Potassium hydroxide sulfur removal

Possible surface treatment mechanisms include anodization [32-34], plasma and flame treatment [35], solution oxidation [36,37], gas phase oxidation, and high temperature oxidation. Some of these treatments have been reviewed 1 Donnet and coworkers [18,38]. The most practical surface treatment for commercial production of carbon fibers is anodization. This is because anodization (electrolytic oxidation) can be performed continuously on carbon fibers. Typical anodizations have been performed in aqueous acidic or basic solutions. Electrolytes include sodium hydroxide, potassium hydroxide, sulfuric add, nitric add, and solutions of amine salts. Amine salts have an added advantage in that, after treatment, excess electrolyte can be removed simply by heating the fiber to high temperatures (250 C). 

The almost dry residue is cooled to 0°C and made strongly alkaline with a 50% potassium hydroxide solution. The amine is extracted into several portions of ether, dried over potassium hydroxide, the solvent removed, and the base fractioned. Reaction of the base with a half-molar quantity of sulfuric acid gives the sulfate. 

Recently a colorimetric test for methoxychlor residues was proposed by Fairing (27). The methoxychlor sample is treated with alcoholic potassium hydroxide, the reaction product is extracted with ether, the ether is removed, and the residue is treated with concentrated sulfuric acid. An intense cherry-red color is developed. No other insecticide has been found to interfere, and the reaction is sensitive to about 5 micrograms of methoxychlor. 

In a sensitive and specific colorimetric method 1,1,1-trichloro-2,2-bis(p-methoxyphenyl)-ethane is extracted from plant or animal tissue, using benzene or petroleum ether as the solvent. The solvent is evaporated at room temperature by a current of air and the residue dehydroha log ena ted with 2% alcoholic potassium hydroxide. By petroleum ether extraction the resulting 1,1-dichloro-2,2-bis(p-methoxyphenyl)-ethylene is removed from the reaction mixture. After the solvent is removed by air evaporation the dehydroha log ena ted methoxychlor is isolated from the nonsaponifiable portion of the fats and waxes by dissolving the residue in hot acetone, chilling, and filtering. After the acetone is removed by air evaporation, the residue is treated with 85% sulfuric acid. This produces a red solution with an absorption maximum at 555 m/z, the intensity of which can be read on a colorimeter and is a function of the methoxychlor concentration. Beer s law is obeyed over the range of 1 to 50 micrograms. 

A. l-Phenyl-2,2,2-lrichloroethanol. In a 1-1. round-bottomed-flask fitted with a mechanical stirrer, a thermometer, and a powder funnel is placed a solution of 212 g. (2.00 moles) of freshly distilled benzaldehyde in 400 g. (270 ml., 3.35 moles) of chloroform. The mixture is cooled in an ice bath, and 123 g. of commercial powdered potassium hydroxide is added with stirring at such a rate that the temperature of the solution does not exceed 45° (1-1.5 hours). The reaction mixture is stirred and kept at 40-50° for an additional hour and then poured into a solution of 60 ml. of sulfuric acid in 3 1. of water. The resulting two-phase mixture is transferred to a separatory funnel and extracted with three 250-ml. portions of chloroform (a small amount of insoluble, black resinous material is discarded). The combined organic layers are washed with three 100-ml. portions of aqueous 10% sodium carbonate, dried over anhydrous magnesium sulfate, and filtered into a 1-1. flask. The solvent is removed under reduced pressure on a hot water bath. The residue is transferred to a 250-ml. flask and distilled under reduced pressure to give l-phenyl-2,2,2-trichloroethanol, b.p. 155-165° (26 mm.), 90-100° (0.5 mm.) (Notes 1 and 2). The yield is 170-180 g. (38-40%). 

The methods used to purify the solvents were as follows. The early batches of ethanol were subjected to a somewhat lengthy series of fractionations involving successive treatment with sulfuric acid, silver nitrate and potassium hydroxide, and aluminium-mercury couple. However, the following simple procedure was found to give equally good results. Three grams of potassium hydroxide pellets were rinsed with ethanol to remove surface impurities and added to 3 liters of boiling ethanol. The ethanol was then immediately fractionated and the middle 50% collected. The n-hexane and the isopentane were purified by ex-... 

