Improvements in the Manufacture of Azo Dyes.
Year: 1891

page_text: Date of Application, 25th Feb., 1891
Complete Specification Left, 18th Nov., 1891-Accepted, 19th Dec., 1891
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Azo Dyes.
I, BENJAMIN WILLCOX of 47 Lincoln's Inn Fields in the County of Middlesex,
Patent Agent do hereby declare the nature of this invention (which has been
communicated to me from abroad by Farbenfabriken vormals Friedrich Bayer
& Company of Elberfeld in the Empire of Germany) to be as follows:-
:-
In the Specification accompanying my application for Letters Patent dated
August 22nd 1890 No. 13235 a process is described for the production of mixed
azo colouring matters which mainly consists in further diazotising colouring matters
resulting from the combination in equal molecular proportions of the tetrazo
compound of benzidine and its analogues with alpha-naphthylamine or alpha-amido-
naphthol-ethers and an oxy-carbon acid, and causing the new diazo compounds
obtained to act upon known dyestuff components. According to that process the
following para-diamines are employed namely:---benzidine, tolidine, diamido-
phenyl-tolyl-, diamido-mono-ethoxy-diphenyl, diamido-mono-ethoxy-phenyl-tolyl,
diamido-phenol-ether, diamido-azo-benzene, diamido-azoxy-benzene, diamido-naph-
thalene, diamido-stilbene, diamido-fluorene, diamido-carbazol, diamido-phenylene-
oxide, diamido-toluylene-oxide, para-phenylen-diamine, benzidine-sulphone, tolidine-
sulphone and the sulpho or carbon acids of these diamines, and from brown to green
black and pure black dyes are obtained.
My foreign correspondents have now made certain improvements in this manufac-
ture whereby valuable results are obtained as hereinafter described.
By means of the process described in my said former Specification a series of
products is obtained which products are insoluble or soluble with difficulty. Similar
products result when the tetrazo compounds of such para-diamines or (as the last
dyestuff component) such amines and phenols are employed as contain no sulpho
groups but the colouring matters thus obtained are now enabled to be converted in
the usual manner into products soluble in water by treating them, when thoroughly
dried, with three parts of fuming sulphuric acid at low temperature. They now
possess the advantage of being capable of dyeing unmordanted cotton with the aid
of common salt in an alkaline soap bath, as well as in a neutral bath.
Colouring matters of the same nature as the foregoing and which likewise enable
cotton to be dyed with common salt in a neutral bath or in an alkaline soap bath
can also be obtained when the mixed dyestuff's (intermediate products) resulting
from equal molecular proportions of the aforesaid tetrazo compounds containing no
sulpho group with salicylic acid or cresol carbon acids and alpha-naphthylamine or
alpha-ainido-naphthol-ether, are sulphurised in the first place and afterwards
diazotised and caused to act upon the various dyestuff components. These new
dyestuff's correspond in their tints to those not derived from sulphurised intermediate
products but possess stronger colouring power and are more fast.
In addition to the mixed salicylic acid and cresol carboxy-acid colouring matters
referred to in the aforesaid former Specification No. 13235 of 1890 the process is
also applicable to other mixed colouring matters namely to those which in place of
the salicylic or cresol carboxy-acid, contain other components such as phenols,
amido-phenols, naphthols, dioxy naphthaline, amines, diamines, amido-naphthols or
the substituted derivatives thereof in the amido residue or the sulpho or carboxy
(carbon) acids thereof. These mixed colouring matters result in the known
manner from equal molecular proportions of a tetrazo compound with the aforesaid
phenols and amines and alpha-naphthylamine or alpha-amido-naphthol-ether and
when further diazotised and united with any dyestuff component can be readily
converted into direct acting colouring matters of the most varied tints for dyein;

