Organic matter is hydrocarbons (hydrocarbons) and their derivatives, referred to as organic matter. Except water and some inorganic salts, almost all components of organisms are organic substances, such as starch, sucrose, oil, protein, nucleic acids and various pigments. In the past, it was mistakenly thought that only animals and plants (organisms) could produce organic matter, so it was named "organic". Nowadays, many natural products can not only be synthesized artificially, but also be separated from animals and plants, coal, oil and natural gas. And made into various necessities for industrial and agricultural production and people's life, such as plastics, synthetic fibers, pesticides, artificial rubber, etc. Compared with inorganic substances, there are many kinds of organic substances, which are generally more volatile, lower in melting point and boiling point, and slower (more complicated) in reaction. Soluble in organic solvents, flammable. Carbon atoms can be connected with each other through valence bonds to form a variety of structures, forming a large number of different kinds of organic molecular skeletons. According to the basic structure, organic compounds can be divided into three categories: (1) open-chain compounds, also known as aliphatic compounds, because they originally existed in oils and fats. Its structural feature is that carbon and carbon are connected to form an open chain. (2) Carbocyclic compounds (containing rings composed entirely of carbon atoms) can be divided into two categories: alicyclic compounds (which can be regarded as closed-loop compounds in structure) and aromatic compounds (containing benzene rings). (3) Heterocyclic compounds (rings containing carbon atoms and other elements). In hydrocarbon molecules, the carbon atom with valence of * * * is the skeleton, and other bonds of carbon are combined with hydrogen. The skeleton of hydrocarbons is very stable because the carbon atoms forming carbon-carbon single bonds and double bonds share the electron pairs between them equally. Hydrogen atoms of hydrocarbons can be replaced by different functional groups (functional groups) to produce different kinds of organic substances. Functional groups determine the main properties of molecules, so organic substances are often classified according to their functional groups. The functional groups of organic biomolecules are chemically more active than their hydrocarbon skeletons. They can change the geometry of adjacent atoms and the distribution of electrons on them, thus changing the chemical reactivity of the whole organic molecule. From the functional groups in organic molecules, we can analyze and infer their chemical behaviors and reactions. For example, enzymes (catalysts for cells) can recognize special functional groups in biomolecules and catalyze their structural changes. Most biomolecules are multifunctional and contain two or more functional groups. In these molecules, each functional group has its own chemical characteristics and reactions. For example, amino acids have at least two functional groups-amino and carboxyl. The chemical properties of alanine are basically determined by its amino and carboxyl groups. For example, glucose is also a multifunctional biomolecule, and its chemical properties are basically determined by two functional groups: hydroxyl group and aldehyde group. Functional groups of biomolecules play an important role in biological activity. The following table lists some other functional groups in biomolecules.
Such as methane
The molecular formula of methane is CH4. The simplest organic compound. Methane is a colorless and odorless gas with a boiling point of-16 1.4℃, which is lighter than air. It is a flammable gas, which is extremely difficult to dissolve in water. A mixture of methane and air in a proper proportion will explode when it meets sparks. Chemical properties are quite stable, and generally do not react with strong acid, alkali or strong oxidant (such as KMnO4). Under proper conditions, oxidation, pyrolysis and halogenation will occur.
Methane is widely distributed in nature and is one of the main components of natural gas, biogas, biogas and coal gas. It can be used as fuel and raw material for producing hydrogen, carbon monoxide, carbon black, acetylene, hydrocyanic acid and formaldehyde.
4 13kJ/mol, 109 28', the methane molecule is a regular tetrahedron space configuration, and the above structural formula only explains the connection of atoms in the molecule, but can't really explain the spatial relative position of atoms.
1. Physical and chemical constants of substances:
GBNo。 2 1007
Si Nuo. 74-82-8
Chinese name methane
English name methane; ; marsh gas
marsh gas
Appearance and properties of colorless and odorless gas with molecular formula CH4.
