Alcohol fumes

Slides with only a thin film can be fixed by being immersed in absolute methyl or ethyl alcohol for 1 min and allowed to air dry. If the thick film is on one end of the slide and the thin film is on the other end, the thin film is fixed by a brief flooding or by immersion in alcohol and allowed to air dry, while the thick film is protected from alcohol or alcohol fumes. In a well-ventilated area, the slide may be dried vertically with the thick film up or horizontally after the thick film is covered with a dry paper towel. 

The foreman failed to appreciate the frail nature of these standard low-pressure tanks. Many low-pressure tanks are designed for positive pressures of just 8 or 10 inches of water (2 to 2.5 kPa gauge) and just 3 or 4 inches of water (3/4 to 1 kPa) vacuum. Using a hose to modify the system addressed the immediate problem of dissolving any alcohol fumes, but the presence of the hose routed to a drum containing water created a situation in which the tank could be damaged by positive pressures and vacuum conditions well beyond its design specifications. 

Properties Clear crystals or amber liquid. Mp 22C, bp 262-263C. Soluble in acetone and benzene decomposed by water or alcohol. Fumes in moist air. 

Place still warm ashes into a preheated flask, add extracted liquid (macerated herb) and seal flask to prevent alcohol fumes from escaping. 

CHROMIUM TRIHYDROXIDE (308-14-1) CrH204 A powerful oxidizer. Violent reaction with many materials, including reducing agents (explosion) hydrides, nitrides, and sulfides acetic acid, acetic anhydride acetone, alcohols, alkalis, alkali metals, ammonia, anthracene, arsenic, combustible materials dimethylformamide, ethers, ethyl alcohol fumes (ignition) finely divided metals hydrogen sulfide sulfuric acid organic matter peroxyformic acid, phosphorus, pyridine, selenium, sodium, sulfur, and other oxidizable materials. 

Synonyms Anisoyl chloride 4-Anisoyl chloride Benzoyl chloride, methoxy- Benzoyl chloride, 4-methoxy- 4-Methoxybenzoic acid chioride p-Methoxybenzoic acid chloride Methoxybenzoyl chloride 4-Methoxybenzoyi chloride p-Methoxybenzoyl chloride Empirical C8H7CIO2 Formula CH3OC6H4COCI Properties Clear cryst. or amber liq. sol. in acetone, benzene, ether dec. by water and alcohol fumes in moist air m.w. 170.60 m.p. 22 C b.p. 262-263 C flash pt. 87 C Toxicology Sol ns. corrosive to tissue (skin, eyes, mucous membranes) lachrymator TSCA listed... 

Lue, S.J., Chen, J.Y. and Yang, J.M. 2008. Crystallinity and stabihty of poly(vinyl alcohol)-fumed silica mixed matrix membranes. Q QHjoL ScL 47(1) 39-51. 

Gun ko, V.M., Pissis, R, Spanoudaki, A. et al. 2007e. Relaxation phenomena in polyfvinyl alcohol)/fumed... 

H2N (CH2]5 NH2. a syrupy fuming liquid, b.p. 178-180 - C. Soluble in water and alcohol. Cadaverine is one of the ptomaines and is found, associated with pulrescine, in putrefying tissues, being formed by bacterial action from the amino-acid lysine. It is found in the urine in some cases of the congenital disease cystinuria. The free base is poisonous, but its salts are not. 

Some alcohols react readily with phenylisocyanate at room temperature, and others require heating, preferably in petroleum. Phenylisocyanate is poisonous and should not be heated outside a fume-cupboard except under a condenser. 

Although these nitrations proceed smoothly, attempted nitration of an unidentified substance should always be carried out with extreme care, e.g., by working in a fume-cupboard and pointing the boiling-tube away from the operator. Many organic substances e.g., alcohols and phenols) react with great violence with a mixture of nitric and sulphuric acids. 

Nitrobenzene is an extremely versatile solvent, and may frequently be employed for the crystallisation of compounds which do not dissolve appreciably in the common organic solvents. The vapour is somewhat poisonous, so that recrystaUisations must be carried out in the fume cupboard. After the crystals have been collected, they should be washed with a volatile solvent, such as benzene, alcohol or ether, to remove the excess of nitrobenzene (compare Section 11,32). The only disadvantage of nitrobenzene as a solvent is that it has a pronounced oxidising action at the boihng point. 

