Preparation of 2,4,6-tri-isobutyl dihydro-1,3,5-dithiazine

A process for producing crystalline 2,4,6,-tri-isobutyl-dihydro-1,3,5-dithiazine having the structure:

• ##STR11## comprising the steps of:
• (i) reacting isovaleraldehyde with ammonium sulfide in the presence of citric acid in aqueous media a temperature of between 0.degree. C. and 15.degree. C. with the mole ratio of ammonium sulfide:isovaleraldehyde being between 2:1 and 1:0.5;
• the reaction time being between one and five hours thereby forming a gel;
• (ii) converting the resulting reaction mass gel to a two-liquid phase system;
• an organic phase and an aqueous phase by means of mechanical agitation of said gel;
• (iii) separating the aqueous phase from the organic phase;
• (iv) admixing the organic phase with aqueous mineral acid whereupon a crystalline precipitate is formed;
• (v) separating the resulting crystals from the resulting mixture;
• (vi) washing the resulting crystals with a non-dissolving hydrocarbon liquid;
• (vii) neutralizing the resulting washed crystals by dissolving said crystals in a solvent and admixing the resulting solution with a weak base;
• (viii) washing out the excess base from the resulting solution and drying the resulting organic solution;
• (ix) evaporating the solvent from said organic solution to yield 2,4,6-tri-isobutyl-dihydro-1,3,5-dithiazine in crystalline form.