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CHEMICAL NEWS,

Sept. 22, 1876.

Limited Oxidation of Essential Oils.

Glasgow alone dispose annually to farmers no less than 200,000 tons, at prices varying from 2s. to 2s. 6d. per ton.* The final argument of the Royal Commissioner is that a chemical process would cost Glasgow £80,000 per year, including interest upon capital and expenses, taking the experience of Leeds as a guide. This is founded upon the assumption that the cost of the process would be the same here as at Leeds, and, secondly, that the product is unsaleable. Judging from the experience of Leeds, the cost of chemicals required for dealing with Glasgow sewage would be 43,800 annually, equal to about 10s. per ton of sewage mud.

The substitution of the carbonised shale for the charcoal, &c., bought at Leeds would probably reduce the expenses to 5s. per ton-making the total £56,000; the total expense would then run thus

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Against this must be set the value of the manure. At the price of street-sweepings it would be £25,000, and at a little more than double the price would cover the costs of the process; whilst, on the other hand, the interest upon an expenditure of two and a half millions of money in engineering works would be £100,000 per annum. Before leaving this subject it may be remarked that experiments made in the neighbourhood of the metropolis have been on such a small scale that they are utterly useless in judging of the results which could be attained with the sewage of a large city.

This is noticeable in reading reports of the costs of manipulation, and more particularly the cost of drying sewage mud. Of course, large cities like Glasgow, near extensive coal-fields, have enormous advantages in cheap coals, but the evaporation of a given amount of water when heat is properly and continuously applied is subject to definite rules, and the results I have seen in printed statements of costs show such a grave departure from the results of engineering practice, that I should feel confident of much more successful results in the intelligent management of the sewage of extensive centres of population, such as are found in this city.

REPORT ON THE LIMITED OXIDATION OF
ESSENTIAL OILS, PART IV.;
CONTAINING A PRELIMINARY REPORT
ON THE ETHERS.

By CHARLES T. KINGZETT, F.C.S., London
and Berlin, &c.

A. Oxidation of Turpentine.-Since my last publication on terpenes and the products of their limited oxidation, I have had the opportunity of repeating the whole of my observations upon the aqueous solution that results when turpentine is oxidised by a current of air in the presence of water. This opportunity has been afforded me while experimenting upon no less than fifty gallons of turpentine; and while in no one particular have I to withdraw or alter any of my original statements, certain matters have come more strongly before my observation which are worthy of some notice. Before proceeding to summarise these it will be well to recapitulate the main products of the oxidation. My past researches, then, have established that turpentine yields when oxidised in the way I have

* "Reports of the Cleansing Committee of the Police Board of Glasgow." Read before the British Association (Section B.), Glasgow Meeting.

127

described, peroxide of hydrogen, and camphoric acid (both of which may result from the action of water upon camphoric peroxide, C10H1404), acetic acid, camphor, and certain other less defined substances. The oil itself increases in specific gravity and contains after this treatment certain oxidised bodies, among which is a further quantity of this camphoric peroxide. I have been able to indicate the rate at which this oxidation takes place, and to investigate more fully the nature and uses of the solution I have described. And in doing so I have experimented with large earthenware vessels arranged in a series like so many Wolffe's bottles, each of about 20 gallons capacity.

The oxidation proceeds very slowly at first, the rate being indicated by the estimation from hour to hour of the peroxide of hydrogen which is formed; but when once the oxidation has fairly set in, it proceeds more rapidly, with increasing production of peroxide of hydrogen and the other products, the amounts of which are simply limited by that of the turpentine itself. Now, assuming the operation to be started with a given quantity of turpentine in the presence of a given quantity of water at, we will say, 60° C., the turpentine begins slowly to oxidise and produce the bodies named, which then pass into solution, while the oil itself increases gradually in specific gravity, a phenomenon which is accompanied by a gradual rise in its boiling-point. Now, if no fresh turpentine be added to that already in operation there will come a time when the percentage of peroxide of hydrogen is at a maximum, and then if the blowing be continued after that time it slowly diminishes, in fact at about the same rate that it forms. If, on the other hand, the turpentine which is blown away as vapour be condensed and returned to the oxidiser, or what amounts to the same thing, if fresh turpentine be added the oxidation proceeds as rapidly as ever, while there is no limit to the amount of peroxide of hydrogen which is formed.

