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A critical study of the Gooch and Havens hydrochloric acid-ether method for the quantitative separation of beryllium and aluminum

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A. Thesis
Presented to
the Faculty of the Department of Chemistry
The University of Southern California
In Partial Fulfillment
of the Requirements for the Degree
Master of Science
Edwin Ralph Calderon
UMI Number: EP41532
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Dissertation ftAfishfeg
UMI EP41532
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J1his thesis, written by
under the direction of h ..l3 F a c u lty Committee,
and a p p ro ve d by a l l its members, has been
presented to and accepted by the Council on
Graduate Study and Research in partial f u l f i l l ­
ment of the requirem ents f o r the degree of
Date .........:....
Faculty Committee
OF BERYLLIUM AND ALUMINUM . . . . . . . . . . . .
Historical Introduction •
A rapid Survey of the Literature
. . . . . .
Scope and Nature of this Investigation
Experimental Work . . . .
. .
. . . .. . . . . . .
. .
Preparation of standard solutions of
beryllium and aluminum chlorides
Test of Gooch and Havens Method . . . . . . . . .
Time and Convenience Studies of Gooch and Havens
Method Compared vith other Methods
. . . . .
The Generation of Hydrogen Chloride Gas . . . . ..
The Keeping Qualities of the Wash Liquid of Ether
and Hydrochloric Acid . . . . . .
. . .....
The Investigation of a Possible Substitute for
Diethyl Ether
. . . ♦ .. . . . . . . . . . .. .
The Investigation of a Less Corrosive and More
Conveniently handled Reagent than Hydrogen
Chloride Gas
The Detailed Application of the Gooch and Havens
Method to Mineral and Ore Analysis * . . . . .
Summary ..........
. . . . . . . . . . . . . . .
.. . .
Historical Introduction
The discovery of beryllium resulted from the Abbe Hatty*s
(1) observation of the close similarity and probable identity
of beryl and the emerald.
At this suggestion Vauquelin (1) made
some very careful chemical analyses of these two minerals, and
found in 1798 that they are indeed identical, and that they
contain a new earth, which he named glucina, but which is now
known, as beryllia.
In speaking of the discovery of beryllium, Fourcroy
once said,
It is to geometry that we owe in some sort of this
discovery; it is that science that furnished the
first idea of it, and we may say that without it the
knowledge of this new earth would not have been acquired
for a long time, since according to the analysis of
the emerald by M. Klaproth and those of beryl by
M. Bindheim one would not have thought it possible to
recommence this work without the strong analogies or
even almost perfect identity that Citizen Hatty found
for the geometrical properties between these,two
s tony foss ils. (1)
As a result of his analysis of a Peruvian emerald,
Klaproth had stated that this gem had the following composition:
Alumina, ^alumine or argilw
Iron oxide
0 .50 $
To explain his extravagance he said, ,3For the specimen
of emerald sacrificed to this analytical process, I am indebted
to the liberal kindness of Prince Dimitri Gallitzin, whose
zeal for the study of mineralogy is most honourably known."(2 )
Beryl had also been analyzed by Bergman, Achard, Bindheim, and Vauquelin, and was supposed to be a calcium and
aluminum silicate.(3 )
The identity of beryl and the emerald
was not suspected, until the famous French mineralogist,
L ’Abb£ Hauy, made a careful study of their crystal forms and
physical properties and was so struck by the similarity of
the two minerals that he asked Vauquelin to analyze them
Although the latter had previously overlooked the new
earth because of its similarity to alumina, he found in 1798
that the hydroxide that precipitates when caustic potash is
added to an acid solution of the beryl does not dissolve in
an excess of the alkali.
It also differs from alumina in
other respects, for it forms no alum, it dissolves in ammonium
carbonate, and its salts have a sweet taste.
Vauquelin*s paper read before the French Academy in
1798,(3),(4) proved that beryl and the emerald have the same
composition, and that they contain silica, alumina, and a
new earth, a sample of which he presented to the academy.
At the suggestion of the editors, 1 of the Annales de
Chimie et de Physique, he called the new earth Glucina, meaning
1 Guyton de Morveau, Monge, Berthollet, Fourcroy,
Seguin, Chaptal and Vauquelin.
The specimen of beryl that Vauquelin analyzed was
presented to him by "Citizen Patrin, whose zeal for the
advancement of the sciences is well known to every one of their
cultivators."(3 )
Vauquelin believed that Bergman’s incorrect conclusions
as to the chemical nature of the beryl had been caused by the
unwillingness of his "active mind to submit to the details of
Thus Bergman, and Bindheim as well, had entrusted
their analyses to young pupils who were incapable of distin­
guishing a new substance when they saw it.
According to Bindheim’s analysis the beryl consisted of
64 per cent silica, 27 per cent alumina, 8 per cent of lime,
and 2 per cent of iron (total 101 per cent) (3 ).
When Vauquelin analyzed a Peruvian emerald (5 ) after his
discovery of chromium and glucina, the results differed greatly
from his previous ones and from those of Klaproth.
Chromium oxide
Moisture or dther
volatile matter
He found:
1 4 .00
13 .00
2 .5 6
2 .0 0
J. F. Gmelin’s analysis of a Siberian beryl soon confirmed
Vauquelin’s conclusions as to the essential constituents of that
gem, for he found no lime, but only silica, alumina, glucina, and
small amount of iron fexide (6 ).
Since yttria, as well as glucina
form sweet salts, Klaproth preferred to call the latter earth
beryllia, and it is still known by that name.
Beryl and the
emerald are now known to be a beryllium aluminum silicate,
Be-^AlgC SiOj )g.
Today, as at the time of.Vauquelin et al, the satisfac­
tory separation of aluminum and beryllium is fraught with
Of the numerous methods proposed to solve this
problem, there are three fairly satisfactory methods in use
A brief resume'’of the literature from the time of the
discovery of beryllium to the present day will be presented.
Vauquelin (3 ) first used ammonium carbonate, but his
first separation depended upon the solubility of beryllium
hydroxide ini potassium hydroxide and its precipitation on
Gmelin (7 ) and Schaffgotsch (8) both used this same
method, but it is far from accurate.
Scheerer (9 ) first pro­
posed the separation of the last traces of iron from the
ammonium carbonate solution by means of ammonium sulfide.
Berthier (10) proposed the use of ammonium sulfide as a reagent
but the method was shown to be valueless by Bottinger (11).
