Bisulfite nitrous acid

Base deamination is accelerated by nitrous acid and sodium bisulfite. Nitrous acid nonspecifically promotes base deamination in both double-stranded and single-stranded DNA. In contrast, sodium bisulfite specifically promotes cytosine deamination in single-stranded DNA. Some single-stranded regions do exist in cellular DNA, at least temporarily—for example, during transcription. In some cases, sodium bisulfite is used as a food additive. It is also used in the wine industry. 

A convenient laboratory route involves the reduction of an aqueous solution of nitrous acid or potassium nitrite with bisulfite under carefully... 

Mendiara, S. N., E. Ghibaudi, L. J. Perissinotti, and A. J. Colussi, Free Radicals and Diradicals in the Reaction between Nitrous Acid and Bisulfite in Acid Aqueous Media, . /. Phys. Chem., 96, 8089-8091 (1992). 

Nitrous acid, formed from organic precursors such as nitrosamines and from nitrite and nitrate salts, is a potent accelerator of the deamination of bases. Bisulfite has similar effects. Both agents are used as preservatives in processed foods to prevent the growth of toxic bacteria. They do not appear to increase cancer risks... 

Phenylglyoxal has been prepared from isonitrosoacetophenone through the bisulfite compound 2,3 or by treatment with nitro-sylsulfuric acid 4 or with nitrous acid.3 It also has been prepared by the oxidation of benzoylcarbinol with copper acetate,6 by heating bromophenacyl acetate,7 and by the oxidation of acetophenone with selenium dioxide.1... 

The nitrated tropaeolines split off nitrous acid when dissolved in hot water and this acid attacks the copper equipment used by the dyers. There is a demand, therefore, for a nitrous acid-free azo yellow which is prepared in the following way. The freshly filtered azo yellow is heated to 90°C. with 4 parts of water, splitting off most of the nitrous and nitric acids. After about 3 hours, 5 per cent sodium bisulfite solution is added to remove the last traces of nitric acid. The mass gives off red fumes and foams strongly, so the process must be done in large vats. This treatment always results in a loss of 15 to 20 per cent of the dye. (See also azo fiavine FF, page 272). 

SYNS CHAMBER CRYSTALS NITRO ACID SULFITE NITROSONIUM BISULFITE NITROSYL HYDROGEN SULFATE NITROSYL SULFATE SULFURIC ACID, MONOANHYDRIDE with NITROUS ACID... 

Properties Pinkish-white to gray needles. Soluble in hot water but almost insoluble in cold water. Derivation (3-naphthol is nitrated to mtroso-ji-naphthol by reaction with nitrous acid and the product treated with sodium bisulfite. Upon acidification the free sulfurous acid effects simultaneous reduction and sulfonation. 

Formation of Hydroxylamine Disulfonate by Reaction of Nitrous Acid with Bisulfite Ion. Hydroxylamine disulfonate (HADS) is formed according to the following net reaction ... 

Hydroxylamine salts are made commercially in two ways the hydrolysis of primary nitroparaffins and the cathodic reduction of nitric acid. In the laboratory it is easiest to reduce nitrous acid with a bisulfite and then hydrolyze the resulting salt of hydroxylamine disulfonic acid. The reactions are as follows ... 

Sulfur dioxide or bisulfites are rarely used in combination with nitrites, because their reactions in acidic media yield sulfonates of either hydroxylamine or ammonia, which destroys the preservative activity of the individual additives. The reaction of alkali metal nitrites with bisulfite at lower temperatures leads to the formation of hydroxylamine N, JV-disulfonate, H0N(S03)2, which is hydrolysed to hydroxylamine JV-sulfonate, HONHSOj and further to hydroxylamine (H2NOH). At elevated temperatures complete substitution proceeds with the formation of ammonia JV-trisulfonate, N(S03)j , which is hydrolysed to sulfa-mate, H2NSOj . Subsequent reaction of sulfamate with nitrous acid leads to production of bisulfate ion and nitrogen gas ... 

FIGURE 1.8 Some chemical reactions of bases and nucleotides, (a) Hydrolysis of a dinucleotide by alkali. Bases are denoted by B1 and B2. R denotes ribose or deoxyribose. (b to k) Chemical reactions (b) bisulfite, (c) chloroacetaldehyde, (d) diethyl pyrocarbonate, (e) dimethyl sulfate, (f) formaldehyde, (g) glyoxal, (h) hydrazine, (i) nitric acid, (j) nitrous acid, and (k) osmium tetroxide. Partly from R. L. P. Adams, J. P. Knowler, and D. P. Leader (1986). In The Biochemistry of the Nucleic Acids, 10th ed., pp. 5—34. Chapman Hall, with permission. 

Nitrous and nitric acids are produced in the aqueous phase after NO2 and/or N2O3 are absorbed into solution and sulfur oxyacids, such as sulfite/bisulfite or pyrosulfite, are formed if SO2 dissolves in the solution. Interaction among oxides of nitrogen, nitrogen oxyacids, sulfur oxyacids, oxygen, and trace metal ions such as Fe(III) or Mn(II) can take place in a flue gas wet scrubber. Identifying all reactions involved in this complex system is impossible. However, important reactions must be identified and characterized in order to improve the performance of a scrubber. 

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