« PoprzedniaDalej »
, } Sept. 22, 1876. Limited Oxidation of Essential Oils.
127 Glasgow alone dispose annually to farmers no less than / described, peroxide of hydrogen, and camphoric acid (both 200,000 tons, at prices varying from 2s. to 2s. 6d. per ton.* of which may result from the action of water upon cam
The final argument of the Royal Commissioner is that a phoric peroxide, C1,H2404), acetic acid, camphor, and chemical process would cost Glasgow £80,000 per year, certain other less defined substances. The oil itself including interest upon capital and expenses, taking the increases in specific gravity and contains after this experience of Leeds as a guide. This is founded upon the treatment certain oxidised bodies, among which is a assumption that the cost of the process would be the same further quantity of this camphoric peroxide. here as at Leeds, and, secondly, that the product is un- I have been able to indicate the rate at which this saleable.
oxidation takes place, and to investigate more fully the Judging from the experience of Leeds, the cost of nature and uses of the solution I have described. And in chemicals required for dealing with Glasgow sewage would doing so I have experimented with large earthenware be 43,800 annually, equal to about 1os. per ton of sewage vessels arranged in a series like so many Wolffe's bottles, mud.
each of about 20 gallons capacity. The substitution of the carbonised shale for the char- The oxidation proceeds very slowly at first, the rate coal, &c., bought at Leeds would probably reduce the being indicated by the estimation from hour to hour of expenses to 55. per ton-making the total £56,000; the the peroxide of hydrogen which is formed ; but when total expense would then run thus
once the oxidation has fairly set in, it proceeds more Chemicals
rapidly, with increasing production of peroxide of hydro
£20,000 annually. Working expenses
gen and the other products, the amounts of which are
16,000 Interest on capital
simply limited by that of the turpentine itself. Now, 20,000
assuming the operation to be started with a given quantity
of turpentine in the presence of a given quantity of water £56,000
at, we will say, 60° C., the turpentine begins slowly to Against this must be set the value of the manure. At
oxidise and produce the bodies named, which then pass the price of street-sweepings it would be £25,000, and at into solution, while the oil itself increases gradually in a little more than double the price would cover the costs specific gravity, a phenomenon which is accompanied by of the process; whilst, on the other hand, the interest
a gradual rise in its boiling-point. Now, if no fresh tur. upon an expenditure of two and a half millions of money pentine be added to that already in operation there will in engineering works would be £100,000 per annum.
come a time when the percentage of peroxide of hydrogen Before leaving this subject it may be remarked that ex.
is at a maximum, and then if the blowing be continued periments made in the neighbourhood of the metropolis after that time it slowly diminishes, in fact at about the have been on such a small scale that they are utterly use.
same rate that it forms. If, on the other hand, the tur. less in judging of the results which could be attained with pentine which is blown away as vapour be condensed and the sewage of a large city.
returned to the oxidiser, or what amounts to the same This is noticeable in reading reports of the costs of mani. thing, if fresh turpentine be added the oxidation proceeds pulation, and more particularly the cost of drying sew
as rapidly as ever, while there is no limit to the amount age mud. Of course, large cities like Glasgow, near ex
of peroxide of hydrogen which is formed. tensive coal-fields, have enormous advantages in cheap
It is remarkable that turpentine in the act of being coals, but the evaporation of a given amount of water when oxidised is capable of imparting to fresh turpentine the heat is properly and continuously applied is subject to
same and equal facility to absorb oxygen. definite rules, and the results I have seen in printed state
The slow rate at which the oxidation of fresh turpentine ments of costs show such a grave departure from the results proceeds, and the greater rate attained after the molecules of engineering practice, that I should feel confident of have undergone the change which induces a rapid oxidation much more successful results in the intelligent manage.
is seen by the following figures which relate to an experi. ment of the sewage of extensive centres of population, such
ment conducted on some gallons of turpentine and water as are found in this city.
