Improvements in Pyroxyline Solvents and Compounds.
Year: 1893

page_text: Date of Application, 8th Apr., 1893-Accepted, 20th May, 1893
COMPLETE SPECIFICATION.
Improvements in Pyroxyline Solvents and Compounds.
I, LEONARD PAGET of 765 Broad Street, Newark, New Jersey, United States
of America, Chemist, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
My invention relates to improved solvents of pyroxyline and the compounds
therewith obtained. Compounds of pyroxyline are solid, liquid, or of an inter-
mediate state. A solid compound is produced by acting upon soluble pyroxyline
with the vapor of camphor. In such a compound the pyroxyline has suffered what
is known as "conversion." By conversion is meant that the pyroxyline has lost all
structural and cellular form, and has become a homogeneous mass. A liquid com-
pound may be produced by immersion of the pyroxyline in an active liquid solvent ;
in such a solution of pyroxyline conversion has first occurred and is implied. That
conversion has first occurred can be shown by the experiment of treating the
pyroxyline with a minimum amount of the active liquid solvent; then evaporation
of the excess of solvent, if any, leaves a converted mass that by no known chemical
Conversion and
treatment can be brought to the stage preceding conversion.
solution have therefore sometimes been used as synonymous terms in relation to
liquid solvents. Conversion and solution can be produced by a simple solvent
substance, such as wood alcohol, when, generally, the solution can be diluted with-
out limit by addition of the same substance. But there are some substances, as for
instance some essential oils that produce conversion of the pyroxyline and throw out
their own excess, that is, no more oil is taken up by the pyroxyline than is necessary
to the act of conversion, that of solution in the same oil being refused. Conversion
and solution can also be produced by a mixture of substances neither of which is
by itself a solvent, as with alcohol and ether; and it may occur, as it does in this
case, that dilution of the solution may be made without limit by one of the
substances and not by the other, the addition of this other producing precipitation
of the converted pyroxyline. Consequently, besides conversion and solution, there
must be studied the phenomena of dilution, when an attenuated solution of
pyroxyline is desired.
When pyroxyline is converted and dissolved in methyl alcohol, the solution can
be diluted to any desired extent with anhydrous ethyl alcohol, but not with
anhydrous amyl alcohol, because the latter produces precipitation of the converted
pyroxyline at an early stage, which-the-former does not. In fact where in the art
a quick-setting gelatinous, plastic compound is required, a precipitant such as amyl
alcohol may be advantageously employed to bring about a solidification and to set
free the solvent more quickly.
Besides these considerations there are others, especially those relating to degree
of volatility, requiring attention when a more or less dilute pyroxyline compound
is desired; and this sketch of the state of the art is given in explanation of the
object of my invention, which is broadly to extend the list of known solvents and
diluents of solvents of pyroxyline. But more specifically the object of my inven-
tion is to procure solvents of pyroxyline and diluents of solvents of pyroxyline
whose characteristics and properties can be more definitely determined beforehand,
or so-to-say, prophetically, than is the case with those hitherto employed in the
I have discovered such a series of solvents and diluents of solvents of pyroxy-
line in what are chemically known as the mixed ethers, (and compounds of the
mixed ethers,) produced by etherification of mixtures of the primary alcohols under
the action of sulphuric acid or its equivalent, by the ordinary process of etherifi-
cation; and I have found that according to the nature and proportion of the
art.

