INDUSTRIAL A N D ENGINEERING CHEMISTRY
530
T’ol. 19. KO. 4 .
Rapid Determination of Phenol in Ammonia Liquor and Other Solutions’ By Ralph D. Williams HUDSON VALLEYCOKE&
PRODUCTS CORP.,TROY, pi. Y .
T
HIS determination is based on the quantitative precipitation of phenol and its homologs from an aqueous solution by bromine as the bromophenols, followed by determination of the unused bromine.2 This reaction has been described repeatedly in the literature, but a careful purification from interfering substances must be carried out in order to apply it as an accurate control method. The location of a by-product coke works on the Hudson River only about six miles above the cities of Albany and Rensselaer, which take their water supplies from the stream, has made necessary the careful elimination of phenols from its waste liquors. The phenol extraction plant, which removes phenols from ammonia liquor by the benzene extraction method, has been de~cribed.~As in all control work, rapid analytical methods are highly desirable, and in this case must be standard and accurate. The method described herein was evolved in this laboratory to meet these demands. Four classes of solution are met in practice: (1) ammoniacal liquor; (2) ammonia still waste; (3) benzene containing varying quantities of phenols; and (4) sodium phenolate solution equivalent to a wide variety of sodium hydroxide and phenol concentrations, from sodium hydroxide solution (30 per cent) containing a trace of phenols to sodium hydroxide solution which has been saturated with phenol (sodium phenolate solution). The method described can be applied with almost equal facility to each. The impurities in these solutions which react with bromine, and hence must be removed, are: (1) ammonia,which is expelled by boiling in the presence of an excess of sodium hydroxide until the offcoming vapors are no longer alkaline to moist red litmus paper; (2) cyanide, which probably hydrolyzes on boiling but is surely converted to the cyanate by adding a few drops of ammonium polysulfide before boiling; (3) sulfide may be oxidized by the use of a small quantity of hydrogen or sodium peroxide, but precipitation as lead sulfide by the addition of lead oxide or carbonate is best since the final step in the purification is neutralization of the sodium hydroxide present with excess sodium bicarbonate; this is followed by distillation. Phenols, which are insoluble in boiling sodium carbonate solution, come over with the distillate. Apparatus and Reagents
The purification can best be carried out in the same flask as used for distillation, preferably Kjeldahl flasks of 350and 500-cc. capacity. An apparatus similar to the one usually recommended for ammonia distillations with six Kjeldahl flasks, spray traps, and condensers dipping into water in 500-cc. glass-stoppered Erlenmeyers, has proved to be highly sati~factory.~ The necessary reagents are: standard 0.1 N bromine (2.784 grams potassium bromate, 10 grams potassium bromide per liter), 0.1 N sodium thiosulfate (24.82 grams crystals per liter), concentrated hydrochloric acid, pulReceived November 29, 1926. Koppeschaar, 2. anal. Chcm., 10, 233 (1876). * Crawford, THISJOURNAL, 18, 313 (1926). ‘Vorce, I b i d . , 17, 751 (1925). 1 2
verized crystals of potassium iodide, starch solution, 20 per cent sodium hydroxide solution, powdered lead carbonate, C. P. sodium bicarbonate, 30-mesh sand, and castor oil. Analytical Procedure