It is remarkable that turpentine in the act of being oxidised is capable of imparting to fresh turpentine the same and equal facility to absorb oxygen.

The slow rate at which the oxidation of fresh turpentine proceeds, and the greater rate attained after the molecules have undergone the change which induces a rapid oxidation is seen by the following figures which relate to an experi. ment conducted on some gallons of turpentine and water

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128

(1) Original Oil.

Limited Oxidation of Essential Oils.

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10 p. c. over at 157° C.

162° C.

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In regard to these boiling-point determinations I should remark that in each case 100 c.c. were subjected to distillation in the way that is usual in these matters, and the temperature recorded after each 10 c.c. was collected. It is necessary also to point out that the oil, although it has been oxidised in the presence of water, is yet so full of the organic peroxide I have discovered and described in my previous researches, that when it has once reached a temperature of 160° C or less, a violent effervescence sets in from the escape of oxygen, and much heat is eliminated, as indicated by the rise in the thermometer after the lamp has been removed. I shall conclude this part of my paper by stating that having been led by the value of the solution as an antiseptic and disinfectant to attempt the manufacture of it and the residual oil I have described, on a commercial scale, I have devoted a great deal of time to the study of those conditions which are calculated to lead to the most desirable results. In this attempt I have received much help from Mr. J. Brown, F.C.S., which I have the pleasure to acknowledge. For I have been so far successful as to obtain under certain conditions readily from an inconsiderable amount of turpentine, water, and air a solution containing such large quantities of peroxide of hydrogen and the other substances above named, as to qualify it for purposes and uses upon which I propose to dwell in Section B of my report. I find that a solution containing so much peroxide of hydrogen as to be capable of evolving from 1 litre either 1531 c.c. oxygen or 3062 c.c. oxygen, according as one or both molecules of oxygen (in H2O2) are affected, has all the properties which I propose to describe; but before doing this I must add that these properties are far from being entirely dependent upon the peroxide of hydrogen contained. They are related also to the camphoric acid and other constituents, for they are not seriously impaired by the total destruction of the peroxide of hydrogen. This I have substantiated in an experimental way, and shall now proceed to describe the experiments themselves. These I shall only preface by stating that a solution which contains 323 grains of

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CHEMICAL NEWS, Sept. 22, 1876.

peroxide of hydrogen to the gallon also contains 367 grains of camphoric and acetic acids. But the percentage of each constituent and the strength of the whole mixture are matters to a great extent under control in the method of preparation.

B. Antiseptic and Disinfecting Powers of the Solution.In studying the properties of the solution I have described I discovered that it possessed great power as an antiseptic and disinfectant, and I was led to investigate this matter somewhat fully, also to enquire into similar properties possessed by the known constituents of my solution, and in comparison with those of salicylic acid.

In the experiments given at foot of page the solution employed was of that general strength I have indicated above, and contained 2.5 grms. H2O2 per litre. All these experiments were made during October and November, 1875.

Those now to be given were made during June, July, and August, 1876. The antiseptic solution employed was not so strong as that used above.

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The only other alteration in each case was a slight darkening to brown in the colour of the albumin. But after each experiment the albumin had still its coagulable character and was not otherwise changed.

After dipping in the same solution, brain matter also kept fresh for several days, whereas without such treatment, it stunk on the next day.

Milk was also preserved for a much longer period than without, but not for so long a period as in the winter months.

Beer was also thoroughly preserved for a number of days, as long as observed; so also was blood serum. Stinking water recovered and remained good with it for months.

In conclusion I would only add that I have never examined seriously the influence of less percentages than those detailed, but there can be no doubt that much less quantities could be used in many cases with the same effects as those described. In fact this would be necessary with articles of food on account of the aromatic odour and peculiar taste of the solution.

5 c.c. neutralised by soda
= 10 per cent.

10 c.c. neutral antiseptic
20 per cent.
10 c.c. neutral antiseptic
= 5 per cent.

10 c.c. antiseptic 16 per

cent.

10 c.c. antiseptic.

10 c.c. antiseptic

cent.

10 c.c. antiseptic

cent.

= 10 per

= 10 per

1o c.c. antiseptic = 6 per

cent.
IO G.c. antiseptic
cent.

