Nov., 1918
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E i M I S T R Y
IMPORTS OF MISCELLANEOUS PRODUCTS (Concluded) 1914 1916
ARTICLES
Paper: $ 960,346 81 ,903,503 $1 Printing.. 288 394 3 12,634 Canada. 895 73,295 Germanv. 116,675 30,133 Norway.. 224.044 110.898 Sweden 996,095 439.567 United Kingdom.. 213,654 45,235 United S t a t e s . . 306,765 1,127,320 Wrapping. 2,540 288,365 Canada. 35,117 209 Germany.. 57,070 177,175 Norwav.. ..................... 110,898 348,101 Sweden 288,282 80,847 United Kingdom.. 5,290 79,752 United States. 240,177 292,569 Photographic material'. ............. 122 15,418 Germany. 132,491 168,434 United Kingdom.
....................... ...................... ..................... ..................... ....................... ............. ............... ...................... ...................... .................... ....................... ............. .................
~
.......................
United States. ........... Extracts and powders.. . . . . .
.
United States.. Sugar, molasses, etc.
,754,617 365,810 1 i i :ibo 382,346 606,142 225,095 840,634 168,113
.....
50,514 251,866 278,627 50,646 295,353
87,845
120,383
liS:849 108,396
184,467 150,862 7.539 28,455 155,101 102,757 39,905 11,996 11,315 428
172,002 77,013 30,211 63,834 263,000 174,284 85,203 26,333 25,895 389
130,208 82,293 23,924 19,432 207,011 151,597 50,495 21,408 21,198 107
58,899 54,627 312,750 312,493 88 3,650 1,197 1,314,889 588,384 586,170 7.898 - ,--
69,012 67,771 107,443 106,937 165 3,158 1,523 245,495 14,999 186,056
111,930 100,664 27,968 24,990 1,645 808 545 821,339 43,608 724,052 49.843
Molasses and treacle Saccharum. ..................... Surcar ........................... Mauritius. .................... Portuguese East AErica.. United States 1 Sensitized goods not stated separately.
........ ..................
1917
~
I
3 -4 -.,523 ---
MISCELLAKEOUS MATERIALS
Zinc is t h e only item of outstanding importance in this group and it is now imported almost exclusively from t h e United States. Previous t o t h e war Germany was a serious rival. T h e extent t o which t h e various items are imported is shown in t h e following table: IMPORTS OF
MISCELLANEOUS MATERIALS
ARTICLSS 1914 1916 METALS : 5 24,747 $ 39,959 $ Copper, bar, ingot, rod.. . . . . . 36,903 Iron, pig and ingot.. . . . . . . . . . . . . . . . 20,770 Lead, bar, pig, and sheet.. . . . . . . . . . . 80,419 119,190
...
Tar and substitute
1918
134,817
192,003
23,126 56,617 58,734 188,664
17,729 340,169
14,230 227,475
20,863 105,389
86,088
137,887
142,224
( a ) Not stated separately in 1914.
ORIGINAL PAPERS EXAMINATION OF ORGANIC DEVELOPING AGENTS By H. T. CLARKE Received July 20, 1918
F r o m t h e time t h a t t h e European war c u t off t h e supply of foreign organic chemicals t o this country, t w o distinct activities have been apparent in t h e photographic developing agent trade; on t h e one hand, t h e efforts of manufacturing concerns t o produce t h e most necessary substances, like hydroquinone a n d salts of p-aminophenol, and, on t h e other, t h e less commendable manipulations of t h e purveyors of bogus and adulterated developing agents. For t h e control of both of these activities. chemists are necessary-to check t h e purity of t h e genuine products a n d expose t h e composition of t h e false. Moreover, in many cases developing agents are submitted under fancy names and it is necessary t o identify t h e substances t h e y contain. T h e work of t h e analyst t h u s falls into three classes: t h e separation a n d identification of genuine developing agents; t h e quantitative determination of such substances; a n d t h e identification of t h e materials employed for adulteration or substitution. T h e following scheme for t h e identification of t h e commoner developing agents is drawn u p t o meet t h e first; a few suggestions for quantitative work follow; b u t owing t o t h e enormous number a n d variety of adulterants, n o a t t e m p t can be made t o indicate all of t h e methods employed for their detection a n d estimation, which in a n y case are subject t o t h e methods of routine analysis.
