An Improved Process for Purifying Alcohol and Obtaining Aldehydes and Acetones.
Year: 1888

page_text: Date of Application, 8th May, 1888
Complete Specification Left, 17th Oct., 1888
Complete Specification Accepted, 23rd Nov., 1888
PROVISIONAL SPECIFICATION.
An Improved Process for Purifying Alcohol and Obtaining
Aldehydes and Acetones.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention which has been com-
municated to me from abroad by La Société Francaise des Alcools purs of Paris in
the Republic of France to be as follows:-
―
This Invention relates to an improved process for purifying crude alcohols
consisting essentially in separating the alcohol from the aldehydes, acetones etc.
which generally accompany it by causing these impurities to form stable com-
binations resulting from the action of alkaline bisulphites and sulphites upon the
crude alcohol.
Aldehydes and acetones form with bisulphites crystalline combinations that are
soluble with difficulty in alcohol, less soluble in water and still less in a concentrated
lye or solution of alkaline bisulphite. This property heretofore utilised solely in
the purification of aldehydes or acetones is applied according to this invention to the
treatment of impure alcohols and forms the basis of the general system or process
hereinafter described.
In treating aldehydes or acetones with bisulphite of soda in the usual manner with
a view to their purification a crystalline compound is produced which is collected and
purified the mother liquids or waters being thrown away. In this improved process
for purifying alcohols on the contrary the mother liquids resulting from the treatment
of the impure alcohol with alkaline bisulphites are preserved in order to be treated as
hereinafter described with a view to extracting therefrom the alcohol in a chemically
pure condition: the aldehyde sulphites which constitute the residue of the operation
are also treated as hereinafter specified in order to separate or obtain aldehyde fit for
commercial purposes.
A combined or general system of treatment or process is thus
formed comprising on the one hand obtaining the alcohol in a state of purity and on
the other hand the production of commercial aldehyde.

page_text: Having thus stated the general principles of the invention I will now proceed to
describe the series of operations employed in carrying out the same in practice taking
for example the treatment of crude ethylic alcohol of commerce the treatment of
other alcohols being carried out under analogous conditions.
The crude alcohols to be purified are first placed in an apparatus or still whereby they
are fractionally divided on the one hand into alcohols containing the aldehydes,
acetones etc. and on the other hand into a less volatile part which remains in the boiler
and which contains the surplus alcohol.
The first part of this treatment or fractional distillation is continued until the alcohol
remaining in the apparatus cease to contain either aldehyde or acetone.
The alcohols separated and containing all the aldehyde in the crude alcohol are
placed in vessels where they are acted on by a concentrated lye at about
30 degrees Beaumé of alkaline bisulphite in suitable quantity to form the aldehyde
sulphites and acetone sulphites and leave a small excess of alkaline sulphite in the
liquid.
When the crude alcohol is known to contain butylic aldehyde it is necessary to
add to the bi sulphite some neutral sulphite which forms with this aldehyde a more
stable combination than the bisulphite. This addition should be made in the proportion
necessary to form with the butylic aldehyde the definite combination corresponding to
the ordinary aldehyde sulphites.
Under these conditions the aldehydes and the acetones combine with the bisulphites
or sulphites and crystals of those combinations are or are not produced according
to the proportion of aldehyde contained in the liquids and the degree of solubility
of these combinations.
Whether the crystals are formed or not the entire mass is then placed in a
distilling apparatus where all the alcohol is distilled off. Being contaminated with
sulphurous acid at the first distillation it is distilled a second time in the presence
of a base such as soda potash or lime and the alcohol thus obtained is chemically pure.
At the conclusion of the first distillation there remains in the boiler a liquid con-
taining the aldehyde sulphites and the acetone sulphides which are treated in the
ordinary way in order to obtain the aldehyde and the acetone.
This improved process for purifying crude alcohol thus enables the aldehydes and
acetones to be obtained as a direct result of the said process whereas these products have
heretofore been obtained by a special process consisting in oxidising the corresponding
alcohols.
The less volatile part remaining after the fractional distillation of the crude alcohol
and containing the surplus alcohol is rectified by the usual treatment.
Dated this 8th day of Max 1000
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C.,
Agents.

