Rodolfo Amedeo Lanciani.

The American journal of science and arts online

. (page 38 of 109)
Online LibraryRodolfo Amedeo LancianiThe American journal of science and arts → online text (page 38 of 109)
Font size
QR-code for this ebook


acid solution. According to calculation it should have been
2*6 cc In order to prove that acetate of potassium had really
been formed, the neutralized solution was evaporated on a
water-bath, and the dry residue was treated with absolute
alcohol Acetate of potassium was dissolved by the alcohol,
and could be easily recognized on evaporating the solution.

The other product formed during the saponification must be
an alcohol of silicic ethyd containmg the same radical as the
above mentioned acetic ether, and, on repeating the experiment
with a considerable quantity of substance, we succeeded with-
out difficulty, on treating with water the alcoholic solution after
saponification, in obtainmg such a compound. The alcohol of
silicic ethyd is a liquid lighter than water, and insoluble in it,
and boiling at about 190®. Its formula is SiCgHuOH.

L Substance inc(mpktely purified distilled 185®-190®. Substance
=0-1477 grms. ; (7O,=0*8200 grms. ; 5iO=0*1667 grms.

n. Purified substance boUing 185® - 195®— /SW«<ance= 0*2100
grms. ; CO2=0*4600 grms. ; -ff,O=0*2S55 grms.

ILL Same substance=0'ld70 grms. ; (70a=0*4S20 grms. ; H^O-
0*2210 grms.

L n. m. Calculated for SiaHisOH

0=59*08 69*74 59*80 60O0

H=12*54 12*46 12*46 12*50

The properties of this body, so fer as we have studied them,
are entirely similar to those of the alcohols of the ordinary
series, which contain a large number of atoms of carbon.

We have already shown that it forms an ether with acetic
acid; it also forms an alcoholate of sodium, dissolving that
metal with disengagement of hydrogen to form a gelatinous
mass, which regenerates the alcohol and gives a solution of
caustic soda, when it is treated with water.



. Digitized by VjOOQ IC



Silicon tviih Alcoholic Radicals. 82S

It is apparent, from the facts above cited, that, in a certain
class of reactions, the group of atoms, SiCgHn, remains intact,
and plays the part of a compound radical, in fiie same way that
the ordinary alcoholic radicals, like ethyl, (QjHs), and amyl,
(C5H11), remain imdecomposed in the same class of reactiona
The new body, in its relations to many reagents, is simply a
new hydrocarbon, with silicon substituted for a portion of the
carbon.

It is most remarkable that the presence of silicon in the
hydrocarbon modifies its properties to so slight a degree : id fact
wo have considered silicic ethyd as belonging to the same class
of bodies as the petroleum oils, and have applied to it the same
methods of study which have been used so successfully by
Pflouze and Cahours* in treating the American petroleums,
and have obtained similar residts. The want of the necessary
material has prevented us from completing the study of the
alcohol, but we hope to take up the research again.

We may embody this idea of the theory of the constitution of
silicic ethyd, and recall its analogy with a well known class of
hydrocarbons, by naming it the hyarid of sHico-nonyl, The alco-
hol is sUt'co-nonylic alcohol containing the radical silico-nonyl
(SiCgHi,)

Hydnd of nonyl, (CjHao), of which the sihcic compound may
be r^arded as a pioauct of substitution of silicon for one atom
of canx>n, shoidd be obtained by the action of zinc-ethyd on the
chlorid of carbon— CCI4 + 2Zn(CaH6),=2ZnCl, + [C(C^5)4 =
OgHao], and we have made some experiments with a view to pre-
paring it in this way. Thus fer, however, we have fidled to
obtain the reaction with chlorid of carbon and zinc ethyl alone,
and also with zinc ethyl to which sodium has been added.