page_text: cotton. When the products thus obtained are found to be insoluble they can be
rendered soluble in water by treatment with fuming sulphuric acid. When the
sulpho acids of para-diamine are employed in the preparation of the mixed
substantive azo colouring matters manufactured by my foreign correspondents
superior results can be obtained by further diazotising the said mixed colouring
matters and uniting them with dyestuff components which result from equal
molecular proportions of the tetrazo compound of para-diamine sulpho acids, alpha-
naphthylamine or alpha-amido-naphthol-ether, and a substituted amine (containing
no sulpho group) such as alkyl-naphthylamine, tolyl-naphthylamine, meta-oxy-
diphenylamine or alpha and beta naphthol.
When the sulpho acids of the aforesaid paradiamines are employed for the
production of the new direct dyeing colouring matters, the process can be further
modified by taking amido-naphthol ether or alpha naphthylamine as the second
dyestuff component when the first component consists of alpha-naphthylamine or
alpha-amido-naphthol-ether.
Colouring matters of the following description for example, are thus diazotised
namely benzidine disulpho acid and equal molecular proportions of alpha-naphthyla-
mine and alpha amido naphthol ether.
It matters not which of the groups of mixed colouring matters herein before
specified be subjected to the new process for the manufacture of new mixed dye-
stuffs, the same result being obtained in a general way, new colouring matters of
high colouring power and very darkening or intensifying properties being produced
in all cases.
Tints passing from violet blue, through green to deep blue, black and
black brown are obtained. The naphthol ether colouring matters differ from the
naphthylamine colouring matters by their bluer or greener shade and also partly
possess somewhat stronger colouring power. The process for the manufacture of
the new colouring matters is in a general way similar to that described in my
aforesaid former Specification No. 13235 of 1890. The following are given as
examples of the methods of conducting the operations according to the present
invention the parts being by weight.
Manufacture of a black brown dye by sulphurising the colouring matter obtained
from tetrazo diphenyl and salicylic acid in equal molecular proportions, and two
molecular proportions of alpha-naphthylamine.
About 20 parts of the colouring matter obtained according to the process described
in the aforesaid former Specification No. 13235 of 1890, and represented by the
following equation.
are taken in a thoroughly dry condition and slowly introduced at a temperature
between about 10 and 30 degrees Centigrade into about 60 parts of fuming acid
containing about 20 per cent. of anhydride and allowed to stand until a test portion
forms a clear solution in alkali.
The mass having undergone reaction is poured into water the separated
colouring matter is filtered off and isolated by redissolving in alkali and salting out.
This colouring matter dyes unmordanted cotton in an alkaline or neutral bath, a
black brown.
PRODUCTION OF THE DIAZO COMPOUND OF THE SULPHURISED INTERMEDIATE
PRODUCT FROM EQUAL MOLECULAR PROPORTIONS OF TETRAZO-DIPHENYL,
SALICYLIC ACID AND ALPHA-NAPHTHYLAMINE.
About 487 parts of the mixed salicylic acid, alpha-naphthylamine, tetrazo-
diphenyl colouring matter are slowly introduced into about 200 parts of fumming
sulphuric acid, containing about 20 per cent. of anhydride, at between about 0 and

page_text: THE MANUFACTURE OF COLOURING MATTER FROM EQUAL MOLECULAR PROPOR-
TIONS OF TETRAZO-DIPHENOL ETHER, NAPTHIONIC ACID, ALPHA-NAPHTHYL-
AMINE AND ALPHA-NAPHTHOL-DISULPHO ACID.
About 66 parts of the mixed dyestuff obtained from tetrazo-diphenol-ether,
naphthionic acid and alpha-naphthylamine in equal molecular proportions are
dissolved in alkali cooled to about 0 degrees Centigrade mixed with a solution of
7 parts of sodium nitrite and acidulated. The new diazo compound which is formed
after standing for about 12 hours produces, in acting upon a soda alkaline solution
of about 35 parts of alpha-naphthol-disulphio acid, a dark blue violet.
When, in proceeding as described in the foregoing example, the naphthionic acid
is replaced by an equivalent quantity of alkylised beta-naphthylamine-mono-sulpho
acid; that is to say, by diazotising about 69 parts of the colouring matter obtained
from tetrazo-diphenyl-ether and equal molecular proportions of ethyl-beta-naphthyl-
anine-mono-sulpho acid and alpha-naphthylamine and allowing the diazo compound
so obtained to react upon the acetic acid solution of about 30 parts of dioxy
naphthaline-mono-sulpho acid a grey-black colour is produced.
COLOURING MATTER
FROM EQUAL MOLECULAR PROPORTIONS OF TETRAZO-
ALPHA-NAPHTHOL-MONO-SULPHO ACID, AMIDO-NAPHTHOL-
ETHER AND ALPHA-NAPHTHOL-MONO-SULPHO ACID.
DIPHENYL,
About 62 parts of the mixed colouring matter obtained from tetrazo-diphenyl,
alpha-naphthol-mono-sulpho acid and alpha-amido-naphthol-ether in equal molecular
proportions are dissolved in alkali mixed with a solution of 7 parts of sodium nitrite
and diazotized by acidulating. The diazo compound thus obtained produces, in
acting on a soda alkaline solution of about 26 parts of alpha-naphthol-mono-sulpho
acid, a very dark violet blue.
|COLOURING MATTER FROM EQUAL MOLECULAR PROPORTIONS OF TETRAZO-
STILBENE-DISULPHO ACID, ALPHA-NAPHTHYLAMINE ALPHA-NAPHTHOL AND
ALPHA-NAPHTHOL-MONO-SULPHO ACID.
About 68 parts by weight of the mixed dyestuff obtained from the tetrazo
compound of diamido-stilbene-lisulpho acid, alpha-naphthylamine and alpha-