=

6 per

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CHEMICAL NEWS, 1

Sept. 22, 1876.

Chemical Constitution of the Alcohols.

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129

remains behind in the form of an insoluble amorphous white powder. From this the ammonium glyoxylate may be readily obtained by treatment with aqueous ammonia. Now, it is stated by Mr. Perkin that when this ammonium. salt is evaporated in vacuo, the solution, although neutral at first, always becomes acid, and that without loss of ammonia, and ultimately yields a crystalline product having the same outward appearance and empirical formula as the soi-disant ammonium glyoxylate which Dr. Debus professes to have got by similar treatment, and an aqueous solution of which, he assures us, gave all the reactions of a genuine ammonium-salt. Mr. Perkin, on the other hand, was not slow in drawing attention to the fact that his crystalline powder, which I take to be a glyoxylamide with the formula

H2O2.

Fo2O2,2F004-2H2N2

was very prone to assimilate water with reproduction of the original ammonium-salt,-a circumstance quite in keeping with his view of the matter. In weighing the arguments brought forward by these two distinguished London chemists, I cannot help believing in the identity of the crystalline powders obtained by Mr. Perkin and Dr. Debus, and that they possess the chemical constitution which my formula attributes to them. As regards the

a formula which must not be confounded with that of the unexpected manifestations of acidity, &c., during the someric glyoxal,

H2O2.

2C2O2,2F00.

The formation of this body is due to the splitting up of these bromacetates into the hydrates of their respective bases, and the subsequent transposition of the latter with the colligated formyl-chloride of the residual oxybrom-glycolate of silver was heated with a large excess of absoaceten, Fo2Br2,C2O2. When heated in the presence of water the aforesaid bromacetates will again produce the metallic bromides, but instead of glycolide we shall now obtain the water-salt of glycolic acid. Let us, in the next place, contemplate the effects of heat upon dry ammonium bromacetate in the presence of ammonia. The chief products of this reaction are found to be ammonium bromide and 6 glycolamide or glycocoll, to which I assign

the formula

H2O2. H2O2.
Fo2O2,2C20-2H2N2,

which implies that, in harmony with established facts, this body is endowed with the twofold character and functions of a feeble organic base and a feeble organic acid. In this metamorphosis we have again, in the first stage, the formation of ammonium bromide and glycolide; but as regards the precise nature of the molecular changes attending the second stage of the process, and which are due to the substitutional action of ammonia on the newly formed glycolide, I am obliged to reserve my explanations for another opportunity. The same remark applies also to the a glycolamide,—

H2O2.

Fo202,2F002-2H2N2,

process of evaporation, I may remark that a similar phenomenon was noticed by Mr. Perkin in another experiment, with this material difference, however, that the change in question was superinduced not by the abstraction of the aqueous solvent, but, on the contrary, by its addition. In the words of Mr. Perkin, "When bromolute alcohol in a sealed tube, the latter, after several hours' heating, was found to contain a clear liquid and a bright yellow powder. The liquid proved to be totally neutral to test-paper, which in contact with a drop of water began to turn red, plainly proving that the newlyformed glyoxylic ether was undergoing decomposition." As I intend reverting again to these remarkable manifestations, I shall proceed to describe the molecular changes when glyoxalate of water is heated with absolute alcohol to 120°. The resulting product is designated by the author as the diethyl-glyoxylate of ethyl, but if my mode of reasoning is correct its proper name will be the ethylglyoxylate of diethyl, with the formula

Et2O2. 2(Et2O2).
Fo202, 2C2O4.

By this formula the compound before us is shown to be a triatomic ether-salt of glyoxylic acid, in which the acid principal is no longer the monobasic oxyformic acid, 2H; 2C2O5, as it exists in the water-salt, but the bibasic ether base. Let us now imagine the replacement of one carbonic acid, capable of saturating two molecules of of these two ether molecules by the molecule of basic water which is engendered during the conversion of the aforesaid oxyformic into carbonic acid, and it becomes identical with the well-known carbovinate of water,

which derives its origin from the substitutional action of evident that the resulting compound, which I hold to be ammonia on the water-salt of glycolic acid.