RAWWEAK LIQUoR-?hfeasure 25 cc. into a 350-cc. Kjeldah1 flask, add 5 cc. of 20 per cent NaOH and 25 cc. of water. Boil off ammonia until vapors have no effect on moist red litmus paper. Add 1 gram lead carbonate and boil 1 minute longer. Weigh out 15 grams of sodium bicarbonate and add to contents of flask. Make up volume to 75 cc., add a few grains of sand to prevent bumping, a drop of castor oil to stop frothing, and distil 50 cc. of it. Repeat twice with addition of 25 cc. distilled water each time. Cool the receiving flask under tap or in a trough. Add 50 cc. of 0.1 N bromine solution and 5 cc. of concentrated hydrochloric acid. Allow to stand in the cooling trough for 15 minutes, then add 2 grams potassium iodide, and titrate with 0.1 N thiosulfate adding starch toward the end as the iodine color fades. Calculate all phenols as phenol, using 1 cc. 0.1 N bromine equivalent to 0.00156 gram phenol. Express either as per cent by volume or grams per liter. (Weak liquor runs about 2 grams phenol per liter.) DEPHENOLIZED WEAK LIQUOR-Measure a 1oo-cc. sample into a 500-cc. Kjeldahl flask, add 10 cc. of 20 per cent sodium hydroxide. Evaporate to 50 cc. volume. Add 2 grams of lead carbonate and boil one minute longer. Add 25 grams of sodium bicarbonate. Finish as in Raw Liquor, using 10 to 20 cc. 0.1 iV bromine solution. AMMONIA STILLWAsm--T;se a 100-cc. sample, 5 cc. 20 per cent sodium hydroxide solution, 1 gram lead carbonate, and finish as in the determination on Dephenolized Weak Liquor. PHENOLIZED BENZENE (about the same amount of phenols present as in Raw Weak Liquor)-Extract 25 cc. of the oil in a 100-cc., pear-shaped separatory funnel with one 10-cc. and two 5-cc. portions of 20 per cent sodium hydroxide. Follow the NaOH extraction with one water wash of about 20 cc. Make up to 50 cc. in a 350-cc. Kjeldahl. Boil off the traces of benzene which have been dissolved. Add 0.5 gram lead carbonate and 25 grams sodium bicarbonate, as for Dephenolized Liquor. Distil into a glass-stoppered Erlenmeyer. For determination of phenols use from 10 to 25 cc. of the 0.1 N bromine. DEPHENOLIZED BENzENE-same as Phenolized Benzene except that only 5 to 10 cc. of 0.1 N bromine are necessary. SODIUM PHENOLATE SOLUTION (containing varying amounts of phenols)-Dilute a convenient portion to larger volume in a volumetric measuring flask, and take a suitable aliquot so as to titrate about 0.05 gram phenol equivalent in the final step. OTHERUSEFULTESTS (in control of benzene extraction process for phenols)-Daily determinations of ammonia in both raw and dephenolized liquor are necessary. Distillation of the benzene circulation will give the amount of tarry matter picked up from the liquor while an accurate daily determination of specific gravity of this benzene also affords an indication as to its quantity. Specific gravity
April, 1927
INDUSTRIAL A N D E,VGI;VEERING CHEMISTRY
and sodium hydroxide by titration using phenolphthalein as indicator are necessary to determine the strength of the sodium phenolate. The writer has found that sodium phenolate is titratable using phenolphthalein as an indicator up to about 85 per cent its sodium hydroxide equivalent. This should also be determined a t least daily. A very good indication of the amount of phenols in sodium phenolate may be had by measuring 50 cc. of the solution into a beaker,
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boiling to expel small amounts of benzene which are sometimes present, cooling, and liberating the phenols with 25 per cent sulfuric acid in a graduate. When neutralizing sodium phenolate with sodium bicarbonate both the amount of bicarbonate necessary and the extent to which the reaction has gone toward completion can be determined by the usual double indicator method for carbonate-hydroxide and carbonate-bicarbonate mixtures.
