Highly toxic and highly toxic substances

1.

Dimethyl sulfate is a highly toxic substance, and quenching is required for both discarded reagents and post-reaction treatments

The excess dimethyl sulfate in the reaction solution can also be treated with alkali, or it can be trapped in the column or eluent by column chromatography, and then quenched with alkali

Other highly toxic or highly toxic esters can also be treated with this method

2.

1) Sodium cyanide , potassium cyanide and zinc cyanide

Cyanide is mostly highly toxic.

(1) Fe ²⁺ method

To a solution of the CN ^- weakly alkaline solution is added 20% ferrous sulfate or of FeSO _.

(2) Oxidation method

First oxidize cyanide to cyanate with sodium hypochlorite :

NaCN+NaClO=NaOCN+NaCl

Then it is further oxidized to carbon dioxide and nitrogen:

2NaOCN+3NaClO+H ₂ O=3NaCl+2NaOH+N ₂ ↑+2CO ₂ ↑

The overall response is as follows:

5NaClO+2NaCN+H ₂ O=5NaCl+2NaOH+N ₂ ↑+2CO ₂ ↑

Adjust pH>9, add fresh NaClO solution with high effective chlorine concentration, 1mol cyanide needs about 5L 10% NaClO solution

(1) Use starch potassium iodide test paper to test, but need to adjust pH≤9

2I ^- + ClO ^- + 2H ⁺ = the I ₂ + CI ^- + H ₂ O

(2) C (the CN ^- ) concentration of test papers (C (the CN ^- ) concentration of <100 mg / L)

2) Trimethylsilyl cyanide (TMSCN), cyanamide (NH ₂ CN), cyanogen halide (CNX)

Although some related cyanides are not listed in the highly toxic list, they are highly toxic or have other hazards.

Trimethylsilyl cyanide (TMSCN): It reacts with water to generate hydrocyanic acid .

Cyanamide (NH ₂ CN): The original packaging of the large barrel has undergone a polymerization explosion

H ₂ N-CN+H ₂ O=H ₂ N-CO-NH ₂

Cyanogen halides (BrCN, ICN, FCN): When exposed to heat or water, it will release highly toxic hydrogen cyanide gas

3.
Arsenic trioxide

Arsenic trioxide is the most commercially valuable arsenic compound and the main arsenic chemical starting material
.

Quench the arsenic trioxide by adding calcium oxide (or calcium hydroxide) and sodium carbonate (or sodium bicarbonate) into the arsenic trioxide aqueous solution to form calcium arsenite [Ca ₃ (AsO ₄ ) ₂ ] and calcium arsenate [Ca ₃ (AsO ₄ ) ₂ ] Such precipitation can greatly reduce its toxicity
.

Other arsenic-containing waste liquid treatment principles: use the precipitation and adsorption of hydroxide, such as the magnesium salt dearsenic method, add magnesium salt to the arsenic-containing waste liquid, adjust the pH to 9.
5 to 10.
5, and generate magnesium hydroxide precipitation; The adsorption of magnesium hydroxide and arsenic compounds, stirring, standing overnight, and draining the waste liquid, the separated precipitate can be treated together with the precipitation of the heavy metal salt
.

4.
Other highly toxic substances and cytotoxic substances

The "Catalogue of Toxic Chemicals" currently published by the country only has 184 highly toxic chemicals.
In fact, these are some of the bulk chemicals that are common on the market and are mostly known to the public.
For the chemical field, including hypersensitivity cell poisons, There are countless highly toxic chemicals, so it cannot be considered that compounds that are not listed in the National Catalogue of Toxic Chemicals are not highly toxic compounds
.

The quenching methods of various highly toxic substances can be based on their different chemical properties, especially their active groups and overall structure.
Appropriate methods should be adopted to change their active groups or destroy their overall structure, which is conservative and reliable.
The method is to use Fenton reagent for oxidation quenching or incineration disposal
.

Related links: Exothermic compounds violently in contact with water