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Double bromide of copper and ammonia in photography
Feb., 1889. ]
Chemical Sect~bn.
135
" I t is no exaggeration to say that the surface of the h e a p was for the g r e a t e r part covered with white, sparkling sal ammoniac, as if with snow, and, at one time, a ton at least of that salt m i g h t h a v e b e e n collected. In some places there were large cakes of it from a n inch to an inch a n d a-half thick." On digging into the h e a p after the fire was extinguished~ an a b u n d a n c e of sodium sulphate was found, b u t scarcely a n y sodium chlorkle. Following the advice of Prof. Dittmar, the author, tried the following experiments : A sample of similar ashes, d r e n c h e d with salt water, was b u r n e d in a C o r n i s h assay furnace with a supply of steam, SO.o, a n d a limited a m o u n t of air; resulting in the profuse production of NH~CI. No NH4CI was formed if e i t h e r the salt, SOs, or steam was omitted. Again, the nitrogenous substance was mixed with salt a n d iron pyrites, a n d m a d e into a little brick with clay (free from N). This was then heated in a porcelain tube, a n d steam a n d air together passed through it. The following are some of the results obtained : P a ~ d s NIt4CI P e r Tan. Black's: Slamanan coal, . . . Clyde Company's Ell coal . . . Clyde Company's Jewel coal, Coal cinders (coke) . . . . . .
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129"6 loz'2 z38"8 96-8
Experiments on the large scale were then tried with the spent shale from a mineral oil works, in a small kiln, also with coal in the furnaces of steam boilers, usingfrom five hundredweights to five tons of coal in the various tests, a n d in all cases a large yield in sal a m m o n i a c was obtained. T h e author quotes several authorities, showing that the production of a m m o n i u m chloride in b u r n i n g coal mines h a d been observed more t h a n half a century ago. It was in I884 that he m a d e the observations a b o v e described, but it does not appear from this paper, that a n y systematic application on an industrial scale h a s since b e e n made. P. D O U B L E B R O M I D E O F C O P P E R AND A M M O N I A I N P H O T O G R A P H Y .
L.L.
-de K o n i n c k (Zeitsch. [. an~eevand/e Chemie, I~*¢, 5o7).--Bromide of copper is sometimes applied for correcting over-exposed plates. It is, however, not easily prepared, a n d the commercial salt is often insoluble a n d has not the desired effect. T h e author, therefore, r e c o m m e n d s in its stead the double salt of cupric bromide a n d a m m o n i u m bromide, which is easily obtained in t h e following m a n n e r : A weighed quantity of copper fragments are introduced into a glasss t o p p e r e d bottle a n d covered with about twice their weight of water. Bromine ~s then added by degrees u n d e r frequent shaking, until all copper is dissolved as well as a n y white cuprous bromide which first forms, a n d b r o m i n e is present in small excess. Occasional cooling is advisable in order to p r e v e n t loss of bromine. T h e d a r k red solution is transferred to a porcelain dish a n d heated until the small ,excess of bromine is evaporated. To the r e m a i n i n g solution of cupric bro-
136
£Ttemical
Section.
CJ. F. I.,
mide a corresponding quantity of a m m o n i u m bromide is now a d d e d in t h e relation of 2 m01. NH4Br to mol. Cu, i. e., 195' 5 A m B r for 63' 3 Cu or 309 for too. After filtration the solution is evaporated to crystallize. T h e crystals are emerald green a n d well formed. T h e concentrated solution of this salt is wine red, the dilute like that of most copper salts, faint bluish green. A solution of ! : I,OOO of this double salt acts with great energy upon photographic silver ~pictures, a n over-exposed picture disappearing within a few moments. O.L. FILTRATION AND PURIFICATION OF COLLOID PRECIPITATES BY DIFFU-
SlOr~. E. Bauer (Chemiker-Zeilung, pose a funnel, the lower part of which paper filter reaches down into a body a beaker. By repeated c h a n g i n g the latter is finally completely washed.
I888, 789) r e c o m m e n d s for this purhas been cut off, so t h a t the apex of the of water (or other solvent) contained in water a n d covering the precipitate the O.L.
