N. Introduction to N-dimethylformamide:

Dimethylformamide (DMF) is a transparent liquid, which is miscible with water and most organic solvents. It is a common solvent for chemical reactions. Pure dimethylformamide has no smell, but industrial grade or deteriorated dimethylformamide has fishy smell because it contains impurities of dimethylamine. The name comes from the fact that it is a dimethyl substitute of formamide (the amide of formic acid), and both methyl groups are located on the n (nitrogen) atom. Dimethylformamide is a polar (hydrophilic) aprotic solvent with high boiling point, which can promote the progress of SN2 reaction mechanism. Dimethylformamide is made from formic acid and dimethylamine. Dimethylformamide is unstable in the presence of strong bases such as sodium hydroxide or strong acids such as hydrochloric acid or sulfuric acid (especially at high temperatures) and hydrolyzes to formic acid and dimethylamine.

N. Physicochemical properties of N-dimethylformamide:

Appearance and properties: transparent colorless liquid

Density: 0.948g/mlat 20 ° C

Boiling point: 153 ° C (lit.)

Melting point: -61 ° C

Flash point: 136 ° f

Refractive index: n20/d 1.430 (lit.)

Water solubility: soluble

Storage conditions: complete package, light loading and unloading, ventilated warehouse, away from open fire, high temperature, and stored separately from oxidant and acid

Steam density: 2.5 (vs air)

Steam pressure: 2.7 mm Hg (20 ° C)

Purpose:

Dimethylformamide is most widely used in amide solvents. It is mainly used as solvent for polyacrylonitrile fiber spinning. As a gas absorbent in petrochemical industry, it is used for selective absorption of acetylene and separation and purification of butadiene. It is used as solvent in artificial leather production. It is used as stationary phase in gas-liquid chromatography. It is used to synthesize Chlordimeform in pesticides. In medicine, it is used to synthesize sulfadiazine, doxycycline, cortisone, vitamin B6, etc. In addition, dimethylformamide is an aprotic polar solvent, which is an excellent solvent for many organic synthesis reactions.

[hazardous characteristics] it may cause combustion and explosion in case of open fire and high heat. It can react violently with concentrated sulfuric acid and nitric acid and even explode.

【 first aid method 】

Skin contact: take off contaminated clothes immediately, and wash with a large amount of flowing water for at least 15 minutes. Seek medical attention.

Eye contact: lift the eyelids immediately and wash thoroughly with a large amount of flowing water or normal saline for at least 15 minutes. Seek medical attention.

Inhalation: quickly leave the site to a place with fresh air. Keep respiratory tract unobstructed. If breathing is difficult, give oxygen. If breathing stops, give artificial respiration immediately and seek medical advice. Ingestion: rinse with water, drink milk or egg white, and seek medical advice.

Fire fighting measures: first cut off all fire sources and wear gas masks and gloves. Rinse with water, and the diluted sewage is put into the wastewater system.

[emergency treatment]

Evacuate the personnel from the leakage contaminated area to the safe area quickly, isolate them and strictly restrict their access. Cut off the fire source. It is recommended that emergency treatment personnel wear self-contained positive pressure respirators. Do not touch the leakage directly. Cut off the source of leakage as far as possible. Prevent from flowing into restricted spaces such as sewers and flood discharge ditches. Small leakage: adsorb or absorb with sand or other non combustible materials. The floor can also be sprinkled with soda ash, then washed with a large amount of water, diluted with washing water and put into the waste water system. Massive leakage: build a dike or dig a pit for collection. Cover with foam to reduce steam disaster. The steam is cooled and diluted with spray water. Transfer to tank car or special collector by pump, recycle or transport to waste treatment site for disposal. Other protection: smoking, eating and drinking are prohibited at the work site.