Methodical Instruction for Students of the 2 Course pharmaceutical Faculty
LESSON № 12 (PRACTICAL – 6 HOURS)
Themes: 1. Aldehydes and ketones of the aliphatic row. Small practicum.
2. Aldehydes and ketones of the aromatic row. Small practicum.
Aim: To learn: the nomenclature, isomerism, methods of extraction, physical and chemical properties of aldehydes and ketones.
Professional orientation of students.
Adehyde – а carbonyl compound containing two hydrogen atoms or hydrogen and alkyl group.
Ketone – а carbonyl compound containing а pair of cumulative double bonds of which one is the carbonyl group, or ketone is а carbonyl compound containing two alkyl groups.
Traditionally, aldehyde names were derived from the name of the corresponding acid by dropping the suffix –ic (or – oic) and adding in its place the suffix – aldehyde. These commoames are still widely used for simpler aldehydes.
The commoames of ketones are derived by prefixing the word ketone by they names of the two alkyl-radical-groups; the separate parts are separate words.
Methodology of Practical Class (900-1200).
Experiment 1. Color reactions on aldehydes.
Reagents: formaldehyde (10% solution), acetic aldehyde (10% solution), fuchsine sulfite acid, concentrated HCl, resorcinol (5% solution), concentrated H2SO4, sodium nitroprusside (0,5% solution), piperidine.
Technique of experiment.
a) the reaction of aldehydes with fuchsine sulfite acid. In 2 test-tubes bring 1 ml fuchsine sulfite acid. In the first test-tube add 5 drops of formaldehyde (10% solution), in the second test-tube add 5 drops of acetic aldehyde (10% solution). Put the test-tubes in a support. After some time the solution in the first test-tube becomes violet, and the solution in the second test-tube becomes pink-violet. Then add 0,5 ml of concentrated HCl in each test-tube. After some time the solution inthe first test-tube becomes violet-blue, and the color of solution in the second test-tube disappears.
Dye fuchsine is the derivative of triphenylmethane. It has the next structure.
Fuchsine has red-violet color because of conjugated double bounds system, which includes quinoide group of atoms. As the result of reaction of fuchsine with sulfur (IV) oxide the color of solution disappears because fuchsine sulfite acid forms (it is colorless, because quinoide group is absent in its structure).
Aldehydes connect with fuchsine sulfite acid and form compounds, which have quinoide group in their structure. That is why they have color which is similar to the color of fuchsine.
Products of aldehydes accession to fuchsine sulfite acid gradually interact with sulfur (ІV) oxide, which always contents in fuchsine sulfite acid solution in excess. As a result the compound and fuchsine sulfite acid form. That is why the mixture becomes colorless. Excess of mineral acids decomposes color products of aldehydes accession to fuchsine sulfite acid. If to the color mixture add chloride or sulfate acid, violet color disappears (except formaldehyde, which keepscoloration in the presence of strong acids). The solution with formaldehyde becomes blue. This reaction can distinguish formaldehyde from other aldehydes in the mixture. Reaction with fuchsine sulfite acid is very sensitive and character for aldehydes. Ketones, as a rule, do not give this reaction.
b) color reaction of formaldehyde with resorcinol. Bring in a test-tube 2 ml of resorcinol (5% solution) and add 1 ml of 10% formaldehyde solution. Add 2 ml of concentrated H2SO4 by drops. Look after acid does not mix with the mixture. The pink ring appears.
c) color reaction of acetic aldehyde with sodium nitroprusside. In a test-tube bring 5 ml of sodium nitroprusside (0,5% solution), add 0,3 ml of acetic aldehyde and 0,2 ml of piperidine. Mix the mixture. The dark-blue color appears. This reaction is qualitative on aldehydes. Sodium nitroprusside gives color reaction with thesimplest ketones.
Experiment 2. Extraction of formic aldehyde.
Reagents: methyl alcohol, fuchsine sulfite acid.
