月: 2023年1月

What Is Phosphorus?

Phosphorus is an allotrope of phosphorus, appearing as a reddish-brown powder of equiaxed crystals.

Alongside phosphorus, there are white, purple, and black allotropes. All, except white phosphorus, are highly stable and less toxic. White phosphorus is highly toxic and ignites in the air. As phosphorus derives from white phosphorus, caution is advised due to potential white phosphorus content.

White phosphorus is often called yellow phosphorus due to its changing property to red phosphorus. The presence of impurities like red phosphorus turns it yellow. White phosphorus is also registered as yellow phosphorus under various laws and regulations.

Uses of Phosphorus

Phosphorus is utilized as a raw material in fireworks, matches, and more. Its applications include:

1. Flame Retardant

Despite being highly flammable, phosphorus becomes less so when mixed with flammable resin. In a fire, the red phosphorus in the resin reacts with air to form a fire-extinguishing phosphoric acid condensate.

2. Fertilizer Raw Material

Phosphorus serves as a critical ingredient in fertilizers, providing essential phosphoric acid through ammonium phosphate.

3. Others

In the semiconductor industry, high-purity phosphorus is used as a dopant and in organic synthesis, among other applications.

Properties of Phosphorus

Phosphorus, with a molecular formula of P₄ and weight of 123.9, sublimates at 400°C and boils at 590°C under high pressure. It’s insoluble in water and several organic solvents.

The specific gravity of phosphorus varies by allotrope: 1.82 (white), 2.36 (purple), and 2.69 (black).

Phosphorus is stable, not igniting in air unlike white phosphorus, which does. However, it’s sensitive to oxidizing agents and friction, and can ignite or explode under certain conditions.

High molecular weight phosphorus is produced by polymerizing white phosphorus under high-temperature, air-deprived conditions.

Other Information on Phosphorus

How Phosphorus Is Produced

Phosphorus is produced from ore through white phosphorus. The process involves:

1. White Phosphorus Production
Mixing phosphorus ore, coke, and silica, then heating in an electric furnace to produce phosphorus vapor, which is condensed and recovered.

2. Production of Phosphorus
Yellow phosphorus is converted to phosphorus by heating in a reaction tank. The resultant phosphorus is then processed to remove unreacted material and obtain phosphorus powder.

What Is Sodium Bisulfate?

Sodium bisulfate, also known as sodium hydrogen sulfate, is a white crystalline salt composed of sodium and hydrogen sulfate.

Its chemical formula is NaHSO₄, with a molecular weight of 120.06, and its CAS number is 7681-38-1. Another term for sodium bisulfate is sulfuric acid, monosodium salt.

Uses of Sodium Bisulfate

Sodium bisulfate serves primarily as a fluxing agent in the analysis of minerals and poorly soluble salts, and for cleaning platinum equipment. Its efficacy stems from the ability of hydrogen sulfate to transform into a soluble sulfate upon melting with insoluble salts, a process known as hydrogen sulfate melting.

Additionally, sodium bisulfate functions as a food additive, enhancing pancake mixes, beverages, dressings, sauces, and meat processing, and preventing browning in fresh-cut produce. It offers a preferred alternative to citric, malic, or phosphoric acid for reducing pH without increasing acidity, also serving as an anti-browning agent.

Its other uses include metal surface treatment, bitumen treatment agents, water disinfectants, pH adjusters, and applications in the soap, brick, cement, and papermaking industries.

Properties of Sodium Bisulfate

Sodium bisulfate, lacking a boiling or melting point, decomposes into Na₂S₂O₇ at approximately 315°C. With a density of 2.74 g/cm³, it is a stable, hygroscopic acid salt, highly soluble in water at 50 g/100 mL, yielding strongly acidic solutions.

Though highly toxic to some echinoderms, it is nearly harmless to many other organisms, making it a strategic choice for managing crown-of-thorns starfish outbreaks.

Other Information on Sodium Bisulfate

1. Manufacturing Process of Sodium Bisulfate

Anhydrous sodium bisulfate is produced by reacting concentrated sulfuric acid with sodium chloride and applying heat until melting occurs.

NaOH + H₂SO₄ → NaHSO₄ + H₂O

The monohydrate form results from the reaction of concentrated sulfuric acid with an aqueous solution of sodium sulfate.

Na₂SO₄ + 2H₂O + H₂SO₄ → 2NaHSO₄·H₂O

Sodium bisulfate is industrially synthesized as an intermediate in the Mannheim process, through the reaction of sodium chloride with sulfuric acid.

