月: 2023年4月

What Is Sodium Periodate?

Sodium periodate, the sodium salt of periodate with the formula NaIO₄, is also known as sodium metaperiodate. Its CAS number is 7790-28-5. This compound exists alongside orthoperiodate, each serving distinct roles in chemical processes.

Uses of Sodium Periodate

As a powerful oxidizing agent, sodium periodate is critical in analytical chemistry for oxidizing reactions, notably the oxidative cleavage of glycols. This process breaks the covalent bonds between carbon atoms bonded to hydroxy groups, forming aldehydes and ketones.

Properties of Sodium Periodate

Sodium periodate is a white solid with a molecular weight of 213.89 and decomposes at 300°C. It is highly soluble in water but almost insoluble in organic solvents like ethanol. Its water solubility is 3.8 g/100 mL at 6°C, with a density of 3.865 g/mL.

Types of Sodium Periodate

Available in various quantities for research and development, sodium periodate is sold in 5g, 25g, 100g, and 500g packages. It remains stable under standard storage conditions and can be kept at room temperature.

Other Information on Sodium Periodate

1. Synthesis of Sodium Periodate

Synthesis involves dehydrating ortho-trisodium dihydrogen periodate (Na₃H₂IO₆) in nitric acid or reacting sodium iodate with chlorine or sodium iodide with bromine in a sodium hydroxide solution.

2. Chemical Reaction of Sodium Periodate

Utilized primarily as an oxidant in organic synthesis, sodium periodate’s solubility in water necessitates using auxiliary solvents for reactions with hydrophobic substrates. Its key reaction involves cleaving 1,2-diols to form aldehydes or ketones.

3. Hazard and Regulatory Information on Sodium Periodate

As an oxidizing solid (Category 2 under GHS classification), sodium periodate can exacerbate fires. It is stable when stored properly but can form explosive mixtures with reducing agents and fine metal powders. It is regulated by law due to these hazards, requiring careful handling and appropriate protective measures.

What Is Protein Hydrolysate?

Protein hydrolysate is a mixture of amino acids derived from the hydrolysis of proteins found in meat, fish, soybeans, and wheat. This process can be achieved through acid hydrolysis with hydrochloric acid, enzymatic hydrolysis using proteases, or thermal hydrolysis. Acid hydrolysis, while common, may produce potentially carcinogenic chloropropanols, prompting safety measures like setting maximum standard values for these compounds by the Codex Alimentarius Commission.

Uses of Protein Hydrolysate

Protein hydrolysates are utilized in both food and cosmetic industries.

1. Food Products

Used for seasoning in processed foods such as pickles, sauces, fish cakes, and instant noodles, protein hydrolysates impart flavor and richness without being classified as food additives under food safety laws.

2. Cosmetics

Applied in soaps and shampoos, they enhance foaming and moisturization. Notably, safety standards for wheat hydrolysates in cosmetics address past concerns over allergic reactions.

Properties of Protein Hydrolysate

Protein hydrolysates offer umami and richness, along with improved digestion and absorption, muscle recovery support, easy digestibility, and enhanced food flavor and texture.

1. Improved Digestion and Absorption

By breaking protein down into smaller peptides and amino acids, protein hydrolysates facilitate quicker and more efficient nutrient uptake.

2. Muscle Super-Recovery and Growth

The rapid digestion of hydrolyzed protein accelerates amino acid delivery to muscles, aiding in recovery and growth post-exercise.

3. Easy to Digest

These hydrolysates are gentle on the digestive system, making them suitable for nutritional supplementation, especially after intense physical activity.

4. Enhanced Flavor and Texture in Foods

Their composition can improve the taste and texture of food products, underpinning their use as seasonings and food additives.

Other Information on Protein Hydrolysate

Protein Hydrolysate Manufacturing Process

Derived from vegetable or animal protein sources, protein hydrolysates are produced mainly through acid digestion or enzymolysis.

Acid Digestion Method: This cost-effective method produces hydrolyzed vegetable protein (HVP) and hydrolyzed animal protein (HAP) but risks creating harmful chloropropanols. International safety standards mitigate these risks.

