presentation on Ultrasound In organic reaction and Supercritical Liquids

1. WELCOME
Ultrasound In organic reaction
 Supercritical Liquids
Microwave heating
Uses of enzymes in organic reaction
Prepared by
AL MAMUN
13024508
M.Sc(2016-17)
University of Rajshahi
Haimanti shokla paul
13224512
M.Sc(2016-17)
University of Rajshahi

2. What is ultrasound?
Ultrasound is defined by the American National Standards
Institute as "sound at frequencies greater than 20 kHz."
Ultrasound is sound waves with frequencies higher than the
upper audible limit of human hearing.
Ultrasound is no different from 'normal' (audible) sound in
its physical properties, except in that humans cannot hear
it.
Ultrasound In organic
reaction

3. Galton whistle, one of the first
devices to produce ultrasound
Ultrasound image of a fetus in
the womb
A dog whistle Bats use ultrasounds to navigate
in the darkness

4. The ultrasound irradiation (also referred to as sonochemistry)
is an important tool in the field of organic chemistry.
This technique has become extremely popular in promoting
various chemical reactions since the decade 1990–1999.
The application of ultrasound has been useful in accelerating
dissolution, enhancing the reaction rates, and renewing the
surface of a solid reactant or catalyst in a variety of reaction
systems.

5. In recent years, the effect of ultrasonic energies in organic
synthesis (homogeneous and heterogeneous reactions) has
widely increased.

6. Two of the most important advantages in the use of
sonochemistry in organic synthesis:
 increase of reaction rates
 Increase of product yields
So this methodology is more convenient when compared with
the traditional method, and it can be easily controlled.
For Heterocycles
Heterocycles are one of the most popular and important organic
compounds because they are involved in many fields of science.

7. agricultural, industrial, medicinal chemistry, and material science.
good alternative technique to synthesize both heterocycles
and fused heterocycles with short reaction times, high
yields, lower costs and mild conditions.
2-amino-2-chromenes 2,4,5-Triarylimidazole 1-Acylbenzotriazoles

8. Used as alternative energy source in the area of green and
pharmaceutical chemistry.

9. Reactions that are found to be improved under
sonication:
1.Condensation 6. Substitution
2.Oxidation 7. Reduction
3.Addition 8. Protection/deprotection
4. Coupling 9. Photochemical
5.Polymerization

10. Heterocyclic compound
Synthesis of Aminopyrazoles:
Mara E. F. Braibante et al. conveniently prepared 5(3)-
Amino3(5) phenylpyrazoles by condensation of alpha-
oxoketene O,N-acetals with hydrazine under sonication.

11. Condensation reaction
Synthesis of hydroxyl ketones:
Ji-Tai Li et al. synthesized hydroxyl ketones in the
presence of trisodium phosphate via cross-aldol reactions of
reactive aldehydes with substituted acetophenone in
methanol-water mixed solvent in good to excellent yields
under ultrasound irradiation.

12. Substitution reaction
Synthesis of Trimethylsilyl Pseudohalides:
Xu Yongshen et al. prepared conveniently Trimethylsilyl
pseudohalides Me3SiX, where X = NCS, NCO, or CN, in
desirable yields by the reaction of Me3SiCl with NaX or KX
catalyzed by PEG400 and zinc iodide under ultrasound
irradiation.
Me3SiCl + MX Me3SiX + MCl
CH2Cl2, ))))
PEG400/ZnI2
M = Na or K, X= NCS, NCO, CN

13. Photochemical reaction
Synthesis 1-Iodocyclohexene:
A rapid formation of radical product was accompanied by
substantial decrease of 1-iodocyclohexene after application
of ultrasound and irradiation without the zinc.The
sonochemical stirring is more effective than mechanical
stirring.

14. Some other reaction improved by ultrasound

15. Supercritical Liquids
A supercritical fluid (SCF) is any substance at
a temperature and pressure above its critical point, where
distinct liquid and gas phases do not exist.
It can effuse through solids like a gas, and dissolve materials like
a liquid.
In 1822, Baron Charles Cagniard de la Tour discovered the
critical point of a substance in his famous cannon barrel
experiments.

16. Carbon dioxide and water are the most commonly used
supercritical fluids, being used for decaffeination and power
generation, respectively.
Supercritical fluids are suitable as a substitute for organic solvents in
a range of industrial and laboratory processes.

17. Phase diagram

18. Properties
There is no surface tension in a supercritical fluid, as there is
no liquid/gas phase boundary.
 Changing the pressure and temperature of the fluid, the
properties can be "tuned" to be more liquid-like or more gas-
like.
 Most important properties is the solubility of material in the
fluid.
 At constant density, solubility will increase with temperature
and pressure.

20. Uses
• Supercritical fluid chromatography
• Supercritical fluid extraction
• Dry-cleaning
• Chemical reactions
• Generation of pharmaceutical cocrystals
• Nano and micro particle formation
• Supercritical fluid in power generation
• Biodiesel production

21. • Enhanced oil recovery and carbon capture and
storage
• Enhanced geothermal system
• Antimicrobial properties
I will discuss those elaborately

22. Supercritical fluid extraction
The advantages of supercritical fluid extraction (compared with liquid extraction) are that it is
relatively rapid because of the low viscosities and high diffusivities associated with
fluids.
Dry-cleaning
Supercritical carbon dioxide (SCD) can be used instead of PERC (perchloroethylene) or other
undesirable solvents for dry-cleaning. Supercritical carbon dioxide sometimes intercalates
into buttons, and, when the SCD is depressurized, the buttons pop, or break apart.
Detergents that are soluble in carbon dioxide improve the solvating power of the solvent
Supercritical fluid chromatography
Supercritical fluid chromatography (SFC) can be used on an analytical scale, where it
combines many of the advantages of high performance liquid chromatography (HPLC) and
gas chromatography (GC). It can be used with non-volatile and thermally labile analytes
(unlike GC) and can be used with the universal flame ionization detector (unlike HPLC), as
well as producing narrower peaks due to rapid diffusion.
Chemical reactions
Changing the conditions of the reaction solvent can allow separation of phases for product
removal, or single phase for reaction. Rapid diffusion accelerates diffusion controlled
reactions. Temperature and pressure can tune the reaction down preferred pathways, e.g., to
improve yield of a particular chiral isomer.

23. Biodiesel production
Conversion of vegetable oil to biodiesel is via a transesterification reaction, where the
triglyceride is converted to the methyl ester plus glycerol. This is usually done using
and caustic or acid catalysts, but can be achieved using supercritical methanol without a
catalyst.
Antimicrobial properties
CO2 at high pressures has antimicrobial properties.[35] While its effectiveness has been
shown for various applications, the mechanisms of inactivation have not been fully
understood although they have been investigated for more than 60 years.