OXYGEN CONTAINING ORGANIC COMPOUNDS Electron configuration of oxygen

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OXYGEN CONTAINING ORGANIC COMPOUNDS

OXYGEN CONTAINING ORGANIC COMPOUNDS

Electron configuration of oxygen atom: 1 s 2 2 p 4 In organic molecule

Electron configuration of oxygen atom: 1 s 2 2 p 4 In organic molecule oxygen is attached covalently with two pairs of atoms O Two s bonds O One s and one p bond

q Alcohols and phenols (hydroxy derivates) – compounds with the hydroxyl (-OH) R-O-H q

q Alcohols and phenols (hydroxy derivates) – compounds with the hydroxyl (-OH) R-O-H q Ethers – compounds with alcoxyl group (-OR) R-O-R q Aldehydes and ketones – compounds with carbonyl group R C= O H q C= O - R R C=O - Carboxylic acids – compounds with carbonyl + hydroxyl group R H -O - - C = O-

Alcohols Organic analogs of water, one hydrogen carbon is replaced by an alkyl group

Alcohols Organic analogs of water, one hydrogen carbon is replaced by an alkyl group Classification In 1 o alcohol, only one carbon atom is attached to the carbon carrying the -OH group (primary carbon). q In 2 o alcohol two carbon atoms are attached to the carbon carrying the -OH group (secondary carbon). q In 3 o alcohol three other carbon atoms are attached to the carbon atom carrying the -OH group (tertiary carbon). q

Alcohols The number of hydroxyl groups, there are: Monohydroxyderivatives (monohydroxy alcohols) q Polyhydroxy acohols

Alcohols The number of hydroxyl groups, there are: Monohydroxyderivatives (monohydroxy alcohols) q Polyhydroxy acohols q Diols (dihydroxyderivatives, ) q Triols (trihydroxyderivatives) q Tetrols (tetrahydroxyderivatives) q Polyols belongs to a group of carbohydrates (sugars) q Phenols -OH attached primary to aromatic ring

Nomenclature of Alcohols The lower molecular weight alcohols have common names. Word alcohol is

Nomenclature of Alcohols The lower molecular weight alcohols have common names. Word alcohol is added after the name of the alkyl group to which the hydroxyl group is attached. methanol – methyl alcohol ethanol – ethyl alcohol 1 -propanol – propyl alcohol 2 -propanol – isopropyl alcohol 1 -butanol – n-butyl alcohol CH 3 -OH CH 3 -CH 2 -CH 2 -OH CH 3 -CH-CH 3 OH CH 3 -CH 2 -CH 2 -OH

Properties Low MW alcohols are colorless liquids of specific odour (unpleasant from C 4),

Properties Low MW alcohols are colorless liquids of specific odour (unpleasant from C 4), narcotic effect, toxic. q Polyhydroxy alcohols have sweet taste. q Higher alcohols (from C 12) are solid compounds q H-bonds → solubility in water, higher boiling points than alkanes. q

Reaction of Alcohols The –OH group generally makes the alcohol molecule polar. q The

Reaction of Alcohols The –OH group generally makes the alcohol molecule polar. q The -OH group can form hydrogen bonds to one another and to other compounds. q Alcohols, like water, act as acids or bases q http: //en. wikipedia. org/wiki/Alcohol#Physical_and_chemical_properties

Dehydratation of Alcohols n n Alcohols undergo combustion with O 2 to produce CO

Dehydratation of Alcohols n n Alcohols undergo combustion with O 2 to produce CO 2 and H 2 O. 2 CH 3 OH + 3 O 2 2 CO 2 + 4 H 2 O + Heat Dehydration removes H- and -OH from adjacent carbon atoms by heating with an acid catalyst. H OH | | H+, heat H—C—C—H H—C=C—H + H 2 O | | H H alcohol alkene

Dehydratation of Alcohols Ethers form when dehydration takes place at low temperature. q H+

