Phenol removal with ammonia solutions

Type 1. In this case the mass transfer rate through the membrane phase is increased by incorporating a stripping agent in the internal phase which reacts with the solute yielding a membrane insoluble product. Examples of this system are extraction of weak acids or bases from wastewater such as phenol removal by NaOH solution as the internal phase [3-8] and removal of ammonia by H2SO4 solution as the internal phase [9-10]. 

Colorations or coloured precipitates are frequently given by the reaction of ferric chloride solution with.(i) solutions of neutral salts of acids, (ii) phenols and many of their derivatives, (iii) a few amines. If a free acid is under investigation it must first be neutralised as follows Place about 01 g. of the acid in a boiling-tube and add a slight excess of ammonia solution, i,e., until the solution is just alkaline to litmus-paper. Add a piece of unglazed porcelain and boil until the odour of ammonia is completely removed, and then cool. To the solution so obtained add a few drops of the "neutralised ferric chloride solution. Perform this test with the following acids and note the result ... 

The rate of stripping or the stripabiUty on cataly2ed urethane and epoxy resin finishes can be increased by adding formic acid, acetic acid, and phenol. Sodium hydroxide, potassium hydroxide, and trisodium phosphate [10101-89-0] may be added to the formula to increase the stripabiUty on enamel and latex paints. Other activators include oleic acid [112-80-17, trichloroacetic acid [76-85-9], ammonia, triethanolamine [102-71-6], and monoethyl amine. Methylene chloride-type removers are unique in their abiUty to accept cosolvents and activators that allow the solution to be neutral, alkaline, or acidic. This abihty gready expands the number of coatings that can be removed with methylene chloride removers. 

Carefully scrape the separated bromophenol blue spots on to a sheet of clean smooth-surfaced paper using a narrow spatula (this is easier if two grooves are made down to the glass on either side of the spots). Pour the blue powder into a small centrifuge tube, add 2 mL of ethanol, 5 drops of 0.880 ammonia solution, and stir briskly until the dye is completely extracted. Centrifuge and remove the supernatant blue solution from the residual white powder. Repeat this procedure with the separated Congo red and phenol red spots . 

Acid or base can be used as an internal phase or stripping phase for ELM process depending upon solute to be extracted, for example, Cahn and Li [3] used NaOH solution as the internal phase for phenol removal from wastewater. H2SO4 solution was used as the internal phase for removal of ammonia [4-8]. The solute extraction rate also increases with an increase in the amount of internal reagent present in the emulsion. 

Test for phenolic resins. The test material (dry) is heated in an ignition tube over a small flame. The mouth of the tube is covered with a filter paper, prepared by soaking it in an ethereal solution of 2,6-dibromoquinone-4-chloro-imide and then drying it in air. After the material has been pyrolyzed for about a minute, the paper is removed and moistened with 1-2 drops of dilute ammonia solution. A blue color indicates phenols (care must be taken with plastics that contain substances yielding phenols on pyrolysis, e.g., phenyl and cresyl phosphate, cross-linked epoxide resins, etc.). 

Typically, reaction is carried out batch-wise in a stirred reactor, jacketed for heating and cooling. The reactor is also fitted with a condenser such that either reflux or distillation may take place, as required. A mixture of phenol, formalin and ammonia (about 1-3% on the weight of phenol) is heated under reflux at about 100°C for 0.25-1 hour and then water is removed by distillation under reduced pressure (to limit further reaction). Distillation is continued until a cooled sample of the residual resin has a melting point in the range 45—50°C. The resin is then quickly discharged and cooled to give a hard, brittle solid. In an alternative procedure, the removal of water is not taken to completion but is halted when the resol content of the residual aqueous solution reaches about 70%. The solution is then used directly, mainly in the preparation of paper laminates. In the preparation of such aqueous solutions, the preferred catalyst is... 

Consider an oily membrane without any acidic cation exchanger (see Problem 5.2.8). Through such a membrane, which may be a liquid or a polymeric membrane, it is possible to remove ammonia NH3 (1 = 1), but not the ammonium ion NHj (i = 2). In a process somewhat analogous to that described for phenol removal in Sections 5.4.3 and 5.4.4, the feed solution is basic (pH > 10) small amounts of ammonia in the feed Q =f) permeate through the membrane to the other side (j = p), where there is a highly acidic solution to react with the ammonia. 