Grms. of H,0, in 100.c.c. Solution. After 37 hours 0'0651 grammes H2O2
41 REPORT ON THE LIMITED OXIDATION OF
0-3000 ESSENTIAL OILS, PART IV.;
0°4500 CONTAINING A PRELIMINARY REPORT
The increase that takes place in the specific gravity of ON THE ETHERS.
the oil of turpentine as the oxidation proceeds is ex. By CHARLES T. KINGZETT, F.C.S., London
emplified by the following figures which relate to another and Berlin, &c. experiment:
0.864 originally A. Oxidation of Turpentine.-Since my last publication
After 24 hours the sp. gr. of the oil =0.880
=0.888 ubservations upon the aqueous solution that results when
= 0'949 turpentine is oxidised by a current of air in the presence of water. This opportunity has been afforded me while
Againexperimenting upon no less than fifty gallons of turpentine;
=0.8886 and while in no one particular have I to withdraw or alter
=0.8996 any of my original statements, certain matters have come
=0*9обо more strongly before my observation which are worthy of
=0*9136 some notice. Before proceeding to summarise these it
= 0'9366 will be well to recapitulate the main products of the
=0.9476 oxidation. My past researches, then, have established that turpentine yields when oxidised in the way I have
The increase in the boiling point of the oil as the
oxidation proceeds is illustrated by the following deterGlasgow." Preports of the Cleansing Committee of the Police Board of minations, which relate also to a different experiment.
The turpentine used in this experiment boiled as indi. 1 Read before the British Association (Section B.), Glasgow Meeting. I cated in column (1).
Sept. 22, 1876. (1)
peroxide of hydrogen to the gallon also contains Original Oil.
Oil after 24 hours' After 27 hours' 367 grains of camphoric and acetic acids. But the per-
centage of each constituent and the strength of the whole 10 p. c. over at 157° C. 1б2° С.
mixture are matters to a great extent under control in the 159 165:50 166
method of preparation. 30 160 168 170
B. Antiseptic and Disinfecting Powers of the Solution.40 160 171 171
In studying the properties of the solution I have described 50 160:5 174 174
I discovered that it possessed great power as an antiseptic бо 161 181 185
and disinfectant, and I was led to investigate this matter 162 193 206
somewhat fully, also to enquire into similar properties 8o 164
possessed by the known constituents of my solution, and 166
in comparison with those of salicylic acid.
In the experiments given at foot of page the solu. In regard to these boiling-point determinations I should tion employed was of that general strength I have in. remark that in each case 100 c.c. were subjected to distil- dicated above, and contained 2.5 grms. H202 per litre. lation in the way that is usual in these matters, and the All these experiments were made during October and temperature recorded after each 10 c.c. was collected. It November, 1875. is necessary also to point out that the oil, although it has Those now to be given were made during June, July, been oxidised in the presence of water, is yet so full of and August, 1876. The antiseptic solution employed was the organic peroxide I have discovered and described in not so strong as that used above. my previous researches, that when it has once reached a temperature of 160° C or less, a violent effervescence sets
With 3.5 c.c. An. With 175 c.c. With 4 c.c. neu in from the escape of oxygen, and much heat is eliminated,
tiseptic = 10 Antiseptic tral Antiseptics as indicated by the rise in the thermometer after the lamp
5 per cent. = 11 per cent. has been removed. I shall conclude this part of my paper
of Kept fresh Fresh for 21 Fresh for 35 by stating that having been led by the value of the solu- egg, 35 c.c.
for 35 days,
days, then days, then tion as an antiseptic and disinfectant to a:tempt the
mould apmanufacture of it and the residual oil I have described,
peared. No peared. No on a commercial scale, I have devoted a great deal of time
No stink. smell.
smell. to the study of those conditions which are calculated to lead to the most desirable results. In this attempt I have
The only other alteration in each case was a slight received much help from Mr. J. Brown, F.C.S., which I darkening to brown in the colour of the albumin. But have the pleasure to acknowledge. For I have been so
after each experiment the albumin had still its coagulable far successful as to obtain under certain conditions readily character and was not otherwise changed. from an inconsiderable amount of turpentine, water, and
After dipping in the same solution, brain matter also air a solution containing such large quantities of peroxide, kept fresh for several days, whereas without such treatof hydrogen and the other substances above named, as to ment, it stunk on the next day. qualify it for purposes and uses upon which I propose to Milk was also preserved for a much longer period than dwell in Section B of my report. ` I find that a solution without, but not for so long a period as in the winter containing so much peroxide of hydrogen as to be capable months. of evolving from 1 litre either 1531 c.c. oxygen or 3062 c.c.
Beer was also thoroughly preserved for a number of oxygen, according as one or both molecules of oxygen days, as long as observed; so also was blood serum. (in H202) are affected, has all the properties which i Stinking water recovered and remained good with it for propose to describe ; but before doing this I must add that months. these properties are far from being entirely dependent amined seriously the influence of less percentages than
In conclusion I would only add that I have never exupon the peroxide of hydrogen contained. They are related also to the camphoric acid and other constituents, those detailed, but there can be no doubt that much less for they are not seriously impaired by the total destruction quantities could be used in many cases with the same of the peroxide of hydrogen. This I have substantiated effects as those described. In fact this would be necessary in an experimental way, and shall now proceed to describe with articles of food on account of the aromatic odour and the experiments themselves. These I shall only preface peculiar taste of the solution. by stating that a solution which contains 323 grains of
(To be continued).
