Title:
METHOD FOR PURIFYING 4-CYANOPYRIDINE BY MEANS OF MELTING AND CRYSTALLIZING
Document Type and Number:
WIPO Patent Application WO/2021/017649
Kind Code:
A1
Abstract:
Disclosed is a method for purifying 4-cyanopyridine by means of melting and crystallizing, comprising the following steps: (1) Melting 4-cyanopyridine: adding crystals of 4-cyanopyridine into a reactor under normal pressure and melting the crystals of 4-cyanopyridine at a reactor temperature controlled to be 80-90°C; (2) Temperature reduction: reducing the temperature of molten 4-cyanopyridine to 71.5-73.5°C at a certain temperature reduction rate by performing temperature control on the reactor; (3) Crystallization: enabling crystallization at a maintained temperature of 71.5-73.5°C; and (4) Separation and extraction: discharging the base solution from the resulting crystals, increasing the reactor temperature to 80-90°C again, and melting the resulting crystals to obtain a finished 4-cyanopyridine product. The method for purifying 4-cyanopyridine by means of melting and crystallizing according to the present invention has a simple process, and can increase the overall productivity and purity of the finished product, without any resulting by-products and contaminants, by means of controlling the rate of temperature reduction during temperature-reduction crystallization to avoid a peritectic phenomenon.
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Inventors:
QIAN QIAN (CN)
YANG JINGCHENG (CN)
XU LEI (CN)
CAO ZHAOBING (CN)
MA XINGFU (CN)
YANG JINGCHENG (CN)
XU LEI (CN)
CAO ZHAOBING (CN)
MA XINGFU (CN)
Application Number:
PCT/CN2020/095081
Publication Date:
February 04, 2021
Filing Date:
June 09, 2020
Export Citation:
Assignee:
ANHUI REDPONT BIOTECHNOLOGY CO LTD (CN)
International Classes:
C07D213/84
Foreign References:
| CN106478498A | 2017-03-08 | |||
| CN101602719A | 2009-12-16 | |||
| GB815278A | 1959-06-24 | |||
| CN110272382A | 2019-09-24 | |||
| CN110790702A | 2020-02-14 |
Other References:
DUAN XIAOGANG; ZHANG FUCHENG: "Study on the catalyst for the synthesis of 4-cyanopyridine by ammoxidation", SCIENCE & TECHNOLOGY INFORMATION, vol. 36, 31 December 2013 (2013-12-31), pages 67, XP009525762, DOI: 10.16661/j.cnki.1672-3791.2013.36.042
OKAMOTO, TOSHIHIKO; HIROBE, MASAAKI; MIZUSHIMA, CHIEKO; OHSAWA, AKIO: "Reaction of N-Aminopyridinium Deribatives.The Reactions of 1-(N-Acylalkylamino)pyridinium Salt Derivatives with Cyanide Ion.", CHEMICAL AND PHARMACEUTICAL BULLETIN, vol. 11, no. 6, 11 June 1963 (1963-06-11), pages 780 - 785, XP009525739, DOI: 10.1248/cpb.11.780
OKAMOTO, TOSHIHIKO; HIROBE, MASAAKI; MIZUSHIMA, CHIEKO; OHSAWA, AKIO: "Reaction of N-Aminopyridinium Deribatives.The Reactions of 1-(N-Acylalkylamino)pyridinium Salt Derivatives with Cyanide Ion.", CHEMICAL AND PHARMACEUTICAL BULLETIN, vol. 11, no. 6, 11 June 1963 (1963-06-11), pages 780 - 785, XP009525739, DOI: 10.1248/cpb.11.780
Attorney, Agent or Firm:
NANJING ZHONGLIAN PATENT AGENCY CO., LTD. (CN)
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