In 1850 Rivot (12) proposed the Ignition of the oxides
in a current of hydrogen, whereby the iron oxide was reduced to
metal and could be dissolved out by dilute nitric acid or its
mass determined by the loss in weight.
Debray (13) developed
a separation depending on the action of zinc on the mixed
sulfates, precipitating the aluminum as a basic sulfate, but
the method was never made quantitative.
Joy (14) made a comparative study of all methods proposed
to his time.
Gibbs (15), in 1864, for the first time suggests
the use of sodium flouride to quantitatively separate aluminum
from beryllium, and Pollock (16) showed that'the flouride separa­
tion is exceedingly sharp.
Cook (17), after reducing the iron in hydrogen, volatizes
it in a current of hydrogen chloride.
Havens and Way (18) accom­
plish the same result without previous reduction of the oxide.
Rossler (1 9 ) succeeded in separating beryllium from small amounts
of aluminum by precipitating with ammonium phosphate in the
presence of citric acid.
Vincent (20) uses dimethylamine to precipitate beryllium
salts and finds that the aluminum compound is soluble in excess
of the reagent.
Iron acts like beryllium.
Renz (21) confirmed
this, and stated the same to be true of methyl, ethyl and
diethylamine, and claimed the results to be quantitatively
Zimmermann (22) in I8 87 returned to the old KOH and
sulfite and thiosulfate method without any special addition.
Schier (2 3 ) in 1892, Atkinson and Smith (24) in I8 9 5 ,
and Burgass (2 5 ) in I8 96 separate iron quantitatively from
beryllium by means of nitroso - B - napthol.
Lebeau (26) pre­
cipitates the iron in nitric aifcid solution by potassium ferro-
cyanide, removes the iferrocyanide by cupric nitrate, and
excess copper by HgS.
Hart (27) removes the major part of both
iron and aluminum by careful precipitation of the sulfates with
sodium carbonate, the beryllium being the last to precipitate,
owing to the great solubility of its own hydroxide in its own
Gooch and Havens (28) separate beryllium and aluminum
quantitatively by the insolubility of hydrous aluminum chloride
in a miacture of hydrochloric acid and diethyl ether which has
been saturated with hydrogen chloride gas.
This is the method
here investigated, and is the subject of this paper.
Haber and Van Oordt (29) dissolve basic beryllium acetate
in chloroform, leaving behind aluminum and iron as acetates,
layers(3 0 ) removes iron electrolytically from a slightly acid
solution of the sulfates using a mercury electrode.
Parsons and Robinson (31) separate basic beryllium
acetate in a pure state from other acetates by means of its
ready solubility in hot glacial acetic acid and comparative in­
solubility in the same reagent when cold.
Parsons and Barnes
(3 2 ) separate beryllium and aluminum quantitatively by taking
advantage of the insolubility of aluminum hydroxide and ferric
hydroxide in a boiling ten per cent sodium bicarbonate solution,
and of solubility of beryllium hydroxide in the same medium.
Glassman (33) separates aluminum and beryllium quanti­
tatively by treating a slightly acid mixture of their salts
with an excess of sodium thiosulfate solution and heating the
mixture to tolling.
as hydroxide.
The aluminum is completely precipitated
Wunder and Chiladze (34) have developed a separa­
tion "by treating the tared dry chlorides with a saturated
solution of either potassium of sodium hydroxide, until dis­
400 ml of water are added and the whole toiled for
one hour, the volume teing kept constant.
Beryllium hydroxide
is filtered off and determined in the usual way.
The acidi­
fied filtrate yields aluminum hydroxide with ammonia.
To detect and separate aluminum from teryllium, Browning
and Kuzirian (3 5 ) use amyl alcohol on a mixture of the nitrates,
aluminum nitrate teing completely insolutle in amyl alcohol.
It is not satisfactory for a quantitative method.
To separate teryllla from the argillaceous earths,
Wunder and Wenger (3 6 ) fuse the mixture with sodium cartonate,
leach out with water, aluminum and chromium oxides dissolving.
Iron and beryllium oxides remain insolutle.
To separate alumina
and beryllia, the authors fuse with dodium cartonate, dissolve
in water, filter and weigh the ignited residue as BeO, deter­
mining alumina in the filtrate.
Bleyer and Moorman (37) have developed a volumetric
determination of teryllium.
Normal beryllium salts hydrolyze
yielding acid which, acting o m a mixture of potassium iodide
and iodate, produces free iodine.
The iodine is distilled in
a current of hydrogen into potassium iodide solution and
titrated with standard thiosulfate.
The results are claimed
to he accurate.
Wunder and Wenger (3 8 ) state that beryllium is precipi­
tated quantitatively by sodium carbonate, while aluminum re­
mains in solution.
Kling and Gelin (39) devised a scheme where­
by basic beryllium acetate is sublimed in vacuo at I65 degrees,
while the acetates or basic acetates of iron and aluminum are
non-volatile under these conditions.
The results are fairly
Copaux (40) sinters one part of beryl mixed with four
times its weight of sodium fluosilicate in a clay or graphite
The fritted mass is pulverized and extracted with
hot water, the sodium fluoberyllate dissolving, leaving insoluble
sodium fluoaluminate.
The reaction is Be^Al2 (SiO-j)g + 6 Na2SiFg=
3 Na2BeF^ + iWa^AlFg + 3 SIF^ + 9 SiOg.
Britton (41) investigated the isoelectric points of
aluminum and beryllium hydroxides and has developed a rather
clean separation.
For the determination and detection of minute
amounts of beryllium Fisher (42) adds an alkaline solution of
quinalizarin (1, 2, 5, 8 - tetrahydroxyanthraquinone) to an
alkaline beryllium .solution giving a distinct blue precipitate
which is satisfactory for the detection of beryllium in the
presence of iron, aluminum, phosphate, tartrate and magnesium.
The precipitate is filtered off and determined colorimetrically.
Moser and Neissner (43) base their separation upon the
different behavior of beryllium from aluminum when tannin is
added to a dilute solution containing ammonium acetate.
Aluminum is precipitated quantitatively, but beryllium remains
in solution.
For the colorimetric determination and detection of
beryllium, Kolthoff (44) uses curcumin.
reagent will show 0,05 Mg Be/liter,
It is stated that the
Kolthoff and Sandell (45)
treat a solution of beryllium and aluminum salts with 8-hydroxyquinoline in dilute acetic acid solution at about 60 degrees.
Dilute ammonium acetate is added until a permanent precipitate
is obtained.