QUALITATIVE METHODS GROUP TESTS
Taking 0 . I g. of sample: I-Insoluble in 5 cc. of cold water: p-Hydroxylphenyl glycine 11-Soluble in 5 cc. of ether: Hydroquinone Chlorohydroquinone Catechol Pyrogallol 111-Soluble in 5 cc. of alcohol: p-Aminophenol base p-Aminophenol hydrochloride 5-Amino-2-cresol hydrochloride 2,4-Diaminophenol hydrochloride p-Dimethylaminophenol oxalate IIIa-Insoluble in alcohol: p-Aminophenol sulfate 5 -Amino-n-cresol sulfate $-Methylaminophenol sulfate $-Dimethylaminophenol sulfate o-Methylaminophenol sulfate p-Phenylenediamine hydrochloride DISTINGUISHING TESTS
(A) Test aqueous solutions with litinus: Neutral or only faintly acid with Group 11; Groups I11 a n d IIIa give markedly acid solutions (with t h e exception of pure paminophenol base). Test aqueous solutions for chlorides, sulfate, oxalate, a n d other common anions. (B) Treat 0.I g. in I cc. hot water with one or two drops of I O per cent sodium carbonate solution, a n d let mixture stand a few minutes t o cool.
T H E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y Vol.
892
GROUP I. 9-Hydroxyphenylglycine-Dissolves with effervescence; very little change on standing. GROUP 11. Hydroquinone, Chlorohydroquinone, and CatecholNo effervescence; solution darkens slowly on standing. Pyrogallol-No effervescence, solution darkens rapidly on standing. GROUPS 111 AND ma-All cause effervescence except pure p-aminophenol base. Crystalline precipitates formed on cooling: Salts of p-aminophenol, 5-amino-2-cresol and o-methylaminophenol. No precipitate on cooling: Salts of 2,4-diaminophenol, p-methylaminophenol, p-dimethylaminophqnol, and p-phenylenediamine.
(C) To 0.I g. of sample in 2 cc. of water add a few drops of I O per cent ferric chloride solution. GROUP I-+Hydroxyphenylglycine gives no color reaction in the cold; odor of quinone on boiling. GROUP 11-Hydroquinone gives dark greenish precipitate of quinhydrone in the cold; strong odor of quinone on boiling. Chlorohydroquinone gives reddish brown coloration in the cold, odor resembling that of quinone on boiling. Catechol eives a green coloration with one drotl of ferric chloride; with excess a nearly black prehpitate is formed; no odor is produced on boiling. Pyrogallol gives intense reddish brown coloration in the cold; no odor on boiling. GROUPS 111 AND ma-Salts of p-aminophenol and 5-amino-2Cresol give purple colorations in the cold; odors of quinones on boiling; the purple colors are not destroyed. p-Methylaminophenol sulfate behaves similarly, except that the purple coloration is developed more slowly. Salts of p-dimethylaminophenol give no color in the cold; the solution darkens on boiling, with formation of quinone odor. With z,q-diaminophenol hydrochloride an intense red color is developed in the cold; no odor is produced on boiling. With o-methylaminophenol sulfate a dark purple color is produced, turning to red-brown on standing or more rapidly on warming. No odor is produced on boiling. With p-phenylenediamine hydrochloride a deep green color is developed, followed immediately by a dull purple; on boiling, the color changes to a dull reddish brown, and the odor of quinone is produced. I
-
(D) To 0 . I g. of sample in I cc. of water add z cc. of 5 per cent silver nitrate solution. GROUP 1-p-Hydroxyphenylglycine in suspension causes a black deposit in the cold which, on boiling, instantly becomes light haw-n, while the liquid rapidly acquires a purple color. GROUP 11-Hydroquinone gives a silky white precipitate in the cold; the odor of quinone is developed on boiling. Chlorohydroquinone scarcely reduces silver nitrate in the cold, but rapidly on boiling. Catechol slowly reduces the reagent in the cold; no characteristic color or odor developed in boiling. Pyrogallol causes instant reduction in the cold, giving a brown precipitate; no odor produced on boiling. GROUPS 111 AND I I i a S a l t s of p-aminaphenol, p-methylaminophenol and ~-amzno-2-cresol give purple colorations, with quinone-like odors on boiling. Salts of p-dimethylaminophenol give no color in the cold; on boiling, a brownish red color and the odor of quinone are developed. z,4-Diaminophenol hydrochloride yields an intense red color; no odor on boiling. 0-Methylaminophenol sulfate gives a yellowish brown color in the cold, becoming reddish brown on heating; no odor developed on boiling.
