Reaktion #482016

Reaktionsgleichung

HCl

2-nitropropane

3,6-dichloro-2-methylbenzyl bromide

sodium methoxide

→

pure product

Ausbeute 94.3%

3,6-dichloro-2-methylbenzaldehyde

Ausbeute 94.3%

Lösungsmittel

water

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeis exothermic to 53° C.
2. 2
   Extraktionthe mixture is extracted three times with 1 l of ethyl acetate
3. 3
   Waschenwashed twice with 500 ml of saturated NaCl solution
4. 4
   Trocknendried over Na2SO4
5. 5
   Einengenconcentrated under reduced pressure
6. 6
   workup.DISTILLATIONthe 161.0 g of crude product are distilled
7. 7
   FiltrationThe crystals from the last fractions are filtered
8. 8
   workup.DISTILLATIONThe residue is distilled over a Spaltrohr column

Vorschrift

122.4 g (0.68 mol) of a 30% strength solution of sodium methoxide are dissolved in 1030 ml of methanol, and 56.4 g ( 0.57 mol) of 90% pure 2-nitropropane and 188.5 g (0.52 mol) of 61.6% pure 3,6-dichloro-2-methylbenzyl bromide are then added. The reaction is exothermic to 53° C., and the mixture is then stirred for 90 min. The reaction mixture is poured into 2.5 l of water, the pH is adjusted to pH 7.0 using 10% strength HCl, the mixture is extracted three times with 1 l of ethyl acetate, and the organic phases are combined, washed twice with 500 ml of saturated NaCl solution, dried over Na2SO4 and concentrated under reduced pressure: the 161.0 g of crude product are distilled using a 10 cm column packed with 10 mm Raschig rings. The crystals from the last fractions are filtered. This gives 9.8 g comprising 85.9% of the desired product and 4.5% and 6.9% of isomers. Yield: 9.7%. The residue is distilled over a Spaltrohr column, giving another 3.2 g of 94.3% pure product.

Quelle