The precipitate of aluminum oxyquinolate Al(C^Hg
0N)^ is filtered, and beryllipa is determined in the filtrate.
This is said to be one of the best methods yet devised,
J^lek and Kota (46) use guanidine carbonate in presence
of tartrate at proper PH to precipitate beryllium.
cipitate is filtered, ignited and weighed as BeO.
not precipitated,
The pre­
Aluminum is
Gaspar y Arnal (47) ■uses calcium ferrocyanide
to precipitate aluminum in presence of beryllium,
Pache (48) developed a method to separate small amounts
of beryllium from large amounts of aluminum.
The alloy is heated
with dilute sodium hydroxide to dissolve most of the aluminum
and zinc.
The beryllium and other hydroxides are dissolved in
nitric acid, 40 per cent sodium hydroxide is added.
The mixture
is neutralized with ammonium hydroxide to precipitate aluminum
ShdsberylHum hydroxides.
This precipitate is dissolved
molar potassium hydroxide, diluted and heated to
40 degrees.
Beryllium hydroxide precipitates and is finally
weighed as BeO.
Nichols and Schempf (49) use tannin to separate aluminum
and beryllium.
They claim that aluminum is completely preci­
pitated by tannin at Pjj 4.6 in presence of beryllium!
beryllium is determined in the filtrate.
The precipitates
yield the oxides, AlgO^ and BeO on ignition.
It is said to be
accurate within 0.4 mg.
This covers the previous work up to the present time.
From survey of the literature it would seem that many satisfac­
tory methods for the determination of beryllium in the presence
of aluminum exist.
The practical fact, however, is that there
is scarcely an element in the whole mineral kingdom which is
more frequently wrongly reported in analyses than beryllium.
Of all the methods proposed there are actually very few that
will lead to accurate results, and, unfortunately, these seem
to require much study and experience before they can be used
effectively by an unpractised analyst.
Among the very few
methods that could be designated as "hopeful11, that of Gooch
and Havens occupies a prominent place.
seems to be seldom used.
And yet this method
This may be largely due to the dis­
inclination of analytical chemists to work with ether and
hydrogen chloride gas.
of close study.
None the less, the method seems worthy
The following Is a brief outline of the research.
The accuracy of separation by the method as origi­
nally given by Gooch and Havens.
Time and convenience studies versus the 8 -hydroxy-
quinoline and sodium bicarbonate methods.
Comparison of the Gooch and Havens method "with
the Parsons and Barnes method for accuracy.
The best technique for carrying out the generation
of, and saturation by, hydrogen chloride gas to avoid dis­
comfort in the laboratory.
The keeping qualities of the wash liquid of ether
and hydrochloric acid.
The investigation of a possible substitute for
diethyl ether, which would be less volatile, less expensive
and less lethal.
The investigation of a less corrosive and more con­
veniently handled reagent than hydrogen chloride gasV
The detailed application of the Gooch Hand Havens
method to mineral and ore analysis,
Preparation of standard solutions of beryllium and
aluminum chlorides.
Forty-one grams of aluminum chloride were
dissolved in water acidified with enough hydrochloric acid to
prevent hydrolysis and made up to a volume of two liters.
This solution was standardized by precipitation of the aluminum
hydroxide from 2 5 .0 ml portions by the addition of ammonium
hydroxide in slight excess’, which is conveniently indicated
by a slight ammoniacal odor.
The precipitate was filtered,
washed and ignited to constant weight-of AlgO^.
The following
results were found:
No. 1
No. 2
Eleven grams of beryllium hydroxide were dissolved in
cold dilute (1:1) hydrochloric acid and diluted to one liter.
2 5 .O ml aliquots were withdrawn, about 100 ml of water added
and brought almost to boiling.
Six normal ammonium hydroxide
is then added dropwise with constant stirring using bromethyl
blue as indicator.
The precipitated beryllium hydroxide was
filtered, washed with a hot solution of two per cent ammonium
nitrate, ignited and weighed as BeO.
It is a good plan, after
filtering the beryllium hydroxide, to redissolve the minute
quantity of the precipitated hydroxide sticking to the beaker
in dilute (1 :1 ) nitric acid, and to reprecipitate with a few
drops of ammonia, adding this to the main precipitate in the
The following results were found:
BeO/ 2 5 ml
No. 1
No, 2
A typical experiment will now be discussed in detail.
Into a 250 ml Erlenmeyer flask were pipetted two 10 ml aliquots
each of the standard aluminum and beryllium chloride solutions.
Then in a small beaker were mixed 10 ml of twelve molar hydro­
chloric acid and 10 ml of ether.
The ether is readily soluble
in the concentrated hydrochloric acid, forming a single phase.
The first product of the reaction between an ether and a strong
acid is an oxonium compound.
The freezing point curve of ether
and anhydrous hydrogen chloride indicates the existence of two
addition compounds, (CgH^JgO'HCl and (CgH,_)20*2 HC1.
In these
compounds the hydrogen atoms of the hydrochloric acid are
attached to the unshared electron pairs of the oxygen atom:
CoHl- : 0 : H+, Cl"
2 5
C0Hc : 8 : H++, 2 Cl“
2 3
The ready solubility of ethers in concentrated acids is
due to the formation of these oxonium compounds.
They are
readily decomposed by water, the ether being thrown out of
solution on dilution.
This mixture of ether and hydrochloric acid is then
added to the standard solutions in the flask.
Two phases will
be found here but on saturating with hydrogen chloride gas, a
homogeneous phase will be found.
The flask is provided with a
good 2-hole rubber stopper (preferrably a new one) carrying
an Inlet tube reaching almost to the bottom of the flask.
is advantageous but not essential to have the end of the tube
drawn out to a fine point.
The stopper is also provided with
a short exit tube.
The flask is then placed under the water tap and a rapid
stream of pure dry hydrogen chloride gas passed in until the
crystalline precipitate of hydrous aluminum chloride is ob­
The gas stream is stopped and 20 ml of ether are added
and again saturated with the gas.
As much heat is evolved on dissolving gaseous hydrogen
chloride, it is essential that the entire flask be kept cold
in order to avoid loss by volatilization of the ether.
is best accomplished by rotating and shaking the flask under
the rapid stream of water, exposing all parts of the flask.
Using a rapid current of hydrogen chloride gas, the
mixture may be completely saturated in thirty minutes.
tion may be considered complete when no more heat is evolved
when the stream of gas is passed through the flask and the
flask held in the hand.
