Lab Manual for Organic Pharmacy I, Study Guides, Projects, Research of Organic Chemistry

Download Lab Manual for Organic Pharmacy I and more Study Guides, Projects, Research Organic Chemistry in PDF only on Docsity! University of Asia Pacific (UAP) Department of Pharmacy Organic Pharmacy Lab Pharm 114 1* year 2"! Semester Course Instructor Taposhi Nahid Sultana Lecturer Lab Attendant Abdul Halim Mia Index Experiment No. Name ° tthe Content Experiment Laboratory etiquette; Qualitative analysis of organic samples: N/A General Introduction | Identification of functional groups; identification of drugs in dosage forms by colour change Experiment 1 Test for carboxylic Purpose, Introduction, Principle, Methodology, Observation, and group Conclusion Purpose, Introduction, Principle, Experiment 2 Test for phenolic group | Methodology, Observation, and Conclusion Purpose, Introduction, Principle, Experiment 3 Test for aldehyde and | Methodology, Observation, and ketone Conclusion Purpose, Introduction, Principle, Experiment 4 Test for aldehyde Methodology, Observation, and Conclusion Purpose, Introduction, Principle, Experiment 5 Test for ketone Methodology, Observation, and Conclusion Purpose, Introduction, Principle, Experiment 6 Test for nitro group _| Methodology, Observation, and Conclusion identieation or ove mn Purpose, Introduction, Experiment 7 a dosage Sonn Dy Corer Methodology, Observation, and change: Doxycycline capsule Conclusion 2. Sodium hydroxide Test Principle: Sodium hydroxide is a strong base that ionizes strong or weak acids. Thus, carboxylic acids are converted to salts and dissolve in aqueous solution. Non-acidic compounds will not dissolve. The reactions of carboxylic acids are shown below: oO oO dL. + NaOH@g) —»~ [ G@® + 10 R” “OH R° *o™ ONa carboxylic acid water soluble Method: Treat the sample with equal volume of dilute NaOH solution and shake well. Observation: The sample will be soluble. Inference: Carboxylic group (-COOH) is present. 3. Sodium Hydrogen Carbonate Test Carboxylic acids reacts with sodium hydrogen carbonate to produce carbon dioxide gas which can be seen in the form of a brisk effervescence. RCOOH + NaHCO, ———> RCOONa + CO, (g)+H,0 Carboxylic Brisk acid effervescence Ca(OH),(aq) + CO,(g) ~——S- CaCO(s) + H2,0() Method: Add 2-3 ml of NaHCO; solution to 0.1 -0.2 gm of sample in a test tube containing lime water [Ca(OH),] by connecting tube. Observation: Fizzing, colourless gas gives white precipitate with limewater. Inference: Carboxylic group (-COOH) is present. Experiment No. 02: Test for Phenolic groups Aim: To identify phenolic group in the provided organic compounds. Introduction: Phenols are compounds containing a hydroxyl group attached to an aromatic ring. The simplest phenol is C,H;OH that is solid in winter and liquid in summer. Phenols are generally colourless but are coloured when it comes in contact with air due to oxidation. 1. Phenol with Sodium hydroxide solution Principle: Phenol reacts with sodium hydroxide solution to give a colourless solution containing sodium phenoxide. OH O° Nat O + NaQH = ————_» O + H20 sodium phenoxide Method: Add 1-2 ml of 5% NaOH solution to 0.1-0.2 gm of the sample in the test tube and shake well. Observation: The sample is soluble in that solution. Inference: Phenolic group (Ar-OH) is present. 2. With sodium carbonate or sodium hydrogen carbonate Principle: Phenol is not acidic enough to react with either of these. Or, looked at another way, the carbonate and hydrogen carbonate ions aren't strong enough bases to take a hydrogen ion from the phenol. Unlike the majority of acids, phenol does not give carbon dioxide when you mux it with one of these. Experiment No. 03: Test for Aldehydes and Ketones Introduction: Aldehydes and Ketones are compounds containing carbonyl group. Carbonyl group consisting of a carbon atom bonded to oxygen atom by a double bond. In Aldehydes the carbonyl carbon is attached to at least one hydrogen atom and to a carbon containing group (aliphatic or aromatic radical). Formaldehyde is an exception, in which carbonyl group is attached to two hydrogen atoms. 0 oO a oO Carbonyl H H CH, 4H C,H; H group Formaldehyde Acetaldehyde Benzaldehyde But in ketones the carbonyl carbon is attached to two aliphatic or aromatic groups. O 1 O CH; CH; CsH, CH, C.H; C,H; Acetone Acetophenone Benzophenone Carbonyl] groups in aldehydes and ketones are identified by the following tests: Experiment no. 3) 2,4-dinitrophenyl hydrazine test (2,4-DNP test) Aim: To identify carbonyl group in the provided organic compounds. Principle: 2,4-dinitrophenyl hydrazine can be used to qualitatively detect the carbonyl group of an aldehyde or ketone. A positive result is indicated by the formation of an yellow or orange-red precipitate of 2,4-dinitrophenyl hydrazone. | [ CH, __-c==0 + H,N—_HN NO, ———> CH; —_c===N___. HN NO, Acetaldehyde NO, No, 2,4-Dinitrophenyl hydrazine Acetaldehyed-2,4-dinitrophenyl hydrazone CH CH; CH; —c==0 + H,N—— HN NO, ———> CH; —_c==N__ HN. NO, Acetone NO, NO, 