2-Mercaptobenzothiazole (MBT) is an organosulfur compound with the formula C6H4NSCSH. The molecule consists of a benzene ring fused to a 2-Mercaptothiazole ring.
MBT chemical has a slightly foul odor and bitter taste, non-poisonous. Easily soluble in ethyl acetone, acetone, dilute solution of sodium hydroxide and sodium carbonate, soluble in ethyl alcohol, not easily soluble in benzene, insoluble in water and gasoline.
CAS No.: 149-30-4
Molecular Weight: 167.24
Molecular Formula: C7H5NS2
|Appearance||grayish-white or light yellow powder|
|Active content, %||99.0 Min.|
|Melting point, ℃||171.0 Min.|
|Heating loss, %||0.40 Max.|
|Ash content, %||0.30 Max.|
|Residue (150um), %||0.10 Max.|
There are a number of preparation methods for Mercaptobenzothiazole. But mainly the following three methods are used most in preparation and manufacturing.
Aniline, carbon disulfide, and sulfur are added to the high-pressure autoclave for direct reaction. And it also can use fatty amine, dimethylformamide, trithiazolidine, and poly tetrafluoro formaldehyde instead of carbon disulfide. To make aniline and sulfur react under high pressure.
With aniline as raw material, the reaction pressure is generally 4 MPa to 15 MPa. So it is also called the high-pressure method.
O-nitrochlorobenzene can be reduced to o-thiophenol by reacting with reducing agents sodium hydrogen sulfide, sodium polysulfide or hydrogen sulfide.
Further reaction with carbon disulfide to produce mercaptobenzothiazole. this method sometimes takes longer reaction time (about 20h for sodium hydrosulfide), but all can be carried out at atmospheric pressure or lower pressure. Also known as atmospheric pressure method.
The reaction pressure of this method is between the two previous methods. The pressure is below 4MPa. Also known as medium pressure method.
The preparation method is based on o-chloronitrobenzene, sodium polysulfide, and carbon disulfide as raw materials. At 110-130℃ temperature and 343kPa pressure, the reaction produces 2-mercaptobenzothiazole sodium salt. Then the product is obtained by acidification and water washing with sulfuric acid.
It can also be reacted with aniline, carbon disulfide, and sulfur at about 200°C. Then at 7.85 MPa pressure and 250-260 ℃ holding 2.5 h. That is 2-mercaptobenzothiazole.
Dissolve with sodium hydroxide to sodium salt. Then adjust the pH value to pH=9 and filter. The filtrate is then acidified and neutralized at 38-40°C, washed and dried to obtain the 2-mercaptobenzothiazole.
Add aniline, carbon disulfide, and sulfur yellow to the condensation kettle in turn. The feeding ratio is (mol) 1: 0.96: 0.36. The condensation reaction is finished after 2h at 8.1MPa and heated to 260℃. The crude product of 2-mercaptobenzothiazole was obtained. Cool down and transfer it to the neutralization kettle. Add alkali solution to neutralize, filter, and discard impurities. The filtrate is transferred to the acidification kettle, acidified with sulfuric acid to pH 6~7, and filtered. The filter cake is washed twice with water, dried, crushed, and packed by sieving to get the finished 2-mercaptobenzothiazole.
MBT chemical is used in the vulcanization of rubber.
Using mercaptobenzothiazole, rubber vulcanizes with less sulfur and at milder temperatures. Both factors give a stronger product. This effect was reported in 1921 by workers at Pirelli and at Goodyear Tire & Rubber.
Mercaptobenzothiazole is used as a cooling tower biocide. MBT chemical has also been used in the past in the gold-mining industry to “float” the gold from ore residue as part of the extraction process.
2-Mercaptobenzothiazole is a Hemi-ultra accelerator, extensively used in the vulcanization of natural and synthetic rubbers. It is mainly used in the manufacture of rubber tires, rubber belts, rubber shoes, and other technical rubber goods.
In addition, 2-Mercaptobenzothiazole is also used in the preparation of pesticide fungicide, nitrogenous fertilizer synergist, cutting oil and lubricating additives, photographic chemistry in the machine anti ash agent, metal corrosion inhibitors, etc. It is also a reagent used in chemical analysis.
This product is one of the effective corrosion inhibitors of copper or copper alloy. When the cooling system contains copper equipment and raw water contains a certain amount of copper ions, can be added to prevent copper corrosion.
2-mercaptobenzothiazole is also an intermediate of the herbicide benzothiachlor.
In the plastic bag or kraft paper bag. 25 kg per bag or customers’ requirements. The storage environment should be ventilated, cold, and dry. Separate from food materials, acids, and oxidizers in the warehouse. It is low in toxicity and has an irritating effect on the skin and mucous membranes.