65
V O L U M E 1 9 , NO. 1, J A N U A R Y 1 9 4 7 Extraction of Gallium Chloride. Add 8 ml. of ether t o tlic separatory funnel and shake for 20 or 30 seconds with the usual precautions. When the layers have separated, drain the aqueous phase into another separatory funnel (rinsed with 1 t o 1 hydrochloric acid) and shake Tvith 5 ml. of ether. Draw off and discard the acid layer and combine the second et,her extract Tvith the first, rinsing the funnel with 1 ml. of et,her. Separate any smnll amount of aqueous solution present and shake the ether vigorously for 10 seconds with 1 ml. of 1 t o 1 hydrochloric acid. Drain off the a ueous layer as sharply as possible and shake the ethci, again wi% another 1-ml. portion of 1 t o 1 hydrochloric acid. Discard the hydrochloric acid washings. After the second portion of acid has been separated, add a few drops of 1 to 1 hydrochloric acid t o the funnel and draw it off without shaking t o rinst. out the stem of the funnel. Run the washed ether into a 50-ml. beaker containing 0.5 mi. of sodium chloride solution and rinse the funnel with 1 or 2 ml. of ether. Cover the beaker with a watch glass and evaporate the ether a t a low temperature. Remove the cover glass and allow all the water t o evaporate; the walls of the beaker must he dr Cool and add 2.00 ml. of 0.200 h' hydrochloric acid to the d , residue. With the aid of a stirring rod dist,ribute the acid ovet' the lower walls of the beaker. When the residue has dissolved. transfer tht. solution t o a flat-bottomed glass-stoppered tuhe and wahh the beuker and cover glass with small portions of \vatel, totaling about 3 ml. .idd 1 ml. of hydroxylamine hydrochloride solution, mix, and then add 6.0 ml. of potassium hydrogen pht,halatta solution. After mixing, allow the solution t o stand a t room temperature for 20 minutes. At the same time. prepare :L inomparison solution of the same composition (or if preferred a wries of st:intlarcls) and dilute t o the samc volume ns the sample .wlution. Fluorometric Comparison. To .;ample and comparison ;iilritions ndd 0.2-3 ml. of 8-hydroxyquinoline solution, mix by
inversion, and then add 2.0 ml. of chloroform. Shake t'he sample tube vigorously for a t least 30 seconds, allow the chloroform t o settle, and note the intensity of the ihorescence of the latter when the tube is held vertically above a n ultraviolet source in a dark room. The strength of the fluorescence serves as a guide for the initial amount of gallium t o be added to the standard tube. .ifter each addition of standard gallium solution t o the comparison tube shake well for 30 srconds. When the fluor&wnce of the chloroform in the comparison tube is almost as strong as that in the sample tube, shake the latter for 0.5 to 1 minute, and after rarh addition of gallium t o the comparison solution shake both tubw for about) 0.5 minute. When both chloroform layers sho\v the same fluorescence intensity shake for 1 minute t o he certain that distribution equilibrium has been reached and again cornpire. It is permissihle t o make the final :tdjustment by adding a small quantity of gallium to the sample solution if necessary. If the fluorescence appears too strong for good comparison, more chloroform may be added t o each tube. R u n a blank through the entire procedure. See tht, abovr cliscussion for thr :rpplication of a corrrction factor. LITERATURE CITED
(1) Goldschmidt,
I-.XI., S k r i j t e r
S o r s k e Virlar'ak.-Aknd. i Oslo, I . .Ifat. S a t u r . Klasse, S o . 4, p. 86 (1937). (2) Grahanie, D. C., and Seahorg, G. T., .I. d m . C'hern. Soc.. 60,
2524 (1938)
(3) Riendcker, G., in Fresenius and Jailtier, "Handbuch der analytischen Chemie", Part 111, 5-01. 111, p. 554. Berlin, Julius
Springer. 1942. (4) Sandell, E. B., IND.Eno. CHEM...%SAL. ED.,13, 844 (1941). (5) Swift, E. H., J . Am. ('hem. SOC., 46, 23% (1924). (6) TVada, I.. and Ishii, R..Sci. Papers Inst. Tokj/o. 34, 787 (1!1: \vith fu5eti p i i t a 4 u i i i hydi~~ixitle ot' ~ ~ I I I ~ S ~ ~ I I I ~ I ~ U S pentoxide ( 2 ) . Ai inore bei,iou:: difficulty is the slo\viies9 of thcs reaction in moit cases, although thip can he overcome b y the use of rntalysts ( 1 , .5). i L K O X Y \IERCURIAL XIETIIOD
Satisfactory results were not obtained xhen glycerol was used as the alcohol. The rate of absorption \vas increased by using hydrogen peroxide a.: a catalyst, but some oxygen was librrated a t the same time. 'Although surcess might have been achieved \vith other catalyst
