Product name: 3-mercaptopropionic acid

CAS Number: 107-96-0

Assay: 99.0% min

Molecular Formula:C3H6O2S

Molecular Weight:106.14

Hs Code: 29309070

3-Mercaptopropionic acid is the direct raw material of the organic chemical industry, used in pharmaceutical intermediates and electronic chemicals; it is used as an intermediate of pharmaceutical fennarol, and also used as a stabilizer for polyvinyl chloride. Like thioglycolic acid, it can be used in transparent products. It has very good thermal stability and is superior to other stabilizers; it is also used as an antioxidant, catalyst, and biochemical reagent.

After nearly 30 years of development, the downstream pharmaceutical intermediate industry of mercaptopropionic acid has become an emerging industry with an output value of billions of yuan. With the development of the pharmaceutical industry, there will be new demands for pharmaceutical intermediates. At present, the pharmaceutical intermediates with relatively large demand in China are still traditional series of products such as aminothioxamic acid, demethylaminothioxamic acid, and their derivatives.

It has become a general trend to transfer the production capacity of downstream electronic chemicals of mercaptopropionic acid to China. From a regional perspective, the Asia-Pacific region, especially China, has become the leading market for the global electronics industry and its chemicals. As a pharmaceutical intermediate and raw material for electronic chemicals, mercaptopropionic acid will increase in demand and have a promising market prospect.

Mercaptopropionic acid is an intermediate of the medicine fenarimol, and it can also be used to prepare crosslinking agents, hardeners, resin additives, antioxidants, catalysts, and biochemical reagents, and can also be used as a raw material for PVC heat stabilizer ester-based tin.    

The preparation method of 3-mercaptopropionic acid:          

Step 1:Addition reaction

Operation process:

Add NaHS aqueous solution, NaOH, and sulfur powder into the reaction kettle in sequence, start stirring, heat up to 45°C, and keep it warm for 1 hour, then set aside.

Accurately weigh the acrylonitrile, vacuum pump it into the high-level metering tank, and open the airflow N2 to discharge the air in the kettle. After about 10 minutes, continue to maintain a small flow of N2, and start to slowly add it to the above reaction solution to control the system. The inner temperature is 45-50°C, the dripping is completed in about 1.5 hours, and then the reaction is kept at 50°C for about 3 hours under the protection of N2, and the mixture solution of 3-mercaptopropionitrile and dithiomalononitrile is obtained when it is lowered to room temperature.

Step 2:hydrolysis reaction

Operation process:

Pour the measured amount of hydrochloric acid into the reaction kettle, close the vent valve, open the absorption tower and the reaction kettle, start stirring, slowly add the reaction solution of step 1 dropwise at the specified 50°C, and after about 3 hours of titration, quickly raise the temperature to reflux, After 3 hours of reflux reaction, the temperature was lowered to 80-90°C to obtain a mixture solution of 3-mercaptopropionic acid and dithiomalonic acid.

Step 3: Reduction reaction

Operation process:

Step 2: After the temperature of the reaction solution drops to 80-90°C, open the feeding port and evenly add the metered iron powder. The addition is completed in about 1.5 hours. Under the conditions, keep the reaction at 80-90°C for 2 hours, then drop it to below about 40°C, and filter. The liquid was transferred to the extraction tank, the solid was rinsed with toluene, and the obtained toluene liquid was transferred to the extraction tank together, then extracted with toluene, the toluene layers were combined, and the toluene was recovered by distillation to obtain the crude product of 3-mercaptopropionic acid.

Step 4: refining process

Operation process:

The crude product of 3-mercaptopropionic acid is rectified under reduced pressure, and the fraction at 100-102°C under 665 Pa is collected to obtain the finished product of 3-mercaptopropionic acid.