In a 0.5L beaker, a slurry of tetrabutylammonium hydrogensulfate 34.0g (100 mmol) in ice cold water 50 mL was treated with 1M NaOH 101 mL and the mix was stirred until complete dissolution. (The pH of the solution was about 11-12, on indicator paper strip). While stirring with a large stainless steel spatula, aqueous 40% sodium permanganate solution 29mL (=39g, 110 mmol, Aldrich) diluted with cold water 50 mL was gradually added to the beaker and the obtained thick sludge was hand-stirred on ice bath for 20 min. During this time the produced blackberry-colored congealed mass became fine-grained and purple supernatants separated. The solids were collected on a large glass Buchner funnel (350mL, medium porosity), the cake was thoroughly compressed on the funnel, washed with ice-cold water (8x20mL) then fluffed up with a spatula again and washed with more ice-cold water (100mL). In the final washing stage, the produced washings were only light-purple. The solids were dried by air suction and then on highvac.
Y=35.78g (99%) of a bright violet powder.
Note 1: Drying this quantity of material on highvac took one full day. The product is best stored in a dark bottle in the fridge.
Note 2: I just put a small heap of the dried product to torch and it burned wickedly fast like gunpowder - with a puff.
Note 3: People inhaling manganese oxide dust or injecting themself with permanganate solution can develop a Parkinson-like irreversible CNS damage.