Title:
METHOD FOR PREPARING DL-PROLINE
Document Type and Number:
WIPO Patent Application WO/2021/253306
Kind Code:
A1
Abstract:
A method for preparing DL-proline, comprising the following steps: mixing L-proline and glacial acetic acid, stirring and raising the temperature to 60-75°C, continuing to maintain the temperature and stir for 2-6 hours and then distilling; the distillation method comprises first distilling until there is no liquid outflow, and then continuing to distill for 20-40 minutes; concentrating the residue after distillation to obtain concentrated solution A; mixing concentrated solution A with isopropanol and stirring until crystal precipitation is complete, collecting the crystals, and rinsing with isopropanol to obtain a crude product; mixing the crude product, activated carbon, and water and stirring until the crude product is completely dissolved, filtering to remove the activated carbon, and concentrating the residue after filtering to obtain concentrated solution B; mixing concentrated solution B with isopropanol and stirring until crystal precipitation is complete, collecting the crystals, rinsing with isopropanol and, after rinsing, drying the crystals to obtain DL-proline. The present method for preparing DL-proline has a simple process, is convenient for industrial operations, and increases the product yield and quality.
Inventors:
ZHANG XIAOFENG (CN)
Application Number:
PCT/CN2020/096709
Publication Date:
December 23, 2021
Filing Date:
June 18, 2020
Export Citation:
Assignee:
SUZHOU YUANFANG CHEMICAL CO LTD (CN)
International Classes:
C07D207/16
Foreign References:
| US4401820A | 1983-08-30 | |||
| CN101863818A | 2010-10-20 | |||
| CN1569815A | 2005-01-26 | |||
| US3213106A | 1965-10-19 |
Other References:
HE QUAN, PENG YANGFENG,CAI SHUIHONG: "Racemization of Prol ine in Acetic Acid Solution", HUADONG LI-GONG DAXUE XUEBAO - JOURNAL OF EAST CHINA UNIVERSITYOF SCIENCE AND TECHNOLOGY, GAI-BAN BIANJIBU, SHANGHAI, CN, vol. 29, no. 6, 31 December 2003 (2003-12-31), CN , pages 566 - 568, XP055881264, ISSN: 1006-3080, DOI: 10.14135/j.cnki.1006-3080.2003.06.006
YAMADA S., ET AL.: "METHOD FOR THE RACEMIZATION OF OPTICALLY ACTIVE AMINO ACIDS", THE JOURNAL OF ORGANIC CHEMISTRY, AMERICAN CHEMICAL SOCIETY, vol. 48., no. 06., 25 March 1985 (1985-03-25), pages 843 - 846., XP000604702, ISSN: 0022-3263, DOI: 10.1021/jo00154a019
YAMADA S., ET AL.: "METHOD FOR THE RACEMIZATION OF OPTICALLY ACTIVE AMINO ACIDS", THE JOURNAL OF ORGANIC CHEMISTRY, AMERICAN CHEMICAL SOCIETY, vol. 48., no. 06., 25 March 1985 (1985-03-25), pages 843 - 846., XP000604702, ISSN: 0022-3263, DOI: 10.1021/jo00154a019
Attorney, Agent or Firm:
SUZHOU LUNGHENG INTELLECTUAL PROPERTY FIRM (GENERAL PARTNER) (CN)
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