A NEW ALKALI PROCESS.--By W. W. Staveley (.[our. Soc. Chem., Ind., 7~ 8o7). During the last h a l f century m a n y attempts h a v e b e e n m a d e to decompose sulphate of sodium by m e a n s of slaked lime. E v e n in very dilute solutions a n d u n d e r a h i g h pressure, however, only a small proportion of the sodium sulphate can be So decomposed ; the reason b e i n g the comparatively great solubility of sulphate of lime, in connection with the sparing solubility of calcium hydrate. T h e author finds, however, that by the addition of cresol (CTH80 ; one of the phenols existing in oils from coal) about ninetyfive per cent. of the sodium sulphate is decomposed. Any of the phenoloids may be used, those distilling between I9 °0 a n d 250 ° C., however, b e i n g most suitable. As a practical illustration of the process, eleven h u n d r e d w e i g h t s of quick-lime are slaked a n d sufficient water a d d e d to m a k e a volume of, say, 4o0 gallons. W h e n cold, about 43 ° gallons of distilled phenoloids are added, a n d the mixture gradually run into, say, 900 gallons of a solution of ninety-five per cent. sodium sulphate, containing about t w e n t y - n i n e a n d three-fourths hundredweights of the latter. T h e mixed solutions are now agitated for several hours, at a temperature of 3o ° to 4 °0 C. About ninetyfive per cent. of the Na2SO4 has now been decomposed, with the formation of thirty-two a n d one-half h u n d r e d w e i g h t s of CaSO4, 2H20. T h e latter is allowed to settle a n d the solution of sodium phenolates run off, the calcium sulphate b e i n g washed on a filter. T h e sodium p h e n o l a t e solution is now treated with c a r b o n dioxide (from furnace fires or from lime-kiln); t h e phenoloids thereupon are liberated a n d separate as a n oily fluid, floating on the surface of the sodium c a r b o n a t e solution. T h e y can now be used over again for decomposing a new lot of Na2S04, as before. T h e Na~CO3 solution still contains about one per cent. of its b u l k of phenoloids, and, to p r e v e n t their being carried off with the steam on evaporation, a little caustic soda is added. T h e Na2CO.~ is then, after evaporation, separated as " fished salts," in the usual way, the phenoloids r e m a i n i n g in the red liquor (or r a t h e r in w h a t would correspond to the red liquor, as in this case, there are no sulphides present), a n d are, of course, united with the m a i n quantity
Chemical Sect~bn.
135
" I t is no exaggeration to say that the surface of the h e a p was for the g r e a t e r part covered with white, sparkling sal ammoniac, as if with snow, and, at one time, a ton at least of that salt m i g h t h a v e b e e n collected. In some places there were large cakes of it from a n inch to an inch a n d a-half thick." On digging into the h e a p after the fire was extinguished~ an a b u n d a n c e of sodium sulphate was found, b u t scarcely a n y sodium chlorkle. Following the advice of Prof. Dittmar, the author, tried the following experiments : A sample of similar ashes, d r e n c h e d with salt water, was b u r n e d in a C o r n i s h assay furnace with a supply of steam, SO.o, a n d a limited a m o u n t of air; resulting in the profuse production of NH~CI. No NH4CI was formed if e i t h e r the salt, SOs, or steam was omitted. Again, the nitrogenous substance was mixed with salt a n d iron pyrites, a n d m a d e into a little brick with clay (free from N). This was then heated in a porcelain tube, a n d steam a n d air together passed through it. The following are some of the results obtained : P a ~ d s NIt4CI P e r Tan. Black's: Slamanan coal, . . . Clyde Company's Ell coal . . . Clyde Company's Jewel coal, Coal cinders (coke) . . . . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
129"6 loz'2 z38"8 96-8
Experiments on the large scale were then tried with the spent shale from a mineral oil works, in a small kiln, also with coal in the furnaces of steam boilers, usingfrom five hundredweights to five tons of coal in the various tests, a n d in all cases a large yield in sal a m m o n i a c was obtained. T h e author quotes several authorities, showing that the production of a m m o n i u m chloride in b u r n i n g coal mines h a d been observed more t h a n half a century ago. It was in I884 that he m a d e the observations a b o v e described, but it does not appear from this paper, that a n y systematic application on an industrial scale h a s since b e e n made. P. D O U B L E B R O M I D E O F C O P P E R AND A M M O N I A I N P H O T O G R A P H Y .
L.L.
