投稿者: yako77

What Is Sodium Persulfate?

Sodium persulfate, also known as sodium luoxodisulfate or sodium persulfate, is a substance with the molecular formula Na2S2O8.

Sodium persulfate has two types: peroxomonosulfate (molecular formula: H2SO5) and peroxodisulfate (molecular formula: H2S2O8), but the term sodium persulfate generally refers to the divalent sodium salt of peroxodisulfate. The CAS number 7775-27-1, which is a unique number for a chemical substance, is assigned to sodium persulfate. The molecular weight is 238.1 g/mol.

At room temperature and pressure, it exists in a white crystalline state and has a slightly pungent odor. Its solubility in water is 556 g/L at 20°C, but it is difficult to dissolve in ethanol and is easily degraded in ethanol. Aqueous solutions are neutral or slightly acidic. No boiling point or melting point is observed, and when heated, it decomposes at temperatures above approximately 180°C.

Uses of Sodium Persulfate

Sodium persulfate is used industrially for its use as a strong oxidizing agent. Specifically, it is used as a polymerization initiator for synthetic resins and fibers, as an etching agent for printed circuit boards, and as a surface treatment agent for metals.

Among these, it is most commonly used as a polymerization initiator for synthetic resins and as an initiator in radical polymerization reactions. Radical polymerization reaction is a type of polymerization reaction in polymer chemistry, in which polymer chains are elongated by radicals as reaction centers.

The decomposition of sodium persulfate produces sulfate radicals, which in turn draws hydrogen or electrons to initiate a chain polymerization reaction. This process yields polymers such as polyethylene, polyolefin, and polystyrene.

One application that has been attracting attention in recent years is the use in the oxidative decomposition of toxic substances. Examples include the decomposition of ammonia nitrogen, which causes eutrophication in wastewater, and decomposition of halogenated hydrocarbons, which are soil pollutants. Sodium Persulfate’s strong oxidizing power and the fact that the product of decomposition is sulfate ions, which are abundant in the natural environment, makes it suitable for these applications.

Properties of Sodium Persulfate

Sodium persulfate and other peroxo-sulfates are unstable and easily reduce themselves to generate sulfate oxides, which are oxidizing agents. They are unstable with respect to heat and temperature and decompose when heated, producing toxic and corrosive fumes (e.g., sulfur oxides).

It is also highly reactive, with strong flammable and reducing substances, metallic powders, and strong bases. When in contact or mixed with alcohol, it decomposes, separating the oxygen and producing sulfur dioxide, which is highly poisonous. Due to the nature of the oxygen produced during decomposition, it is not itself flammable, but it helps other substances to burn.

Other Information on Sodium Persulfate

Safety of Sodium Persulfate

In terms of safety for humans and animals, its oral toxicity is not high, being class 4 of the GHS classification, but it is highly irritating to the respiratory organs and skin due to its oxidizing power. In addition, decomposition products and mists containing decomposition products may be highly toxic. Therefore, appropriate protective equipment, including respiratory protection, must be worn during use, the storage environment must be prepared to prevent unexpected decomposition, and handling must be conducted in a manner that avoids mixing with other products.

From the viewpoint of preventing fires and explosions, they are oxidizing solids that help combustion when they come into contact with combustibles. In addition, it reacts violently with metals and reducing substances. Therefore, mixing with these substances must be avoided.

What Is Potassium Persulfate?

Potassium persulfate is a sulfur oxoacid, a type of persulfate.

It is represented by the molecular formula K₂S₂O₈ and has a molecular weight of 270.32 g/mol. It is also known as potassium peroxodisulfate. The CAS number, which is a unique chemical number, is 7727-21-1.

It is generally known to be produced by the reaction of ammonium persulfate and potassium hydroxide in an aqueous solution, a process that is still used today. At normal temperature and pressure, it exists as a white to slightly light yellowish crystal state and is odorless.

Its solubility in water is 5.2g/100ml at 20℃, but it is soluble in hot water and almost insoluble in ethanol.

