Iron filings

The azoxybenzene in turn, when heated with iron filings, readily undergoes C4HjNO NC,Hs + Fe = C.HjNtNC.Hs + FeO further reduction to azobenzene. 

Other halogen carriers may be used, e.g., 1-2 g. of iron filings, or 1 g. of aluminium amalgam. The bromine must then be added slowly from a dropping funnel to the benzene warmed on a water bath the apparatu.s shown in Fig. II, 13, 9 is suitable and a trap for the hydrogen bromide must, however, be inserted into the top of the condenser. After all the bromine has been introduced, the mixture is heated on a water bath until no red vapours are visible above the liquid. The Subsequent procedure is as above. 

Method B. Reduction with iron and hydrochloric acid. Place 40 ml. of water and 30 g. of grease-free iron filings (1) in a 750 or 1,000-ml. round-bottomed flask, and 25 g. (21 ml.) of nitrobenzene in a small beaker or conical flask. W arm the former on a water bnth at about 60°. Add... 

Commercial Iron Olings, grease free are quite satisfactory. If fine iron filings are used, they should be washed with ether and dried in the air. 

Place 84 g. of iron filings and 340 ml. of water in a 1 - 5 or 2-litre bolt-head flask equipped with a mechanical stirrer. Heat the mixture to boiling, stir mechanically, and add the sodium m-nitrobenzenesulphonate in small portions during 1 hour. After each addition the mixture foams extensively a wet cloth should be applied to the neck of the flask if the mixture tends to froth over the sides. Replace from time to time the water which has evaporated so that the volume is approximately constant. When all the sodium salt has been introduced, boU the mixture for 20 minutes. Place a small drop of the suspension upon filter paper and observe the colour of the spot it should be a pale brown but not deep brown or deep yellow. If it is not appreciably coloured, add anhydrous sodium carbonate cautiously, stirring the mixture, until red litmus paper is turned blue and a test drop upon filter paper is not blackened by sodium sulphide solution. Filter at the pump and wash well with hot water. Concentrate the filtrate to about 200 ml., acidify with concentrated hydrochloric acid to Congo red, and allow to cool. Filter off the metanilic acid and dry upon filter paper. A further small quantity may be obtained by concentrating the mother liquid. The yield is 55 g. 

Iron exchange Iron filings Iron gelbs Iron-graphite Iron hureaulite Iron hydroxide Iron(II)... 

Iron Reduction. The reduction of nitrophenols with iron filings or turnings takes place in weakly acidic solution or suspension (30). The aminophenol formed is converted to the water soluble sodium aminopheno1 ate by adding sodium hydroxide before the iron-iron oxide sludge is separated from the reaction mixture (31). Adjustment of the solution pH leads to the precipitation of aminophenols, a procedure performed in the absence of air because the salts are very susceptible to oxidation in aqueous solution. 

Wire sparklers are wires coated with pyrotechnic composition which are hand-held and produce a gende spray of gold sparks from iron filings. Fountains are cardboard tubes filled with chemical mixtures that produce a spray of color and sparks extending 2—5 m into the air. Roman candles are cylindrical tubes which repeatedly fire colored stars distances of 5—20 m into the air. These items typically contain 5—12 stars. 

One of the first practical methods for the manufacture of cinnamyl alcohol involved reduction of cinnamic aldehyde diacetate with iron filings in acetic acid. This approach suffered from low yields and Hberation of a significant amount of the starting aldehyde. 

Phthalocyanines. Phthalocyanine is the only novel chromogen of commercial importance discovered siace the nineteenth century. It was discovered accidendy ia 1928, when duriag the routine manufacture of phthalimide from phthaUc anhydride and ammonia it was found that the product contained a blue contaminant. Chemists of Scottish Dyes Ltd, now part of Zeneca, carried out an iadependent synthesis of the blue material by passiag ammonia gas iato molten phthaUc anhydride containing iron filings. The importance of the colorant was realized (it was iatensely colored and very stable), and a patent appHcation was filed ia the same year. 

In a 12-1. flask fitted with a mechanical stirrer and a short reflux condenser are placed 1800 g. (32.2 moles) of iron filings (Note i), 3 1. (52.5 moles) of glacial acetic acid, 3 1. of water, and 450 g. (3.95 moles) of heptaldehyde (Note 2). The mixture is heated on the steam bath, with stirring, for six to seven hours (Note 3). The flask is then fitted to an apparatus for steam distillation (Org. Syn. 2, 80) and the mixture distilled in a current of steam (Note 4) until no more oil passes over (7-8 1. of distillate). The oil is then separated, and the aqueous part distilled to recover a small quantity of dissolved or suspended heptyl alcohol. 

The Iron filings used were free of grease and ore. Ninety-five per cent of the filings passed an 8o-mesh screen and 6o per cent passed a loo-mesh screen. Grade D iron supplied by the Master Builders Company, Cleveland, Ohio, is ready for use and very satisfactory. 

It has been frequently noted that certain lots of iron filings are not satisfactory for the reduction of heptaldehyde to heptyl alcohol in acetic acid solution. E. E. Reld and J. R. Ruhoff have found that the addition of a solution of 20 g. of nickel cliloride hexahydrate in 50 cc. of water immediately after the addition of the aldehyde will cause the reaction to start at once and wiU greatly accelerate the rate of reaction so that it is complete in two hours instead of the usual six to seven hours. The checkers have found this to be the case even with a lot of iron which could not be made to react when reduced in hydrogen. It is also recommended that the reaction mixture be divided between two 12-I. flasks and that 3 1. of water be added to each half immediately at the end of the reaction. This prevents the mixture from setting to a hard mass in case the steam distillation is not carried out at once, and also reduces the amount of foaming. 

The quality of the iron used in preparing the ferrous chloride has a marked effect on the yield of ferrocene. The checkers employed Rascher and Betzold (730 N. Franklin, Chicago, 111.) 300-mesh iron powder, reduced by hydrogen. When 40-mesh iron filings were used, the yield of ferrocene was much lower (ca. 33%). 

Gattefoss6 and Morel La Parfumerie Moderne, 1919, 114) describe a method for the production of vanillin by reducing nitrobenzene-sul-phonic acid with iron filings and hydrochloric acid in the presence of guaiacol and formic aldehyde. The first-named body is reduced to phenyl-hydroxylamine-sulphonic acid, which reacts with the guaiacol as follows —... 

Eisen-feilicht, n., -feile, /. -feilspaUe, m.pl. iron filings, -feilstaub, m. fine iron filings, -feinschlacke, /. iron refinery slag, -firms, m. varnish for iron, -fiasche, /. iron cylinder (for gases), -fieck, m. iron spot, iron stain. 

Mix together 4.4 grams of ammonium chloride, 18 ml of methanol, 9 ml of water and 3.0 grams of 2-sulfamyl-4-chloro-nitrobenzene. Heat the mixture to reflux. Add portionwise 4.4 grams of iron filings during a period of about VA hours. Cool the mixture and filter. Concentrate the filtrate to a residue. Triturate the residue with 15 ml of water and filter the solid. Recrystallize the solid from aqueous methanol to yield substantially pure 2-sul-famyl-4-chloroaniline. 

Iron filings left in the bottom of the tank dr deposits of inert material are liable to interterejwith the forrriatjon.of the protective scale by the. water and can lead to. f ailure. ... 

These are stringent requirements yet a veiy common material does this job spectacularly well iron filings. Metallic iron contains neutral iron atoms that readily donate electrons to become Fe or Fe cations, neither of which is significantly toxic. Fe Fe + 2 e" Thus, when iron reacts with trichloroethylene or chromate, all the products are relatively non toxic. 

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