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Scientific American Supplement, No. 841, February 13, 1892 online

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by partial boiling the insoluble particles engrained in the cloths.
This has been found to make the cloths last longer. This cloth is
obtained from Porritt Bros. and Austen, Stubbing Vale, Ramsbottom, and
costs 13½d. per lineal yard of a width to suit the disks.

The quantity softened is 2¼ million gallons per 24 hours, but the
present plant can deal with 2½ million gallons, and the buildings are
erected for 3½ million gallons, additional filters and lime producing
tanks being only required to deal with the increased quantity. The
costs of the softening works was £10,394, of which £7,844 was for the
softening machinery and plant and £2,550 for the reservoir, buildings,
etc.

The working expenses, including lime, labor, cloths, general repairs,
and steam, is stated to be 0.225d. per 1,000 gallons, the labor
required being only two men, one on the day and the other on the night
shift, with an occasional man to assist.

The hardness of the Southampton water on Clark's scale is 18° of total
hardness, and this is reduced down to 6° or 8° by this process. - _Chem.
Tr. Jour._

* * * * *




A NEW LABORATORY PROCESS FOR PREPARING HYDROBROMIC ACID.

By G.S. NEWTH.


This method is a synthetical one, and consists in passing a stream of
hydrogen and bromine vapor over a spiral of platinum wire heated to
bright redness by means of an electric current. A glass tube, about 7
inches long and 5/8 of an inch bore, is fitted at each end with a cork
carrying a short straight piece of small tube; through each cork is
also fixed a stout wire, and these two wires are joined by means of a
short spiral of platinum wire, the spiral being about 1 inch long. One
end of this apparatus is connected to a small wash bottle containing
bromine, through which a stream of hydrogen can be bubbled. The other
end is attached to a tube dipping into a vessel of water for the
absorption of the gas, or, if a large quantity of the solution is
required, to a series of Woulf's bottles containing water. Hydrogen is
first slowly passed through the tube until the air is displaced, when
the platinum spiral is heated to bright redness by the passage of a
suitable electric current. Complete combination takes place in contact
with the hot wire, and the color imparted to the ingoing gases by the
bromine vapor is entirely removed, and the contents of the tube beyond
the platinum are perfectly colorless. The vessel containing the
bromine may be heated to a temperature of about 60° C. in a water
bath, at which temperature the hydrogen will be mixed with nearly the
requisite amount of bromine to combine with the whole of it. So long
as even a slight excess of hydrogen is passing, which is readily seen
by the escape of bubbles through the water in the absorbing vessels,
the issuing hydrobromic acid will remain perfectly colorless, and
therefore free from bromine; so that it is not necessary to adopt any
of the usual methods for scrubbing the gas through vessels containing
phosphorus. When the operation is proceeding very rapidly a lambent
flame occasionally appears in the tube just before the platinum wire,
but this flame is never propagated back through the narrow tube into
the bromine bottle. The precaution may be taken, however, of plugging
this narrow tube with a little glass wool, which renders any
inconvenience from this cause quite impossible. By this method a large
quantity of bromine may be rapidly converted into hydrobromic acid
without any loss of bromine, and the operation when once started can
be allowed to proceed without any further attention. - _Chemical News._

* * * * *




SAPOTIN: A NEW GLUCOSIDE.

By GUSTAVE MICHAUD.


_Achras Sapota, L._, is a large tree scattered through the forests of
Central America and the West Indies; its fruit is often seen upon the
Creole dinner table. This fruit is a berry, the size of an orange, the
taste of which suggests the flavor of melon, as well as that of
hydrocyanic acid. The fruit contains one or two seeds like large
chestnuts, which, if broken, let fall a white almond. This last
contains the glucoside which I call _sapotin_.

