Decolorization water

SchifT s reagent A solution of rosaniline in water decolorized with sulphurous acid. Aliphatic aldehydes and aldose sugars give a magenta colour with this reagent with aromatic aldehydes and aliphatic ketones the colour develops more slowly aromatic ketones do not react. 

The toluene solution from the previous step was treated with an ethanol solution of NaOEt (0.1 mol in 100 ml) at O C. When about a quarter of the solution had been added a thick precipitate formed and ether (100 ml) was added to maintain a fluid slurry. The remainder of the NaOEt was added and the slurry was stirred overnight. The solid was collected and w ashed with ether. It was then mixed with ether (200 ml) and 2NHC1 (75 ml) and shaken in a separatory funnel until the solid dissolved. The ether layer was washed with 2NHHC1 (2 X 50ml) and water and dried over MgS04. The solution was decolorized with Magnesol and evaporated to give the a-nitro ester as a red oil. 

GaUic acid is heated with about half its weight of water in a copper autoclave until the pressure reaches 1.2 MPa (12 atm) and the temperature is 175°C. Steam and carbon dioxide are released but sufficient water is retained to maintain the pyrogaHol as a Hquid. The cooled solution is decolorized with animal charcoal and is then evaporated until the volatile pyrogaHol distills into iron receivers. The sohdified material is purified by repeated distillation, sublimation, or vacuum distillation at 200°C in the presence of diaLkyl phthalates (8). 

C), the yield of more than 90% purity L-glutamic acid crystals is very high. The glutamic acid crystals appear as both the metastable a- and stable P-forms. The a-form consists of prismatic crystals which are easy to filter, whereas the P-form needle crystals are difficult to filter. Control of crystallisation conditions of a-crystals are requited (13). The cmde L-glutamic acid crystals are suspended ia water and neutralized with caustic soda or sodium hydroxide. The solution is decolorized with activated carbon to produce a transparent solution and MSG is crystallized under reduced pressure. 

In a 500-cc. round-bottom flask fitted with a reflux condenser are placed 68 g. of phenylurea (0.5 mole) (Note i) and 120 cc. (i mole) of 42 per cent hydrazine hydrate solution (Note 2). The flask is heated on a steam bath for about twelve hours. The hot mixture is treated with a small amount of decolorizing charcoal (Norite) and filtered. The charcoal is washed with two 15-CC. portions of warm water and the filtrate and washings are then concentrated on a steam bath to about 100 cc. On coolipg in an ice bath a crop of crystals separates and is collected on a filter and washed with two 15-cc. portions of cold water. The filtrate and washings are concentrated to about 25 cc. and another crop of crystals is obtained as before. The total yield of crude compound is 47-52 g. It is white at first but sometimes turns brown on drying. It usually melts below 115° because of some unchanged phenylurea. 

The free base tends to become oxidized in the air but may be preserved as the hydrochloride. This is prepared by transferring it as soon as possible to 1500 cc. of distilled water containing 100 cc. of concentrated hydrochloric acid. The sparingly soluble hydrochloride separates at once. It is recrystallized from the mixture with the use of a little decolorizing carbon, whereupon it separates as colorless needles. A further crop is obtained on concentrating the mother liquor under reduced pressure to about 200 cc. The yield is no g. (82.1 per cent of the theoretical amount). 

The crude acid is dissolved in 300 cc. of hot water, boiled with 4-5 g. of decolorizing charcoal for a few minutes, and the solution filtered. After cooling thoroughly under the tap the purified product is filtered with suction and washed with 10-15 c. of cold water. The purified acid weighs 35-40 g. (70-80 per cent of the theoretical amount) and melts at 211-212°. 

C. Saponification. The ester is saponified by refluxing for 5 hours with 75 ml. of a 10% sodium hydroxide solution containing 3 ml. of ethyl alcohol it is then poured into 150 ml. of water and decolorized with Norite. Upon acidification of the alkaline solution with dilute hydrochloric acid, 18-19 g. (40-43%) (Notes 7 and 8) of acid is obtained, melting at 191-193° (corr.). 

To 40 g. of dry chitin in a 500-ml. beaker is added 200 ml. of concentrated hydrochloric acid (c.p., sp. gr. 1.18), and the mixture is heated on a boiling water bath for 2.5 hours with continuous mechanical agitation. At the end of this time solution is complete, and 200 ml. of water and 4 g. of Norite are added. The beaker is transferred to a hot plate, and the solution is maintained at a temperature of about 60° and is stirred continuously during the process of decolorization. After an hour the solution is filtered through a layer of a filter aid such as Filter-Cel. The filtrate is usually a pale straw color however, if an excessive color persists, the decolorization may be repeated until the solution becomes almost colorless. The filtrate is concentrated under diminished pressure at 50° until the volume of the solution is 10-15 ml. The white crystals of glucosamine hydrochloride are... 