Let us now proceed to consider the effects of temperature upon the metallic dibromacetates. According to Mr. Perkin, when dibromacetate of silver is strongly heated it splits up into silver bromide and an insoluble powder, which is evidently bromo-glycolide,

Fo2Br2,2C2O4.

When the dry bromo-glycolate of sodium-obtained by treating the bromo-glycolide with hydrate of sodium-is strongly heated in its turn, and the contents of the retort brought into contact with water, the sodium bromide is dissolved out, while glyoxylide,

H202.
Fo202,2C204)

H2O2. H2O2.
2C2049

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130

Enamelled Cooking Vessels.

and there is nothing to hinder us from assuming that the
same compound is engendered by the action of the first
molecule of alcohol on the glyoxylate, while two mole-
cules of water are eliminated. The ether being now in
the presence of that element, which is capable of pro-
voking the series of molecular changes I have already
indicated, is speedily made to pass into the isomeric mo-
dification of the acid bibasic glyoxylate of ethyl,—
H2O2. Et2O2. H2O2.
F0202,2C2O4,

PROF. DITTMAR AND THE

CHEMICAL NEWS, Sept. 22, 1876.

"ANALYST."

PERHAPS some of our readers may have seen in the official organ of the Society of Public Analysts, along with other startling matter, a report of the prosecution of a certain Mr. McKinnon, of Glasgow, for selling adulterated butter, and a leading article commenting in very severe terms upon the evidence of Prof. Dittmar, who was a witness on 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,

H2O2. 2(Et2O2). F0202, 2C2O4,

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but, whichever way we take it, it becomes certain that the end product of this lengthy and complicated reaction must be the triatomic ethyl-glyoxylate of diethyl, as formulated above.

From the preceding explanations the reader will no longer be at a loss to comprehend the true cause of the hitherto unaccountable appearance of acidity on the part of the ammonium glyoxylate while it is being evaporated, -a discrepancy which Mr. Perkin would fain attribute to a want of stability and to its not possessing the character of a true salt, but which is really due to the different positions a particular molecule of hydrogen is destined to occupy in the system, and to the different duties and functions it is thereby made to discharge. Accordingly the neutral or a modification will require to be represented by the formula

H2O2. Am2O2. F0202,2F005,

and the acid or modification by the formula

H2O2. Am2O2. H2O2. F0202, 2C2O4)

and the same constitutional differences will be traceable in their respective amides, the a glyoxylamide being expressed by the formula

H202.

Fo202,2F004-2H2N2,

and the ẞ glyoxylamide by the formula

H2O2. H2O2.
Fo2O2,2C2O3-2H2N2.

sent by Prof. Dittmar to the Glasgow Herald the report in the Analyst seems by no means accurate. He did not pronounce the butter "quite sound," but declared that it was "more likely than not to be contaminated with foreign fat," though he did not feel free to swear to the presence of this impurity. He did not, from any evidence to which we have access, "deliberately prefer old and worthless methods," but merely expressed a doubt-not, in our humble opinion, quite unpardonable-whether the method of Dr. Muter had as yet been verified by a sufficiently wide experience. In short, it would appear that our contemporary's report goes beyond the facts of the case, and that his leading article goes no less decidedly beyond the report.

We know that there are in connection with the Analyst chemists of well-earned reputation, equally anxious for the advance of their science and for the elevation of their profession. To these gentlemen at any rate, if not to the writer of the article in question, we would, in all courtesy, suggest that such attacks as that in the last number of the Analyst merely strengthen the hands of the common enemy-those, namely, who consider chemical analysis as altogether untrustworthy, and who regard chemists themselves as either "imbecile," "incompetent," or even as impostors."

44

ENAMELLED COOKING VESSELS.

Ar the country meeting of the Society of Public Analysts held in Glasgow, during the recent visit of the British Association, a paper was read by Mr. Robert R. Tatlock, F.R.S.E., F.C.S., Glasgow, on "Enamelled Cooking Vessels." He stated that in some instances the milkwhite porcelainous enamel, with which cast-iron cooking vessels are now so commonly prepared, is of such a character as to be objectionable in the highest degree on account of the easy action upon it of acid fruits, common 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

Am202. 2C2O2,2F003,

and which at all events must be regarded as a true ammonium-salt, I can only regret that this interesting compound has not yet received that amount of attention which it assuredly deserves.