Enzymolysis Method: A safer alternative that avoids acid use and reduces bitterness, though it presents challenges in terms of technical complexity and costs, especially for animal proteins.

What Is Hydrogen Bromide?

Hydrogen bromide is a compound of bromine and hydrogen, a colorless gas with a pungent odor.

Its official name is hydrogen bromide, which is characterized by the white smoke it produces when exposed to air moisture. Hydrogen bromide is toxic and can damage the mucous membranes of the eyes and bronchial tubes and cause breathing difficulties.

Uses of Hydrogen Bromide

Hydrogen bromide is used as a raw material for synthesizing pharmaceuticals, hydrobromic acid, and various bromides, as well as a general-purpose reagent. In the chemical industry, it is used as an alkylation catalyst and reducing agent.

Additionally, hydrogen bromide serves as a high-quality semiconductor material gas and can be used as an etching or cleaning gas. Hydrobromic acid, an aqueous solution of hydrogen bromide, is an important chemical used as a catalyst in the production of terephthalic acid, a raw material for polyester fiber, and as a raw material for various bromates and alkyl bromides.

Properties of Hydrogen Bromide

Hydrogen bromide is corrosive and nonflammable. It has a density of 3.307 g/L, a melting point of -124° F (-86.80°C), and a boiling point of -87.48° F (-66.38°C).

As one of the halogenated hydrogens, it is a compound composed of hydrogen and bromine. Hydrogen bromide is a linear molecule with the chemical formula HBr and a molar mass of 80.912. Under low-temperature conditions, hydrogen bromide will form crystals of hydrate.

Hydrogen bromide is readily soluble in organic solvents with oxygen, such as ethanol and acetone. It is also well soluble in water, and its aqueous solution is a strong acid. The aqueous solution of hydrogen bromide is called hydrobromic acid. 47.63% hydrobromic acid is an azeotrope with a boiling point of 255.7° F (124.3°C).

A similar azeotrope, 48%, is commonly used commercially and is designated as a deleterious substance, not for medicinal use. Its heat of dissolution in water is ΔH° = -85.15 kJ/mol, the largest among hydrogen halides. It is a strong monovalent acid with properties similar to hydrochloric acid and is easily oxidized.

For example, it can be oxidized by air or decomposed by light to liberate bromine, which gives it a yellowish color. Furthermore, hydrogen bromide’s reducing effect is stronger than that of hydrogen chloride (HCl).

Other Information on Hydrogen Bromide

1. Synthesis of Hydrogen Bromide

Hydrogen bromide is produced by the reaction of hydrogen and bromine over a catalyst. Hydrogen bromide can be obtained by reacting bromide with phosphoric acid or by allowing bromine to act on a mixture of red phosphorus and water.

Various other synthetic methods are available on a laboratory scale. An example is the bromination of tetralin. Anhydrous hydrogen bromide can also be obtained by refluxing triphenylphosphonium bromide (Ph3PH+Br-) in xylene and thermally decomposing it.

However, unlike hydrogen chloride and hydrochloric acid, the scale of production of hydrogen bromide and hydrobromic acid is small. Early production methods involved the reaction of hydrogen and bromine at temperatures as high as 392-752° F (200-400°C), usually using platinum or asbestos as a catalyst in industrial reactions.

2. Reaction of Hydrogen Bromide

Hydrogen bromide is used to produce bromoalkanes with alcohols. Bromoalkanes can also be obtained by the addition of hydrogen bromide to alkenes.

The addition of hydrogen bromide to alkynes yields bromoalkenes, usually with stereochemistry in the anti form. The addition of hydrogen bromide to haloalkenes follows Markovnikov’s rule, yielding gem-dihaloalkanes.

Hydrogen bromide is also used in the synthesis of bromoacetals as well as in the ring-opening reactions of lactones and epoxides. Hydrogen bromide can be used as a catalyst in a wide variety of organic reactions.

What Is Ethyl Bromide?

Figure 1. Basic Information on Ethyl Bromide

Ethyl bromide, also known as bromoethane, is a halogenated hydrocarbon with the chemical formula C₂H₅Br.