2,4-Dinitrophenyl hydrazine Acetone-2,4-dinitrophenyl hydrazone Method: Take the 2,4-Dinitrophenylhydrazine solution (5 ml) (Brady’s reagent) in a reaction tube and add approximately 50 mg of your unknown sample. Heat the sample tube in a water bath for several minutes. Observation: A yellow-orange precipitate forms with both types of carbonyl compound. Inference: Aldehyde or ketone present. Experiment No. 04: Test for Aldehydes 1. Tollen’s Test: Aim: To identify aldehyde in the provided organic compounds. Principle: Tollen’s reagent is ammoniacal silver nitrate. Aldehydes react with Tollen’s reagent to form elemental silver, accumulated onto the inner surface of the reaction vessel, producing silver muror on the inner surface of the vessel. O oO + 2Ag(NH,),0OH ———> 2Ag(s) + + H,O +3NH, R H Tollen’s Silver = + Aldehyde Teagent es Method: Take 0.05 gm of the sample and add 2-3 drops of tollen’s reagent (ammoniacal silver nitrate solution) ina test tube. Cool the mixture in ice bath and then warm it up to 40°C ina beaker of warm water. Observation: A beautiful silver mirror on the inside of the test tube or a black precipitate of colloidal silver is observed. Inference: Aldehyde group (-CHO) is present. 2. Fehling’s Test: Aim: To identify aldehyde in the provided organic compounds. Principle: This is an important test to distinguish aldehydes from ketones. The reagents used in this test are Fehling’s solution A and Fehling’s solution B. Fehling’s solution A is an aqueous solution of copper sulphate and Fehling’s solution B is a clear solution of sodium potassium tartrate (Rochelle salt) and strong alkali (usually NaOH). The final Fehling’s solution is obtained by mixing equal volumes of both Fehling’s solution A and Fehling’s solution B that has a deep blue colour. In Fehling’s solution, copper (II) ions form a complex with tartrate ions in alkali. Aldehydes reduces the Cu(II) ions in the fehling’s solution to red precipitate of cuprous oxide(copper (I) oxide). RCHO + 2Cu2* + 50H ——— > Cu,0 (s) + RCOO (s) + 3H,0 Aldehyde Cuprous oxide Fehling’s solution (Red) Note: Benzaldehyde may or may not give this test as the reaction is very slow. Method: Take 0.05 gm of the sample and add 2-3 ml of the Fehling’s reagent (equal amount of Fehling’s solution A and B). Shake the test tube well and heat it on a boiling water bath for 10-15 minutes. Observation: A brown or brick red ppt. is observed. Experiment No. 06: Test for Nitro Groups (-NO,) Introduction: Nitro compounds are those in which the “NO,” is attached to an alkyl or aryl group. These compounds are characterised by their odour and colour. Most of them are generally yellow in colour while the intensity of colour increases with the increase in the number of nitro groups. Aim: To identify nitro groups in the provided organic compounds. 1) Reaction with zi 1 ium chloride: Principle: In this test nitro group on treatment with ammonium chloride and zinc is partially reduced to hydroxyl amine which then acts as a reducing agent to give a positive Tollen’s test. These hydroxylamines on warming with ammoniacal silver nitrate solution (Tollen's reagent) get oxidised to nitroso compounds and reduce Tollen's reagent to metallic silver (which deposits as a silver mirror). This reaction is used to test nitro compounds and is known as the Baker-Mullikens test. iken’s Test It isa test for a nitro group. In this test, nitro compounds om reduction with zine dust and ammonium chloride yield M-arylhydroxylamines. Since aryihydroxylamines are reducing agents, they give silver mirror when treated with Tollen's reagent. This forms the basis of Mulliken's test for a nitro group. C.HNO, + 220 + 4NHACI > C,H, NHOH + 2ZaCl, + HG + 4NH, NePhenylbydiroxylami: cumemon + ago 2. 2ag + con No (iteducing sment) ‘Sitver mabrroe Method: Boil a small amount of the supplied sample with 5 ml of 5% alcohol, 0.2 gm each of NH,Cl and zinc dust. Cool, filter and add 2 ml of Tollen’s reagent to the filtrate. Moderately heat the sample ia water bath. Observation: Black grey ppt.is formed. Inference: Nitro group is present. 2) Azo- dye formation Principle: Aromatic nitro compounds may be reduced to amino compounds with tin and HCl. Azo dye test can then be performed on the reduced product. The test is applicable only if the original compound does not undergo the azo dye test. NaNOs ppt R NH o eaHci \ \ \ cl OH cI oe 4 oN ~ 2-naphthol OH con ne Orange ppt. Method: Heat 0.1 gm of the sample with 0.5 ml of conc. HCl and 2-3 small piece of metallic tin for 3-4 minutes. Filter, cool and add 3 ml aqueous solution of NaNO). Pour this content into a beaker containing alkaline beta napthol. Observation: Orange-red dye is formed. Inference: Nitro group is present. Experiment Name: Identification of drugs in dosage form by colour change Aim: To identify drugs in different dosage forms by colour change Exp Dosage Form | Method Observation No. 7 Doxycycline | To 0.5 mg of the contents of the capsules add] A yellow color is capsule 2ml of sulphuric acid. produced.