Technique of experiment. Bring 2-3 ml of methyl alcohol in a test-tube. Heat the copper wire in a flame and quickly deep in methyl alcohol. Close the test-tube by cork. Reduction of cooper oxide to metallic cooper takes place. Repeat this operation several times. Determine aldehyde by the smell and reaction with fuchsine sulfite acid. Write the equation of reaction.
Experiment 3. Oxidation of ethyl alcohol by K2Cr2O7.
Reagents: ethyl alcohol, fuchsine sulfite acid, K2Cr2O7, H2SO4 (10% solution).
Technique of experiment. Bring 0,5 g of K2Cr2O7 in a test-tube and add 2 ml of H2SO4 (10% solution). Mixing the mixture add 2 ml of ethyl alcohol by drops. The mixture becomes hot and the color of it changes. Close the test-tube by cork with gas-pipeline. Deep the end of gas-pipeline into the test-tube with 2 ml of cooled distil water. Fasten the test-tube with reaction mixture on a support and cool the receiving tube with ice water. Carefully heat the mixture. As a result, acetic aldehyde evaporates and solves in cooled distil water in a receiving test-tube. Distillation of aldehyde is continued during 2-3 minutes.
Investigate the obtained acetic aldehyde solution on the presence of aldehyde. For this to 1 ml of fuchsine sulfite acid add 1 ml of received aqueous solution ofacetic aldehyde. Observe that solution of fuchsine sulfite acid paints in pink-purple color. Keep the solution of acetic aldehyde for the next experiments.
Write the equations of reactions.
Experiment 4. Extraction of glycerin aldehyde by the oxidation of glycerin with chromic mixture.
Reagents: glycerin, K2Cr2O7 (10% solution), H2SO4 (10% solution), fuchsine sulfite acid.
Technique of experiment. Bring 1 ml of K2Cr2O7 (10% solution) in a test-tube, 1 ml of H2SO4 (10% solution) and 1 ml of glycerin. Shake the mixture and close it by a cork with gas-pipeline tube. Deep the end of gas-pipeline into the test-tube with 2 ml of fuchsine sulfite acid. Heat the mixture.
What do you see? Explain the answer.
Experiment 5. Obtaining of acetone by calcium acetate pyrolysis.
Reagents: anhydrous calcium acetate.
Equipment: devise for the acetone obtaining.
Technique of experiment. Bring to the dry test-tube dry calcium acetate, which must be takeot less then forth part of the tube’s volume. Close the test-tube by a cork with a gas-pipeline tube. Distribute calcium acetate along the test-tube; fasten this tube on a support (look figure 1). You must do this because tube may crack when water from the not complete fried calcium acetate will get on the walls of test-tube.
End of the gas-pipeline tube deep in the receiving tube, which contains 2-3 ml of water. Heat calcium acetate in the flame of burner. During pyrolysis acetone forms, which dissolves in water in the receiving tube. Volume of the liquid in receiving tube increases in twice after 5 minutes. Write the reaction equation.
Keep the water solution of acetone for the next experiments.
Experiment 6. Extraction of iodoform from acetone.
Reagents: acetone, crystal iodine, NaOH (10% solution).
Technique of experiment. Bring 1 ml of acetone in a test-tube, and then add powder of iodine. Mixing the mixture add NaOH(10% solution) by drops to the disappearing of the color of iodine. Yellow precipitate forms. It is iodoform with peculiar smell.
This reaction is called iodoform test on acetone. Iodoform test is very sensitive.
Experiment 7. The color reaction on acetone.
Reagents: acetone, sodium nitroprusside (10% fresh solution), concentrated acetic acid solution, NaOH (10% solution).
Technique of experiment. Bring 1 ml of water in a test-tube, then add 1-2 drops of sodium nitroprusside (10% fresh solution), 1-2 drops of acetone and 1-2 drops of NaOH (10% solution). The mixture becomes dark-red, then orange. Add several drops of concentrated acetic acid. The mixture becomes deep pink.
This test is used in clinic laboratories to determine the presence of acetone in urine (diabetic disease).