Dehydratation of Alcohols Ethers form when dehydration takes place at low temperature. q H+ CH 3—OH + HO—CH 3 Two methanol CH 3—O—CH 3 + H 2 O Dimethyl ether

Oxidation of Primary Alcohols q In the oxidation [O] of a primary alcohol, one

Oxidation of Primary Alcohols q In the oxidation [O] of a primary alcohol, one H is lost from the –OH and another H from the carbon bonded to the OH. [O] Primary alcohol OH | CH 3—C—H | H Ethanol (ethyl alcohol) Aldehyde [O] O || CH 3—C—H + H 2 O Ethanal (acetaldehyde)

Oxidation of Primary Alcohols Aldehydes can easily be oxidized to produce acids q Aldehyde

Oxidation of Primary Alcohols Aldehydes can easily be oxidized to produce acids q Aldehyde [½ O 2] O || CH 3—C—H Ethanal (acetaldehyde) [½ O 2] Carboxylic acid O || CH 3—C—OH Acetic acid

Oxidation of Secondary Alcohols q The oxidation of a secondary alcohol removes one H

Oxidation of Secondary Alcohols q The oxidation of a secondary alcohol removes one H from –OH and another H from the carbon bonded to the –OH. [O] Secondary alcohol OH | CH 3—C—CH 3 | H 2 -Propanol (Isopropyl alcohol) Ketone [O] O || CH 3—C—CH 3 + H 2 O Propanone (Dimethylketone; Acetone)

Oxidation of Tertiary Alcohols q Tertiary alcohols are resistant to oxidation. [O] Tertiary alcohols

Oxidation of Tertiary Alcohols q Tertiary alcohols are resistant to oxidation. [O] Tertiary alcohols no reaction OH | [O] CH 3—C—CH 3 no product | CH 3 no H on the C-OH to oxidize 2 -Methyl-2 -propanol

Production q Methanol Obtained by heating wood to a high temperature in the absence

Production q Methanol Obtained by heating wood to a high temperature in the absence of air. q Toxic substance, temporary blindness (15 ml), permanent blindness or death (30 ml) q

Production q Ethanol (spiritus, alcohol) Obtained by fermentation from sugar juices q Fermentation from

Production q Ethanol (spiritus, alcohol) Obtained by fermentation from sugar juices q Fermentation from sugar from the hydrolysis of starch in the presence of yeast and temperature of less than 37°C q C 6 H 12 O 6 (hexose) 2 CH 3 CH 2 OH + 2 H 2 O q Acts as a depressant. q Lethal dose is 6 -8 g/kg ( 1 L of vodka)

Oxidation of Alcohol in the Body q q Enzymes in the liver oxidize ethanol

Oxidation of Alcohol in the Body q q Enzymes in the liver oxidize ethanol to acetaldehyde The aldehyde produces impaired coordination. Ethanol acetaldehyde acetic acid Oxidation of methanol in the liver produces formaldehyde CH 3 OH H 2 C=O

Ethanol – An Antidote for Methanol Poisoning Formaldehyde reacts very rapidly with proteins. q

Ethanol – An Antidote for Methanol Poisoning Formaldehyde reacts very rapidly with proteins. q Enzymes loss of the function. q Ethanol competes for the oxidative enzymes and tends to prevent the oxidation of the methanol to formaldehyde. q

Polyhydroxy Alcohols Ethylene glycol - ethane-1, 2 -diol HO–CH 2–OH q q Used as

Polyhydroxy Alcohols Ethylene glycol - ethane-1, 2 -diol HO–CH 2–OH q q Used as a radiator and automobile antifreez toxic: 50 m. L, lethal: 100 m. L Glycerol - propane-1, 2, 3 -triol (glycerin) CH 2 - OH q Present as the backbone of several important biological compounds

Phenols Class of chemical compounds consisting of a hydrohyl group (-OH) bonded directly to

