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Green Chemistry: Microwave Assisted Organometallic Reaction. Green Chemistry. To promote innovative chemical technologies that reduce or eliminate the use or generation of hazardous substances in the design, manufacture, and use of chemical products. What does the Chemical Industry do for us?.
To promote innovative chemical technologies that reduce or eliminate the use or generation of hazardous substances in the design, manufacture, and use of chemical products.
Why is there no ‘Green Geology’ or ‘Green Astronomy’?
Because chemistry is the science that introduces new substances into the world and we have a responsibility for their impact in the world.”
- Ronald Breslow
The British were particularly forward-looking in deploying radar for air defense with a system called Chain Home which began operation in 1937.
Originally operating at 22 MHz, frequencies increased to 55 MHz.
1921 was published by A.W. Hull the earliest description of the magnetron, a diode with a cylindrical anode
1940 It was developed practically by Randall and Booth at the University of Birmingham in England ; they verified their first microwave transmissions: 500 W at 3 GHz.
A prototype was brought to the United States in September of that year to define an agreement whereby United States industrial capability would undertake the development of microwave radar.
1940 the Radiation Laboratory was established at the Massachusetts Institute of Technology to exploit microwave radar. More than 40 types of tube would be produced, particularly in the S-band (i.e. 300 MHz). The growth of microwave radar is linked with Raytheon Company and P.L. Spencer who found the key to mass production.
Three ways to get the reaction done, but different energy bills to pay
Neas, E.; Collins, M. Introduction to Microwave Sample Preparation: Theory and Practice, 1988, p. 8.
E= electric field
H= magnetic field
l= wavelength (12.2 cm for 2450 MHz)
c= speed of light (300,000 km/s)
1946: Original patent (P. L. Spencer)
1947: First commercial oven
1955: Home models
1967: Desktop model
1975: U.S. sales exceed gas ranges
1976: 60% of U.S. households have
rates of 10 °C per second when powerful waves are used
Alternating electric field
Dipolar molecules try to
align to an oscillating field
Ions in solution will move
by the applied electric
Mingos, D. M. P. et al., Chem. Soc. Rev. 1991, 20, 1 and 1998, 27, 213
J.-S. Schanche, Mol. Diversity 2003, 7, 293.
temperature on the outside surface is
in excess of the boiling point of liquid
Inverted temperature gradients!
Cooking Chemistry ???
Household MW ovens
The Use of Microwave Ovens for Rapid Organic Synthesis R. Gedye et al., Tetrahedron Lett. 1986, 27, 279.
7 Synthetic Journals: J.Org.Chem.,Org.Lett.,Tetrahedron Lett.,Tetrahedron, Synth.Commun., Synlett, Synthesis
All Journals (Full Text): Dedicated instruments only (Anton Paar, Biotage, CEM, Milestone, Prolabo)
+ Drying / roasting / baking
+ Sewage treatment
+ Wood, fibers, textiles
+ Brick / concrete walls
+ Rubber curing, vulcanization
Biochemistry / Pathology
+ Protein hydrolysis
+ PCR, proteomics
+ Tissue fixation
+ Alumina sintering
+ Welding, smelting, gluing
+ Diathermy, tumor detection
+ Blood warming
+ Sterilization (Anthrax)
+ Drying of catheters
(ACS Professional Reference Book) H. M. Kingston, S. J. Haswell (eds.)
Hayes, B. L.,
Microwaves in Organic and Medicinal Chemistry
Kappe, C. O. and Stadler, A.
Wiley-VCH, Weinheim, 2005, ISBN: 3-527-31210-2
410 pages, ca 1000 references,
Fundamentals of Microwave Application
Alternative Laboratory Microwave
Laboratory Microwave Safety
Tierney, J. P.
Loupy Andre (Ed.)
Wiley-VCH, Weinheim, 2003, ISBN: 3-527-30514-9
523 pages, 2000 refs.
Book (2 volumes) Wiley-VCHA.
(2006) 22 Chapters
Practical Microwave Synthesis for Organic Chemists - Strategies, Instruments, and Protocols
Edition - 2009, X, 310 Pages, Hardcover, Monograph
Astra Zeneca Research
Foundation Kavitha Printers,
Bangalore, India, 2002
Piccoli volumi processabili
- Onde Stazionarie (Hot Spots)
- Difficoltà nello Scale-up
+ Alta densità d’energia
Images adapted from: C.O. Kappe, A. Stadler: Microwaves in Organic and Medicinal Chemistry, Wiley, 2005
+ Alta densità d’energia (maggior potenza disponibile)
+ Maggiori volumi processabili (cavità a MW più grande)
+ No Onde Stazionarie (No Hot-spots)
+ Semplice Scale-up
- Volume minimo processabile
R. Gedye, F. Smith, K. Westaway, H. Ali, L. Baldisera, L. Laberge, J. Rousell, Tetrahedron Lett. 1986, 27, 279–282. R. J. Giguere, T. L. Bray, S. M. Duncan,
G. Majetich, Tetrahedron Lett. 1986, 27, 4945–4958.
thermal: 1 h, 90 % yield (reflux)
MW: 10 min, 99 % yield (sealed vessel)
The first reports on the use of microwave heating to accelerate organic chemical transformations (MAOS) were published by the groups of Richard Gedye (and Raymond J. Giguere/George Majetich in 1986. In those early days, experiments were typically carried out in sealed Teflon or glass vessels in a domestic household microwave oven without any temperature or pressure measurements. The results were often violent explosions due to the rapid uncontrolled heating of organic solvents under closed-vessel conditions.
