted w/other procedures) * Reaction time: min at room temperature (heating noted w/other procedures) * Generally cleaner product in comparable yields Ken Doxsee, Jim Hutchinson, Green Organic Chemistry, Thompson Learning Custom Publ., Mason, OH, 2002, pp Charles Wilcox, Jr. and Mary Wilcox, Experimental Organic Chemistry, 2 nd Ed., Prentice-Hall Publ. Englewood Cliffs, NJ, pp This reaction can also be run in 75% ethanol 50% ethanol

15 Improved Glaser-Eglinton-Hayes Coupling Modifications Ethanol (95%) with TMEDA Ethanol (95%) with TMEDA Simplified isolation procedure Simplified isolation procedure Benefits: Benefits: Reduced amount of solvent for isolation Reduced amount of solvent for isolation Reduced amount of aqueous waste Reduced amount of aqueous waste Homogenous reaction Homogenous reaction Stunning color change (light green to midnight blue by completion) Stunning color change (light green to midnight blue by completion) Reaction time: min at room temperature (heating noted w/other procedures) * Reaction time: min at room temperature (heating noted w/other procedures) * Generally cleaner product in comparable yields Ken Doxsee, Jim Hutchinson, Green Organic Chemistry, Thompson Learning Custom Publ., Mason, OH, 2002, pp Charles Wilcox, Jr. and Mary Wilcox, Experimental Organic Chemistry, 2 nd Ed., Prentice-Hall Publ. Englewood Cliffs, NJ, pp This reaction can also be run in 75% ethanol 50% ethanol 25% ethanol

16 Improved Glaser-Eglinton-Hayes Coupling Modifications Ethanol (95%) with TMEDA Ethanol (95%) with TMEDA Simplified isolation procedure Simplified isolation procedure Benefits: Benefits: Reduced amount of solvent for isolation Reduced amount of solvent for isolation Reduced amount of aqueous waste Reduced amount of aqueous waste Homogenous reaction Homogenous reaction Stunning color change (light green to midnight blue by completion) Stunning color change (light green to midnight blue by completion) Reaction time: min at room temperature (heating noted w/other procedures) * Reaction time: min at room temperature (heating noted w/other procedures) * Generally cleaner product in comparable yields Ken Doxsee, Jim Hutchinson, Green Organic Chemistry, Thompson Learning Custom Publ., Mason, OH, 2002, pp Charles Wilcox, Jr. and Mary Wilcox, Experimental Organic Chemistry, 2 nd Ed., Prentice-Hall Publ. Englewood Cliffs, NJ, pp This reaction can also be run even in water!

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21 Experiment Evaluation Experiment totals: Experiment totals: Methanol/pyridine = 11 Methanol/pyridine = 11 Water/TMEDA = 6 Water/TMEDA = 6

22 New Experiment Candidate: Adipic Acid Synthesis Current experiment sequence: Current experiment sequence: Drawbacks: Drawbacks: Requires excess KMnO 4 (3g /g ketone!) Requires excess KMnO 4 (3g /g ketone!) Large quantities of MnO 2 (oxidizer) produced (1.8g /g ketone) Large quantities of MnO 2 (oxidizer) produced (1.8g /g ketone) Contaminated product (isolate by NaCl precipitation) Contaminated product (isolate by NaCl precipitation) Low yields (ave 33% est. on last step; ave 20% overall) Low yields (ave 33% est. on last step; ave 20% overall)

23 New Experiment: Catalytic Oxidation A Green Adipic Acid Synthesis Propose 1 – 1 g scale oxidation Propose 1 – 1 g scale oxidation Advantages Catalytic oxidation By-products: O 2, H 2 O Higher yields 1. Zhang, Shi-gang; Jiang, Heng; Gong, Hong; Sun, Zhao-lin Petroleum Science and Technology 2003, 21 (1-2),

24 Experiment Evaluation Scores: KMnO 4 method: 16 Includes KMnO 4, NaOH, NaHSO 3, celite H 2 O 2 method: 9 Includes H 2 O 2, Na 2 WO 4, sulfosalicylic acid

25 New Experiment: Catalytic Oxidation A Green Adipic Acid Synthesis Reaction – 1 g scale oxidation Reaction – 1 g scale oxidation Heat: Steam bath, overnight Heat: Steam bath, overnight No residual peroxide No residual peroxide 75% average isolated yield of pure adipic acid from cyclohexanone 75% average isolated yield of pure adipic acid from cyclohexanone

26 Co-catalysts Sulfosalicylic acid (23 mg) Sulfosalicylic acid (23 mg) Best yields – ave 75% Best yields – ave 75% Cleanest product Cleanest product Very water soluble Very water soluble Sodium bisulfate (30 mg) Sodium bisulfate (30 mg) Reduced yields (by ~ 60%) Reduced yields (by ~ 60%) Discolored product Discolored product Narrowed reaction time Narrowed reaction time Ascorbic acid (40 mg) Ascorbic acid (40 mg) Reduced yields (~ 30%) Reduced yields (~ 30%) Discolored product Discolored product Ligand can be neutralized and sewered