NaCl + H₂SO₄ → HCl + NaHSO₄

2. Reaction of Sodium Bisulfate

Above 300°C, sodium bisulfate dehydrates, forming sodium pyrosulfate, which further decomposes into sodium sulfate and releases SO₃ upon heating.

2NaHSO₄ → Na₂S₂O₇ + H₂O
Na₂S₂O₇ → Na₂SO₄ + SO₃

3. Regulatory Information

While sodium bisulfate is not covered by major safety regulations, it is classified as a corrosive substance, necessitating careful handling.

4. Handling and Storage Precautions

Recommended handling and storage precautions include:

• Storing in a tightly sealed container, in a cool, dark place away from direct sunlight.
• Using glass or plastic containers to prevent reaction with metals.
• Operating only in outdoor or well-ventilated areas.
• Exercising caution when heated due to the release of toxic fumes.
• Avoiding unnecessary mixing with alcohol or water to prevent reactions.
• Being cautious of its reaction with many metals, which can generate flammable and explosive hydrogen gas.
• Wearing protective gloves, eyewear, and clothing during use.
• Washing hands thoroughly after handling.
• Washing with soap and water in case of skin contact, and rinsing eyes cautiously with water for several minutes in case of eye contact.

What Is Dimethyl Sulfate?

Dimethyl Sulfate is the dimethyl ester of sulfuric acid.

Other names include Dimethyl Sulfate, Methyl Sulfate, Dimethyl Sulfate Ester, and DMS. Dimethyl Sulfate is strictly a conventional name.

It is classified as a priority chemical substance under the Law Concerning the Evaluation of Chemical Substances and Regulation of Their Manufacture, etc. (Chemical Substances Control Law). It is also regulated under the Industrial Safety and Health Law, Poisonous and Deleterious Substances Control Law, and Fire Service Law, in addition to being a regulated item under the Water Pollution Control Law’s Accidental Measures (Designated Substances).

Uses of Dimethyl Sulfate

Dimethyl Sulfate is widely used as a strong alkylating agent. As a result, it is often used as a pharmaceutical or synthetic raw material. Specifically, it is often used to methylate the hydroxy group (-OH) of phenols and alcohols, the amino group (-NH₂) of amines, and the thiol group (-SH) of thiols.

It is also a well-known alkylating agent used in the chemical methylation of nucleic acids. Historically, it was used for DNA sequencing by the Maxam-Gilbert sequencing method.

Properties of Dimethyl Sulfate

Dimethyl Sulfate has a melting point of -32°C and decomposes at 188°C. It is a colorless oily liquid with a weak onion-like odor. It is soluble in ethanol, acetone, dichloromethane, and various ethers. It is insoluble in water and is gradually hydrolyzed.

Dimethyl Sulfate is not irritating, but is extremely toxic to the human body. If the vapor is inhaled or left on the skin, it can be absorbed into the body and cause poisoning. Kidneys, liver, and heart may be affected, and death may result from necrosis of the skin and inflammation of the respiratory mucous membranes, so care must be taken when handling it.

Structure of Dimethyl Sulfate

Dimethyl Sulfate is a neutral ester with the chemical formula (CH₃)₂SO₄ or (CH₃O)₂SO₂. It is also denoted as Me₂SO₄. Its molar mass is 126.13 g/mol and density is 1.33 g/ml.

Other Information on Dimethyl Sulfate

1. Synthesis of Dimethyl Sulfate

Reaction of fuming sulfuric acid with dry methanol or dimethyl ether yields methyl hydrogen sulfate. Methyl hydrogen sulfate can be distilled and converted to Dimethyl Sulfate.

Methyl hydrogen sulfate can also be synthesized by reacting methyl chlorosulfonate with methyl nitrite.

In industrial use, it is synthesized by the sequential reaction of dimethyl ether with sulfur trioxide (SO₃).

2. Reaction of Dimethyl Sulfate

Dimethyl Sulfate is generally used in the methylation of phenols and is also suitable for the methylation of alcohols. For example, tert-butyl methyl ether can be synthesized from tert-butanol. In the case of alkoxides, methylation is immediate. As with alcohols, methylation of thiols also occurs readily. Thioesters can be produced from thiocarboxylic acids.

Methylation of amines allows the synthesis of tertiary amines and quaternary ammonium salts. Quaternary ammonium compounds with long-chain alkyl groups can be used in clothing softeners and surfactants.