Molecular weight 16.04 vapor pressure 53.32kPa/- 168.8℃ flash point:-188℃
Melting point-182.5℃ boiling point:-16 1.5℃ slightly soluble in water, soluble in alcohol and ether.
Density Relative density (water =1) 0.42 (-164℃); The relative density (air = 1)0.55 is relatively stable.
Danger sign 4 (flammable liquid) is mainly used as fuel and manufacturing carbon black, hydrogen, acetylene, formaldehyde, etc.
2. Impact on the environment:
I. Health hazards
Invasion route: inhalation.
Health hazard: Methane is basically nontoxic to people, but when the concentration is too high, the oxygen content in the air is obviously reduced, which makes people suffocate. When the methane in the air reaches 25%-30%, it can cause headache, dizziness, fatigue, inattention, rapid breathing and heartbeat, and ataxia. If you don't leave in time, you may suffocate. Skin contact with liquefied products can cause frostbite.
Second, toxicological data and environmental behavior.
Toxicity: It belongs to slight toxicity. Allow gas to safely diffuse into the atmosphere or be used as fuel. There are simple asphyxia and high concentration hypoxia asphyxia leading to poisoning. When the air reaches 25 ~ 30%, dizziness, accelerated breathing and dyskinesia occur.
Acute toxicity: mice inhaled 42% concentration for 60 minutes, which had anesthetic effect; Rabbits inhaled 42% concentration for 60 minutes, which had anesthetic effect.
Hazard characteristics: flammable, can form explosive mixture when mixed with air, and is in danger of burning and explosion when exposed to heat source and open flame. It reacts violently with strong oxidants such as dibromo pentoxide, chlorine gas, hypochlorous acid, nitrogen trifluoride, liquid oxygen and oxygen difluoride.
Combustion (decomposition) products: carbon monoxide and carbon dioxide.
3. The field emergency monitoring method:
4. Laboratory monitoring methods:
Determination of Harmful Substances in the Air by Gas Chromatography (2nd Edition), edited by Hang Shiping.
Combustible solvent colorimetry; Standard Test Method for Volumetric Analysis of Water and Wastewater 20th Edition (USA)
5. Environmental standards:
The maximum allowable concentration of harmful substances in the air of workshops in the former Soviet Union is 300mg/m3.
American Health Standard for Asphyxiating Gases in Workplace
6. Emergency treatment and disposal methods:
First, the emergency treatment of leakage
Quickly evacuate people in the leaked and polluted area to the windward, isolate them, and strictly restrict access. Cut off the fire. It is recommended that emergency personnel wear self-contained positive pressure breathing apparatus and fire protection clothing. Cut off the leakage source as much as possible. Reasonable ventilation and accelerated diffusion. Spray water is diluted and dissolved. Build a dike or dig a pit to contain a large amount of wastewater. If possible, use an exhaust fan to send the leaked gas to an open place, or install a suitable nozzle for combustion. You can also move the leaking container to an open place and pay attention to ventilation. Leaked containers should be properly treated, repaired and inspected before use.
Second, the protective measures
Respiratory system protection: generally no special protection is needed, but it is recommended to wear a self-priming filter gas mask (half mask) under special circumstances.
Eye protection: Generally, special protection is not needed, and safety glasses can be worn when exposed to high concentration.
Physical protection: wear anti-static work clothes.
Hand protection: wear gloves for general operation.
Others: Smoking is strictly prohibited in the workplace. Avoid long-term repeated contact. Work in storage tanks, confined spaces or other high concentration areas must be supervised.
Third, first aid measures.
Skin contact: If frostbite occurs, seek medical attention.
Inhalation: leave the scene quickly and go to a place with fresh air. Keep the respiratory tract unobstructed. If you have difficulty breathing, give oxygen. If breathing stops, give artificial respiration immediately. See a doctor.
Fire extinguishing method: cut off the gas source. If the gas source cannot be cut off immediately, it is not allowed to extinguish the burning gas. Spray water to cool the container, and if possible, move the container from the fire to an open place. Extinguishing agent: atomized water, foam, carbon dioxide and dry powder.
