DD271115A1 - PROCESS FOR THE PREPARATION OF A CATIONIC OPTICAL BRIGHTER OF THE 1,3-DIPHENYLPYRAZOLIN SERIES - Google Patents

Abstract

The invention relates to a process for the preparation of the optical brightener whose cation corresponds to the formula I. It is prepared starting from 1- & 4- (b-hydroxyethylsulfonyl) -phenyl! -3- & 4-chlorophenyl! -Pyrazoline via the stages of the sulfuric acid ester and the vinylsulfonyl compound by reacting the latter with dimethylaminoethanol and subsequent quaternization by means of dimethyl sulfate according to the invention in a two-phase mixture of water / chlorobenzene prepared without isolation of intermediates. Formula I

Description

Cl- O

-SO ₂ -C ₂ H ₄ -OC ₂ H ₄ -N (CH ₃ )

equivalent.

Characteristic of the well-known Stend.es of technology

It is known that the compound of formula I by addition of dimethylaminoethanol to the vinylsulfonyl compound of the formula

Cl

-SO ₂ -CH = CH ₂

and subsequent reaction with, for example, dimethyl sulfate. The compound of formula II, in turn, from the corresponding ß-hydroxyethylsulfone of the formula

Cl

over the resulting by esterification with sulfuric acid sulfuric acid ester of the formula

-SO ₂ -CH ₂ -GH ₂ -OSO ₃ H

receive.

According to the known processes, it is necessary to isolate both the sulfuric acid ester of the formula IV as the alkali salt and the vinylsulfonyl compound of the formula II (DE-AS 1413329, UE-OS 2142564) and the addition compound of the Vinylsulfonylverbindiing and aminoalcohol (DE-AS 1469222). For further implementation of the isolated vinylsulfonyl compound, it is also necessary to dry them and apply in the further synthesis of a high excess of amino alcohol.

Z.el the invention The aim of the invention is to overcome the deficiencies resulting from the prior art. Presentation of the essence of the invention

It was therefore the task of developing a manufacturing process with which the stated goal is achieved. According to the invention, this object is achieved in that, starting from the hydroxyethylsulfone of formula III in a first known manner by introducing it into concentrated sulfuric acid produces the sulfuric acid ester of formula IV, the so-obtained reaction solution sorfjnn soint dropped while stirring in a two-phase mixture of chlorobenzene and aqueous sodium hydroxide so that the temperature does not exceed 4O ⁰ C, then adjusting a pH of about 10 to about 11 and heated to 50 to 6O ⁰ C, forming the vinylsulfonyl compound of formula II, which passes into the chlorobenzene. After completion of the reaction, the jhlorbenzenische phase is separated from the aqueous phase, in the chlorobenzene phase dimethylaminoethanol in a molar ratio of 1: 1 to 1.02, based on the starting material of formula III, and in the presence of NaOH as a catalyst at a pH vcn about 9th heated to temperatures between 50 and 60 ⁰ C. After the reaction and cooling is quaternized with dimethyl sulfate. The resulting compound of formula I is deposited as methosulfate and extracted by the addition of water. It is expedient to use an amount of water such that the aqueous solution obtained directly after separation from the chlorobenzene phase can be used directly as a type of brightener solution.

The erfindungsc emäße process has the advantage over the prior art that it works without isolation of intermediates.

embodiment In a stirred flask, 30 ml of concentrated sulfuric acid are introduced and 9.1 g of 1- [4 '- (ß-hydroxyethylsulfonyl) - with stirring.

phenyl-3- [4 "-chlorophenyl] -pyrazoline is added slowly, stirring is continued for 15 hours.

Subsequently, the reaction solution is concentrated to a mixture of 300 ml of water, 150 ml of chlorobenzene and 50 ml Sodium hydroxide solution added dropwise with stirring. The temperature should not exceed 40 ° C. With further concentrated caustic soda

is adjusted to pH 11 and then stirred at 50 to 60 ° C for three hours. The vinylsulfonyl compound formed thereby passes into the chhrbenzenische phase. This is then separated from the aqueous phase and stirred with 2.25 g

Dimethylaminoethanol added. It is then heated to 40 ° C and added 0.6 ml of concentrated sodium hydroxide solution. Subsequently

is heated to 50 to 60 ° C and stirred for two hours.

After cooling to 3O ⁰ C 3ml dimethyl sulfate are added and stirred for thirty minutes at this temperature

held. By adding 70 ml of water, the precipitated methosulfate dissolves and is prepared as an aqueous solution of the finished

Brightener separated from Chlo'benzen. Yield: 70% of lightener solution and 78% of theory (based on Ausgjngssubstanz)

Claims (1)

Claim: A process for the preparation of a cationic optical brightener of the 1,3-diphenylpyrazoline series, the cation of the formula Cl (I) corresponds, from 1- (4 '- (ß-hydroxyethylsulfonyl) -phenyl] -3- [4 "-chlorophenyl] -pyrazolin via the stages of the sulfuric acid ester and the vinylsulfonyl compound, characterized in that, without isolation of intermediates in an initially known manner the 1- [4 '- (ß-hydroxyethylsulfonyl) -phenyl] -3- [4 "-chlorophenyl] -pyrazolin reacted with concentrated sulfuric acid, the reaction solution thus obtained is then added dropwise with stirring in a two-phase mixture of chlorobenzene and aqueous sodium hydroxide so that the temperature does not exceed 40 ⁰ C, then adjusts a pH of about to about 11 and heated to 50 to 6O ⁰ C, then separating the chlorobenzene phase from the aqueous phase containing the resulting vinylsulfonyl chlorobenzene phase with dimethylaminoethanol in a molar ratio of 1 : 1 to 1.02, based on the starting material, in the presence of catalytic amounts of sodium hydroxide at temperatures between 50 and 60 ⁰ C, after U quaternized by the addition of dimethyl sulfate, then mixed with water, the compound of formula I is extracted as methosulfate, and finally the aqueous phase is separated from the chlorobenzene. Field of application of the invention The invention relates to the preparation of a cationic optical brightener of the 1,3-diphenylpyrazoline series, the cation of the formula