Gibb s ludophcnol test for Phenol Immerse a filter paper in a saturated solution of 2,6-dibromoquiiione 4-chlorimide in ether and then dry in air. Place the sample in a pyrolysis tube and cover its mouth with the pajter prepared above. Heat the tube for 1—2 minutes. Remove the paper and moisten with 1-2 drops of ammonia solution. A blue colour indicates the presence of phenol (PF, PC, EP). 

C) Phenacyl and p-Bromophenacyl esters. Ammonium salts in aqueous-ethanolic solution do not however usually condense satisfactorily with phenacyl and />-bromophenacyl bromide. The aqueous solution of the ammonium salt should therefore be boiled with a slight excess of sodium hydroxide to remove ammonia, and the solution then cooled, treated with hydrochloric acid until just alkaline to phenol-phthalein, and then evaporated to dryness. The sodium salt is then treated as described (p. 349) to give the ester. Filter the ester, and wash with water to remove senium halide before recrystallisation. 

Potassium carbonate. Solid potassium hydroxide is very rapid and efficient. Its use is limited almost entirely to the initial drying of organic bases. Alternatively, sometimes the base is shaken first with a concentrated solution of potassium hydroxide to remove most of the water present. Unsuitable for acids, aldehydes, ketones, phenols, thiols, amides and esters. Also used for drying gaseous amines and ammonia. 

Ammonia stripping also removes cyanide, phenols, and other VOCs typically found in cokemaking wastewater. Phenols may also be removed by conversion into nonodorous compounds or into crude phenol or sodium phenolate by either biological means (phenol concentration <25 mg/L) or by physical processes.21 However, the Koppers dephenolization process is considered to be quite effective as it lowers the phenol content by 80 to 90% in ammonia still wastes. In this process a stream stripping process followed by mixing in a solution of caustic soda results in renewal of pure phenol with the flue gas.8... 

A problem encountered with the use of the phenolic oximes in Ni recovery from ammoniacal solution is the co-extraction of ammonia that must be removed prior to generating the electrolyte for... 

Haplophytine is a very weak acid, but it is apparent from its behavior that it contains neither carboxylic acid nor simple phenolic groupings. For example, chloroform extracts haplophytine from its solution in 0.2 N sodium hydroxide, but normal sodium hydroxide removes haplophytine from its solution in chloroform. Evaporation of its solutions in baryta or ammonia yields only haplophytine (2). That the weakly acidic center is contained in a cryptophenolic grouping is established by the following observations. Haplophytine reacts slowly with diazomethane to give a nonacidic O-methyl ether, mp 288°-291°, [a] +12° (chloroform),... 

Phenol and Ammonia Recovery. Finally, the closely related passive and fa-cilitated-transport processes for phenol and ammonia recovery should be mentioned. In these processes, dilute phenol or ammonia feed solutions are contacted with a liquid membrane in which they are freely soluble. They dissolve in the membrane, diffusing to the product side where they are removed by neutralizing with a base (in the case of phenol) or an acid (in the case of ammonia). Although the transport mechanism does not involve a carrier and these are, therefore, passive transport processes, the actual process is quite similar, and Li et al25 published the details of these separations using emulsion membrane technique. 

A quantity of freshly distilled POCI3 (154 g.) is refluxed for 2-3 hours with 188 g. of freshly distilled phenol. The product is kept overnight in vacuum over NaOH to remove additional HCl. The oily liquid is added by drops to a minimum of 300 ml. of absolute alcohol, presaturated with NH3 at 0°C. The reaction flask is ice-cooledand vigorously stirred. The mixture must be ammonia-cal at the end of the reaction. The alcoholic solution is poured into five times its volume of ice water. The precipitate of the diphenyl ester of monoamidophosphoric acid is filtered off by suction, freed of adhering oil by pressing on clay, and dried in vacuum. The crude ester (approximately 160 g.) is recrystallized from 200 ml. of alcohol. The yield is approximately 100 g. (m.p. 148°C). An additional 50 g. of impure ester can be obtained by precipitation of the alcoholic mother liquor with water. 

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