تفاعل #50029
ord-bcac725e8d74422aad39a80a0f9d319a
معادلة التفاعل
الكواشف
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المعالجة
- 1workup.ADDITIONdropped below 10%
- 2أخرىwas lowered to 0° C.
- 3أخرىreached 30° C.
- 4أخرى(about 10 min)
- 5ترشيحthe suspension was filtered over a pad of celite
- 6workup.ADDITIONThe filtrate was reintroduced into the reactor
- 7workup.DISTILLATIONthe methanol was distilled off at a pressure of 90-160 mbar
- 8أخرىa jacket temperature of 50° C
- 9workup.ADDITIONEthyl acetate (53 L) was then added
- 10workup.STIRRINGwith stirring
- 11درجة الحرارةthe mixture cooled to 0° C.
- 12workup.STIRRINGthe mixture stirred for 16 hr
- 13أخرىUnreacted pyroglutamic acid crystallized out
- 14أخرىwas removed by filtration
- 15أخرىRemoval of the ethyl acetate
- 16أخرىby evaporation under reduced pressure
الإجراء التجريبي
Methanol (62 L, 1.155 mol), L-pyroglutamic acid (20 kg, 154.9 mol) and H2SO4 (97%, 0.87 L, 15.5 mol) were introduced into a reactor. The suspension was warmed to 60° C. and stirred until the pyroglutamic acid concentration dropped below 10%. The temperature of the reactor jacket was lowered to 0° C., and when the internal temperature reached 30° C., 9.7 kg (68.1 mol) of Na2SO4 was added and stirred for 15 min, then 8.1 kg (96.4 mol) of NaHCO3 was added. When pH 7 was reached (about 10 min), the suspension was filtered over a pad of celite. The filtrate was reintroduced into the reactor, and the methanol was distilled off at a pressure of 90-160 mbar and a jacket temperature of 50° C. Ethyl acetate (53 L) was then added with stirring, the mixture cooled to 0° C., and the mixture stirred for 16 hr. Unreacted pyroglutamic acid crystallized out and was removed by filtration. Removal of the ethyl acetate by evaporation under reduced pressure provided the title product as a viscous yellow oil, which was taken to the next step without further purification.