1. Chapter-1 ALCOHOLS

2. Contents IntroductionNomenclaturePreparationReactions

3. Introduction Introduction, classification, nomenclature and isomerism of alcohols : Introduction, classification, nomenclature and isomerism of alcohols : The hydroxy derivatives of aliphatic hydrocarbons (compounds having their carbon atoms in chains and not in the form of rings) are called alcohols. When one, two or more hydrogen atoms of a hydrocarbon are replaced by a corresponding number of hydroxyl groups (-OH), alcohols can be obtained. The hydroxy derivatives of aliphatic hydrocarbons (compounds having their carbon atoms in chains and not in the form of rings) are called alcohols. When one, two or more hydrogen atoms of a hydrocarbon are replaced by a corresponding number of hydroxyl groups (-OH), alcohols can be obtained.

4. Classification of Alcohols They can be classified as: They can be classified as: Alcohols with one hydroxyl group - Monohydric alcohol Alcohols with one hydroxyl group - Monohydric alcohol Alcohols with two hydroxyl groups - Dihydric alcohol Alcohols with two hydroxyl groups - Dihydric alcohol Alcohols with three hydroxyl groups - Trihydric alcohols Alcohols with three hydroxyl groups - Trihydric alcohols Alcohols with four or more hydroxyl groups - Polyhydric alcohols Alcohols with four or more hydroxyl groups - Polyhydric alcohols

5. Secondary Alcohol Secondary Alcohol Here the carbon atom bearing the hydroxyl group is attached to two other carbon atoms. Here the carbon atom bearing the hydroxyl group is attached to two other carbon atoms. Tertiary Alcohol Tertiary Alcohol Here the carbon atom bearing the hydroxyl group is attached to three other carbon atoms Here the carbon atom bearing the hydroxyl group is attached to three other carbon atoms Nomenclature of alcohols Nomenclature of alcohols In the IUPAC system, the names of saturated alcohols are derived from corresponding alkenes by replacing 'e' of alkenes by 'ol' In the IUPAC system, the names of saturated alcohols are derived from corresponding alkenes by replacing 'e' of alkenes by 'ol'

6. Some examples are shown below Some examples are shown below The numbering is done such that the carbon atom attached to the,- OH group gets the lowest number. The numbering is done such that the carbon atom attached to the,- OH group gets the lowest number.

7. For naming polyhydric alcohols, the name of the alkane is retained and the ending -e is not dropped. Thus dihydric alcohols are named as alkane diols and trihydric alcohols are named as alkene triols For naming polyhydric alcohols, the name of the alkane is retained and the ending -e is not dropped. Thus dihydric alcohols are named as alkane diols and trihydric alcohols are named as alkene triols

8. Isomerism Of Alcohols Alcohols exhibit following types of isomerism: Alcohols exhibit following types of isomerism: 1. Chain isomerism Alcohols with four or more carbon atoms exhibit this type of isomerism in which the carbon skeleton is different. Alcohols with four or more carbon atoms exhibit this type of isomerism in which the carbon skeleton is different. 2. Position isomerism Alcohols with three or more carbon atoms can exhibit position isomerism. Alcohols with three or more carbon atoms can exhibit position isomerism.

9. 3. Functional isomerism Alcohols with two or more carbon atoms can exhibit functional isomerism with ethers. Alcohols with two or more carbon atoms can exhibit functional isomerism with ethers. 4. Optical isomerism Alcohols containing chiral centrescen exhibit enantiomerismor optical isomerism. Alcohols containing chiral centrescen exhibit enantiomerismor optical isomerism.

10. Preparation A common source for producing alcohols is from carbonyl compounds. The choice of carbonyl type (ketone, aldehyde, ester, etc) and the type of reaction (Grignard addition or Reduction), will determine the product(s) you will get. T There are primarily two types of reactions used to create alcohols from carbonyls: Grignard Addition reactions and Reduction reactions.

11. Grignard Addition Reactions : Grignard Addition Reactions : Grignard reagents are created by reacting magnesium metal with an alkyl halide. The magnesium atom then gets between the alkyl group and the halogen atom with the general reaction: Grignard reagents are created by reacting magnesium metal with an alkyl halide. The magnesium atom then gets between the alkyl group and the halogen atom with the general reaction: Grignard reagents Grignard reagents R-X + Mg → R-Mg-X R-X + Mg → R-Mg-X

12.  Mechanism of Grignard reagent reacting with a carbonyl: The general mechanism of a Grignard reagent reacting with a carbonyl (except esters) involves the creation of a 6-membered ring transition state.

