Production process and product standard of 2-methyl-5-nitroaniline

6.
Production process

1) Salt formation

Put 98% concentrated sulfuric acid from the metering tank into the nitrification pot, cool the temperature to 0-25°C, add o-methylaniline under stirring , maintain this temperature, and stir until it is completely dissolved
.

2) Nitrification

Turn on the freezer, cool the salt-forming material to about -10°C, and add 98% nitric acid under stirring to carry out the nitration reaction
.

3) Dilution

Put water in the dilution pot first, add the nitrified materials under stirring, and control the temperature at about 70℃.
After the materials are added, the temperature will be lowered to 25℃
.

4) Hydrolysis

Put ammonia water in the hydrolysis pot first, and slowly add the material filter cake when the temperature is 55-65°C
.

7.
Product Standard

8.

The content is determined as follows:

Weigh 2g of the sample dried at 50～60℃ to a constant weight (weigh to 0.
001g), put it into an 800mL beaker, add 25mL concentrated hydrochloric acid and 200mL distilled water, and add 200mL distilled water after it is completely dissolved (with slight heat if necessary) And 20mL potassium bromide
.

In the formula: V——the volume of sodium nitrite solution consumed by the sample, mL;

V ₁ ——The volume of sodium nitrite consumed in the blank experiment, mL;

c——The molar concentration of sodium nitrite solution for titration, mol/L;

m——the mass of the sample, g
.

9.

Mainly used for dyeing and printing of cotton fabrics, coupled with Naphthol AS or AS-D to dye bright red (ie flag red), and can also be used for dyeing silk, viscose and nylon fabrics
.

10.
Security measures

(1) The raw material o-toluidine is highly toxic, and its toxicity is similar to that of aniline.
It can be poisoned by breathing or skin absorption
.

(2) The products are packed in iron drums lined with plastic bags and stored in a ventilated and dry place
.