Improvements in or relating to the Manufacture of "Artificial Camphor," and its Treatment.
Year: 1895

page_text: Date of Application, 1st Oct., 1895
Complete Specification Left, 1st July, 1896-Accepted, 1st Aug., 1896
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Manufacture of "Artificial
Camphor," and its Treatment.
I, JAMES CHARLES RICHARDSON, of 19 Claremont Square, in the County of
London, N., Electro-chemical Engineer, do hereby declare the nature of this
invention to be as follows :-
This invention relates to improvements in the manufacture of “artificial
camphor," so-called, and its treatment.
Laboratory methods for the production of "artificial camphor," I find come
short in manufacturing practice, and, further, the first product requires additional
treatment to extend its area of usefulness.
My methods may be described as follows:-
The oil (turpentines and like hydrocarbons,-up to the present I find a special
brand of American turpentine the best) to be hydrochloridized is placed in a
containing vessel, tank or tanks of inactive material, in which the temperature of
the oil can be regulated and the liquid kept agitated-the former, say, by a water-
jacket, water-coil or water-bath, or cooled air or equivalent; and the latter by a
stirrer or equivalent placed in the vessel or tank, or motion given to the containing
vessel, or equivalent. The same may be produced by passing a gentle stream or
layer of oil, by any suitable means, over the floor or floors or shelves, or
equivalents, placed in closed chambers, or through a 'scrubber' having perforated
shelves or equivalent, exposing large surface of oil to the gas; or the vapours
of the two compounds may be brought together in a suitable combining chamber.
Into these oil-containing vessels, tank or chamber, is led hydrochloric acid
(bydrogen chloride) gas, generated in the usual way from salt and sulphuric acid
or like, or by electrolysis of a chloride solution, giving off hydrogen and chlorine
gas, which gases may be made to combine by well-known means; or the oil may
rest on the electrolyte.
In the Leblanc alkali process this gas may be obtained cheaply, and I so
obtain it when practicable, in any convenient manner, by tapping the gas-collecting
chambers or pipes. I also attach to the hydrochloridizing apparatus a fan, steam
or other form of exhauster or blower, if desired.
This hydrogen chloride gas may be washed and dried by suitable agents before
admission to the turpentine, and the temperature and pressure of it regulated. The
same may be stored in a gasometer, under pressure if desired, and applied to the
oil under pressure. I may employ chlorine gas, or a mixture of chlorine or oxygen
gas or air and hydrochloric acid if desired, or equivalent halogen combinations, as
hydriodic acid.
The process is made continuous where the supply of hydrogen chloride is
continuous, by fishing out the crystals ("artificial camphor") formed at intervals,
and adding fresh or 'live' oil. This may be effected in a variety of ways. A
simple plan is to provide a perforated tank or jar or filter to catch the crystals,
from which the mother-liquor can drain off. These crystals I allow to drain, and
then wash them in a suitable vessel, as a tank or revolving barrel or like, or on a
or less than
filter, at any suitable temperature, and if desired under more
atmospheric pressure, by suitable agents, such as water, steam, an alkali salt
(including ammonia) solution, alcohol, ether, mother-liquor, or 'live' turpentine,
benzene, alcoholic solution of potash or soda, or like (or with an acid); the object

page_text: being to obtain the crystals clean and bright, free from mother-liquor (which is
acid), neutral, and stable.
The mother-liquor may with advantage be added to fresh batches of oil to be
treated; the same I find facilitates production. The crystals may be obtained of
good color and fairly dry by efficient draining off of mother-liquor-but not neutral,
hence the foregoing neutralizing treatment.
I sublime, or distil, these crystals by heat in a novel manner, that is to say, with
water or steam, to which may be added an alkali salt or alkaline earth or like,
by which the temperature of the bath may be increased and acid products
neutralized. The product may be stirred or agitated during sublimation, or by
steam. There may be added to the crystals to be sublimed or placed in the
subliming bath, an oxidizing agent, as an oxide, hydroxide, or equivalent, if
desired.
At this stage of the process I produce a more valuable compound than has
hitherto appeared, of considerably higher melting-point than the original crystals,
and therefore more applicable for many purposes. [I am aware of the difficulties
encountered in the sublimation of this product.]
The sublimate may be treated with ammonia gas or solution, or equivalent, to
neutralize any free acid produced by 'cracking' of the compound under heat. As
a rule, however, by careful heat distribution, I do not find this necessary; but
where necessary I apply it, washing out any excess of ammonia with water.
The original crystals may be dissolved in any suitable solvent, and the solution
or crystals produced therefrom, made the starting-point in the sublimation process,
or the same (or sublimate similarly treated) made the manufactured product for
medicinal purposes. A second direct sublimation in an alkaline bath is satisfactory
for many purposes. The original crystals I sometimes heat in a concentrated
(alkaline) bath with advantage.
Where the sublimate is wet, it may be dried by filter-press, or equivalent, or
other well-known means.
Pressure gets rid of most of the moisture; and as the sublimed product 'binds'
well, it is obvious that it may be moulded to any shape, either alone or mixed with
other compounds.
This sublimate, or the original crystals, may be re-sublimed with or without the
addition of other hydrocarbons approximating thereto, for example, with raw or
refined camphor, by which the melting-point of the mass may be raised and other
properties imparted. I sometimes heat the manufactured product in a closed
vessel to raise the melting- and boiling-points.
I also get rid of impurities as much as possible by washing and careful
.heating.
I find impurities, even in very small quantities, cause considerable variations
in the melting- and boiling-points.
In this way I am able to effect important manufacturing results.
Dated this 28th day of September 1895.
COMPLETE SPECIFICATION.
Improvements in or relating to the Manufacture of
Camphor," and its Treatment.
$$ Artificial
I JAMES CHARLES RICHARDSON of 19 Claremont Square, in the County of
London, N., Electro-chemical Engineer, do hereby declare the nature of this
invention and in what manuer the same is to be performed, to be particularly
described and ascertained in and by the following statement:- 1.
The present invention relates to the manufacture and treatment of the substance"

