Лако-красочные материалы — производство

Tetramethyldiaminodiphenylmethane is oxidized in dilute acid solution with just the calculated amount of lead dioxide in paste form. Lead dioxide, once dried, cannot be used for such oxidations because it is not in a fine enough state of subdivision. The oxidizing strength of lead dioxide paste must be determined by titration (see Analytical Section). However, […]

This azo dye component is obtained from p-nitroacetanilide by neu­tral reduction, using a procedure almost exactly like several that have already been described. In an iron beaker equipped with a stirrer (Fig. 17), a mixture of 250 grams of pulverized cast iron shavings, 15 cc. 40 per cent acetic acid, and 500 cc. water, is […]

Just as* with aniline, many other aromatic amines (e. g., toluidine, xylidine, chloroaniline, a-naphthylamine, benzidine, aminoanthraqumone, and others) are converted into sulfonic acids by the so-called baking process as described above.[25] In contrast to the usual sulfonation procedures which use an excess of sulfuric acid or oleum, this process uses only the theoretical quantity of […]

15.6 grams (0.1 mole) of m-chlorodimethylaniline* is dissolved in 40 cc. concentrated hydrochloric acid, and after cooling, 7.7 cc. 39 per cent formaldehyde is added. This mixture is poured into the well stirred solu­tion of 0.125 mole of p-tolylhydroxylaminesulfonic acid, i. e., 225 cc. of the solution prepared above. Then, 70 cc. of a 20 […]

The common reduction methods, using iron in acid or almost neutral solution, are not usable for selectively reducing one of several nitro groups present in a molecule. This is true also for those cases where some other easily reducible group, such as the azo group, is present along with the nitro group (see page 289). […]

Since p-chloro-o-nitrophenol is easily volatile with steam, the reaction vessel must be provided with a tight cover and a reflux condenser (cf. Fig. 11). It is recommended that a very weak vacuum be applied to the end of the reflux condenser so that vapor does not escape from the opening when additions are made, but […]

The reduction is carried out in the manner described for the prepara­tion of aniline (page 75). The moist filter cake of nitrobenzene-2,5- disulfonic acid, obtained above, is added in small portions over the course of about 1 hour to a boiling, well stirred mixture of 200 grams of iron powder, 1 liter of water, and […]

The moist filter cake of sodium 2-nitrochlorobenzene-4-sulfonate (page 106) is dissolved in 400 cc. boiling water; the solution is filtered to remove any undissolved residue. To the filtrate is added 300 grams of crystalline neutral sodium sulfite (Na2S03 * 7H20), taking care that the resulting solution is not alkaline to phenolphthalein. (If it is, hydrochlo­ric […]

Cl Cl NH, A SO, H / with MgO (or СаСОз) in boil­ 1 —> + 1 1 ing aqueous solution (wooden V 4/ / vat) NO, NO, NH, NH,   NH, /   tU Bechamp reduction   Easily solublesodium salt   Main reaction   NH   NH   SO, H   NO,   NH, […]