27 5 mL 7.5 mL 15 mL

28 New Experiment: Catalytic Oxidation A Green Adipic Acid Synthesis Reaction – 1 g scale oxidation Reaction – 1 g scale oxidation But, synthetic cyclohexanone sometimes gave poorer yields… But, synthetic cyclohexanone sometimes gave poorer yields…

29 Side reaction responsible for low yields According to procedure: According to procedure: Analysis by GC and GCMS indicates Analysis by GC and GCMS indicates Vigorous reaction gives 2-chlorocyclohexanone Vigorous reaction gives 2-chlorocyclohexanone High amounts correlate with poor yields of adipic acid High amounts correlate with poor yields of adipic acid

30 Catalytic Oxidation: A Green Adipic Acid Synthesis Proposed reaction pathway 1 Proposed reaction pathway 1 1. Based upon the work of Noyori and Fischer: Sato, K.; Aoki, M.; Noyori, R.; Science 1998, 281, Fischer, J.; Holderich, W.F. Appl. Cat. A: General 1999, 180, 435.

31 Catalytic Oxidation: A Green Adipic Acid Synthesis Waste reduction:

32 Summary: Green Adipic Acid Synthesis AdvantagesDisadvantages Improved Evaluation Score (9 vs. 16)Use of corrosive peroxide Yields are more than doubleComplex reaction mechanism Simple isolationLong heated reaction time Expt Atom Economy 60% vs 37% (theory) 45% vs 12% (observed) Waste reduction

33 S N 2 Experiment Candidate Synthesis of n-butyl bromide from n-butanol Synthesis of n-butyl bromide from n-butanol Drawbacks: Drawbacks: Low yields on a small scale Impure product Odor problems Use of concentrated sulfuric acid Goals: Goals: Develop new experiment that still teaches the S N 2 reaction High yields of pure product Simple experiment suitable for a beginning 3 h lab

34 Proposed S N 2 Experiment Use of PCl 5 Proposed reaction scheme Potential Advantages Solventless reaction One step Short reaction time Clean, high yield reaction Introduce column chromatography for purification

35 Experiment Evaluation Scores: NaBr/H 2 SO 4 method: 18 Includes NaBr, H 2 SO 4, H 2 O, NaHCO 3, 1-butanol, 1-chlorobutane PCl 5 method: 14 Includes PCl 5, pentane, H 2 O, NaHCO 3, 1-tetradecanol, 1- chlorotetradecane (note: hexane score = 4)

36 Synthesis of 1-chlorotetradecane from 1-tetradecanol Results: high yield – up to 92% (ave 80%) Highly pure >98% by GC analysis (crude) Short reaction time (40 min) No need to introduce column chromatography! Product can easily be analyzed by IR, GC By-products can easily be neutralized Solventless reaction – visual reaction

37 Reaction Mechanism is Relevant Gerrard, W.; Phillips, R. J. Chemistry & Industry 1952,

38 Reaction Highlights Analyze by GC for purity but… no need to introduce column chromatography! IR, H & 13 C NMR indicate high purity

39 Reaction Highlights Combine solid reagents

40 Reaction Highlights Mix with cooling

41 Reaction Highlights Heat in steam bath

42 Reaction Highlights Isolate by extraction

43 Experiment Summary AdvantagesDisadvantages Solventless reaction % Atom Economy (55 vs 50 for n-butyl bromide) High yield, pure (% AE*yield = 44 vs 30) (% AE*yield = 44 vs 30) More complex mechanism Improved evaluation score (14 vs 18) (14 vs 18) Visual reaction Minimal waste

44 Summary Evaluated labs objectively with respect to safety and green character Redesigned experiments while maintaining good yields Designed new experiments that minimize waste, reagent or solvent use Continue to look for greener alternatives and improvements – this is a continuing transition!

45 Acknowledgements Undergraduate Student researchers: Jason Pendleton Duane Anderson Mariya Nasiruddin Joel Heuton Organic Chemistry students for their participation and feedback. Minnesota State University, Mankato Center for Education, Teaching and Learning for partial funding of this work

46 New and Improved Green Experiments for the Organic Chemistry Lab Brian L. Groh Jason F. Pendleton, Duane M. Anderson, Mariya Nasiruddin, and Joel Heuton Department of Chemistry and Geology Minnesota State University, Mankato July 30, 2006 Website:

47 Experimental Procedures Procedures for the experiments outlined in this presentation may be requested from Brian Groh by at. The experiments will be available in a photo-essay type format on my website hopefully by fall semester Follow the “LabViews” link on the home page. Procedures for the experiments outlined in this presentation may be requested from Brian Groh by at The experiments will be available in a photo-essay type format on my website hopefully by fall semester Follow the “LabViews” link on the home Website:


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