page_text: naphthol are dissolved in alkali, mixed with a solution of about 7 parts of sodium
nitrite acidulated and allowed to stand for about 12 hours. The resulting diazo
compound in acting on a soda alkaline solution of about 26 parts of alpha-naphthol-
mono-sulpho acid produces a dark grey.
By employing an acetic acid solution of about 30 parts of dioxy-naphthaline-
mono-sulpho-acid in place of the alpha-naphthol-mono-sulpho acid in this example a
black azo dye is obtained. In like manner ethyl-alpha-naphthylamine produces a
brown-black.
COLOURING MATTER FROM EQUAL MOLECULAR PROPORTIONS OF TETRAZO-
STILBENE-DISULPHO ACID, ALPHA-NAPHTHYLAMINE, ALPHA-AMIDO-
NAPHTHOL-ETHER AND TWO MOLECULAR PROPORTIONS OF
NAPHTHOL-MONO-SULPHO-ACID.
ALPHA-
About 72 parts of the colouring matter obtained from tetrazo-stilbene-disulpho acid
alpha-naphthylamine and alpha-amido-naphthol-ether in equal molecular proportions
are dissolved in alkali and the solution is mixed with about 14 parts of sodium
nitrite and acidulated. After standing for about 12 hours the diazo compound
formed is allowed to run into a soda alkaline solution of about 55 parts of alpha-
naphthol-mono-sulpho acid. A very beautiful blue-black dye results.
Dated this 25th day of February 1891.
COMPLETE
SPECIFICATION.
Improvements in the Manufacture of Azo Dyes.
1 BENJAMIN WILLCOX of 47 Lincoln's Inn Fields in the County of Middlesex
Patent Agent do hereby declare the nature of this invention (which has
been communicated to me from abroad by Farbenfabriken vormals Friedrich
Bayer & Co. of Elberfeld in the Empire of Germany) and in what manner
the same is to be performed to be particularly described and ascertained in and by
the following statement :-
In the Specification of Letters Patent No. 13235 granted to me and dated
August 22nd 1890 a process is described for the production of mixed azo coloring
matters which process mainly consists in further diazotising colouring matters
resulting from the combination in equimolecular proportions of the tetrazo com-
pounds of benzidine and its analogues with alpha-naphthylamine or alpha-amido-
naphthol ether and a hydroxycarbonic acid and causing the diazo compounds so
obtained to act upon known dye-stuff components. In the said process the use of
the following paradiamines is prescribed namely:-benzidine, orthotolidine, para-
diamidophenylovthotolyl, paradiamido-orthomonoalkyloxydiphenyl, paradiamido-
ortho-monoalkyloxy-phenylorthotolyl, paradiamido orthodiphenolether, paradiamido-
azo-benzene, diamido-naphthalene (a a) paradiamidostilbene, para-diamido-fluorene,
diamido-carbazol, paradiamido-phenylene oxide, paradiamidotoluylene oxide, para-