Experiment 8. The oxidation of aldehydes by the ammonium solution of silver nitrate (reaction of “silver mirror”).
Reagents: formalin (40% solution), acrolein (water solution), acetone, AgNO3 (1% solution), NH4OH (5% solution), NaOH (10% solution).
Technique of experiment. For the obtaining of “silver mirror” at first wash the tubes. For this in the test-tubes boil (Carefully!) 10 % sodium hydroxide solution during 1-2 minutes (portions by 5 ml). For the uniform boiling put in the alkali solution few boiling stones. Then wash the tubes by distill water. In each test-tubes bring 1 ml of AgNO3 (1% solution) and add NH4OH (5% solution) by drops to the disappearing of precipitate. In the first test-tube add 0,5-1 ml of formalin (40% solution), in the second test-tube add 0,5-1 ml of acrolein (water solution), in the third test-tube add 0,5-1 ml of acetone. Heat it in boiling water.
What do you see? Write the equations of reactions.
This reaction is qualitative to aldehydes.
Experiment 9. The oxidation of aldehydes by cooper (II) hydroxide (Trommer’s reaction).
Reagents: formalin (40% solution), acrolein (water solution), CuSO4 (2% solution), NaOH (10% solution).
Technique of experiment. Bring 1 ml of CuSO4 (2% solution) in 2 test-tubes and add NaOH (10% solution). The precipitate forms. In the first test-tube add 0,5-1 ml of formalin (40% solution), in the second test-tube add 0,5-1 ml of acrolein (water solution). Shake the mixtures and heat only in the upper part of the mixtures (lower parts must be cool). In heated parts of mixtures the precipitate becomes yellow (CuOH), and then red (Cu2O). This reaction is qualitative on aldehydes.
Write the equations of reactions.
Experiment 10. Interaction of acetic aldehyde and acetone with sodium hydrosulfite.
Reagents: 50% solution of acetic aldehyde, acetone, saturated solution of sodium hydrosulfite, 10% solution of chloride acid, 10% sodium carbonate solution.
Equipment: glass with ice.
Technique of experiment. Experiment is conducted in two test-tubes. Bring in each test-tubes 3 ml of the saturated sodium hydrosulfite solution. Shake thetubes; in one tube add 1 ml of acetic aldehyde (obtained in experiment 3), in the second tube add 1 ml of acetone. Heat the reaction mixtures and cool in the glass with ice. Observe formation of the white crystalline sediments of acetic aldehyde and acetone hydrosulfite derivatives.
Filtrate crystals of acetic aldehyde and acetone hydrosulfite derivatives and note that they don’t have smell character for acetic aldehyde and acetone.
Bring acetone hydrosulfite derivative in two test-tubes. To the one tube add 1 ml of 10 % chloride acid solution, to the second – 1 ml of 10% sodium carbonate solution. Observe the dissolution of the crystals of hydrosulfite derivatives. Heat the reaction mixtures and determine the smell of pairs. Fill the character smell ofacetone. So, aldehyde and ketone hydrosulfite derivatives decompose by the solutions of acids.
Experiment 11. The reaction of acetic aldehyde with 2,4-dinitrophenylhydrasine.
Reagents: acetic aldehyde (20% solution), acetone (20% solution), 2,4-dinitrophenylhydrasine (solution in concentrated H2SO4).
Technique of experiment. Bring 1 ml of 2,4-dinitrophenylhydrasine in 2 test-tubes. In the first test-tube add 1 ml of acetic aldehyde (20% solution), in the second test-tube add 1 ml of acetone (20% solution). Shake the mixtures and wait. After some minutes the orange precipitate forms.
Experiment 12. The reaction of acetone with hydroxylamine.
Reagents: acetone, hydroxylamine, Na2CO3.
Technique of experiment. Bring 0,5 g of hydroxylamine in a test-tubes and add 1 ml of water. Then add Na2CO3 to stopping of gas evaporation. Cool the test-tube and during the mixing add 5 ml of acetone. The crystals appear (oximes).