IO,
No.
II
p-Phenylenediamine hydrochloride yields in the cold a transitory pale green color, followed instantly by a deep purple; no color change and no odor on boiling. SPECIFIC TESTS
Two reactions which should be performed with every developing agent are acetylation a n d benzoylation. In acetylation the substance is mixed with about three times its weight of acetic anhydride, together, if t h e developing agent be a salt of a base, with a n equal weight of anhydrous sodium acetate, a n d t h e mixture gently boiled for a few instants over a flame. After t h e mass has cooled, about ten volumes of water are added and t h e separated solid filtered off a n d recrvstallized from alcohol or similar solvent. In benzoylation (Scliotten-Baumann process) t h e substance is mixed with about four times its weight of benzoyl chloride, a n d an excess of I O per cent caustic soda solution added, whereupon t h e mixture is VigorouslY shaken in a stoppered 'tube, cooling if necessary, and occasionally releasing a n y excess pressure by opening t h e stopper. Shaking must be continued until t h e irritating odor of t h e benzoyl chloride has disappeared. Care must be t a k e n t h a t a n excess of alkali is present a t t h e end of t h e reaction. The separated solid is then filtered off, washed with water, a n d recrystallized from acetone or other suitable solvent T h e derivatives t h u s produced possess characteristic melting points, so t h a t a n y identification can b e definitely established b y their aid. GROUP 1-#-Hydroxyphenylglycine dissolves readily in dilute sodium carbonate, sodium hydroxide, sodium sulfite, or ammonia; also in dilute mineral acids, but not in dilute acetic acid. When pure it crystallizes in colorless leaflets, melting indistinctly with decomposition above zooo. GROUP 11-The four substances described in this group all form bright yellow, water-soluble compounds with sulfurous acid (or sodium bisulfite and dilute acid). Hydroquinone crystallizes readily from water in colorless needles melting a t 169'. It boils a t 285 The vapor is almost odorless. It is insoluble in benzene. Quinhydrone, precipitated by a cold acid solutiofi of ferric chloride, or of potassium bichromate, melts at I 7 I O. Quinone, formed by the action of an excess of acid bichromate, melts a t I 16 The diacetyl derivative melts a t 123'; the dibenzoyl derivative melts a t 199'. Ch1orohydroqu:none is too soluble in water to crystallize from aqueous solution. It dissolves readily in warm benzene. It melts a t 106' and boils a t 263'. The vapor has a distinct phenolic odor. The diacetyl derivative melts a t 99'. Chloroquinone, produced by oxidizing with acid bichromate, melts a t 57'. Catechol forms feathery needles which melt a t 1 0 4 O and boil a t 245' and are extremely soluble in water. It is readily soluble in hot benzene, sparingly in cold. It possesses an odor resembling that of pyrogallol. On treatment with bromine in carbon tetrachloride solution, hydrogen bromide is evolved, and a tetrabromo derivative melting a t 192 O is produced. The diacetyl derivative melts a t 63 O ; the dibenzoyl derivative melts a t 84O. Pyrogallol is extremely soluble in water. It is slightly soluble in hot benzene, almost insoluble in cold. It melts a t 133'' and boils a t 293'. It possesses a peculiar and characteristic odor. Its aqueous solution gives a blue precipitate with ferrous
'.
