Rodolfo Amedeo Lanciani.

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and the distillation continued as long as any silicic ethyd con-



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812 FHedd wnd Orafi» on the oombinoitions of

tinued to pass ov&r with the vapor; the apparatus was then
cleaned ana a new operation commenced. As an example of a
number of such operations, we may cite one series in which 769
grms. of zinc-ethyd and 480 grms. of chlorid of silicon were
employed. We obtained 225 grma of perfectly pure silicic-
ethyd-=-about half the theoretical quantity.

!ui order to understand the phase of the reaction, which
results in the formation of gaseous products, and of metallic
zinc, we examined the gases, which were given off on opening
the digester, by passing them through bromine, freeing the gas,
which was not absorbed, from the excess of bromine, and col-
lecting it over mercury. The quantity evolved in an operation
is very large, and there was no difficmty in using the first por-
tions of the gas to remove the air from the apparatus containing
bromine, and in collecting at the end a peiiectly pure sample
for analysis.

The analysis of the gas, which was not absorbed by bromine,
gave:

Volume of the gas - - - - = 5*17
Oxygen added' ... - 27*72

Oontraction 1310

OaT^Hmic add .... 10'26

JRemaining oxygen determined by deto-
nation vdth H ' ' ' 9'50

Conseauently two volumes of the gas contained 612 volumes
of H, ana 1*98 volumes of carbon vapor.
A second analysis gave :

Volume of gas . . - . = 6*66

Oxygen added - - - . 26*61

Contraction 17*30

Carbonic add ... - 1302

Remaining oocygen - - - - 2*94

Two volumes of the gas contained 6*36 volumes of H, and
1*96 volumes of carbon vapor.

The gas was the hydrid of ethyl C^H,, two volumes of which
contain six volumes of hydrogen and two volumes of carbon
vapor.

The bromid which was obtained by the absorption of a part
of the gas by bromine, after having been washed with a solution
of caustic potash, dried and distilled at 132^-134^, was tmalyzed
wiA the following result :

L Substance =0'S695 grms. ; AgBr=0'7S15 grms.

n. /SM&tonce= 0-2712 grms. ; CO^ =^0'1S30 grms. ; 5, 0=0*0608

grm>s.
m. Substa/nce=0'S26d grms. ;C 0^=^0-1600 grms.; S,O=^0<i690

grms.



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n.




13-86


13-42 12-76


247


2-85 2-12


• • • •


85-11



SiUcan vnih Alcoholic Badicak. 818



C • • • •

H

Br 8448

The body is consequently the bromid of ethylene, ^nd the
gases, which are fonn^ during the preparation of silicic ethyd,
are simply those which are known to arise from the decomposi-
tion by means of heat of zinc-ethyd.

The question suggests itself: are intermediate products, aris-
ing fix>m an incompete replacement of chlorine by ethyl in the
chlorid of silicon, also formed? Such products should have
the composition: Si(CyBt)sCl; Si(C,H5)aCl, ; Si(CaH5)a„ and
should boil at points intermediate between 152°, the boiling
point of silicic etnyd, and 42**, the boiling point of chlorid of sil-
icon. The question must be answered in the negative ; for after
a large number of fractionated distillations of the product
^obtained in an operation, where a considerable excess qf chlorid
of silicon was used, it could be separated almost completely
into chlorid of silicon and silicic ethyd, and no bodies appeared
with fixed boiliujg points between 42** and 152**. The small
quantity of liquid, which was eventually obtained, distilling
between these points, was treated with caustic potash, and gave
no more of a compound containing oxygen than was ordinarily
obtained in everv preparation of silicic ethyd, and whose mode
of formation is aescribed below.

We failed also to obtain intermediate compounds on heating
chlorid of silicon and silicic ethyd together m sealed tubes for
15 hours, at a temperature of 240^ The product could easily
be separated by repeated distillation into tne two bodies which
were originally mixed.

It appeared probable that silicic ethyd, and perhaps interme-
diate Dodies, might be formed by a process analagous to that
employed by Frankland and Duppa* to obtain boric-ethyd,
B(C3B!5)8, namely : by the action oi zmc-ethyd upon normal sili-
cic ether. We found, however, that the two bodies do not act
upon each other, even at a very high temperature ; indeed the
tenacity with which silicon retains its hold upon oxygen ren-
ders tms result not surprising.

