Environmental conditions for storing laboratory chemicals
Product Manager：Nick Wilde
During the storage of chemicals, they often clump or freeze due to fluctuations in temperature and humidity in the surrounding environment, leading to a decrease in quality and an increase in costs. Therefore, it is particularly important to take appropriate temperature and humidity control measures for proper storage based on the physical and chemical properties of different chemical reagents.
Some reagents have the characteristics of easy hygroscopicity, deliquescence or hydrolysis, while others are prone to react with oxygen, carbon dioxide or other gases in the air. In addition, some reagents may deteriorate under the influence of light or ambient temperature.
Differentiated management and preservation measures
Low-boiling-point compounds and medications requiring low-temperature storage must be strictly placed in a low-temperature refrigerator as per regulations;
All medications and prepared reagents that need to be protected from light must be encapsulated in brown containers (bottles) or wrapped and shielded using dark-colored paper;
All medications should be uniformly placed in a medication cabinet and strictly prohibited from being mixed with prepared solutions;
Liquid medications should be stored in low cabinets and separated from solid medications to avoid confusion;
Acids, bases, oxidants, reductants, and reagents that may react violently upon mixing must be strictly stored separately to prevent accidents caused by tipping over, breaking, etc.;
For medications stored at room temperature, moisture-proof measures are crucial to prevent solid medications from caking. It is worth noting that liquid samples such as glacial acetic acid may solidify at excessive temperatures but can resume their liquid state when placed in a warmer environment;
In northern cold regions, due to the fact that some laboratory air conditioners only have cooling functions, reagents with freezing points close to room temperature may solidify in winter and resume their liquid state in summer. Additionally, since reagent bottles are typically made of thick-walled ordinary glass, excessive temperature changes may cause them to crack. Therefore, for easily frozen corrosive substances such as glacial acetic acid and methanol prone to polymerization and precipitation, the warehouse temperature should be maintained at around 15°C, and warming measures should be taken in winter;
Although sulfuric acid and hydrochloric acid both belong to acids, sulfuric acid should be stored separately from formic acid, acetic acid, and hydrochloric acid;
Formic acid, acetic acid, and hydrochloric acid have strong volatility, so proper ventilation should be ensured during storage to promptly exhaust acid mist;
Due to its strong oxidizing and dehydrating properties, sulfuric acid should be isolated and stored separately to ensure safety.
Nine common chemical storage environmental conditions
Given the unique hazardous properties of various chemicals, their requirements for temperature and humidity control vary to ensure safe storage and quality maintenance.
I. Explosive Materials: The storage warehouse temperature must be maintained below 30°C, and simultaneously, the relative humidity should be regulated between 75% and 80% to ensure safety.
II. Oxidizing Agents: The temperature control for conventional oxidizing agents should be below 30°C. For oxidizing agents containing crystal water, such as nitrates, the storage temperature should be even lower, at below 28°C, to prevent deliquescence due to heat-induced melting. These materials should be stored in insulated warehouses with a relative humidity controlled below 75%.
III. Compressed and Liquefied Gases: The maximum temperature for storing such items in a warehouse is 32°C, and the relative humidity should not exceed 80% to prevent rusting of steel cylinders.
IV. Pyrophoric Materials: The warehouse temperature for these should range between 28°C and 30°C, with the relative humidity kept below 80%. Specifically, warehouses storing yellow phosphorus should not drop below 3°C in winter to avoid safety risks.
V. Moisture-Proof Materials: When storing such items, the warehouse temperature should be approximately 30°C, and the relative humidity should be strictly controlled below 75%, along with implementing specialized moisture-proof measures.
VI. Flammable Liquids: The temperature inside the warehouse must be closely monitored, particularly adjusting it based on the liquid's boiling point and flash point to ensure safety.
VII. Flammable Solids: Excessive humidity can affect their safe storage. For instance, nitrocellulose requires 30% ethanol as a wetting agent, and the warehouse temperature should be controlled below 30°C. The relative humidity for substances like camphor and refined tea should be maintained below 80%. The storage warehouse temperature for Class II flammable solids should not exceed 32°C.
VIII. Toxic Materials: The warehouse temperature should be controlled below 32°C, and the relative humidity should remain below 80%. Especially for cyanides, the warehouse should be kept dry to prevent them from reacting with moist air to produce toxic gases.
