Junior High School Chemistry: The main points of the use of common chemical reagents for junior high school chemistry!

Junior High School Chemistry: The main points of the use of common chemical reagents for junior high school chemistry!

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The scope of hazardous chemicals in chemicals

The characteristics of the hazardous chemicals are attributable to:

1. Explosive and unstable substances. Such as thick peroxide, organic peroxide, etc.

2. Oxidized substance. Such as oxidized acids, hydrogen peroxide also belongs to this category.

3. Combustic substances. In addition to flammable gases, liquids, and solids, it also includes substances that produce combustible materials in the tide. Such as alkaline hydrogenation, calcium carbide, and spontaneous combustion substances such as white phosphorus.

4. Toxic substances.

5, corrosive substances. Such as acid, alkali, etc.

6, radioactive substances.

Laboratory reagent storage and use rules

Storage and use of laboratory reagents:

1. The flammable and explosive test agent should be stored in the iron cabinet (more than 1mm wall thickness), and the top of the cabinet has a ventilation. It is strictly forbidden to store bottle flammable liquids greater than 20L in the laboratory. Flammable and explosive drugs should not be placed in the refrigerator (except the explosion -proof cabinet refrigerator).

2. After mixing with each other or contacting each other, two or more compounds with fierce reactions, combustion, explosions, and toxic gases can be generated as non -compatible compounds and cannot be mixed. This compound system is mostly strong oxidized substances and reduction substances.

3. Corrosive reagents should be placed in plastic or enamel disks or buckets to prevent accidents caused by bottle rupture.

4. Pay attention to the period of storage of chemicals. Some reagents will gradually deteriorate and even form hazards during storage.

5. Drug cabinets and reagent solutions should avoid direct sunlight and heat sources close to heating. The reagent required to avoid light should be packed in a brown bottle or wrapped in black paper or black cloth in the dark cabinet.

6. Find the label drop on the reagent bottle or it is to be blurred. Reagents without labels or labels must be treated carefully as dangerous items. Do not throw them casually, so as not to cause serious consequences.

7. The positioning of chemical reagents is placed, after use, after use, and saving use, but the extra chemical reagent is not allowed to return to the original bottle.

Common poisoning symptoms and protection knowledge

1. chlorine

It is mainly poisoned by the respiratory tract and skin mucosa. After inhalation, it immediately causes the symptoms of cough, breath, chest tightness, nasal congestion, and tears. In severe cases, bronchitis, chemical pneumonia and toxic pulmonary edema may occur. Aquatic solution also has corrosion.

Salvation: 1. The indoor ventilation is good, and the mask is brought during operation. Inhale 2 % soda water steam.

2. Carbon monoxide and gas

Entering the body through the respiratory tract, combined with hemoglobin and other iron -containing containing iron in the blood, so that hemoglobin loss of oxygen transmission is dizzy, nauseous, and weak; consciousness disorder occurs during middle poisoning; Breathing stopped and died.

Cure: 1. Move the patient to the fresh air, pay attention to thermal insulation; 2. Those who stop the breathing immediately perform artificial respiration and give oxygen with 5-7 % carbon dioxide; 3. Those with respiratory failure occur at the same time.

3. hydrogen sulfide

Strong neurotoxicity, smell of stinky eggs, loses alertness because it is easy to cause smell fatigue, which causes dizziness, headache, nausea, and vomiting during acute poisoning; shortness of breathing when severe poisoning, suddenly losing consciousness and death.

Salvation: 1. The indoor ventilation should be good, and I feel that they leave the scene immediately in the timely; 2. Rinse with 2 % soda water when the eyes are stimulated, and apply saturated boric acid liquid and olive oil when the eyes are stimulated.

4, sulfur dioxide

Inhale from the respiratory tract, it has a strong stimulating effect on the mucous membrane, causing conjunctivitis, tears, runny nose, dry pharyngeal, and pain; severe poisoning can produce throat dumb, chest pain, dyspnea, throat edema, and suffocation.

Salvation: 1. Immediately leave the scene and breathe fresh air. If you are found to be swollen, you should transmit oxygen; 2. Take sodium carbonate or sodium lactate to treat acid poisoning; 3. Rinse 2 % soda water when the eyes are stimulated.

5. Nitrogen's oxides (NO, NO2)

Through the respiratory tract to the deep respiratory organs, it may cause various degrees of bronchitis, pneumonia, and emphysema. In severe cases, it may cause lung torch. Due to damage to the nervous system, it quickly suffocated to death when inhaling high concentration.

