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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 Department of Chemistry and Geology Minnesota State University, Mankato [email protected] July 30, 2006. Presentation Outline.

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new and improved green experiments for the organic chemistry lab
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

[email protected]

July 30, 2006

presentation outline
Presentation Outline
  • Lab Facilities and Constraints
  • Experiment Evaluation
  • Modified and New Experiments
lab facilities
Lab Facilities
  • Students work on open bench tops
  • Have access to hood space as needed
    • Limited to 12-14 students simultaneously
  • New facility to be occupied in 2 years
    • Plan for similar lab without need for routine individual hood space
three phase transition to greener experiments
Three Phase Transition to Greener Experiments
  • Evaluate current and proposed labs objectively
  • Modify existing labs with greener alternatives
  • Develop new, greener lab alternatives
lab structure
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
experiment evaluation
Experiment Evaluation

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
modification process
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
glaser eglinton hayes coupling
Glaser-Eglinton-Hayes Coupling
  • Original Glaser-Eglinton-Hayes procedure1
    • Longer, involved an additional filtration and water wash, required 4h
    • Alternative procedures2,3 require heating
  • Modifications:
    • Simplify isolation procedure
    • Solvent change: Ethanol vs. methanol
    • Base change: TMEDA vs. pyridine

1. Kenneth Williamson, Macroscale and Microscale Organic Experiments, 4th ed., Houghton Mifflin Co, Boston, MA, 2003. Ch 24, pp. 335-337.

2. Ken Doxsee, Jim Hutchinson, Green Organic Chemistry, Thompson Learning Custom Publ., Mason, OH, 2002, pp 143-152.

3. Charles Wilcox, Jr. and Mary Wilcox, Experimental Organic Chemistry, 2nd Ed., Prentice-Hall Publ. Englewood Cliffs, NJ, 1995. pp 349-352

experiment evaluation9
Experiment Evaluation
  • Score current labs using objective criteria
experiment evaluation10
Experiment Evaluation

No Net Change

  • Comparison of NFPA ratings:
experiment evaluation11
Experiment Evaluation
  • Comparison of PELs and Specific Hazards:

Net Change (-2)

experiment evaluation12
Experiment Evaluation
  • Experiment totals:
    • Methanol/pyridine = 11
    • Ethanol/TMEDA = 8
improved glaser eglinton hayes coupling
Improved Glaser-Eglinton-Hayes Coupling
  • Modifications
    • Ethanol (95%) with TMEDA
    • Simplified isolation procedure
  • Benefits:
    • Reduced amount of solvent for isolation
    • Reduced amount of aqueous waste
    • Homogenous reaction
    • Stunning color change (light green to midnight blue by completion)
    • Reaction time: 40-60 min at room temperature (heating noted w/other procedures)*
    • Generally cleaner product in comparable yields

This reaction can also be run in 75% ethanol!

Ken Doxsee, Jim Hutchinson, Green Organic Chemistry, Thompson Learning Custom Publ., Mason, OH, 2002, pp 143-152.

Charles Wilcox, Jr. and Mary Wilcox, Experimental Organic Chemistry, 2nd Ed., Prentice-Hall Publ. Englewood Cliffs, NJ, 1995. pp 349-352

improved glaser eglinton hayes coupling14
Improved Glaser-Eglinton-Hayes Coupling
  • Modifications
    • Ethanol (95%) with TMEDA
    • Simplified isolation procedure
  • Benefits:
    • Reduced amount of solvent for isolation
    • Reduced amount of aqueous waste
    • Homogenous reaction
    • Stunning color change (light green to midnight blue by completion)
    • Reaction time: 40-60 min at room temperature (heating noted w/other procedures)*
    • Generally cleaner product in comparable yields

This reaction can also be run in 75% ethanol 50% ethanol

Ken Doxsee, Jim Hutchinson, Green Organic Chemistry, Thompson Learning Custom Publ., Mason, OH, 2002, pp 143-152.

Charles Wilcox, Jr. and Mary Wilcox, Experimental Organic Chemistry, 2nd Ed., Prentice-Hall Publ. Englewood Cliffs, NJ, 1995. pp 349-352

improved glaser eglinton hayes coupling15
Improved Glaser-Eglinton-Hayes Coupling
  • Modifications
    • Ethanol (95%) with TMEDA
    • Simplified isolation procedure
  • Benefits:
    • Reduced amount of solvent for isolation
    • Reduced amount of aqueous waste
    • Homogenous reaction
    • Stunning color change (light green to midnight blue by completion)
    • Reaction time: 40-60 min at room temperature (heating noted w/other procedures)*
    • Generally cleaner product in comparable yields

This reaction can also be run in 75% ethanol 50% ethanol 25% ethanol

Ken Doxsee, Jim Hutchinson, Green Organic Chemistry, Thompson Learning Custom Publ., Mason, OH, 2002, pp 143-152.

Charles Wilcox, Jr. and Mary Wilcox, Experimental Organic Chemistry, 2nd Ed., Prentice-Hall Publ. Englewood Cliffs, NJ, 1995. pp 349-352

improved glaser eglinton hayes coupling16
Improved Glaser-Eglinton-Hayes Coupling
  • Modifications
    • Ethanol (95%) with TMEDA
    • Simplified isolation procedure
  • Benefits:
    • Reduced amount of solvent for isolation
    • Reduced amount of aqueous waste
    • Homogenous reaction
    • Stunning color change (light green to midnight blue by completion)
    • Reaction time: 40-60 min at room temperature (heating noted w/other procedures)*
    • Generally cleaner product in comparable yields

This reaction can also be run

even in water!

