Лако-красочные материалы — производство

A solution of 0.01 mole of the acid in the required amount of soda solution is diluted to about 250 cc., acidified with 25 cc. concentrated hydrochloric acid, and titrated with 1 N nitrite solution. The per cent purity is given by no. of cc. x 10. The endpoint must be determined by spotting the […]

a-Naphthol couples much more easily than /З-naphthol and would give too high values in alkaline solution. Hence, the coupling is carried out in acetic acid solution in the following manner: The a-naphthol is dissolved as described for /З-naphthol, and the solution is diluted and then precipitated with dilute acetic acid in the presence of 25 […]

A solution of 0.01 mole (1.44 grams) of /f-naphthol in 2 cc. 30 per cent sodium hydroxide is diluted to 400 cc., and 25 cc. 10 per cent soda ash is added. Ice-cold 0.1 N phenyldiazonium solution is added from a graduated cylinder or a cooled burette until a drop of the re- action mixture […]

Many amines cannot be analyzed directly by diazotization, either because they form diazoamino compounds or because they give diazo­nium compounds which color starch-iodide paper just as free nitrous acid does. These amines, exemplified by the nitroanilines, dichloro — anilines, etc. must be determined indirectly. The amine (0.01 mole, for example) is dissolved in concentrated or […]

The amine is titrated with hydrochloric acid and sodium nitrite in very dilute solution, and the resulting diazonium salt is coupled with an accurately known amount of a phenol, usually Schaeffer salt. With other compounds, such as H acid, amino R acid, etc., one sample is diazotized and another is coupled with diazotized aniline or […]

50 cc. of the aniline solution is measured out and mixed with 50 cc. concentrated hydrochloric acid. The mixture is cooled by placing the measuring flask in ice water, and 50 cc. 1 N nitrite solution is added while the mixture is swirled to provide agitation. The solution is kept in ice water for 20 […]

A solution of 75 grams of technical sodium nitrite in a small volume of water is filtered and made up to 1 liter at 17.5°C. This solution is used to titrate 50 cc. 1N sulfanilic acid solution, as follows: The sulfanilic acid solution is pipetted into a 500-cc. beaker, diluted with 200 cc. ice water, […]

A strongly alkaline solution of 250 grams of technical sulfanilic acid in about 1 liter soda solution is boiled until all of the aniline has been driven off. The solution is then filtered and made strongly acid with hydrochloric acid. The precipitated material is filtered off after 12 hours, washed with a small amount of […]

The determination of sodium nitrite is done by the well known oxidation method with potassium permanganate. This procedure, how­ever, always gives too high values for the plant chemist since the per­manganate oxidizes any other oxidizable material which may be present in the nitrite. Despite this disadvantage, the method is used in nitrite plants. Only one […]

Accurate analytical determination of starting materials is essential in the dye industry. The methods which are used are partly physical, partly chemical. With many products, only physical data, such as melt­ing point, freezing point, and boiling poiqt, are determined. Thus, aniline, toluidine, nitro compounds, and many others, are characterized solely by these measurements. In some […]