Cure: 1. Immediately leave the scene, keep absolutely quiet, and breathe fresh air; 2. Early vein injection of 50 % glucose 20-60ml; 3. Symptoms of symptomatic treatment.

6, ammonia

It can invade the human body from the respiratory tract, digestive tract and skin mucosa. Strongly stimulate your eyes, tears, cough, and hoarse. 0.45g/m3 contacts 30 minutes to endanger life.

Salvation: 1. indoor ventilation, a mask or stopping breathing when operating ammonia or thick ammonia water; 2. Those who inhaled poisoning immediately leave the scene; those who eat poisoning are cautious, and those who touch the skin are washed with water or dilute acetic acid.

7, methanol

Rebelling poisoning through the respiratory tract and skin. Inhale poisoning damage to the nervous system, causing optic nerve diseases; accidentally taking poisoning cause nausea, vomiting, the whole body is green, and the severe cases quickly stop breathing and died.

Salvation: 1. The ventilation should be good, and the poisoned person is moved to the fresh air;

8. Benzene and its homes

Poisoning is mainly through respiratory tract and skin infiltration. Acute poisoning will be intoxicated, and then red, dizziness, headache, vomiting, and even muscle spasm and coma die; chronic poisoning damage to hematopoietic, nervous system, nasal cavity, gum bleeding, liver, kidney damage, and weakness. Salvation: 1. When used, it should be well ventilated; 2. Try to replace it with other non -toxic or low -toxic solvents; 3. Those with acute poisoning apply artificial respiration to absorb oxygen.

Common safety protection and emergency measures for inorganic acids

1. Sulfuric acid

Safety protection measures: When the respiratory system protection-when the concentration in the air exceeds the standard, we must wear anti-virus masks. When rescue or evacuation of emergency situations, wearing positive pressure self-sufficient respirators should be worn; eye protection-chemical safety protection glasses; physical protection-- Wearing rubber pH protection clothing; hand protection-wearing rubber protective gloves; others-cannot pour it into the water. Smoking, eating and drinking water are strictly prohibited. Shower dressing after work. Maintain good hygiene habits. In the high concentration area, there should be monitoring.

Emergency measures: emergency measures-inhalation of acid mist should be immediately separated from the scene, rest, semi-straight three-dimensional position, artificial respiratory and medical care must be performed; after skin contact, it should be removed from polluted clothes, rinsed with a lot of water, and gives medical care; Rinse your mouth by mistake, drink a lot of water, don't vomit, and give medical care. Fire protection method: Forbidden water, use dry powder, carbon dioxide, sand.

2, nitric acid

Safety protection measures: When the respiratory system protection-when the concentration in the air exceeds the standard, we must wear anti-virus masks. When rescue or evacuation of emergency situations, wearing positive pressure self-sufficient respirators should be worn; eye protection-chemical safety protection glasses; physical protection-- Wearing rubber-resistant pH protection clothing; hand protection-wearing rubber protective gloves; other-workplace is strictly prohibited from smoking, eating and drinking water. Shower dressing after work. Maintain good hygiene habits. In the high concentration area, there should be monitoring.

Emergency measures: emergency measures-immediately leave the scene to fresh air, keep quiet and warm. Rinse a lot of water for more than 15 minutes in the eyes, and the skin is infected with a large amount of water rinse; if there is burns, you should seek medical treatment immediately. Fire protection method: not burning. Cut off the qi source. Spray water -spray cooling container. Move the container from the fire to the open area.

Introduction and general operation of typical drama drugs

1. Organic tin compound

Organic tin compounds are metal organic compounds formed by the direct combination of SN and C elements. Tong type RNSNX4-N (n = 1-4, R is alkyl or aromatherapy). There are two types of alkyl tin compounds and aromatherapy. Its basic structure has one replacement body, second replacement body, three replacement body, and fourth replacement body (referring to the number of R). Tiexane tin mainly damages the hepatobiliary system; titane and tetraxane tin mainly causes nervous system damage. 10-20%of tin yields are used to synthesize organic tin compounds.

The main damage of organic tin compounds to organisms is:

The central nervous system can cause leukemia edema, cell energy, the inhibitory effect of the pantage and lymphic system, the inhibitory effect of the thymus and lymphadenopathy, the hormone secretion inhibitory caused by the inhibitory of the cellular and hyperlipidemia. For human toxicity, local stimulation of the skin, respiratory tract, and cornea, through the skin or cerebral edema, it can cause whole body poisoning and even death. In 1958, France caused 10%of the mortality (referred to as the Study Agricultural Incident) due to the treatment of skin diseases with Sanyi.

