Preparation and application of naphthol AS-G_Kain Industrial Additive

[Background and Overview]^[1][2]

Nathophenol is the coupling component of ice dyes and is mainly used for cotton fiber, viscose It can be used as a primer for dyeing and printing of viscose fibers, and can also be used to prepare intermediates for fast pigment dyes and organic dyes and pigments. The phenol molecule does not contain water-soluble groups such as sulfo or carboxyl groups, but it is soluble in alkaline media. Practical norophenols are about6oThe remaining species, these naphthol-like products are usually collectively referred to as naphtholASClass. Naphthol ASYes 2–Hydroxynaphthalene –3 span>–Formic acid (abbreviation 2, 3–acid)It is produced by the condensation reaction of aniline and aniline in a chlorobenzene solution using phosphorus trichloride as a catalyst. The finished product is often beige or reddish. Content is about98.0% , can meet the requirements of various quality standards, but users have higher requirements for the quality of naphtha, especially the appearance of the product, so products made through direct condensation often cannot meet the requirements of domestic users and foreign trade exports, which also affects the its applications and sales.

NaphtholAS-GAlso known as NaphtoAS-G、4,4′-double(N-acetoacetyl span>)O-toluidine , 3 ,3′-Dimethyl-4, 4′二(N-acetoacetylbenzidine. C.I.Azoic coupling components、 C.I.37610). This product is a naphthol with a biphenyl structure. Naphtholvalue Less than3, the reaction temperature is10C below, the reaction solution turns blue to starch potassium iodide test paper, and the reaction time is 1-3hours until the diazotization reaction is complete, add an appropriate amount of urea to the reaction solution, stir and decompose Excess sodium nitrite until the reaction solution does not change color on the starch potassium iodide test paper to obtain a diazonium salt solution;

(2) Use alkali solution to completely dissolve the coupling componentsR2, due to the equimolar coupling of the azo component and the diazonium salt, it is preferredR2equimolar to the diazo component Compare. Filter to remove mechanical impurities and cool the filtrate to 5-10℃, at 10-15minAdd steps(1)in the diazonium salt solution, keep the temperature at5-10℃,pH The value is 7.5-10, continue the reaction, and use the penetration circle method to detect it until the The nitrogen salt disappears completely and a coupling liquid is obtained; the coupling componentR2is acetoacetanilide, or o-chloroacetoacetanilide, or2 , 4 –Dimethylacetoacetanilide, or o-methoxyacetoacetanilide, or naphtholAS-G, or naphthylAS-IRG , or phenylpyrazolone, or p-chlorophenylpyrazolone, or p-tolylpyrazolone, or2,4-Dichlorophenylpyrazolone, or2,4-xylpyrazolone;

(3) Add an appropriate amount of abietic acid sodium salt solution to the coupling solution and continue stirring at room temperature for at least 0.5hours, then add an appropriate amount of barium chloride aqueous solution , continue stirring at room temperature for at least 0.5hours, then add Heat until the temperature is65℃ or above, stir again for at least 0.5hour or more, filter while hot, wash the filter cake with water, and 80C and below, drying is performed to obtain a photooxidation-resistant yellow monoazo organic pigment.

The pigment has good comprehensive properties such as light resistance, heat resistance and migration resistance, and can be used for outdoor advertising, automotive paint and high-end inkjet printing Applications such as inks that require high light resistance of organic pigments.

【Preparation】^[¹^]

Method 1： With3 ,3′- span>Dimethylbenzidine and diketene are used as raw materials and can be produced by condensation in hydrochloric acid and xylene solutionNaphthylAS-G[1] .

Method 2:With3,3′- Methylbenzidine, under the catalysis of triethanolamine, in xylene medium, reacts with ethyl acetoacetate 130 ～140 The reaction can be carried out at ℃NaphthylAS-G[1].

[Main reference materials]

[1] Practical Fine Chemical Dictionary

[2] Su Qiong, Wang Yanbin. Research on the purification process of naphthol AS[J]. Applied Chemical Engineering, 2003, 32(5): 27-29.

[3] Zhang Xiaodong; Liu Xin; Sun Deshuai. A light-resistant yellow monoazo organic pigment and its preparation method CN200510045497.X, application date 2005-12-03