Organic Preparations.

Slides:



Advertisements
Similar presentations
Preparation of Salts By SK Chan. Preparing sodium chloride Add NaOH to HCl slowly to get a neutral solution. (How?) Concentrate the solution by evaporation.
Advertisements

Skema sbp paper 2 essay part c no. 9, 10
Preparation of a haloalkane. Haloalkanes can be made by a substitution reaction with an alcohol. Tertiary alcohols are the most reactive, and therefore.
Evaluation preparation
 Red Ink --> Answers  Blue Ink --> Teacher’s Explanation.
Chapter 4 Oceans Chapter 4 Oceans 4.1 Introducing oceans and seas
Bromobutane. Halogenoalkanes Halogenoalkanes are hydrocarbon chains that have one or more hydrogen atom(s) exchanged for halogen atom(s).
1 Chapter 3 Oceans 3.1 Introducing oceans and seas 3.2 Composition of sea water 3.3 Extraction of common salt from sea water 3.4 Tests for sodium and.
Solution of different salts
Methods of Purification
Chapter 3: Separation Techniques
Preparation and identification of an aldehyde. Primary alcohols are oxidised to form aldehydes and then carboxylic acids. Propan-1-olPropanal Propanoic.
Extractions Mixture of benzoic acid, anthracene, and p-nitroaniline.
Recrystallization Impure benzoic acid
AL CHEM REVIEW ORGANIC CHEMISTRY. AL CHEM Written Practical [Organic Chemistry] p.1 ~ Organic Synthesis ~ Organic Acid separate How to separate the product.
Experimental Reports Next week is the final week of practicals Make sure you are up to date with your reports by next week – all reports no later than.
 All salts are ionic compounds.  A salt is formed when a metallic ion or an ammonium ion (NH 4 + ) replaces one or more hydrogen ions of an acid. HClNaCl.
Lipids.
Qualitative organic analysis
Making Salts Soluble salt Insoluble salt Acid + excess insoluble solid
Salt soluble? yes, then choose an acid and a base base soluble? yestitrationno excess base no precipitation choose two soluble salts.
Alcohols IB Chemistry Topic Alcohols Asmt. Stmts Describe, using equations, the complete combustion of alcohols Describe, using.
Chapter 3: Separation Techniques
Copper sulfate solution and potassium iodide solution
Solubility Noadswood Science, 2012.
PURIFCATION OF ORGANIC COMPOUNDS
iGCSE chemistry Section 4 lesson 1
AS Revision Lessons Identification tests.
Complete the table NameFormulaStructure+ O 2 Miscibility in water methaneCH 4 CO 2 + H 2 OImmiscible ethaneC2H6C2H6 CO 2 + H 2 OImmiscible propaneC3H8C3H8.
Lab Activity 5 Lipids IUG, 2016 Dr. Tarek Zaida IUG, 2016 Dr. Tarek Zaida 1.
Separation Techniques
Chemical Changes and Structure
Acids and Alkalis.
Calculations Formula mass MgO C3H7OH Ca(OH)2 CH3COOC4H =40
Separating a Soluble and Insoluble Substance
Sulphur.
Acids and Alkalis Grade 10.
Leaving Certificate Chemistry
26 Cannizzaro Reaction The disproportionation reaction of aldehydes without α-hydrogens in presence of a strong base to produce an alcohol and a carboxylic.
Biochemistry lab 4 (Proteins)
Bottle containing ammonium nitrate
Purification and Separation Techniques
What type of reaction is this?
Leaving Certificate Chemistry
What type of reaction is this?
Purity, formulations and chromatography
Standard pattern in writing experimental procedures
Separation of mixtures
SEPARATION TECHNIQUES
Testing for carbonyl compounds
AQA GCSE Chemistry Required Practicals – Integrated Instructions – v0
Extractions Mixture of benzoic acid, anthracene, and p-nitroaniline.
Leaving Certificate Chemistry
Separating mixtures MARTIN 2011.
Chemistry.
Year 7 multiple-choice main test: answers 7H Solutions
Lipids-I.
Recrystallization Impure benzoic acid
TESTING FOR CATIONS QUALITATIVE ANALYSIS.
SOLUTION AND FILTRATION
Mixture Separation Techniques
Synthesis of Benzoyl Glycine
Dissolving and separating solutions
Test on Carboxylic Acids
Organic Preparations Question 2
Title: Acids and bases Complete the activities listed below
Recrystallization Impure benzoic acid
Organic chemistry Question Section A.
15/09/ /09/2019 Chemical Analysis AQA 2016 Chemistry topic 8.
Test on Ethyne.
Presentation transcript:

Organic Preparations

Preparation of Ethene

Unsaturated: Decolourises Bromine water ⇒product 1,2 dibromoethane Aluminium Oxide White powder. Dehydrating Agent. Glass Wool holds Ethanol. Safety: Remove delivery tube when heating stopped to prevent suck-back. Burns with a luminous flame. Unsaturated: Decolourises Bromine water ⇒product 1,2 dibromoethane www.pdst.ie Ripening Fruit, Manufacture of Polymers

Ethene C2H4 Carbon atoms are planar

Preparation of Ethyne CaC2 + 2H2O → Ca(OH)2 + C2H2 Calcium Dicarbide: Grey lumpy solid Ca(OH)2 is a white solid. Acidified Copper Sulfate (CuSO4): removes phosphine and hydrogen sulphide. Burns with a Yellow Smokey Flame C2H2 + 2½ O2 → 2CO2 + H2O Unsaturation: Decolourises Bromine Water C2H2 + 2Br2 C2H2Br4 Oxyacetylene torch, cutting and welding Safety: gas flammable/no naked flame.

