ON T H E A C T I O S OF G6" S U L P H U R I C ACID ON HYDROCIIISOX AXD THE VALUE OF THE RESULTI N G SULI'IIO ACID -1s h D E V E L O P E R FOR GELATINO-BIEO .\I IDE PLA'L'ES. 131. JAJIES li. STEDBIXS, JR.
PRELIJIIXAHY NOTICE. Since tlic introductioll of tho dry plate in photography many substances littvc been proposed as developers, b n t the only practical survivors of the substances t h u s proposed are pyrogallic acid, ferrous oxalate, hydrochinon, and more recently eikonogcn, or t h e sodium salt of amido-,3-naplitliolmonosulpho acid. Having a t one time had occasion to employ hydrochinon as a developer, I was struck with tho beautiful qualities of the plates developed by its means, but, nlthough hydrochinon is per' se 15 most excellent developer, it has, neve~thelres,sevcral drawbacks, among which are its limited solubility in wiiter. and it mas this very question of solubility mliich started me upon the present investigation. It seemed t h a t if hydrochinon could be converted into a mono-eulpho acid, t h a t its solubility would be very inaterially increased, and if t h i s could be accomplished without in any wtly affecting its reduci n g qualities for t h e haloid salts of silver, a very material improvement would be obtained. Finding only very meagre information in the literature upon this subject the following experiments were made.
EXPERIJIEST 1. 20 grams of 66" siilpliuric nciil were mixed with 10 grams of hydrochinon, and then heated under constiin t stirring upon tlie steam bsth, Lintil the hydrochinon was all dissolved. T h e stirring was kept u p for a few minutes lo!iger, when saddenly t h e whole contents of the beaker solidified to a cake of sm;ill straw colored needles.
156
A C T I O N OF
66" SI'LI'HURIC A C I n OK HYDROCHIXOX, ETC.
T h e cake was broken u p anddissolved in cold water,in wliich i t is very soluble, then converted into its lime salt by neutralizing the acid solution with calcium carbonate. T h e precipitate of calcium sulphate W:LS filtered off arid the filtrate of tlie l i m e salt placed upon the steam bath for concentrtLtion. After a short. exposure t o t h e air the solutiou began t o darken, sliowing tliat oxidation wrts taking place. Concentratioii by this means had tlicreforc to be abandoned. The solution was tlicn placcd under the air p u m p oversnlphui.icacid,liopitigtliat by this riieitns it may he concentrated without spoiling, l,nt even in this case oxidation kel)t dowly taki n g placc. I t was therefore decided to treat the mixtui,c with an excess of sodium sulphite and then concentrate in vacuo over sulphuric acid. On adding the sodium sulpliite calcium sulphate was precipitated carryiiig considerable of t h e coloring matter with it. T'lie precipitate was filtered off, arid the filtrate containing t h e sulpho acid of Iiydrochinon was placed under the bell jar of t h e air p u m p owi*sulphuric :tcid, to concentratc1.. b n t owing t o an accident, the contents of tlic beaker wcrc spilled, and therefore the experiment liad to be rcperttetl.
.ExPE K I 11E ST 2 . 10 grams of Iiydrocliino~~ were treated as before with 20 grams GG" sulphuric: acid. After the reaction the mixture was dissolved
in water, heated upon tliewater bath, and neutralized with barium e11r boil a t e. The barium snlphate was filtered off, and tlie filtrate containing the barium s;t!t of the sulplio.scid was concentrated in vacuo over snlphuric w i d . T h e barium salt t h u s obtained crystallized much more readily tliitn the calcium salt and the solution of the same in water does not appear to be ss re:tdily oxidizable as the former when exposed to the air. I t crystallizes from its aqueous solution i n white, warty concretions of star-grouped crystals (needles). A samlylc of tlic ~ J O V Cbarium salt obtaiiied by rnl'idly boiling dowii a portion of its aqueons soliitioii to dryness and tlicn fiirtli:'r d r j i n g over sulplinric acid g t v e the following results :
Wder of' Crystnllizntiu~z, 0.2310 g m . substancc lost 0.0081 grm. II,O equivaleiit to watci. 8.88 per ccnt., or 1 mol. water of ciytallization.
ACTIOS OF 66" SULPHURIC AOID O N H T D R O C H I N O S , ETC. 157
Bn. Esiiinntiuii. 0.2810 grm. sub. gaveO.llG grm. Ba SO,
Equivalent to Ba- - - - - - - - - - - - - - - - - - - - - -24:2G per cent. C( Equivalent to Ba. in anhydrous Ealt- - - - -24.98 On now attempting to calculate t h e molecular weight .of the barium salt from tlie amount of barium sulphate formed, we get t h e following : 0.2'729 anhydrous salt gave 0.116 gram. Ba.SO,. .116: 233 (BsSO,) 1: 0.2720 : x ; x=548.1
Tho least molecular weight of the salt, carrying one atom of barium, is therefore 548.1. One atom of barium might belong, however, to a substauce containing either one or two sulpho-groups ; bnt, the theoreticd molecular weight of barium hydrochinon disulphonate is 40G, whereas the theory for barium hydrochinon moilosulphonate is 515, (calcnlated from t h e forrnuls p.C, €I,(--SO,
z13a,) and O \,O ' H 13 consequently the former is cxclnded. Therefore tlie substance analysed is beyond mnch doubt t h e bnrinm salt of a hydrochinon mono-sul pho aci cl. dil calculating t h c molecular weight from t h e salt coiitainiiig water of crystallization we get : 0.116 : 233 :: 0.?81 : x ; x=564. T h e theoretical molecular weight of t h e hydrated salt, or rather salt coiltaining natcr of cr~stdliziitioil,is 533. The theoretical amoniit of barium called for in the anhydrous salt is 2 G . G per cent. 'I'lic theoretical amount of barium in the hydrated salt is 25.7 per ccii t. T h e amount of water of crystallization found is 2 3 8 per cent. ; therefoi e, ?.YS+IS:: 0.16 mol. H,O. T h a t is to say, that 100 p:irts of bitrium salt coiitaiii 0.1G mol. H,O of crystallization ; therefore 548 parts of barium salt mill
(
)
158
h C T I O S OF
66" SUI.I'HLHIC:
A C I U OX I I Y U R O C H I S O S , ETC.
