With the continuous development and growth of Yadong group, the products produced and operated by Yadong group have expanded from direct dyes, acid dyes and reactive dyes to dye intermediates. As an employee of Yadong chemical industry group, he should have some basic knowledge about dye intermediates.
Dye intermediates are one of the intermediates, including pharmaceutical intermediates and dye intermediates.
1、 What is dye intermediate
The simple organic raw materials (such as benzene, naphthalene, anthracene, etc.) are used in the chemical reaction process to produce the organic materials which are more complex than the original structure, but have no dye characteristics. For example: p-nitroaniline, DSD acid, 2-naphthol, H acid, 1-aminoanthraquinone, bromamine acid.
2、 Source of raw materials for dye intermediates
There are many kinds of raw materials for dye intermediates production, but they are mainly divided into inorganic raw materials and organic raw materials.
Commonly used inorganic raw materials are acids: sulfuric acid, fuming sulfuric acid, nitric acid, hydrochloric acid and chlorosulfonic acid.
Alkali: sodium hydroxide, sodium carbonate, sodium bicarbonate, ammonia water, etc.
Salts: sodium chloride, sodium sulfate, etc.
Besides aromatic compounds such as benzene, naphthalene and anthracene, there are aliphatic compounds in common organic materials. Aliphatic compounds mainly include methanol, ethanol, ethylene oxide, formaldehyde, acetic acid, acetic anhydride, phosgene, etc.
Benzene, naphthalene, anthracene and other aromatic compounds are mainly obtained from coking by-products and petrochemical industry.
In particular, Wuhai Yadong Chemical Co., Ltd. of our group is located in Wuhai City, which is the main production base of coal coking chemical industry, which is very beneficial to our production of naphthalene intermediates.
3、 Common chemical reactions in the production of dye intermediates
1. Nitration: under the action of nitrating agent such as nitric acid, the reaction of hydrogen atom in organic molecule replaced by nitro is called nitration, and the product is called nitro compound.
2. Sulfonation: under the action of sulfonating agent (such as sulfuric acid, fuming sulfuric acid, chlorosulfonic acid), the reaction of sulfonic acid group replacing hydrogen atom in organic compound molecule is called sulfonation reaction. The resulting product is called a sulfonic acid compound.
3. Amination: there are two ways to produce aromatic amines.
① Reductive method: reductive method is used to reduce nitro compounds to obtain amines.
② Ammoniation: amines produced by replacing hydroxyl, chlorine and sulfonic groups with amines are called ammoniation.
4. Hydroxylation: hydroxylation refers to the reaction of introducing hydroxyl into aromatic molecules. It is also made in many ways. We mainly use alkali fusion method
Alkali fusion method: the reaction of sodium sulfonate and caustic soda melting at high temperature, the conversion of sulfonic acid group to hydroxyl group is called molten alkali reaction.
4、 Our group currently produces and will produce in Wuhai the intermediate simple synthesis method.
1. Tocopherol: 2-naphthol through sulfonation, neutralization, stratification, distillation ammoniation, acidification, filtration and other processes.
2. J-acid: through sulfonation, hydrolysis, filtration, concentration, alkali melting, acidification, filtration and other processes.
3. H-acid: sulfonation, nitration, denitrification, neutralization, reduction, filtration, segregation, filtration, alkali melting, acid filtration and other processes of refined naphthalene.
4. G salt: 2-naphthol is sulfonated, salted out, filtered and washed.
5. R-salt: g salt filtrate is subject to salting out, filtration, washing and other processes.
6. R-Acid: g salt through alkali fusion, neutralization, ammoniation, acidification, filtration, washing and other processes.
7. Para ester: it is produced by sulfonation, dilution, filtration, reduction, condensation, filtration, drying, esterification and other processes.
8. Amino c acid: sulfonation, nitration, dilution, denitrification, salting out, reduction, concentration, acid analysis and other processes of refined naphthalene.
Technical center Zhang Chaoshui