Phenols Class of chemical compounds consisting of a hydrohyl group (-OH) bonded directly to an aromatic hydrocarbon group. q Phenol

Phenols with a single hydroxyl group, meaning mono hydroxyl phenols q Phenols with more

Phenols with a single hydroxyl group, meaning mono hydroxyl phenols q Phenols with more than one hydroxyl groups in the molecule, meaning poly hydroxyl phenols q Dihydroxybenzenes Components of biochemical molecules

Physical Properties of Phenols polar, can form hydrogen bond q water insoluble q stronger

Physical Properties of Phenols polar, can form hydrogen bond q water insoluble q stronger acids than water and will dissolve in 5% Na. OH q weaker acids than carbonic acid q Methyl derivatives - cresols are used to dissolve other chemicals, as disinfectants and deodorizers, and to make specific chemicals that kill insect pests.

Alcohols and phenols react with carboxylic acids, acid chlorides and acid anhydrides to form

Alcohols and phenols react with carboxylic acids, acid chlorides and acid anhydrides to form esters. q The reactions between alcohols and acids are carried out in the presence of a small amount of concentrated sulphuric acid. q H 2 SO 4 acts as a protonating agent as well as a dehydrating agent. This reaction is called esterification. q The introduction of acetyl (CH 3 CO-) group in alcohols or phenols in known as acetylation. q

Acetylation of salicylic acid produces aspirin, which possesses analgesic, anti-inflammatory and antipyretic properties.

Acetylation of salicylic acid produces aspirin, which possesses analgesic, anti-inflammatory and antipyretic properties.

Ethers Derivatives of water q An oxygen atom connected to two alkyl or aryl

Ethers Derivatives of water q An oxygen atom connected to two alkyl or aryl groups q Diethylether CH 3 -CH 2 -O-CH 2 -CH 3 Solvent and anestetic

Properties Ether molecules cannot form hydrogen bonds amongst each other, resulting in a relatively

Properties Ether molecules cannot form hydrogen bonds amongst each other, resulting in a relatively low boiling point compared to that of the analogous alcohols. q Ethers are slightly polar q

Aldehydes and Ketones Aldehydes and ketones are the oxygen analogs of alkenes q Carbonyl

Aldehydes and Ketones Aldehydes and ketones are the oxygen analogs of alkenes q Carbonyl group (C=O) is common to aldehydes and ketones q Aldehydes - the carbonyl carbon atom is bonded to at least one hydrogen atom q Ketones - the carbonyl carbon atom is bonded to two other carbons q

Nomenclature Open chain aliphatic aldehydes and ketones are derived from the names of the

Nomenclature Open chain aliphatic aldehydes and ketones are derived from the names of the corresponding alkanes by replacing the ending -e with -al and -one respectively. The common names of aldehydes are derived from the trivial names of the corresponding carboxylic acids by replacing the ending ic, for acid with aldehyde. The common names of ketones are derived by adding the names of the alkyl or aryl groups directly linked to the carbonyl group before the word ketone.

Formaldehyde Methanal Glyoxal Ethandial Acetaldehyde Ethanal Benzaldehyde Propionaldehyde Propanal Akrylaldehyde Propenal Cinnamaldehyde 3 -phenyl

Formaldehyde Methanal Glyoxal Ethandial Acetaldehyde Ethanal Benzaldehyde Propionaldehyde Propanal Akrylaldehyde Propenal Cinnamaldehyde 3 -phenyl propenal Acetone propanone Acetophenone Methylphenyl ketone Ethylmethyl ketone Butanone Cyclohexanone Benzophenone Diphenyl ketone

Formation of Hemiacetals and Acetals When an alcohol adds reversibly to an aldehyde or

Formation of Hemiacetals and Acetals When an alcohol adds reversibly to an aldehyde or ketone, the product is called a hemiacetal or hemiketal. –OH group and OR 1 group are attached to the same carbon. q Hemiacetal hydroxyl Hemiacetals are unstable. q Sugars contain both –OH and C=O groups that undergo these reactions. q

