Method for purifying rubber vulcanization accelerator MBT (2-mercaptobenzothiazole)

The invention discloses a method for purifying a rubber vulcanization accelerator MBT (2-mercaptobenzothiazole). The method comprises the following steps: completely dissolving crude M by using a sodium hydroxide solution with the weight concentration of 30%, controlling the final pH of the sodium salt solution to be 9.5, adding deionized water to dilute, controlling the weight concentration of the sodium salt solution to be 3-8%, blowing and oxidizing for 1.5-2.5 hours, dropwise adding a sulfuric acid solution with the weight concentration of 1-3% at the speed of 1-3L/min at the same time till the pH is 9 and the solution is clear and transparent, filtering, heating the sodium salt solution to 25-95 DEG C till a clear and transparent state is achieved, dropwise adding a sulfuric acid solution with the weight concentration of 5-10% to neutralize till the pH is 5-7, filtering, dewatering, washing and drying the solid to obtain the finished product MBT. The method disclosed by the invention has the advantages that the method is simple in process and easy in industrialization; the purity of the prepared high content MBT is up to more than 99%.