Ball Milling - University of Massachusetts Boston - a student
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Ball Milling An efficient and ecologically friendly synthetic approach ‐‐‐ Jackie Ding
Transcript of Ball Milling - University of Massachusetts Boston - a student
Ball Milling An efficient and ecologically friendly synthetic approach
‐‐‐ Jackie Ding
Ball milling – solvent free approach
Application in organic synthesis
Conclusion
Content
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The 12 Principles of Green Chemistry
Prevention of waste
Atom Economy
Less Hazardous Chemical Syntheses
Design Safer Chemicals
Safer Solvents and Auxiliaries
Design for Energy Efficiency
Reduce Derivatives
Use Renewable Feedstocks
Catalysis
Design for Degradation
Real-time Analysis for Pollution Prevention
Inherently Safer Chemistry for Accident Prevention
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Do I need to use a solvent?
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The best solvent is no solvent
Alternative solvents: water supercritical CO2 ionic liquids
Solventless Chemistry Mortar and pestle Ball milling
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Principles of green chemistry
Application in organic synthesis
Conclusion
Content
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What is ball milling? A ball mill is a type of grinder used to grind materials
into extremely fine powder.
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Major parameters for ball milling
Temperature
Size and Number of the balls
Nature of the balls
Rotation speed
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Types of Ball Mills
Drum ball mills Jet-mills Bead-mills Horizontal rotary ball mills Vibration ball mills Planetary ball mills
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Vibration Mills
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Mixer Mill MM 400
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Feed material: hard, medium-hard, soft, brittle, elastic, fibrous Material feed size: ≤ 8 mm Final fineness: ~ 5 µm Setting of vibrational frequency: digital, 3 - 30 Hz (180 - 1800 min-1)
Planetary Mills
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Planetary Ball Mill PM 400
Feed material: soft, hard, brittle, fibrous (dry or wet); Material feed size: < 10 mm; Final fineness < 1 µm; No. of grinding stations: 4 / 2
Principles of green chemistry
Ball milling – solvent free approach
Conclusion
Content
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Application in Organic Synthesis
Aldol Condensations Knoevenagel Condensations Baylis-Hillman Reaction Michael Reaction Wittig Reaction Fullerene Cycloadditions Suzuki Reaction Heck-Jeffery Reaction Radical Additions Mediated by Mn (III) Etc.
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Suzuki reaction
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B(OH)2 + Br-Ar
[Pd(PPh3)4] (5mol%)
K2CO3!(3 equivs.)
NaCl
ball milling
30-60 min
Ar
S. F. Nielsen, O. Axelsson, Synth. Commun. 2000, 30, 3501.
B(OH)2
+
Br
Ac
KF-Al2O3/ Pd(OAc)2
ball milling
Ar Ac
Franziska Schneider, Org. Proc. Res. & Develop., 2009, 13,44
Up to 96% yield
Entry Rpm T (min) Yield% 1 400 10 92 2 800 5 94
Aldol Condensation
17 B. Rodr´ıguez, Angew. Chem., Int. Ed., 2006, 45, 6924
O
+
H
O
R
(S)-proline10 mol%
Ball milling (A)or stirring (B)
O OH
R
Entry R= Method t/h Yield% anti/syn ee% 1 4-NO2 A 5.5 99 89:11 94 2 4-NO2 B 24 95 89:11 94 3 3-NO2 A 7 94 88:12 >99 4 3-NO2 B 16 89 82:18 98 5 2-NO2 A 7 97 93:7 97 6 2-NO2 B 36 89 91:9 97
Oxidation
18 Guan-Wu Wang, J. Org. Chem. 73, 7088 (2008).
Conventional heating in organic solvent: a. Acetic acid, 80oC, argon atmosphere, yield 32% b. Ethanol, refluxing temperature for 12h, yield 48%
O
OR1
R1
X
N
+R2
O
Mn(OAc)3.2H2O
ball milling
18 examples up to 91% yield
X
N
O
O
O
R1
R1
R2
X=CH or NR1= CH3
R2 = -C6H5, -C6H5NO2,
-C6H5CN, etc.
30Hz, 1h
Other applications of ball milling
Fine particles
Inorganic solids
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Drawbacks of ball milling
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• Solution Purification of
byproducts
• Solution It is not a magic wand.
Benign Solvents
Under development
Conclusion
Ball milling should be considered as a potentially attractive solution for solvent-free synthesis.
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Solvent free One-pot process
Tip of iceberg
Reference Lance Frazer, Environmental health perspectives, 2003, 111, 10 Belen Rodríguez, Adv. Synth. Catal. 2007, 349, 2213 Ana Lazuen Garay, Chem. Soc. Rev., 2007, 36, 846–855 Raphael Janot, Progress in Materials Science 50 (2005) 1–92 Andreas Theisen, “Green Chemistry”in the Laboratory, TECHNICAL
REPORT, www.retsch.com G Kaupp, Solvent-free organic synthesis, Wiley-VCH, 2009. S. F. Nielsen, O. Axelsson, Synth. Commun. 2000, 30, 3501. Franziska Schneider, Org. Proc. Res. & Develop., 2009, 13,44 B. Rodr´ıguez, Angew. Chem., Int. Ed., 2006, 45, 6924 Guan-Wu Wang, J. Org. Chem. 73, 7088 (2008). G.Kaupp, Top. Curr. Chem. 254, 95 (2005). M. Reza Naimi-Jamal, Eur. J. Org. Chem. 2009, 3567–3572.
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