Direct Determination of Hydrocarbon in R a w Rubber, Gutta-percha, and Related Su bstances'jz By A. R. Kemp BELL TELEPHONE LABORATORIES, N E W
YORK,
N. Y
Iodochloride in glacial acetic acid is shown to be a were much better. On the N S A T U R A T I O N is suitable reagent to determine the unsaturation of the other hand, it was practically one of the outstanding hydrocarbon in rubber or gutta-percha. The influence impossible to obtain satischemical properties of of time, temperature, sunlight, and reagent concenfactory end points owing to rubber and gutta-percha. Up tration upon the reaction is shown. the formation of emulsions, t o the present time there has Comparisons are made between iodochloride, iodoas was the case in the Lewis been no satisfactory method bromide and bromine relative to their reactions with and McAdams methode6 It for determining this property. raw rubber and some of the terpenes. was found that carbon biBromine absorption methods Results of analyses of several rubber and gutta-percha sulfide was an excellent solhave been widely used to samples are given. vent for the rubber iodoestimate the unsaturation of The effects of mastication and heat upon the unchloride and that there was organic compounds, but they saturation of raw rubber are shown. practically no tendency for have proved unsatisfactory emulsions to form with this for rubber. V a ~ b e l Kirch,~ hof,* and Schmitz5 attempted to estimate rubber volumet- solvent, thus making it possible to determine accurately rically by bromine absorption methods, but without success. the unsaturation of rubber hydrocarbon by a rapid voluSome of t'he difficulties cited were-variations of results metric procedure. Further, it was found that under proper with time, substitution with liberation of hydrobromic acid, conditions no substitution took place with the iodochloride and poor end points due to occlusion of bromine by pre- reagent, thus making it unnecessary to apply the McIlhiney? cipitation of the tetrabromide. Lewis and McL4dams6were procedure, as must be done when bromine is used. more successful in applying the McIlhiney7 modification Procedure for Raw Rubber, Gutta-percha, Balata, Etc. of the bromine absorption method. However, this method was reported upon unfavorably by Fisher, Gray, and MerlingS d O.k-gram sample of the material, from which the resins on account of the precipitation of the tetrabromide and the have been removed by extraction with acetone, or any formation of bad emulsions during titration which interfere other suitable method, is cut into small pieces and allowed with the end point, thus making it impossible to obtain to swell overnight in 75 cc. of purified carbon disulfide. concordant results. (The ordinary C. P. carbon bisulfide was purified by allowing A search of the literature failed to reveal any attempt it t'o stand in contact with solid potassium hydroxide for to apply the well-known methods of Wijs and Hanus to 48 hours and finally distilling over same.) Twenty-five rubber. I n an attempt to apply the standard Wijs method cubic centimet'ers of 0.2 N Wijs solutiong are then added to a sample of crepe rubber, very discordant values were from a pipet, and the flask is manipulated in such a way obtained which were very much less than the theoretical as to give a rotating motion to the rubber solution, thus value for rubber hydrocarbon calculated on the basi; of one preventing the formation of a precipitate. After the addition double bond for each CsHs group. It was observed, when of the TT7ijs reagent a clear dark-red solution should result. the Wijs solution was added to 0.1 gram of smoked-sheet The stoppers are then wetted with a drop of potassium rubber which had swollen overnight in 10 cc. of chloroform iodide solution to prevent escape of iodine and the flasks or carbon tetrachloride, that practically all of the rubber placed in ice water for 2 hours. A blank determination was coagulated. This two-phase condition made it im- is also prepared a t the same time. At the end of this period possible for complete reaction to take place, thus undoubtedly 25 cc. of 15 per cent potassium iodide and 50 cc. of distilled accounting for the low results. When larger amounts of water are added. The iodine liberated is then titrated with the chloroform or carbon tetrachloride (up t o 100 cc.) were 0.1 N sodium thiosulfate.1° Before the brownish color used, the precipitation was largely prevented and the results of iodine has disappeared 5 cc. of 5 per cent soluble starch solution are added as an indicator. Further addition of 1 Received December 13, 1926. The application of this method t o vulcanized rubber will be described the thiosulfate solution changes the deep blue to a brown in a later communication. and then to a yellow. At this point the solution is shaken a Gummi-Ztg., 26, 1879 (1912).
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I b i d . , 27, 9 (1913). I b i d . , 27, 1342 (1913). THISJ O U R N A L , la, 673 (1920). J . ~ m Chem. . SOL., a i , 1084 (1899). THIS JOL'RXAL, IS, 1031 (1921).
g The directions given by Fryer and Weston, "Oils, Fats, and Waxes," Vol. XI, p. 93, are recommended for the preparation of the Wijs reagent. 10 The conditions recommended for standardization of the thiosulfate solution are given by Popoff and Whitman. J. A m . Chcm. SOC.,47, 2259 (1925).
