Polyester90.7 Polyester
Polyester can be made by reacting a diol (ethane-1,2-diol) with a dicarboxylic acids
(benzene-1,4-dicarboxylic acid). n HO-CH 2 CH 2 -OH + n HOOC-C 6 H 4 -COOH→ (-O-
CH 2 CH 2 -O-OC-C 6 H 4 -CO-)n+ n H 2 OPolyestermakesreasonable fibres, it is quiteinflexible
so it does not crease easily; but for clothing it is usually combined with cotton for comfort.
The plastic is not light-sensitive, so it is often used for net curtains. Film, bottles and other
moulded products are made from polyester.
90.8 Distinguishing carboxylic acids from phenols
Although carboxylic acids are acidic, they can be distinguished from phenol because: Only
carboxylic acids will react with carbonates and hydrogencarbonates to form CO2
2 CH 3 COOH + Na 2 CO 3 →2 CH 3 COONa + H 2 O + CO 2
C 6 H 5 COOH + NaHCO 3 →C 6 H 5 COONa + H 2 O + CO 2
Some phenols react with FeCl3 solution, giving a characteristic purple colour.
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