Nitro anthraquinones

Anthraquinone on nitration at about 50°C gives mainly 1-nitro-anthraquinone. At 80 to 95°C, dinitration occurs to give a mixture of 1,5- and 1,8- isomers. These isomers are important as starting materials for the preparation of other intermediates. 

Azidoanthraquinone Fuming HNO3 2-Azido-l-nitro- anthraquinone 27... 

Other processes have been proposed for the manufacture of alizarin, for instance by melting dichloranthraquinone or nitro-anthraquinone [16] with caustic potash, but these processes have never attained commercial importance. 

Methyi-1-nitro-9,10-anthracenedione. See 2-Methyi-1 -nitroanthraquinone 2-Methyi-1-nitroanthraquinone CAS 129-15-7 EINECS/ELINCS 204-932-0 Synonyms 9,10-Anthracenedione, 2-methyi-l-nitro- Anthraquinone, 2-methyi-l-nitro- 2-Methyi-1-nitro-9,10-anthracenedione 1-Nitro-2-methyianthraquinone Empirical C15H9NO4... 

C. A typical aromatic amine. Best prepared by the prolonged action of concentrated ammonia solution at a high temperature upon anthraquinone-l-sulphonic acid in the presence of BaClj and by reduction of the corresponding nitro compound or by amination of the chloroanthraquinone. 

Anthraquinone can be brominated, chlorinated directly to the tetrachloro (I, 4, 5, 8-) stage, nitrated easily in the 1-position, but gives the 1,5-and 1,8-dinitro-derivalives on prolonged nitration the nitro groups in these compounds are easily displaced by neutral solutions of alkali sulphites yielding the corresponding sulphonic acids. Sulphonation with 20-30 % oleum gives the 2- 2,6- and 2,7-derivatives in the presence of Hg the 1- 1,5- and 1,8- derivatives are formed. 

In the anthraquinone series, apart from the special case of the amination of leucoquinizarin, sulfonic acid and nitro are the preferred leaving groups. 1-Aminoanthraquinone is manufactured from anthraquinone-l-sulfonic acid or 1-nitroanthraquinone, and 2-amino anthraquinone (betamine) from anthraquinone-2-sulfonic acid. 

Two large studies were done (250,251) for the selection of a2o, nitro, and anthraquinone dyes for carcinogen bioassay. Based on previous information or testing, a total of 30 dyes were selected based on chemical stmcture, potential exposure, and suspicion of carcinogenicity. 

Nitroalizarin (l,2-dihydroxy-3-nitro-9,10-anthraquinone. Alizarin Orange) [568-93-4] M 285.2, m 244" (dec), pKEst(i) 4.6, pKEst(2) 9.6. Crystd from acetic acid. 

The valence-bond approach may be used to provide a qualitative account of the /lmax values, and hence the hues, of many dyes, particularly those of the donor acceptor chromogen type. The use of this approach to rationalise differences in colour is illustrated in this section with reference to a series of dyes which may be envisaged as being derived from azobenzene, although in principle the method may be used to account for the colours of a much wider range of chemical classes of dye, including anthraquinones (see Chapter 4), polymethines and nitro dyes. 

The photochemistry of unsaturated nitro compounds has been investigated by Chapman and co-workers.<63) Photolysis of 9-nitro-anthracene in degassed solutions leads to anthraquinone and 10,10 -bianthrone ... 

The nitro compound is isomerized to the nitrite, which can decompose either photochemically or thermally to the 9-anthroxyl radical. This radical can then dimerize or add nitric oxide to the 10 position to form the nitrosoketone. Isomerization of the nitrosoketone yields the monooxime, which then yields anthraquinone photochemically in the presence of NO. 

Functional chemicals, 20 712 Functional dyes, anthraquinone, 9 338-341 Functional failures, 15 476 Functional fluids, alkanolamines from nitro alcohols, 2 119... 

A striking feature of disperse dye development in recent decades has been the steady growth in bathochromic azo blue dyes to replace the tinctorially weaker and more costly anthraquinone blues. One approach is represented by heavily nuclei-substituted derivatives of N,N-disubstituted 4-aminoazobenzenes, in which electron donor groups (e.g. 2-acylamino-5-alkoxy) are introduced into the aniline coupler residue and acceptor groups (acetyl, cyano or nitro) into the 2,4,6-positions of the diazo component. A PPP-MO study of the mobility of substituent configurations in such systems demonstrated that coplanarity of the two aryl rings could only be maintained if at least one of the 2,6-substituents was cyano. Thus much commercial research effort was directed towards these more bathochromic o-cyano-substituted dyes. 

Only a limited range of nitro, azo and anthraquinone disperse dyes exhibit adequate fastness to dry heat, light and weathering for application on polyester automotive fabrics. The structure of Cl Disperse Yellow 86 was modified to incorporate UV absorbers of the benzophenone, benzotriazole or oxalanilide types into the dye molecule. The derived dyes showed better fastness properties than the parent unsubstituted dye. Positioning of the photostabilising moiety within the dye molecule had little influence on the light fastness obtained, however. Built-in benzophenone residues were more effective than the other two types [177]. Nevertheless, several further monoazo and nitrodiphenylamine disperse dye... 

In an interesting study, phthalocyanine complexes containing four anthraquinone nuclei (5.34) were synthesised and evaluated as potential vat dyes and pigments [18]. Anthraquinone-1,2-dicarbonitrile or the corresponding dicarboxylic anhydride was reacted with a transition-metal salt, namely vanadium, chromium, iron, cobalt, nickel, copper, tin, platinum or lead (Scheme 5.6). Substituted analogues were also prepared from amino, chloro or nitro derivatives of anthraquinone-l,2-dicarboxylic anhydride. 

Anthraquinone-1-sulphonic acid is the traditional precursor of 1-aminoanthraquinone (6.8), the most important anthraquinone intermediate. Since it is expensive to eliminate mercury(II) ions from waste water, an alternative route via 1-nitroanthraquinone has been investigated. Nitration of anthraquinone gives, as well as the desired 1-nitro derivative, significant amounts of the 2-isomer together with 1,5- and 1,8-dinitroanthraquinones. Nevertheless, chemists at Sumitomo in Japan have optimised the nitration procedure with respect to both yield and purity of the 1-nitro compound. In particular, nitration is stopped when 80% of the anthraquinone has been substituted [5]. Nitration of anthraquinone derivatives is also of some significance. 

Nitro 2 azido-anthraquinone, Pale yel-grn crysts(from pyridine), mp 210° (dec), changing on exposure to light and in the air to pale orange-red (Ref 3). Prepd by rubbing /3-anthraquinone-azide with coned nitric acid... 

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