(Hive Bee)
02-04-03 14:37
No 404486
      Peracetic acid synthesis according d'Ans
(Rated as: excellent)

Berichte der Deutschen chemischen Gesellschaft 45 (1912) 1845-1853.

237. J d'Ans and W Frey: Direct synthesis of organic peracids [Direkte Darstellung organischer Persaeuren.]

[...] To synthesize peracetic acid, 1 mol acetic anhydride is carefully (via cooling with ice water) reacted with 1 mol hydrogen peroxide in the presence of 1% sulfuric acid.
At the beginning of the reaction process, acetic anhydride will react violently with H2O2. If the reaction mixture is too cold, the reaction might postpone to give a sudden more violent reaction once the right temperature has been reached. Addition of sulfuric acid and/or H2O2 to the mixture of CH3COOOH and CH3COOH does not result in an important exothermic reaction. The mixture is allowed to rest for 12 hours.
At its equilibrium @ 14.6 C, the mixture contains 68.3% peracetic acid and 8.08% H2O2. If the mixture is distilled at 20-30 C (10-20 mmHg), peracetic acid concentrations of ca 78% can be be obtained. The distillate residue consists of unreacted H2O2 and traces of peracid. Generally, the obtained peracid yields are good. A selection of performed syntheses:
A solution (165.0 g) in equilibrium contained 73.8% peracetic acid and 13.97% H2O2 (2% sulfuric acid had been applied). 139 g of the distillate consisted of 105.8 g peracetic acid and 2.2 g H2O2. The residue (17.4 g) contained 4.1 g peracetic acid and 8.3 g H2O2. Consequently, the resulting peracetic acid solution was 76.15%.
When the sulfuric acid concentration is increased, the peracid formation equilibrium will move in favour of peracetic acid. At 14.6 C, 1 mol acetic acid, 1 mol H2O2 and 1% sulfuric acid will result in a 51.5% peracetic acid solution, while the concentration will be 54% peracetic acid when 3% sulfuric acid is used.
Applied: 100 g acetic anhydride + 68.15 g H2O2 (98.45%) + 22.35 g H2SO4 ( = 190.5 g). Yield: distillate 147.56 g containing 129.79 peracetic acid and 0.54 g H2O2. 38.67 g residue containing 14% peracetic acid and 6.02% H2O2. The distilled peracetic acid solution was consequently determined to be 88%. Further fractional distillation resulted in a more pure product, but we never obtained a 100% pure end compound.[...] Substitution of sulfuric acid for H3PO4 didn't yield satisfactory results.
Peracetic acid is a colourless liquid, MP 0.1 C. It is extremely explosive. When it is heated slowly, it will explode extremely violently at ca 110 C. The boiling point might be around this range. Peracetic acid mixes with water, alcohol, ether, sulfuric acid and is well preserved in aquatic solution, as long as it is diluted and free from impurities. Salts, acids and bases will stimulate hydrolysis into acid and H2O2. The odour is very pungent. [...]

Another one to add to you collection of peracid synthesis routes... Not much new I guess, but hey, better too many articles then too few wink.
The article also mentions the synthesis of other peracids, as there are perpropionic and perbutyric acid, and performic acid. All very similar to the translated part, but on a massive amount of requests, I'll add these descriptions as well tongue.

Abusus non tollit usum