Friedel and Ladenburgf have obtained a hydrocarbon by the
action of zinc ethyd upon methyl-chloracetiS, whose composi-
tion is represented by the formula C(CH8)s(CjH5)a, and wnich
must be regarded as analogous in constitution and mode of
formation with the body, wnich we sought to obtain fr^m the
chlorid of carbon, so that the production of the latter may be
considered as probabla

We have noticed, while studying the bromated products of
substitution of silicic ethyd, that in them the residue SiCsHu
combined with the bromine does not act like an alcoholic radi-
cal, but that, when they are brought in contact vrith acetate of
potassium^ or with caustic potash, the atom of ethyl containing
the bromine is separated from it and replaced by oxygen, to
form the oxyd of silicic triethyd ; the same is true of the chlo-
rated compounds, which contain more than a single atom of

* Oomptet Bendus de PAcad^mie des SoienooB, !▼{, p. 665, 1863.
f Oomptes Rendus de I'Acad^mio des Sdenoes, bdU, p. 1083, and Bulletin de
la bodM Chimique, [2], yii, p. 65.



Digitized by VjOOQ IC



824 Fnedd and Crofts en the combinations of

chlorine, and here the presence of silicon reveals itself in the
hydrocarbon, determining a point of weaker cohesion, which
r^ults in the rupture of the union between itself and the carbon
of the atom of ethyl containing the chlorine. In these last men-
tioned reactions, therefore, an analogy is apparent between
silicic ethyd, and the other known compounds of organic radi-
cals with metals.

The chlorated silicic ethyd, whose boiling point was 210®-
220°, was experimented upon, and the body was heated with an
excess of acetate of potassium in alcoholic solution. On open-
ing the tubes we found that the same gas was given on in
greater abundance, whose production we have alreisuiy noticed
5om the higher chlorated compounds which approach the mono-
chlorated compound more nearly in their composition. In one
operation we observed that the cas, which was first evolved,
contained chlorine, and could be absorbed by bromine ; this was
not the case with the gas given off afterwaroa

In another operation, in order to obtain a clue to the reaction,
we passed the cas into a solution of subchlorid of copper in
ammonia, and men into bromine. A small quantity of the
cupric compound of acetylene and of the bromid of ethylene, or
of chlorated ethylene, was formed.

The principal product of the reaction was the same oxyd of
silicic triethyd, which was produced by the action of acetate of
potassium on tiie bromated silicic ethyd.

This product was treated as before, with sulphuric acid to
purify it, and the following analysis was made of it :

L Sub8tance=^0'2210 grms. ; (7O,=04745 grms. ; 5;O=0-2480
grms.

L ClcuIatedforOJH^^);

0=58-55 58-53

H=12-S6 12-19

It is possible that the formation of this compound may be
represented by the equation :

2Si(CH,),C,H,Cl,+2KC,H,0,=2KCl+0(C,H,0),+



2CACi+o{|gg;j;



The formation of acetylene may be due to the action of chlo-
rated ethylene upon the acetate of potassium, according to the
equation :

CACl+K C,H,0,=HC3|H,0a+KCl+C!aH»

This interpretation of the reaction can not be considered as
established without further verification ; but one fact is unques-
tionable, and appears to us very important, namely : that it is an
atom of ethyl containing two or more atoms of cnlorine, which



Digitized by VjOOQ IC



SSdeon unih Alcoholic RadiccbU. 826

separates from the silicic ethyd to ^ve rise to the oxyd, and
consequentlv the continued substitution of chlorine for hydro-
gen takes place in an atom of ethyl already containing chlorine,
and not as might have been expected in an atom of emyl, which
contained no chlorine already. The fiict is contrary to our
usual ideas, founded upon the electro-chemical theory m regard
to chemical affinity, and its significance in the study of organic
radicals is easily appreciated. According to the theory, a group
of atoms, alreaay containing chlorine, should be less inclined to
receive a ftirther amount, and the substitution should take place
by preference in the atoms of ethyl which are free from chlorine.
The observation which we have made is not without analogy,
for Lieben* has shown that, in the action of chlorine upon
ordinary ether, the substitution of two atoms of chlorine
takes place in one of the atoms of ethyl to form the body,

c!h * [ ^» while the other atom of ethyl remains unacted

upon, it is remarkable that this analogy should exist between
ether and silicic ethyd, a body resembling a hydrocarbon so
much more clearly than ether does.