During the saturation, a Gooch crucible is prepared in
the ordinary manner.
It is then washed with strong hydrochloric
acid followed by washing with the wash liquid which consists
of concentrated hydrochloric acid and ether in equal parts
saturated with hydrogen chloride g&a'.
is now ready for use.
The filtering crucible
The beaker and filter are then washed with a hot 2
per cent ammonium nitrate solution.
Usually there Is a minute
quantity of beryllium hydroxide sticking to the sides of even
the cleanest beaker.
This may be swabbed out with a small
fragment of filter paper and added to the precipitate in the
The paper and contents are transferred to a tared
crucible, preferrably of platinum, ignited to constant weight
and weighed as beryllium oxide.
Some authors recommend that the
crucible be covered during the final stage of the ignition.
one desires to do this, the cover should be inverted, as it has
been found that conduction of combustion gases into the cruci­
ble under the wide flanges of a regularly placed porcelain
cover leads to an increase of weight, probably due to formation
of beryllium sulfate.
The writer prefers platinum crucibles,
as the paper burns away much more rapidly.
It has been claimed
by some that beryllium oxide attacks platinum very slightly,
but in this investigation no evidence of this has been found.
Platinum crucibles used almost daily for the. past nine months
have suffered only a few milligrams loss in weight.
Now to return to the aluminum.
The crystalline preci­
pitate of hydrous aluminum chloride AlClj * 6 H20 contained in
the Gooch crucible is dissolved by applying gentle suction and
pouring 50 - 60 ml of water containing a few drops of hydro­
chloric acid through the crucible.
The filtrate is rinsed
into a 400 ml beaker, about 150 ml water added and brought to
a gentle boil.
Six normal ammonium hydroxide is added drop-wise
with constant stirring in slight excess which may be conveniently
determined by carefully smelling the vapors arising from the
heated solution.
After allowing to stand about five minutes, the mixture
is filtered through a nine centimeter number 40 Whatman filter.
It is then washed with a hot 2 per cent ammonium nitrate solu­
tion, ignited to constant weight and weighed as aluminum oxide,
Gooch and Havens (28) determine the aluminum by a novel
and unique method.
After filtration and washing with the wash
liquid, it is dried for one half hour at 150 degrees. . It is
then covered with a layer (about one gram) of mercuric oxide
and first gently heated and then strongly ignited (Hood ).
The reaction is 2 AlCl^ + 3 HgO = AlgO^ + 3 HgClg, but this
method was not used in the present investigation.
The following results were obtained in trying the
method of Gooch and Havens.
AlgO-^ taken
0 .1 2 9 0
0 .1 2 9 0
AlgO-^ found error
BeO taken
BeO found Error
0 .1 9 9 5
0 .0 6 6 0
0 .0 6 5 7
+0 .0 0 0 5
0 .0 8 6 9
This table shows that the method of Gooch and Havens is
reasonably accurate for the separation of aluminum and beryllium;
A distinct tendency toward the contamination of the aluminum by
beryllium or toward incomplete precipitation of aluminum could
not foe detected.
The total time required for a separation such as just
described may be apportioned approximately as follows.
time necessary for the complete saturation of the mixture by
hydrogen chloride gas is about thirty minutes.
For filtration
and washing ten minutes should be ample, as this operation
should be conducted quickly in order that too much hydrogen
chloride gas shall not escape.
Evaporation of the filtrate
to determine the beryllium takes the most time, as it must be
done slowly so that no loss takes place due to spattering.
This takes from thirty to forty-five minutes.
Precipitation, filtration and washing require about a
iialf hour, while ignition and weighing will take from one and
one-half to two hours.
The aluminum may be determined during
the evaporation of the beryllium filtrate.
The total time,
approximately, for the Gooch and Havens separation is three
and one-half to four hours.
The 8-hydroxyquinoline method (45),(50) is very fine for
the separation of these two elements.
The aluminum is precipi­
tated quantitatively as the oxyquinolate Al(C^HgON)^ and may
be weighed as such or may be ignited to the oxide Al20j.
determination of aluminum does not offer any difficulties and
Is rapid, accurate and easily performed.
The accurate recovery
of beryllium in the filtrate, however, presents some difficul­
Apparently the beryllium In the filtrate forms a complex
of some sort with the excess oxine and incomplete precipitation
amounting at times to 20 per cent of the total beryllium oxide
will result.
The filtrate is treated with a slight excess of dilute
ammonium hydroxide to precipitate the beryllium hydroxide in
the usual way.
This is filtered off and reserved for future
The filtrate from this precipitate is evaporated nearly
to dryness or to a very small volume and treated with very
powerful oxidizing agents such as filming nitric and perchloric
This is to destroy the organic matter from the excess
of oxine.
This is tedious and time-consuming.
Some workers have reported privately to Doctor Brinton
that sometimes the oxine will work perfectly and it is not
always necessary to make two berylliuirt precipitations and sub­
sequent destruction of the organic matter.
This erratic b e ­
havior has not yet been satisfactorily explained.
The complete time of separation, and determination, is
quite long - much more time-consuming than the Gooch and Havens
In addition to its being so laborious and time-
consuming, this method is very expensive, as the oxine is diffi­
cult to prepare, and extremely difficult to prepare in an
analytically pure state.
This compound has not yet been
produced in quantity and its expense is prohibitive for many
However, with all its attendant difficulties,
this method in experienced hands is comparable in accuracy to
the Gooch and Havens, ether method.
There is one other method that is in general use for
the separation of these two vital elements.
This is the
sodium bicarbonate method of Parsons and Barnes (32).
method is based on the insolubility of aluminum and ferric
hydroxides in a boiling 10 per cent sodium bicarbonate solu­
tion and on the solubility of beryllium hydroxide in the same
In the present investigation a series of experiments
comparing this method with the Gooch and Havens method and the
oxine method for time and accuracy has been carried out.
Following is a detailed description of this method.
Equal portions of the standard aluminum and beryllium
solutions were pipetted into a 250 ml beaker.
The solution
was made up to about 100 ml,neutralized as nearly as possible
with 6 normal ammonium hydroxide to a slight permanent pre­
cipitate, and 10 grams of solid sodium bicarbonate were added.
The solution must be cold or spattering will occur. .The
beaker was kept covered with a watchglass and the solution
was brought to boiling as quickly as possible and allowed to
boil not more than one minute.
COg is not evolved very rapidly
until the boiling temperature is reached, if the solution is
neutral, but evolution of gas must not be mistaken for boiling.
