Background and overview

3-Mercaptopropionic acid, the appearance is colorless or light yellow transparent liquid. It is the direct raw material of organic chemical industry, used in pharmaceutical intermediates, electronic chemicals, also used as stabilizer of polyvinyl chloride, and also used as antioxidant, catalyst and biochemical reagent. It can be used in transparent products like thioglycolic acid, and has very good thermal stability, better than other stabilizers; it is also used as antioxidant, catalyst and biochemical reagent.

Preparation

Weigh acrylic acid (8.0mmol, 0.5765g), add bis(2-dimethylaminoethyl)ether & bistrifluoromethylsulfonimide  Ionic liquid (0.80mmol, 0.2819g), reacted for 12h in an ethylene glycol bath at 70°C. After the reaction is over, cool to room temperature, add 5 mL of deionized water for liquid-liquid extraction, collect the supernatant after standing for 20 minutes, and repeat three times to ensure that the product 3-mercaptopropionic acid does not remain in the lower phase, that is, the ionic liquid phase. The upper product phase and the lower ionic liquid phase are dried separately, and the upper phase is analyzed by GC. The conversion rate is 97%, and the selectivity is 99%; the lower phase is a fresh ionic liquid, which can be refilled to the H2S catalytic activation stage for recycling. The crude 3-mercaptopropionic acid is further purified and subjected to a silica gel chromatography column, and the ethyl acetate and petroleum ether system is used for development and the product is collected. The ethyl acetate and petroleum ether can be recovered by distillation for the next use. The yield of the purified 3-mercaptopropionic acid product was 95%, and the product was analyzed by GC, and the purity of the product was 97%, which was determined to be the target product by nuclear magnetic characterization.

Use

Can be used to prepare 3-mercapto-1-propanol

50ml of tetrahydrofuran, 10.6g of 3-mercaptopropionic acidWas added to the reaction vessel, 5.7g sodium borohydride was added portionwise at 10 ~ 20 ° C, stirring constantly, sodium borohydride dropping complete successorContinued stirring for 30 minutes, then at this temperature 11.5 g of boron trifluoride tetrahydrofuran solution was slowly dropped; warmed to 35 ° C and maintained5 hours, then warmed to 50 ° C and held for 1 hour until the reaction mixture became a solid, cooled to room temperature, 30 ml of water was added slowly and then steamedTetrahydrofuran was distilled off, the rest of the mixture was added 9.1g hydrochloric acid (33% wt), adjusting the pH to 2 ~ 3; 20ml chloroform was added and stirred, pumpingThe filter cake was recrystallized to obtain boric acid crystals, the filtrate was separated by a separatory funnel; the aqueous phase was extracted twice with chloroform again, extracted three timesLiquid combined, atmospheric distillation to 100 ° C and collected chloroform, after cooling negative pressure (vacuum 0.095MPa) distillation, steam temperature 90 ~100 , 3-mercapto-1-propanol finished product (colorless transparent liquid), yield 81.5%, purity 99.3%.

Can be used to prepare methyl 3-mercaptopropionate

Chlorotrimethylsilane (276 mL, 2.18 mol) was added slowly to a solution of 3-mercaptopropionic acid (70 g, 0.66 mol) in methanol (267 mL, 6.6 mol) at -10° C. The reaction mixture was then stirred for 1 h at 0° C. and for 1 h at room temperature. The mixture was neutralized with saturated aqueous sodium bicarbonate to pH 8 and extracted with dichloromethane (3×300 mL). The combined organic phase was washed with saturated aqueous sodium bicarbonate (2×200 mL), brine (2×200 mL), dried over magnesium sulfate, filtered and evaporated under reduced pressure. The residue was then distilled (70° C./20 mmHg) to give methyl 3-mercaptopropionate as a colorless oil (61.2 g) in the yield of 77%.

Can be used to prepare other pharmaceutical intermediates or electronic chemicals

References

【1】 CN112745252,2021, A

【2】CN106748930,2017, A

【3】US2005/49234,2005,A1