Experiment 13. The reaction of albumen with formalin.
Reagents: albumen, formalin.
Technique of experiment. Bring 1 ml of solution of albumen in test-tubes and add 1 ml of formalin. The precipitate forms. Formalin destroys albumen.
Experiment 14. The extraction of paraform.
Reagents: formalin.
Technique of experiment. Bring 1 ml of 40% solution of formalin in a test-tube and cool the test-tube in ice. White precipitate forms.
Then heat it very carefully. The precipitate disappears.
Basic concepts of theme
Composition – Structure – Properties
Aldehyde group
Aldehydes
Carbonyl group
Ketones
Reduction
Oxidation
Substitution reactions
Nucleophillic accession reactions
Individual Students Program.
1. Classification, nomenclature and isomerism of aldehydes and ketones.
2. Laboratory methods of receiving of aldehydes and ketones.
3. Electronic structure of carbonyl group. Reaction centers in the molecules of aldehydes and ketones.
4. Chemical properties of aldehydes ketones.
a. Mechanism of the nucleophillic accession reactions (AN).
b. Accession of water, alcohols, sodium hydrosulfite, cyanohydrate, metal-organic compounds.
5. Mechanism of the accession-elimination reactions.
c. Role of the acidic and basic catalysis.
d. Obtaining of amines, oxides, hydrazones and semicarbazones.
e. Usage of the reactions of oxides and hydrazones formations in qualitative analysis.
6. Reactions by the participants of СН-acidic center.
f. Structure of the phenolate-ion.
g. Keto-enol tautomery.
h. Condensation of aldol and croton type.
7. Oxidation-reduction properties of aldehydes and ketones.
8. Distinct reactions of aldehydes from ketones.
9. Identification of aldehydes and ketones.
10. Some representatives and usage in medicine.
Seminar discussion of theoretical issues (1230 – 1400 hour).
Test evaluation and situational tasks.
Home task: 1, 2, 3.
1. Write the structural formulas of all isomeric aldehydes and ketones, of the following composition С4Н8О and name them by radical-functional, substitution andrational nomenclatures.
2. Write the structural formulas of the next compounds:
a. acetic aldehyde;
b. propanone;
c. isopropyl ketone;
d. 2-methoxibutanal;
e. 3,7-dimethyl-4-methoxyoctadiene-2;
f. acetyl-acetone.
3. Write the equations of reactions, which are used for the obtaining of propionic aldehyde and ethylmethyl ketone: а) oxidation of alcohol; b) dehydration of alcohol; c) from the calcium salts; d) from dihalogenderivatives; e) oxosynthesis from alkenes (hydroformilation); f) olefins ozonolysis; є) magnesium organic synthesis.
4. Give the characteristics of C=O and C=C bonds. What characteristics are different and what characteristics are similar?
5. Write the scheme of transformations of butyl chloride in butanone, propene in propanal.
6. Write the scheme of difficult ethereal condensation by Tishchenco for butanal and Cannizzaro reaction for the trimethylacetic aldehyde obtaining. Write the mechanisms of reactions.
7. What reactions can be used to distinguish butanal from butanone?
8. Write the schemes of reactions of butyric aldehyde with following reagents: а) CH3MgJ; b) LiAlH4; c) PCl5; d) H2N–OH; e) HCN. Name the products.
9. Obtain isopropylacetic aldehyde from the appropriate alcohol by the oxidation reaction. Show the oxidation-reduction process. What oxidant is used in this reaction?
10. Obtain complete acetal of propionic aldehyde from the propyl alcohol.
11. Write examples of the reactions of aldehydes and ketones in basic (alkali) and acidic mediums: а) aldol and croton condensations; b) Cannizzaro reaction; c)polymerization.
12. Now for the protection of carbonyl group formation of cyclic acetals are mainly used. Propose the way of glycerin aldehyde synthesis from propenal (acrolein), useethylene glycol for the protection of aldehyde group. Why it is not possible to conduct this process with acrolein?
