LECTURE 2 THEME: Structure and chemical properties of carboxylic acids. Heterofunctional compounds. Lecturer: Yevheniya. B. Dmukhalska

Plan Nomenclature of carboxylic acids Physical properties of carboxylic acids. Classification of carboxylic acids Methods of preparation of carboxylic acids Chemical properties of carboxylic acids. Heterofunctional compounds. Hydroxy-acids, nomenclature, isomerism, chemical properties and specific reactions for hydroxy-acids. Introduction of optical isomerous. Mirror (optical) isomerism. Asymmetric carbon atom. Properties of enantiomers.

Carboxylic acids Carboxylic acids are compounds whose characteristic functional group is the carboxyl group - COOH , example: Common formula of carboxylic acid:

Nomenclature of carboxylic acids Formula Common Name IUPAC Name HCO2H formic acid methanoic acid CH3CO2H acetic acid ethanoic acid CH3CH2CO2H propionic acid propanoic acid CH3(CH2)2CO2H butyric acid butanoic acid CH3(CH2)3CO2H valeric acid pentanoic acid CH3(CH2)4CO2H caproic acid hexanoic acid CH3(CH2)5CO2H enanthic acid heptanoic acid CH3(CH2)6CO2H caprylic acid octanoic acid CH3(CH2)7CO2H pelargonic acid nonanoic acid CH3(CH2)8CO2H capric acid decanoic acid

Classification of carboxylic acids : 1. By the nature of hydrocarbon radical a) saturated acids; b) unsaturated acids c) aromatic acid 2. By the number of carboxyl groups a) monocarboxylic acids; b) dicarboxylic acids.

Saturated acids are acids, which have only simple bonds in molecule. Example: methanoic (formic) acid ethanoic (acetic) acid propanoic (propionic acid) acid stearic acid (octadecanoic acid) CH3-(CH2)16-COOH

Unsaturated acid is an acid, which has both as simple bonds and duble bonds in molecule. Example: CH2=CH-COOH

Aromatic acid is acid, which contain aromatic ring. Example: benzoic acid.

Monocarboxylic acid is acid, which has one carboxylic group in molecule. Example: acetic acid, formic acid, buthanic acid.

Dicarboxylic acid is acid, which has two carboxylic group in molecule. Example: oxalic acid, malonic acid.

The names of some saturated monocarboxylic acids Structural formula Name of nomenclature trivial substitute rational formic acid methanoic acid - acetic acid etanoic acid propionic acid propanoic acid methylacetic acid oil acid butanoic acid ethylacetic acid iso oil acid 2-methylpropanoic acid dimethylacetic acid valeric acid pentanoic acid propylacetic acid iso valeric acid 3-methylbutanoic acid methylethylacetic acid CH3-(CH2)4-COOH capronic acid hexanoic acid n-butylacetic acid CH3-(CH2)10-COOH lauric acid dodecanoic acid CH3-(CH2)12-COOH myristic acid tetradecanoic acid CH3-(CH2)14-COOH palmitic acid hexadecanoic acid CH3-(CH2)16-COOH stearic acid octadecanoic acid

The names of some unsaturated monocarboxylic acids Structural formula Name of nomenclature trivial substitute CH2=CH-COOH acrylic acid propenoic acid methacrylic acid 2-methylpropenoic acid CH2=CH-CH2-COOH vinyl acetic acid 3-butenoic acid crotonic acid trans-2-butenoic acid iso crotonic acid cus-2-butenoic acid propiolic acid propionoic acid tetrolic acid 2-butynoic acid oleic acid cus-9-octadecenoic acid Linoleic acid cus-9-cus-12-octadecadienoic acid linolenic acid cus-9-cus-15-octadecatrienoic acid

Structural formula Name of nomenclature trivial substitute The names of some dicarboxylic acids Structural formula Name of nomenclature trivial substitute HOOC-COOH oxalic acid ethandioic acid HOOC-CH2-COOH malonic acid propandioic acid HOOC-CH2-CH2-COOH succinic acid butandioic acid HOOC-CH2-CH2-CH2-COOH glutaric acid pentandioic acid HOOC-CH2-CH2-CH2-CH2-COOH adypinic acid hexandioic acid HOOC-(CH2)5-COOH pimelic acid heptadioic acid HOOC-(CH2)6-COOH cork acid octandioic acid maleic acid cus-butendioic acid fumaric acid trans-butendioic acid phthalic acid 1,2-benzoldicarbonic acid iso phthalic acid 1,3-benzoldicarbonic acid

Methods of preparation of carboxylic acids. Oxidation of alkylbenzenes. Oxidation of primary alcohols. Oxidation of aldehydes.

4. Synthesis of carboxylic acids by the hydrolysis of nitriles.

Properties of Carboxylic Acids Physical Properties of Carboxylic Acids Formula IUPAC Name Melting Point Boiling Point HCO2H methanoic acid 8.4 ºC 101 ºC CH3CO2H ethanoic acid 16.6 ºC 118 ºC CH3CH2CO2H propanoic acid -20.8 ºC 141 ºC CH3(CH2)2CO2H butanoic acid -5.5 ºC 164 ºC CH3(CH2)3CO2H pentanoic acid -34.5 ºC 186 ºC CH3(CH2)4CO2H hexanoic acid -4.0 ºC 205 ºC CH3(CH2)5CO2H heptanoic acid -7.5 ºC 223 ºC CH3(CH2)6CO2H octanoic acid 16.3 ºC 239 ºC CH3(CH2)7CO2H nonanoic acid 12.0 ºC 253 ºC CH3(CH2)8CO2H decanoic acid 31.0 ºC 219 ºC

Solubility of carboxylic acids

Chemical properties of carboxylic acids.