Part I: Names of Chemicals
Chinese name of chemical: methane
English name of chemical: methane
English Name 2: Biogas
English name 2: Marsh gas
Technical specification code: 5 1
Si Nuo. :74-82-8
Molecular formula: CH4
Molecular weight: 16.04
Part II: Composition/Composition Information
Content of harmful substances.
Methane 74-82-8
The third part: risk overview.
Hazard category:
Invasion route:
Health hazard: Methane is basically nontoxic to people, but when the concentration is too high, the oxygen content in the air is obviously reduced, which makes people suffocate. When the methane in the air reaches 25% ~ 30%, it can cause headache, dizziness, fatigue, inattention, accelerated breathing and heartbeat, and ataxia. If you don't leave in time, you may suffocate. Skin contact with liquefied products can cause frostbite.
Environmental hazards:
Danger of explosion: This product is flammable and suffocating.
Part IV: First aid measures
Skin contact: If frostbite occurs, seek medical attention.
Eye contact:
Inhalation: leave the scene quickly and go to a place with fresh air. Keep the respiratory tract unobstructed. If you have difficulty breathing, give oxygen. If breathing stops, give artificial respiration immediately. See a doctor.
Intake:
Part V: Fire Prevention Measures
Hazard characteristics: flammable, can form explosive mixture when mixed with air, and is in danger of burning and explosion when exposed to heat source and open flame. It reacts violently with strong oxidants such as dibromo pentoxide, chlorine gas, hypochlorous acid, nitrogen trifluoride, liquid oxygen and oxygen difluoride.
Harmful combustion products: carbon monoxide and carbon dioxide.
Fire extinguishing method: cut off the gas source. If the gas source cannot be cut off, it is not allowed to extinguish the flame at the leak. Spray water to cool the container, and if possible, move the container from the fire to an open place. Extinguishing agent: atomized water, foam, carbon dioxide and dry powder.
Part VI: Emergency treatment of leakage.
Emergency treatment: quickly evacuate the personnel from the leaked and polluted area to the upwind area, isolate them and strictly restrict access. Cut off the fire. It is recommended that emergency personnel wear self-contained positive pressure breathing apparatus and anti-static work clothes. Cut off the leakage source as much as possible. Reasonable ventilation and accelerated diffusion. Spray water is diluted and dissolved. Build a dike or dig a pit to contain a large amount of wastewater. If possible, use an exhaust fan to send the leaked gas to an open place, or install a suitable nozzle for combustion. You can also move the leaking container to an open place and pay attention to ventilation. Leaked containers should be properly treated, repaired and inspected before use.
Part VII: Operation, Disposal and Storage
Precautions for operation: closed operation and comprehensive ventilation. Operators must be specially trained and strictly abide by the operating procedures. Stay away from kindling and heat sources, and smoking is strictly prohibited in the workplace. Use explosion-proof ventilation system and equipment. Prevent the gas in the workplace from leaking into the air. Avoid contact with oxidants. During transmission, gas cylinders and containers must be grounded and bridged to prevent static electricity. Lightly load and unload when handling, so as to prevent the cylinders and accessories from being damaged. Equipped with corresponding varieties and quantities of fire fighting equipment and leakage emergency treatment equipment.
Precautions for storage: Store in a cool and ventilated warehouse. Stay away from fire and heat sources. The reservoir temperature should not exceed 30℃. Should be stored separately from oxidant, etc. , and should not be mixed. Adopt explosion-proof lighting and ventilation facilities. It is forbidden to use mechanical equipment and tools that are easy to generate sparks. The storage area should be equipped with emergency treatment equipment for leakage.
Part VIII: Contact Control/Personal Protection
occupational exposure limits
China MAC(mg/m3): No standard has been established.
Maximum allowable concentration in former Soviet Union (mg/m3): 300.
ACGIH asphyxiating gas
TLVWN: No standard has been established.
