CARBOXYLIC ACID DERIVATIVE

CARBOXYLIC ACID DERIVATIVE

 

Carboxylic acid derivative is a derivative of a carboxylic acid, where the terms of the structure of compounds obtained from the turn of the-OH group in the structure of the formula RCOOH by the-NH2,-OR, or-OOCR. The carboxylic acid derivatives are more specifically discuss acid halide, acid anhydride, ester, amide, and nitrile. All carboxylic acid derivatives having acyl functional group (RCO-) or aroil (ARCO-) and when hydrolyzed produce carboxylic acids. Therefore, the force causes the carbonic carboxylic acid derivatives are polar, and this polarity effect on the properties that exist in carboxylic acid derivatives.

A. Carboxylic Acid Derivatives reactivity

Carboxylic acid derivative is a compound that produces carboxylic acids when hydrolyzed. Unlike aldehydes and ketones, carboxylic acid-containing derivatives of group living, electronegative groups that can be lost as an anion (X-or RCO2-) or as an anion protonated (ROH or R2NH).

And please note that all derivatives containing acyl group, RCO-, except for the nitrile.

In group-containing carboxylic acid derivatives are bound to go on the acyl carbon, while the aldehydes and ketones are not. Usually mengadisi reagents on the carbonyl group of ketones or aldehydes, but substitute the left is the acid derivatives.

B. Spectral properties of Carboxylic Acid Derivatives

Spectra of a number of carboxylic acid derivatives to give a little information about the functionality than the infrared spectra provide more information about the types of functional groups.

1. Hydrochloric acid

Infrared carbonyl absorption of acid chloride is found at a frequency slightly higher than the catchment for other acid derivatives.

2. Anhydride

In general, the carbonyl anhydride showed double peak in the infrared spectrum.

3. Ester

Infrared absorption of the aliphatic ester carbonyl of about 1740 cm-1 (5.75 mm), but the conjugated ester absorbs at a slightly lower frequency.

4. Amide

The position of an amide carbonyl group absorption varied and depend on the extent of hydrogen bonding between molecules. Infrared spectrum of a pure liquid amides showed a band called amide peak I. The amide is distinguished by the primary amide, secondary amide, and tertiary amides.

5. Nitrile

Absorption found in the C º N triple bond region of the infrared spectrum and the intensity of medium to weak.

C. Carboxylic acid derivatives of

A. Acid halides

a) Nomenclature Acid Chloride

Hydrochloric acid was named after the name of the parent carboxylic acid, the acid uo-at-il is converted into chloride.


b) Preparation of Acid Chloride

Hydrochloric acid can be obtained directly from the parent carboxylic acid by reaction with thionyl chloride (SOCl2) or other penghalogen substances, such as PCl3.

c) Acid Chloride Reactions

Acid halide is most reactive carboxylic acid derivatives among all. Therefore, when bound to the positive carbon of the carbonyl group, this ion ditukargantikan easier than when bound to the alkyl carbon.

1) The reaction with alcohol

Hydrochloric acid reacts with alcohol to produce ester and HCl in a hydrolysis reaction directly beranologi. Usually HCl immediately removed from the reaction mixture after forming, and pyridine hydrochloride was added as a sweeper.

2) The reaction with ammonia and amines

Organic products of the reaction is an amide.
3) The reaction with organometallic compounds

An acid chloride reacts with a variety of nucleophiles, including organometallic compounds. Such as Grignard reagents.

B. Carboxylic acid anhydride

Anhydride acid has two carboxylic acid molecules in which a water molecule is eliminated. (Anhydride means "a compound without water"). [6] For example, two molecules of ethanoic acid and then removing the water molecules obtained ethanoic anhydride (old name: acetic anhydride).

a) The name Tata anhydride

Symmetrical anhydrides are named by adding the word anhydride in front of the name of the parent carboxylic acid.

IUPAC: ethanoic acid anhydride propanoic acid anhydride

Trivial: acetic acid anhydride propionic acid anhydride

b) Preparation of Anhydride

One of the exception, not acid anhydride can be formed directly from the parent carboxylic acid, but must be prepared from carboxylic acid derivatives are more reactive. There are two ways of making anhydride, the first using a chloride and a carboxylic acid. The second by processing the carboxylic acid and acetic acid anhydride, the reaction is reversible. The location of the equilibrium can shift to the right to distill acetic acid as soon as these acids are formed.

c) reaction of anhydride

Acid anhydride having the same reaction as the acid halide, but the reaction was slower. Mechanism for nucleophilic substitution reaction of anhydride with a reaction to the acid halide.