page_text: An Improved Process for Purifying Alcohol and Obtaining
Aldehydes and Acetones.
I JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention which has been com-
municated to me from abroad by "La Société Française des Alcools purs "of Paris in
the Republic of France and in what manner the same is to be performed to he
particularly described and ascertained in and by the following statement:-
--
This Invention relates to an improved process for purifying crude alcohols and it
consists essentially in separating the alcohol from the aldehydes, acetones etc. which
generally accompany it by causing alkaline bisulphites to act in conjunction or .not
with sulphites upon the crude alcohol as hereinafter described and form stable
combinations with these impurities.
Aldehydes and acetones form with bisulphites crystalline combinations that are
soluble with difficulty in alcohol, less soluble in water and still less in 'a concentrated
lye or solution of alkaline bisulphite. This property heretofore 'utilised solely in the
purification of aldehydes or acetones is applied according to this invention to the treat-
ment of impure alcohols and forms the basis of the improved process hereinafter
described.
In treating aldehydes or acetones with bisulphite of soda in the usual manner with a
view to their purification a crystalline compound is produced which is collected and
purified the mother liquids being thrown away. In treating alcohol according to this
improved process the mother liquids resulting from the treatment of the impure alcohol
with the alkaline bisulphites are preserved and the alcohol is extracted therefrom in a
chemically pure condition. The aldehyde sulphites (or acetone sulphites) which
constitute the residue of the operation are also obtained in the form of commercially
valuable products. A combined or general system of treatment or process is thus
formed comprising on the one hand obtaining the alcohol in a state of purity and on
the other hand the production of aldehyde and acetone.
Having thus stated the general principles of the invention I will now proceed to
describe the series of operations employed in carrying out the same in practice taking
for example the treatment of crude ethylic alcohol of commerce the treatment of other
alcohols being carried out under analogous conditions.
In the first place the crude alcohols to be purified are treated in an apparatus or still
in which the head alcohols or alcohols containing the whole of the aldehydes, acetones
etc. are distilled off and thus separated from the less volatile portion of the liquid which
remains in the heating apparatus and contains the surplus alcohol.
With this object the distillation is continued until it has been ascertained by applying
suitable tests based on known reactions for example that the alcohol remaining in
the apparatus ceases to contain either aldehyde or acetone.
The alcohols distilled off and containing all the aldehyde originally contaminating
the crude alcohol are placed in vessels where they are acted on by a concentrated
lye of alkaline bisulphite at about 30 degrees Beaumé in suitable quantity (to be
ascertained by trials) to form the requisite aldehyde-sulphites and acetone sulphites
and leave a small surplus of alkaline sulphite in the liquid. The proportion of
alkaline bisulphite required to produce this result varies according to circumstances
and may be ascertained by preliminary trials.

page_text: When the crude alcohol is known to contain butylic aldehyde it is necessary to add
to the bisulphite some neutral sulphite which forms with this form of aldehyde a more
stable combination than the bisulphite alone. This addition should be made in the
proportion necessary to form with the butylic aldehyde the definite combination
corresponding to the ordinary aldehyde sulphites.
Under these conditions the aldehydes and the acetones combine with the bisulphites
or sulphites and under suitable conditions form crystals of these combinations and
whether crystals be formed or not the materials are now subjected to distillation
and the whole of the alcohol is distilled off. The alcohol passing off in this distillation
being contaminated with sulphurous acid is distilled a second time in the presence of a
base such as soda potash or lime and the alcohol obtained by this second distillation is
chemically pure.
At the conclusion of the first of these two distillations there remains in the boiler a
liquid containing the aldehyde sulphites and the acetone sulphites which is subjected
to any known or suitable treatment in order to separate the aldehydes and the
acetones.
This improved process for purifying crude alcohol thus enables the aldehydes
and acetones to be obtained as a direct result of the said process these products
having heretofore been obtained by special process consisting in oxidising the
corresponding alcohols.
The less volatile part remaining in the apparatus after the preliminary distillation of
the crude alcohol and containing the surplus alcohol free from the aldehydes and
acetones is distilled or otherwise rectified by the usual treatment.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what I
claim is :-
1. In the purification of distillers and other alcohols the employment of alkaline
bisulphites either alone or mixed with sulphites substantially as hereinbefore described.
2. In purifying alcohol by means of alkaline bisulphites alone or mixed with
sulphites subjecting the crude alcohol to a preliminary distillation whereby a portion
of the alcohol containing the whole of the aldehydes and acetones is distilled off
leaving in the vessel a portion free from these impurities and which may be
subjected to the ordinary processes of distillation or rectification; treating the
alcohol distilled off containing the aldehydes and acetones with a concentrated lye
of an alkaline bisulphite in order to convert the said aldehydes and acetones into
aldehyde sulphites and acetone sulphites (with the employment of a neutral sulphite
when butylic aldehyde is present); distilling the product in order to separate
the alcohol from the aldehyde sulphites and acetone sulphites the alcohol thus
obtained being again distilled in the presence of a base such as soda, potash
or lime in order to free it from the sulphurous acid all substantially as herein-
before described.
3. Purifying alcohols as hereinbefore set forth by means of alkaline bisulphites
alone or mixed with sulphites and extracting aldehydes and acetones substantially
as herein before described without direct and special oxidation of the corresponding
alcohols.
4. The improved process for purifying alcohol and obtaining aldehydes and
acetones substantially as hereinbefore described.
11
L
1000