DE116415C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

It was shown in patent specification 112177 that the alkyl esters of aromatic sulfonic acids with ammonia or primary, secondary and tertiary bases react to form the sulfonic acid salts of alkylated bases and not with formation of the corresponding sulfamides and alcohol. It was therefore tried to to transfer the reaction to the alphyl esters of the aromatic sulfonic acids. In in fact it was shown that z. B. the sulfonic acid esters of fluorescence when heated the bases of the fatty series and the aromatic series are able to react in this sense; there are z. B. in treating the p-toluenesulfonic acid ester of the fluorescence with hydrochloric acid dimethylamine and similar tetramethylrhodamine and some rhodol were obtained in smooth yield. The carboxylic acid esters of the fluorescence do not show this property; the sulfonic acid esters behave similarly to fluorescein chloride; before the latter process, the aforementioned means a technical one Progress than it leads to rhodamine in a cheaper way and also the production the rhodole. enables. .

The sulfonic acid esters of fluorescence are not yet known; They can be easily obtained by heating fluorescein, or better still, fluorescein sodium with the chlorides of the aromatic sulfonic acids, ζ. B. p-toluenesulfonyl chloride to about 140 ^° ; the sulfonic acid esters are also formed in aqueous solution. They are quite indifferent bodies, similar in properties to fluorescein chloride. They are almost colorless, insoluble in water and alkalis, very sparingly soluble in alcohol, ether, petroleum ether, more easily in hot benzene, from which they can be crystallized. On saponification with alcoholic potash, fluorescein is regenerated.

Example 1.

A mixture of 376 Th en eil dry fluorescein and 382 parts ρ ~ toluenesulphochloride few hours is heated to 140 ^0th The Reactionsproduct is leached with water and dilute sodium hydroxide solution and in the dry state can either be used directly to the melt or after recrystallization from benzene, wherein in the heat, it is rather easily soluble (FP 163-165 ^0).

An intimate mixture of 128 parts Toluolsulfosäureester, 128 parts of a hydrochloric acid dimethylamine, 80 parts of zinc chloride, 60 parts of lime is heated with stirring at 220 some time ⁰ until the color intensity of the melt no longer increases. The melt is boiled with soda solution for a long time in a stream of steam, and the solution is filtered. The filtrate is made acidic with hydrochloric acid and the hydrochloric acid tetramethylrhodamine is precipitated from it with table salt. This still contains small amounts of dimethylrhodol, which can easily be separated from the tetramethylrhodamine with boiling sodium hydroxide solution.

Example 2.

If you replace the hydrochloric acid in Example 1 Dimethylamine by hydrochloric acid diethylamine is widely obtained under the same conditions less tetraethylrhodamine, but diethylrhodol in good yield, so this Process is suitable for the production of the rhodol.

With hydrochloric acid monoethylamine one obtains not only symmetrical diethyl rhodium but also monoethyl rhodol, which is easy in alkali hydrate, more difficult in acids with reddish yellow fluorescence solves. Acetic acid causes precipitation of the monoäthylrhodolbase in from alkaline solution Form of a flaky, brick-red precipitate.

With hydrochloric aniline or Aniline and p-toluenesulfonic acid fluorescence semester the result is a dye analogous to violamine, which, like the latter, can be easily sulphurised. Of course, the fluorescein esters of other aromatic sulfonic acids show ζ. Β. the Fluorescent benzenesulfonic acid ester, quite the same behavior; the ρ-toluenesulfonic acid ester proves to be particularly useful only because of its easy accessibility.

Claims (1)

Patent claim: Process for the preparation of phthalene dyes, consisting in converting fluorescein into the esters of aromatic sulfonic acids and these with primary or secondary fatty or aromatic bases for reaction brings.