'.
Nov., 1918
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
sulfate. The triacetyl derivative melts a t 161'; the tribenzoyl derivative melts a t 89'. GROUPS 111 AND m a . p-Aminophenol and Its Salts-The free base crystallizes from water in leaflets, melting with decomposition a t 184', soluble in about 100 parts of cold water. It is moderately soluble in hot alcohol, sparingly in ether. The hydrochloride crystallizes in prisms, and is sparingly soluble in concentrated hydrochloric acid. The sulfate, crystallizing in fine needles, is less solhble in cold water than the hydrochloride, but the hydrochloride is precipitated from an aqueous solution of the sulfate on adding concentrated hydrochloric acid. On adding to a cold. slightly acid solution an excess of sodium acetate and then a few drops of benzaldehyde, the pale yellow benzylidene derivative is soon precipitated, which crystallizes The diacetyl from methyl alcohol in needles melting a t 183 derivative melts a t 1 5 0 ~the ; dibenzoyl derivative melts a t 234'. 5-Amir~o-2-cresoland its salts resemble p-arninophenol and its corresponding salts very closely in solubility and chemical behavior. The free base crystallizes from water in flat needles melting with decomposition a t 176 The hydrochloride crystallizes either in needles, or, less frequently, in leaflets. The sulfate crystallizes in fine needles. On oxidation with acid bichromate it yields toluquinone melting a t 68 The benzylidene derivative is markedly less soluble than benzylidens-paminophenol in methyl alcohol, from which it crystallizes in The diacetyl derivative melts a t I03 O ; leaflets melting a t 208 on gentle hydrolysis with alkali it yields the monoacetyl derivaThe dibenzoyl derivative melts a t 194'. tive melting at 179'. z,4-Diaminophenol is met with only as the hydrochloride. The,free base is not precipitated from solution on addition of sodium carbonate ; the neutralized solution darkens very rapidly in air. The hydrochloride is sparingly soluble in concentrated hydrochloric acid. Attempts t o prepare a benzylidene derivative led to a smeary yellow product. The triacetyl derivative melts a t 180";the tribenzoyl derivative melts a t 231'. 9-Methylaminophenol is met with only as the sulfate, which crystallizes in fine needles. The free base is fairly readily soluble in cold water, but is precipitated on neutralizing a cold saturated solution of the sulfate with sodium carbonate; it melts a t 85' and is extremely soluble in ether. On allowing a solution in an excess of sodium hydroxide to stand in air, a dark color rapidly develops, accompanied by a characteristic odor not unlike that of a trace of pyridine. On adding sodium nitrite solution in slight excess to a solution acidified with sulfuric acid, the sparingly soluble nitroso derivative separates in colorless needles melting a t 1 3 6 ~ . The perfectly pure monomethyl compound yields no benzylidene derivative on treatment with sodium acetate and benzaldehyde, but technical samples are rarely entirely free from salts of p-aminophenol, which is converted by benzaldehyde into the insoluble benzylidene p-aminophenol. A good technical sample should be completely soluble in three parts of concentrated hydrochloric acid. The diacetyl derivative is insoluble in cold water and melts a t 97 '; on gentle hydrolysis by warming with dilute alkali this is converted in the monoacetyl compound (soluble in alkali The dibenzoyl and precipitated by acid) which melts a t 240'. derivative melts a t 173'. e-Dimethylaminophenol-The sulfate crystallizes in hexagonal tablets which are extremely soluble in water. The oxalate is moderately soluble in water and alcohol; it melts a t 187' to 191'. The free base is fairly readily soluble in cold water; it melts a t 75O and is extremely soluble in ether. On allowing a solution in sodium hydroxide t o stand in air, the same dark color and pyridine-like odor are developed as with the monomethyl compound. On adding sodium nitrite to a solution in dilute acid, a reddish brown coloration is formed, with evolution of gas. On adding a saturated solution of potassium ferrocyanide to a fairly concentrated solution in dilute sulfuric acid,
'.
'.
'.
'.
