Ethyl 2-cyano-3-methylbutanoate → 2,3-Di(propan-2-yl)butanedioic acid

With reference to FIG. 3, a preferred embodiment of the invention will be described below, wherein diethyl 2,3-diisopropylsuccinate is obtained. Absolute ethanol and metallic potassium are charged into a reactor R101, or potassium ethoxide and absolute ethanol are charged into the reactor R101, to prepare a solution of potassium ethoxide; ethyl 3-methyl-2-cyanobutyrate is charged into a reactor R102, and then the prepared solution of potassium ethoxide is added thereto at a temperature ranging from −10° C. to 45° C.; upon the completion of the reaction, the reaction mixture is transferred to a reactor R103 and the solvent is removed, then tetrahydrofuran or acetonitirle is added thereto, followed by the addition of ethyl 2-bromoisopentanoate, and then the reaction mixture is heated to reflux; upon the completion of the reaction, the solvent is removed again, the resultant mixture is transferred to a separator R104, water is added thereto to dissolve solids, and the mixture is extracted with diethyl ether or methyl tert-butyl ether; the extract liquor is passed through a drying column T101 so as to be dried, and then is fed to a separating column T102, where diethyl 2,3-diisopropyl-2-cyanosuccinate is separated; the diethyl 2,3-diisopropyl-2-cyanosuccinate is added into a reactor R201, and a 60-90% aqueous solution of sulfuric acid is added dropwish thereto to conduct hydrolysis and decarboxylation reaction; upon the completion of the reaction, the reaction mixture is diluted with water and transferred to a separator R202 to be extracted with methyl tert-butyl ether; the obtained methyl tert-butyl ether extract liquor is charged into a reactor R203, and an aqueous solution of potassium hydroxide is added thereto; then the reaction mixture is transferred to a separator R204 to be separated; an aqueous layer separated is acidized with hydrochloric acid in a reactor R205 to obtain precipitates; the precipitates are centrifugally dried in a centrifuge C201, and then dried to afford 2,3-diisopropylsuccinic acid; the 2,3-diisopropylsuccinic acid and absolute ethanol are charged into a reactor R301, and a catalytic amount of sulfuric acid is added thereto, to conduct esterification reaction; upon the completion of the reaction, the ethanol is removed, and methyl tert-butyl ether is added into the reaction mixture; the resultant mixture is transferred to a separator R302 and wished with an aqueous solution of sodium bicarbonate; the organic layer is passed through a drying column T301 so as to be dried, and then is fed to a reactor R303, where the solvent is removed to obtain a crude product; the obtained crude product is fed to a separator R304, wished there with an aqueous solution of potassium hydroxide, and extracted with methyl tert-butyl ether; the extract liquor is dried in a drying column T302, and then fed to a reactor R305, where the solvent is removed to obtain diethyl 2,3-diisopropylsuccinate.

1. customis obtained
2. additionare charged into the reactor R101
3. customranging from −10° C. to 45° C.
4. customupon the completion of the reaction
5. customthe reaction mixture is transferred to a reactor
6. customR103 and the solvent is removed
7. additiontetrahydrofuran or acetonitirle is added
8. additionfollowed by the addition of ethyl 2-bromoisopentanoate
9. temperaturethe reaction mixture is heated to reflux
10. customupon the completion of the reaction
11. customthe solvent is removed again
12. additionis added
13. dissolutionto dissolve solids
14. extractionthe mixture is extracted with diethyl ether or methyl tert-butyl ether
15. customso as to be dried
16. customis separated
17. additionthe diethyl 2,3-diisopropyl-2-cyanosuccinate is added into a reactor R201
18. additiona 60-90% aqueous solution of sulfuric acid is added dropwish
19. customhydrolysis and decarboxylation reaction
20. customupon the completion of the reaction
21. extractionto be extracted with methyl tert-butyl ether
22. extractionthe obtained methyl tert-butyl ether extract liquor
23. additionis charged into a reactor R203
24. additionan aqueous solution of potassium hydroxide is added
25. customto be separated
26. customan aqueous layer separated
27. customis acidized with hydrochloric acid in a reactor
28. customR205 to obtain
29. customprecipitates
30. customthe precipitates are centrifugally dried in a centrifuge C201
31. customdried

ORD record

ord-9ab05a5076ed406894b08f665378af2d

Source dataset

uspto-grants-2014_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08669392B2