Preparation of Ethyne

Ethyne C2H2

Preparation of Benzoic Acid 3C6H5CH2OH + 4KMnO4 → 3C6H5COOH + 4MnO2 + H2O + 4KOH Flask: KMnO4 + Phenylmethanol(colourless liq.) + Na2CO3 The KMnO4 is saturated to ensure complete oxidation. The sodium carbonate ensures the solution is alkaline; Mn+7 (purple) → Mn+4 (brown) → Mn +2 (colourless) Benzaldehyde forms first then sodium benzoate. Conc. HCl is added in fume hood: convert sodium benzoate to benzoic acid to neutralise the excess sodium carbonate added and potassium hydroxide produced to provide an acidic medium to enable sodium sulphite to reduce Mn4+ to Mn2+.

C6H5COOH

3C6H5CH2OH + 4KMnO4 → 3C6H5COOH + 4MnO2 + H2O + 4KOH Sodium sulphite is a reducing agent and reduces Mn4+ to Mn2+ in acid conditions The brown MnO2 would contaminate the benzoic acid Flask placed in ice to accelerate crystallisation of acid. Benzoic acid is isolated by vacuum filtration. Crystals washed with ice water. Damp crystals placed in desiccator to dry. Phenylmethanol Mr=108 Benzoic acid Mr=122 Food Preservative/Antiseptic.

Sample: Benzoic acid + NaCl (Soluble) + charcoal (Insoluble) Dissolve in a Min. of hot water (ensures a better yield) Hot filter removes Charcoal on filter paper. Benzoic acid and sodium chloride in filtrate. Evaporate until crystals begin to form. Cool in ice: NaCl soluble in cold water. Benzoic acid crystals form in cold water. Vacuum filtration collects benzoic acid Wash with ice water NaCl in filtrate. Damp crystals placed in desiccator to dry.

Melting Point Determination of Benzoic acid

Melting Point Determination of Benzoic acid Observe the melting point range of the crystals. i.e the temperature at which liquid first appears and the temperature at which no solid remains. Melting point range of an impure substance is lower and broader than that recorded for a pure sample of the same substance. Impure sample melting points 115 –118 0C (bigger range less sharp) Pure sample 120 – 121 0C (smaller range, sharp)

Preparation of Soap (I)

Preparation of Soap (I) Flask contents: Oil (lard) + Ethanol + NaOH + antibumping granules. Ethanol is solvent for oil and sodium hydroxide Granules for smooth boiling. Reaction: Substitution. Base hydrolysis of ester (animal fat (lard) or vegetable oil) Reflux: evaporation followed by condensation. Ensures complete reaction between oil and sodium hydroxide and prevents any loss of reactants or products. KOH more soluble in ethanol than NaOH (need some water)

Preparation of Soap (II)

Preparation of Soap (II) Ethanol removed by distillation as it keeps soap in solution. Dissolve residue in flask with some hot water. Brine (NaCl) used to precipitate soap. Brine will contain ethanol, glycerol, sodium hydroxide and water at the end. Collect soap by vacuum filtration and wash with a little cold water or brine to remove NaOH. Dry in desiccator

Extraction of Clove oil (I) Eugenol

Extraction of Clove oil (I) The bottom of the safety tube should be well below the water surface in the steam generator, but not touching the bottom of the flask. Disconnect steam generator when heating stopped to prevent suckback. This method allows extraction of oil at a lower temperature than heating directly. Heating directly can cause decomposition or charring. Whole cloves have more oil than ground cloves. Cloudy milky emulsion (water + Eugenol)

Solvent Extraction of Clove oil

Solvent Extraction of Clove oil Solvent used is Cyclohexane Shake mixture and open tap to release any pressure built up. Open tap and collect aqueous layer Pour organic layer out through top of funnel. Add more cyclohexane to water layer and repeat procedure. Place all organic liquid in a flask and add a dehydrating agent. Anhydrous Magnesium Sulfate is drying agent. Forms clumps, Filter to remove salt and wash with a little cyclohexane Leave mixture in fume hood overnight to evaporate cyclohexane.

Paper Chromatography.

Paper Chromatography. Apply mixture using dropper (capillary tube) or spot on paper slightly above solvent Solvent moves up separating components. Different components of a mixture have different interactions with the stationary and mobile phases.

ORGANIC PREPARATIONS Preparation of Ethyne Extraction of Clove Oil Recrystallisation and Melting Point of Benzoic acid Preparation of Ethene Preparation of Soap Preparation of Benzoic Acid Paper Chromatography

Aldehydes v Ketones Test Aldehyde Ketone Mix Fehlings 1 and 2 Add aldehyde/ketone Heat gently. Blue to red precipitate of copper (I) oxide No reaction Add aldehyde/ketone to Tollens reagent in clean test tube Heat gently Silver mirror forms Add aldehyde/ketone to acidified potassium dichromate Orange solution turns green

Alcohol to Aldehyde to Acid Colour Change Cr2O72 – Cr3+ Orange Green

Reactions of Acids Reactions of Carboxylic Acids CH3COOH + Na2CO3 ➞ 2CH3COONa + CO2 + H2O CH3COOH + NaOH → CH3COONa + H2O 2CH3COOH + Mg ➞ (CH3COO)2Mg + H2 CH3COOH + CH3OH ➞ CH3COOC2H5 + H2O Turns universal indicator red

The End