13. Synthesis from an Aldehyde / Ketone/Ester Synthesis from an Aldehyde / Ketone/Ester  When a formaldehyde is the target of the Grignard's attack, the result is a primary alcohol.  When an aldehyde is the target of the Grignard's attack, the result is a secondary alcohol.  When a ketone is the target of the Grignard's attack, the result is a tertiary alcohol.

15. Synthesis of alcohol from an epoxide and Grignard reagent The reaction of Grignard reagents with epoxides is regioselective. The Grignard reagent attacks at the least substituted side of the carbon-oxygen bonds, if there is one. The reaction of Grignard reagents with epoxides is regioselective. The Grignard reagent attacks at the least substituted side of the carbon-oxygen bonds, if there is one.

16. Organolithium Alternative Organolithium reagents are slightly more reactive, but produce the same general results as Grignard reagents Organolithium reagents are slightly more reactive, but produce the same general results as Grignard reagents

17. Reduction From an Aldehyde From an Aldehyde From Ketone From Ketone

18. From an Ester From an Ester From carboxylic acid From carboxylic acid

19. Acidity In an O-H bond, the O steals the H's electron due to its electronegativity, and O can carry a negative charge (R-O-). In an O-H bond, the O steals the H's electron due to its electronegativity, and O can carry a negative charge (R-O-).. This makes the -OH group (and alcohols) Bronsted acids. Alcohols are weak acids, even weaker than water.. This makes the -OH group (and alcohols) Bronsted acids. Alcohols are weak acids, even weaker than water. On the other hand, alcohols are also weakly basic, As a Bronsted base, the oxygen atom in the -OH group can accept a proton (hydrogen ion.) This results in a positively-charged species known as an oxonium ion. On the other hand, alcohols are also weakly basic, As a Bronsted base, the oxygen atom in the -OH group can accept a proton (hydrogen ion.) This results in a positively-charged species known as an oxonium ion.

20. Reactions Conversion of alcohols to haloalkanes : Conversion of alcohols to haloalkanes : This process can occur through SN2 (backside attack) or SN1 (carbocation intermediate) mechanisms. This process can occur through SN2 (backside attack) or SN1 (carbocation intermediate) mechanisms. SN2 conversion of an alcohol to a haloalkane: SN2 conversion of an alcohol to a haloalkane: R-O-H + H+ + X- → R-O+-H2 + X- → R-X + H2O R-O-H + H+ + X- → R-O+-H2 + X- → R-X + H2O SN1 conversion of an alcohol to a haloalkane: SN1 conversion of an alcohol to a haloalkane: R-O-H + H+ + X- → R-O+-H2 + X- → R+ + H2O + X- → R-X + H2O R-O-H + H+ + X- → R-O+-H2 + X- → R+ + H2O + X- → R-X + H2O

21. Oxidation With regards to alcohol, oxidizing reagents can be strong or weak. Weak reagants are able to oxidize a primary alcohol group into a aldehyde group and a secondary alcohol into a ketone With regards to alcohol, oxidizing reagents can be strong or weak. Weak reagants are able to oxidize a primary alcohol group into a aldehyde group and a secondary alcohol into a ketone Strong reagents will further oxidize the aldehyde into a carboxylic acid (COOH). Tertiary alcohols cannot be oxidized Strong reagents will further oxidize the aldehyde into a carboxylic acid (COOH). Tertiary alcohols cannot be oxidized An example of a strong oxidizing reagent is chromic acid (H2CrO4). An example of a weak oxidizing reagent is pyridinium chlorochromate (PCC) (C5H6NCrO3Cl) An example of a strong oxidizing reagent is chromic acid (H2CrO4). An example of a weak oxidizing reagent is pyridinium chlorochromate (PCC) (C5H6NCrO3Cl)

22. Glycol Ethylene glycol Ethylene glycol IUPAC name:Ethan-1,2-diol IUPAC name:Ethan-1,2-diol IUPAC name IUPAC name Other names:1,2Ethanediol Ethylene Alcohol, Other names:1,2Ethanediol Ethylene Alcohol, Hypodicarbonous acid, Hypodicarbonous acid, Monoethylene glycol Monoethylene glycol