A most interesting phase of the reaction between zinc-ethyd
and chlorid of silicon, is the one which gives rise to the forma-
tion of tiie body containing oxygen, which has been noticed
abova As has been already stated, concentrated sulphuric
acids frees the crude silicic ethyd from a small quantity of a
foreign body, which is soluble in the acid. This body separates
from the solution when the sulphuric acid is diluted with water,

* Annales de Ohimie et Phannacie, ozr, 319.



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814 Friedel and Orafla on the combinations of

and floats upon the surface of the solution. It bums with a
siliceous smoKC, has a disagreeable odor until it has been purified
by repeated distillations, and boils at about 285®. The product,
which was purified as far as possible by a number of distilla-
tions, was analyzed.

L jSub8tance=0'1861 grms. ; CO2=0-4090 grms. ; ^720=0-2068

grrns.
IL ITie product of another operation^ whose boiling point was 229®-

235®. /S^&Jtowce=0-2585 grms. ; (70a=0-6868 grms. ; H^O^

0-2856.



L


n.


Calculated for 0)||(§H.),

58-54
12-19


0=59-94
H=12-84


57-71
12-51



Only a small quantity of this body is produced in the prepa-
ration of considerable quantities of silicic ethyd, and we have
not succeeded in isolating it in a perfectly pure state during '
that preparation; its composition is, however, not doubtjfii^
and we were able to recognize its identity with the same oxyd,
which can be easily obtained and purified by a method described
below. This oxyd must be derived from the oxyd of zinc,
which is formed by the action of the air upon zinc-ethyd while^
charging the digester. Friedel and Ladenburg* have found
that firee and combined oxygen can be substituted for a part of
the chlorine in chlorid of silicon, with formation of the oxy-

chlorid, O ] sjQi • This oxychlorid is probably formed in the

digester fix)m the oxyd of zinc, and acts upon the zinc-ethyd to

form the oxyd \ gifcS v ''^^^^ analysis is given abova

This oxyd may oe considered as the ether of the radical silicic-

triethyd ] a: ( p]+^ > a^^d as analogous with the simplest eth^ of

t fyzx
the ordinary series, \ q^ , silicon replacing the carbon, and

ethyl the hydrogen. It is more difficult to decompose than the
ordinary ethers, and resists the action of many of the agents *
which remove radicals from common ether ; one of us, however,
has succeeded in obtaining a double decomposition by means of
the chlorid of acetyl ; but the study of the products of the reac-
tion is not yet completed.

Action op Bromine on Silicic Ethyd.

Nothing distinguishes silicic ethyd more completely from the
compounca hitherto obtained by the action of the chlorids of

* Gomptes Rendus de rAcad^mie des Sdenoes, Ixyi, 639.



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Silicon with Alcoholic Radicah. 815

the elements on zinc-ethyd, than the manner in which it acts
with bromine and chlorine ; thus fiur the only reaction known
for such bodies is that in which the union between the alcoholic
radical and the other element is severed, and the bromine or
chlorine takes the place of the alcoholic radical

The researches K>r instance, which have been made by several
chemists* on stannic-ethyd, show that the action of bromine
on that body is represented by the eauation ; Sn(CaH5)4+Bra=
Sn(C2EL)8Br-|-C)aH5Br. We expectea a precisely similar reac-
tion witn silicic ethyd, and were surprised to find that the ethyl
was held so strongly by the silicon, that it could not be re-
moved by bromine or by chlorine, and that the only action was
a substitution of the bromine or chlorine for hydrogen in the
orranic radical

Bromine does not attack pure silicic ethyd at the ordinary
temperature ; but when two atoms of bromine are heated in a
sealed tube with silicic ethyd for IJ hours at 140®, the color of
the bromine disappears completely, and on opening the tube a
large Quantity of bromhydric acid escapes, while not a trace of
bromia of ethyl can be obtained by heating the liquid. The
contents of the tube distil at 160° — ^260°, leaving a small quan-
tityof carbonized matter as a residua

We could not succeed in isolating a product with a constant
boiling point by fi-actionated distillation.

