Year: 1894

page_text: Date of Application, 23rd July, 1894
Complete Specification. Left, 22nd. Apr., 1895-Accepted, 24th May, 1895
I, OLIVER IMRAY, of No. 28. Soutliampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, do hereby declare the nature of this
invention to be as follows:-
The manufacture of a-naphtholmono sulphonic acid has hitherto been carried
out chiefly in two ways, namely:
1) by boiling the diazo compound of naphthionic acid; this method is
disadvantageous as it gives, an unsatisfactory yield of naphthol sulphonic acid, and
the operation must be carried out in considerable.dilution, so that large quantities
of liquid are necessary; thus the method can only be employed in. cases where the
dilute solution of the acid can be used directly for the manufacture, of: colouring
matters;.
2). on by heating naphthionate of sodium with caustic soda, in closed vessels,
(German Patent 46307) this method gives a better yield than the former, but the
reaction does not take place smoothly, because other bodies are formed as, well; as
the acid desired, apparently dioxy-naphthaline and naphthol...
The, following, new and simple method for manufacturing a naphtholmono-
sulphonic acid 1. 4 is an improvement in both directions as a product of great
purity is obtained in an almost quantitative yield; it starts from the easily
obtainable a-naphtholcarbonate which, by suitable treatment with sulphonating
agents, in distinction to a-naphthol, is almost exclusively sulphonated in the
4 position
a-naphtholcarbonate, which has not hitherto been described, is formed by
treating a dilute alkaline a-naphthol solution with phosgene.
The process is as follows :--
Phosgene gas is led into a solution of 60 kilos. a-naphthol in 60 kilos. caustic
soda of 40° Bé. and 1000 litres of water at ordinary temperature.
The carbonate is at once precipitated as a sandy powder, and the precipitation
increases as the phosgene is absorbed by the liquid.
The transformation is completed when the distinctly alkaline liquid contains no
naphthol in solution. This point is usually reached when, from 23. to. 24 kilos. of
phosgene have been absorbed; theory requires 21 kilos..
The a naphthalcarbonate is filtered, washed and dried... When pure, it forms.a
white crystalline powder, not easily. soluble in. alcohol, easily soluble, in benzene.
This substance, when twice crystallised from alcohol, melts at 129° to 130° C. By.
boiling with strong caustic soda it is converted into. naphthol; it. is more stable
towards dilute acids.

page_text: MANUFACTURE OF THE DISULPHONIC ACID OF THE Carbonate.
The a naphthol carbonate disulphonic acid, from which is obtained 1.4 a naph-
tholdisulphonic acid by decomposition, is formed by dissolving the carbonate in
sulphuric acid of 66° Bé. or in monohydrated sulphuric acid at ordinary temperature.
The best proportions for manufacturing are the following.
50 kilos. carbonate are dissolved by stirring thoroughly at a temperature
of 10° to 20° C. in 150 kilos. of monohydrate. The carbonato dissolves slowly;
after 12 hours the solution is, as a rule, complete and then the formation of the
disulphonic acid of the carbonate is completed. If the temperature of the
sulphonation mixture rises above 20° C., the yield of the acid desired is considerably
diminished; at 40° C. a development of gas can be noticed-a sign of beginning
decomposition. This decomposition of the disulphonic acid of the carbonate
already formed is accompanied, by a further sulphonation of the decomposition
product, apparently forming a-naphtholdisulphonic acid 1. 2. 4.
The melt is poured on to 300 kilos. of ice and then 60 kilos. of salt are added to
the solution (which has a volume of about 350 litres) by means of which the
sulphonic acid of the carbonate is almost completely precipitated in a crystalline
state, and can be separated from the strongly acid solution by filtering and
pressing.
MANUFACTURE OF a-NAPHTHOLSULPHONIC ACID 1. 4.
In order to convert it into the 1.4 acid, the disulphonic acid of the carbonate is
dissolved in water and the solution is heated to 60° to 70° C. until the effervescence
of the carbonic acid ceases. The solid sodium salt can then be made in the usual
way, by neutralising with lime and treating with soda.
For the purpose of making azo colouring matters it is not absolutely necessary
to decompose the disulphonic acid of the carbonate; as it is at once transformed
into the naphtholmono sulphonic acid under the influence of or by contact with
diazo compounds.
Dated this 23rd day of July 1894.
ABEL & IMRAY,
Agents for the Applicant.
Manufacture of a Naphtholmonosulphonic Acid 1.4 from
Naphtholcarbonate.
α
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent 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 :-
· The manufacture of a-naphtholmono sulphonic acid has hitherto been carried out
chiefly in two ways, namely:-
11) by boiling the diazo compound of naphthionic acid; this method is
disadvantageous as it gives an unsatisfactory yield of naphthol sulphonic acid,
and the operation must be carried out in considerable dilution, so that large
quantities of liquid are necessary; thus the method can only be employed in cases
where the dilute solution of the acid can be used directly for the manufacture of
colouring matters;
2) or by heating naphthionate of sodium with caustic soda in closed vessels
(German Patent 46307) this method gives a better yield than the former, but the