-de K o n i n c k (Zeitsch. [. an~eevand/e Chemie, I~*¢, 5o7).--Bromide of copper is sometimes applied for correcting over-exposed plates. It is, however, not easily prepared, a n d the commercial salt is often insoluble a n d has not the desired effect. T h e author, therefore, r e c o m m e n d s in its stead the double salt of cupric bromide a n d a m m o n i u m bromide, which is easily obtained in t h e following m a n n e r : A weighed quantity of copper fragments are introduced into a glasss t o p p e r e d bottle a n d covered with about twice their weight of water. Bromine ~s then added by degrees u n d e r frequent shaking, until all copper is dissolved as well as a n y white cuprous bromide which first forms, a n d b r o m i n e is present in small excess. Occasional cooling is advisable in order to p r e v e n t loss of bromine. T h e d a r k red solution is transferred to a porcelain dish a n d heated until the small ,excess of bromine is evaporated. To the r e m a i n i n g solution of cupric bro-
136
£Ttemical
Section.
CJ. F. I.,
mide a corresponding quantity of a m m o n i u m bromide is now a d d e d in t h e relation of 2 m01. NH4Br to mol. Cu, i. e., 195' 5 A m B r for 63' 3 Cu or 309 for too. After filtration the solution is evaporated to crystallize. T h e crystals are emerald green a n d well formed. T h e concentrated solution of this salt is wine red, the dilute like that of most copper salts, faint bluish green. A solution of ! : I,OOO of this double salt acts with great energy upon photographic silver ~pictures, a n over-exposed picture disappearing within a few moments. O.L. FILTRATION AND PURIFICATION OF COLLOID PRECIPITATES BY DIFFU-
SlOr~. E. Bauer (Chemiker-Zeilung, pose a funnel, the lower part of which paper filter reaches down into a body a beaker. By repeated c h a n g i n g the latter is finally completely washed.
I888, 789) r e c o m m e n d s for this purhas been cut off, so t h a t the apex of the of water (or other solvent) contained in water a n d covering the precipitate the O.L.
A NEW ALKALI PROCESS.--By W. W. Staveley (.[our. Soc. Chem., Ind., 7~ 8o7). During the last h a l f century m a n y attempts h a v e b e e n m a d e to decompose sulphate of sodium by m e a n s of slaked lime. E v e n in very dilute solutions a n d u n d e r a h i g h pressure, however, only a small proportion of the sodium sulphate can be So decomposed ; the reason b e i n g the comparatively great solubility of sulphate of lime, in connection with the sparing solubility of calcium hydrate. T h e author finds, however, that by the addition of cresol (CTH80 ; one of the phenols existing in oils from coal) about ninetyfive per cent. of the sodium sulphate is decomposed. Any of the phenoloids may be used, those distilling between I9 °0 a n d 250 ° C., however, b e i n g most suitable. As a practical illustration of the process, eleven h u n d r e d w e i g h t s of quick-lime are slaked a n d sufficient water a d d e d to m a k e a volume of, say, 4o0 gallons. W h e n cold, about 43 ° gallons of distilled phenoloids are added, a n d the mixture gradually run into, say, 900 gallons of a solution of ninety-five per cent. sodium sulphate, containing about t w e n t y - n i n e a n d three-fourths hundredweights of the latter. T h e mixed solutions are now agitated for several hours, at a temperature of 3o ° to 4 °0 C. About ninetyfive per cent. of the Na2SO4 has now been decomposed, with the formation of thirty-two a n d one-half h u n d r e d w e i g h t s of CaSO4, 2H20. T h e latter is allowed to settle a n d the solution of sodium phenolates run off, the calcium sulphate b e i n g washed on a filter. T h e sodium p h e n o l a t e solution is now treated with c a r b o n dioxide (from furnace fires or from lime-kiln); t h e phenoloids thereupon are liberated a n d separate as a n oily fluid, floating on the surface of the sodium c a r b o n a t e solution. T h e y can now be used over again for decomposing a new lot of Na2S04, as before. T h e Na~CO3 solution still contains about one per cent. of its b u l k of phenoloids, and, to p r e v e n t their being carried off with the steam on evaporation, a little caustic soda is added. T h e Na2CO.~ is then, after evaporation, separated as " fished salts," in the usual way, the phenoloids r e m a i n i n g in the red liquor (or r a t h e r in w h a t would correspond to the red liquor, as in this case, there are no sulphides present), a n d are, of course, united with the m a i n quantity