CS225698B1 - Preparation of 2-cyan-4-nitro-4-//methoxycarbonylethyl-n-cyanethyl/-amine/-1,1-azobenzene - Google Patents

Description

The present invention relates to a method for carrying out the coupling in the preparation of 2-cyano-4-nitro-4 - [(N-methoxycarbonylethyl-N-cyanethyl) -amino] -1,1-azobenzene of the formula ## STR3 ##

0 ₂ N __

CoH.COOCHn c ₂ h ₄ cn This color pigment, after wet dispersion grinding with a suitable dispersant, is used primarily for dyeing and printing polyester fibers.

The present dye is prepared by allowing a solution of the diazonium salt, prepared by diazotizing 2-cyano-4-nitroaniline with nitrosylsulfuric acid, dissolved in concentrated sulfuric acid, to flow onto the ice and allowing the resulting aqueous diazonium salt solution to be allowed at 0-5 ° C. C slowly N-methoxycarbonylethyl-N-cyanethylaniline *

A disadvantage of this process is that the pigment being formed grows into coarser crystals and crystalline conglomerates which enclose a part of the hitherto uncoupled components and thus prevent their intermolecular contact. This unfavorable course is manifested primarily by a decrease in pigment yields and on the duration of the reaction.

These drawbacks are eliminated by the method of coupling of diazotized 2-cyano-4-nitroaniline with N-methoxycarbonylethyl-N-cyanethylaniline in aqueous acidic medium to 2-cyan-4-nitro-4 - [(N-methoxycarbonylethyl-N-quaggtyl) -amino] -1,1-azobenzene of formula

0 ₂ H ^N = ^N - / ^< OV- N ^C 2 ^H 4 ^C00CH 3 \ / \ _f c ₂ h ₄ cn

225 698

225 698 according to the invention, in that the coupling is carried out in the presence of an alkylpolyglycol ether-based surfactant of the formula RO-GHgCHgOj ^ - CHgCHgOH, where R is alkyl Ο θ až to Ο a and η · 1 to 25 and / or alkylpolyglycol ether sulphate; its sodium salts of the general formula

RO-ÍCHgCHgOj ^ j ^ SO CHgCHgO + "wherein R is a C ^ _Q to CGQ and η - 1 to 20 in an amount of 0.5 to 20% by weight of pigment expected. Preferably, the alkyl polyglycol ethers may be used, wherein R j C l Gan »3.4 and 5 alkylpolyglykoletersírovou acid or its sodium salt, wherein R is C _l2 yes 4 or can be mixed with alkyl polyglycol alkyl polyglycol ether sulfates in a ratio of 1 with the first

The advantage of this procedure is that the addition of a surfactant can influence the course of the coupling in the sense that the product formed falls in single crystals, without the formation of coarser clumps and crystalline conglomerates. This not only leads to a faster coupling, but also strongly influences the yields of the resulting product. While in surfactant-free coupling, yields range from 75 to 82% of pigment theory, and yields to 52% of pure pigment theory, yields in the presence of surfactant increase to 90 to 97% of pigment theory with yields of up to 80% of pure pigment theory. colorimetrically. In addition to the advantage of substantially increasing yields by the use of a surfactant, there is also considerable energy savings and a reduction in wear of the grinding apparatus with easier and faster dispersion grinding of the pigment paste Example.

46.4 g of N-methoxycarbonylethyl-N-cyanethylaniline are dissolved in 168 g of acetic acid. Weigh 800 g of ice into the reaction vessel as a charge and add a solution of 4 g of a 1: 1 mixture of alkyl polyglycol ether with alkyl polyglycol ether sulfate dissolved in 50 ml of water. A diazotizing mixture of 2-cyano-4-nitroaniline in sulfuric acid is allowed to be added as quickly as possible to the draft, with vigorous stirring, so that the temperature does not exceed 0 ° C. Simultaneously and with a small delay, as soon as 10 to 25% of the total amount of the concentrated diazotization mixture in the master is present, a rapidly prepared solution of the passive component in acetic acid is admitted so that it is already in the master before the last amount of diazonium compound. At -15 to 0 ° C, the coupling is generally complete in 10 to 30 minutes. To improve the filtration, stir the reaction mixture for an additional 8-16 hours, dilute to about 3000 ml with water, filter, and wash the cake with water until neutral. The pigment paste is further processed by a finishing treatment conventionally performed on disperse dyes.

Claims (4)

Preparation method 2-cyano-4-nitro-4 - [(N-methoxycarbonylethyl-N-cyanethyl) amino] -1,1-azox. (V®), CqH.COOCH, benzene of formula (II)--ACTχACT · 7ACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACTACT ACT-- _kop N-methoxycarbonylethyl-N-cyanethylaniline in an aqueous acidic medium, characterized in that the coupling is carried out in the presence of an alkylpolyglycol ether-based surfactant of the formula RO-CGHgCHgOj ^ - CHgCHgOH, where R is alkyl až to Ο ^ θ and η 1 to And / or an alkylpolyglycoleteric acid or a sodium salt thereof of the general formula SO-CH 2 CH 3 CH 2 CH 2 CH 2 CH 2 O 2, wherein R is alkyl of C 1 to C 20 and 1 to 20, in an amount of 0.5 to 20% by weight of the expected pigment. 2. The process of claim 1 wherein an alkylpolyglycol ether is added to the reaction mixture 225 Formula RO-ÍCHgCHgOj -CHgCHgOH ^, where R is alkyl _Ο χ2 n - 3, 4 to 5 3. Process according to claim 1, characterized in that the reaction mixture is added sulfuric acid alkyl polyglycol »or its sodium salt of formula R-0- _{(CH2 CH2} 0) _{n-CH 2} CH ₂ 0 ⁺ S0j, wherein R is alkyl C12 and _n4 , 4. The process of claim 1, wherein a 1: 1 mixture of alkyl polyglycol ether with alkyl polyglycol ether sulfate or a free acid thereof is used.