Organic compounds -- part of the class 532-570 series – Organic compounds – Nitriles
Reexamination Certificate
2005-04-07
2010-06-08
Shiao, Rei-tsang (Department: 1628)
Organic compounds -- part of the class 532-570 series
Organic compounds
Nitriles
Reexamination Certificate
active
07732631
ABSTRACT:
An improved process for the preparation of 2-chlorobenzylidenemalononitrile (CS) comprising of the steps of: preparing malononitrile suspension by adding 5-20% (wt %) preferably 12-14% malononitrile to water while constantly stirring and then adding 0.05-0.5% (v/v) preferably 0.1-0% of a catalyst like piperidine, pyridine, 2-picoline, 3-picoline, 4-picoline or morpholine preferably piperidine piperidine with constant stirring at 20-30° C.; condensing the malononitrile suspension prepared in step (a) with 2-chlorobenzaldehyde by adding 10-15% (w/v) preferably 25-30%, of 2-chlorobenzaldehyde cover a period at 30-45 minutes so that the temperature of the reaction mixture remains below 50° C., constantly stirring for 20-40 minutes, then filtering the CS and drying it at 20-30° C. under water vacuum for 3-5 hrs.
REFERENCES:
patent: 3715379 (1973-02-01), Berry et al.
patent: 3963770 (1976-06-01), Knapp
Shi, Da Quing et al., “The condensation of aromatic aldehydes with acidic methylene compounds in water”; Chinese Chemical Letters 2003, 14(12); pp. 1242-1243; ISSN 1001-8417.
Zhang, Shu et al., “Condensation of aromatic aldehydes with active methylene compounds in water”; Zuzhou Shifan Daxue Xuebao, Ziran Kexueban 2003; 21(2); pp. 42-45; ISSN 1007-6573.
Wang S., et al., The Knoevenagel condensation of aromatic aldehydes with malononitrile or ethyl cyanoacetate in the presence of CTMAB in water; Synthetic Communications 2001 31(5); pp. 673-677; ISSN 0039-7911.
Dubey Vinita
Ganesan Kumaran
Malhotra Ramesh Chandra
Pande Ambuja
Sekhar Krishnamurthy
Director General, Defence Research & Development Organisati
Shiao Rei-tsang
The Webb Law Firm
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