Year: 1898

page_text: We, DR CARL UEBEL and CHEMISCHE FABRIK RHENANIA, (an Incorporated
Company) both of Aachen, Kann, Rhenish Province, Prussia, do hereby declare
the nature of this invention and in what manner the same 18 to be performed to
be particularly described and ascertained in and by the following statement. —
This invention relates to a manufacture of polysulphates to serve as a substitute
for concentrated sulphuric acid; according to the present invention such polysul-
phates are produced by heating acid alhali sulphate when mixed together with
aqueous sulphuric acid.
In the production of the polysulphates in this manner, only water passes off,
while in the preparation of highly concentrated sulphuric acid, considerable quan-
tities of sulphuric acid escape together with the water.
A compound of bisulphate with sulphuric acid of the formula NaH SO H₂SO
was first obtained by Schulz (Inaugural Dissertation Berlin 1868) by a different
process, namely by crystallisation of sodium bisulphate in an excess of sulphuric
acid. but no practical application of this process has been made.
Other polysulphates, for example, the pentasulphate of the formula Na S³07
3H2SO4, are produced by the heating of bisulphate with sulphuric acid in
molecular proportions.
The polysulphates obtained according to the present invention by heating acid
sulphate with sulphuric acid constitute a useful substitute for the high grade
and fuming sulphuric acids hitherto used; thus, for example, they produce a more
concentrated and purer acid when used for making nitric acid from saltpetre than
1s produced by the use of sulphuric acid When high-grade and fuming sulphunc
acid are employed in organic processes there frequently ensues a more i luss
deeply seated decomposition of the materials and a consequently impure product
and poor yield By application of sulphuric acid in the form of polysulphates
the decomposing action of the acid is avoided and its tendency to react modified,
whereby uniform products are obtained
The polysulphates can be applied for effecting a whole series of chemical opera-
tions and so far as this invention is concerned it is immaterial what are the final
products of such operations, the essence of the invention being that reactions can
be effected by means of polysulphates which heretofore required the use of highly
concentrated sulphuric acid.
In the preparation of nitric acid by means of polysulphates there is produced
a bisulphate which at the end of the operation may in part be withdrawn from
the decomposing vessel as a liquid. The residue can be re-converted into a poly-
sulphate by addition of sulphuric acid and again used for decomposing saltpetre.
In the preparation of acetic acid from acetate of lime it is useful to add such a
proportion of polysulphate that normal sulphate and sulphate of lime are left, since
in this case the further use of the polysulphate is not practicable owing to the

page_text: admixed sulphate of lime. It is advantageous to leach this residue so as to obtain
Glauber's Balt
The following example serves to illustrate the production of polysulphate. In
an iron boiler some 100 parts of bisulphate are dissolved with the aid of heat in
about 105 parts of sulphuric acid of 60 per cent. strength, or the sulphuric acid
may advantageously be introduced into the molten bisulphate. The water of the
sulphuric acid is thus evaporated fully at a temperature of 260° C. & polysul-
phate of the composition NaH(SO), "being formed. By gradually cooling the
mass the compound may be caused to separate in long, lustrous prisms and finally
solidifies to a solid crystalline cake; it melts at about 95° C By the use of a
vacuum the expulsion of the water occurs at a considerably lower temperature
than that named.
Example of the application of polysulphate in inorganic chemistry:
To the polysulphate prepared in the manner above described is gradually added
the quantity of Chili saltpetre which is by calculation sufficient to produce the
compound NaHSO, and the mixture is warmed A nitric acid containing, on
the average, 95 per cent of HNO3 distils over When the nitric acid has been
completely expelled, there remains a fused mass of bisulphate at a temperature of
2500 C. One half of this 18 withdrawn from the vessel and the remainder is recon-
verted into polysulphate by the addition of sulphuric acid of 60 per cent. strength
and the product is used for the decomposition of a fresh batch of Chili saltpetre.
Examples of the application of polysulphate in organic chemistry;-
_
On warming
(1) In a retort provided with a starring device 100 parts of monosodium disul-
phate are mixed with 100 parts of finely pulverised acetate of lime
the mixture it melts to a magma and the acetic acid is completely evolved calcium
sulphate and normal sodium sulphate being formed. For the better intermixture
of the contents of the retort the acetic acid may at first be retained in the retort
by a reflux condenser. The distillate which is only slightly contaminated with
tarry matter may be separated by rectification into glacial acetic acid and acetio
acid of 80 per cent. strength.
(2) About 100 parts of acetate of lime, about 125 parts of monosodium disul-
phate, and about 60 parts of alcohol are heated together in a retort provided with
a stirring device for some time, a reflux condenser being used. The ethyl acetate
thus produced 18 then distilled over and purified by agitation with soda solution,
dried and rectified.
(3.) 100 parts of naphthalene are heated together with about 170 parts of mono-
sodium disulphate in a boiler provided with a stirring device and immersed in a
steam bath for from 10 to 12 hours After addition of hot water, the unaltered
naphthalene is filtered and the filtrate is neutralised by milk of lime From the
calcium salt other salts or free naphthalenedisulphonic acid can be prepared
(4) 100 parts of aniline are mixed with about 400 parts of monosodium disul-
phate and heated at about from 200° to 220° C, the mixture being stirred the
while, until the mass has completely solidified. By leaching the easily soluble
Balt 18 separated
(5) 100 parts of benzene are mixed with about 300 parts of monosodium dieul-
phate and 120 parts of Chili saltpetre The nitration takes place partially in the
cold and 18 completed by warming. By addition of water the product of the
reaction 18 separated and purified by distillation.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, we declare that what we claim
is:.
~
1 The manufacture of polysulphates by heating acid alkali sulphates with
aqueous sulphuric acid, substantially as described.
2 The use of polysulphates in the manufacture of high grade volatile acids,
such as nitric acid and acetic acid, substantially as described.
3 The use of polysulphates in organic processes, such as the preparation of

page_text: ethers, ethereal salts and sulphonic acids, and in processes of nitiation, condensa-
tion, and oxidation, which processes have been carried out hitherto by the use
of concentrated or of fuming sulphuric acid
A
1
1000
ABEL & IMRAY,
Agents for the Applicants