IMPROVEMENTS IN THE MANUFACTURE OF ACETIC ACID, AND IN THE PREPARATION OF MATERIALS TO BE USED IN THE SAID MANUFACTURE
Year: 1868

page_text: LETTERS PATENT to Henry Bollmann Condy, of Battersca, in the
County of Surrey, Manufacturing Chemist, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF ACETIC ACID, AND IN THE
PREPARATION OF MATERIALS TO BE USED IN THE SAID MANUFACTURE."
Sealed the 24th July 1868, and dated the 12th February 1868.
PROVISIONAL SPECIFICATION left by the said Henry Bollmann
Condy at the Office of the Commissioners of Patents, with his
Petition, on the 12th February 1868.
I, HENRY BOLLMANN CONDY, of Bättersen, in the County of Surrey,
Manufacturing Chemist, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF ACETIC ACID, AND
IN THE PREPARATION OF MATERIALS TO BE USED IN THE SAID MANUFACTURE,"
to be as follows:-
This Invention has for its object improvements in the manufacture
of acetic acid and in the preparation of materials to be used in the
said manufacture.

page_text: I take crude acetate of lime as it is met with in commerce, and
having carefully roasted it I dissolve it in as small a quantity of water
as is convenient, and separate insoluble impurities by filtration; I then
add a strong solution of chloride of calcium; I evaporate if necessary,
and crystallize out from the mixed solutions in accto-chloride of
calcium of which the composition is CaCl, CH, CаО+10 aq., which
is a salt having the property of freeing itself readily from impurities in
crystallizing. I add more chloride of calcium than is necessary to
produce the double salt as it crystallizes advantageously from a solution
of chloride of calcium. I usually redissolve and recrystallize the salt,
and so obtain it in a nearly chemically pure state and in this state it
may be sent into the market and sold as a convenient source of acctic
acid, or I may at once treat it according to a further part of my
Invention to make acetic acid therefrom. Or in place of the process
above described, I take a crude solution of acctate of lime obtained by
neutrallizing pyroligneous acid with lime, and I add chloride of calcium
thereto, obtaining a crude double salt which I roast, redissolve, and
obtain in a pure state by crystallization. In order to make acetic acid I
decompose aceto-chloride of calcium by means of strong acid, I take
the aceto-chloride of calcium purified by crystallization, and I decompose
it with hydrochloric, sulphuric, or other acid, having sufficient affinity
for lime to liberate the acetic acid contained in the salt, and I separate
the acetic acid by distillation from the chloride and sulphate or other.
calcium salt.
The plan I most prefer is the following:-I take of aceto-cliloride of
calcium CaCl, CH, CaO,+10 aqua 100 parts, and of hydrochloric
acid S.G. 1.160, 50 parts each by weight, and after carefully dissolving
the former in the latter I distil off the acetic acid and condense it. This
operation I perform in a suitable still, and in the manner usually followed
in the manufacture of acetic acid by the decomposition of acetate of
lime with hydrochloric acid; or I take of aceto-chloride of calcium 112
parts and add it to sulphuric acid, S.G. 1-845 or thereabout, 24 parts,
which I prefer to employ previously diluted with twice its volume of
water. Having well mixed I distil these materials in a still and
condense the acetic acid in the usual manner.
'

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Bollmann Condy in the Great Seal Patent
Office on the 12th August 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BOLLMANN CONDY, of Battersca, in the County of Surrey, Manufacturing
Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twelfth day of February, in the year of
our Lord One thousand eight hundred and sixty-eight, in the thirty-first
year of Her reigu, did, for Herself, Her heirs and successors, give and
grant unto me, the said Henry Bollmann Condy, Her special licence
that I, the said Henry Bollmann Condy, my executors, administrators,
and assigns, or such others as I, the said Henry Bollmann Condy, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE MANUFACTURE OF ACETIC ACID, AND IN THE PREPARATION OF MATERIALS
TO BE USED IN THE SAID MANUFACTURE," upon the condition (amongst
others) that I, the said Henry Bollmann Condy, my exccutors or
administrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
"
NOW KNOW YE, that the said Henry Bollmann Condy, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, that is to say :-
The object of this Invention is more conveniently and economically
han heretofore to produce from crude or impure acetate of lime (such
as is met with in commerce or such as is obtained by the neutrali-
zation of impure acetic acid) a commercially pure salt, and further to
obtain from such salt a commercially pure acetic acid. For this
purpose I add chloride of calcium to a solution of crude or impure

