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The molecular formula of 2,4-dichlorobenzaldehyde (2,4-dichlorobenzaldehyde) is C 7 H 4 Cl 2 O, the molecular weight is 175.
0, and the structural formula is
1.
Product performance
White prismatic crystals; melting point 74.
5℃; easily soluble in methanol , absolute ethanol , ether and acetone , but insoluble in water; can be oxidized to the corresponding acid, and can undergo nucleophilic addition to the aldehyde group with ammonia and its derivatives Into a reaction
.
2.
Production principle
2.
4-Dichlorotoluene undergoes a-chlorination under light to generate the corresponding a-dichloro product, which is then hydrolyzed to obtain the product
.
3.
Process flow
4.
Technical formula (kg/t)
5.
Main equipment
Chlorination kettle, absorption tower, hydrolysis kettle, steam distillation kettle, rectification tower, condenser, water separator, storage tank
.
6.
Production process
500kg of 2,4-dichlorotoluene was added to the chlorination reactor, the temperature was raised to 120°C, and the light was irradiated, and chlorine gas was started to flow
.
The reaction exotherms and the temperature gradually rises
The hydrolysis kettle was stirred and heated to 125°C, 1.
5kg of Zn3(PO4)2 was added, the temperature was controlled at 125-130°C, and 90kg of water was slowly added dropwise to the kettle
.
After dripping, cool to 90°C, slowly add 450kg of 20% soda ash solution, heat to reflux for 2.
7.
Product Standard
8.
Quality inspection
(1) Preparation of hydroxylamine solution
.
Take 20 g of recrystallized hydroxylamine hydrochloride, add 40 mL of water to dissolve it, and then dilute to 400 mL with ethanol
(2) Determination
.
Accurately weigh 1.
8g of the sample, put it into a 250mL glass stopper bottle, add 75.
0mL of hydroxylamine solution, and stopper
.
Maintain at room temperature for 1h
.
Then, add bromophenol blue test solution as an indicator, titrate with 0.
5 mol hydrochloric acid to the blue-yellow end point, or indicate with an acid meter, and titrate to pH 3.
4
.
A blank experiment was carried out simultaneously as above
.
Calculate the percentage content as follows:
In the formula: c——molar concentration of hydrochloric acid, mol/L;
V 1 ——The volume of hydrochloric acid consumed in the blank experiment, mL;
V 2 ——The volume of hydrochloric acid consumed when titrating the sample, mL;
G——The mass of the sample, g
.
9.
Product use
Used in organic synthesis, as a dye intermediate for the synthesis of acid lake blue A, reactive brilliant blue K-FGR and other dyes
.
10.
Security measures
(1) The production equipment should be airtight, and the chlorinating operators should be strictly trained before they can work
.
(2) Packed in plastic bucket, sealed and kept away from light
.
Related links: Product performance and production principles of glyoxal