page_text: reaction does not take place smoothly, because other bodies are formed as well as
the acid desired, apparently dioxynaphthaline and naphthol.
The following new and simple method for manufacturing a naphtholmono-
sulphonic acid 1.4 is an improvement in both directions, as a product of great
purity is obtained in an almost quantitative yield; it starts from the easily
obtainable a-naphtholcarbonate which, by suitable treatment with sulphonating
agents, in distinction to a-naphthol, is almost exclusively sulphonated in the
4 position.
a-naphtholcarbonate, which has not hitherto been described, is formed by
treating a dilute alkaline a-naphthol solution with phosgene.
The process is as follows:-
--
Phosgene gas is led into a solution of 60 kilos. a-naphthol in 60 kilos. caustic
seda of 40° Bé. aud 1000 litres of water at ordinary temperature. The carbonate
is at once precipitated as a sandy powder, and the precipitation increases as the
phosgene is absorbed by the liquid. The transformation is completed when the
distinctly alkaline liquid contains no naphthol in solution. This point is usually
reached when from 23 to 24 kilos. of phosgene have been absorbed; theory
requires 21 kilos.
The a-naphtholcarbonate is filtered, washed and dried. When pure it forms a
white crystalline powder, not easily soluble in alcohol, easily soluble in benzene.
This substance, when twice crystallised from alcohol, melts at 129° to 130° C. By
boiling with strong caustic soda it is converted into naphthol; it is more stable
towards dilute acids.
MANUFACTURE OF THE DISULPHONIC ACID OF THE CARBONATE.
The a-naphthol carbonate disulphonic acid, from which is obtained 1.4 a-naph-
tholdisulphonic acid by decomposition, is formed by dissolving the carbonate in
sulphuric acid of 66° Bé. or in monohydrated sulphuric acid at ordinary temperature.
The best proportions for manufacturing are the following:
50 kilos. carbonate are dissolved by stirring thoroughly at a temperature of
10° to 20° C. in 150 kilos. of monohydrate. The carbonate dissolves slowly;
after 12 hours the solution is, as a rule, complete and then the formation of the
disulphonic acid of the carbonate is completed. If the temperature of the
sulphonation mixture rises above 20° C. the yield of the acid desired is considerably
diminished; at 40° C. a development of gas can be noticed-a sign of beginning
decomposition. This decomposition of the disulphonic acid of the carbonate
already formed is accompanied by a further sulphonation of the decomposition
product, apparently forming a-naphtholdisulphonic acid 1. 2. 4.
The melt is poured on to 300 kilos. of ice and then 60 kilos. of salt are added
to the solution (which has a volume of about 350 litres) by means of which the
sulphonic acid of the carbonate is almost completely precipitated in a crystalline
state, and can be separated from the strongly acid solution by filtering and
pressing.
MANUFACTURE OF a-NAPHTHOLSULPHONIC ACID 1. 4.
In order to convert it into the 1. 4 acid, the disulphonic acid of the carbonate
is dissolved in water and the solution is heated to from 60° to 70° C. until the
effervescence of the carbonic acid ceases. The solid sodium salt can then be made
in the usual way, by neutralising with lime and treating with soda.
For the purpose of making azo-colouring matters it is not absolutely necessary

page_text: Having now particularly described and ascertained the nature: of: my said inven-
tion and in what manner the same is to be performed. I declare that what I
claim is :
Manufacture of a-naphthol sulphonic acid 1.4 by treating anaphtholcarbonate
with sulphuric acid and then heating the disulphonic acid of the carbonate thus
formed with water.
ABEL & IMRAY,
Agents for the Applicant.