The portion of the liquid which distilled 280"*— 240** ap-
peared to have nearly the composition of the mono-bromated
compound, but, on redistilling, the portion which distilled at a
lower temperature, 220® — ^230®, was found to contain less
carbon and hydrogen, and there was an appearance of decom-
position during the distillation.

L Boiling-point =230^-240®. Substance =0-2990 grms. ; CO^-

0-4810 ^rww; Jya0=0-2400 omTW.
IL Aw7m^./xnn^=220®-230®. Suh8tance=0'Z2i5 gmia. ; CO^-

0'i920 grms; 3^0=0-2400 grms.
UL Same 8ub8ta7ice=0'6250 grms. ; AgBr=0'6051 grma.



1


n.


m


OalcuktedforSiOiHigRr.


C 48-8


41-30


••••


48-65


H 8-8


8-21




8-62


Br ....


. - •


84-S8


85-87



We suspected that the portion of the liquid having the highest
boiling point might contain a dibromated product, and, after
a distdmtion in vacuo, analyzed a body which distilled at
120^-140^

* FranUand, Annalen der Ohem. und I^nn., Izxxr, p. 329 ; ozi, p. 44. Bnckton,
ibid, oix, p. 218; oxii, p. 220; Cahoan, AnnaloB de Chim. et Phjs., m, Izii,
p. 376.



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316 Friedd cmd Orq/la on the oombtruUions of

L Boiling'point=120^-140^ in vacuo. Sub8iance=0*4SOO grms.
AgBr==0'6S60 grms.

L Oalcolated for SiCbHisBn.

Br=48-70 52-98

Not succeeding in obtaining a pure monobromated silicic
ethyd, we heated the first product analyzed with acetate of
silver with the intention of obtaining an acetate, and finally of
obtaining from the acetate by saponification with caustic
potash an alcohol The fonnxQas of the bodies thus sought
are, SiCeH C,HA and SiCaH HO. Neither of them, how-
ever, were produced, and we obtained no better result by heat-
ing the bromated product to 200® with an alcoholic solution of
acetate of potassium. The treatment with caustic potash of
the product which had been heated with salts of acetic acid
ML&i to extract the slightest trace of acetic acid, showing that
no acetate had been formed and the principal body whicn was

obtained was the oxyd, j s!/^h!v ^^^^^ formation we had

already noticed in the preparation of silicic ethyd. This pro-
duct boilmg at 228°-231'* was analyzed.

L Boiling'point=228''-231^. Substance^ 0-2222 grms. ; COr=
04743 grms. ; H<iO=0'24:17 grms.

We found that the same oxyd was produced, whether the
bromine were removed fix)m the bromated silicic ethyd by
treatment with acetate of sUver, acetate of potassium or caustic
potash. An analysis was made of a product which was ob-
tained by heating the bromated silicic ethvd repeatedly with
soHd caustic potash, and which boUed at 230 — ^235^

IL J3WZ%:pam^=280*^-235^ /SW«tonoe=0-3305 grms. ; H^O
=0-3660.

iSi(OtH»)t
! 8i(0,Ho).



I.


IT.


Oalcolated for


0=58-21
H=12-09


58-75
12-80


58-54
12-19



The last product was not entirely pure but contained a trace
of bromine, and it is very difficult to remove the bromine com-
pletely fix)m the bromated product, even by a prolonged action
of solid caustic potash. Several analyses which were made of
the liquid, which had not been treated so long a time with
caustic potash, showed that it still contained a considerable
quantity of bromine.

It appears fix>m these data that the bromated silicic ethyd,
when treated with substances containing oxygen combined
with metals having a strong affinity for bromine, loses the atom



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Silicon with Alcoholic Radicals, 817

of ethyl in which the bromine was contained and takes up
oxygen in its placa The reaction is probably represented by
the equation :

2Si(C^s),C,H4Br+2KHO=0 j |H^K2KBr+HaO+CaH4.

When a small quantity of iodine is added to the bromine,
bromid of ethyl is formed by their joint action upon silicic
ethyd at 140*".

The bromid of ethyl thus obtained, distilling at about 40*^,
was analyzed.