Monitoring method:
Engineering control: the production process is closed and fully ventilated.
Respiratory system protection: generally no special protection is needed, but it is recommended to wear a self-priming filter gas mask (half mask) under special circumstances.
Eye protection: Generally, special protection is not needed, and safety glasses can be worn when exposed to high concentration.
Physical protection: wear anti-static work clothes.
Hand protection: wear gloves for general operation.
Other protection: Smoking is strictly prohibited in the workplace. Avoid long-term repeated contact. Work in storage tanks, confined spaces or other high concentration areas must be supervised.
Part IX: Physical and Chemical Characteristics
Main ingredients: pure products
Colorless and odorless gas.
PH value:
Melting point (℃):- 182.5
Boiling point (℃):- 16 1.5
Relative density (water = 1): 0.42 (- 164℃)
Relative steam density (air = 1): 0.55.
Saturated vapor pressure (kpa): 53.32 (- 168.8℃)
Combustion heat (kJ/mol): 889.5
Critical temperature (℃):-82.6
Critical pressure (MPa): 4.59
Logarithmic value of octanol/water partition coefficient: No data available.
Flash point (℃):- 188
Ignition temperature (℃): 538
Upper explosion limit% (v/v): 15
Lower explosive limit% (volume/volume): 5.3
Solubility: slightly soluble in water, soluble in alcohol and ether.
Main uses: used as fuel and manufacturing carbon black, hydrogen, acetylene, formaldehyde, etc.
Other physical and chemical properties:
Part X: Stability and Reactivity
Stability:
Prohibited compounds: strong oxidants, fluorine and chlorine.
Conditions for avoiding contact:
Aggregation danger:
Decomposition products:
Part XI: Toxicological data
Acute toxicity: LD50: No data available.
LC50: No data.
Subacute and chronic toxicity:
Irritant:
Sensitization:
Mutagenicity:
Teratogenicity:
Carcinogenicity:
Part XII: Ecological data
Eco-toxicological toxicity:
Biodegradability:
Non-biodegradable:
Bioaccumulation or bioaccumulation:
Other harmful effects: the substance may be harmful to the environment, and special attention should be paid to fish and water. Special attention should also be paid to the pollution of surface water, soil, atmosphere and drinking water.
Part XIII: Abandonment and Disposal
Nature of waste:
Disposal method of waste: refer to relevant national and local laws and regulations before disposal. Incineration is recommended.
Abandoned preventive measures:
Part XIV: Transportation Information
Dangerous goods number: 2 1007
Un number: 197 1
Packaging mark:
Packing category: O52
Packing: steel cylinder.
Precautions for transportation: the safety helmet on the cylinder must be worn when transporting the cylinder. Cylinders are generally flat, and the bottle mouths should be in the same direction and cannot cross; The height shall not exceed the vehicle guardrail, and it shall be fastened with triangular wooden mats to prevent rolling. Transport vehicles should be equipped with corresponding varieties and quantities of fire fighting equipment during transportation. The exhaust pipe of the vehicle carrying this article must be equipped with a fire retardant device, and it is forbidden to use mechanical equipment and tools that are easy to generate sparks for loading and unloading. It is forbidden to transport with oxidant. It should be transported in the morning and evening in summer to prevent sun exposure. Stay away from fire and heat sources during stopovers. Highway transportation shall follow the prescribed route and shall not stay in residential areas and densely populated areas. When transporting by rail, it is forbidden to slip.
Part XV: Regulatory Information
Regulatory information: Regulations on the Safety Management of Hazardous Chemicals (promulgated by the State Council 1987 in February), Detailed Rules for the Implementation of the Regulations on the Safety Management of Hazardous Chemicals (Hua Laofa [1992] No.677) and Regulations on the Safe Use of Chemicals in the Workplace (issued by the Ministry of Labor [1996] 427). Classification and Labeling of Commonly Used Hazardous Chemicals (GB 13690-92) classifies this substance as Class 2. 1 combustible gas.