Resorcinol, Nitrosation

The sulfonation-nitration strategy also provides a route to styphnic acid (5) (2,4,6-trinitroresorcinol) from resorcinol (22) but the control of temperature in this reaction is very important. The synthesis of styphnic acid (5) from the nitration of 2,4-dinitroresorcinol (24) with mixed acid or concentrated nitric acid is a higher yielding route. 2,4-Dinitroresorcinol (24) is conveniently prepared from the nitrosation of resorcinol (22) followed by oxidation of the resulting 2,4-dinitrosoresorcinol (23) with dilute nitric acid. 2,4-Dinitrosoresorcinol (23) also generates styphnic acid (5) on treatment with concentrated nitric acid. ... 

Nitrosation of phenolic substrates usually uses nitrous acid prepared in situ from a dilute mineral acid and an alkali metal nitrite. In general, for every phenolic group present in a substrate an equal number of nitroso groups can be introduced into the aromatic ring phenol, resorcinol and phloroglucinol react with nitrous acid to form 4-nitrosophenol, 2,4-dinitrosoresorcinol and 2,4,6-trinitrosophloroglucinol respectively. 

Clenbuterol in pork, beef, and hog liver Co(II) ion as 4-(2-thiazolylazo)resorcinol (TAR) or 5-methyl-4-(2-thiazolylazo)resorcinol (5MTAR) total phenols after nitrosation of USEPA classified 11 priority pollutant phenols polyprenol and doUchoP ... 

For nitrosation, a weak (2.75%) aqueous soln of I mole resorcinol is acidified with 2 moles of sulfuric acid. The soln is cooled to ca -2°, and a 10% aqueous soln of Na nitrite is added dropwise. The pptd yellowish crysts are washed with w and separated on a sintered glass filtering crucible, applying a vacuum suction. The separation may also be conducted in a centrifuge... 

K.S. Warren stated in PATR 1328(1943) that he nitrosated the purified resorcinol, mp... 

Iron, copper and nickel complexes of the products obtained by the nitrosation of arylazore-sorcinols have been claimed139 to dye leather in brown shades having excellent fastness to light. The structures of these products is open to debate since the position in which the resorcinol moiety is nitrosated (205 or 206) has not been established with any degree of certainty. Further, dyestuffs of this type, particularly those (207) derived from o-aminophenols, contain two metallizable systems and no information appears to be available regarding the stoichiometry and structure of their iron complexes. 

The nitrosation is effected in a well known way. A weak (2.75%) aqueous solution of one mole of resorcinol is acidified with 2 moles of sulphuric acid. The solution is cooled down to -2°C and a 10% aqueous solution of 2 moles of NaN02 is added, dropwise. Crystalline yellowish 2,4-dinitrosoresorcinol is precipitated in theoretical yield. The precipitate is washed and separated in a centrifuge or on a vacuum filter prior to oxidation. From dinitrosoresorcinol the divalent lead salt of dinitrosoresorcinol may be prepared, having initiating properties. 

Hydro quinone transforms in the presence of irradiated nitrite to yield ben-zoquinone and hydroxybenzoquinone [78,79]. At the irradiation wavelength adopted in the cited works (365 nm), hydroquinone direct photolysis should be limited and benzoquinone most likely forms upon reaction between hydroquinone and hydroxyl (reactions 44 and 45 hydroquinone absorbs radiation at A, < 320 nm). Hydroxybenzoquinone is likely to be a product of benzoquinone photolysis. No nitration or nitrosation intermediates of hydroquinone were observed in the presence of nitrite under irradiation, differently from the cases of resorcinol and catechol [78,79]. The reaction between hydroquinone and nitrogen dioxide is, however, quite rapid [106,115], as confirmed by the marked inhibition of phenol nitration upon nitrite photolysis by added hydroquinone [62], The point is that the reaction between hydroquinone and NO2 mainly yields benzoquinone [62], Another interesting feature in the case of hydroquinone is the formation of the fairly stable semiquinone radical anion upon reaction between benzoquinone and depro-tonated hydroquinone. The spectrum of the resulting solution shows the typical absorption bands of the semiquinone at 308, 315, 403, and 430 nm [79]. 

Summary 4,6-Dinitroresorcinol is prepared by the action of 70% nitric acid on resorcinol diacetate. Some urea is added in-order to control the nitration and ensure no by-product nitrosation takes place. After the addition of the 70% nitric acid, the intermediate produced is treated with 90% nitric acid yielding the 4,6-dinitroresorcinol as a golden yellow solid. Commercial Industrial note For related, or similar information, see Application No. 001,243, January 7,1987, by SRI International, to Robert J. Schmitt, (Mountain View, CA, David S. Ross, Palo Alto, CA, James F. Wolfe, Palo Alto, CA. Part or parts of this laboratory process may be protected by international, and/or commercial/industrial processes. Before using this process to legally manufacture the mentioned explosive, with intent to sell, consult any protected commercial or industrial processes related to, similar to, or additional to, the process discussed in this procedure. This process may be used to legally prepare the mentioned explosive for laboratory, educational, or research purposes. 

The synthesis of the 7-hydroxy-derivatives required 5-benzyloxy-2-nitro-phenol, hitherto unknown. An earlier procedure for the synthesis of the related 5-methoxy-2-nitrophenol [118] showed, that a selective direct nitration of such electronically overheated aromatics is impossible even with dilute aqueous nitric acid. In such a case, using a weaker and more selective N-electrophile like the nitrosyl cation or an equivalent for it should be helpful because a nitroso compound thus prepared can finally be oxidised to a nitro compound. However, special problems result from the insolubility of monobenzyl resorcinol in water which made a classical aqueous nitrosation procedure impossible. 

This prompted us to develop a novel regioselective nitrosation procedure for resorcinol monoethers, e.g. for monobenzyl resorcinol, as starting material (Fig. (11)). Solid sodium nitrite in anhydrous propionic acid as solvent was an effective system for the completely regioselective nitrosation of the subject compounds. High yields of pure 2-nitroso products were obtained. Attack at the 4-position becomes only competitive in the presence of water in the solvent. Absence of water was ensured by addition of one percent of propionic anhydride. The excellent regioselectivity observed is obviously related to the presence of nitrosyl... 

Fig. (11). Regioselective nitrosation of resorcinol monoethers and oxidation to nitrophenols...

Nitrosation, The reactor was filled with 2801. water and 62401. sulphuric acid, 5 Be). 11,200 kg resorcinol were introduced and 100 kg of ice. A solution of kg of sodium nitrite dissolved in 28 1. of water was added. Yellow coloured troso compound was precipitated and immediately the solution was added to... 

Two papers [87, 88) have described a novel method of making styphnic acid. Both consist of two steps (1) nitrosation of resorcinol to dinitroso derivative. (2) oxidation and nitration of the dinitroso compound fl 7)... 

Polyhydric phenols can also be doubly nitrosated. Heinrich289 obtained 4-nitrosoresorcinol as potassium salt on dropping pentyl nitrite into a cooled solution of resorcinol and potassium hydroxide in absolute alcohol, but resorcinol is easily doubly nitrosated, at the 2,4-positions, by nitrous acid in an acid solution.289 290 N.B. preparation of trinitrosophloroglucinol may lead to an explosion.291... 

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