OXYDATION OF SiLICIC EtHYD.

We have already stated that silicic ethyd is a very stable
compound, and that in order to oxydize it completely with
strong nitric acid or with a mixture of chlorhydnc acid and
chlorate of potassium, it is necessary to operate at a tempera-
ture of 180 . We endeavored to obtain a partial oxydation
by heating with fuming nitric acid at a lower temperature, and
for this purpose an apparatus was made entirely of glass, in which
the sihcic ethyd was coiled with the nitric acid, and the vapors
were condensed and made to flow back into the vessel which
was heated. After prolonged ebullition, during which nitrous
fumes were given off; the product was washed with water and
treated with ether, in which it was in great part solubla On
evaporating the etheric solution a viscous liquid was obtained,
which could not be distilled, but which was dried in vacuo over
sulphuric acid and analyzed.

L Suh8tance=^0-221b grms. ; COi=0'S880 grms. ; E^O^O^OIO

orTYis.
n. &ub8tance=Q'i20b grrm. ; SiOi=0'1960 grms.

L n. Calculated for Si0(CaH.),

0=46-51 .... 47-05

H= 9-81 .... 9-80

Si=.-.. 28-53 27-45

* Bulletin de la Sod^t^ Ohiraique, n, viil, p. 429, and Aiinalen der Chem. und
Pharm., oxli, p. 236.



Digitized by VjOOQIC



826 Friedd and Orafis en the (xmMnations of

These numbers accord ver^ neariy with those req^iired by
the composition of an oxyd SiO(CaH!5)2 in which two atoms of
of ethyl are replaced by one atom of oxygen, and the body
would be the next more advanced product of oxydation to
the oxyd of silicic triethyd, but, as we have not made sufl&cient
experiments to determine the chemical properties of this sub-
stance, we are unable to form a decided opmion as to its true
nature.

Silicic Methyb.

We first attempted to j)repare silicic methyd bv means of
mercuric methyd and chlorid of silicon. The two bodies were
heated together in a sealed tube for 15 hours at 180°-200® ;
lamellar crystals of mercuric chlorid and methyd (HcCjHjCl)
were formed, and a gas which was not absorbable by bromine
was given off on opening the tube. The liquid contents of the
tube were distilled with caustic potash in order to destroy the
chlorid of silicon, and were found to consist chiefly of unde-
composed mercuric methyd together with a small quantity of a
more volatile body, which seemed to be silicic methvd. This
mode of preparation not being advantageous, we had recourse
to zinc methyd in the next operation.

The mercuric methyd was transformed into zinc methyd by
the process given by Frankland, and the latter was heated with
an excess of silicic chlorid for several hours at 200®. A
reaction commences at 180°, but a temperature of 200® is neces-
sary to render it complete. The tube contained chlorid of zinc
as a white powder, and we were able to obtain fix)m it by dis-
tillation a volatile liquid, which, after having been washed with
a solution of caustic potash, had the same properties as the
silicic methyd obtained with mercuric methyd.

The preparation of zinc methvd by means of the mercuric
methyd is tedious and disagreeaole, and we therefore preferred
to obtain it by the. action of zinc upon the iodid of methyl, a
method which has been already employed by Butierow* on a
small scala Instead of the glass tubes which he employed, we
used Frankland's digester, in which we heated zinc-turnings at
120® with iodid of methyl, taking the precaution to interrupt
the operation fix)m time to time in order to cool the digester
with ice-water, and to open it to allow the escape of the gasesf
which form in large quantity. We obtained in this manner,

« Bulletin de la Sod^t^ Chimique, t, p. 682.

f Notwithstanding Mr. ButIerow*8 assertion (Annalen der Chem. und Phann^
czUt, p. 39), that the dnc methyl gases are not poisonoue^ one of us has repeatedly
experienced ill effects from breathhig them, and it is advisable to set them on fire
as they issue from the digester. It is possible that the difference between our own
observations and those of Mr. Butierow may be due to impurities in the one or to
the fact that we used a copper digester.