I obtained sapotin for the first time by heating dry raspings of the
almond with 90 per cent. alcohol. While cooling, the filtered liquid
deposited a good deal of the compound. Since that time I have
advantageously modified the process and increased the amount of
product. I prepare sapotin in the following way: The almonds are
rasped, dried at 100° C. and washed with benzene, which takes away an
enormous quantity of fatty matter. The benzene which remains in the
almond is driven put first by compression, afterward by heating. Then
the raspings are exhausted with boiling 90 per cent. alcohol. The
solution is filtered as rapidly as possible, in order to avoid its
cooling and depositing the sapotin in the filter. As soon as the
temperature of the filtered liquid begins to fall, a voluminous
precipitate is seen to form, which is the sapotin.

In order to purify it, the precipitate is collected in a filter and
expressed between sheets of filter paper. When dry it is washed with
ether, which takes away the last particles of fatty and resinous
matter. The purification is completed by two crystallizations from 90
per cent. alcohol. At last the substance is dried at 100°.

The sapotin separates from its alcohol solution in the form of
microscopic crystals. When dry, it is a white, inodorous powder. Its
taste is extremely acrid and burning. If the powder penetrate into the
nostrils or the eyes, it produces a persistent burning sensation which
brings about sneezing and flow of tears. It melts at 240° C., growing
brown at the same time.

It has a laevo-rotatory power of [a]_{j} = -32.11, which was
determined with an alcoholic solution, the aqueous solution not being
sufficiently transparent.

It is very soluble in water, easily soluble in boiling alcohol, much
less in cold alcohol, and insoluble in ether, chloroform and benzene.
Its alcoholic solution is precipitated by ether.

Tannin has no action on it, but basic acetate of lead produces a
gelatinous precipitate in its aqueous solution. Strange enough, this
precipitate is entirely soluble in a small excess of basic acetate of
lead. If thrown into concentrated sulphuric acid, sapotin colors it
with a garnet red tint. It does not reduce Fehling's solution. Its
analysis gave the following results:

Calculated for Found.
C_{29}H_{52}O_{20}. I. II.

C 48.33 48.69 48.31
H 7.23 7.33 7.45

When heated with water and a little sulphuric acid, sapotin is
decomposed and yields glucose and an insoluble matter which I call
_sapotiretin_. One hundred parts of sapotin produce 51.58 parts of
glucose and 49.67 of sapotiretin. The equation which represents this
reaction is:

C_{29}H_{52}O_{20} + 2H_{2}O = 2C_{6}H_{12}O_{6} + C_{17}H_{32}O_{10}

and requires 50 per cent. of glucose and 55 per cent. of sapotiretin.

Sapotiretin is an amorphous compound, insoluble in water, very soluble
in alcohol, less soluble in chloroform, insoluble in ether. Below is
the result of its analysis:

Calculated for Found.
C_{17}H_{32}O_{10}. I. II.

C 51.52 51.51 51.20
H 8.08 8.19 8.34

- _Amer. Chem. Jour._

* * * * *




DETECTION OF PEANUT OIL IN OLIVE OIL.


Holde, after a careful trial of the various processes for detecting
the above adulteration, gives the preference to Renard's, which he
describes as follows:

Ten grms. of the suspected oil, after being saponified, and the fatty
acids separated by hydrochloric acid, are dissolved in 90 per cent.
alcohol, and precipitated by sugar of lead. The oleate of lead is
separated by ether, and the residuum, consisting of palmitic and
arachic acids, is decomposed by hydrochloric acid. The fatty acids are
dissolved, with the aid of heat, in 50 c.c. of 90 per cent. alcohol.
The arachic acid which separates after cooling is filtered out and
washed, first with 90 per cent. and afterward with 70 per cent.
alcohol. It is then dissolved in hot alcohol, and the solution
evaporated in a weighed saucer. The weight of the residuum, after
taking into account the acid dissolved in the alcohol, equals the
whole amount of arachic acid contained in the oil; the melting point
of this residuum should be 70° to 71° C. With this process the author
has always been successful; but when the olive oil contains not more
than 5 to 10 per cent. of peanut oil, it is necessary to make the test
with 40 grms. of the former, otherwise the melting point of the
arachic acid cannot be estimated. Furthermore, the acids which are
separated from the lead salt by hydrochloric acid must be
recrystallized repeatedly with 90 per cent. alcohol, until the melting
point ceases to rise, in case the latter is not found to exceed 70° C.
at the first estimation. When peanut oil is present, the melting point
will always be above 70°. - _Chem. Zeit._

* * * * *




HYDROXYLAMINE.