13. Distinguish two compounds in the following pairs from each other by the usage of iodoform test and “silver mirror” reaction: 1) pentanal and pentanone-2; 2)pentanone-2 and pentanone-3. Write the schemes of the appropriate reactions.
14. Make the chemical transformations and name the products.
А) CHBr2-CH2-CH3 №1 №2 №3;
B) CH3-CH2CH(OH)-CH3 №1 №2;
C) СН3-ССН №1 №2 №3 №4;
D) С6Н5С(О)Н №1 №2 №3.
15. Compare the reaction ability of propanone and benzophenone in the reactions of nucleophillic accession. Write the scheme of interaction of propanone withphenylhydrazide. Describe the mechanism of reactions.
16. Write the scheme of interaction of ethanal with sodium hydrosulfite. Describe the mechanism of reaction.
17. Which of the following compounds – benzaldehyde, propanone, phenol, butanal – will give “silver mirror” reaction? Write the schemes of reactions.
18. Make the following transformations, name the products of reactions and write the mechanisms of reactions:
19. Compare the reaction ability of acetophenone and propanone in the reactions of nucleophillic accession. Write the scheme of interaction of propanone withsemicarbazide. Describe the mechanism of reactions.
20. Write the scheme of interaction of butanal with 2 mol of methanol. Describe the mechanism of reaction. Explain role of catalyst in this reaction.
21. Which of the following compounds – propanal, formic acid, butanone, benzaldehyde – will oxidize by copper (ІІ) hydroxide? Write the schemes of reactions. How does the color of solution change?
22. Compare the reaction ability of propanone and benzophenone in the reactions of nucleophillic accession. Write the scheme of interaction of benzaldehyde withethylamine. Describe the mechanism of reactions.
23. Compare the reaction ability of propanone and benzophenone in the reactions of nucleophillic accession. Write the scheme of interaction of benzaldehyde withmethylamine. Describe the mechanism of reactions.
24. Write the scheme of croton condensation of 3-methylbutanal in alkali medium. What reaction centers will take part in this reaction? Describe the mechanism.
25. Propose the scheme of synthesis of benzyl acetate with benzene.
26. Make the following transformations, name the products of reactions and write the mechanisms of reactions:
27. Write the scheme of propanal aldol condensation. Describe the mechanism. Which medium is necessary for this reaction?
28. Make the following transformations, name the products of reactions and write the mechanisms of reactions
29. Choose the proper names for the following compounds (make the accordance structure-name).
1.
2.
3.
4.
5.
A. m-aminobenzaldehyde
B. α-oxypropanoic aldehyde
C. p-tolualdehyde
D. 2,4-pentadienal
E. 2-bromo-3-hydroxibutanal
30. Which of the following reactions lead to the formation of benzaldehyde?
A.
B.
C.
D.
E.
31. Which reagent can be used to distinguish methanal from ethanal.
A. [Ag(NH3)2]OH
B. acid fuchsine sulphite
C. H2 (Ni)
D. NH3
E. NH2OH
32. What is the product of condensation of two molecules of benzaldehyde in the presence of cyanide-ions?
A.
B.
C.
D.
E.
33. Which of the following reactions leads to the formation of acetophenone?
A.
B.
C.
D.
E.
Correct answers of test evaluations and situational tasks:
29. 1-C, 2-B, 3-A, 4-E, 5-D.
30. B, D.
31. B.
32. B.
33. B.
Student should know:
– the structure, nomenclature, isomerism, methods of extraction and chemical properties of aldehydes and ketones.
Student should be able to:
– do the chemical reactions to aldehydes and ketones.
References:
Main:
1. Clayden Jonathan. Organic Chemistry. Jonathan Clayden, Nick Geeves, Stuart Warren // Paperback, 2nd Edition. – 2012. – 1234 p.