Method 2. Mix 1 0 g. of 3 5-dinitrobenzoic acid with 1 5 g. of phosphorus pentachloride in a small, dry test-tube. Warm the mixture gently over a small smoky fiame to start the reaction when the reaction has subsided (but not before), boil for 1-2 minutes or until the solid matter has dissolved. Pour the mixture while still liquid on a dry watch glass (CAUTION the fumes are irritating to the eyes). When the product has solidified, remove the liquid by-product (phosphorus oxychloride) by transferring the pasty mixture to a pad of several thicknesses of filter paper or to a small piece of porous tile. Spread the material until the liquid has been absorbed and the residual solid is dry. Transfer the 3 5 dinitrobenzoyl chloride to a test-tube, add 0-5-1 ml. of the alcohol, and continue as in Method 1. 

CAUTION. Bromine must be handled with great care and in the fume cupboard. The liquid produces painful bums and the vapour is unpleasant. Bromine bums should be treated immediately with a liberal quantity of glycerine. If the vapour is inhaled, relief may be obtained by soaking a handkerchief in alcohol and holding it near the nose. 

Mix 0-2 g. of 3 5-dinitrobenzoyl chloride, 6 drops of the mercaptan and 1-3 drops of pyridine in a test-tube, and heat the mixture in a beaker of boiling water until fumes of hydrogen chloride cease to appear (15-30 minutes). Add a few drops of water, followed by a drop or two of pyridine to eliminate the excess of the reagent. The product sohdifies upon stirring with a glass rod. Add water, filter, and recrystalUse from dilute alcohol or dilute acetic acid. 

Toluene, Proceed as for Benzene but use 0-5 ml. of toluene and a mixture of 3 ml. of concentrated sulphuric acid and 2 ml. of fuming nitric acid. Gently warm the mixture over a free flame for 1-2 minutes, cool, and pour into 20 ml. of ice water. Recrystalhse the product from dilute alcohol. 2 4-Dinitrotoluene, m.p. 71°, is obtained. 

Diphenyl. Reflux a mixture of 1 g, of diphenyl, 2 ml. of glacial acetic acid and 0 -5 ml. of fuming nitric acid for 10 minutes. Pour into 20 ml. of cold water, filter oflF the precipitate, wash it with cold water imtil free from acid, and recrystallise from alcohol. The product is 4-nitrodiphenyl, m.p. 114°,... 

Place 18 g. (12 ml.) of fuming nitric acid, sp. gr. 1 5, and 30 g. (16-5 ml.) of concentrated sulphuric acid and a few fragments of broken glass in a 250 or 500 ml. round-bottomed flask. Add gradually, in small portions, 14 g. of p-nitrotoluene do not allow the temperature to rise above 50 and cool the flask, if necessary, by immersion in cold water. Place a small funnel in the mouth of the flask and heat on a water bath at 90-95° for 30 minutes. Allow to cool almost to the laboratory temperature and pour the reaction mixture slowly into about 500 ml. of ice water containing a few small pieces of ice. Filter the crude dinitrotoluene through a Buchner funnel at the pump, wash it thoroughly with cold water, and drain as completely as possible. RecrystalUse from the minimum volume of hot methyl alcohol (flask, reflux condenser, and water bath experimental details as in Section IV,12). The yield of pure 2 4-dinitrotoluene, m.p. 71°, is 12 -5 g. 

Add 1 g. of the compound to 4 ml. of concentrated sulphuric acid and cautiously introduce, drop by drop, 4 ml. of fuming nitric acid. Warm the mixture on a water bath for 10 minutes, then pour it on to 25 g. of crushed ice (or 25 ml. of ice water). Collect the precipitate by filtration at the pump, and recrystallise it from dilute alcohol. 

In a 1 litre round-bottomed flask provided with an efficient double surface condenser, place 40 g. (39 ml.) of aniline, 50 g. (40 ml.) of carbon sulphide CAUTION inflammable) (1), and 50 g. (63-5 ml.) of absolute ethyl alcohol (2). Set up the apparatus in the fume cupboard or attach an absorption device to the top of the condenser (see Fig. 11, 8, 1) to absorb the hydrogen sulphide which is evolved. Heat upon an electrically-heated water bath or upon a steam bath for 8 hours or until the contents of the flask sohdify. When the reaction is complete, arrange the condenser for downward distillation (Fig. 11, 13, 3), and remove the excess of carbon disulphide and alcohol (CA UTION inflammable there must be no flame near the receiver). Shake the residue in the flask with excess of dilute hydrochloric acid (1 10) to remove any aniline present, filter at the pump, wash with water, and drain well. Dry in the steam oven. The yield of crude product, which is quite satisfactory for the preparation of phenyl iao-thiocyanute (Section IV.95), is 40-45 g. Recrystalhse the crude thiocarbanihde by dissolving it, under reflux, in boiling rectified spirit (filter through a hot water funnel if the solution is not clear), and add hot water until the solution just becomes cloudy and allow to cool. Pure sj/m.-diphenylthiourea separates in colourless needles, m.p, 154°,... 