page_text: phenylenediamine, the sulphones of benzidine, orthotolidine or diamidophenyl-
orthotolyl and the sulpho acids of these diamines. The dyes vary from brown to
green-black and pure black in colour.
My foreign correspondents have now made certain improvements of considerable
value in this manufacture as hereinafter described.
The products obtained by means of the aforesaid process are either insoluble or
difficultly soluble such products are formel when either the tetrazo-compounds of
the paradiamines or the amines or phenols employed do not contain the sulpho
group, but such colouring matters may be converted in the usual manner into
products soluble in water by treating them in a thoroughly dry state with about
three parts of fuming sulphuric acid at a low temperature. The advantage gained
by this treatment is that dyes are obtained which are capable of dyeing unmordanted
cotton with the aid of common salt both in an alkaline soap-bath and in a neutral
bath.
Colouring matters of the same nature as the foregoing capable of dyeing cotton
with the aid of common salt in a neutral bath or in an alkaline soap bath can also
be obtained from the mixed dye-stufts or intermediate products resulting from the
action of equimolecular proportions of the aforesaid tetrazo compounds in which
there is no sulpho group with salicylic acid and alpha naphtliylamine or alpha
amido naphthol ether by sulphonating and then diazotising and causing the diazo
compound so produced to act upon any of the well known dye-stuff components.
The new products correspond as regards the tints they will produce with those
derived from unsulphonated interinediate products but possess a greater colouring
power and are faster.
The process is also applicable both to the mixed colouring matters derived from
salicylic and cresol carboxylic acids referred to in the aforesaid Specification of
Letters Patent No. 13235% and to other mixed colouring matters namely to such as
those which in place of either salicylic or cresol carboxylic acid contain other
components such as phenol, naphthol, dihydroxynaphthalene, an amine or a sulpho,
or carboxylic acid thereof. These mixed colouring matters are produced in the
known manner from equimolecular proportions of a tetrazo compound of one of the
aforesaid phenols and amines, and of alpha naphthylamine or alpha amido naphthol
ether, and when further diazotised and united with any dye stuff component can be
readily converted into colouring matters capable of dyeing cotton without the aid of
mordants a great variety of shades. The products thus obtained if difficultly
soluble in water can be rendered soluble or more easily soluble by a subsequent
treatment with fuming sulphuric acid.
When the sulpho acids of the paradiamines are employed for the production of
the new direct dyeing colouring matters the process can be further modified by
taking amido naphthol ether or alpha naphthylamine as the second dye-stuff com-
ponent, when the first component consists of alpha naphthylamine or alpha amido-
naphthol ether. In this case colouring matters are diazotised, such as for example,
that formed from benzidine sulpho acid and equi-molecular proportions of alpha-
naphthylamine and alpha amido naphthol ether whichever of the mixed colouring
matters hereinbefore described are subjected to the new process for the manufacture
of new mixed dye-stuffs the same result in general is obtained, dye stuffs being
produced which are of high colouring power and of very dark shades varying from
violet blue through green to deep blueish-black or blackish-brown.
The naphthol ether colouring matters are distinguished from the naphthylamine
dyestuffs by their bluer or greener shades.
The process is effected in general in accordance with the following equation
representing the production of the colouring matter formed by combining tetrazo
diphenyl chloride with one molecular proportion of salicylic acid and one of alpha
naphthylamine, further diazotising the intermediate product thus obtained and
coupling the resulting diazo derivative with an amine or phenol as for example
alphanaphthylamine.

page_text: Manufacture of a blackish-brown dye-stuff by sulphonating the colouring matter
obtained from tetrazo diphenyl and salicylic acid in equi-molecular proportions and
two proportions of alpha naphthylamine."
About 20 parts of the thoroughly dried colouring matter obtained according to
the process described in the aforesaid Specification of Letters Patent No. 132350
and represented by the following formula :-
.
are introduced at a temperature between about 10 and 30 degrees Centigrade into
about 60 parts of fuming sulphuric acid containing about 20 per cent. of anhydride,
and this mixture is allowed to stand until a test portion yields a clear solution when
mixed with soda-lye. After the colouring matter has been sulphonated, the liquid
is poured into water, the separated product is filtered off dissolved in alkali and the
new dye-stuff is then salted out and isolated in the usual manner.

