T H E J 0 c' R &V.4L 0 F I .V D 1.ST RI IL .1 .V D E S G I
OCt., 1913
~
f o r anaesthetic purposes should comply with t h e following requirements : I . BoiZiiLg Point.-Ethyl chloride should possess a boiling point of + I Z . j oC . 2. Odor.-On allowing 3 0 cc. of ethyl chloride t o evaporate from a filter paper l z l 2 cm. in diameter. n o foreign or unpleasant odor. especially a garlic odor (indicating phosphorus compounds). should be ap,parent either during or subsequent t o evaporation. .j. Kesidzie.-When 6 0 cc. of ethyl chloride are allowed t o evaporate in a platinum dish a t room temperature. there should be left no weighable residue. 1. . ~ / ~ o h o-When / . ~ ~ I O cc. of ethyl chloride are agit a t e d with I O cc. of distilled water, both of which are a t about IO' C.. in a glass stoppered t u b e , and t h e s u p e r n a t a n t layer of ethyl chloride is allowed t o evaporate spontaneously froni t h e opened t u b e a t 1'o 0i n t e nip era t 11re a n (1 t hen L3 d r o p s of pot a s si 11m tiichroniate T. S. a r e a d d e d t o t h e remaining w a t e r , followed b y .; drops of dilute sulfuric acid, a n d the misture is t h e n Iioiled. no odor of acetaldehyde should be apparent a n d no greenish or bluish color should be produced in t h e liquid. j . Hydrochloric 1 : rid iiiid Metallic ('hlorides.-- On dissolving I O c r . of ethyl chloride in I O cc. of 9 j per a n d t h e n adding .idrops of silver cent alcohol U.S. P., nitrate T. S.,no turbidity. even faint, should result, a n d no precipitate should form. A simple combination test for t h e purity of ethyl rhloritle consists i n attaching a .30 cc. ethyl chloride container t o a glass t uhe vial containing .i,j cc. of water kept a t 40' C . sloiv stream of ethyl chloritic is passed through the water until the container is emptied. and t h e n I O cc. of t h e water are tested with litmus p a p e r , to which it should i m p a r t n o acid reaction: I O cc. with silver nitrate T . S.. as in f c s ! ;. a b o v e ; and I O cc. are finally tested for alcohol as in Icst ,; above. 'THE P U R I T Y U E T H E L I ' H Y L C H L O K I D E S O S 'THE A I I E R I C A S XIA R K E T
Recently the authors examined the products of f o u r American manufacturers, in order t o ascertain whether t h e grades in use complied with the requirements of t h e various pharmacopoeias above cited. T h e results are presented in Table I . It, will be seen t h a t all t h e samples examined were of official grade. American manufacturers appear t o t a k e t h e necessary simple precautions t o guard against t h e presence of organic impurities. Cur,r,i%~
U P TUE
CITY OF
~ ' E W YORE
A RAPID VOLUMETRIC METHOD FOR DETERMINING O- m- AND @-CRESOLS, THYMOL AND PHENOL B y L.
v.
K E D M A N .A . J.
\ ~ E I T HAND
F. P.
BROCK
Received July 14, 191.1
This method determines b y one titration rapidly a n d accurately: A . Ortho-, meta- and para-cresols or phenol. B. T h e meta-cresol in t h e presence of 0 - and p-cresol. C. Phenol in t h e presence of 0 - and p-cresol.
E E RI &VG C H .!i M I S TR Y
D. T h e meta-cresol, t h e phenol a n d the sum of t h e a n d p-cresols in a n y mixture of thesc compounds. Three methods have been proposed for determining t h e cresols scparntely : ( I ) gravimetric,' neighing the 0 r t h o - a nd p a r a - c r e s 01 a s t 11e d i bi.0 I11 - c resol - h 1'0 IT1 i t r , tlic meta-crcsol as tribroni-crcsol-1,roinidc; ( 2 ) volw metric,' h y Koppeschaar's solution. titrating hack t h e unabsorbed bromine; ( 3 ) volunietric. hy using a solu tion of iodine2 in sodium acetate and titrating back t h e unabsorbed iodine with thiosulfate. This latter method does not serve for t h e quantitative determination of m-cresol. X special method has been tle\*isetl for tleterniining rn-cresol:3'4in t h e presence of ortho- and para-cresol, b y weighing the m-cresol as trinitro-m-cresol. T h e 0 - a n d p-cresol arc osidizccl away h y strong nitric acid a n d trinitro-phenol is solublc if prescnt in siiinll amounts. i. r . . lip t o I O per cent. The method. therefore, is reliable in the presenve of 0- : i i i d p-cresol a n d less t h a n I O per cent of phenol. H . Ilitz.' h a s given the following equations whereby the m-cresol present in a mixture consisting only of the three o-cresols may be determined z+?:=(I (1) 3Br.z 2Br.y -. . . __ .. 0-
~
+
108.064
= b
2)
meta-cresol. and p-cresol. = V t . of misture of cresols t a k e n . h = K t . of Br disappearing. Br = 7 9 . 9 7 grams. I he s a m e equations will apply t o a mixture of the 0 - ur p-cresols :inti phenol. T h e equation ( 2 ) is modified for t h e lormula weight of the phenol6 :is follows: ~3Br.n: 2BT.Y = (3) 94.048 + 108064 Y = the amount of phenol in the mixture taken. Siegfried and Zimmerniann7 have criticized H . Ditz a n d Cedivotla's method and have shown t h a t \,ariablc results froni 2 - 2 0 per cent a r e ohtaiiied 114' ljrominating the cresols in :in acid bromine solution. Their method varies from t h a t of Koppeschaar's for determining phenol. only in t h e fact t h a t one hour's time is allowed after the K I is added before the thiosulfate is run into t h e solution. F. Russig and G.F o r t m a n n 4 have also criticized Ditz and Cedivoda's method adl-ersely. Ditz replied4 t o their objections and H. Diiz rind F . Bardachg have published results a t varianc:c i v i t h Russig and Xortmann's conclusions. Recently Pence]" has shown t h a t Koppeschaar's solution in a n acid menstruum will determine quanti-
.x
=
,
== 0 -
(I
,
