Process for Obtaining New Dyestuffs of the Phthaleïne Series.
Year: 1897

page_text: Date of Application, 17th May, 1897-Accepted, 26th June, 1897
COMPLETE SPECIFICATION.
Process for Obtaining New Dyestuffs of the Phthaleïne Series.
I, HAROLD IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the.
County of London, Chartered Patent Agent, do hereby declare the nature of this
invention (which has been communicated to me from abroad by The Basle Chemical
Works Bindschedler, of Basle, Switzerland, Manufacturers) and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement:-
My foreign correspondents have found that the dialkylamidooxybenzoylbenzoic
acids can be easily combined with resorcinol to dyestuffs which in the form of their
28 kilos. of dimethylamidooxybenzoylbenzoic acid are heated on the water-bath with
14 kilos. of resorcino! in 180 kilos. of monohydrated sulphuric acid and 180 kilos. of
water, until a sample no longer increases in intensity of colour in warm water. The
mixture is then poured into 1000 litres of water and heated for a longer time. After
cooling, the separated crystals are filtered and washed with water. By dissolving in
alkali precipitating and recrystallizing from dilute alcohol the compound can be
obtained pure. The dimethylrhodol hydrochloride obtainable in this way forms
beautiful hard crystals which are sparingly soluble in cold water.
In alcohol they
dissolve with a yellow-red colour. On the addition of ammonia a brilliant green
fluorescence is developed. With alkalies the base forms salts soluble in water.
By etherifying agents the rhodol is converted into ethers. For this purpose 30 kilos..
of its hydrochloride, for example, are heated for several hours in 80 kilos. of alcohol
and 75 kilos. of monohydrated sulphuric acid, until all is dissolved. The solution is
poured into water, the base is precipitated and is converted into the hydrochloride,
which is purified by recrystallisation from water containing hydrochloric acid. The
ether in the form of its hydrochloride dissolves in water with a yellow-red colour.
It differs from rhodol in the solubility of its hydrochloride in water and in its incapacity
to form with alkalies salts soluble in water. The base of the ether is soluble in alcohol
and ether. Its alkaline alcoholic solutions fluoresce shewing a beautiful yellowish
green. Strong sulphuric acid dissolves it with a yellow colour. From dilute alcohol
it can be obtained in the form of hard crystals.
The diethyl-products behave similarly to the dimethylrhodol and its ether
respectively as described above.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:-
1. A process for obtaining dyestuffs of the phthaleine series consisting in condensing
the dialkylamidooxybenzoylbenzoic acids with resorcinol substantially in the manner
described.
2. A process for converting the dyestuffs obtained according to Claim 1 into
derivatives soluble in water, consisting in heating them with an alcohol and an acid
substantially in the manner described.

page_text: 3. As new industrial products the dyestuffs soluble in water obtained according to
Claims 1 and 2 from dimethylamidooxybenzoylbenzoic acid or diethylamidooxybenzoyl-
benzoic acid.