Article Experimented upon. Egg albumen. 50 c.c. containing 10 c.c. white of egg in each
case. Must from muscatel grapes, 50
c.c. taken in each experiment. Milk. 200 c.c, in each case.
Urine, 60 c.c. in each case.
case. Milk, 160 c.c. in each case.
5 c.c. neutralised by soda
= 10 per cent.
= 20 per cent.
= 5 per cent.
= 10 per
= 6 per
Observed 24 days still
fresh as at first.
aster, solid on 7th day.
no longer observed. Kept fresh 15 days, no
on 7th day, no longer
With equal vols. of water
and no antiseptic. Began to stink on
2nd day after. Soon fermented at
40°C., giv. alcohol. Solid and sour on 3rd
day after, Bad smell and day,
stunk on 3rd day. Stunk on 3rd day
after. Sour and solid on the
2nd day after. Stunk on the 3rd
day. Bad on the 2nd day,
very bad on 3d day. Thin films on 2d day,
fungus over sur. face on 3rd day.
Bitter Beer, 160 c.c. in each case.
Chemical Constitution of the Alcohols. Sept. 22, 1876.
129 THE CHEMICAL CONSTITUTION OF THE remains behind in the form of an insoluble amorphous HIGHER ACID HETEROLOGUES
white powder. From this the ammonium glyoxylate may OF THE
be readily obtained by treatment with aqueous ammonia. ETHYLIC, GLYCOLIC, AND GLYOXALIC
Now, it is stated by Mír. Perkin that when this ammonium.
salt is evaporated in vacuo, the solution, although neutral ALCOHOLS,
at first, always becomes acid, and that without loss of AS VIEWED AND INTERPRETED FROM THE STANDPOINT ammonia, and ultimately yields a crystalline product OF THE TYPO-NUCLEUS THEORY.
having the same outward appearancc and empirical (Concluded from p. 122.)
formula as the soi-disant ammonium glyoxylate which
Dr. Debus professes to have got by similar treatment, and By OTTO RICHTER, Ph.D.
an aqueous solution of which, he assures us, gave all the
reactions of a genuine ammonium-salt. Mr. Perkin, on PART II.
the other hand, was not slow in drawing attention to the On the Principal Molecular Changes which ensue when
fact that his crystalline powder, which I take to be a gly. the Dry or Dissolved Combinations of the Bromacetic, oxylamide with the formulaDibromacetic, and Bromo-glycolic Acids, with the Alkalies, Oxide of Silver, or Oxide of Ammonium, are
F0202,2F004–2H2N2 subjected to the Decomposing Influence of Temperature. was very prone to assimilate water with reproduction of When the dry bromacetates of potassium, silver, or the original ammonium-salt,-a circumstance quite in ammonium are heated up to a certain point they are found keeping with his view of the matter. In weighing the to yield the bromides of these metals along with glycolide, arguments brought forward by these two distinguished to which I ascribe the formula
London chemists, I cannot help believing in the identity H202.
of the crystalline powders obtained by Mr. Perkin and F0202,2C202,
Dr. Debus, and that they possess the chemical constitution a formula which must not be confounded with that of the unexpected manifestations of acidity, &c., during the
which my formula attributes to them. As regards the someric glyoxal,-H2O2.
process of evaporation, I may remark that a similar phe
nomenon was noticed by Mr. Perkin in another experi2C202,2F09.
ment, with this material difference, however, that the The formation of this body is due to the splitting up of change in question was superinduced not by the abstracthese bromacetates into the hydrates of their respective tion of the aqueous solvent, but, on the contrary, by its bases, and the subsequent transposition of the latter with addition. In the words of Mr. Perkin, “When bromo. the colligated formyl-chloride of the residual oxybrom glycolate of silver was heated with a large excess of absoaceten, Fo2Br2,C202. When heated in the presence of lute alcohol in a sealed tute, the latter, after several water the aforesaid bromacetates will again produce the hours' heating, was found to contain a clear liquid and á metallic bromides, but instead of glycolide we shall now bright yellow powder. The liquid proved to be totally obtain the water-salt of glycolic acid. Let us, in the neutral to test-paper, which in contact with a drop of next place, contemplate the effects of heat upon dry am
water began to turn red, plainly proving that the newlymonium bromacetate in the presence of ammonia. The formed glyoxylic ether was undergoing decomposition." chief products of this reaction are found to be ammonium As I intend reverting again to these remarkable manifes. bromide and B glycolamide or glycocoll, to which I assign tations, I shall proceed to describe the molecular changes the formula
when glyoxalate of water is heated with absolute alcohol H2O2. H2O2.