The alcoholic filtrate is evaporated to 50 cc., and 50 g. of barium hydroxide and 150 cc. of distilled water are added (Note 4). The mixture is refluxed for two hours and the excess barium hydroxide is precipitated with carbon dioxide. The barium carbonate is removed by filtration and washed with hot distilled water. A slight excess of sulfuric acid is added to the filtrate to liberate the amino acid from its barium salt, and an excess of barium carbonate is added to remove sulfate ion. The mixture is digested on the steam bath until effervescence ceases, and it is then filtered and the precipitate is washed with hot distilled water. The filtrate and washings are concentrated on the steam bath to a volume of 100 cc., decolorized with i g. of active carbon, filtered, and concentrated to the point of crystallization (about 25 cc.). The amino acid is precipitated by the addition of 150 cc. of absolute alcohol and the product is collected and washed with absolute alcohol. 

Although this material is suitable for most purposes, it may be purified further in the following manner. It is dissolved by heating in a solution of 2 g. of stannous chloride and 2 cc. of concentrated hydrochloric acid in i 1. of water, and the hot solution is clarified by filtration through a 5-mm. mat of decolorizing carbon (Note g). The yellow or red color which may develop disappears on reheating to the boiling point. After the addition of 100 cc. of concentrated hydrochloric acid the solution is allowed to cool in an ice bath, treated with a second roo cc. of acid, cooled to 0°, and collected and washed as befor The ciystalline product is colorless, ash-free, and of analytical purity. The loss in the crystallization of an 80-g. lot amounts to 5-10 g. (6-12 per cent). 

A solution of 66.5 g. (1.01 moles) of 85% potassium hydroxide in 300 ml. of water in an 800-ml. beaker is heated to 60-70 , and 100 g. (0.505 mole) of commercial 1,8-naphthalic anhydride (Note 1) is stirred in. The pH of the resultant deep-brown solution is adjusted to a value of 7 (Note 2) with 6N hydrochloric acid and 3N potassium hydroxide. It is treated with 10 g. of decolorizing carbon and filtered. This operation is repeated. The filtrate is concentrated in a 1.5-1. beaker on a steam bath to about 180 ml. The concentrate is cooled to room temperature, 800 ml. of methanol is added with vigorous stirring by hand, and the mixture is cooled to 0-5°. The precipitated dipotassium naphthalate is separated by filtration, washed with 150 ml. of methanol, and dried in a vacuum oven at 150°/150 mm. The dried cream-colorcd salt weighs 130 135 g. (88 92%). 

The autoclave is cooled to room temperature, and the carbon dioxide is bled off. The solid reaction product is taken from the autoclave, pulverized, and dissolved in 1 1. of water at 50-60°. Ten grams of decolorizing carbon is added, and the mixture is stirred well and filtered to remove cadmium salts and carbon. The filtrate is heated to 80-90° and acidified with concentrated hydrochloric acid to pH 1 (Note 5). 2,6-Naphthalenedicar-boxylic acid precipitates. It is separated from the hot mixture by filtration. It is then suspended in 500 ml. of water at 90-95° (Note 5), separated by filtration, and washed successively with 300 ml. of water, 300 ml. of 50% ethanol, and 300 ml. of 90% ethanol. After being dried at 100-150°/150 mm. in a vacuum oven, the 2,6-naphthalenedicarboxylic acid weighs 42-45 g. (57-61%). It decomposes on a heated block at 310-313°. 

Develop a detailed process scheme for decolorizing recycle water used in a fabric dyeing operation. Assume the operation to be continuous. Develop a detailed list of all parameters that impact on the operation of a carbon filter. 

At present, chlorine dioxide is primarily used as a bleaching chemical in the pulp and paper industry. It is also used in large amounts by the textile industry, as well as for the aching of flour, fats, oils, and waxes. In treating drinking water, chlorine dioxide is used in this country for taste and odor control, decolorization, disinfection, provision of residual disinfectant in water distribution systems, and oxidation of iron, manganese, and organics. The principal use of chlorine dioxide in the United States is for the removal of taste and odor caused by phenolic compounds in raw water supplies. 

Fullerols, C6o(OH) (n = 24-26), can be synthesized directly by aerobic oxidation of a benzene solution of Qq using an aqueous solution of NaOH containing a few drops of BimNOH as the most efficient catalyst the deep violet benzene solution rapidly decolorizes and a brown sludge precipitates further reaction with more water over a period of 10 h gives a clear red-brown solution from which the... 

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