Method 1. Place 20 g. of crude benzoin (preceding Section) and 100 ml. of concentrated nitric acid in a 250 ml. round-bottomed flask. Heat on a boiling water bath (in the fume cupboard) with occasional shaking until the evolution of oxides of nitrogen has ceased (about 1 -5 hours). Pour the reaction mixture into 300-400 ml. of cold water contained in a beaker, stir well until the oil crystallises completely as a yellow solid. Filter the crude benzil at the pump, and wash it thoroughly with water to remove the nitric acid. RecrystaUise from alcohol or methylated spirit (about 2-5 ml. per gram). The yield of pure benzil, m.p. 94-96°, is 19 g. 

Methylanthraquinone. Use 10 5 g. of p-toluyl-o-benzoic acid (preceding Section) and 90 g. (46 ml.) of fuming sulphuric acid (20 per cent. SO3). RecrystaUise the product from alcohol in the presence of a little decolourising carbon. The yield of pure p-methylanthraquinone, m.p. 176°, is 7 - 5 g. 

Place 25 g. of phenylacetic acid (Section IV,160) in a 500 ml. round-bottomed flask, cool the latter in running water and add 250 ml. of fuming nitric acid, rather slowly at first and then more rapidly. The addition occupies about 15 minutes. Attach a condenser to the flask, reflux the solution for 1 hour, and pour into about 500 ml. of cold water. When cold, filter the crude 2 4-dinitrophenylacetic acid at the pump and wash it with cold water the resulting acid, after drying at 100°, is almost pure (m.p. 181°) and weighs 31 g. Recrystallise it from 300 ml, of 20 per cent, alcohol. Collect the first main crop (25 g.), and allow the mother liquor to stand overnight when a further 2 g. of pure acid is obtained dry at 100°, The yield of pure 2 4-dinitrophenylacetic acid, m.p. 183°, is 27 g. 

Place an intimate mixture of 125 g. of powdered, anhydrous zinc chloride and 26-5 g. of acetophenonephenylhydrazone in a tall 500 ml. beaker in an oil bath at 170°. Stir the mixture vigorously by hand. After 3-4 minutes the mass becomes hquid and evolution of white fumes commences. Remove the beaker from the bath and stir the mixture for 5 minutes. Then stir in 100 g. of clean, white sand in order to prevent solidification to a hard mass. Digest the mixture for 12-16 hours on a water bath with 400 ml. of water and 12 ml. of concentrated hydrochloric acid in order to dissolve the zinc chloride. Filter off the sand and the crude 2-phenylindole, and boil the solids with 300 ml. of rectified spirit. Treat the hot mixture with a little decolourising carbon and filter through a pre-heated Buchner funnel wash the residue with 40 ml. of hot rectified spirit. Cool the combined filtrates to room temperature, filter off the 2-phenylindole and wash it three times with 10 ml. portions of cold alcohol. Dry in a vacuum desiccator over anhydrous calcium chloride. The yield of pure 2-phenylindole, m.p. 188-189°, is 16 g. 

Dinitroaniline from 3 5-dinItrobenzoic acid. Place a solution of 50 g. of 3 5-dinitrobenzoic acid (Section IV, 168) in 90 ml. of 10 per cent, oleum and 20 ml. of concentrated sulphuric acid in a 1-litre three necked flask equipped with a reflux condenser, mechanical stirrer, adropping funnel, and thermometer (FUME CUPBOARD ). Add 100 ml. of clJoroform and raise the temperature to 45°. Stir rapidly and add 17 -5g. of sodium azide in small portions whilst maintaining the temperature at 35-45°. The reaction is accompanied hy foaming, which usually commences after about 3 g. of sodium azide has been introduced. After all the sodium azide has been added raise the temperature so that the chloroform refluxes vigorously and maintain this temperature for 3 hours. Then cool the reaction mixture, pour it cautiously on to 500 g. of crushed ice, and dilute with 3 litres of water. After 1 hour, separate the yellow solid by filtration at the pump, wash well with water and dry at 100°. The yield of 3 5-dinitroaniline, m.p. 162-163°, is 39 g. The m.p. is unaffected by recrystallisation from dilute alcohol. 

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