Dimethyl Sulfate can also cleave DNA base-specifically through the ring-opening reaction of the imidazole ring of guanine, which is useful in DNA strand breaks and sequencing. When reacted with copper(I) oxide, copper(I) sulfate is obtained.

3. Hazards of Dimethyl Sulfate

Cancer has been observed in rats after inhalation or intravenous administration. Because it is toxic and difficult to handle, it tends to be substituted for other methylating agents in the laboratory.

Methyl iodide is used for O-methylation and is expensive but less hazardous. Dimethyl carbonate is less toxic than methyl iodide and dimethyl sulfate and can be used in place of dimethyl sulfate for N-methylation. However, Dimethyl Sulfate may be judged an appropriate reagent because of its higher reaction efficiency and easier availability.

What Is Calcium Sulfate?

Calcium sulfate, known for its primary role in gypsum, is an inorganic compound with the formula CaSO₄. Appearing as a colorless to white crystal, it’s insoluble in water and found naturally in both dihydrate and anhydrate forms. Governed by various laws for chemical substance control, agricultural chemical control, and food sanitation, it is recognized for its utility and safety.

Uses of Calcium Sulfate

Its applications are diverse, ranging from food production, where it acts as a coagulant and additive, to agriculture as a calcium and sulfur fertilizer. In construction and medicine, it’s valued for its hardening properties, serving in ceramics, dental models, and casts for broken bones. Gypsum board, a recyclable material, is widely used in buildings for its excellent properties.

Properties of Calcium Sulfate

With a molecular weight of 136.14, a melting point of 1450°C, and solubility in concentrated sulfuric acid, calcium sulfate stands out for its chemical stability and versatility. It’s compatible with sodium thiosulfate and ammonium salts, forming complexes that extend its utility.

Types of Calcium Sulfate

Varied by water content, calcium sulfate presents as anhydrite or hard plaster in anhydrous form, hemihydrate with distinct structural types suitable for different applications, and dihydrate or soft plaster, often referred to as ordinary gypsum.

Other Information on Calcium Sulfate

How Calcium Sulfate is Produced

Calcium sulfate can be mined from natural ores or chemically synthesized. Chemically, calcium sulfate is obtained by the reaction of sulfuric acid and calcium content.

Calcium sulfate is also obtained in the wet phosphoric acid production process. Specifically, phosphate (Ca₅(PO₄)₃・F) reacts with phosphoric acid (H3PO4) to yield water-soluble monocalcium phosphate (Ca(H₂PO₄)₂) and hydrogen fluoride (HF). Sulfuric acid (H₂SO₄) is then added to produce phosphoric acid and calcium sulfate. The calcium phosphate obtained in this production process is also called gypsum phosphate. In addition to the phosphoric acid production process, calcium sulfate is also obtained as a byproduct of the flue gas desulfurization process and the titanium and hydrofluoric acid production processes.

What Is Ammonium Sulfide?

Ammonium sulfide, an ammonium salt of hydrogen sulfide, commonly appears as an aqueous solution and is also referred to as diammonium sulfide or ammonium monosulfide. It is produced by reacting urea nitrate with nitric acid and is known for its CAS number 124-47-0. While explosive under heat and shock, it generally remains safe under standard conditions.

Uses of Ammonium Sulfide

Used widely as an explosive sensitizer, explosive, desulfurizer, and organic reagent, ammonium sulfide’s primary application is in the production of improvised explosive devices (IEDs) due to the ease of synthesis from commonly available fertilizer industry chemicals. Despite its nitrogen content suggesting potential as a fertilizer, its acidity has limited this application. Additionally, it serves as an organic reagent in various chemical reactions.

Properties of Ammonium Sulfide

This compound, appearing as a white crystalline powder, decomposes at 152°C, releasing urea in aqueous solution and exhibiting acidity. It is soluble in hot water but insoluble in nitric acid, ether, chloroform, and benzene. Not inherently hygroscopic, its hygroscopicity increases when mixed with certain inorganic salts.

Types of Ammonium Sulfide

Marketed mainly for research and development as a wetted reagent to mitigate explosive risks, ammonium sulfide is available in laboratory-friendly quantities.

Other Information on Ammonium Sulfide

1. Chemical Reaction of Ammonium Sulfide

Highly reactive, ammonium sulfide can violently burn or explode upon heating or impact. It produces hazardous decomposition products and should be kept away from ignition sources.

2. Hazardousness of Ammonium Sulfide

Recognized as a hazardous substance, ammonium sulfide requires careful handling and personal protective equipment to mitigate risks of explosion, skin irritation, eye damage, and airway irritation.