The beaker is now placed in cold water, and when cool,
the precipitate is filtered and washed two or three times with
hot water.
The precipitate is dissolved on the filter with the
least possible amount of 6 -normal hydrochloric acid, and the
solution is allowed to run into the original beaker.
solution is made up to 100 ml, made neutral by careful addition
of dilute ammonium hydroxide, precipitated again with sodium
bicarbonate as before, cooled, filtered and washed with hot
water, running both filtrates together.
A cloudiness will be observed in the combined filtrates
after washing, which looks as if aluminum hydroxide is coming
through but this need cause no concern as the cloudiness is
due to the addition of water to the strong sodium bicarbonate
The aluminum hydroxide is again dissolved in
6 -normal hydrochloric acid, precipitated with ammonia and
determined in the ordinary way, as it is impossible to wash
out all of the sodium bicarbonate from the gelatinous aluminum
The filtrate from the double precipitation containing
the beryllium in solution, is now carefully acidified with
concentrated hydrochloric acid in a covered beaker.
before neutralization a portion of the beryllium will be
observed being thrown down as the hydroxide, but this will
immediately dissolve on adding more acid.
The solution is
then boiled to remove CO2 in order that no ammonium carbonate
be formed on addition of ammonium hydroxide in slight excess
to precipitate beryllium hydroxide.
The precipitate is
filtered on a 9 cm, number 4-0 Whatman, or other filter paper
of like quality.
The filter and contents are then washed with
about 25 ml hot 2 per cent ammonium nitrate solution.
The precipitate is transferred to a tared crucible and
ignited to constant weight and finally weighed as the oxide BeO,
.1 2 9 0
+ .0 0 3 1
.0 6 6 0
From this table it is seen that the results are too
high for aluminum and too low for beryllium.
The same results are brought out in the following table,
which are the results of Parsons and Barnes.(32)
.0 9 0 7
.0 9 4 5
+ .0 0 3 8
.0 5 7 3
.0 5 6 3
- .0 0 1 0
.1 2 5 2
The advantage of this method is facility of operation,
and it does not require expensive or corrosive chemicals.
is economical in time consumption - the separation just de­
scribed may be done in about two hours.
As previously stated, the chief reason for the relative
unpopularity of the Gooch and Havens method is the use of
hydrogen chloride gas.
The method used in this investigation for the genera­
tion of hydrogen chloride consists of dropping concentrated,
technical hydrochloric acid on concentrated, technical sulfuric
acid contained in a large flask.
The flask is provided with
a -well fitting 2 -hole rubber stopper carrying a dropping
funnel and a delivery tube bent at right angles.
The gas is
passed through a wash bottle containing concentrated sulfuric
As hydrogen chloride attacks rubber, it is well to
have the connections as short as possible.
The gas is then
conducted by means of glass or rubber tubing to the saturation
This consists of an Erlenmeyer flask of the appropriate
size fitted with a 2 -hole rubber stopper carrying an inlet tube
which extends to the bottom and an outlet tube.
To the latter is attached a long rubber tube, which can
be extended into the fume hood, or be inserted into the drain
pipe of the laboratory sink.
By this simple, yet effective,
technique, this gas may be comfortably handled.
This is prepared by mixing equal volumes of chemically
pure diethyl ether and chemically pure 1 2 -normal hydrochloric
The mixture is placed in the absorption flask, put under
the tap, and a rapid current of hydrogen chloride passed in
for at least 30 minutes.
It is then placed in a tight-fitting
glass stoppered bottle and kept in a cool place away from
direct sunlight.
On exposure to direct solar radiation, the
liquid slowly turns to a light yellow color.
It has been
found that it will keep indefinitely if stored in a dark
bottle kept in a cool place.
The purpose of this investigation was to find a sub­
stitute which would be less volatile, less expensive and less
The first solvent tried was methyl alcohol.
10 ml
each of the standard solutions of beryllium and aluminum were
pipetted into a small Erlenmeyer flask.
To this was added
10 ml of 1 2 -normal hydrochloric acid and an equal volume of
absolute methyl alcohol.
The procedure for this experiment
and the following ones were carried out in exactly the same
way as were the experiments verifying the method of Gooch and
The following results were obtained:
AI 2 O5
+O .0 3 0 8
It is obvious that methyl ale ohol could not be used.
Carbon tetrachloride was next tried, and the following results
were obtained:
AI2 O3
Commercial CC1|,
C. P. CClk
An attempt to substitute benzene for ether did not
lead to encouraging results, as the following data, show.
- — „— ...
.... A.— -y*---- »— ..
.0 8 3 9
.0 8 3 0
-.0 0 6 8
+. 0006
* .0 0 3 4
- .0 0 0 9
- .0 0 6 5
.0 5 1 7
.0 5 0 1
+• 0011
- .0 0 0 5
+ .0 0 6 1
These erratic results are probably due to the two
immiscible phases.
Iso-propyl ether Fas then tried.
grade and had many impurities.
This Fas the technical
It Fas purified by distillation
through a Vigreux column; only the fraction boiling at 6 7 -6 9
degrees was collected.
The results with this solvent are given
+ .0 0 1 6
.0 2 3 0
+ .0 0 1 0
a1 2°3
Technical .0864
.0 8 6 0
- .0 0 1 1
- .0 0 1 0
.0 2 2 0
.0 2 2 0
+ .0 0 0 2
This table shoFs iso-propyl ether to be a reasonably
satisfactory substitute for diethyl ether.
Di-iso-propyl ether, or 2 -isopropoxypropane-1- has a
boiling point of 6 7 -'6 9 degrees, and because of its lower vapor
pressure is less subject to fire and explosion hazards than
diethyl ether, and it is therefore much safer to use.
It does not possess the toxic qualities of diethyl
ether, and its cost is much lower.
Iso-propyl ether does not
form a thick, almost sirupy liquid when mixed with an equal
volume of concentrated hydrochloric acid saturated with
hydrogen chloride, as is the case with diethyl ether.
1 Name approved by the International Uninn of Chemistry.
together with its lower vapor pressure, greatly facilitates
the filtration of the aluminum chloride.
In an attempt to solve this problem, several experiments
were tried and are presented here.
Into a 250 ml glass
stoppered Erlenmeyer flask were pipetted 5 ml each of the
standard solutions of beryllium and aluminum chlorides.
this were added 5 ml of 1 2 -normal hydrochloric acid and an
equal volume of diethyl ether.