page_text: commonly known as "artificial camphor," which is produced from turpentine, or
from a similar hydrocarbon oil, by treating the said hydrocarbon with hydrochloric
acid gas.
7
This substance, however, as hitherto produced, has not been suitable for use as
an efficient substitute for the natural gum camphor.
The object of my present invention is therefore to obtain artificial camphor
which will be an efficient substitute for the real article for most of the purposes
for which natural camphor is now employed.
The action of the hydrochloric acid gas upon the turpentine or similar hydro-
carbon, has hitherto been somewhat uncertain, inasmuch as the crystals of artificial
camphor have not been obtained always in the manner and in the quantity
expected.
In the course of my investigations, I have ascertained that much uncertainty in
dealing with the turpentine may be avoided, and to this end I proceed as
follows:-
I partly fill a series of wide mouthed vessels (preferably of stoneware or other
inert material) with good American turpentine, or other suitable isomeric hydro-
carbon oil of the terebene series. These vessels may be of any shape or size,
but about ten imperial gallons capacity each has been found convenient in
practice..
These are fitted with air-tight covers, also of inert material, having inlet and
outlet pipes of stoneware, glass, or lead.
The vessels are arranged in series, and the outlet pipe of the first is connected
with the inlet pipe of the second by india rubber tubing joints, and so on, until a
connected series of from seven to fourteen vessels have been arranged. Each
vessel should be about half filled with turpentine or other suitable hydrocarbon to
be operated upon.
A current of hydrochloric acid gas, mixed with atmospheric air, is then passed
through the inlet and outlet pipes of the vessels and thus over the turpentine or
other hydrocarbon oil in all the vessels in the series; and finally from the last
outlet pipe into a level horizontal main of stoneware, which contains a little
hydrocarbon oil, which serves to take up the last traces of hydrochloric acid gas
from the residual gases, atmospheric air, and aqueous vapour produced before they
are finally discharged into the air. The current of hydrochloric acid gas may be
produced by any method known to chemistry, such as the decomposition of common
salt by sulphuric acid, or from commercial chloride of magnesium decomposed by
sulphuric acid. In this last case, the residue left in the gas-generating retorts can
be commercially utilized for the manufacture of "Epsom salts" (sulphate of
magnesia).
Chloride of manganese (the residues from the chlorine stills used in the manu-
facture of "bleaching powder") may in the same way be utilized as a source of
hydrochloric acid gas.
In some chemical works, where borax and boracic acid are produced from
natural borate of lime, the hydrochloric acid gas may be profitably obtained by
slowly mixing, by means of a syphon, sulphuric acid with strong liquid hydro-
chloric acid. The residual weak hydrochloric and sulphuric acids are most
economically applicable for decomposing natural borate of lime into boracic acid
and gypsum.
The hydrochloric acid gas obtained by the latter process is very pure, and is
produced regularly. The current of mixed hydrochloric acid gas.and atmospheric
air coming
contact with the surface of the hydrocarbon oil in the vessels, causes
a strong chemical reaction and rise of temperature, partly due to the absorption
of chlorine, and partly to oxidation of the oil. The heat of the vessels, however,
should not be allowed to rise above 100° Fahr., or the oil may become unduly
discoloured. The heat may be conveniently regulated to any desired point by
causing a current of cool air or water to circulate outside the apparatus.
After the action has been uninterruptedly carried on for from 12 to 30 hours,