Reaction with alcohols or phenols

C. Carboxylic Acid Esters

Esther is one of the very useful organic compounds, can be converted into a diversity of other compounds. Ester is an organic compound formed by replacing one or more hydrogen atoms on the hydroxyl group with an organic group. Esters are often found in nature such as fats and waxes. Volatile esters resulted in a lot of fruit and perfume.

Nama, bau, dan titik didih
Nama trivial	Struktur	Bau	T.d.˚C
metil asetat	CH3CO2CH3	enak	57,5
propil asetat	CH3CO2CH2CH2CH3	seperti buah pear	102
isobutil propionat	CH3CH2CO2CH2CH(CH3)2	seperti rum	137
metil salisilat		seperti gandapura (wintergreen)	220

Synthetic flavors can rarely match the actual natural flavor.

a) The Tata name Esther

The name of an ester composed of two words of the first name of the alkyl groups attached to the oxygen ester, the latter derived from the name karboksilatnya acid, omitting the word acid (english:-ic acid to-ate).

IUPAC: sodium propanoate propanoic acid methyl propanoate

trivial: propionic acid methyl propionate sodium propionate

b) Preparation of Esters

Various methods for synthesizing ester.

Of carboxylic acids and alcohols

c) Ester reactions

In acid solution, the carbonyl oxygen of an ester can be diprotonkan. Then the partial positively charged carbon, can be attacked by weak nucleophiles such as water.

When an alkaline solution, an ester carbonyl carbon is attacked by a nucleophile apat good without prior protonation. Addition-elimination path is the same as those for hydrochloric acid and anhydride.

1) lactone

Hydroxy acids contain two functional groups are required in the manufacture of esters. If both groups can come in contact with the bending of the two chains are able to react with each other to form cyclic esters called lactones. For example: [10]

Carboxylic acid hydroxyl groups in α or β position is not easy to form a cyclic lactone normally produced because it would strain the ring with a hydroxyl group while further from the γ or δ position not only form a lactone but lactone hydroxy acids can be synthesized as used for esterification. Esterification by using a dilute solution of hydroxy acid in a solvent slow (inert), if it is used it will produce a concentrated solution of polyester.
2) Polyester

Polyester is a category of polymer (a chain of repeated units) which contain the ester functional group in its main chain, although there are many polyesters, the term "polyester" is a specific material is more often referred to PET. Polyesters include chemical substances that are natural and synthetic chemicals that have many uses.
Manufacture of polyester as an example of which is made from the condensation polymerization reaction involving a 2-COOH group and an alcohol with two-OH groups

then we form the compounds of the above in turn and make the ester. Wherein each of the second group of one molecule of water is lost each time a connection is established. [13]

can also be written without a separate bonding rangkapC = O-

4. Amide

Amide is a derivative of a carboxylic acid least reactive, amides of the most important is the protein. An amide of carboxylic acids are named by replacing the suffix-or oat-at of the name with the suffix acid amides.

Example:

IUPAC: metanamida etanamida

trivial: formamide asetamida

1) Barbiturates

Commonly used as a sedative (winner), is a cyclic amide having various substituents on the carbon.

2) Urea

Use of fertilizers and basic materials for the synthesis of polymers and drugs, including barbiturates. Close to the carbamate compounds, compounds containing amide-ester group, obtained in medicines and insecticides.

5. Polyamide

Examples of polyamides are the most important is protein. Examples of man-made polyamide is polyamide synthetic nilon6, 6 which is made from adipic acid (an acid bi) and heksametilenadiamina (a diamida) as a reaction to the polyester. [16]

6. Nitrile

Nitrile is an organic compound containing a double 3 between the carbon and nitrogen. The nitrile functional group is a cyano group.

a) The Tata name of the nitrile

In the IUPAC system, the number of carbon atoms determines the parent alkananya, alkane name is given the suffix-nitrile. Giving a name to replace the acid-uo at a suffix-nitrile, or-onitril. [17]

IUPAC: etananitril benzenakarbonitril

trivial: acetonitrile benzinitril

b) reaction of nitrile

Nitriles can be hydrolyzed by heating with aqueous acid or base.

D. Use of Derivatives in the Synthesis of Carboxylic Acid

Carboxylic acid derivatives can be converted one into the other is synthetic. The most perfect of the halide derivatives asthma carboxylic acids and anhydrides, because both are more reactive than other carbonyl compounds.

a) acid halides and anhydrides can be used to synthesize esters of unimpeded

b) useful in the synthesis of esters and alcohols are valuable starting materials in synthesizing complex molecules.

c) Synthesis of nitriles to extend the carbon chain aliphatic chain with one another, or to add a carboxyl group or a group NH 2.