The mixture was shaken, being
cooled under the tap.
Pure anhydrous lithium chloride was added in small
portions and shaken under the. tap until the salt was dissolved.
The salt was added until no more was dissolved.
The mixture was then filtered through a Gooch crucible
and washed with a wash liquid consisting of diethyl ether and
concentrated hydrochloric acid in equal parts, saturated with
anhydrous lithium chloride.
The precipitate, which consisted
of hydrous aluminum chloride and excess lithium chloride, was
dissolved by applying gentle suction and passing-water through
the crucible.
After diluting to 500-600 ml the aluminum was
determined in the usual way.
The ethereal filtrate containing the beryllium was
carefully evaporated to remove the ether and most of the acid.
It was then diluted to about 600 ml and the beryllium was
determined in the usual manner
(C2h5 )2°
(C3H7 )20
The incomplete precipitation of aluminum is due to the
inability of the lithium chloride to yield sufficient chloride
An experiment using barium chloride was next performed.
Anhydrous barium chloride was used in precisely the same way
as the lithium chloride.
The crystalline precipitate of
excess barium chloride and aluminum chloride was filtered
through a Gooch crucible and washed with a mixture consisting
of ether and concentrated hydrochloric acid in equal parts
saturated with anhydrous barium chloride.
Gooch crucible was rejected.
The residue in the
The filtrate was carefully
evaporated to a small volume and then transferred to a 2 liter
It was diluted to 1200 ml brought nearly to boiling,
and hot 6 -normal sulfuric acid was added dropwise, with
constant stirring,in slight excess.
The precipitated barium
sulfate was allowed to settle for an hour and then filtered
through a number 1, 24-cm Whatman filter.
The barium sulfate
was washed with hot-water and then discarded.
The filtrate, about 1.5 liters in volume, was treated
for beryllium in the regular way.
In this experiment .0452 gram Al20-^ and .0220 grams BeO
were taken.
The weight of the Be© found was .0652 grams,
which is the sum of the two taken.
Therefore, no separation
took place.
Calcium chloride, which is soluble in ether, was con­
sidered, but the problem of separating 20 or 25 grams of cal­
cium chloride from a few milligrams of beryllium chloride
would be more troublesome than generating hydrogen chloride.
Beryllium is found widely diffused in nature in many
The only commercial ore is beryl, the others being
very rare.
The composition of beryl according to the formula
Be^Al2(SiO-j)g is A^O-j 19 per cent, BeO 14 per cent and Si02
67 per cent.
Alkalies (NagO, CsgO, Li20) are sometimes present
replacing the BeO, from .25 to 5 per cent; also chemically
combined water, including which the formula becomes (R2R)0.
6 BeO. 2 A120^. 12 SiOg.
Beryl Is most commonly found in granitic rocks, either
In druses In the granite or in pegmatite veins.
It has also
"been noted In tin ores together with topaz and In mica schists.
The emeralds found at Muzo, Colombia occur in a bituminous
limestone - a most unique type of occurrence.
It Is common practice in silicate ore analysis to fuse
1 part of ore with 4 to 10 parts of sodium carbonate.
large amount of sodium salt thus introduced into the analysis
together with the long time required for fusion makes this
method undesirable.
The desirability of using smaller amounts of flux
was recognized by Finn and Klekokta (51), who showed that
certain ceramic materials, for example, clay, feldspar, and
high slumina refractories, can be successfully broken up
by sintering at 825-950 degrees C. with a portion of sodium
carbonate approximately equal to the weight of the sample.
Hoffman (52), of the Bureau of Standards, has fully
investigated this fine method of decomposing ores.
fusion (more correctly, sintering) is made In a 75 or pre­
ferably a 100 ml platinum dish instead of a crucible.
The same dish is used for not only the fusion, but for the
disintegration of the melt, the evaporation and the ignition
of the silica.
This not only more than halves the time and
labor, but minimizes the danger of loss due to transferring
from one vessel to another.
Using this method, of decomposition in conjunction with
the Gooch and Havens separation, the writer presents a detailed
system of analysis of beryl ore.
The ore should be ground to a fineness of the order of
100 mesh.
,5 0 0 0 gram of the ore is weighed out and placed in
the platinum dish.
.5 0 gram of anhydrous sodium carbonate
is added and the two mixed very intimately by means of an
agate pestle.
The mixture is then brushed into the center of
the dish and the charge flattened out by means of the agate
pestle so that it covers a space about 5 cms in diameter.
The mixture is then covered as evenly as possible witfjr: an
additional half gram of sodium carbonate.
It is now ready to be heated.
Instead of the costly
electric furnaces of the Bureau of Standards, this writer
has found the following method to be perfectly satisfactory.
The dish is covered with a large number 14 poreelain crucible
cover and placed on a large silica triangle supported, on an
iron ring.
The height is adjusted so that the bottom of the
dish is about 6 or 7 cms above the top of a Fisher blast
It is advisable to also use an ordinary Fisher burner
at the same time.
The dish-is heated for 15 to 20 minutes
at a bright red heat and allowed to cool with the cover left
on to prevent loss by flying fragments that might be ejected
on cooling.
20 ml of 6 -normal hydrochloric acid are added to the
cooled melt, the dish is covered, and allowed to digest on
the steam hath until disintegration is complete.
The action
of the acid may he hastened hy occasionally crushing the
layer of, insoluble, silica that tends to cover the unattacked ■
portion of the fused mass.
It is evaporated to dryness on
the steam hath, and kept there*for at least a half-hour to
render the silica insoluble.
The dish is then removed from
the steam hath and allowed to cool.
Then 5 ml of concentrated
hydrochloric acid are added and the dish is again placed upon
the steam hath for about 5 or 10 minutes, hut not longer, as
silica is appreciably soluble in hot concentrated hydrochloric
The object of warming is to dissolve all basic salts.
Then 15 ml of hot water are added and the dish is gently heated
over a small flame while stirring.
The solution is filtered through a 9 c m , number ifO
"Whatman filter, collecting the filtrate in a 600 ml beaker.
All the silica is carefully washed onto the filter by hot
dilute hydrochloric acid (2:98).
About 200 ml is used.
The next step is the ignition of the silica.
though we are not interested in determining the silica, it is
necessary to ignite it, treat with hydrofluoric acid, and fuse
the residue with pyrosulfate to recover the very appreciable
amount of beryllium present in the silica.
