Sodium phenolate process

The sodium phenolate process is also of more interest for historical reasons than for practical applications as it has been largely supplanted by other processes. The process, which... 

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... 

Koppers phenolate A process for removing hydrogen sulfide from coal gas by absorption in aqueous sodium phenolate. Invented in 1931 by J. A. Shaw at the Koppers Company, Pittsburgh, but possibly never used. 

Phenoraffin A process for recovering phenols from carbonizer tar and coke-oven tar. The tar is dissolved in aqueous sodium phenolate and extracted with isopropyl ether. 

PHENOLATE PROCESS. A process for removing hydrogen sulfide from gas by the use of sodium phenolate. which reacts with the hydrogen sulfide to give sodium hydrosulfide and phenol. This can be reversed by steam heat to regenerate the sodium phenolate. 

The base or nucleophile in the Dow phenol process is aqueous NaOH that needs to be heated to 300° C, which is only possible at a pressure of 200 bar. This conconction is only just capable of deprotonating chlorobenzene to benzyne or of adding to the latter subsequently. Thus, there is no analogous synthesis of diaryl ethers from sodium phenolates and haloben-zenes. And as expected, the product resulting from the Dow process did not contain more than 15% of diphenyl ether. 

Salicylic acid is used as a raw material for making aspirin, as well as a starting material for dyes and as a pharmaceutical compound. It is made by heating sodium phenolate with carbon dioxide under pressure, and the process is described in several of the standard reference works listed in Chapter 8. Estimate the cost of production. 

Almost all of the cumene produced is consumed by the cumene peroxidation process to phenol and acetone. Aspects of this process resemble the peroxidation processes to propylene oxide already described, except that in this case the final products are formed by an intramolecular rearrangement of the same molecule that is peroxidized rather than by a reaction of a perox-idized molecule with a second component, propylene. In the first stage of the cumene to phenol process a suspension of purified cumene in a dilute solution of sodium carbonate in water is heated to about 110°C under slight pressure. Air is blown through this suspension until about 25% of the cumene has formed the hydroperoxide (Eq. 19.49). 

Phase-Transfer Catalysis. Since the efficiency of the reaction requires that bisphenoi A be used in the form of water-soluble phenolate anions, while phosgene must be dissolved in a chemically inert and hence water-insoluble solvent, the desired reaction would have to depend on the diffusion rate of the two reactants to the interface between the immiscible solvents. The area of the interface can be increased by vigorous stirring of the two-phase reaction mixture, but a more efficient way to accelerate the process is to induce one of the reactants to migrate into a phase that is not particularly receptive to it. In this example, the sodium phenolate ions are in equilibrium with a phase-transfer catalyst such as tetra-n-butylammonium chloride, and while one of the products of the equilibrium (sodium chloride) remains in the aqueous phase, the other products of the equilibrium (the BPA anion-tetra-rc-butylammonium cation ion pairs) are of sufficiently covalent character to migrate into the nonaqueous phase where they encounter phosgene and the reaction takes place. 

Salicylic Acid. 2-Hydmxybenimc acid Keralyt Verrugon. C,H(03 mol wt 138.12. C 60.87%. H 4.38%. O 34.75%. Occurs in the form of esters in several plants, notably in wintergreen leaves and the bark of sweet birch. Made synthetically by heating sodium phenolate with carbon diox -ide under pressure. Large scale process details Faith et at. Industrial t hem [cats (Wiley, New York, 3rd ed.. 1965) pp 652-655. Novel method by microbial oxidation of naphthalene Zajic, Dunlap. U.S. pat. 3,274,074 (1966 to Kcrr-McGee). Toxicity data K. Sota et at. J. Pharm. Soc. Japan 89, 1392 (1969). 

Charles Adolphe Wurtz and August Kekule further improved the process in 1867. The sulfonation route was developed to technical maturity in particular by Bayer and Monsanto. The first stage in the synthesis is the sulfonation of benzene with sulfuric add, generally using a 100% excess of sulfuric acid. In the second stage, the sulfonation product is neutralized with sodium hydroxide or sodium sulfite. The resulting benzenesulfonate, in solid form or as a concentrated aqueous solution, is heated with sodium hydroxide at temperatures of 320 to 340 °C, in cast-iron pans. The alkaline sodium phenolate solution is neutralized ( saturated ) with CO2 or, in the Monsanto process, with SO2. When the water has been distilled off substantially pure phenol with a crystallizing point of 40.5 °C is obtained. 

The presently dominant process for the production of salicylic acid is based on the Kolbe-Schmitt synthesis. Hermann Kolbe and E.Lautemann described the reaction of carbon dioxide with sodium phenolate to produce sodium salicylate and its subsequent reaction with sulfuric acid to yield salicylic acid, in 1860. However, as a result of the formation of di-sodium salicylate in this process, only half the phenol was converted into salicylic acid. Rudolf Schmitt modified the synthesis in 1884, by first bringing into contact carbon dioxide with cold, dry sodium phenolate, then heating the mixture under pressure to 120 to 140 °C. 

In the process commonly used today, carbon dioxide is fed at a pressure of 6 to 7 bar and at a temperature of 100 °C over dry sodium phenolate, which is produced from phenol and 50% aqueous sodium hydroxide solution followed by vacuum evaporation of the water. The reaction mixture is then carboxylated at 150 to 170 °C until no more CO2 uptake occurs. The crude salicylic add is recovered... 

Arynes combine with all kinds of polar compounds such as lithium halide, alcohols, primary, secondary or tertiary amines, phosphines, and boranes. Of practical, even technical, importance are their reactions with metal hydroxides and alkoxides. The conversion of chlorobenzene by sodium hydroxide at 350 °C into sodium phenolate, an industrial process, obeys the elimination/addition mechanism. Again arynes can be postulated as plausible intermediates. Regardless of which isomer of bromophenol or of bromophenyl benzenesulfonate is heated with sodium hydroxide, resorcinol is always isolated as the main or sole product after neutralization. 

Bright yellow needles m.p. 45 C, b.p. 2 4°C. Prepared together with 4-nitrophenol by careful nitration of phenol. Sodium sulphide reduces it to 2-aminophenol which is used in dyestuffs and photographic processes. 

Obtained synthetically by one of the following processes fusion of sodium ben-zenesulphonate with NaOH to give sodium phenate hydrolysis of chlorobenzene by dilute NaOH at 400 C and 300atm. to give sodium phenate (Dow process) catalytic vapour-phase reaction of steam and chlorobenzene at 500°C (Raschig process) direct oxidation of cumene (isopropylbenzene) to the hydroperoxide, followed by acid cleavage lo propanone and phenol catalytic liquid-phase oxidation of toluene to benzoic acid and then phenol. Where the phenate is formed, phenol is liberated by acidification. 

After cleavage the reaction mass is a mixture of phenol, acetone, and a variety of other products such as cumylphenols, acetophenone, dimethyl-phenylcarbinol, a-methylstyrene, and hydroxyacetone. It may be neutralised with a sodium phenoxide solution (20) or other suitable base or ion-exchange resins. Process water may be added to facilitate removal of any inorganic salts. The product may then go through a separation and a wash stage, or go direcdy to a distillation tower. 

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