page_text: according to the year's season, the apparatus will quickly cool. When the first
part of the process is known to be finished, the vessels are dismounted and the
covers removed; the hydrocarbon oil will then be found converted into a semi-
solid mass of brownish crystals; in quantity usually from 75% to 80% of the
oil employed.
The contents of the vessels are emptied into filter casks, to allow the superfluous
acid oil to drain and collect, to be treated subsequently, as it still contains
camphor substitute. The nearly dry crystals are then thrown into a large vat of
clear water containing from 1% to 3% of soda carbonate, and there agitated until
all adhering acid has been neutralized.
The material is then put into rapidly revolving centrifugal machines, and weak
soda lye occasionally added until the crystals. are perfectly clean, neutral,
and dry.
The crystals thus obtained now require to be further treated, to render them
an efficient camphor substitute.
The artificial camphor is therefore placed in capacious metal or stoneware stills
fitted with wide condensing tubes at the top, preferably in quantities of from
10 to 15 cwt. at a time. A small proportion, varying from 1% to 3% of
permanganate of soda, is added, or an equivalent quantity of any other well-known
foxidizing re-agent (such as bi-chromate of potassium), but preferably perman-
ganate of soda, on account of cheapness. The whole mass of material is then
subjected to a rapid and direct current of steam at or about a pressure of from
2 to 3 atmospheres. By the combined action of the steam and the oxidizing
re-agent, the artificial camphor is still further oxidized and loses chlorine, which is
taken up by the reduced base and alkali. The whole is at the same time sublimed,
and is condensed together with aqueous vapour in the wide tubes as a brilliantly
white crystalline powder, scarcely distinguishable from refined natural camphor.
This is removed to centrifugal machines, where it is thoroughly dried. It is then
available as flour camphor for most of the purposes to which natural camphor in
this form is applied. It may be pressed into cakes or moulds of any form without
losing colour.
If a thoroughly pure article is required, free from all traces of moisture and
peppermint and lemon oils (which are sometimes produced in small quantity by the
complex re-actions which take place during manufacture), the purified camphor
flour is placed in glass or stoneware vessels, and slowly heated in a bath of oil, or
strong solution of chloride of calcium, to a temperature not exceeding 175° C. by
this treatment, the whole of the moisture, with the small quantities of lemon,
peppermint, and unchanged terebene oils, which may be present, are driven off,
and the artificial camphor enters into tranquil fusion, wholly unchanged, and
without decomposition, and may in this state be cast into any desired mould
or form.
On cooling, the artificial camphor solidifies into a translucent crystalline mass,
resembling "Bell" camphor produced by the sublimation of the natural gum.
In this state, the artificial camphor can, by careful regulation of the heat of the
oil bath above described, be caused to boil, and eventually to entirely sublime,
without decomposition, collecting unchanged in a white concrete crystalline mass.
This last product may take the place of camphor for purposes to which the
natural gum is applied.
In dealing with the residual acid oil which drains from the crystals first formed,
and which still contains artificial camphor, I neutralize the same by soda lye, and
subject it in suitable vessels to cooling in a cold chamber, or otherwise, to nearly
the freezing point (0° C.). This causes a further quantity of crystals to precipitate,
which are drained and dried in the centrifugal machine, and added to those first
produced.
The residual oil, together with all the wash waters used, are pumped into a deep
vat, in which the oil separates from the water by natural gravity. This oil is
transferred to large metal stills with large refrigerating worms, in which it is

page_text: distilled in a current of steam at about 2 atmospheres pressure. The first portion
of oil that comes over has a specific gravity of 930°, which gradually rises to
955 or 960, when the receiver is changed, and what subsequently condenses is
kept apart. The distillate gradually rises in specific gravity to '975, by which
time about 96% of the oil in the still will pass over, leaving about 4% of a dark
tarry matter floating in the still.
All the distilled oil having a specific gravity exceeding 955 is subjected to
refrigeration, as it still contains notable quantities of artificial camphor, which, by
cooling, and the centrifugal machine, can be separated, and this is found to be a
very superior product, when melted and sublimed as above described.
The artificial camphor oil, which may be regarded as a bye-product below a
specific gravity of 955, is an uncrystallizable solution of artificial camphor. It is
a white, refractive, and very aromatic oil, which has been found to be a valuable
solvent for india rubber, gutta percha, and most of the resinous gums used in
varnish making.
It is also a good disinfectant, and has been found valuable as an embrocation in
cases of rheumatism.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I wish it to be understood
that I do not claim broadly the manufacture of artificial camphor from turpentine
and similar hydrocarbon oils by means of hydrochloric acid gas, but I declare that
what I do claim is :-
1. The manufacture of an efficient substitute for natural camphor in the manner
herein described, that is to say, by acting upon turpentine or similar hydrocarbon
with hydrochloric acid and air at a regulated temperature, and treating the crystals
so produced by distillation in the presence of steam and an oxidizing agent, in the
manner set forth.
2. The purification and oxidation of the raw camphor substitute to a marketable
product by distillation in closed vessels in a current of steam, or of steam and air,
with or without the addition of oxidizing re-agents, such as permanganate of soda
or bichromate of soda, substantially as described and set forth.
3. The fractional distillation, in closed vessels, of the residual dark oil, made in
the process, in a current of steam, or of steam and air, with the view to its
purification, and the separation of the dissolved camphor substitute remaining
therein, substantially as above described.
4. The careful heating, melting, and subliming of the purified camphor substitute
in a bath, with the view of eliminating the last traces of moisture and impurities,
and to form the substitute into a solid concrete crystalline mass, resembling refined
natural camphor, substantially as described.
Dated this 30th day of June 1896.
NEWTON & SON,
Agents for the Applicant.