This cannot be
washed out and mu3t be recovered by the process to be described
The filter and contents are transferred to a platinum
crucible, and the paper is burned off, leaving the white silica
The silica, when cool, is moistened with 2 - 3 ml water and
drops of 18-normal sulfuric acid are added.
Then about
10 ml of 4-8 per cent hydrofluoric acid are added and the
crucible placed on the steam bath until most of the liquid
has evaporated.
The remaining liquid is carefully volatilized
by heating over a small free flame until 50-^ fumes cease to
be evolved.
It is then heated to a red heat for a few minutes.
There is quite an appreciable residue.
This is dissolved by
adding about 5 grams of potassium pyrosulfate and gently fusing
for about 10 - 15 minutes, or until a clear melt is obtained.
The melt is allowed to cool, the crucible is half filled
with water containing a few drops of hydrochloric acid and
gently boiled.
This is repeated 2 or 3 times until all is
The solution is passed through a filter (a number 1
Whatman is satisfactory) into the main solution.
This now
contains all the beryllium, aluminum and iron.
This solution is now heated almost to boiling and
6 -normal ammonium hydroxide is added dropwise, with constant
stirring, in slight excess.
The precipitate, which consists
of the hydroxides of aluminum, beryllium and iron, is filtered
through an 11 cm, number 1 Whatman fitter, and the filtrate
is rejected.
The filter and contents are then transferred to the
600 ml heaker in which the precipitation took place, and the
precipitate is dissolved in the least possible volume of
12-normal hydrochloric acid.
About 20 ml is required..
solution is then transferred to the Erlenmeyer (absorption)
flask, and an equal volume of pure isopropyl ether is added.
The mixture is saturated with hydrogen chloride as previously
described; 20 ml more of the ether being added after the
appearance of the fine crystalline precipitate of hydrous
aluminum chloride, and again completely saturated.
The mixture
is filtered through a Gooch crucible, and washed with the wash
liquid as previously described.
The aluminum may be determined, if desired, exactly as
described previously.
It is in a pure state; the iron being
in the filtrate with the beryllium.
The filtrate is evaporated
on the steam bath to remove the ether, and then on the hot
plate to remove most of the hydrochloric acid.
The concentrated solution is then diluted to about
250 ml, heated almost to boiling, and 6 -normal sodium hydroxide
is added dropwise with constant stirring until a good excess
has been added.
This is to separate the iron from the beryl­
lium; beryllium being amphoteric, its hydroxide is soluble in
alkalies, while iron does not show this property.
The beaker
is allowed to cool somewhat, and the iron precipitate is then
filtered through an 11 cm, number 1 "Whatman filter.
The filter
and contents are then returned to the beaker in which the
precipitation was made, the precipitate is dissolved in dilute
hydrochloric acid, and a second precipitation is made, the
second filtrate being run into the first*
This is done because
the gelatinous ferric hydroxide occludes some of the soluble
sodium beryllate.
The filtrate, now containing only the beryllium as
Na2 Be02, is carefully acidified by adding concentrated hydro­
chloric acid dropwise with constant stirring.
When neutrality
is reached, a portion of the beryllium will be observed to be
thrown down, but this immediately dissolves on adding a little
more acid.
The solution is now on the acid side and is now ready
for the final precipitation.
The solution is heated almost
to boiling and 6 -normal ammonium hydroxide is added drop by
drop, with constant stirring, until its odor is very distinctly
The mixture is boiled for a moment and allowed
to cool so that the beaker may be grasped with the hand.
is then filtered through a 9 cm, number 40 Whatman filter and
washed with a hot 2 per cent ammonium nitrate solution.
The filter and contents are transferred to a tared
platinum crucible and ignited to constant weight and weighed
as BeO.
This system of analysis is not only easily performed,
but it is capable of obtaining good results.
A sample of ore
-was furnished this worker by Doctor Brinton and was subjected
to the analysis.
The results are given below:
Weight sample bottle before
Weight sample bottle after
Weight of sample
Final weight crucible + BeO
Final weight crucible
Weight BeO
Run I
Run II
= 8.72$ BeO
This compares not too unfavorably with the result of
8.52 per cent BeO, obtained in Doctor Brinton’s laboratory, by
the most refined oxyquinolate method.
It was thought worth while to try decomposing beryl by
passing silicon tetrafuoride over the finely powdered ore at
a temperature estimated to be between 650 and 850 degrees C.
This has been attempted by Claffin (53) on a commercial scale.
This would be of great advantage to the analyst, as only the
beryllium would come into solution.
The reaction is
2 BejjAig (SiO^ )|? + 5 S i % = 6 BeFg + 2 AlgO^ + 15 SiOg.
The silica and aluminum oxide are insoluble in water,
while beryllium flucride is extremely soluble.
are no alkalies introduced from any fluxes.
Also, there
The experiment was performed by weighing a small
quantity of the same ore as used in the former experiment into
the platinum dish and passing in silicon fluoride.
The dish
was provided with a copper cover through which passed a tube
of copper which was connected to the silicon tetrafluoride
The method used in this investigation to prepare
silicon tetrafluoride consisted of a mixture of fluorspar
and white sand in equal proportions heated in a thick flask
with thrice its weight of concentrated sulfuric acid.
action is:
The re­
2 CaP2 + 2 H2S0^ + SiOg = 2 CaSO^ + SiF^ + 2 HgO
After passing the gas over the heated ore for one hour
the dish was removed from the flame.
"When cold 25 ml of water
were added and the solution was vigorously stirred while it
was gently warmed.
The liquid was decanted through a filter;
the residue was washed and then rejected.
The colorless filtrate was evaporated to dryness in
the platinum dish and then evaporated to strong fumes with
5 ml of concentrated sulfuric acid to expel the fluoride.
It is absolutely necessary to eliminate all fluoride
before precipitating beryllium, as it forms a complex, BeF^J
and thus escapes complete precipitation as hydroxide.
After about half of the sulfuric acid was volatilized,
the solution was diluted to about 250 ml.
This dilution is
necessary, as there must be no large amounts of sulfate present
when beryllium is being precipitated, since the hydroxide is
rather soluble in the sulfate.
The beryllium was then pre­
cipitated with ammonia in the usual manner, filtered, ignited
and weighed.
The weight of the BeO, from .5001 grams of ore,
was only .0 2 3 1 grams, or less than 50 per cent extraction.
However, the writer believes that under a slight pressure,
say 2 or 3 atmospheres, this process may be more successful.
