Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Patent
1998-11-03
1999-12-28
Siegel, Alan
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
562859, 570143, 570144, 570146, C07C 5158, C07C 5116, C07C 2513
Patent
active
060084073
ABSTRACT:
The present invention provides a method of preparing ortho-difluorobenzene derivatives, which comprises (a) providing a mixture of cyclohexenes by reacting chlorotrifluoroethylene (CTFE) and 1.3-diene in a flow reactor and distilling the resultant, and (b) dehydrohalogenating the mixture of cyclohexenes with a phase transition catalyst in :he presence of alkali metal hydroxide at temperature range of 40 to 150.degree. C. without using any organic solvent. The distillate having low boiling point, which is obtained during distillation of the resultant, is recycled into the flow reactor. The present invention also provides a method of preparing 2-chloro-4,5-difluorobenzoic acid, which comprises (a) providing a mixture of 4-chloro-1-methyl-4,5,5-trifluorocyclohexene and 5-chloro-1-methyl-4,4,5-trifluorocyclohexene by reacting chlorotrifluoroethylene (CTFE) and isoprene and distilling the resultant. (b) dehydrohalogenating said mixture in the presence of alkali metal hydroxide and a phase transition catalyst to form 3,4-difluorotoluene, to reacting said 3,4-difluorotoluene with chlorine gas without using any organic solvent to form 2-chloro-4,5-difluorotoluene, (d) photo-reacting said 2-chloro-4,5-difluorotoluene with chlorine gas under a lighting mercury lamp without using any organic solvent to form 2-chloro-4,5-difluorobenzotrichloride, and (e) reacting said 2-chloro-4,5-difluorobenzotrichloride with aqueous acid solution without using any organic solvent. The present invention also provides a method of preparing 2-chloro-4,5-difluorobenzoyl chloride by reacting the 2-chloro-4,5-difluorobenzotrichloride of step (e) above with zinc oxide.
REFERENCES:
patent: 3499942 (1970-03-01), Nefedov et al.
patent: 4374266 (1983-02-01), Fifolt et al.
patent: 4754084 (1988-06-01), Weigert
patent: 4968830 (1990-11-01), Tang
patent: 5003103 (1991-03-01), Fertel et al.
Kim Min Hwan
Lee Ho Seong
Lipkind Mariya Borisovna
Nefedov Oleg Matveyevich
Park Young Jun
Samsung General Chemicals Co. Ltd.
Siegel Alan
Zelinsky Institute of Organic Chemistry
LandOfFree
Method of preparing fluoroaromatic compounds does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of preparing fluoroaromatic compounds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of preparing fluoroaromatic compounds will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2383487