Digitized by VjOOQ IC



Silicon with AlcohoHc RadicaU. 827

by distilliiig directlj from the digester, zinc meth jd, which still
contained a little iodid of methyl This product was treated
m the digester with zinc turnings and chlorid of silicon, after
we had assured ourselves that dilorid of silicon does not act
upon metallic zinc at the temperature employed, but only
upon the zinc methyd which is formed from it indeed chlorid
of silicon is not decomposed even by sodium except at a high
temperature.

In order to allow the zinc to act upon the small quantity of
iodid of methyl contained in the zinc methyd, the digester
was first heatea for 12 hours at 120°, and then for 10 hours at
200** to eflfect the reaction between the chlorid of silicon and
the zinc methyd. The digester was cooled with ice before it
was opened. After the escape of the gas the product was dis-
tilled into recipients cooled with ice, and then treated at 0°
with a solution of caustic potash in order to destroy any excess
of chlorid of silicon which might be present It is important
to employ nearly equivalent quantities of zinc methyd and of
sihcic cmorid, because the heat which is developed by the
action of the caustic potash upon the excess of either occasions
a loss of the silicic methyd.

Silicic methyd obtained by this process is a clear transparent
U^uid, lighter than water and boiling at 80^-81**. It bums
with a luminous flame and a smoke of silicic acid. The follow-
ing analyses were made of this substance :

L Substance=^0'l^5 grms. ; OO,=0-8660 grms. ; ^,0=0-2275
grms.

The substance was burnt too quickly in the first analysis
and a loss of carbonic acid was occasioncKi.

n. Sub8ta7ic€==0'1940 grms. ; COi=0'S875 grms. ; ^aO=0-2850
grms.

L n. Calculated for 8i(CH8)4

0=58-81 5447 6454

H=18-68 18-46 18-68

The determination of silicon in this substance presents un-
usual difficulties, on account of its great stability in contact
with oxydizing agents and its volatility. We employed the
method, which was used for the silicic ethyd, but nere it is
necessary to enclose the substance in a bulb which is broken
after sealing the tube. (Silicic ethyd boils at so high a tempera-
ture, that it can be weighed in a lon^ narrow tube with a cork).
Fuming nitric acid was the oxydizing agent used, and the
silicic methyd was heated with it for two days at 200*^, but was
found on opening the tube not to be completely decomposed.
In a second determination we used a very large excess of fiim-



Digitized by VjOOQ IC



828 Friedel and Orafis on the oomMnations of

ing nitric acid and heated for forty hours at 250^-800° and
obtained the following result :

ASMi5toncc=0-2330 grms. ; /Si*Oa=01405 grma.
Si= 29-85 p. c. calculated=81-81.

It is diflBcult to remove the silicic acid completely from the
tube by a treatment with caustic potash, and either there was a
loss in manipulation, or the silicic methyd was not completely
decomposed even at 800°.

Two other determinations made at a still higher temperature
were lost from the bursting of the tubes.

The above analyses leave no doubt that the composition of
silicic methyd is represented by the formula : Si(CH8)4, and this
result is completely in accordance with the vapor density deter-
mination maae by Gay Lussac's method.

Substance employ€d=0'181S grms.

Temperature of the bath 100°.

Height of the barometer 751*7 m^m. at 8°.

Volume occupied by the vapor 85 c.c

Height of the m>ercury in the measuring tube 194 m.m.
Vapor density by experiment =8*058

Vapor density by calculation =8*045

If the silicic ethyd represents the hydrid of silico-nonyl, the
silicic methyd is the hydrid of silicopentyl, SiC^Hj,, or the
silicated substitution product of the hydrocarbon of the amylic
alcohol series.