to 120°. The resulting product is designated by the Fo202,2C20-2H2N2,
author as the diethyl-glyoxylate of ethyl, but if my mode
of reasoning is correct its proper name will be the ethyl. which implies that, in harmony with established facts, glyoxylate of diethyl, with the formulathis body is endowed with the twofold character and functions of a feeble organic base and a feeble organic
Et202. 2(Et202). acid. In this metamorphosis we have again, in the first
F0202, 2C204. stage, the formation of ammonium bromide and glycolide ; By this formula the compound before us is shown to be a but as regards the precise nature of the molecular changes triatomic ether-salt of glyoxylic acid, in which the acid attending the second stage of the process, and which are due to the substitutional action of ammonia on the newly 2H; 2C2O5, as it exists in the water-salt, but the bibasic
principal is no longer the monobasic oxyformic acid, formed glycolide, I am obliged to reserve my explanations for another opportunity. The same remark applies also carbonic acid, capable of saturating two molecules of to the a glycolamide,
ether base. Let us now imagine the replacement of one
of these two ether molecules by the molecule of basic H2O2.
water which is engendered during the conversion of the F0202,2F002-2H2N2,
aforesaid oxyformic into carbonic acid, and it becomes which derives its origin from the substitutional action of evident that the resulting compound, which I hold to be
identical with the well-known carbovinate of water, — ammonia on the water-salt of glycolic acid. Let us now proceed to consider the effects of tempera
H2O2. H2O2. ture upon the metallic dibromacetates. According to Mr. Perkin, when dibromacetate of silver is strongly heated it splits up into silver bromide and an insoluble ought to betray, as it does in fa&, a distinctly acid re
action. powder, which is evidently bromo-glycolide,
The preceding remarks will, I think, enable the reader Fo2Br2,2C2O4.
to decipher the whole process of etherification as it When the dry bromo-glycolate of sodium-obtained by stands with regard to the glyoxylate, where three moletreating the bromo-glycolide with hydrate of sodium-is cules of ethylic alcohol are successively drawn into the strongly heated in its turn, and the contents of the retort sphere of chemical reaction. We have already seen that brought into conta& with water, the sodium bromide is the action of alcohol on bromo-glycolate of silver gives dissolved out, while glyoxylide,
rise to the neutral monobasic glyoxylate of ethyl,-
Enamelled Cooking Vessels.
Sept. 22, 1876.
and there is nothing to hinder us from assuming that the PROF. DITTMAR AND THE “ ANALYST." same compound is engendered by the action of the first molecule of alcohol on the glyoxylate, while two molecules of water are eliminated. The ether being now in Perhaps some of our readers may have seen in the official the presence of that element, which is capable of pro- organ of the Society of Public Analysts, along with other voking the series of molecular changes I have already startling matter, a report of the prosecution of a certain indicated, is speedily made to pass into the isomeric mo- Mr. McKinnon, of Glasgow, for selling adulterated butter, dification of the acid bibasic glyoxylate of ethyl, - and a leading article commenting in very severe terms H2O2. Et202. H2O2.
upon the evidence of Prof. Dittmar, who was a witness on F0202,2C204,
the trial. This gentleman is made to say that " he did
not think Muter's system was the correct one, and was of which, with a second molecule of alcohol, may lead to the opinion that the butter was quite sound.” From a letter formation of the neutral glyoxylate of diethyl,
sent by Prof. Dittmar to the Glasgow Herald the report H2O2. 2(Et202).
in the Analyst seems by no means accurate. He did not F0202, 2C204,
pronounce the butter " quite sound,” but declared that it or else the acid ethyl-glyoxylate of ethyl,
was “more likely than not to be contaminated with foreign Et202. Et202. H2O2.
fat," though he did not feel free to swear to the presence F0202, 2C204,
of this impurity. He did not, from any evidence to which or, finally, the neutral ethyl-glyoxylate of ethyl,
we have access, " deliberately prefer old and worthless
methods," but merely expressed a doubt-not, in our Et202. Et202.