893
a white crystalline precipitate of the acid ferrocyanide soon separates. I t forms an acetyl derivative melting at 78", 2nd a benzoyl derivative (soluble in dilute acid) which melts a t 158', o-Methylaminophelzol-The sulfate crystallizes in stout needles which are extremely soluble in water; the free base, which is slightly soluble in cold water but readily so in hot water, crystallizes in leaflets melting at 96 '. It dissolves in alkali, forming a solution which slowly darkens to a dull green color on standing in air, giving a pyridine-like odor. but more slowly than the para compound. The free base and its sulfate are completely soluble in three parts of concentrated hydrochloric acid. On adding sodium nitrite to a solution in dilute acid, the nitrous compound is precipitated in colorless leaflets which melt with decomposition about 130' after darkening from 120' onwards (the melting point is rather indistinct and depends upon the rapidity with which the bath is heated). The derivative obtained on acetylation is a liquid which dissolves in cold water; on gentle hydrolysis by warming with dilute alkali i t yields the monoacetyl compound (soluble in alkali and precipitated by acid) which melts a t 150'. The dibenzoyl derivative melts a t 113'. p-Phenylenediamine-The hydrochloride crystallizes in leaflets which are readily solublein water. The free base, melting a t 140'~is moderately soluble in cold water and sparingly in ether. On adding to a cold dilute solution an excess of sodium acetate and then a few drops of benzaldehyde, the pale yellow dibenzylidene derivative is precipitated; this crystallizes from methyl alcohol, in which it forms a bright yellow solution, in thin leaflets, Both the diacetyl and dibenzoyl derivatives melting a t 138'. melt a t temperatures too high for convenient measurement. QUANTITATIVE METHODS
It f r e q u e n t l y h a p p e n s t h a t p h o t o g r a p h i c developers placed u p o n t h e m a r k e t consist of mixtures of developi n g a g e n t s or of i m p u r e simple s u b s t a n c e s , so t h a t it m a y b e necessary t o s e p a r a t e a n d e s t i m a t e t h e cons t i t u e n t s of a m i x t u r e or t o d e t e r m i n e t h e p u r i t y of a s a m p l e of a single s u b s t a n c e . GROUP I-No direct method for determining the purity of a sample of p-hydroxyphenylglycine is available. An ash determination should be made, and the amount of matter insoluble in dilute sodium carbonate estimated. If a sulfite be present the sulfurous acid liberated by mineral acid should be determined by the method indicated below. GROUP 11-All the substances in this group should leave no ash on ignition; if there be any, it should be estimated. Likewise, all should dissolve in water and in ether without residue, and should leave no considerable residue when the main constituent is volatilized under atmospheric or reduced pressure. The melting point forms a fairly satisfactory criterion of the purity when the sample is found to be completely soluble in ether. The proportion of hydroquinone in a sample of chlorohydroquinone may be estimated by isolating and weighing the matter insoluble in warm benzene. GROUPS 111 AND ma-Water-insoluble material and ash should be estimated; in Group I11 the amount of matter insoluble in alcohol should also be determined. The proportion of chloride, sulfate, sulfite, etc., should be determined; and in certain cases it may be well to estimate the total nitrogen by the Kjeldahl method, making certain, of course, that free ammonium salts are absent. I t is i m p o r t a n t i n all cases t o d e t e r m i n e the a m o u n t of salts of p-aminophenol or aminocresol present, b o t h i n samples consisting principally of o n e of t h e s e comp o u n d s and in s a m p l e s of m e t h y l a t e d derivatives. T h e p r o c e d u r e is as follows:
894
T H E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y Vol.