3. Regulatory Information for Ammonium Sulfide

Ammonium sulfide’s explosive nature subjects it to strict regulatory controls under various safety laws, emphasizing the need for caution in its transport and handling.

What Is Potassium Bicarbonate?

Potassium bicarbonate is an inorganic compound known by its formula KHCO₃, with a molecular weight of 100.12 g/mol. Assigned CAS number 298-14-6, it is produced through the reaction of carbon dioxide with a potassium bicarbonate solution.

This substance forms as white monoclinic crystals that are odorless, dissolving in water to create a slightly alkaline solution, but it remains insoluble in ethanol and glycerin.

Uses of Potassium Bicarbonate

Potassium bicarbonate serves various purposes, including as a biochemical reagent, analytical reagent, buffer, organic synthesis material, pharmaceutical, and food additive. It is instrumental in producing pure potassium carbonate, deacidifying wine, and acting as a fungicide against several plant diseases. In wine production, it mitigates excess tartaric acid, enhancing quality by precipitating insoluble potassium hydrogen tartrate.

Properties of Potassium Bicarbonate

While nonflammable and thus not a direct fire risk, potassium bicarbonate can release carbon monoxide and carbon dioxide gases upon strong thermal decomposition. Due to its hygroscopic nature, recommended storage is in a dry environment.

Other Information on Potassium Bicarbonate

1. Regulatory Information on Potassium Bicarbonate

• Covered under various regulatory frameworks, indicating its wide application and environmental consideration.

2. Precautions for Handling and Storing Potassium Bicarbonate

• Guidelines include avoiding acidic substances to prevent carbon dioxide generation and storing them in appropriate conditions and containers to maintain their stability and effectiveness.

What Is Ammonium Bicarbonate?

Ammonium bicarbonate, an ammonium salt of carbonic acid, is represented by NH₄HCO₃ with a molecular weight of 79.06 g/mol. Assigned CAS number 1066-33-7, it is produced through the reaction of aqueous ammonia with carbon dioxide.

At standard conditions, it appears as a colorless or white crystalline powder. Decomposition releases a noticeable ammonia smell. Soluble in water, ammonium bicarbonate forms a slightly alkaline solution, but it does not dissolve in organic solvents like ethanol and acetone.

Uses of Ammonium Bicarbonate

Traditionally used as a baking powder, ammonium bicarbonate imparts a crispy texture to baked goods, making it preferred for commercial confectionery. It also serves as a pH adjuster in hair coloring treatments, enhancing dye absorption by altering hair cuticle dynamics. Beyond these applications, it is utilized in food processing, pharmaceuticals, cough syrups, antacids, and various industrial processes including fertilizer, dye, and plastic production.

Properties of Ammonium Bicarbonate

Heating ammonium bicarbonate leads to the production of ammonia, carbon dioxide, and water. It reacts with strong bases and acids, generating ammonia gas and carbon dioxide gas, respectively. It also interacts with aldehyde-containing substances, potentially causing coloration. Inhalation or contact can irritate, underscoring the need for cautious handling.

Other Information on Ammonium Bicarbonate

1. Regulatory Information on Ammonium Bicarbonate

• It is recognized under various regulatory frameworks, highlighting its environmental impact and safety considerations.

2. Handling and Storage Precautions

• Recommendations for safe storage include using appropriate containers and avoiding exposure to strong acids, moisture, and high temperatures to prevent decomposition and potential fire hazards.

What Is Lithium Carbonate?

Lithium carbonate, an inorganic compound denoted by Li₂CO₃, is derived from ores and brine. It serves as a precursor for various lithium-based products.

Uses of Lithium Carbonate

Utilized across numerous fields, lithium carbonate is crucial for producing glazes, glass, ceramics, battery materials, and pharmaceuticals. In lithium-ion batteries, it forms the basis for cathode active materials and electrolytes, essential for modern electronic devices and electric vehicles.

As a psychiatric medication, it’s effective in treating conditions like bipolar disorder due to its neurochemical impact. Additionally, its usage extends to manufacturing heat-resistant glassware and fast-bonding cement for tiles.

Properties of Lithium Carbonate

This compound appears as a colorless to white crystal solid, characterized by a molecular weight of 73.89, a density of 2.11 g/cm³, and a high melting point of 723°C. Lithium carbonate exhibits unique solubility properties, being relatively insoluble in water, with solubility decreasing as temperature increases. However, its solubility can increase significantly under pressure due to the formation of lithium bicarbonate.