The want of material has prevented us from carrying the
study of this bod j farther ; we will only call attention to the
great difference m the boiling points of theses homologous
silicated hydrocarbona

Silicic ethyd boils at 152° '5 oentigrada
Silicic methyd " 80°* "

Difference = 122°*5 "

This difference corresponds to 80° '5 for each increment of
CH, and is quite at variance with Kopp*s law. This fiict is the
more remarkable since we have shown that in the homologous
silicic ethers of the normal series, the difference of boiling-point
corresponding to an increment of CHf is 11° and in the msilicic
ethers it is only 5°.

Silicic Ethyd and Methyd.

It is obvious that considerable interest attaches to the com-

Eletion of the series of the silicated hydrocarbons, of which we
ave described the members corresponding to the pentyl and
the nonyl group, and it appears probable that all the inter-



Digitized by VjOOQ IC



Silicon with Alcoholic Radicals, 82 9

mediate ones may be obtained by the simultaneous action of
zinc methyd and zinc ethyd, in diflferent proportions upon the
chlorid of silicon ; we have not yet, however, oeen able to make
any extended researches in tms direction, but will give the
result of a single experiment conducted on a small scala

In order to prepare a mixture of zinc methyd and zinc ethyd,
we heated in tne digester for 24 hours at 100°, a mixture of
iodid of methyl and of iodid of ethyl with zinc turnings.
The liquid after distillation was found to contain iodine, and it
was reheated for 48 hours with the pulverized alloy of zinc
and sodium and vnth zinc turnings ; we thus obtained 85 grms.
of a product, whose boiling-point was lower than that of zinc
ethyi To this product 8 mna of zinc methyd were added
and 85 grms. of the chlorid of silicon, and the whole was
heated for seven hours at 195^ The resulting product was
distilled, washed vdth a solution of caustic potash, and
treated with strong sulphuric acid, 10 grms. of a liquid, in-
soluble in sulphuric acid were obtained, and were submitted
to a fractional distillation. The greater part passed at 68^-67**.
This portion was analyzed.

L >SMi5toncc= 01776 grms.; (7O,=0-4240 grms.; 5;0=0-2284
grms.

Si(CH8) (CjHb), 8KCH8> (C,Ha),

0=6511 64-61 61-20

H=14-28 13-84 18-79

It would appear from the analysis that this body is silicic
methyd-tri-etnyd nearly pure, but its low boOing-pomt renders
this highly improbable, and it is possible that the high per-
centage of carbon and hydrogen may be due to the presence of
some saturated hydrocarbon. According to its boilmg-point it
should be silicic tri-methyd ethyd, but we had not a sufficient

Juantily of material to make further experiments in< order to
etermme its true composition. It is certain that the body
was neither silicic methyd nor silicic ethyd but an interme-
diate product

The bodies studied in this research belong to the same type
as chlorid of silicon.

Chlorid of silicon, SiC^

Silicic ethyd,

Chlorated silicic ethyd or chlorid of

Acetate of silico-nonyl, .

Silico-nonylic alcohol,

Dichlorated silicic ethyd.

Except the oxyd which has a strong tendency to form in so
many reactions, and which belongs to a diflferent type : namely.



Digitized by VjOOQIC



Friedel and Orafia on the ccnnbinations, etc

to one in which two groups of molecules are linked together
through the medium of oxygen. It may be referred to the
same type as the disUicic etners.

DisiKcic hexethyUc ether, j licjHlo jj

Oxyd of sihcic tri-ethyd, O j ||!c j^jj

The oxychlorid of silicon, | qIqI*

belongs also to the same type.

In some of these compounds the chlorine is represented aa
combined with carbon in the place of hydrogen, and in others
as combined directly with silicon. The difference in formulas
is justified by the marked difference in properties which the
chlorine exhibits in the two kinds of combination.

Compounds containing chlorine combined directiy with sili-
con are readily decomposed by water with formation of chlorhy-
drio acid ; while the chlorine m the other class of compounos
displays the same inertness, which characterizes it in nydro-
caroons, and is not acted upon by water, Itnd only at a very
high temperature by acetate of silver. Exactly the same dif-
ference of properties obtains for the radical of acetic acid con-
tained in the acetins of silicic ether, where it is in direct com-
bination with the silicon, and the same radical contained in the
acetate of silico-nonyl, where it is in combination with carbon.

