Kamis, 31 Mei 2012

Judging from its structure carboxylic acid derivatives are compounds derived from the turn of the-OH group in the structure of the formula RC-OOH by the group X (halogen),-NH 2 OR ', or-OOCR. Each replacement of an acyl group of compounds of different nature and a row is called the acid halide (R-COX), amides (RCONH2) ester (RCOOR '), and carboxylic acid anhydride (RCOOORCR).As well as carboxylic acids, acid derivatives karbosilat also differentiated into derivatives of aliphatic or aromatic carboxylic acids, both substituted maupaun are not substituted. All carboxylic acid derivatives having acyl functional group (RCO-) or aroil (ARCO-) and when hydrolyzed produce carboxylic acids. Side results in the hydrolysis of the type of acid derivative tergatung karboksilatnya.The existence of the carbonyl group in carboxylic acid derivatives led to the molecule is polar. This polarity which affects the physical properties and chemical carboxylic acid derivatives.

NomenclatureAmide is a compound having a trivalent nitrogen bonded to a carbonyl group. In the amide compound, gugusfungsi acyl-NH2 group relates to. In giving his name, the suffix-At-Oat or in the name of the parent acid is replaced with an amide.Example:HCOOH: metanoat acid / formic acidHCONH2: metanamida (IUPAC)Formamide (nontrivial)CH3CH2CH2COOH: bityanoat acid / butyric acidCH3CH2CH2CONH2: butanamida (IUPAC)Butiramida (nontrivial)
Physical properties SifarPolar molecules of carboxylic acid derivatives of compounds caused by adanaya carbonyl group (-C-), affects the physical properties (boiling point, melting point and solubility) note that titij boiling acid halide, carboxylic acid anhydride and the ester is almost the same almost the same with aldehydes and ketones boiling titk a comparable molecular brat. Keep in mind that the aldehydes and ketones are compounds which also contain carbonyl groups. Especially for the amide compound, the price was high enough boiling point. This is caused by inter-molecular hydrogen adanyai Katan described as follows:RH CO ... N - H .... O N - HC HR
All dapay carboxylic acid derivatives soluble in organic solvents, whereas the water solubility depending on the number of carbon atoms contained in the molecule. For example, for the ester group of compounds containing 3-5 C atoms are soluble in water, but for the amide group of compounds that are soluble in water which has a 5-6 atom C.Various volatile esters have pleasant odors that are often used in the manufacture of perfumes or synthetic flavoring ingredient. Acid chloride group of compounds having a sharp odor because it is easily hydrolyzed and produce carboxylic acid and HCL which each have a distinctive odor.


Chemical propertiesIn studying the chemical properties of each group of carboxylic acid derivatives, it must first be understood. General characteristics of the reaction as described below:The presence of carbonyl group in carboxylic acid derivatives determine the reactivity of the reaction, although the carbonyl group is not changed.Acyl group (RC = O), causing carboxylic acid derivatives susceptible to nucleophilic substitution. In this substitution, atom / group associated with the acyl group was replaced by another group which is alkaline. General pattern of nucleophilic substitution reactions are written by the equation


Nucleophilic substitution reactions on carboxylic acid derivatives is faster than the nucleophilic substitution reactions at saturated carbon chain (alkyl group), and thus



Description of AmidaAmide is a compound that is karbosilat acid derivatives obtained from the replacement of-OH to-COOH group by group-NH ¬ 2. Thus Dsngan general formula for the amide is
Amida PembutanAmide prepared by reacting ammonia on the acid chloride or acid anhydride, while the industry is made by heating ammonium carboxylate salts.Example:



The reactions of amidesHydrolysisAn amide hydrolysis can take place under acidic or basa.Dalam acidic environment, the reaction occurs between the water that has been protonated amide and produce the carboxylic acid-NH 3 ¬ ¬
In alkaline environment, OH-attack on the amide and carboxylic acid anions produce NH3 +Preparation of imideA cyclic anhydride anhydride as the others, can react with ammonia, but the reaction contains two kinds of groups, namely group-CONH2 and COOH groups. When the reaction is heated, the release of one water molecule and form an imide.

1 komentar:

  1. would you like tell me why Nucleophilic substitution reactions on carboxylic acid derivatives is faster than the nucleophilic substitution reactions at saturated carbon chain (alkyl group)?

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