Ken Doxsee, Jim Hutchinson, Green Organic Chemistry, Thompson Learning Custom Publ., Mason, OH, 2002, pp 143-152.

Charles Wilcox, Jr. and Mary Wilcox, Experimental Organic Chemistry, 2nd Ed., Prentice-Hall Publ. Englewood Cliffs, NJ, 1995. pp 349-352

experiment evaluation21
Experiment Evaluation
  • Experiment totals:
    • Methanol/pyridine = 11
    • Water/TMEDA = 6
new experiment candidate adipic acid synthesis
New Experiment Candidate: Adipic Acid Synthesis
  • Current experiment sequence:
  • Drawbacks:
    • Requires excess KMnO4 (3g /g ketone!)
    • Large quantities of MnO2 (oxidizer) produced (1.8g /g ketone)
    • Contaminated product (isolate by NaCl precipitation)
    • Low yields (ave 33% est. on last step; ave 20% overall)
new experiment catalytic oxidation a green adipic acid synthesis
New Experiment: Catalytic OxidationA Green Adipic Acid Synthesis
  • Propose1 – 1 g scale oxidation
  • Advantages
    • Catalytic oxidation
    • By-products: O2, H2O
    • Higher yields

1. Zhang, Shi-gang; Jiang, Heng; Gong, Hong; Sun, Zhao-lin Petroleum Science and Technology2003, 21 (1-2), 275-282.

experiment evaluation24
Experiment Evaluation
  • Scores:
    • KMnO4 method: 16
      • Includes KMnO4, NaOH, NaHSO3, celite
    • H2O2 method: 9
      • Includes H2O2, Na2WO4, sulfosalicylic acid
new experiment catalytic oxidation a green adipic acid synthesis25
New Experiment: Catalytic OxidationA Green Adipic Acid Synthesis
  • Reaction – 1 g scale oxidation
    • Heat: Steam bath, overnight
    • No residual peroxide
    • 75% average isolated yield of pure adipic acid from cyclohexanone
co catalysts
Co-catalysts
  • Sulfosalicylic acid (23 mg)
    • Best yields – ave 75%
    • Cleanest product
    • Very water soluble
  • Sodium bisulfate (30 mg)
    • Reduced yields (by ~ 60%)
    • Discolored product
    • Narrowed reaction time
  • Ascorbic acid (40 mg)
    • Reduced yields (~ 30%)
    • Discolored product

Ligand can be neutralized and sewered

slide27
7.5 mL

5 mL

15 mL

new experiment catalytic oxidation a green adipic acid synthesis28
New Experiment: Catalytic OxidationA Green Adipic Acid Synthesis
  • Reaction – 1 g scale oxidation
    • But, synthetic cyclohexanone sometimes gave poorer yields…
side reaction responsible for low yields
Side reaction responsible for low yields
  • According to procedure:
  • Analysis by GC and GCMS indicates
    • Vigorous reaction gives 2-chlorocyclohexanone
    • High amounts correlate with poor yields of adipic acid
catalytic oxidation a green adipic acid synthesis
Catalytic Oxidation:A Green Adipic Acid Synthesis
  • Proposed reaction pathway1

1. Based upon the work of Noyori and Fischer: Sato, K.; Aoki, M.; Noyori, R.; Science1998, 281, 1646. Fischer, J.; Holderich, W.F. Appl. Cat. A: General1999, 180, 435.

s n 2 experiment candidate
SN2 Experiment Candidate
  • Synthesis of n-butyl bromide from n-butanol
    • Drawbacks:

Low yields on a small scale

Impure product

Odor problems

Use of concentrated sulfuric acid

    • Goals:

Develop new experiment that still teaches the SN2 reaction

High yields of pure product

Simple experiment suitable for a beginning 3 h lab

proposed s n 2 experiment
Proposed SN2 Experiment

Use of PCl5

  • Proposed reaction scheme
  • Potential Advantages

Solventless reaction

One step

Short reaction time

Clean, high yield reaction

Introduce column chromatography for purification

experiment evaluation35
Experiment Evaluation
  • Scores:
    • NaBr/H2SO4 method: 18
      • Includes NaBr, H2SO4, H2O, NaHCO3, 1-butanol, 1-chlorobutane
    • PCl5 method: 14
      • Includes PCl5, pentane, H2O, NaHCO3, 1-tetradecanol, 1-chlorotetradecane (note: hexane score = 4)
synthesis of 1 chlorotetradecane from 1 tetradecanol
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
reaction mechanism is relevant
Reaction Mechanism is Relevant

Gerrard, W.; Phillips, R. J. Chemistry & Industry1952, 540-1.

reaction highlights
Reaction Highlights
  • Analyze by GC for purity but…

no need to introduce column chromatography!

  • IR, H & 13C NMR indicate high purity
reaction highlights39
Reaction Highlights
  • Combine solid reagents
reaction highlights40
Reaction Highlights

Mix with cooling

reaction highlights41
Reaction Highlights

Heat in steam bath

reaction highlights42
Reaction Highlights

Isolate by extraction

summary
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!
acknowledgements
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
new and improved green experiments for the organic chemistry lab46
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

[email protected]

July 30, 2006

Website: http://www.intech.mnsu.edu/groh

experimental procedures
Experimental Procedures

Procedures for the experiments outlined in this presentation may be requested from Brian Groh by email at [email protected] The experiments will be available in a photo-essay type format on my website hopefully by fall semester 2006. Follow the “LabViews” link on the home page.

Website: http://www.intech.mnsu.edu/groh

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