humble opinion, quite unpardonable--whether the method F0202,2F00s,
of Dr. Muter had as yet been verified by a sufficiently wide but, whichever way we take it, it becomes certain that the experience. In short, it would appear that our contemend product of this lengthy and complicated reaction porary's report goes beyond the facts of the case, and that must be the triatomic ethyl-glyoxylate of diethyl, as his leading article goes no less decidedly beyond the formulated above.
report. From the preceding explanations the reader will no We know that there are in connection with the Analyst longer be at a loss to comprehend the true cause of the chemists of well-earned reputation, equally anxious for the hitherto unaccountable appearance of acidity on the part advance of their science and for the elevation of their proof the ammonium glyoxylate while it is being evaporated, ) fession. To these gentlemen at any rate, if not to the -a discrepancy which Mr. Perkin would fain attribute to writer of the article in question, we would, in all courtesy, a want of stability and to its not possessing the character suggest that such attacks as that in the last number of the of a true salt, but which is really due to the different Analyst merely strengthen the hands of the common positions a particular molecule of hydrogen is destined enemy-those, namely, who consider chemical analysis as to occupy in the system, and to the different duties and altogether untrustworthy, and who regard chemists them. functions it is thereby made to discharge. Accordingly selves as either “imbecile," "incompetent," or even as the neutral or a modification will require to be represented "impostors." by the formula
ENAMELLED COOKING VESSELS.
Ar the country meeting of the Society of Public Analysts and the same constitutional differences will be traceable held in Glasgow, during the recent visit of the British in their respective amides, the a glyoxylamide being ex- Association, a paper was read by Mr. Robert R. Tatlock, pressed by the formula
F.R.S.E., F.C.s., Glasgow, on “ Enamelled Cooking H2O2.
Vessels." He stated that in some instances the milk. F0202,2100,- 2H2N2,
white porcelainous enamel, with which cast-iron cooking and the ß glyoxylamide by the formula
vessels are now so commonly prepared, is of such a char
acter as to be objectionable in the highest degree on acH2O2. H2O2.
count of the easy action upon it of acid fruits, common F0202,2C203 - 2H2N2.
salt, and other ordinary dietetic substances, by means of Finally, as regards the third isomeride of this group, viz., which lead and even arsenic are dissolved out in large the ammonium glyoxylate, with the formula
quantity during cooking operations. The following Am202.
analyses were given of three enamels, the samples having 2C202,2F003,
been taken from three cast-iron pots made by different and which at all events must be regarded as a true ammo.
No. 1. No, 2. nium-salt, I can only regret that this interesting compound has not yet received that amount of attention which it Silica ..
42:40 42'00 assuredly deserves.
8:00 2.88 6'06 In drawing to a close, I may yet be permitted to ex- Oxide of iron
2'04 4'04 press an anxious hope that our leading experimentalists Lime
3'02 0:16 0978 may soon condescend to re-investigate this and other
Magnesia kindred problems on the principles and in the spirit of my Oxide of lead
absent “ Typo-Nucleus” theory,-a task for which these gentle
5.61 7.99 6:46 men are so well qualified, not only in virtue of their Soda
20 67 14:67 19:25 superior talents and their exalted professional position, Phosphoric acid but more particularly on account of the rare practical tact Arsenious acid
0:42 and experience which enables them to cope with the Carbonic acid
0-30 absent absent many difficulties that are sure to be encountered in this Borax ..
3:45 1°70 department of organic chemistry. ERRATA.-P. 121, line 10 from bottom, for"
-"glyoxalate e" read "glyoxylate." Line 14 from bottom, for “ bromoglyoxylate" read "bromoglyoxalate."
131 The author shewed that it was not so much on account Action of Hydrate of Potassa on Anthraflavic Acid.of the presence of large proportions of lead and arsenic | This acid is less readily attacked by potassa than the iso. that the enamels are so objectionable, but because they acid, and there ensues partial carbonisation. This may are so highly basic in their character that they are readily be avoided by using a strong potassic-lye under pressure, acted upon by feebly acid solutions, the lead and arsenic instead of melting, and consequently employing a lower being thereby easily dissolved out. He showed that the temperature. ratio of the bases to the silica in the No. I was as I to The undecomposed anthraflavic acid is removed by 1958; in the No. 2 as 1 to 0·79; and in the No. 3 as I to boiling with baryta-water. The flavo-purpurin formed is 0976. Ai per cent solution of citric acid boiled in the readily soluble in alcohol, and crystallises in gold-coloured No. 1 did not affect it in the slightest, while in the case of needles. the No. 3 the glassy surface of the enamel was at once Analysis shows its composition as C14H80s. roughened and destroyed, and lead dissolved out to such
Obtained. an extent as to give immediately a dense black precipitate
C,H,Og. with sulphuretted hydrogen. He thought that no enamel
65062 should be admitted to use unless it was totally unaffected
Properties of either the use of such poisonous ingredients as lead and Anthrapurpurin.