In this paper an historical account of the
discovery of beryllium and a brief survey of the literature
concerning the analytical separation of beryllium and aluminum
have been presented.
The accuracy of separation as originally claimed by
the discoverers of the hydrochloric acid-ether method was
The technique for the safe and comfortable manipulation
of hydrogen chloride gas as used in this process was described.
A satisfactory substitute for diethyl ether has been
found; namely, isopropyl ether.
Attempts were made to sub­
stitute metallic chlorides for hydrogen chloride gas, but were
unsuccessful, as a sufficiently high chloride ion concentration
could not be obtained,
A new method by Hofftnan (5 2 ) was cited for decomposition
of silicates using only 2 parts of sodium carbonate to one
part of sample, and has been found perfectly reliable.
This is applied to beryllium ore analysis, in conjunc
tion with the modified Gooch and Havens method.
The Parsons and Barnes sodium bicarbonate method was
compared for accuracy and convenience of time and labor.
A method of decomposing beryl by passing silicon
tetrafluoride over the heated ore is described, but was not
found satisfactory under analytical conditions.
Mellor, "Comprehensive Treatise on Inorganic and
Theoretical Chemistry,".Vol. 4, Longmans, Green and Co.
London, 192 3 , p. 204. .
Klaproth, "Analytical Essays Towards Promoting the
Chemical Knowledge of Mineral Substances," Cadell and Davies
London, 1801, p. 325*
Vauquelin, "Analyse de 1 ‘Aigue marine, ou Beril; et
decouverte d ’une terre nouvelle dans cette pierre/'
Ann. Chim. Phys. 1 , 26, 155 (May(30 Floreal), 1 7 9 8 ).
Jagnaux, "Histoire de la Chimie," ref. (2) Vol. 2, p. I6 9 .
Vauquelin, "Analyse de 1 1Emeraude du Perou " Ann. Chim.
Phys. 1 , .26, 259 (June(j50Prairial), 1798).
Gmelin, Johann Friedrich, "Analyse du beril de Nertschinsk
en Sib^rie, et examen de quelques caracteresqui distinguent
la glucine qu 1il contient," ibid, 1 , 4_,27 (0 ct . ( 3 0
Vendema ir e),18 03
Gmelin, J. F., Ann. Physik, 5 0 ,
Schaffgo.tsch, Ibid.,
50, I8 3 .
Scheerer, Ibid., 5 6 , 479.
Berthier, Ann. Chim.
3 ,
7 ,7 4 .
Bottinger, Ann, fxl, 397.
Rivot, Ann. Chim. Phys.,
Debray, Ibid., 2 ,
Joy, Am. J. Sci.,
Gibbs, Ibid.,
, 3 0 , 183 (1 8 5 0 ).
44, 1.
2 , 36, 83.
2 ,3 7 .,• 346 (1864)
Pollock, Trans. Roy. Dublin Soc.,
Cooke, Am. J. Sci.
2 , 42_,
Havens and Way, Ibid.,
2 , 1904, 139.
, 8 , 217.
Rossler, Z. anal. Chem. 17, 148.
Vincent, Bull. Soc. Chim. 33» 157•
Renz, Ber., 36, 2751.
Zimmermann, Z.
Anorg. Chem., 1 5 , 286 (1 8 8 7 )
(2 3 ) Schier, Chem. Ztg., 16, 420 (1892)
Atkinson and. Smith, J. Am. Chem. Soc., IJ_, 688 (I8 9 5 )
(2 5 ) Burgass, Z. Angew. Chemie, 596 (1 8 9 6 )
Leheau, P., Compt. Rend. 121, 641.
(27) Hart, J. Am. Chem. Soc. 1 7 , 604.
(28) Gooch and Havens, Am. J. Sci.,
4 ,
4_, 111 (1897)
(2 9 ) Haber and Von Oordt, Z. anorg, Chem., 40, 465
(30) Myers, J. Am. Chem. Soc., 26_, 1124.
(3 1 ) Parsons, Charles L., and Robinson, Ibid., 28,
(3 2 )
555 (1906)
Parsons, Charles L. and S. E. Barnes, Ibid., 28, 1589 (1906
(3 3 ) Glassman, B. Ber., 39 ^, 3366 (I9 0 6 )
(34) Wunder, M. and Chil&dze, N. Ann. Chim. Anal. 16_,
( 35 )
205 (1911)
Browning, Philip and Kuzirlan, S.B., Orig. Com. 8 th Intern.
Congr. Appl. Chem., 1_, 87 (1 9 1 2 )
(3 6 ) Wunder, M. and ¥enger, P. A. Zanal. Chem., 51, 470 (1912).
(3 7 )
Bleyer, B. and Moormann, A., ^The Volumetric determination
of beryllium. 11 Ibid., 5 1 , 3 6 0 ,(1 9 1 2 ).
(3 8 )
¥under and ¥enger, Ann. Chim. anal, 1 7 , 3 63 (1 9 1 3 ).
Kling, A., and Gelin, E. Bull. soc. chim., 15_, 205, ( 1914)
Copaux, H. ^Determination du glucine en beril,*'
Comptes rendus, 168, 612 (1 9 1 9 ).
Britton, Hubert Thomas Stanley. ^Electrometric studies
of the precipitation of hydroxides.M
J. Chem; Soc., 127, 2120 (1925).
Fischer, Hellmut, Wiss.
99 (1 9 2 6 ).
Siemens Konzern,
Moser, L. and Niessner, M. Monatah, 48, 113 (1927)
Kolthoff, I. M.
J. Am. Chem. Soc., 50, 393 (1928)
Kolthoff, I. M., and Sandell, Ernest B. Ibid., 5 0 , 1900
(1928 )
jflek, A. and Kota, J. Collection Czechoslov.
Chem. Comm. 3., 336 (1931)
Gaspar y Apnal, Teofilo. Anales sociedad espanola
f-Lsica quimica. .3 2 , 868 (1 9 3 4 )
Pache, Erich, Chem. Ztg., 61, 880 (1937).
Nichols, M. L. and Schempf, John M.
Anal. Ed. ILL, 278 (1939).
Ind. Eng. Chem.,
Knowles, H.B., Journal of Research, U.S. National Bureau
of Standards 15, 87 (1936).
Finn, A. N. and Klekokta, J. F., Ibid., 4, 809 (1930)
E P 180.
Hofftnan, James I., Ibid., 25_, 379, Sept. 1940.
Claffin, Harry C., U.S.Pat. 2, 081, 984.
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