2. Bruice Paula Y. Organic Chemistry / Paula Y. Bruice // Hardcover, 6th Edition. – 2010. – 1440 p.
3. Brückner Reinhard. Organic Mechanisms – Reactions, Stereochemistry and Synthesis / Reinhard Brückner // Hardcover, First Edition. – 2010. – 856 p.
4. Moloney Mark G. Structure and Reactivity in Organic Chemistry / Mark G. Moloney // Softcover, First Edition. – 2008. – 306 p.
5. Carrea Giacomo. Organic Synthesis with Enzymes in Non-Aqueous Media / Giacomo Carrea, Sergio Riva // Hardcover, First Edition. – 2008. – 328 p.
6. Smith Michael B. March’s Advanced Organic Chemistry. Reactions, mechanisms, and structure / Michael B. Smith, Jerry March // Hardcover, 6th Edition. – 2007. – 2384 p.
7. Carey Francis A. Advanced Organic Chemistry / Francis A. Carey, Richard A. Sundberg // Paperback, 5th Edition. – 2007. – 1199 p.
8. http://intranet.tdmu.edu.ua/data/kafedra/internal/zag_him/classes_stud/pharmaceutical/pharmacy/full_time_study/organic_chemistry/2_course/lesson_12. Aldehydes and ketones of aliphatic and aromatic rows.
9. http://intranet.tdmu.edu.ua/data/kafedra/internal/zag_him/presentations/pharmaceutical/pharmacy/full_time_study/organic_chemistry/2_course/lecture_07. Aldehydes and ketones.
Additional:
1. Francotte Eric. Chirality in Drug Research / Eric Francotte, Wolfgang Lindner //
Hardcover, First Edition. – 2006. – 351 p.
2. Quin Louis D. Fundamentals of Heterocyclic Chemistry: Importance in Nature and in the Synthesis of Pharmaceuticals / Louis D. Quin, John Tyrell // Hardcover, 1st Edition. – 2010. – 327 p.
3. Zweifel George S. Modern Organic Synthesis – An Introduction / George S. Zweifel, Michael H. Nantz // Softcover, 1st Edition. – 2007. – 504 p.
4. K. C. Nicolaou. Molecules that changed the World / Nicolaou K. C., Tamsyn Montagnon // Hardcover, First Edition. – 2008. – 385 p.
5. Mundy Bradford P. Name Reactions and Reagents in Organic Synthesis / Bradford P. Mundy, Michael G. Ellerd, Frank G. Favaloro // Hardcover, 2nd Edition. – 2005. – 886 p.
6. Li Jie Jack. Name Reactions. A Collection of Detailed Reaction Mechanisms / Jie Jack Li // Hardcover, 4th Edition. – 2009. – 621 p.
7. Gallego M. Gomez. Organic Reaction Mechanisms / M. Gomez Gallego, M. A. Sierra // Hardcover, First Edition. – 2004. – 290 p.
8. Sankararaman Sethuraman. Pericyclic Reactions – A Textbook / Sethuraman Sankararaman // Softcover, First Edition. – 2005. – 418 p.
9. Tietze Lutz F. Reactions and Syntheses / Lutz F. Tietze, Theophil Eicher, Ulf Diederichsen // Paperback, First Edition. – 2007. – 598 p.
10. Olah George A. Superelectrophiles and Their Chemistry / George A. Olah, Douglas A. Klumpp // Hardcover, First Edition. – 2007. – 301 p.
11. Grossmann Robert B. The Art of Writing Reasonable Organic Reaction Mechanisms / Robert B. Grossmann // Hardcover, 2nd Edition. – 2003. – 355 p.
12. Cole Theodor C.H. Wörterbuch Labor – Laboratory Dictionary / Theodor C.H. Cole // Hardcover, 2nd Edition. – 2009. – 453 p.
The methodical instruction has been worked out by: associate prof. Dmukhulska Ye.B., assistant Medvid I.I., assistant Burmas N.I.
Methodical instruction was discussed and adopted at the Department sitting
25.06.2013. Minutes N 11
Methodical instruction was adopted and reviewed at the Department sitting
27.08.2013. Minutes N 1