It is classified under various laws due to its hazardous and toxic nature. Under the Industrial Safety and Health Law, it is labeled as hazardous and toxic, needing notification, and classified as a flammable substance. The Labor Standards Law identifies it as a disease-causing chemical substance, while the Poisonous and Deleterious Substances Control Law and the Fire Service Law categorize it as a deleterious substance and a hazardous material, respectively. Protective equipment is essential when handling ethyl bromide.

Uses of Ethyl Bromide

As an ethylating agent in organic synthesis, ethyl bromide is used to create ethyl esters from carboxylates and synthesize ethylamine by ethylating amines. It also serves as a raw material for the indispensable Grignard reagent in organic synthesis and is utilized in pharmaceutical manufacturing, including anesthetics.

Properties of Ethyl Bromide

With a melting point of -119°C and a boiling point of 38.4°C, ethyl bromide is a colorless, volatile liquid with an ethereal odor. It is highly flammable, with a flash point below -2°C, and has an explosive range of 6.8-8.0%. Insoluble in water, it dissolves slightly at 20°C and is soluble in organic solvents like ethanol and benzene. Exposure to ethyl bromide can cause severe irritation and poisoning symptoms upon inhalation, skin contact, or eye exposure.

Structure of Ethyl Bromide

Abbreviated as EtBr, ethyl bromide is formed by replacing one hydrogen atom in ethane with a bromine atom. It has a molecular weight of 109.0 g/mol and a density of 1.4 g/cm³.

Other Information on Ethyl Bromide

1. Synthesis of Ethyl Bromide

Figure 2. Synthesis of Ethyl Bromide

Synthesis typically involves the addition of hydrogen bromide to ethylene, or distillation of ethanol with hydrobromic acid and a small amount of sulfuric acid, also producing diethyl ether as a byproduct. Alternatively, ethyl bromide can be produced from ethanol using thionyl bromide (SOBr₂) or phosphorus tribromide (PBr₃).

2. Reaction of Ethyl Bromide

Figure 3. Reaction of Ethyl Bromide

Ethyl bromide reacts with alkali to form ethylene and is a cost-effective reagent for preparing Grignard reagents. In organic chemistry, it serves as a superior alkylating agent compared to ethyl chloride, facilitating the synthesis of ethyl esters, ethylation of pseudo-carbanions, and production of ethylisothiouronium salts and ethylamine.

What Is Iron Nitride?

Iron nitride, a compound of iron and nitrogen, exists in various crystal forms such as Fe2N, Fe4N, and Fe16N2. Its properties and crystal structure vary with the nitrogen content, leading to different magnetic characteristics.

Iron nitride combines metal-like and oxide-like properties, offering superior corrosion resistance, weather resistance, and hardness compared to metallic iron. Fe4N, in particular, exhibits ferromagnetic properties at room temperature, with a Curie temperature around 914°F (490°C).

Uses of Iron Nitride

Iron nitride is used for surface hardening of steel and other materials due to its high hardness and corrosion resistance. Commonly used in aircraft parts and cookware, it undergoes a nitriding process to improve wear resistance. It’s also a promising material for permanent magnets, potentially replacing expensive neodymium magnets in various applications.

Surface treatment techniques like gas nitriding, salt bath nitriding, and ion nitriding are used to incorporate iron nitride into various products.

Properties of Iron Nitride

1. High Hardness

Iron nitride’s high hardness, much greater than ordinary steel, is due to solid solution strengthening by nitrogen. This atomic distortion inhibits dislocation movement, increasing the material’s strength.

2. Rust Resistance

Iron nitride’s enhanced corrosion resistance makes it more rust-resistant than standard steel, attributed to its unique composition and structure.

3. Ferromagnetism

Fe4N and Fe16N2, among iron nitrides, are notable for their high saturation magnetization and ferromagnetic properties, making them suitable for use in magnetic materials. They are also considered rare earth-free magnets, with Fe16N2 offering a strong magnetic force due to its unique crystal structure.

What Is Lead Sulfate?

Lead sulfate is an inorganic compound consisting of lead sulfate and lead ions combined with the chemical formula PbSO₄.