IX. Corrosive Materials: Due to the wide variety and differing properties of these materials, which include both solids and liquids, temperature and humidity control should be based on their specific characteristics. For example, corrosive materials that deteriorate or emit smoke upon absorbing moisture, such as phosphorus pentoxide and phosphorus trichloride, should be kept in dry warehouses with a relative humidity below 75%. For volatile bromine and easily decomposable hydrogen peroxide (with a concentration below 40%), the warehouse temperature should be maintained below 28°C, ideally around 25°C. For corrosive materials that can freeze or undergo polymerization and precipitation when exposed to cold, such as glacial acetic acid and methanol, the warehouse temperature should be maintained at around 15°C, with warming measures taken during winter.
Eight major precautions
I. Prevention of Volatilization
1. Oil Sealing Method: For volatile inorganic liquids such as ammonia solution, concentrated hydrochloric acid, and concentrated nitric acid, 10 to 20 drops of mineral oil (avoid using vegetable oil) can be dripped onto the liquid surface to slow down volatilization.
2. Water Sealing Method: Adding 5 milliliters of water to carbon disulfide can effectively extend its shelf life. For mercury, water can be added to cover it to prevent mercury vapor from being released into the air. Additionally, sulfur powder should be placed near the storage area of mercury. In case of mercury spillage, sulfur powder can be quickly sprinkled to eliminate it through chemical reaction.
3. Wax Sealing Method: For lightweight or soluble volatile liquids such as ether, ethanol, and formic acid, as well as volatile solids like naphthalene and iodine, the bottle should be tightly closed, and a layer of wax should be applied to the bottle neck. For bromine, besides wax sealing the original bottle, it should also be placed in a plastic cylinder filled with activated carbon, with the cylinder mouth also wax sealed.
II. Moisture Protection
1. Wax Sealing Protection: Substances like bleach and sodium peroxide, which can decompose or explode upon absorbing water, as well as substances prone to deliquescence like sodium hydroxide, should be wax sealed. Substances like ammonium nitrate and sodium sulfate, which can absorb water and form clumps, should also be tightly wax sealed to prevent bottle breakage.
2. Storage in Desiccators: Substances that are highly susceptible to moisture and deterioration, such as calcium carbide, anhydrous copper sulfate, phosphorus pentoxide, and silica gel, as well as substances prone to oxidation like red phosphorus, should be stored in desiccators.
3. Storage in Ground-Glass Stoppered Bottles: Concentrated sulfuric acid should be tightly sealed to prevent water absorption, but due to its frequent use, it is advisable to store it in a ground-glass stoppered bottle with the original stopper to avoid mixing.
4. Special Storage Environment: "Special chemicals" should be stored in a basement with quicklime, slaked lime, and double-layered tar paper to ensure they remain dry and secure.
III. Prevention of Deterioration
1. Antioxidation: Substances prone to oxidation, such as sodium sulfite, ferrous sulfate, and sodium thiosulfate, should have their bottle necks coated with wax to prevent oxidation.
2. Prevention of Carbonation: Substances that easily absorb carbon dioxide, such as sodium silicate, sodium peroxide, and caustic soda, should also be wax sealed.
3. Prevention of Efflorescence: Substances prone to efflorescence, such as crystalline sodium carbonate and crystalline copper sulfate, should be wax sealed and stored in a basement.
4. Prevention of Decomposition: Substances that decompose easily upon heating, such as ammonium bicarbonate and concentrated nitric acid, should be wax sealed and stored in a basement.
5. Storage with Activated Carbon: Activated carbon, which can adsorb various gases and deteriorate, should be stored in a desiccator.
6. Special Storage of Yellow Phosphorus: Yellow phosphorus, which can ignite spontaneously upon exposure to air, should always be stored in water, with regular checks on the water level.
7. Storage of Alkali Metals: Alkali metals such as potassium and sodium should be stored in kerosene to isolate them from air.
8. Preservation of Ferrous Sulfate Solution: To extend the shelf life of ferrous sulfate solution, a few drops of dilute sulfuric acid and an excess of fine iron powder can be added, and the solution should be wax sealed.
9. Preservation of Glucose Solution: Glucose solution is prone to mold growth, so a few drops of formaldehyde can be added for preservative treatment.
10. Preservation of Aldehydes: Formaldehyde is prone to polymerization, so a small amount of methanol should be added immediately after opening the bottle for stabilization. Ethanal should be mixed with ethanol to prevent polymerization.
IV. Light Protection
1. Storage in Brown Bottles: Silver nitrate, concentrated nitric acid, and most organic chemicals should be stored in brown bottles to prevent photolysis.
2. Storage in Basements: Substances like nitrates, which require both heat and light protection, should be stored in basements.
3. Painting with Black Paint: Organic reagent cabinets should be painted black to prevent light exposure.
4. 4. Curtain Coverage: Laboratories should use double-layered curtains made of inner red and outer black fabric to block light.