page_text: Production of the diazo compound of the sulphonated intermediate product from
equi-molecular proportions of tetrazodiphenyl, salicylic acid and alpha naphthyl-
amine.
51 parts of the mixed dye-stuff obtained according to the Specification of the
aforesaid Letters Patent No. 13235 from equi-molecular proportions of tetrazo-
diphenyl, salicylic acid and alphanaphthylamine and having the composition:
AT
with a solution in water of about 7 parts of sodium nitrite and the liquid is acidu-
lated with hydrochloric acid. The diazotisation is completed after an interval of
about 12 hours and the mixture may then be directly employed for the manufacture
of dye-stuffs.
THIRD EXAMPLE,
Production of dyes from the diazo compound obtained according to the second
example.
Such a quantity of the diazo compound described in the second example as is
equivalent to 7 parts of sodium nitrite is introduced into a solution in water of
14 parts of salicylic acid in sodium carbonate. The action is complete after the
mixture has been allowed to stand for several days. The dye stuff may be isolated
by filtering off and colours unmordanted cotton a yellowish-brown.
By adding in like manner the said diazo compound to an acetic acid solution
of 106 parts of metaphenylenediamine and allowing the mixture to stand for
about 12 hours a dye-stuff is obtained producing on cotton a blackish-brown
colour.
Greyish-black colouring matters can be obtained by the action in like manner of
the said diazo compound upon a solution of 25 parts of the sodium salt of alpha
naphtholalphamonosulpho acid in the presence of sodium carbonate.
When mixed with 262 parts of the sodium salt of dihydroxynaphthalenemono-
sulpho acid.S in an acetic acid solution in like manner the aforesaid diazo compound
produces a very beautiful Russian green.
When instead of the dihydroxynaphthalene monosulphonate of sodium 36-3 kilos.
of the sodium salt of amidonaphtholdisulpho acid are employed and are caused to
act in like manner in an alkaline solution on the aforesaid diazo compound a
pure green dyestuff is obtained which is very fast in presence of alkalies and in
sunlight.

page_text: 631 parts of the mixed dye-stuff obtained from tetrazoorthodiphenol ether,
naphthylamine monosulpho acid (naphthionic acid) and alpha naphthylamine in
equal molecular proportions and having the composition:
SO,Na
CHN=N-CHNH,
OCH,
are dissolved in alkali; the liquid is then cooled to about 0 degrees Centigrade
mixed with a solution of 7 parts of sodium nitrite, and acidulated. The conversion
into the new diazo compound is completed in about 12 hours. The diazo compound
thus obtained is then added to a solution of 34'8 parts of the sodium salt of alpha
naphtholdisulpho acid S. in the presence of sodium carbonate. As product of its
action a dye stuff is obtained which produces on cotton a dark blueish violet
colour.
A greyish black colour is produced if the naphthylamine-mono-sulpho acid of
the last named example be replaced by an equivalent quantity of alkylised beta
naphthylamine monosulpho acid, that is to say by diazotising 67-8 parts of the
colouring matter obtained from tetrazo orthodiphenolether and equi molecular
proportions of ethylbeta naphthylamine mono sulphonate of sodium and alpha
naphthylamine and allowing the diazo compound thus produced to act on the solution
in water of 26-2 parts of the sodium salt of dihydroxynaphthalene mono sulpho
acid S. in the presence of sodium acetate.
Colouring matter from equi molecular proportions of tetrazodiphenyl, alpha
naphtholmonosulpho acid, amido naphtholether and alphanaphthol monosulpho
63-5 parts of the mixed colouring matter of the composition:
acid.

page_text: obtained from the tetrazo compound of diamido stilbene disulpho acid, alpha
naphthylamine and alpha naphthol are dissolved in alkali and mixed with a solution
of 7 parts of sodium nitrite. The liquid is then acidulated and allowed to stand
for about 12 hours. The resulting diazo compound being allowed to act on a
solution of 246 parts of the sodium salt of alphanaphtholinono sulpho acid in
presence of sodium carbonate gives rise to a dark grey colouring matter of the
formula
By employing an acetic acid solution of 26.2 parts of the sodium salt of
dihydroxynaphthalene mono sulpho acid S. in place of the alphanaphtholmono
sulphonate of sodium of this example a black azo dye is obtained.
In like manner ethyl-alphanaphthylamine produces a brownish-black.
Colouring matter from tetrazo-stilbenedisulpho acid and equi molecular pro-
portions of alpha naphthylamine, ethyl alpha-naphthylamine and alpha naphthol-
disulpho acid S.
65 parts of the mixed dye-stuff obtained from tetrazo stilbene disulpho acid,
alpha naphthylamine and ethyl alphanaphthylamine are diazotised in the usual
manner and caused to act upon 34.8 parts of alpha naphtholdisulpho acid S. in
alkaline solution. The resulting dye which possesses the formula:

