Sampling of flammable and hazardous reagents (1)

Alkyl organometallic (lithium, sodium, potassium, magnesium, zinc, aluminum, etc.

One of the problems facing the laboratory is how to take samples safely

1.

Syringe withdrawal is limited to less than 100mL

(1) Preparation

(1) Observe whether the reagent in the bottle is turbid or not.

(2) The complete package should include: ① Outer packaging

The lower edge of the aluminum outer rim needs to be fastened inward to the lower ring of the glass bottle threaded mouth, otherwise, when the plastic bottle cap is unscrewed, the entire lid may be opened, which is very dangerous

(3) Prepare a balloon filled with inert gas and attach a needle to keep the pressure balance inside and outside the bottle

(4) Use a dry syringe, including an inner plug

Figure 23-18 Outer packaging

Figure 23-19 Sealing parts of bottle mouth

Figure 23-20 Unqualified packaged products (1)

Figure 23-21 Unqualified packaged products (2)

(2) Safety operating procedures

(1) Place the reagent bottle on the table steadily

(2) Unscrew the bottle cap

(3) Insert the balloon into the inner membrane to keep the pressure balance inside and outside the bottle

(4) Insert a dry syringe into the inner membrane

(5) The index finger and the middle finger are against the enclosure of the upper mouth of the cylinder.
The two fingers can be above the enclosure, as shown in Figure 23-22, or one finger on top and bottom, as shown in Figure 23-23.
In this way, the stroke of the piston in the syringe can be controlled, and then the inner piston of the syringe can be pulled by the thumb and ring finger to the required volume scale
.

Figure 23-22 Two fingers can be above the enclosure

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Figure 23-23 One finger on the top and bottom of the enclosure

(6) Immediately pour the reagent in the syringe into the reaction flask or the dropping funnel
.

(7) Empty syringes must be quenched with alcohol before they can be thrown into the specified special collection bucket
.

(3) Matters needing attention

(1) Do not emptied the reagent bottle in your hand, so as not to fall off and cause a fire
.
There have been accidents: the bottle emptied and slipped, and the reagent splashed on the clothes caused a fire all over the body
.

(2) When extracting, do not pull out the plunger of the syringe uncontrollably, otherwise it is easy to pull out and cause a fire.
The method in Figure 23-24 is extremely wrong
.

Figure 23-24 Wrong operation

Case study

On December 29, 2008, in the chemistry laboratory of a branch campus in the United States, a 23-year-old female research assistant who had only been working for two months after graduating from the university was using a syringe to extract tert-butyl lithium.
The base lithium was spilled, evaporated, and burned in the air, and unfortunately knocked over a bottle of organic solvent next to it, causing a fire
.
Although he wore protective glasses and nitrile gloves, he did not wear flame-resistant work clothes and was wearing a chemical fiber sweater (equivalent to solid gasoline).
40% of his body area including his hands and arms was burned.
Although he was rescued vigorously, this The research assistant tragically passed away 18 days after the accident
.
The school was fined US$31,875 by the California Occupational Safety and Health Administration for failing to keep up with the usual training and protective measures.
The school felt that it was mismanaged and expressed its approval and punishment
.
This incident caused a sensation in American universities and related industries, and the response was great
.

Related link: Safety regulations for anhydrous and oxygen-free operation