POSTLAB-EXPT-19-20-21-22-NOTES

Ketones

Ketones

Organic compounds characterized by the presence of the carbonyl group (-C=O) and have two other carbon groups connected to the carbonyl carbon atom.

Carbonyl group

A functional group consisting of a carbon-oxygen double bond (-C=O) found in ketones and aldehydes.

Polarity

The carbonyl group has a partially negative oxygen atom and a partially positive carbon atom, which influences the physical and chemical properties of ketones.

Solubility

Ketones with one to four carbons are soluble in water due to hydrogen bonding.

Chemical activity

Ketones are generally less chemically active than similar-sized aldehydes.

Biological significance of ketones

Ketones, such as acetone, acetoacetate, and beta-hydroxybutyrate, are important in metabolic processes, especially during fasting and starvation.

Preparations of ketones

Ketones can be prepared by oxidizing alcohols using reagents such as K2Cr2O7 and concentrated sulfuric acid.

Bradys test for aldehydes

A chemical test that detects the presence of aldehydes in a sample using 2,4-dinitrophenylhydrazine (DNPH) and concentrated sulfuric acid.

Legal's test

A chemical test used for the detection of ketones, involving the formation of a colored complex with acetone and sodium nitroprusside.

Ketals and Hemiketals

Derivatives of ketones where two ether groups are attached to a carbon atom (ketals) or intermediate products in the formation of ketals (hemiketals).

Benedict's test

A test that detects reducing sugars, resulting in the formation of a reddish-brown precipitate of copper(I) oxide.

Fehling's test

A test that identifies reducing sugars, producing a brick-red precipitate of copper(I) oxide.

Tollens test

A test that distinguishes between aldehydes and ketones, resulting in the formation of a silver mirror.

Carboxylic acids

Carbonyl compounds with a carbonyl group (-C=O) bonded to a hydroxyl group (-OH) and another group (hydrogen or aryl/alkyl).

Carboxyl group

A functional group (-COOH) consisting of a carbonyl group (-C=O) and a hydroxyl group (-OH) found in carboxylic acids.

Carboxylic Acids

Organic compounds with a carboxyl group (-COOH) that can donate a proton (H+) in aqueous solution.

IUPAC Naming

The systematic method of naming organic compounds, including carboxylic acids, by replacing the "e" of the corresponding alkane name with "oic acid" and numbering the carbon chain starting with the carboxyl carbon.

Common Names

Alternative names for carboxylic acids derived from Latin or Greek words indicating natural sources.

Properties of Carboxylic Acids

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Strong forces due to polar carbonyl and hydroxyl groups.

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High solubility in water due to polarity and hydrogen-bonding capacity.

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High boiling and melting points; many are solids at room temperature.

Applications of Carboxylic Acids

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Weak acids with a sour or tart taste.

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Produce hydronium ions, neutralize bases; react with alcohols to form esters.

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Form esters, amides, anhydrides, and acid halides; fats and oils are esters of glycerol and fatty acids.

Oxidation of Aldehydes

A method for the preparation of carboxylic acids by oxidizing aldehydes using oxidizing agents such as K2Cr2O7 and conc'd. H2SO4.

Test for Acidity of Carboxylic Acids with Different Indicators

Using litmus paper, pH paper, and methyl red to determine the acidity of carboxylic acids.

Reaction with Sodium Bicarbonate

A reaction where carboxylic acids react with sodium bicarbonate to produce carbon dioxide gas and a corresponding salt.

Tollen's Test

A test used to detect the presence of aldehydes or alpha-hydroxy ketones, which can be formed by the oxidation of carboxylic acids.

Hydrolysis of Acid Functional Derivatives

The reaction of acid functional derivatives, such as esters, amides, anhydrides, and acid halides, with water to break them down into their respective carboxylic acids.

Acidity of Carboxylic Acids

Carboxylic acids are weak acids that can donate a proton (H+ ion) in aqueous solution, resulting in the formation of carboxylate ions (RCOO-).

Formation and Characteristics of Esters

Esters are formed by the reaction of carboxylic acids with alcohols, resulting in the formation of an ester and water. They have a carboxylate group (–COOR) where the alkyl group replaces the hydrogen (H) of the carboxylic acid.

Citric Acid in the Citric Acid Cycle

Citric acid is a key intermediate in the Citric Acid Cycle (also known as the Krebs Cycle or TCA Cycle), which takes place in the mitochondria of cells and is important for cellular respiration and energy production.

Applications and Reactions of Esters

Esters are recognizable by their pleasant fruity odors and are used in perfumes, flavoring agents, and as aromas and flavors in fruits. They can be formed through esterification reactions and undergo hydrolysis. Esters also have good solvent properties and are used in paints, varnishes, and lacquers.

Hydrolysis

The most important reaction of esters, where they are split into their respective carboxylic acids and alcohols through the addition of water.

Solvent Properties

Esters are good solvents for organic substances, especially those with relatively low molar masses. Examples include ethyl acetate, butyl acetate, methyl butyrate, and isoamyl acetate.

Formation and Characteristics of Esters

Esters are formed by the reaction of carboxylic acids with alcohols, resulting in the formation of an ester and water. They have a carboxylate group (–COOR) where the alkyl group replaces the hydrogen (H) of the carboxylic acid.

Filtrate Oxidized Compound

The compound formed after heating the filtrate multiple times to oxidize it.

Observation at the Junction

The observation made at the junction of adding 0.5% Resorcinol and concentrated H2SO4 to the filtrate.

Formation of Acetyl Salicylic Acid (Aspirin)

The process of forming acetyl salicylic acid (aspirin) from salicylic acid and acetic anhydride in the presence of a catalyst.

Lactones

Cyclic esters derived from hydroxycarboxylic acids.

Examples of Lactones

Examples of lactones including γ-Butyrolactone, ε-Caprolactone, and δ-Valerolactone.

Structural Formula of Dexon

The structural formula of Dexon, which is a polyester composed of repeating units of ethylene glycol and terephthalic acid.

Use in the Medical Field

The application of Dexon in various medical applications such as surgical sutures, wound closure, and medical textiles.

Amines

Nitrogen-containing organic compounds derived from ammonia (NH3) with one or more hydrogen atoms replaced by alkyl or aromatic groups.

Amides

Derivatives of carboxylic acids with a carboxyl carbon attached to an amino group (–NH2).

Hydrogen Bonding

The ability of amines and amides to form hydrogen bonds.

Solubility and Hydrolysis

The solubility of low molecular weight amines in water due to hydrogen bonding, and the hydrolysis of amides in acidic conditions.

Applications

The various applications of amines and amides in life sciences, medicine, and the chemical industry.

Physiological Activity

The physiological activity of amines and amides, including their use in medicine as decongestants, anesthetics, sedatives, and naturally occurring alkaloids.

Biochemical Importance

The importance of amides derived from carboxylic acids in biology, particularly in proteins.

pH Test for Amines

The test to determine the pH of amines using litmus papers.

Ninhydrin Test for Amines and Amides

The test to detect amines and amides using ninhydrin reagent and observing color changes.

Biuret Test for Diamides

The test to detect diamides using urea, NaOH solution, and CuSO4 solution.

Carbylamine Reaction for Aniline

The reaction of aniline with chloroform and alcoholic KOH to produce a distinct odor.

Hinsberg Reaction

A chemical reaction that differentiates primary, secondary, and tertiary amines.

Diazotization

The formation of diazonium salts from primary aromatic amines.

Ammonolysis Reaction

The reaction of an amide with ammonia.

Biologically Important Amines

Dopamine, Serotonin, Epinephrine, and Histamine are amines with important roles in the body.