(Hive Bee)
07-06-04 09:45
No 517724
(Rated as: good read)
The following is a re-write of a procedure found in the book: "Laboratory Text in Organic Chemistry; Cason & Rapoport, 1950". If you can find this book I would highly recommend it. It contains quite a few valuable procedures for reagents and is written for students of the art. I decided to post this because the procedure works perfectly and produces a product of high purity. p-Tosic acid has proven to be a highly efficient catalyst in the baeyer-villiger oxidation, peracid oxidation..etc. of ketones and aldehydes. Depending on your precursor of interest: MDP2P, P2P.. the salt can be added in catalytic amounts which in some cases boost yields of product considerably.
Procedure:
Sodium p-toluenesulfonate. To a 125ml RB flask provided with an air condenser are added 11ml (9.3g) of Toluene and 10ml (18.5g) c.p. concentrated sulfuric acid. The mixture is heated in a boiling water bath with frequent (magnetic) stirring. When all the toluene has reacted (about 1/2 hour) as indicated by a homogeneous solution, the mixture is slowly poured, with stirring, into a beaker containing 75ml dH2O. After adding 25g of well-ground sodium chloride, the beaker is covered with a watch glass and heated until the salt is dissolved. The hot solution is filtered with gravity and the filtrate cooled to crystallize sodium p-toluenesulfonate (scratching the side walls with a glass stirring rod may be necessary to induce crystallization). The crystals/mother liquor are filtered with suction, the filter cake washed with 15-20ml cold alcohol. Drying is completed by placing the crystals on a watch glass on the steam bath. **CaCl2 dessicant works fine as well** If the material is impure (discoloration or presence of large amount of sodium chloride), it may be recrystallized by dissolving in 30ml dH2O, adding 10g sodium chloride, and heating and stirring to bring the solid into solution (adding a little more dH2O if necessary). The solution is then stirred with about half a gram of decolorizing carbon and filtered with gravity, the minimum amount of hot dH2O being used as a rinse. Concentraion of the clear filtrate to about 30-35ml and cooling gives 6-8g of crystals, collected as described above. The product is sodium p-toluenesulfonate dihydrate.
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