Flavo-purpurin. arsenic in large quantity should be entirely discontinued, Orange needles. Anhy- Gold - coloured needles. or that the composition otherwise should be of such a drous.
Anhydrous. character as to ensure that none of the poisonous substances could be dissolved out in the circumstances under alcohol.
Readily soluble in boiling Readily soluble in cold
alcohol. which the vessels are used.
Sparingly soluble in boil. Sparingly soluble. ing water.
Solution becomes red on Solution remains yellow.
prolonged boiling. ANTHRAPURPURIN
Sparingly soluble in ether.
Soluble in boiling glacial
acetic acid, and crystallises
of needles. IN a former communication we described certain substi
Soluble in concentrated Soluble in concentrated tution-products of isoanthraflavic acid and anthraflavic acid, to show the difference of these two bodies also in sulphuric acid with a red- sulphuric acid with a reddish their derivatives. We now describe certain experiments
Soluble made to ascertain the part which these substances play in with a violet colour. The with a purple colour redder
in potassa-lye Soluble in potassa-lye the manufacture of alizarin. We may ask how they are formed; whether they pass into alizarin on prolonged re
tone is redder than that of a than anthrapurpurin, but action with alkali; or, as seems most probable, whether
solution of alizarin.
not so red as purpurin. On
dilution or addition of alkali they yield oxidation-products, and consequently purpurins ?
but slightly diluted the coWe have ascertained that each of the acids yields a
lour appears of a pure red. purpurin, isoanthraflavic acid forming the anthrapurpurin
The colour disappears on described by Perkin and anthraflavic acid-a new com.
standing. pound, which we have provisionally named flavopurpurin. baryta water with a violet baryta water with a red
Sparingly soluble in hot Sparingly soluble in hot The statement of one of us that anthraflavic acid is converted into alizarin on fusion with alkali must therefore be
The solution shows ab. corrected. *
Absorption-bands in Action of Hydrate of Potassa upon Isoanthraflavic Acid.
Soluble in ammonia with Soluble in ammonia with -If the aqueous solution of the potassic salt of this acid
a violet colour. Solution is heated with caustic potassa the originally red colour
a yellowish red colour. So. shows small bands.
lution shows no bands. passes gradually into a violet, and particularly quickly when the temperature approaches the melting point of ate with a violet colour.
Soluble in sodium carbon. Soluble in sodium carbonpotassa.. When the intensity of the violet no longer in.
ate with a yellowish red
colour. creases the operation is interrupted, the melt dissolved in
Alcoholic lead acetate Alcoholic lead acetate water and supersaturated with hydrochloric acid. A yel. low gelatinous precipitate falls, which is treated with cold
gives a purple precipitate gives a red-brown precipibaryta water to remove some undecomposed isoanthra
which dissolves with a violettate, very sparingly soluble Aavic acid. The residual lake, on decomposition with of the precipitant.
colour on boiling with excess in excess with a red colour. hydrochloric acid, yields pure anthrapurpurin, which can be readily obtained in long orange needles by crystallisa- gives a fine violet solution. gives a red solution.
Alcoholic copper acetate Alcoholic copper acetate tion from alcohol. That we have here a trioxyanthraquinon appears from
Sparingly soluble in alum. Ditto. the following analyses :
Melting-point above 330°. Ditto.
Sublimes in orange nee- Sublimes in long needles
Alkaline solution gives Alkaline solution shows 3:28
two absorption-bands having also two bands, but more The properties are essentially as stated by Perkin.+
the same position as those remote from the red, and We shall describe them more fully below, in contrast with
also a broad stripe in the those of the new purpurin.
blue. The melting-process works very smoothly, almost the To ascertain whether the above-described reactions theoretical yield of anthrapurpurin being obtained. might not be modified by small quantities of impurities, * E Schunck, Proc. Lit. and Phil. Soc. Manchester, 1871, 133.
we converted both the purpurins into acetyl compounds, + Perkin, Journ. Chem. Soc., Ser. II., vol. xi., p. 425.
re-crystallised them until the melting point became con