page_text: acetate of lime and crystallize out from the mixed solutions an aceto-
chloride of calcium of which the composition is CaCl, C,H,, CaO+
10 aq., which is a salt having the property of freeing itself readily
from impurities in crystallizing. Also from this pure salt I obtain a
pure acetic acid by adding to it a strong acid and distilling off the
acetic acid from the mixture.
The following is the manner in which I operate:-For the manu-
facture of the aceto-chloride of calcium for the subsequent manufacture
of pure acetic acid, any inferior acid contaminated by empyreumatic
flavours such as that obtained by the distillation of commercial acetate.
of lime. with sulphuric or muriatic acids may be employed, but the
most practical and economical plan and that which I prefer is as
follows: I take of commercial acetate of lime known as distilled,
acetate of lime 8 cwt., and dissolve it. by boiling in 500 gallons of
water, this I filter or allow to settle till the next day when I dissolve.
in it, with heat and agitation, a quantity of dry chloride of calcium
equal in weight to seven-tenths of the acetate of lime employed. If I
use commercial chloride of calcium or a strong solution of chloride. of
calcium, I take into calculation the water present in the same, and
employ an additional quantity of chloride to compensate. This mixed
solution of acetate and chloride of calcium containing in addition to the
quantity necessary to form the aceto-chloride an excess, of about 20%
of chloride, I by good management obtain when boiling hot or nearly
so at a specific gravity of 30 degrees Beaumé, if it should be of a lower
specific gravity I evaporate to this required strength, if it be too
strong I dilute it to the same point, I then draw it off to crystallize.
When cold and a crop of salt (aceto-chloride) has crystallized out, I
draw off the mother liquor and evaporate it down till the. hot liquor
shews a strength of 31 degrees Beaumé, when I draw it off to crystallize
again after which by repeated evaporations and crystallizations. I
obtain three other crops of aceto-chloride.
For the 3rd crop I draw off the liquor boiling or nearly so at 33° Beaumé.
4th.
"
"
"
5th
"
"
"
"
"
"
"
33.
33
35°
33.
36°
33,
These five crops are of tolerably uniform quality and leave. by far

page_text: sulphuric or hydrochloric acid for producing an inferior acetic acid.
For manufacture of the pure salt I take these 5 crops after they have
been well washed and drained, and. I redissolve them in twice their
weight of water, filter the solution (I prefer to filter it through
animal charcoal), add a further quantity of 10 per cent. or thereabout
of chloride of calcium, and evaporate to 29° Beaumé, at which strength
I obtain a good crop of white salt. The mother liquors from this salt
may be evaporated down to obtain a second crop of pure salt, I draw
off this hot liquor to crystallize at 30° Beaumé for the. second crop, 31°
for the third crop, 32° for the, fourth crop, and after obtaining the..
fourth crop turn the mother liquor into the original solution of the
acetate and chloride of calcium after the first. of the 5 crops. of rough
salt referred to has been obtained.. Commercial brown acetate of lime.
or even crude, pyroligneous acid may be employed for this process but.
not with the same advantage. In the case, of brown acetate of lime,
it is only necessary to observe that. the weight of acetate of lime.
employed. should be 20 per cent.. more. than that of "distilled"
for a given weight of chloride of calcium, i.e.,. about 12 parts: brown.
acetate to 7 parts dry chloride, that, the specific gravity of the. liquor
drawn off for obtaining each crop of salt (aceto-chloride) must be
adjusted or regulated by experiment. as, no two samples of brown.
acetate of lime are. quite alike, and that it will depend in each case
on the care with which the acetate may have, been prepared. It. can.
be ascertained during the process: of evaporation by cooling and
crystallizing a sample, after the boiling or hot liquor has attained. 30°.
Beaumé. If after cooling a good crop of salt is not obtained. it,
must be evaporated, further until that object is: accomplished. To
obtain this, salt by the employment of crude, pyroligenous acid. it is.
necessary to neutralize, with lime and to estimate: the. quantity of
dry brown acetate it contains by evaporating a small portion to: dryness:
and weighing the product. If the solution contains one. part. of, brown
acetate in 10 parts it will be simply necessary to bear in mind that twelve
parts of the dry acetate in it require seven parts of chloride: of calcium,
and that for the, first. crop it must be evaporated to 32° Beaumé, then the
tendency to crystallize estimated by a sample taken out hot and allowed
to cool, and the required strength for crystallization attained. As a rule
the mother liquors in all cases. require to be evaporated to half their
bulk to yield a. further crop. of salt, and then the tendency to crystallize
can be ascertained. When working upon commercial acetate of lime;

