Production of a New Basic Yellow Colouring Matter.
Year: 1894

page_text: Date of Application, 12th Nov., 1894
Complete Specification Left; 12th Aug., 1895-Accepted, 14th Sept., 1895
PROVISIONAL. SPECIFICATION.
Production of a New Basic Yellow Colouring Matter.
We, ARTHUR GEORGE GREEN F.I.C., F.C.S., of 13 Kings Drive, Heaton
Moor, Stockport, and ROBERT JANSEN Ph.D. of 16 The Grove, Victoria Park,
Manchester, Chemists to The Clayton Aniline Company Limited, Aniline Dye
Manufacturers of Clayton, in the County of Lancaster, do hereby declare the
nature of our invention to be as follows:-
In 1888 one of us (v. A. G. Green, Journal Chem. Soc. 1889, 55, 230) made the
.bservation that the trialkylammonium salts of dehydrothiotoluidine are valuable
basic yellow coloring matters which dye silk and tannin-mordanted cotton bright
greenish shades similar to auramine. This discovery was also made independently
at about the same time by L. Cassella & Co. and formed the subject of Letters
Patent No. 6319 and 14884 of 1888. The present invention relates to the
preparation of lower homologues of the above colours by alkylation of the lower
homologue of dehydrothiotoluidine which is obtained according to the method of
the Societe Anonyme des matieres colorantes de St. Denis by heating a mixture
of 1 mol. of paratoluidine and rather more than 1 mol. of aniline with sulphur
(4 atoms) until evolution of hydric sulphide has ceased (r. French Patent 216086,
Sept. 12th 1891). The product of this reaction, after distillation. and
crystallisation from amyl alcohol shows itself to be a definite chemical compound
to which the name 66
Dehydrothioaniline
It
may be provisionally given..
crystallizes in small prismatic crystals and has the constant melting point 151°
(according to the above Patent the melting point is 154°).
"
For production of the alkylated derivatives the base or one of its salts is heated
with an alkyl haloid such as methyl bromide or benzyl chloride or with a mixture
of an alcohol and a mineral acid. As an illustration of the general method of
procedure the following example may be given :-
25 lbs. of dehydrothioaniline are mixed with 5 gallons of methyl alcohol and
3 gallons of hydrochloric acid (40% HCl)
and the mixture is heated under pressure in an autoclave for 12 hours at 160°-
170° C. The product is dissolved in hot water filtered from insoluble matter
(dimethyl derivative) and the new coloring matter is precipitated from the filtrate
by the addition of salt. It forms a yellow powder of very similar properties to
thioflavine T but dyes a somewhat greener shade of yellow. Its constitution is
probably represented by the formula:-

page_text: Production of a New Basic Yellow Colouring Matter.
We ARTHUR GEORGE GREEN and ROBERT JANSEN, both of Clayton,
Manchester, Chemists 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:―
In 1888, one of us (vizt. A. G. Green-Journ. Chem. Socy. 1889, 55. 230) made
the observation that the trialkylammonium salts of dehydrothiotoluidine are
valuable basic yellow colouring matters which dye silk, and tannin-mordanted
cotton bright greenish shades, similar to auramine. This discovery was also made
independently at about the same time by L. Cassella & Co. and formed the subject
of Letters Patent No. 6319 and 14884 of 1888. The present invention relates to
the preparation of lower homologues of the above colours by alkylation of the
lower homologue of dehydrothiotoluidine which is obtained according to the method
of the Societé Anonyme des matières colorantes de St. Denis by heating a mixture
of one molecular proportion of paratoluidine and rather more than one molecular
proportion of aniline with sulphur (4 atoms) until the evolution of hydric sulphide
has ceased (vide French Patent 216086 September 12th 1891). The product of
this reaction, after distillation and crystallisation from amyl-alcohol is a definite
chemical compound to which the name "Dehydrothioaniliue may be given. It
crystallises in small prismatic crystals and has the constant melting point
151° Centigrade; (according to the above French Patent the melting point is
154° Centigrade).
"
According to our present invention for the production of alkylated derivatives,
the said base (dehydrothioaniline) or one of its salts is heated with an alkylhaloid
such for example as methyl-bromide or benzyl-chloride or with a mixture of an
alcohol and a mineral acid. As an illustration of the general method of procedure
the following example may be given but we do not limit ourselves to the precise
details of this example.
EXAMPLE I.
25 lbs. of dehydrothioaniline are mixed with 5 gallons of methyl alcohol and
3 gallons of hydrochloric acid (40 per cent. HCl) and the mixture is heated under
pressure in an autoclave for 12 hours at from 160° to 170° Centigrade. The
product is dissolved in hot water filtered from insoluble matter and the colouring
matter is precipitated from the filtrate by the addition of salt. It forms a yellow
powder of very similar properties to thioflavine T but dyes a somewhat greener
shade of yellow. Its constitution is probably represented by the formula :—

page_text: Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. The manufacture of alkylated derivatives of the thiobase, herein before termed
dehydrothioaniline, by heating the said thiobase (or one of its salts) with an
alkylhaloid, or with a mixture of an alcohol and a mineral acid under pressure.
2. The manufacture of a new basic yellow colouring matter according to the first
example hereinbefore given.
3. The manufacture of a new basic yellow colouring matter according to the
second example hereinbefore given.
4. As new articles of manufacture, the new basic colouring matters produced by
the process herein before stated, or by any other process affording the same result."
Dated this 12th day of August 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.