Ten grams of t h e sample are dissolved in about 150 cc. oT cold water (or, in t h e case of the free base, dilute hydrochloric acid). Heating must be avoided, since this may cause impurities t o enter into solution which do not again separate on cooling. A slight excess of sodium acetate is then added, and t o t h e cold solution about I O cc. of benzaldehyde are run in. When t h e sample contains a relatively small proportion of aminophenol, as in samples of p-methylaminophenol sulfate, t h e amount of benzaldehyde should be considerably reduced. After standing over night the mixture, which should still contain excess of benzaldehyde, is filtered by suction, t h e solid well washed with water, dried in t h e steam oven, and weighed. A Gooch crucible answers satisfactorily. The following factors are applied for expressing the result:
.................. 0.802 0.738 ........................ ............................ 0.554 ................. 00.756 ...................... .815 ......................... .O.584
As p-aminophenol hydrochloride. As p-aminophenol sulfate.. As p-aminophenol base As 5-amino-2-cresol hydrochloride. As 5-amino-2-cresol sulfate., As 5-amino-2-cresol b a s e . .
For t h e remaining substances in this group t h e simple though non-specific total nitrogen content must be determined and t h e assumption made t h a t all t h e nitrogen is in t h e form of t h e pure substance. INORGANIC RADICLEs-mThen an ash has been found and shown t o consist of a salt of an alkali metal, a weighed sample of t h e substance should be ignited in a platinum crucible and t h e residue repeatedly evaporated t o dryness and heated t o redness after adding a few drops of 2 0 per cent sulfuric acid; in this way t h e metal is completely converted into t h e sulfate. Chlorides and bromides should be determined by t h e Volhard method. Direct estimation of alkali carbonate is difficult or even impossible in some instances, and may have t o be effected b y difference. Sulfites are best estimated by distilling a n acidified solution of the sample into alkali and titrating t h e distillate against standard iodine solution, running t h e sulfite into t h e iodine. A regular Kjeldahl distillation apparatus answers well for t h e purpose. TYPICAL ANALYSES
For obvious reasons t h e sources of t h e material used for these typical analyses are not indicated; they represent a selection from a very large number performed in t h e years 1916-1918. “MQ” DEVELOPER T U B E (APRIL 1g16)-The total weight of material in t h e compartment containing t h e developing agent was 0.6276 g. This was placed on a filter and well washed with ether; the ethereal solution, on evaporation, left pure hydroquinone; t h e insoluble residue, when dried a t IOO ’, weighed 0.1241 g. a n d was found t o consist of pure $-methylaminophenol sulfate. The hydroquinone was not weighed, b u t estimated by difference. “MQ” DEVELOPER T U B E (APRIL 1916)-A similar analysis on another t u b e showed total weight 0.5713 g. ; ether-soluble material consisted of pure hydroquinone; ether-insoluble material weighed 0.I I 2 0 g. and consisted of technically pure p-aminophenol hydrochloride.
IO,
No.
11
DEVELOPING AGENT (MARCH 1g16)-The material was a light brown powder of rather moist appearance. It contained no substance soluble in ether, b u t dissolved partially in alcohol, t h e alcoholic extract depositing #-aminophenol hydrochloride on evaporation. 2 . 0 0 0 g. were boiled with alcohol and filtered on a weighed Gooch crucible. The insoluble residue was well washed with hot alcohol. and dried t o cons t a n t weight in vacuo over sulfuric acid. I t weighed 0.728 g. and consisted of pure starch. The filtrate was evaporated t o dryness and t h e residue dried at 11j o ;i t weighed 0.998 g. Another 2 . 0 0 0 g. sample were heated in t h e oven at I I ~ O t o constant weight; i t lost 0.308 g. The material thus consisted of 9-Aminophenol hydrochloride.. .................... Starch Moisture
.......................................... ........................................