page_text: I prefer before commencing the process above described to roast the
acetate, so as to destroy some of its impurities. I employ for this
purpose a large iron retort, say, three feet six inches in diameter, and
six feet long; near the bottom I place a grating so arranged as to touch
the sides of the retort at a few points only, so that conduction of heat
from the sides may be but small. The acetate of lime is placed in sheet
iron trays about two inches deep which are placed in the grating one
over the other, until the retort is filled, the trays are separated by iron
rods laid in between them and care is taken to keep them out of contact
with the sides of the retort. The retort is gradually fired until the
outlet or head passing from the retort becomes heated by the escape of
steam, the fire is then steadily kept up but not raised higher until
this escape pipe commences again to cool down which indicates that
the greater part of the water and impurity have been driven off. The
fire is now let out, and when cool or nearly so the charge is drawn,
the operation generally takes about 48 hours for its completion. When
a solution of acetate of lime obtained by neutralizing impure acctic
acid is operated upon, the aceto-chloride may be similarly roasted before
redissolving and recrystallizing it. Roasting the accto-chloride may
also be done when working on commercial acetate of lime in place of
roasting the acetate. Or in lieu of roasting I filter the original
solution of acetate and chloride, or the acetate of lime alone through
animal charcoal, which I find has a remarkable affinity for or power
of separating the empyreumatic impurities from the accto-chloride and
though in a much less degree from acetate of lime. In order to make
acetic acid I decompose the aceto-chloride of calcium by means of
strong acid, I take the aceto-chloride of calcium purified by crystalliza-
tion, and I decompose it with hydrochloric, sulphuric, or other acid
having sufficient affinity for lime to liberate the acetic acid contained
in the salt, and I separate the acetic acid by distillation from the
chloride, and sulphate, or other calcium salt.
. The plan I most prefer is the following:-I take of aceto-chloride
of calcium 112 parts, and add to it sulphuric acid S.G. 1.845, or
thereabout, 24 parts, which I prefer to employ previously diluted with
twice its volume of water; having well mixed I distil these materials
in a still, and condense the acetic acid in the usual manner. To render
this acid quite pure, i.e., free from hydrochloric acid, I distil it again
off alkali or acetate of soda employed in the proportion of 1lb. to

page_text: 10 gallons of acid; or I take of aceto-chloride of calcium 100 parts,
and of hydrochloric acid S. G. 1.160, 50 parts each by weight, and after
carefully dissolving the former in the latter I distill off the acetic acid
and condense it. This operation I perform in a suitable still and in the
manner usually followed in the manufacture of acctic acid by the
decomposition of acetate of lime with hydrochloric acid. This acid I
also redistil with sufficient alkali to retain any slight trace of hydro-
chloric acid which may have passed over with the vapour in the first
operation. I would remark that the preparation of acetic acid from
the aceto-chloride as above described is altogether new and it is an
important part of my Invention. Also that in some cases it may be
convenient to prepare the aceto-chloride from the crude acetic acid or
acetate as above described, and to send this material into the market to
be used by the purchaser as a convenient source of acctic acid, the
purchaser will then treat the aceto-chloride with strong acid according
to the latter part of my Invention. In many cases the preparation of
the aceto-chloride may advantageously be conducted on the spot where
wood is distilled to obtain acetic acid, as for example, in foreign
countries where wood is cheap and the aceto-chloride may then be
imported into this country for the process of producing the pure acetic
acid to be completed.
In witness whereof, I, the said Henry Bollmann Condy, have
hereunto set my hand and seal, this Eleventh day of August,
in the year of our Lord One thousand eight hundred and sixty-
eight.