Unsaturated carboxylic acids

Chemical properties.
The chemical properties of unsaturated carboxylic acids are due to both the properties of the carboxyl group and the properties of the double bond. Acids with a double bond located close to the carboxyl group – alpha, beta-unsaturated acids – have specific properties. For these acids, the addition of hydrogen halides and hydration go against Markovnikov’s rule:

CH 2 u003d CH-COOH + HBr -> CH 2 Br-CH 2 -COOH

With careful oxidation, dihydroxy acids are formed:

CH 2 u003d CH-COOH + [O] + H 2 0 -> HO-CH 2 -CH (OH) -COOH

In vigorous oxidation, the double bond is broken and a mixture of different products is formed, from which the position of the double bond can be determined. Oleic acid C 17 H 33 COOH is one of the most important higher unsaturated acids. It is a colorless liquid that hardens in the cold. Its structural formula is: CH 3 -(CH 2 ) 7 -CH=CH-(CH 2 ) 7 -COOH.

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Derivatives of carboxylic acids

Derivatives of carboxylic acids are compounds in which the hydroxyl group of the carboxylic acid is replaced by another functional group.

Ethers are organic compounds having the formula RO-R’, where R and R’ are hydrocarbon radicals. However, it should be taken into account that such a group may be part of other functional groups of compounds that are not ethers.

Esters (or esters ) are derivatives of oxo acids (both carboxylic and inorganic) with the general formula R k E (= O) l (OH) m , where l ≠ 0, formally being the products of substitution of hydrogen atoms of hydroxyls —OH of the acid function by hydrocarbon residue (aliphatic, alkenyl, aromatic or heteroaromatic); are also considered as acyl derivatives of alcohols. In the IUPAC nomenclature, esters also include acyl derivatives of chalcogenide analogs of alcohols (thiols, selenols, and tellurols) [1] .

They differ from ethers (ethers), in which two hydrocarbon radicals are connected by an oxygen atom (R 1 —O—R 2 )

Amides are derivatives of oxo acids (both carboxylic and mineral) R k E (= O) l (OH) m , (l ≠ 0), which are formally products of substitution of hydroxyl groups -OH of the acid function with an amino group (unsubstituted and substituted); are also considered as acyl derivatives of amines. Compounds with one, two or three acyl substituents at the nitrogen atom are called primary, secondary and tertiary amides, secondary amides are also called imides.

Amides of carboxylic acids – carboxamides RCO-NR 1 R 2 (where R 1 and R 2 are hydrogen, acyl or an alkyl, aryl or other hydrocarbon radical) are usually referred to as amides, in the case of other acids in accordance with the IUPAC recommendations when naming an amide as a prefix the name of the acid residue is indicated, for example, amides of sulfonic acids RS (= O 2 NH 2 are called sulfamides.

Carboxylic acid chloride (acyl chloride) is a derivative of a carboxylic acid in which the hydroxyl group -OH in the carboxyl group -COOH is replaced by a chlorine atom. The general formula is R-COCl. The first representative with R=H (formyl chloride) does not exist, although the mixture of CO and HCl in the Gattermann-Koch reaction behaves like formic acid chloride.

Receipt

R-COOH + SOCl 2 → R-COCl + SO 2 ↑ + HCl ↑

Nitriles are organic compounds of the general formula R—C≡N, which are formally C-substituted hydrocyanic acid derivatives HC≡N

Kapron (poly-ε-caproamide, nylon-6, polyamide 6) is a synthetic polyamide fiber derived from petroleum, a product of caprolactam polycondensation

[—HN(CH 2 ) 5 CO—] n

In industry, it is obtained by polymerization of a derivative

Nylon (eng. nylon ) is a family of synthetic polyamides used primarily in the production of fibers.

Two types of nylon are most common: polyhexamethylene adipamide ( anide (USSR/Russia), nylon 66 (USA)), often called nylon itself, and poly-ε-caproamide ( kapron (USSR/Russia), nylon 6 (USA)). Other species are also known, for example, poly-ω-enanthoamide ( enanth (USSR/Russia), nylon 7 (USA)) and poly-ω-undecanamide ( undecane (USSR/Russia), nylon 11 (USA), rilsan (France, Italy)

Anide fiber formula: [—HN(CH 2 ) 6 NHOC(CH 2 ) 4 CO—] n [1] . Anide is synthesized by polycondensation of adipic acid and hexamethylenediamine. To ensure the 1:1 stoichiometric ratio of reagents necessary to obtain a polymer with a maximum molecular weight, a salt of adipic acid and hexamethylenediamine ( AH-salt ) is used:

R = (CH 2 ) 4 , R’ = (CH 2 ) 6

The formula of fiber from kapron (nylon-6): [—HN(CH 2 ) 5 CO—] n [1] . The synthesis of capron from caprolactam is carried out by hydrolytic polymerization of caprolactam according to the “ring-opening-addition” mechanism:

Plastic products can be made from rigid nylon – ecolon, by injecting liquid nylon into the mold under high pressure, which achieves a greater density of the material.

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Classification

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KETO ACIDS are organic substances whose molecules include carboxyl (COOH—) and carbonyl (—CO—) groups; serve as precursors for many compounds that perform important biological functions in the body. Significant metabolic disorders that occur in a number of pathological conditions are accompanied by an increase in the concentration of certain keto acids in the human body.

keto enol tautomerism

Methods for obtaining Alpha and Beta keto acids

α-Keto acids are obtained by oxidation of α-hydroxy acids.

β-Ketoacids, due to their instability, are obtained from esters by Claisen condensation.

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In organic chemistry, the term “oxidation reaction” implies that it is the organic compound that is oxidized, while the oxidizing agent in most cases is an inorganic reagent.

Alkenes

KMnO 4 and H 2 O (neutral medium)

3CH2 u003d CH2 + 2KMnO 4 + 4H 2 O u003d 3C 2 H 4 (OH) 2 + 2MnO 2 + 2KOH – complete equation

KMnO4 and H +

(acid environment)

double bond is broken:

R-CH 2 u003d CH 2 -R + [O] → 2R-COOH – schematic equation

Alkylarenes

Eitlbenzene-alkylarene

Ketones

Ketones are very resistant to the action of oxidizing agents and are oxidized only by strong oxidizing agents when heated. During the oxidation process, the CC bonds on both sides of the carbonyl group are broken and in the general case a mixture of four carboxylic acids is obtained:

The oxidation of a ketone is preceded by its enolization, which can take place both in an alkaline and in an acidic environment:

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Tartaric acid (dioxisuccinic acid, tartaric acid, 2,3-dihydroxybutanedioic acid) HOOC-CH(OH)-CH(OH)-COOH is a dibasic hydroxy acid. Salts and anions of tartaric acid are called tartrates.

Three stereoisomeric forms of tartaric acid are known: D-(-)-enantiomer (top left), L-(+)-enantiomer (top right) and meso -form (mesotartaric acid):

Diastereomers are stereoisomers that are not mirror images of each other [1] . Diastereomerism occurs when a compound has multiple stereocenters. If two stereoisomers have opposite configurations of all their respective stereocenters, then they are enantiomers.

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