23. Ethylene glycol (IUPAC name: ethane-1,2-diol) is an organic compound widely used as anautomotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid. Ethylene glycol is toxic, and ingestion can result in death. Ethylene glycol (IUPAC name: ethane-1,2-diol) is an organic compound widely used as anautomotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid. Ethylene glycol is toxic, and ingestion can result in death.IUPAC nameorganic compoundautomotiveantifreezeIUPAC nameorganic compoundautomotiveantifreeze Ethylene glycol was first prepared in 1859 by the French chemist Charles-Adolphe Wurtzfrom ethylene glycol diacetate via saponification with potassium hydroxide and, in 1860, from the hydration of ethylene oxide. Ethylene glycol was first prepared in 1859 by the French chemist Charles-Adolphe Wurtzfrom ethylene glycol diacetate via saponification with potassium hydroxide and, in 1860, from the hydration of ethylene oxide.FrenchCharles-Adolphe Wurtzsaponificationpotassium hydroxidehydrationethylene oxideFrenchCharles-Adolphe Wurtzsaponificationpotassium hydroxidehydrationethylene oxide

24. Current method Ethylene glycol is produced from ethylene (ethene), via the intermediate ethylene oxide. Ethylene oxide reacts with water to produce ethylene glycol according to the chemical equation- Ethylene glycol is produced from ethylene (ethene), via the intermediate ethylene oxide. Ethylene oxide reacts with water to produce ethylene glycol according to the chemical equation-ethylene oxidewaterchemical equationethylene oxidewaterchemical equation C2H4O + H2O → HOCH2CH2OH C2H4O + H2O → HOCH2CH2OH This reaction can be catalyzed by either acids or bases This reaction can be catalyzed by either acids or basesreactioncatalyzedacidsbasesreactioncatalyzedacidsbases

25. Reactions Ethylene glycol is used as a protecting group for carbonyl groups in organic synthesis. Treating a ketone or aldehyde with ethylene glycol in the presence of an acid catalyst (e.g., p- toluenesulfonic acid; BF3Et2O) gives the corresponding a 1,3-dioxolane, which is resistant to bases and other nucleophiles. The 1,3- dioxolane protecting group can thereafter be removed by further acid hydrolysis. Ethylene glycol is used as a protecting group for carbonyl groups in organic synthesis. Treating a ketone or aldehyde with ethylene glycol in the presence of an acid catalyst (e.g., p- toluenesulfonic acid; BF3Et2O) gives the corresponding a 1,3-dioxolane, which is resistant to bases and other nucleophiles. The 1,3- dioxolane protecting group can thereafter be removed by further acid hydrolysis.protecting groupcarbonyl groupsorganic synthesisp- toluenesulfonic acidBF3Et2Ohydrolysisprotecting groupcarbonyl groupsorganic synthesisp- toluenesulfonic acidBF3Et2Ohydrolysis

26. Uses: Uses: The major use of ethylene glycol is as a medium for convective heat transfer in, for example, automobiles and liquid cooled computers. Ethylene glycol is also commonly used in chilled water air conditioning systems The major use of ethylene glycol is as a medium for convective heat transfer in, for example, automobiles and liquid cooled computers. Ethylene glycol is also commonly used in chilled water air conditioning systemsconvective heat transferair conditioningconvective heat transferair conditioning In the plastics industry, ethylene glycol is important precursor to polyester fibers and resins. In the plastics industry, ethylene glycol is important precursor to polyester fibers and resins. plasticspolyesterresinsplasticspolyesterresins

27. Niche Applications Minor uses of ethylene glycol include the manufacture of capacitors, as a chemical intermediate in the manufacture of 1,4-dioxane Minor uses of ethylene glycol include the manufacture of capacitors, as a chemical intermediate in the manufacture of 1,4-dioxane1,4-dioxane. Ethylene glycol is also used in the manufacture of some vaccines.. Ethylene glycol is also used in the manufacture of some vaccines.vaccines Ethylene glycol is commonly used as apreservative for biological specimens, especially in secondary schools during dissection as a safer alternative to formaldehyde Ethylene glycol is commonly used as apreservative for biological specimens, especially in secondary schools during dissection as a safer alternative to formaldehydepreservativedissectionformaldehydepreservativedissectionformaldehyde