1 /SM&Jto7ice=0-6755 grma. ; OO,=0-5565 grma. ; ^aO=0-2855

grms.

CaJkralated for OsHefir.

0=22-42 22-01

H= 4-70 4-58

Iodine is almost entirely without action upon silicic ethyd :

2 e<juivalents of iodine were heated with one equivalent of
silicic ethyd at 180° for 12 hours, very little iodhydric acid and
not a trace of iodid of ethyl were formed. It is well known
that all the other ethyds, obtained by a reaction similar to that
which gives rise to silicic ethyd, are easily decomposed by
iodine with the formation of ioaid of ethyL

The Oxyd of Silicic Tbi-ethyd.

The reaction civen above oflfers the most convenient means
for obtaining me oxyd in considerable quantity, while its
solubility in concentrated sulphuric acid, which has already
been used to separate it from the pure silicic ethyd, serves also
to free it from the traces of the bromated product, which
remain after the action of caustic potash has been carried as &r
as possibla On treating the product analyzed above. No. IE,
witn sulphuric acid a simdl quantity of a gas, which did not
contain oromine was given off, and a small quantity of silicic
ethyd oontaininjg a little bromine remained insoluble in the sul-
phuric acid. The presence of silicic ethyd accounts for the
slight excess of carbon and hydrogen of analysis IL The
larger part was dissolved in sulphuric acid and was separated
from its solution by diluting with water. After having been
washed with water and dried, | of it distilled at 228"*— 230'*.

I BoxUng-point =228*'-230*'. SvhsUince=^0l910 grms. ; COi=

0-1495 arms. ; J3;O=0-2160 grms.
n. Same «^J5tonce=0-2860 grms. ; /Si'Oa=0-1845 grms.

The determination of silicic acid was made by heating the
liquid in a sealed tube with strong nitric acid.



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318 Friedel and Orafis on the combinations of

I. n. Criculatedforo||{C^f2

C=6807 .... 68-64

H=1218 .... 12-19

Si=.... 21-98 22-76

The density of vapor of the oxyd of silicic triethyd was
obtained from the following data :

Difference of weights of the btilb=l'2245 grms.



Temperature of the balance^


13°


Temperature of the oil-bathj


285**


Barometer^


760-0««»


Capacity of the bulb,


284-0 C.C


Air remaining,


1-3 cc.


Vapor density, =8-698




Calculated for 0{ II jg»g*>


8-51



Action of Chlobine on Silicic Ethyd.

When dry chlorine gas is passed into silicic ethyd in a vessel
surrounded by cold water, the liquid is at first colored yellow
by the absorption of chlorine; suddenly this coloration dis-
appears and chlorhydric acid is disengaged, and from that
time forward chlorhydric acid is disengaged as fitst as the
chlorine is absorbed, and no further coloration takes place.
Not even a trace of chlorid of ethyl is produced In order to
avoid the formation of products containing too large a propor-
tion of chlorine, the operation is interrupted from time to time
and all of the liquid, which boils at a temperature lower than
160°, is distilled oflP, and the distillate is treated as before with
chlorine. Finally the residues thus obtained are subjected to a
fractional distillation.

Although we operated on a considerable quantity of silicic
ethyd, and made a large number of fractional distillations of
the chlorated product, we were unable to isolate bodies having
constant boiling points and corresponding in composition to the
mono- and bi-chlorated silicic ethyd. Analyses were made of
the products which distilled at diflferent temperatures after a
nuinber of fractional distillationa

L jRn7%.oom<=180°-190°. Svhstance=^0'21i,0 grms.; 00^=

0-4210; ff^O=0'2086 grms.
n. Same siAstance=0'SS70 grms. ; Ag 01=0-2670 grms.

Repeated distillation decomposes partially the chlorated com-
pound, and products having tne same boiling-point contain a
smaller amount of carbon and hydrogen, after they have been
distilled a number of times.



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Silicon witii Alcoholic RadicaU. 819

ITL This analysis was made from a liquid whose boiling-point was
180° — 185°, biU which had been distilled a larger number of
times than the last
Substance=0'25^grms. 00^=0-4750 grms.; JJ, 0=0-2432 g^rTrw.