In drawing to a close, I may yet be permitted to express an anxious hope that our leading experimentalists may soon condescend to re-investigate this and other kindred problems on the principles and in the spirit of my "Typo-Nucleus" theory,-a task for which these gentlemen are so well qualified, not only in virtue of their superior talents and their exalted professional position, but more particularly on account of the rare practical tact and experience which enables them to cope with the many difficulties that are sure to be encountered in this department of organic chemistry.

ERRATA.-P. 121, line 10 from bottom, for "glyoxalate" read "glyoxylate." Line 14 from bottom, for "bromoglyoxylate" read "bromoglyoxalate."

quantity during cooking operations. The following analyses were given of three enamels, the samples having been taken from three cast-iron pots made by different manufacturers:

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CHEMICAL NEWS,

Sep. 22, 1876.

Anthrapurpurin and Flavo-Purpurin.

The author shewed that it was not so much on account of the presence of large proportions of lead and arsenic that the enamels are so objectionable, but because they are so highly basic in their character that they are readily acted upon by feebly acid solutions, the lead and arsenic being thereby easily dissolved out. He showed that the ratio of the bases to the silica in the No. I was as I to 158; in the No. 2 as I to o'79; and in the No. 3 as I to 0.76. A 1 per cent solution of citric acid boiled in the No. I did not affect it in the slightest, while in the case of the No. 3 the glassy surface of the enamel was at once roughened and destroyed, and lead dissolved out to such an extent as to give immediately a dense black precipitate with sulphuretted hydrogen. He thought that no enamel should be admitted to use unless it was totally unaffected by boiling with a 1 per cent solution of citric acid, which was a very moderate test, and gave it as his opinion that either the use of such poisonous ingredients as lead and arsenic in large quantity should be entirely discontinued, or that the composition otherwise should be of such a character as to ensure that none of the poisonous substances could be dissolved out in the circumstances under which the vessels are used.

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IN a former communication we described certain substitution-products of isoanthraflavic acid and anthraflavic acid, to show the difference of these two bodies also in their derivatives. We now describe certain experiments made to ascertain the part which these substances play in the manufacture of alizarin. We may ask how they are formed; whether they pass into alizarin on prolonged reaction with alkali; or, as seems most probable, whether they yield oxidation-products, and consequently purpurins?

We have ascertained that each of the acids yields a purpurin, isoanthraflavic acid forming the anthrapurpurin described by Perkin and anthraflavic acid-a new compound, which we have provisionally named flavopurpurin. The statement of one of us that anthraflavic acid is converted into alizarin on fusion with alkali must therefore be corrected.*

Action of Hydrate of Potassa upon Isoanthraflavic Acid. -If the aqueous solution of the potassic salt of this acid is heated with caustic potassa the originally red colour passes gradually into a violet, and particularly quickly when the temperature approaches the melting-point of potassa. When the intensity of the violet no longer increases the operation is interrupted, the melt dissolved in water and supersaturated with hydrochloric acid. A yellow gelatinous precipitate falls, which is treated with cold baryta water to remove some undecomposed isoanthraflavic acid. The residual lake, on decomposition with hydrochloric acid, yields pure anthrapurpurin, which can be readily obtained in long orange needles by crystallisa

tion from alcohol.

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131

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Readily soluble in boiling

alcohol. Sparingly soluble in boiling water.

Solution becomes red on prolonged boiling.

Sparingly soluble in ether. Soluble in boiling glacial acetic acid, and crystallises on cooling in stellar groups of needles.

Soluble in concentrated

Flavo-purpurin.

needles.

Readily soluble in cold

alcohol.

Sparingly soluble.

Solution remains yellow.

Ditto. Ditto.

Soluble in concentrated

sulphuric acid with a red- sulphuric acid with a reddish

violet colour.

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Alcoholic lead acetate

gives a purple precipitate which dissolves with a violet colour on boiling with excess of the precipitant.

gives a fine violet solution. Alcoholic copper acetate Sparingly soluble in alum. Melting-point above 330°. Sublimes in orange needles.

Dyes with mordants. Alkaline solution gives two absorption-bands having the same position as those

of alizarin.

brown colour.

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To ascertain whether the above-described reactions might not be modified by small quantities of impurities, we converted both the purpurins into acetyl compounds, re-crystallised them until the melting-point became con

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