Per cent 49.9 36.4 15.4
101.7
1g18)-This consisted of technical $-aminophenol hydrochloride, without a trace of methylated product. “METOL” (APRIL 1g18)-The label claimed t h e contents t o be “Hydrochloride of methyl-$-aminom-cresol guaranteed 96.3 per cent pure.” The material consisted entirely of ;-amino- 2-cresol hydrochloride, without a trace of methylated product. “ M E T O L SUBSTITUTE” (APRIL 1g16)-The material was first extracted with ether, a n d t h e filtrate found t o contain only pure hydroquinone. 2.7654 g. gave 0.5122 g. of hydroquinone, or 18. 5 per cent. T h e residue showed t h e presence of sulfite and sulfate as t h e only acid radicles; on ignition, a residue consisting of sodium salts was left. p-Methylaminophenol was found by t h e usual methods, and t h e behavior of t h e material led t o t h e suspicion t h a t cane sugar was present. This was confirmed by boiling with strong hydrochloric acid, when t h e characteristic brown color and odor of caramel were developed. Further examination failed t o show t h e presence of other substances. The portion insoluble in ether was dissolved in water and diluted t o 50 cc.; this solution in a 20 cm. tube gave a rotation of 2-90’, using mercury green light, corresponding t o 0.932 g. cane sugar in t h e sample, or 33.7 per cent. Another portion of t h e original sample was ignited in a platinum crucible a n d t h e residue coaverted into sodium sulfate; 1.3604 g. gave 0.5319 g. of sodium sulfate, corresponding t o 34.7 per cent of sodium sulfite. (The sulfurous acid content was not determined as a check.) For estimating t h e p-methylaminophenol sulfate, a portion was digested with sulfuric acid and t h e nitrogen determined b y t h e Kjeldahl process; 1.4880 g. required 8 . 6 cc. of N / I O acid, corresponding t o 0.148 g. p-methylaminophenol sulfate, or I O per cent. The material t h u s contained: “METOL”
(APRIL
.................................... ....................................... .................................... .....................
Hydroquinone Cane sugar Sodium sulfite $-Methylaminophenol sulfate..
Per cent 18.5 33.7 34.7 10.0 96.9
T H E JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
Nov., 1918 “METOL
SUBSTITUTE”
(JUNE
1g16)-The
material
o h treatment with ether yielded a soluble constituent
which was identified as pyrogallol; t h e residue, which contained no nitrogenous matter, consisted entirely of sodium sulfite; t h e ethereal extract from 5.1215 g. gave, on evaporation, I . 3050 g. of pyrogallol or 2 5 . 5 per cent; t h e residue was acidified and t h e sulfurous acid distilled into alkali, which was then diluted t o zoo cc. Of this solution 15.9 cc. were required b y 60 cc. of standard iodine solution, equivalent t o 50.0 g. sodium sulfite per liter, corresponding t o a total of 3.773 g. sodium sulfite, or 73.8 per cent. Another sample was ignited with sulfuric acid: I . 2 7 3 0 g. gave 1.0455 g. sodium sulfate, corresponding t o 0.9280 g. sodium sulfite or 72.9 per cent. The material thus consisted of:
...................................... ....................................
Pyrogallol.. Sodiumsulfite
Per cent 25.5
73.4
__
98.9
895
I o d i n e e s t i m a t i o w 0.8996 g. gave 0.0613 g. AgI. Expressed as potassium iodide, 0.0487 g., or 5 . 4 per cent. S d j t e e s t i m a t i o n : I . 2140 g. required 36. o cc. of standard iodine solution ( I liter corresponding t o 50. o g. of anhydrous sodium sulfite) corresponding t o 0.179 g. or 1 4 . 7 per cent sodium sulfite. A l k a l i metals: 0 . 2135 g. gave 0 . O j I Z g. mixed sodium and potassium sulfates. This corresponds to 5 . 4 per cent potassium iodide plus 1 4 . 7 per cent sodium sulfite plus 3 . 7 per cent sodium carbonate. N i t r o g e n e s t i m a t i o n (Kjeldahl) : 0.6030 g. required 11.5 cc. of N / I O acid, corresponding t o 0.198 g., or 3 2 . 8 per cent of p-methylaminophenol sulfate. Composition :
................................. .................... ................................... ...............................
Hydroquinone.. P-Methylaminophenol sulfate.. Sodium sulfite Potassium iodide.. Sodium carbonate..
..............................