The following analyses were made of products belonging to
the same series of distillations as the first.

IV. Boiling-point=U0''-200''. Svbstance=0'2686 grms. ; 00^
=04785 grms. ; jB;O=0-2280 grms,

V. Same suistance=^0'S136 grms, ; AgOl=^0'S2S8 grms.

VL Another product boiling at 190°-200°. Substance=0'2S4t5
grms. OO^=0'4A00 grms. ; 5;0=0-2145.

The composition of all these products approaches that of
monochlorated silicic ethyd.

I. IL m. rV. V. VI. Calculated for SiCeHuCL

C=5415 .... 51-00 50-48 .... 5117 58-72

H=10-92 .... 10-68 9-80 .... 10-06 10-64

Cl=.... 19-39 25-51 .... 19-00

Corresponding results were obtained in the analysis of several
other products distilling at about the same temperature.

Two products boiling at a higher temperature had nearly the
composition of the dichlorated silicic ethyd.

L Boaing-point =200^-210°. Substance =0*2245 grms. ; C0,=

0-3875 ^rT/w. ; 5;0=0-1817.
n. Boiling-point=20b''-'2\0''. Substance=0'24S5 grms. ; C 0^=

0-4155 grms. ; H2O=0'2015 grms.



I.


n.


Calculated for Si CHuGh:


C=47ll


46-58


45-07


H= 8-99


9-19


8-45



The decomposition during distillation is so rapid in the
neighborhood of 230°, that it was pushed no further. Accord-
ing to the above analysis the boiling point of monochhlorated
silicic ethyd is about 180**, and the boiling point of dichlorated
silicic ethyd is about 210°.

After liaving thus endeavored in vain to isolate the mono-
chlorated and dichlorated products,- we noticed that after a large
number of fi'actional distillations a considerable portion dis-
tilled at 190^-195°, and we made an analysis of this product

L Boiling point 190°-195°. Substance^O'2740 grms.; 00^=
0'49S0 grms.; HiO=0'2S80 grms.



L


SiCgHitCL


Mean.


SC^HisCiS.


0=49-07


68-72


49-39


46-07


H= 9-65


10-64


9-54


8-46



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820 Friedel and Grafts on the (x^wbinations of

It appears that, in a mixture of equal equivalents, the two chlo-
rated products have a tendency to distu together at a constant
temperature. Bauer* has noticed an analogous fistct in regard
to the bromids of ethylene and propylene

Distillation having been found inenectual to separate the chlo-
rated silicic ethjds, we sought to obtain a separation of these
products, or better still, of their derivatives, by chemical means,
and in this, after a number of experiments, we succeeded.

We noted that the chlorated products are not attacked by an
alcoholic solution of acetate of potassium, except at a high tern-
} perature, and also that the one containing two atoms of chlo-
rine is more easily attacked than the other. In fact, the pro-
duct containing most chlorine is destroyed at a temperature of
180® to 140*^, while the monochlorated product is not acted up-
on at that temperature, and it can be separated fix>m the other
by taking advantage of this property.

The chlorated bodies distifiinff at ISO*" to 200^ were heated
for 8 to 4 hours, at 180® to 140 , in sealed tubes, with an ex-
cess of melted acetate of potassium dissolved in absolute al-
cohol Chlorid of potassium is precipitated, and on opening
the tubes a combustible gas is disengaged. On adding a con-
siderable quantity of water to the contents of the tubes, the
salts are dissolvea, and an oily liquid is separated. This liquid,
after having been washed with water and oried, was treated with
strong suhmuric acid, in which the monochlorated silicic ethyd
is insoluble, while the products of decomposition of the higher
chlorated compounds are soluble. These last seem to consist
principally of the oxyd of silicic triethyd.

The insoluble liquid was drawn off by means of a pipette,
washed with water, dried and distilled. We did not attempt to
free it from the slight quantity of silicic ethyd which it con-
tained, for fear of losing too much of theproduct, but pre-
ferred to use it for the foflowing reaction. The liquid obtained
by the process described above, distilling 180® to 190®, was
sealed in a tube, with an alcoholic solution of acetate of potas-
sium, and heated at a higher temperature than before, namely,
at 180®, for several hours.