coiitiLin 100 : 0.1Ci=54S : 4 ; 4=0.8; mol. H20,o r Iii round numbers 1 mol. Ift(.). \-e hnvc therefore found : Bai,iurn. . . . . . . . . . . . . . . . . 24.2Cj pel' cent. a , , WEtterof crgstallizatioii . . . - -,hh . . . . . . . ,=)(i4 No! ec ti 1ii w cig 11t ....... IYIiereas theory ctills for I3nritini.. . . . . . . . . . . . . . . . . . . . . . . . . 2 5 . 7 per cent. \Vat e r . . . . . . . . . . . . . . . . . .. 3.40 Mol. weight.. . . . . . . . . . . . . . . . . . . . . . . . 5:33 Tlic formtits of tlie bnrinrn salt is tliei.cfoi.c, witliout mucli donbt : :i
~
15
/OH
1'.
c,I:,(----so, \OH
1'.
/ OH
c, LI3Ih+HzO
/
\ OH T h e bnrinm salt is i.c.adiiy soluble in cold water arid dilute alcohol nnd insoluble i i i strong alcoliol. I t crystitllizes from dilute alcohol i i i white, sis-sided prisms. 0 1 1 acldiiig ferric chloride to ita aqueons solution. i~ momenttiry deep blue coloration is obtained. which, almost immecliiitel~,c1:angrs into a dirty yellom color. 1'OT.iSSIL-)I
S.'LLT.
This salt was obtnined from t h e bizrinni salt, by decomposing t h e latter with the tlieoretical amount of potassium carbonate. On rapidly concentrnting t h e nqneous solution of t h e same, o u t of cont a c t witli t h e air, as mucli as possible, i t is obtained in t h e shape of little, pellowish white Iieedles. Bctter results, however, are obtained by ndding three or f o u r volumcs of :ilcoliol to t h e concentrated aciiieous solnt~ioii,nncl then :illowing t h e mixtnre t o evnporate under t h e I)cll jar of i i n air 1)iirnp. I t is readily soluble i n i v at e r .
T h e frecacid niny be obttiined from tlie barium salt by acciirately decomposiiig tlie latter with dilutc snlpliuric acid, filtering
off t h e HaSO,, sliakiiig u p tlie filtrate with ether! and then clistilling off tlie lHttcraiid:iIIo\\~iii~ to cryst;illlze. -1simpler metllod. ntid o i i ~tli:it works very well, is to placc the cake resulting froiii the action of 13,SO, upoii t h e hyc!rocl~inon, npon porous tiles, till t h e greiiter part of tile esccss of siilpliuric acid Iiiis been absorbed. Tlieti press t h e INRSS between filter paper iintil ne;irly every trace of H,SO, has been removecl. 'I'he mass thus obtained is dissolved in as little alcoliol RS possible, and set aside to crystallize under the air pump. T h e free w i d is thus obtained in long, wcll defined Lromnish, transparent, rhombic prisms (some of tlie crystals were over 1 cm. long), containing alcohol of crystallizntion. When exposed over sulphuric acid i t effloresces, giviiig off a part, or all, of its alcoliol of crystnllizR t '1011. 0.2155 grm. snb. over H,SO, lost. .()OS; grm. alcoliol=753 per cent. On now heating to 1?O3 C . the sitid free acid lost ,004 grm. more of alcohol. It will therefore be seen that the larger part of the nlcohol of crystnl1iz:ition is lost over II,SO,. T h e total amount of alcohol lost id t!icrefore .00d;f.004=.01?7 gram.=10.9 per cent. This equals 0.43 molecule, or in isouiitl numbers oiie-half molecule alcohol of crystti1 li zat i on. Theory for C,[-I,(H SO,) (OH),. One-1i:ilf C,H,O ciills for ~ 1 who1 10.7 per cent. It begins to fiise :it 9s" c. m d is completely fused a t 104' c. (uncot*rected). Dissolves readily i n mater and nlcoliol. R E D V C I K G A C T I O S 1-POS T H E H A L O I D SALTS O F S I L r E R .
I t was thougilt t h a t tlic best wiiy td test this question would be t o submit some exposed gelatine dry plates t!, the action of tlie hydrochinoti mono-sulplio acid. For this purpose ii p i ~ l i m i n a r y test was mad$, using an Eatman I:iiiterii slide plitte, and a solution of t h e barium salt of the hjdrocliiiion sulplio acid, made slightly alkaline with sodium cwbonate. A positive of very fair quality was t.lius obtained, tho tone of color being redclisli brown. I t developed u p very slowly, however, but i t is especteil t h a t better results will be obtained when nsitig a developer of definite compositioi~. I n conclusion I would state, t h a t I hope soon to complete experiments upun this subject, and mill tlieii submit 8ncI1 further results as I may havc obtaiited.