It has a mass of 303.26 g/mol, a density of 6.29 g/cm³, and a density of 1170°C. At normal temperature and pressure, it has the appearance of a white solid.

Uses of Lead Sulfate

1. Lead-acid batteries

Lead sulfate is used as a cathode and anode active material for the electrodes of lead-acid batteries. The relatively low cost of lead as an electrode material makes it possible to manufacture storage batteries with high-cost performance. Lead dioxide is used as the electrode for the positive electrode and lead for the negative electrode, and lead sulfate has been used as the electrolyte for both.

Dilute sulfuric acid is ionized by water to SO₄²- and H⁺, which reacts with sulfate ions to form lead sulfate, PbSO₄, at the negative electrode. Lead sulfate adheres to the surface of the anode in solid form, and the mass of the anode increases rapidly. In addition, electrons generated by the oxidation of lead are transferred to the cathode through conductors.

In addition, hydrogen ions are also released into the electrolyte, and the hydrogen ions are directed to the cathode, where free electrons have gathered, and move through the electrolyte, which is the principle of the battery. The cathode plate, on the other hand, accepts the free electrons and hydrogen ions from the anode and undergoes a chemical reaction with lead dioxide and dilute sulfate. As a result, lead Sulfate and water are formed, and the lead sulfate adheres to the cathode plate in the same manner as the anode plate.

The lead sulfate and other substances adhering to the surface of the cathode plates due to discharge cause a recharging reaction that returns the battery to the state it was in before discharge, allowing it to be used repeatedly. The positive electrode is oxidized to lead oxide (IV) by recharging, and the negative electrode is reduced to solid lead, which is a property of lead-acid batteries.

2. Pigment

Lead sulfate has been used as a white pigment in various situations since ancient times because of its white color. Lead sulfate has also been found in the treasures of the Shosoin Repository in Nara, Japan.

Lead sulfate is also characterized by its use as one of the raw materials for coloring pigments such as yellow lead and molybdate orange. However, in recent years, there has been a growing movement toward the elimination of lead-containing paints due to concerns about the adverse effects of lead-containing paints on the human body.

3. Other

Other applications include glazes, catalysts, and resin stabilizers.

Properties of Lead Sulfate

1. Physical Properties

It is a white or colorless, crystalline or crystalline powder solid in appearance. It is soluble in excess alkali hydroxide as lead hydroxide ions, but its solubility in water is almost negligible at 0.0425g/1L at 25℃. It is also insoluble in organic solvents such as ethanol and acetone.

The crystal structure is stable with a barium sulfate-type structure and a rectangular crystal structure. Its melting point is 1,170°C, but decomposition begins at around 1,000°C. It decomposes to lead(II) oxide or lead(III) tetroxide while generating sulfur dioxide and sulfur trioxide.

2. Lead Sulfate Manufacturing Process

Lead sulfate is produced by the reaction of a water-soluble lead compound with a strong acid, such as lead sulfate and lead nitrate, or lead sulfate and lead acetate, accompanied by heating. Lead sulfate is obtained as a white precipitate.

In addition, a paste made by adding dilute sulfate to lead(II) oxide is used as the active material in lead-acid batteries, which contains various basic salts with compositions such as PbSO₄·PbO、PbSO₄·2PbO、PbSO₄·3PbO、PbSO₄·4PbO. In addition, water is a byproduct of this reaction.

When lead sulfate reacts with lead, lead sulfate and hydrogen are formed, but a film of insoluble salts is formed on the surface of the reactants, which must be heated to facilitate the reaction.

Other Information on Lead Sulfate

Hazards of Lead Sulfate

Lead sulfate is highly toxic and may cause cancer, harm the fetus in pregnant women, and damage the organs (kidneys, nervous system, digestive system, and blood system). Therefore, it is necessary to wash hands thoroughly and wear rubber gloves, lab coats, masks, and protective goggles when handling it.

In addition, because of its harmful effects on aquatic organisms, its release into the water is strictly regulated.

What Is Iron Sulfate?

Iron sulfate is an inorganic compound with the chemical formula FeSO₄.