Thb Acetio Bthbb and the Alcohol op Silicic Ethtb.

At 180®, the monochlorated product is acted upon by acetate
of potassium, chlorid of potassium i^ formed, and on opening
the tube no disengagement of gas is noticed, as in the case of
the higher chlorated products. Aft^er adding water to the con-
tents of the tube, a liquid separates out, which is mostly soluble
in concentrated sulphuric acid. The treatment with sulphuric

« Bulletin de la Sod^ Chimique, i, p. 203.



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Silicon with Alcoholic Badicals. 821

acid was resorted to in order to purify the principal product
from a small quantity of the undecomposed chlorated product,
and of silicic ethyd, which remain insolubla The somtion in
sulphuric acid was carefully decanted and slowly poured into a
flask containing a considerable quantity of water in order to
avoid an elevation of temperature. An oily liquid separated
on the surface, which, after having been washed and dried with
chlorid of calcium, distilled almost completely at 208° to 214°.
It had a faint ethereal odor, and smelt also of acetic acid. It
burnt with a luminous flame and a smoke of silicic acid.

This liquid proved to be the acetate derived from silicic ethyd
by the reaction which is represented by the following equation :
SiC8H,Cl+KC8H802=SiC8HwC!3H30a+KCL

It may be considered as an acetic ether, in which the residue

SiCeHj, plays the part of monoatomic radical ^ ^^' [ 0.

At first the method of purification with sidphuric acid was not
employed and the range of temperature at which the ether dis-
tilled was larger. The following analyses were made of such
products :



I. Bail{ng-poi7U==200''-'2W—Substance=0'2226 grms. ; COi=

4845 grms.; ^,0=0-2278 grms,
n. jBbt7%-2>(nn^=209°-215°— /Si^65toncc=0-274S grms.; CO^^

0-5900 577^15.; ^,0=0-2755 grms.
UL Boiling'point=2W-225''—Substance=0'294,0 grms.; 002=

0-6385 grms.; HiO^O'SlOO grms.
IV. Boiling'poirit=219''-224:''—Siibstance=0'201Sgrm^.; COz^

0-4335 grm^; ^20=0-2115 grms.

I. n. m. rv. calculated for SiCsHwCjHjOa.

0=59-88 58-66 59-23 58-73 59-40

H=ll-37 11-15 11-71 11-67 1089

After the treatment with sulphuric acid a perfectly pure prod-
uct was obtained.

L Boiling-point =208°-214°—/SW>5toncc= 0*2190 grms.; 00^—

0-4790 grms.; 5iO=0-2210 grms.
n. BoUing-point =209''-210°—Substance=0'264:0 grms.; 00^=

0-5560 grms.; ^,0=02580 grms.



L


n.


Calculated for SiCsHnQtHtOi.


59-65


59-69


69-40


11-21


11-28


10-89



The results of an elementary analysis are not very decisive of
the purity of a compound of tnis nature, and the best means of
obtaining the true composition of the ether of an acid is afforded
by its saponification with caustic potash.

Ax. JouB. Sol— Sbooivd Sbbibb, Vol. XLIX, No. 147.— Mat, 187a
21



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822 Friedd and OraJU on the oombinations of

Our ether proved to be so stable, that its saponificatioii could
not be completely effected by heating it to 180® with an aque-
ous solution of potash, but it can readily be accomplishea by
heating to 120 -ISO® with an alcoholic solution of caustic
potash.

L 0*5954 gnns. of the ether were sealed in a tube with four
grms. of an alcoholic solution of caustic potash and with an
additional quantity of alcohol The saponincation was effected
by heating the tube to ISO®. Four grma of the potash solution
required for neutralization 10*8 cc. of a solution of sulphuric
acid, containing 01118 grma HsSO^ per cubic centimeter. The
contents of the tube, a^r the potash had been partially neu-
tralized by the acetic acid derivea fix)m tiie saponincation of tiie
ether, only required 8*6 cc. of the sulphuric acid solution for
complete neutralization; consequently the quantity of acetic
acid present in the ether corresponded to 2*2 cc. of the sulphuric



Online LibraryRodolfo Amedeo LancianiThe American journal of science and arts → online text (page 37 of 109)