Chemical properties,  applications, and production methods of Methylene Blue

Methylene blue (MB) is a reducing agent that is soluble in water, easily penetrates cell membranes, and has relatively no side effects. It is an approved clinical medication. Since its introduction into the field of biology in the 19th century, methylene blue has been widely used: methylene blue has been used as a dye in neurochemical anatomy and bacteriology; In biochemical research, methylene blue serves as an indicator of redox reactions. As an antidote, methylene blue is used to treat methemoglobinemia caused by poisoning such as nitrite;

English name: Methylene Blue

CAS number: 61-73-4

Molecular formula: C16H18ClN3S

MW：319.85

EINECS number: 200-515-2

Chemical property

Gold red glittering gold yellow or antique copper colored powder. Soluble in water, blue in color, slightly soluble in ethanol. The dye turns yellow green in concentrated sulfuric acid and turns blue after dilution. The aqueous solution with sodium hydroxide turns purple and produces dark purple precipitates.

Application：

1.Mainly used for dyeing cotton, acrylic, linen, and silk, with poor fastness and a sun fastness of 2-3 levels. It is also used for paper dyeing, bamboo and wood coloring, as well as ink and lake manufacturing. It can also be used for staining biological bacterial tissues.

Technical indicators:

2.A non-toxic dye that appears blue in the oxidizing form and colorless in the reducing form. When staining live yeast cells, due to cellular metabolism, the cells have strong reducing ability, which can cause methylene blue to change from a blue oxidizing form to a colorless reducing chemicalbook form. However, when the metabolism is weak or dead cells have no such reducing ability or extremely weak reducing ability, methylene blue is dyed blue or light blue. This method can not only observe the morphology of yeast cells, but also be used to distinguish dead and live yeast cells.

Production method：

1. Nitration is carried out on N, N-dimethylaniline, which is reduced to form p-aminodimethylaniline. It is then oxidized, sulfurized, and condensed with sodium dichromate and sodium thiosulfate. The final product is obtained by salt formation, salt precipitation, filtration, and drying with zinc chloride. Raw material consumption (kgChemicalbook/t) N, N-dimethylaniline 790 sodium nitrite 250 sulfuric acid 760 hydrochloric acid (31%) 500 sodium dichromate (95%) 1400 sodium thiosulfate 830 refined aluminum sulfate 1060 copper sulfate 52 zinc chloride 372 iron powder 650.

   
   

2. Using N, N-dimethylaniline as the main raw material, p-aminodimethylaniline is first reduced by nitrite, then oxidized by Na2Cr2O7.Na2S2O3, sulfurized, and condensed to obtain thiazide. Finally, ZnCl2 is used to form salt, which is then salted out, filtered, and dried to obtain the final product.