IMPROVEMENTS IN PRODUCING YELLOW COLOURING MATTER SUITABLE FOR DYEING AND PRINTING
Year: 1884

page_text: I, JOHN ERSKINE of 151 St Vincent Street Glasgow in the County of Lanark,
North Britain, Solicitor do hereby declare the nature of the said invention for
IMPROVEMENTS IN PRODUCING YELLOW COLOURING MATTER SUITABLE FOR DYEING
AND PRINTING to be as follows :-
"
"
This Invention relates to the production of yellow colouring matter suitable for
dyeing and printing.
The Invention consists in taking about 22 lbs weight of the Sulphate of
Benzidine which is mixed with 330 lbs weight of water when there is added
thereto 44 lbs of hydrochloric acid of the strength corresponding to 21° Baumè.-
This mixture is azotised by adding to it about 51%, lbs weight of Nitrite of Soda.-
The resulting Tetrazodiphenyl solution is then slowly discharged, (under the
influence of strong agitation,) into a solution of 11 to 22 lbs of natural or artificial
Salicylic or oxybenzoic acid,-this solution having been mixed in 88 lbs of hydrate
of soda and 550 lbs of water.-Instead of using the salicylic acid for the purposes
of this Invention a like quantity of Phenol or Cresol may be substituted.
From the foregoing treatment there results a precipitate which is almost
insoluble in water. This precipitate is then separated and washed until it is
neutral. The residue is then fit for use in dyeing or printing-It' dyes unmor-
daunted cotton in a boiling soap bath a fast sulphur color.

page_text: I, JOHN ERSKINE of 151 Saint Vincent Street, Glasgow, in the County of
Lanark, North Britain, Solicitor do hereby declare the nature of the said invention
for IMPROVEMENTS IN PRODUCING YELLOW COLOURING MATTER SUITABLE FOR'
DYEING AND PRINTING and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
This Invention relates to the production of yellow colouring matter suitable for
dyeing and printing.
The Invention consists in taking about 22 lbs weight of the Sulphate of Benzidine
which is mixed with 330 lbs. weight of water when there is added thereto 44 lbs. of
Hydrochloric Acid, of the strength corresponding to 21° Baumè.
This mixture is azotised by adding to it about 5 lbs weight of Nitrite of Soda.
The resulting Tetrazodiphenyl solution is then slowly discharged (under the
influence of strong agitation) into a solution of 11 to 22 lbs of natural or artificial
Salicylic or Oxy-benzoic Acid, the solution having been mixed in 88 lbs of hydrate
of soda and 550 lbs. of water..
Instead of using the salicylic acid for the purposes of this Invention, a like
quantity of Phenol or Cresol may be substituted.
From the foregoing treatment there results a precipitate which is almost insoluble
in water.
The precipitate is then separated and washed until it is neutral.
The residue is then fit for use in dyeing and printing.
It dyes unmordaunted cotton in a boiling soap bath a fast sulphur colour.
Having now, particularly described and ascertained_the_nature_of_the_said.
Invention and in what manner the same is to be performed, I declare that what
I claim is
The production of a yellow colouring matter by or through the action of
Tetrazodiphenyl on Oxy-benzoic Acid and in particular on Salycilic Acid or Phenol
or Cresol, all in manner substantially hereinbefore described.
Dated this Seventeenth day of March 1885.