A method for preparing a rod-shaped crystals of methylene blue

The present invention provides a method for preparing a rod-shaped crystals of methylene blue, technical field belonging to the chemical production of raw materials. First, calcium nitrate and diammonium hydrogen phosphate are dissolved in deionized water to obtain a solution A and B, so that the two calcium nitrate solution and diammonium phosphate molar ratio of 5: 3; and pH were adjusted with ammonia solution two value, and then added a solution in methylene blue solution B, and a was added dropwise to constantly stirred B containing methylene blue solution. After completion of the dropwise addition, the hydrothermal reaction for 4 hours with stirring, and then left to age for 12 hours. The reaction solution was finally sieved, washed with methylene blue were sieve and dried 12 hours at 40 ℃, i.e. the preparation of rod-shaped crystals of methylene blue, a length of 0.2 to 5 mm. The process of the method employed simple, low raw material prices and easy industrial production.