It is also called Ferrous Sulfate (II) or Ferrous Iron Sulfate. It is nonflammable, but heating can cause it to become corrosive and produce toxic fumes and vapors.

Iron sulfate is used in the manufacture of flagella, black ink, and pigments, and can be used as a magnetic material, reducing agent, water purifier, mordant, disinfectant, and antiseptic. Iron sulfate (II) is a food additive, and when used in foods, it is labeled as “Iron Sulfate” or “Ferrous Sulfate.

Uses of Iron Sulfate

As a food additive, iron sulfate can be used to prevent color development and discoloration of fruits and vegetables. In addition, it can be found in supplements and nutritional drinks as a nutrient fortifier to provide iron.

Iron is also one of the trace elements necessary for plant growth. It is added to fertilizers to supply iron during plant growth and is used as a raw material for foliar spray solutions. It can also be used as a chemical for wastewater treatment plants using the chemical oxidation method (Fenton process) during coagulation treatment.

Iron sulfate reacts with nitric oxide to form an unstable brown compound. Therefore, it can be used to detect nitrite and nitrate ions.

Properties of Iron Sulfate

Iron sulfate has a pale blue-green appearance and is a crystalline or crystalline powder solid. It is soluble in water, with 26.6 g of the anhydrous form dissolved in 100 g of 20°C water. However, it is virtually insoluble in ethanol. Aqueous solutions are green in color and gradually oxidize. Oxidation is accelerated in alkaline and ethanol solutions.

Iron sulfate is an oxidizable substance. Oxidizability is a property that allows it to be oxidized by oxidizing substances.

Structure of Iron Sulfate

The formula for anhydrous iron sulfate is 151.92. It is also available in 1, 4, 5, and 7 hydrates. Naturally occurring are 1, 5, and 7 hydrates. The 7-hydrate is called melanterite and has the chemical formula FeSO₄・7H₂O. When anhydrate is exposed to moist air, it changes to septahydrate.

Other Information on Iron Sulfate

1. Synthesis of Iron Sulfate (II)

The reaction of iron sulfate with iron produces hydrogen, yielding iron sulfate. Aqueous solution obtained by air oxidation of pyrite (FeS₂) moistened with water can be crystallized at temperatures below 56°C to produce heptahydrate.

Above 56°C, tetrahydrate crystallizes, and above 64°C, monohydrate is produced. Evaporation and concentration of this solution in a vacuum with excess sulfuric acid yields the pentahydrate.

2. Synthesis of Iron Sulfate (III)

In addition to iron sulfate (II), iron sulfate (III) also exists. Iron sulfate (III), also called ferric iron sulfate, is an anhydrate with the formula Fe₂(SO₄)₃ and the formula weight is 399.9. Iron sulfate (III) is available in 3, 6, 7, 7.5, 9, 10, and 12 hydrates, with 7, 7.5, 9, 10, and 12 hydrates occurring in nature.

When an aqueous solution of iron (II) Iron Sulfate is oxidized and concentrated by evaporation, crystals of hydrated iron (III) Iron sulfate can be produced. However, the number of crystalline waters depends on the conditions of crystallization. Heating and dehydration of the hydrate yields iron (III) iron sulfate anhydrate, a white or pale yellow powder.

3. Properties of Iron Sulfate (III)

Iron sulfate (III) anhydrate is deliquescent and decomposes when heated to approximately 480°C, yielding iron oxide. Slightly soluble in water, it takes on a brown color by hydrolysis, and upon warming, a reddish-brown precipitate of basic iron sulfate (III) or iron (III) hydroxide oxide is immediately formed.

Iron sulfate (III) can be used to produce iron alum and Prussian blue. It is also used as a mordant and in pharmaceuticals.

4. Characteristics of Iron (III) Iron (II) Sulfate

Iron (III) sulfate (II), also called ferric ferrous iron sulfate, has the chemical formula Fe^IIFe^III₂(SO₄)₄. The formula quantity is 551.81.

It is obtained as a reddish-brown powder when a mixture of iron sulfate (II) and acid iron sulfate (III) is exposed to air and occurs naturally as a hydrate. When dissolved in water, it decomposes, and iron sulfate (II) precipitates.

