Esters
CnH2n+1COOCmH2m+1
This carbon compound
is a product of a chemical reaction between an alcohol and an
organic / carboxylic acid. The chemical reaction is known as
esterification. The presence of concentrated sulphuric acid is the
catalyst
for this reaction. The hydrogen of the
carboxyl group -COOH (of the acid)
is replaced by an alkyl. The name of an ester is a combination of
the alkyl and the carboxylate of the acid. An
example of an ester is ethyl ethanoate - which can be produced
from the reaction between ethanol and ethanoic acid.
Among the physical properties of esters include their low boiling point and a sweet smelling odour. These properties make esters suitable for the manufacture of fragrance (perfumes) and and food flavourings. The general formula for esters is shown above.
Among the physical properties of esters include their low boiling point and a sweet smelling odour. These properties make esters suitable for the manufacture of fragrance (perfumes) and and food flavourings. The general formula for esters is shown above.
Sebatian
karbon ini merupakan hasil tindak balas kimia di
antara alkohol
dengan asid karbosilik / organik. Tindak balas kimia ini
dikenali sebagai pengesteran. Kehadiran asid sulfurik pekat
merupakan mangkin bagi
tindak balas ini. Hidrogen
dalam kumpulan karboksil -COOH (daripada asid)
digantikan oleh suatu alkil. Nama ester merupakan gabungan
alkil dan bahagian karbosilat daripada asid.
Salah satu contoh ester ialah etil etanoat. Ia boleh
dihasilkan daripada tindak balas di antara etanol dan asid
etanoik.
Di antara sifat-sifat fizikal ester termasuk takat
didih rendah dan baunya yang harum. Sifat-sifat ini menjadikan
ester sesuai untuk pembuatan minyak wangi dan perasa makanan.
Formula umum dipaparkan di atas.