General operation:

(1) Operation with protective glasses, masks, gloves, white coats, and ventilation cabinets. [When conditions permit, it is best to wear an isolation respirator, wear a jacket -like adhesive poison jacket, and wear rubber gloves. .

(2) The most important application of organic tin in organic synthesis should be Stille Coupling, which can cover almost half of the catalytic coupling reactions. Stille is also a pioneer of catalytic catalytic. (The biggest disadvantage of this reaction is the toxicity of the tin);

Secondly, some organic tin reagents can be used as a selective free radical reducing agent for multi -energy -aggressive compounds, and the effect is very good. [For Stille Coupling, after the reaction, it is directly concentrated or simply extracted. This is the most common wrong operation. Environmental pollution. The reasonable operation is to add a saturated KF aqueous solution or a PY-HF solution, stir at least one hour, and then perform conventional post-treatment and purification. .

(3) It is reminded that many people are not sensitive to the taste of organic tin reagents, or they do not smell it at all. Of course, there are friends who are very sensitive to tin reagents. For many friends who can't smell tin test agents, poisoning is unknowingly, so preventing poisoning is the key. [Organic tin has high or medium toxicity. It can enter the body through the respiratory tract, digestive tract, and skin mucosa to damage the liver and kidney and nervous system. Preventing poisoning is the key. After poisoning, wash and dispel it in time to actively treat primary and complications. Mild poisoning and skin irritation are not obvious. Severe poisoning may have obvious sequelae of the nervous system and kidney. .

(4) At present, there is no special effect on organic tin poisoning, and organic tin can accumulate in the body. The treatment period of mild poisoning is also relatively long, which can cause continuous damage to the human body.

2. Sirine phosphorus phosphorus

Colorless clarification liquid. There is irritating smell. Strong smoke. It is hygroscopic. Return to water and ethanol to decompose heat or even exploded. Relators (D25) 1.675. The melting point is 1.25 ° C. The boiling point is 105.8 ℃. Middle poison, half of death (rats, meridian) 380mg/kg. It is tearful and corrosive. It is forbidden to use compounds -strong rejuvenation, active metal, water and alcoholic compounds. [Heat is decomposed into H3PO4 and HCL, which has a stimulating corrosion effect on the skin and mucous membranes, and has tears; it is similar to toxicity and light; it is easy to burns to the skin, produce erythema and edema]. The reactions involved in POCL3 are prohibited from using a closed reaction container such as glass tube, stuffy can, and high -pressure kettle to react.

General operation:

(1) Operation with protective glasses, gloves, white coats, and ventilation cabinets.

(2) Adding the substrate to POCL3 is relatively stable, especially the active compound (such as the transposition chlorine of pyridine nitrogen oxidation compounds. If it is added, it is risk of explosion).

(3) There must be a tail gas absorption device during the reaction, which can be connected from the upper end of the condensate tube -buffer bottle -alkaline liquid tail gas absorption device. Do not connect to the middle of the three links and a pointed straw.

(4) POCL3 dosage:

A. A small amount of POCL3 can slowly pour the reaction liquid into the constant temperature water (the stability of the careful product, which may cause local hydrolysis products, especially the product of pyridin chlorine or its pyrine). Change, when the temperature rises, add ice cubes to cool down in time.

B. A large number of POCL3 can be concentrated as possible (it is recommended not to decompress and distille on the evaporation instrument, which can be condensed with decompression distillation). If it is steamed, the reactant becomes a strong solid, and it is difficult to transfer it. It can quench during slurry; or after steaming most of POCL3, add toluene to boil the remaining POCL3, and then quench; , DCM, THF, etc.) After dissolving.

(5) Do not use ice water when extracting POCL3 (it is relatively long in ice water, which is easy to store heat and causes sudden outbreak, which is very easy to rinse); If the alkali liquid is neutral, you must also pay attention to generating a large amount of CO2 caused by the punch; when POCL3 returns, you must remember to apply vacuum grease on the condensate tube to prevent the reaction bottle and the condensation tube sticking together and unable to pull it down; especially reminded by reminding Yes, if you remove POCL3 with a spin, do not drop the pot or pump pump to suck it up. You must watch it next to it. Save your reaction at this time.

(6) It is strictly forbidden to pour the recycled POCL3 directly into the waste liquid barrel without quenching.

(7) The product of the hybrids may have strong allergies to people, especially the skin, and pay attention to strict protection.

(8) PCL3 and PBR3 are similar to the response.

Many of the chemicals in the test work are toxic to the human body. They have different ways and degrees of poisoning of the human body. Some poisons may have several ways to enter the human body, and some poisonous poison is chronic and accumulated, so they must pay enough attention.

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