page_text: primary alcohols and of the acid taken, so can the resultant mixed ether have
certain desired properties not to be obtained by the mixtures of the primary
alcohols, but which might be the resultant of the properties of these alcohols taken
individually, could such an individual use have been possible.
I have found that a mixed compound ether produced, by the distillation with
sulphuric acid and a compounding acid not dissociated by contact with sulphuric
acid at the required temperature, from a mixture of primary alcohols not either
themselves alone active solvents of pyroxyline, nor becoming an active solvent by
their admixture, is generally a powerful solvent of pyroxyline; that is, I have
tested this general statement in a considerable number of combinations and have
yet to find an exception, selecting the constituent alcohols and compounding acid
with the knowledge one skilled in the art of manufacturing pyroxyline compounds
would exercise. For instance, etherification of a mixture of ethyl and amyl
alcohols by sulphuric acid in presence of acetic acid produces a mixed compound
ether, or rather an acetic compound of a mixed ether that is strongly and actively
solvent of pyroxyline and is a diluent of its own, and of other, solutions. By
varying the proportions of the constituent primary alcohols, compounds are
obtainable having varying volatilities.
To carry my invention into effect, I put into a glass still, say 25 parts by
weight of ethyl or grain alcohol, and 25 to 20 parts by weight of fusel oil or amyl
alcohol, with 25 parts by weight of sulphuric acid and 12 parts by weight of
acetic acid, arranging for further supplies continuously, as in the ordinary process
of etherification, should the process be designed to be continuous. But I do not
limit myself to these proportions, as it will be obvious to one skilled in the art that
other proportions may give properties equally desirable as those obtained in the
compound produced with the preceding proportions.
Nor do limit myself to the use of acetic acid. As an instance, I may and do
substitute salicylic acid for acetic acid, and thus obtain a salicylic compound of
amyl-ether which has a solvent action on pyroxyline but is colored in certain pro-
portions of the constituent alcohols and is therefrom objectionable where a colorless
solution is required.
It is generally requisite that these ethers be rectified.
I am aware that mixtures of acetate of amyl and acetate of ethyl have solvent
action on pyroxyline and as such are old in the art, but the compounds I obtain by
my process are not such mixtures, nor have the boiling points nor characteristics
of such mixtures.
I have also found that if a mixture of 7 or 8 volumes of amyl alcohol and
I volume of methyl alcohol be employed as a solvent for soluble pyroxyline there
results no perfect solution and but an imperfect conversion, the pyroxyline presenting
itself in an amorphous condition and having very little coherence.
Such a product is wholly unsuitable to any known application of the art.
But if this mixture of amylic and methylic alcohols be submitted to distillation
in the presence of sulphuric acid, or in other words to a process of etherification by
sulphuric acid, the distillate is a very excellent solvent of pyroxyline of low medium
volatility, and is a diluent of its own (and of other) solution without limit.
Other excellent solvents of pyroxyline are obtained by similar treatment of
mixtures that are themselves solvents without such process of etherification, but
the solvency of which is advantageously modified thereby, admitting, as one such
modification, of effective dilution with such an addition of a precipitant alcohol as
would without such treatment throw down the whole of the converted pyroxyline
in an amorphous condition; such mixtures are, for example,-
For 25 parts by weight of strong sulphuric acid:

page_text: The solvency of the distillates from these alcoholic mixtures increases with the
alphabetical order of the attached letters. And the examples have been taken as
providing by etherification excellent solvents, although very poor solvents them--
selves as regards A. and B. C. is a powerful solvent mixture of low volatility; it
becomes by etherification a more powerful solvent mixture of greater volatility.
I have also discovered that by distilling again a mixed ether either acetic, salicylic,
or like compounding acid an entirely new series of solvents and diluents of
solutions of pyroxyline is obtained, some of which I believe are unknown to modern
chemistry.
To carry my invention into effect I produce a mixed ether by distilling, as
described previously, a mixture of two or more primary alcohols in the presence
of sulphuric acid or its equivalent, and I submit this mixed ether so obtained to.
redistillation with glacial acetic acid, or with a mixture of sulphuric and salicylic
acids. The resulting distillate collected at the boiling point of the mixture is a
powerful solvent or useful diluent of a solution of proxyline.
For instance, I submit a mixture of 25 parts of sulphuric acid, by weight,
25 parts of fusel oil, 15 parts of wood alcohol, and 10 parts of grain alcohol, to
distillation; and I next submit the distillate to redistillation with 15 per cent. of its
volume or less of glacial acetic acid. The resulting distillate of the redistillation is
a powerful solvent of pyroxyline of rather high volatility.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed i declare that what I
claim is
1. A process of making a solvent of pyroxyline which consists in mixing together
alcohols which are not solvents of pyroxyline, adding to such mixture sulphuric and
acetic acids, and distilling.
2. A process of making a solvent of pyroxyline which consists in mixing together
alcohols which are not solvents of pyroxyline, adding to such mixtures sulphuric
acid and an acid that will combine with the mixed ether or ethers produced in the
process of distillation, and distilling.
3. A pyroxyline solution composed of pyroxyline and a mixed compound ether
obtained by the etherification of a mixture of alcohols none of which is itself solvent
of pyroxyline.
4. A pyroxyline compound composed of pyroxline dissolved in any common
solvent mixed with a distillate obtained by etherification of alcohols with sulphuric
acid.
5. A pyroxyline compound composed of a solution of pyroxyline in any common
solvent such solution being diluted with a mixed ether obtained by etherification of
a mixture of alcohols by sulphuric acid.
6. A pyroxyline compound composed of a solution of pyroxyline in any common.
solvent such solution being diluted with ethyl-amyl-ether.
7. A pyroxyline solution which consists of pyroxyline dissolved in a mixed ether
produced by the distillation of a mixture of wood alcohol, fusel oil and sulphuric
acid.
8. A pyroxyline solution composed of pyroxyline dissolved in a mixture of mixed

page_text: ethers produced by the distillation of a mixture of wood-alcohol, grain alcohol, fusel
oil, and sulphuric acid.
9. The process of making a solvent of pyroxyline which consists in mixing two
or more primary alcohols with sulphuric acid, distilling the mixture and mixing the
distillate with an acid which will combine with the ether or ethers so formed, and
redistilling the mixture.
10. The process of making a solvent of pyroxyline which consists of mixing
together two or more primary alcohols with sulphuric acid, distilling the mixture,
mixing the distillate with acetic acid and redistilling.
1000
ww
LEONARD PAGET.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.