Other Information on Lithium Carbonate

How Lithium Carbonate Is Produced

Lithium carbonate’s production involves extracting lithium from salt lake brines or minerals like spodumene and lepidolite. The process for ore-based extraction includes roasting, acid treatment to form lithium sulfate, and subsequent precipitation with sodium carbonate to isolate lithium carbonate. For brine sources, lithium chloride concentration via sun-drying, followed by precipitation with sodium carbonate, yields lithium carbonate.

What Is Sodium Carbonate?

Sodium carbonate, a white, hygroscopic powder, is an alkaline metal carbonate with the chemical formula Na₂CO₃. Known as soda ash, disodium carbonate, and anhydrous sodium carbonate, it is also referred to as soda carbonate or soda.

Uses of Sodium Carbonate

As a versatile raw material, sodium carbonate is integral to producing various chemical products, including carbonates like magnesium carbonate and barium carbonate, amino acids such as glutamic acid, food ingredients like soy sauce, and baking soda (sodium bicarbonate). Its applications extend to glass manufacturing for flat glass and water glass, and in the textile industry for cleaning cotton yarns and wool. Furthermore, sodium carbonate is utilized in dye production, soap powders, as a desulfurizing agent, in pulp processing, and pharmaceuticals.

Properties of Sodium Carbonate

An odorless, white solid, sodium carbonate exhibits hygroscopic properties, with a molecular weight of 105.99, a specific gravity of 2.533, and a melting point of 851°C. It absorbs moisture gradually from the air and starts to lose CO₂ at 400°C when heated, forming sodium bicarbonate (NaHCO₃) upon CO₂ absorption. A 1% aqueous solution has a pH of 11.3, showing alkalinity by ionizing and producing OH^– ions. Sodium carbonate forms a 10-hydrate below 32°C, a 7-hydrate between 32°C and 35°C, and a 1-hydrate above 35°C, with the 10-hydrate known as washing soda potentially decomposing to 1-hydrate when exposed to air.

Other Information on Sodium Carbonate

How Sodium Carbonate Is Produced

Sodium carbonate is manufactured through various methods, including the ammonia soda (Solvay) method, the sodium chloride soda method, and the caustic soda carbonation method. The Solvay method, which has been used industrially for many years, uses sodium chloride (NaCl), ammonia (NH₃), seawater, and limestone (CaCO₃) as raw materials. The production process involves brine purification to remove calcium and magnesium salts, ammonia absorption to create ammonia brine, carbonation to produce and precipitate sodium carbonate, and solid-liquid separation and calcination to convert sodium bicarbonate to sodium carbonate. This process efficiently recycles ammonia and converts NH₄Cl byproducts back to ammonia, showcasing an effective loop of resource utilization.

What Is Dimethyl Carbonate?

Dimethyl carbonate (DMC), an ester of carbonic acid with the formula C₃H₆O₃, is recognized for its flammable properties and is produced primarily in Asia, the Middle East, and Europe. Its use is restricted in consumer and indoor applications due to its flammability, though it is considered safer than some common industrial solvents.

Uses of Dimethyl Carbonate

Primarily used in polycarbonate production, dimethyl carbonate is used in creating materials with high impact resistance and optical clarity, such as DVDs, safety goggles, and automotive parts. It also serves as an electrolyte in lithium-ion batteries and in the formulation of paints, cleaners, and adhesives.

Properties of Dimethyl Carbonate

A colorless, flammable liquid, dimethyl carbonate has a low melting and boiling point, making it a versatile solvent with a low flash point. Its exposure limit is set to 100 ppm over an 8-hour workday, indicating the necessity for caution due to potential methanol poisoning upon ingestion.

Structure of Dimethyl Carbonate

The structure features methyl groups replacing the hydrogen atoms in carbonic acid, giving it a molecular weight of 90.08 g/mol and a specific density range.

Other Information on Dimethyl Carbonate

1. Synthesis of Dimethyl Carbonate

While traditionally synthesized from phosgene and methanol, modern methods utilize methanol, oxygen, and carbon monoxide catalytically. Industrial production may involve the esterification of ethylene or propylene carbonate with methanol.

2. Reaction of Dimethyl Carbonate

As a methylation agent, dimethyl carbonate offers a less toxic and more environmentally friendly alternative to traditional methylating agents. It can methylate a wide range of organic compounds under specific conditions, emphasizing its utility and versatility in chemical synthesis.