Free hydroxylamine, NH_{2}OH, has been isolated by M. Lobry de Bruyn,
and a preliminary account of its mode of preparation and properties is
published by him in the current number of the _Recueil des travaux
chimiques des Pays-Bas_ (1891, 10, 101). The manner in which the free
base was obtained was briefly as follows. About a hundred grammes of
hydroxylamine hydrochloride, NH_{2}OH.HCl, were dissolved in six
hundred cubic centimeters of warm methyl alcohol. To this solution a
quantity of sodium dissolved in methyl alcohol was added, in such
proportion that the hydrochloride of hydroxylamine was present in
slight excess over and above that required to convert it to sodium
chloride. After deposition of the separated sodium chloride the
solution was decanted and filtered.

The greater portion of the methyl alcohol was next removed by
distillation under the reduced pressure of 160-200 mm. The remainder
was then treated with anhydrous ether, in order to completely
precipitate the last traces of dissolved sodium chloride. The liquid
eventually separated into two layers, an upper ethereal layer
containing about 5 per cent. of hydroxylamine, and a lower layer
containing over 50 per cent. of hydroxylamine, the remainder of the
methyl alcohol, and a little dissolved salt. By subjecting this lower
layer to fractional distillation under 60 mm. pressure, it was
separated into three fractions, of which the first contained 27 per
cent. of hydroxylamine, the second 60 per cent., and the third
crystallized in the ice-cooled receiver in long needles. This third
fraction consisted of free solid NH_{2}OH. Hydroxylamine as thus
isolated in the free state is a very hygroscopic substance, which
rapidly liquefies when exposed to air, owing to the absorption of
water.

The crystals melt at 33°, and the fused substance appears to possess
the capability of readily dissolving metallic salts. Sodium chloride
is very largely soluble in the liquid; powdered niter melts at once in
contact with it, and the two liquids then mix. Free hydroxylamine is
without odor. It is heavier than water. When rapidly heated upon
platinum foil it suddenly decomposes in a most violent manner, with
production of a large sheet of bright yellow flame. It is only very
slightly soluble in liquid carbon compounds, such as chloroform,
benzene, ether, acetic ether, and carbon bisulphide. The vapor attacks
corks, so that the solid requires to be preserved in glass-stoppered
bottles. The free base appears also to act upon cellulose, for, upon
placing a few drops of the melted substance upon filter paper, a
considerable amount of heat is evolved. The pure crystals are very
stable, the base in the free state appearing to possess much greater
stability than when dissolved in water. The instability of the
solution appears, however, to be influenced to a considerable extent
by the alkalinity of the glass of the containing vessel, for
concentrated solutions free from dissolved alkali are found to be
perfectly stable. Bromine and iodine react in a remarkable manner with
free hydroxylamine.

Crystals of iodine dissolve instantly in contact with it, with
evolution of a gas and considerable rise of temperature. Bromine
reacts with violence, a gas again being explosively evolved and
hydrobromic acid formed. The nature of the gas evolved is now
undergoing investigation. A letter from M. Lobry de Bruyn appears in
the number of the _Chemiker Zeitung_ for October 31, warning those who
may attempt to prepare free hydroxylamine by the above method that it
is a dangerously explosive substance when warmed to a temperature of
80°-100°. Upon warming a flask containing the free solid base upon a
water bath a most violent explosion occurs. A spontaneous
decomposition appears to set in about 80°, and even in open vessels
the explosion is very violent. Care must also be taken during the
fractional distillation of the concentrated solution in methyl alcohol
to cool the apparatus before changing the receiver, as if air is
admitted while the retort is heated the experiment ends with an
explosion. - _Nature_.

* * * * *


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Online LibraryVariousScientific American Supplement, No. 841, February 13, 1892 → online text (page 11 of 11)