V. Prevention of Poisoning
1. Storage of Highly Toxic Materials: Highly toxic materials such as phosphorus, silver nitrate, potassium chlorate, and mercuric chloride should be stored in basements. A double-lock management system should be implemented, with records of usage maintained and regular inspections conducted.
2. Preservation of Phosphide Compounds: Materials like calcium phosphide and aluminum phosphide, which release highly toxic gases when exposed to moisture, should be kept in desiccators and labeled with red tags as warnings.
3. Adsorption of Gaseous Substances: In the absence of a fume hood, lime can be spread on the ground to adsorb certain poisonous gaseous substances.
4. Warning for Corrosive Substances: Corrosive substances such as concentrated acids, bases, bromine, and phenol should be labeled with red tags for warning purposes.
VI. Earthquake Prevention
1. Storage of Explosive Materials: Substances like ammonium nitrate, which are prone to explosion when subjected to vibrations, should be stored in basements to prevent hazards caused by vibrations.
2. Protection of Large Crystals: Fragile substances such as homemade large crystals of alum and copper sulfate should be wrapped in soft paper and placed in wide-mouthed reagent bottles, with additional cushioning provided.
VII. Fire Prevention
1. Setup of Fire-fighting Equipment: Fire-fighting equipment such as water tanks, fire buckets, sand tanks, and foam extinguishers should be placed in prominent and accessible locations within the instrument room, with regular inspections and updates conducted.
2. Modification of Electrical Wiring: Indoor electrical wiring should be concealed to prevent short circuits caused by drug fumigation, which could lead to fires.
VIII. Rodent Control
1. Paste Preparation: A higher concentration of phenol can be added to paste to repel mice.
2. Utilization of Volatile Drugs: Volatile drugs such as formaldehyde and coal tar soap can be placed in indicator cabinets to repel mice. For cabinets with severe mouse infestations, concentrated hydrochloric acid and concentrated ammonia can be alternately stored to create an unfavorable environment for mice.
3. Use of Lead Acetate: Paste made with lead acetate can be applied to the walls of mouse holes. When mice come into contact with it and lick it off, they will ingest the poison and die (lead acetate tastes sweet but is highly toxic).
Medicine Storage and Container Selection
1. Container Selection Guidelines:
Solid substances should be stored in wide-mouthed bottles.
Liquids are better suited for narrow-mouthed bottles to prevent evaporation.
Substances that decompose easily upon exposure to light, such as nitric acid, silver nitrate, and chlorine water, should be stored in brown bottles to protect them from light.
2. Stopper Material Selection:
Alkaline solutions, such as NaOH and Na2CO3, should avoid using glass stoppers and instead use rubber stoppers to prevent corrosion.
Strongly oxidizing solutions (e.g., nitric acid, potassium permanganate) and organic solvents (e.g., gasoline, benzene) should not use rubber stoppers but instead glass stoppers to avoid swelling or dissolution.
3. Liquid Seal Preservation:
Sodium should be immersed in kerosene to isolate it from air.
White phosphorus requires water sealing to prevent spontaneous combustion.
Liquid bromine also needs to be preserved with water sealing, and carbon tetrachloride may also use water sealing in some cases.
4. Air-Sensitive Substances Sealing Preservation Strategies:
Substances that react with water or absorb water, such as CaCl2 and alkaline lime, require strict sealing.
Substances that react with CO2, such as NaOH, Ca(OH)2, and Na2O2, also need to be isolated from air.
Substances that react with O2, such as FeSO4, Na2SO3, C6H5OH, and Na2S, also require sealed storage measures.
5. Special Substance Preservation Schemes:
HF, due to its reactivity with glass, should be stored in plastic bottles.
Strong bases and certain alkaline aqueous solutions may corrode glass stoppers, so rubber stoppers are recommended (e.g., NaOH, KOH solutions).
Concentrated HNO3, concentrated H2SO4, and liquid bromine, due to their strong oxidizing or corrosive properties, should not use rubber stoppers.
Light-sensitive reagents, such as HNO3, AgNO3, and chlorine water, should be stored in brown bottles and kept in a cool place.
Liquid bromine should be sealed and stored in a brown bottle with a glass stopper, and a small amount of water should be added for water sealing.
Hydrofluoric acid, due to its reactivity with glass, should be stored in plastic bottles with plastic lids.
Ammonia water, concentrated hydrochloric acid, iodine, naphthalene, and low-boiling-point organics should also be sealed with plastic lids and kept in a cool place.
Reference Table:
Aladdin：https://www.aladdinsci.com