Cyclic hemiacetals containing five and six atoms in the ring can form spontaneously from

Cyclic hemiacetals containing five and six atoms in the ring can form spontaneously from hydroxyaldehydes q alcohol and carbonyl functions are contained in the same molecule

Cyclic hemiacetals are more stable than noncyclic hemiacetals. q Five and six-carbon sugars are

Cyclic hemiacetals are more stable than noncyclic hemiacetals. q Five and six-carbon sugars are important biological examples of cyclic hemiacetals. q

Reactions of Aldehydes and Ketones with Amines Aldehydes and ketones react with primary amines

Reactions of Aldehydes and Ketones with Amines Aldehydes and ketones react with primary amines to form imines, or Schiff bases (sugars with proteins, neenzymatic glycation in diabetes).

Benedict Test in Diabetes Benedict´s solution is an oxidizing agent that contains Cu 2+

Benedict Test in Diabetes Benedict´s solution is an oxidizing agent that contains Cu 2+ ion. q Aldehydes are oxidized to an acid, and Cu 2+ is reduced to Cu+, which precipitates as Cu 2 O (red precipitate). q Glucose contains an aldehyde group q

Carboxylic acids Functional group of carboxylic acids

Carboxylic acids Functional group of carboxylic acids

Carboxylic acids They are named by adding –oic acid onto the end of the

Carboxylic acids They are named by adding –oic acid onto the end of the carbon skeleton. q The –COOH group is the section responsible for the chemistry. q The substituents are named as in other aliphatic compounds q The carbon in the –COOH group is numbered carbon 1. q

Examples of carboxylic acids Formic acid Methanoic acid Stearic acid Octadecanoic acid Acetic acid

Examples of carboxylic acids Formic acid Methanoic acid Stearic acid Octadecanoic acid Acetic acid Ethanoic acid Oleic acid Cis-9 -octadecanoic acid Propionic acid Propanoic acid Butyric acid Butanoic acid Isobutyric acid Isobutanoic acid Valeric acid Pentanoic acid Palmitic acid Hexadecanoic acid Acrylic acid Propenoic acid Crotonic acid trans-2 -butenoic acid Benzencarboxylic acid b-naphtoic acid 2 -naphtalenecarboxylic acid

Properties The liquid carboxylic acids have sharp and unpleasant odors (butyric acid occurs in

Properties The liquid carboxylic acids have sharp and unpleasant odors (butyric acid occurs in rancid butter and aged cheese). q Liquid d at room temperature. q The high molecular weight acids (myristic, palmytic, stearic) are known as fatty acids. q Wax-like solids q

Two molecules of a carboxylic acid can hydrogen bond together in non-polar solvents. q

Two molecules of a carboxylic acid can hydrogen bond together in non-polar solvents. q The boiling points are high q This phenomena is due to very strong hydrogen bonding q

Acidic Properties of Carboxylic Acids It is the release of the hydrogen ion (proton)

Acidic Properties of Carboxylic Acids It is the release of the hydrogen ion (proton) to the water molecule q This forms the acid particles H+ or H 3 O+ q CH 3 COOH CH 3 CO 2 - + H+

Salts of Carboxylic acids react with bases to produce carboxylate salts. q The name

Salts of Carboxylic acids react with bases to produce carboxylate salts. q The name of salt is derived from acid name by changing –ic ending to –ate and preceding the name with the name of the methal ion (sodium acetate or sodium ethanoate). q

Esters of Carboxylic Acids Carboxylic acids can react with an alcohol to form an

Esters of Carboxylic Acids Carboxylic acids can react with an alcohol to form an esters Esters have a pleasant odor. q The aroma of many flowers, fruits, and perfumes are due to a mixture of esters. q

Esters Used as Flavoring Agents

Esters Used as Flavoring Agents