What Is Lithium Sulfate?

Lithium sulfate is an inorganic compound with the chemical formula Li2SO4, formed by the reaction of sulfuric acid with lithium or its compounds such as lithium hydroxide or lithium oxide, resulting in lithium sulfate and water.

It appears as a white, crystalline powder and is soluble in water but almost insoluble in ethanol. Lithium sulfate is hygroscopic and should be stored in a dry environment to prevent moisture absorption.

This nonflammable compound can produce corrosive or toxic fumes when heated.

Uses of Lithium Sulfate

Lithium sulfate is used as an electrode material in aqueous lithium-ion batteries, utilizing its solubility in water. These batteries are under research and development for being safer alternatives to conventional lithium-ion batteries, minimizing risks of ignition or explosion. Additionally, lithium sulfate is used as a hardening accelerator in cement, promoting faster hydration and solidification.

What Is Silver Sulfide?

Silver sulfide (Ag₂S), also known as silver(I) sulfide or galena, is a naturally occurring mineral with significant applications and safety considerations. It forms when silver contacts sulfur vapor or reacts with hydrogen sulfide in the air, commonly resulting in silver tarnish.

Uses of Silver Sulfide

Utilized in the manufacturing of silver, and ceramics, and as a colorant in sepia-toned photography, silver sulfide’s industrial uses have evolved with technology. Despite the decline in photographic film use, it remains relevant in modern applications like plasma displays and solar power transmission.

Properties of Silver Sulfide

This compound is a gray-to-black solid that is insoluble in water and dilute acids but soluble in concentrated sulfuric acid, nitric acid, and potassium cyanide solution. Notably photosensitive, silver sulfide films exhibit the photoelectric effect under visible light.

Structure of Silver Sulfide

Silver sulfide exists in three crystal forms: α-type (argentite), β-type (acanthite), and γ-type, each with distinct stability and structure. Argentite, stable at higher temperatures, transitions to acanthite at lower temperatures, with γ-type being an unnatural, high-temperature form.

Other Information on Silver Sulfide

1. Production and Corrosion

Naturally found as argentite, silver sulfide forms on silver surfaces as tarnish due to air exposure. Innovative cleaning methods involve reactions with aluminum and salt to restore silver items.

2. Safety Information

Handling silver sulfide requires caution due to its potential to produce toxic hydrogen sulfide gas and explosive mixtures with metal halides. Adequate ventilation and protective gear are essential during heating processes to mitigate exposure to harmful byproducts like sulfur dioxide.

What Is Lead Sulfide?

Lead sulfide (PbS), also known as galena, is an inorganic compound combining lead and sulfur. It forms naturally as a tetrahedrite mineral and is subject to strict regulatory classifications due to its toxic byproducts when heated.

Uses of Lead Sulfide

Employed in the production of pigments, paints, ceramic glazes, and lubricating oils, lead sulfide’s use has been reconsidered due to lead’s harmful effects. It serves as a primary source of lead and contributes to chemical conversion processes.

Properties of Lead Sulfide

Lead sulfide exhibits a melting point of 1,114°C and a boiling point of 1,281°C. It is low in solubility, posing risks when thermally decomposed. Its black cubic crystals demonstrate semiconducting properties, being used in older semiconductor technologies.

Structure of Lead Sulfide

Its sodium chloride-type crystal structure features octahedral coordination and has been explored in nanoparticles and quantum dots for potential solar cell applications.

Other Information on Lead Sulfide

1. Synthesis of Lead Sulfide

Formation occurs when hydrogen sulfide or sulfide ions are introduced to lead ion solutions, creating a black precipitate. This reaction’s high equilibrium constant facilitated its use in qualitative inorganic analysis.

2. Applications of Lead Sulfide

Lead sulfide’s sensitivity to infrared radiation makes it valuable in sensor elements, detecting radiation wavelengths from 1 to 2.5 µm at room temperature, with the range extending when cooled.

3. Characteristics of Lead Sulfide (IV)

Lead(IV) sulfide (PbS₂) emerges under high pressure and temperature conditions, presenting as a p-type semiconductor with potential thermoelectric material uses.