“No reaction proceeds without solvent”
Chemical Synthesis w i t h o u t t h e u s e o f solvents has developed
i n t o a p o w e r f u l
m e t h o d o l o g y a s i t reduces the amount of toxic waste produced and therefore becomes less harmful to the
e n v i r o n m e n t
Best solvent is no solvent!
G. W. V. Cave, C. L.
Raston, J. L. Scott
R. S. Varma and K. P. Naiker, Org. Letters, 1999, 1, 189.
Kumar, Chandra Sekhar, Dhillon, Rao, and Varma,Green Chem., 2004, 6, 156-157.
Kumar, Sundaree, Rao and Varma,Tetrahedron Letters, 2006, 47, 4197-4199.
F. Toda et al. Angew. Chem. Int. Ed. Engl., 1989, 28, 320and Chem. Commun., 1989, 1245.
Toda, Tanada, Iwata, J. Org. Chem., 1989, 54, 3007.
Y. Ito, S. Endo, J. Am. Chem. Soc. 1997, 119, 5974.
Shin, Keating, Maribay, J. Am. Chem. Soc. 1996, 118, 7626.
Z. Gross, et al., Org. Letters, 1999, 1, 599.
Wang, Komatsu, Murata, Shiro, Nature 1997, 387, 583
R. S. Varma, Tetrahedron, 2002, 58, 1235.
R. S. Varma, Green Chem., 1999, 1, 43.
E. Gutterrez, A. Loupy, G. Bram, E. Ruiz-Hitzky, Tetrahedron Lett. 1989, 30, 945.
Varma et al.: J. Chem. Soc., Perkin Trans. 1, 999 (1993)
A practical alternative to traditional catalytic hydrogenation
Varma et al.: Tetrahedron Lett., 34, 4603 (1993)
Varma, Meshram: Tetrahedron Lett., 38, 5427 (1997)
Varma, Meshram: Tetrahedron Lett., 38, 7973 (1997)
Varma et al., Tetrahedron Lett., 1997, 38, 2043 and 7823
Chemoselective reduction of trans-cinnamaldehyde: olefinic moiety remains intact and the aldehyde functionality is reduced in a facile reaction.
Varma et al., Tetrahedron Lett., 1997, 38, 4337
Pillai, Sahle-Demessie, Varma: Green Chemistry, 6, 295 (2004)
Varma et al.: J. Chem. Soc. Perkin Trans 1, 4093 (1998)
Varma, J. Heterocycl. Chem., 36, 1565 (1999)
Strong fluorescent properties
U. Bora, A. Saikia, R. C. Boruah – Organic Lett., 5 (4), 435, 2003;
Asymmetric indolizines, by irradiation with microwaves, in MCR
A. Rotaru, I. Druţă, T. Oeser, T. Muller – Helv. Chim. Acta, 88, 1798, 2005;
Reaction conditions and the yelds for synthesized compounds (12a-d)
Ju, Li and Varma, QSAR & Combinatorial Science, 2004, 23, 891
Varma, Namboodiri, Chem. Commun., 2001, 643.
Varma, Namboodiri, Pure Appl. Chem., 2001, 73, 1307.
Namboodiri, Varma, Chem. Commun., 2002, 342.
Kim and Varma. J. Org. Chem., 2005, 70, 7882.
J. Chen, S. K. Spear, J. G. Huddleston, R.D. Rogers, Green Chem.. 2005, 7, 64.
V. Namboodiri, R. S. Varma: Green Chemistry, 2001, 3, 146.
P. Appukkuttan, W. Dehaen, V. V. Fokin, E. Van der Eycken.
Org. Lett. 2004, 6, 4223.
Ju, Y.; Varma, R. S., Green Chem. 2004, 6, 219-221.
Ju, Y.; Varma, R. S., Green Chem. 2004, 6, 219-221.
Ju; Varma, Tetrahedron. Lett., 2005, 46, 6011.
Ju; Varma, J. Org. Chem., 2006, 71, 135.
Green chemistryNot a solution to all environmental problems But the most fundamental approach to preventing pollution.
A. Loupy, A. Petit, J. Hamelin, F. Texier- Boullet, P. Jacquault, D. Math_, Synthesis1998, 1213–1234; R. S. Varma, Green Chem. 1999, 43–55; M. Kidawi, Pure Appl. Chem. 2001, 73, 147–151; R. S. Varma, Pure Appl. Chem. 2001, 73, 193–198; R. S. Varma, Tetrahedron 2002, 58, 1235–1255; R. S. Varma, Advances in Green Chemistry: Chemical Syntheses Using Microwave Irradiation, Kavitha Printers, Bangalore, 2002. A. K. Bose, B. K. Banik, N. Lavlinskaia, M. Jayaraman, M. S. Manhas, Chemtech 1997, 27, 18–24; A. K. Bose, M. S. Manhas, S. N. Ganguly, A. H. Sharma, B. K. Banik, Synthesis 2002, 1578–1591. C. R. Strauss, R. W. Trainor, Aust. J. Chem. 1995, 48, 1665–1692; C. R. Strauss, Aust. J. Chem. 1999, 52, 83–96; C. R. Strauss,
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