The protein used was crystalline bovine serum albumin (BSA) obtained from Armour Laboratories. Sodium dodecyl sulfate (SDS) was synthesized from pure dodecyl alcohol and chlorosulfonic acid, recrystallized, and washed with ethyl ether. Sulfuric acid was reagent grade purchased from the J. T. Baker Chemical Co. and used directly. Reagent grade potassium hydroxide purchased from the Mallinkrodt Co. was purified by foaming a concentrated solution, removing the foam, and using the solution directly. 

In a 500-cc. three-neck flask, fitted with a reflux condenser and a mechanical stirrer (Note t), is placed 45.5 g. (0.25 mole) of 2,4-dinitrotoIuene (Note 2), 85 g. (1.5 moles) of iron (Note 3), and 100 cc. of 50 per cent (by weight) ethyl alcohol (Note 4). The mixture is heated to boiling on a water bath, the stirrer is started (Note 5) and a solution of 5.2 cc. (0.06 mole) of concentrated hydrochloric acid in 25 cc. of 50 per cent (by weight) ethyl alcohol is added slowly (Note 6). The mixture is refluxed for two hours after addition of the acid is complete. At the end of this time the apparatus is disconnected and the hot mixture is made just alkaline to litmus by the addition of the calculated amount of 15 per cent alcoholic potassium hydroxide solution (Note 7). Without allowing the mixture to cool, the iron is removed by filtration and the reaction flask is rinsed with two 50-cc. portions of 95 per cent ethyl alcohol the same alcohol is used to wash the iron residue. To the filtrate is added 84 cc. of 6 N sulfuric acid the normal sulfate of 2,4-diaminotoluene precipitates. The mixture is cooled to 250 and filtered by suction. The product is washed with two 35-rc. portions of 95 per... 

II). trans-m-Bromocinnamic acid (14.8 g), ethanol (173 ml) and concentrated sulfuric acid (0.4 ml) were combined and heated at reflux for 15 hours. About 150 ml of the ethanol was distilled off, and the remaining solution was poured into ice/water (140 ml). The cold mixture was made strongly alkaline with 40% sodium hydroxide and extracted with methylene chloride (4x60 ml). The combined methylene chloride extract was dried over anhydrous potassium carbonate. The potassium carbonate was removed by filtration and the solvent stripped off under reduced pressure. trans-ethyl-3-Bromocinnamate, was obtained as a partially solidified oil. (IR spectrum was consistent with this compound). 

Cs[(C2BqH11)2Co] are dissolved in 20 ml of acetic anhydride, 3.4 g (25 mmol) of powdered tellurium followed by 2 ml of concentrated sulfuric acid are added, and the mixture is heated at 100° for 4h, then filtered. Most of the acetic anhydride is removed from the filtrate at 80° (bath temperature)/10 torr. The residue is shaken with a mixture of 50 ml of water plus 50 ml of benzene, the aqueous layer is separated and discarded. The benzene is distilled under vacuum from the remaining non-aqueous phase, the residue is dissolved in 50 ml of acetone, and this solution is poured into 60 ml of methanol containing 6.0 g of potassium hydroxide. 2 ml of dimethyl sulfate are added, the mixture is shaken for 10 min, and excess dimethyl sulfate is removed by shaking the mixture with 10 ml of 15% aqueous ammonia. 50 ml of benzene and 200 ml of water arc added, the orange-colored benzene layer is separated, washed with two 50 ml portions of water, and filtered. The filtrate is concentrated to a volume of 10 ml, and poured onto a column containing 100 g of silica gel which is then eluted with benzene/hexane (1/1, v/v). The red band with Rt = 0.2 is separated mechanically, extracted with benzene, and the extract is concentrated to a volume of 10 ml. The viscous residue is covered with a layer of hexane and red needles separate overnight yield 0.15 g (3%). 

The ester is hydrolyzed by heating under reflux for 1.5 hours with 50 ml. of 95% ethanol and 4.4 g. of 85% potassium hydroxide (0.066 mole) for each 10 g. (0.044 mole) of ester. Two-thirds of the ethanol is removed by distillation then the residue is diluted with five volumes of water and acidified to Congo red with 5 N sulfuric acid. The organic acid is extracted with two... 

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