Zhejiang Heben Pesticide & Chemicals Co., Ltd. (Zhejiang Heben), one of the leading fungicide manufacturers in China, has successfully completed the innovation on synthetic process of difenoconazole, and this project has been checked and accepted by the Science Technology Department of Zhejiang Province smoothly, according to CCM’s November Issue of Fungicides China News.
Difenoconazole, a triazole fungicide with high efficiency, low toxicity and broad spectrum, is widely applied to prevent and control various diseases, such as sheath blight, rust, early blight, powdery mildew, leaf spot, scab, etc., in the fields of wheat, rice, tomato, pepper, grape, citrus and so forth.
It is well known that Syngenta is the first company developing difenoconazole which is conventionally prepared from 2,4-Dichloroacetophenone followed by etherification, bromination, ketal reaction and nucleophilic substitution, with an overall yield of about 70%.
However, Zhejiang Heben's new process of synthesizing difenoconazole is relatively more advantageous than the conventional method mentioned above. In detail, beginning with 3，4' -dichlorodiphenylether, difenoconazole is synthesized by acylation, condensation and cyclization, with a total yield of about 81%. What's more, the purity of difenoconazole can reach over 97%.
Besides high yield and purity, this new method still has other advantages, such as easy operation, short reaction time, little "three wastes", etc., to improve the synthetic process of difenoconazole, according to Zhejiang Heben. The specific synthesis route of difenoconazole is as follows.
As description in the article on the study of new synthetic process of difenoconazole, the result shows that isobutyl alcohol, a low-boiling solvent, is substituted for a high-boiling one--dimethylamide (DMF) in the condensation reaction and the former is easily recovered compared with the latter.
In cyclization reaction, replacing p-toluenesulfonic acid with the homemade composite catalyst can not only shorten the reaction time but also reduce the consumption of 1,2-Propanediol to a great extent; the yield of difenoconazole is risen by 5% accordingly when using homemade composite catalyst of Zhejiang Heben.
Last but not least, adopting composite solvent crystallization technique achieves the breakthrough in crystallization problem in the purification process of difenoconazole, which can also greatly increase product content.
Zhejiang Heben constructed a 100t/a difenoconazole technical production line as early as 2007, thereafter the company has gradually expanded its capacity to the current about 450t/a, says Mr. Li, Sales Manager of Zhejiang Heben. Moreover, most difenoconazole technical of Zhejiang Heben is exported to the overseas market.
Source: Fungicides China News 1111
http://www.cnchemicals.com/Newsletter/NewsletterDetail.aspx?id=2
Main content of Fungicides China News 1111:
Shandong Dacheng continues financial deficit in Q3 2011
Lier Chemical: Revenue jumps but net profit drops from Jan. to Sept. 2011
Yangnong Chemical surges in Q3 net profit
Jiangsu Huifeng to establish subsidiary in Lianyungang of Jiangsu
Shenyang Sciencreat successfully registers pyrametostrobin
New blood brings more vitality to Wuhan Kernel
Zhengye Zhongnong improving fungicide development
Jiangsu Sword wins a national invention patent recently
Zhejiang Heben innovates synthetic process of difenoconazole
Ex-factory price of mancozeb 90% TC sharply declines in early Nov. 2011
Ningnanmycin promotes well especially in tobacco virus disease control market
Pesticide output up 15.7% year on year in the first three quarters of 2011
Supply of 1,2,4-triazole under tight recently
Autumn-winter sowing completes 65% by late Oct. 2011
Domestic chemical pesticide application to continue decreasing in 2012
Fungicides China News, a monthly publication issued by CCM International on 10th of every month, provides a wealth of exclusive information and analysis, research and development dynamics of domestic competitors, analysis on import and export of key products, cooperative opportunities with domestic and foreign companies, and market information of foreign patent-expired products.
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