Only one point remains in which the analogy between silicon
and carbon is incomplete. "We have said that the most charac-
teristic property of carbon in organic bodies is its power of
combining directljr with itself to form a complex molecule,
capable of combining still ferther vrith other elements, as when
two atoms of carbon, C|, combine with six atoms of hydrogen
to form the hydrid of ethyl, C,H«. All the bodies thus fiur
discussed belonff to the simplest type of carbon compounds, as
CH4 and its analogue SiH^ ; and m silicic ethyd 4 times CJEE,
occupy the place of H4 ; but Friedel and Landenburg* have
lately completed the analogy and obtained the bodv, Sij(CtH5)e,
belonging to the same t^pe as Si^H^ and CgHe, showing that
even in its quality of forming condensed compounds silicon
resembles carbon.

* Oomptes Bendas de TAcad^ie des Sdences, Izriii, p. 920, 1869.



Digitized by VjOOQIC



J. L. SnvUk on the Franklm oomkty Meieoric Iron. 881



Abt. XXXHL — Description and Analysis of (he Franklin County
Meteoric Iron; with remarks on the presence of Copper arid
Nickel in meteoric irons ; the method ofanodyring the same; and
the probability of the Lead in the Tarapaca iron having been orig-
inculy foreign to thai mass ; by J. Lawbbncb Smith, Louis-
ville, Ky.

1. 77ie Franklin County Meteoric Iron.

The Franklin County meteoric iron was first brought to my
attention in a blacksmith shop in Frankfort, Kentucli^. It was
carried there to be tested in regard to its (jualily as iron ; being
supposed by its discoverer to indicate an iron mina Mr. Nel-
son Alley became possessed of it, and kindly presented it to ma

It came from a nill eight miles southwest of Frankfort, lat
88° 14', long. 80'' 40' (Greenwich), and was discovered in 1866.
It passed into my possession in 1867, and was then described by
me, but the manuscript was lost after its leaving my hands, and
the original notes were displaced ; the notes have been recently
discovered and the iron agam analyzed

Its form is somewhat globular, with a highly crystalline
structura Its weight was twenty-four pounds, and tlus appears
to have been its original weight, only a few flakes having be-
come detached by the rusting through of some of the fissures
— sp. grav. 7-692.

Its composition when perfectly fireed from rust and earth is

Iron, 90-58

Nickel, 8-68

Cobalt, 0-8tt

Copper, minute quantity

Phosphorus, 0*06

99-52

Having, as it will be seen, the usual composition of meteoric
irona
While on the subject of this iron, I will add some remarks.

2. On the presence of Cobalt in Meteoric Irons.

My attention has been directed again and again to meteoric
irons, whose analyses are given without mention of the presence
of cobalt, and in some instances, with the distinct statement that
it is absent, as in the recent examination of a meteoric iron from
Auburn, Macon county, Alabama, by Professor Shepard, who
states that " neither cobalt, tin nor copper was detected in this
iron.'' I cannot but suggest the importance of making a most
critical examination of these irons before pronouncing this fact;
for in every analysis that I have made of meteoric irons, (over



Digitized by VjOOQ IC



882 J. L. Smith on the analysis of Meteoric Irons.

one hundred diflferent specimens), with this in view, cobalt has
been invariably found, along witn a minute quantity of ooppOT.
A great many of the analyses made were of irons that had oeen
previously examined without a recognition of the cobalt

The presence of these ingredients, even in small quantities, is
a matter of considerable mineralogical interest, as is the case of
the presence of small quantities of other elements in many min-
erals ; a fact that I will have occasion to refer to at some future
time, in connection with leucite and other silicates.

As a guide to those who may wish to know the manner of
my examination of meteoric iron, I will give a little in detail the
method adopted in separating the metala



Online LibraryRodolfo Amedeo LancianiThe American journal of science and arts → online text (page 38 of 109)