Per cent 52.0 32.8 14.7 5.4
3.7 108.6
DEVELOPING AGENT (JULY 1g16)-Ether dissolved out a small amount of dark smeary material, which was not further investigated. The residue, on further examination, was found t o consist of impure p-aminophenol hydrochloride mixed with lead chloride and a small amount of lead sulfate. The lead was determined by ignition with sulfuric acid: 1.7130 g. gave 1.1270 g. of lead sulfate, or 0.429 equivalent of lead per I O O g. of sample. I n another sample chlorine and nitrogen were determined b y collecting in alkali the gases evolved on heating with sulfuric acid in the Kjeldahl process: 1.6070 g. were heated with 2 5 cc. of sulfuric acid, the gases evolved during t h e early stages of digestion being absorbed in 2 5 cc. of I O per cent alkali. This was diluted t o IOO cc. I O cc. of t h e solution required 22.6 cc. of N / z o silver nitrate after deducting t h e blank test, corresponding t o 0 . 7 1 0 equivalent of chlorine per I O O g. of sample. The ammonia required 46.4 cc. of N / r o acid, corresponding t o 0 .289 equivalent per I O O g. of sample. Deducting this leaves 0 . 4 2 I equivalent of chlorine combined as lead chloride; again deducting, there remains o . 008 equivalent of lead sulfate. Composition of IOO g. of sample:
.............................. ...........................
Impure p-aminophenol hydrochloride.. Lead chloride.. Lead sulfate.
Per cent 0.289 equivalent or
42.1
0.421 equivalent or 58.5 0.008 equivalent or 1.2
101.8
The above analysis is of course accurate only t o about I or 2 per cent, especially in t h e figure for p-aminophenol since all nitrogenous matter has been calculated as 9-aminophenol hydrochloride. DEVELOPING A G E N T (SEPTEMBER rg16)-This material was stated b y its label t o be “Identical t o Metol.” On treatment with ether a considerable quantity entered into solution; t h e ethereal extract, on evaporation, left hydroquinone: I . 2140 g. gave 0 . 6 3 0 0 g. or 5 2 . 0 per cent of hydroquinone. The insoluble portion was found t o contain sulfite, sulfate, carbonate, iodide, sodium, potassium, and a salt of p-methylaminophenol.
METOL SUBSTITUTE (JUNE 1g18)-The material was extracted with ether, which, on evaporation, left no residue. Methyl alcohol dissolved a considerable proportion; t h e filtrate, on evaporation, left a residue consisting of pure ammonium p-toluenesulfonate, which was identified b y t h e preparation of t h e corresponding sulfonic chloride and sulfonamide, both of which had the correct melting points. Further examination showed t h e presence of a salt of p-methylaminophenol and a small amount of some sodium salt. Sulfate was found t o be present. As ammonium p-toluene sulfonate has no developing action, the principal interest lay in t h e proportion of p-methylaminophenol present. A weighed quantity was accordingly dissolved in water and heated t o boiling. T o t h e boiling solution an excess of sodium carbonate solution containing a small amount of sodium sulfite mas added, and t h e mixture boiled until every trace of ammonia was expelled. The residue was then immediately acidified with dilute sulfuric acid, and t h e nitrogen determined by the Kjeldahl method: 0 . 1 2 0 0 g. required 8 . j cc. of N / I O acid corresponding t o 0.146 g., or 1 2 . o per cent of methylaminophenol sulfate. The material thus contained I 2. o per cent p-methylaminophenol sulfate, t h e remainder consisting of ammonium $-toluenesulfonate together with a small proportion of sodium salts.
ADULTERANTS-These are of such diverse nature t h a t i t is impossible t o suggest any general lines of examination. Among t h e adulterants and useless substitutes t h e following have been encountered: Starch Cane sugar Citric acid Sodium formate Potassium oxalate Rochelle salt Potassium ferrocyanide Boracic acid Borax
Potassium bromide Potassium iodide Potassium nitrate Sodium chloride Sodium sulfate Sodium sulfite Sodium bisulfite Sodium sulfide Sodium hydroxide
RESEARCH LABORATORY EASTMAN KODAKCOMPANY ROCHESTER, N. Y.
Sodium carbonate Ammonium chloride Ammonium sulfate Calcium sulfate Magnesium sulfate Lead chloride Lead sulfate