Reduction reaction. Carboxylic acids are reduced to primary alcohols by the powerful reducing agent lithium aluminum hydride.

Salt formation Sodium butanoate Magnesium acetate Calcium acetate

α-halogenation of carboxylic acids This method of α bromination of carboxylic acids is called the Hell–Volhard– Zelinsky reaction.

Substitution of the Hydroxyl Group Except reaction 3

1. ESTERIFICATION This page looks at esterification - mainly the reaction between alcohols and carboxylic acids to make esters.

Reaction with halo-compounds: 2. Formation of acyl chlorides. Formation of acyl chlorides. Thionyl chloride reacts with carboxylic acids to yield acyl chlorides. Reaction with halo-compounds:  

3. Preparation of Acid Anhydrides

4. The formation amides.

Formation of the biuret and a biuret reaction urea

Decarboxylation of carboxylic acids. The loss of a molecule of carbon dioxide from a carboxylic acid is known as decarboxylation.

8. Carboxylic acid derivatives. These classes of compounds are classified as carboxylic acid derivatives. All may be converted to carboxylic acids by hydrolysis.

Sphingosine Monofunctional group – contains only 1 functional group. Functional groups are groups of atoms found within molecules that are involved in the chemical reactions characteristic of those molecules. There are mono-, poly- and heterofunctional group in the structure of organic compounds: Monofunctional group – contains only 1 functional group. C2H5—OH Polyfunctional group – contains several similar functional group. Heterofunctional group – contains several different functional group. Sphingosine

Biological role: Heterofunctional compounds are widespread in the nature. They are in fruits and vegetable leafs. Also they are formed in body. So, the lactic acid is product of transformation glucose (glycolysis) in human body. A malic and citric acid formed in a cycle of tricarboxylic acids, which is also known as citric acid cycle or Krebs' cycle. Hydroxo acids such as: pyruvic acid, acetoacetic acid, oxaloacetic acid, -ketoglutaric acid are important in metabolism of carbohydrates.

Hydroxyacids Hydroxyacids are the derivatives of carboxyl acids that contain –OH group (1 or more). β α 2-hydroxypropanoic acid α-hydroxypropanoic acid

α,α’-dihydroxysuccinic acid, 2,3-dihydroxybutandioic acid, glycolic acid, hydroxyacetic acid, hydroxyethanoic acid tartaric acid α,α’-dihydroxysuccinic acid, 2,3-dihydroxybutandioic acid, lactic acid, α- hydroxypropanoic acid, 2- hydroxypropanoic acid malic acid, hydroxysuccinic acid hydroxybutanedioic acid citric acid, 2-hydroxy-1,2,3-propantricarboxylic acid

Methods of preparation of hydroxyacids: Hydrolysis of α-halogenoacids Oxidations of diols and hydroxyaldehydes Hydration of α,β-unsaturated carboxylic acids Hydrolysis of hydroxynitriles (cyanohydrins) lactic acid β-hydroxypropanoic acid

Physical and chemical properties of hydroxycarboxylic acid For physical properties of hydroxycarboxylic acids are colorless liquids or crystalline substance, soluble in water. Chemical properties: Carboxyl group can react forming: a) salts: sodium β-hydroxypropanoic acid

Ester formation: Methyl-β-hydroxypropanoate Methyl-β-methoxylpropanoat β-ethanoatepropanoic acid

a) hydrohalogens (HCl, HBr, HI, HF) c) Amides formation: II. –OH group reaction: a) hydrohalogens (HCl, HBr, HI, HF) b) can oxidize amide of β-hydroxypropanoic acid β-oxopropanoic acid

Related to heat of: lactic acid 1. α-hydroxyacids lactide

Decomposition α-hydroxyacids Ethanal formic acid

3,4,5-trihydroxybenzoic acid, Phenolacids. Phenolacids are the derivatives of aromatic carboxyl acids that contain –OH group (1 or more). salicylic acid, 2-hydroxybenzoic acid o-hydroxycinnamic acid 4-hydroxybenzoic acid 3,4,5-trihydroxybenzoic acid, gallic acid

Phenolacids are the derivatives of aromatic carboxyl acids that contain –OH group (1 or more). Decarboxylation

Representatives of hydroxyacids: Lactic acid is a trivial name because at first it was extracted from milk. It is present in yogurt, sour milk and other milk products. It can form in muscles during hard and prolonged work. Salts of milk acid are used in medicine. Malic acid. It is present in green apples and some berries. It takes part in biological processes in human organisms and organisms of other alive creatures. It is used in medicine for synthesis of some medical preparations. Tartaric acid . It is present in grape. It is used in medicine for synthesis of some medical preparations.

Citric acid. It is present in. orange, lemon and other. citric fruits Citric acid . It is present in orange, lemon and other citric fruits. It takes part in biological processes in human organism.

Oxoacids To oxoacids include aldehydo- and ketonoacids. These compounds include in the structure of the carboxyl group, aldehyde functional group or ketone functional group. acetoacetic acid, 3-oxobutanoic acid, β-ketobutyric acid glyoxylic acid, oxoethanoic acid Pyroracemic (pyruvic) acid, 2-oxopropanoic acid oxalacetic acid, oxobutanedioic acid, ketosuccinic acid γ-ketovaleric acid, 4-oxopentanoic acid, levulinic acid ketoglutaric acid

Chemical properties of oxoacids Decarboxylation of α-oxoacids Decarboxylation of β-oxoacids

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