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GB408676A - The manufacture of symmetrically substituted azobenzene compounds - Google Patents

The manufacture of symmetrically substituted azobenzene compounds

Info

Publication number
GB408676A
GB408676A GB28770/32A GB2877032A GB408676A GB 408676 A GB408676 A GB 408676A GB 28770/32 A GB28770/32 A GB 28770/32A GB 2877032 A GB2877032 A GB 2877032A GB 408676 A GB408676 A GB 408676A
Authority
GB
United Kingdom
Prior art keywords
hours
acid
mixture
sodium salt
azo
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB28770/32A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
IG Farbenindustrie AG
Original Assignee
IG Farbenindustrie AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by IG Farbenindustrie AG filed Critical IG Farbenindustrie AG
Publication of GB408676A publication Critical patent/GB408676A/en
Expired legal-status Critical Current

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09BORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
    • C09B29/00Monoazo dyes prepared by diazotising and coupling

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Investigating Or Analysing Biological Materials (AREA)

Abstract

Azo dyes and intermediates.--Symmetrically substituted azobenzene derivatives, which are dyestuffs or are intermediates for the preparation of azo dyestuffs, are obtained by reducing in an alkaline medium a 1-nitro-4-halogenbenzene-3-sulphonic or carboxylic acid to the corresponding 4 : 4<1>-dihalogenazobenzene-3 : 3<1>-disulphonic or dicarboxylic acid and replacing the halogen atoms by amino or hydroxy groups by known methods. Alternatively, the reduction may be carried further to produce the hydrazo compounds which are then oxidized to the azo compounds before replacing the halogen atoms. The following examples are specified. (1) 5-Nitro-2-chlorobenzoic acid is dissolved in caustic soda solution and zinc dust is slowly stirred in while keeping the temperature below 50 DEG C., the mixture being then heated during 2 hours to 90 DEG C. and maintained at this temperature for 8 hours; the mixture is then filtered hot and the sodium salt of 4 : 4<1>-dichloroazobenzene-3 : 3<1>-dicarboxylic acid is salted out from the filtrate and is heated under pressure for about 10 hours at 150 DEG C. with caustic soda solution containing some copper powder or a suitable copper compound; the excess of alkali is then neutralized and the sodium salt of 4 : 4<1>-dihydroxyazobenzene-3 : 3<1>-dicarboxylic acid is salted out. (2) 5-Nitro-2-chlorobenzenesulphonic acid is dissolved in aqueous ammonia, zinc dust is added while keeping the temperature below 60 DEG C. and the mixture is heated during 2 hours to 90 DEG C.; the mixture is then filtered, air is blown into the filtrate to oxidize the 4 : 4<1>-dichlorohydrazobenzene-3 : 3<1>-disulphonic acid and the sodium salt of the azo compound is salted out; this product is heated under pressure for 8 hours at 160 DEG C. with aqueous ammonia, whereupon the excess of ammonia is driven off and the sodium salt of 4 : 4<1>-diaminoazobenzene-3 : 3<1>-disulphonic acid is salted out. The Specification as open to inspection under Sect. 91 comprises also the production of similar symmetrical azo compounds in which the benzene nuclei are further substituted, e.g. by alkyl. This subject-matter does not appear in the Specification as accepted.
GB28770/32A 1931-10-17 1932-10-14 The manufacture of symmetrically substituted azobenzene compounds Expired GB408676A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE408676X 1931-10-17

Publications (1)

Publication Number Publication Date
GB408676A true GB408676A (en) 1934-04-16

Family

ID=6422324

Family Applications (1)

Application Number Title Priority Date Filing Date
GB28770/32A Expired GB408676A (en) 1931-10-17 1932-10-14 The manufacture of symmetrically substituted azobenzene compounds

Country Status (1)

Country Link
GB (1) GB408676A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0036636A1 (en) * 1980-03-26 1981-09-30 Pharmacia Ab A method and intermediates for preparing 3,3'-azo-bis-(6-hydroxy benzoic acid)
EP0036637A1 (en) * 1980-03-26 1981-09-30 Pharmacia Ab Use of 3,3'-azo-bis-(6-hydroxy benzoic acid) as a drug and pharmaceutical compositions containing the same
FR2500824A1 (en) * 1981-03-02 1982-09-03 Searle & Co 5,5'-AZOBIS-SALICYLIC ACID AND ITS USEFUL SALTS, IN PARTICULAR FOR THE TREATMENT OF INFLAMMATORY DISEASES OF THE INTESTINE
EP0066861A1 (en) * 1981-06-08 1982-12-15 Pharmacia Ab Dianionic 5,5'-azobis-salicylic-acid composition

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0036636A1 (en) * 1980-03-26 1981-09-30 Pharmacia Ab A method and intermediates for preparing 3,3'-azo-bis-(6-hydroxy benzoic acid)
EP0036637A1 (en) * 1980-03-26 1981-09-30 Pharmacia Ab Use of 3,3'-azo-bis-(6-hydroxy benzoic acid) as a drug and pharmaceutical compositions containing the same
FR2500824A1 (en) * 1981-03-02 1982-09-03 Searle & Co 5,5'-AZOBIS-SALICYLIC ACID AND ITS USEFUL SALTS, IN PARTICULAR FOR THE TREATMENT OF INFLAMMATORY DISEASES OF THE INTESTINE
JPS57144219A (en) * 1981-03-02 1982-09-06 Searle & Co Azobissalicylic acid and salts thereof and medicinal composition containing them
EP0066861A1 (en) * 1981-06-08 1982-12-15 Pharmacia Ab Dianionic 5,5'-azobis-salicylic-acid composition

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