page_text: Colouring matter from equimolecular proportions of tetrazostilbene disulpho acid,
alpha naphthylamine, alpha amidonaphthol ether and two molecular proportions of
alpha naphthol monosulpho acid.
66.5 parts of the colouring matter obtained from tetrazostilbene disulpho acid,
alphanaphthylamine and alpha amido naphthol ether in equimolecular proportions
are dissolved in alkali, the liquid is then mixed with a solution in water of 14 parts
of sodium nitrite and acidulated. After standing for about 12 hours the resulting
diazo compound is allowed to run into a solution of 49-2 parts of the sodium salt of
alphanaphtholmono sulpho acid in the presence of sodium carbonate. The resulting
dye-stuff of the formula:
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. The process for converting into soluble dyestuffs, by the treatment with
fuming, sulphuric acid, the insoluble, or difficutly soluble, products which are
obtained according to the Specification of Letters Patent No. 13235", by employing
the following paradiamines, not containing a sulpho group, viz.-benzidine, ortho-
tolidine, paradiamido-phenylorthotolyl, paradiamido ortho-mono alkyloxy-diphenyl,
paradiamido ortho mono-alkyloxyphenylorthotolyl, paradiamido ortho diphenol
ether, paradiamido azo benzene, diamidonaphthalene, (a, as), paradiamidostilbene,
paradiamido-fluorene, diamidocarbazol, paradiamido phenylencoxide, paradiamido
toluylene oxide, paraphenylene diamine, benzidine sulphone, tolidine sulphone,
diamido-phenylorthotolylsulphone, that is to say, the dyestuffs formed, by combining
one molecule of any one of these diamines with one molecule of alpha-naphthyl-
amine, or alphaamidonaphthol ether, and with one molecule of salicylic acid, or
cresol carboxylic acid, further diazotising the products so formed, and coupling the
resulting diazo compounds with one molecule of an amine, or phenol, not containing
a sulpho group.
2. The production of soluble dye-stuffs by treating with fuming sulphuric acid
the so called intermediate products obtained by coupling the tetrazo compounds of
the unsulphonated diamines enumerated in the first Claim with alpha naphthylamine,
or alpha-amidonaphtholether, and with salicylic acid, or cresol carboxylic acid, in
molecular proportions, further diazotising the sulphonated products thus formed,
and combining the resulting diazo compounds with a phenol, or an amine.
3. The manufacture of new mixed colouring matters by combining molecular
proportions of tetrazo-compounds with alpha naphthylamine, or alpha-amido-
naphtholether, and a phenol, naphthol, dihydroxynaphthalene, amine, amidonaphthol,
or sulpho acid of one of the said amines, or phenols, further diazotising the products
thus obtained, and combining the resulting diazo compounds with one, or two,
molecular proportions of a phenol, uaphthol, dihydroxynaphthalene, amine, amido
naphthol, or a sulpho, or carboxylic, acid, of one of the said amines, or phenols.

page_text: 4. The production of soluble dye-stuff's by treating, with fuming sulphuric acid,
the insoluble, or difficultly soluble, mixed colouring matters which do not contain
a sulpho group and which are obtained according to the preceding third Claim.
5. The process for manufacturing soluble colouring matters by treating, with
fuming sulphuric acid, the intermediate products made according to the preceding
third Claim by combining molecular proportions of the tetrazo compound of an
unsulphonated diamine with alpha naphthylamine, or alpha amidonaphthol-ether,
and with one of the following compounds, viz. :-phenol, naphthol, dihydroxy-
naphthalene, amine, amido naphthol, by further diazotizing the sulphonated
products and by combining the diazo derivatives thus obtained with one, or two,
molecular proportions of a phenol, naphthol, dihydroxynaphthalene, amine, amido
naphthol, or a sulpho, or carboxylic, acid of the last named amines, or phenols.
6. As new manufactures, the dye-stuffs obtained according to the preceding
Claims one, two, three, four and five.
Dated this 17th day of Navamhar 1801