Uses of Potassium Persulfate

Potassium Persulfate is mainly used in the following applications:

• Print etching agent
• Metal surface treatment agent
• Starch modifier
• Polymerization initiator for synthetic resins and fibers
• Soil conditioner
• Bleaching agent for natural products
• Synthetic oxidizers for pharmaceuticals

Etching agents for printed circuit boards are agents that corrode metals and metal oxides, and are mainly used as a surface treatment method to remove the surface of metals, glass, and semiconductors using their own corrosive properties. Etching is used not only in the manufacture of printed circuit boards but also in the processing of semiconductors and MEMS, because it can perform more precise processing in a batch than cutting or polishing.

Potassium persulfate is a powerful yet slow-reacting oxidant. It is still used today as a polymerization initiator in the synthesis of phenol, aromatic amines, and aromatic hydrocarbons. Potassium persulfate acts as an initiator in emulsion polymerization, an industrially important aqueous polymerization process.

Emulsion polymerization is a process in which insoluble monomers are mixed to form spherical micelles in a surfactant, which are then polymerized by heating with the addition of a polymerization initiator, such as potassium persulfate. This method is suitable for mass production in factories because it eliminates the heat generated during the polymerization reaction and keeps the viscosity of the system low.

Potassium persulfate is used in oxygen bleaches to bleach and clean natural products. Because it is a strong base, oxygen bleach is highly resistant to yellowing caused by grease and sebum.

Properties of Potassium Persulfate

Potassium Persulfate, when mixed with combustibles or organic materials, it decomposes by heat, impact, or friction and acts as a strong oxidizer that causes severe combustion.

When heated, it decomposes to produce sulfurous acid gas, which is gaseous sulfur dioxide. Sulfurous acid gas is a colorless, toxic gas with a pungent odor.

Inhalation of sulfurous acid gas can cause severe irritation to the respiratory system and may cause asthma. It also has the property of reacting violently with strong bases. In terms of stability, it should be prevented from exposure to high temperatures, direct sunlight, heat, and static electricity, as it may be altered by light.

Other Information on Potassium Persulfate

Handling and Storage Precautions

When handling or storing potassium persulfate, the following precautions should be taken:

• Avoid contact with combustibles and reducing agents.
• Do not use high-temperature materials in the vicinity.
• The storage area should have fire-resistant walls, columns, and floors, and the beams should be made of noncombustible materials.
• Roofs of storage areas should be made of noncombustible materials and should not have ceilings.
• Store containers tightly closed in a cool, well ventilated, light-shielded area.

What Is Thallium Sulfate?

Thallium sulfate is the sulfate salt of thallium.

It is a colorless crystalline powder with no taste or odor. It is soluble in water and ethanol and is also used in liquid form.

Thallium sulfate is classified as a deleterious substance and must be stored and used with care. It has acute and chronic toxicity, affecting the gastrointestinal tract, nervous system, respiratory organs, and kidneys when ingested orally.

It has also been shown to be toxic for reproduction, and may affect the development of testes and fetuses. Because of these toxic effects, thallium sulfate was used as a rat poison, but is no longer used.

Uses of Thallium Sulfate

Thallium sulfate was once used as a rat poison. Because it is soluble in water, it is easy to prepare poison baits, and since rats eat it without avoiding it, poison baits were prepared by adding a solution of thallium sulfate to the food preferred by rats.

Thallium sulfate is not excreted but accumulates in the body of rats, so even if an individual does not eat a lethal dose at once, it will die by continuous ingestion of the poisoned food. In addition, its reproductive toxicity suppresses the reproduction of rats and keeps the population low over the long term.

Rodenticides containing thallium sulfate were previously registered as pesticides, but the registration was revoked due to its high toxicity and low distribution volume. Since the pesticide registration of thallium sulfate expired, other ingredients such as zinc phosphide, coumarin, and difethialol have been used in rodenticides.

Characteristics of Thallium Sulfate

Thallium sulfate is the sulfate salt of thallium, with the chemical formula Tl2SO4. Thallium sulfate is a colorless crystal that is stable at room temperature, and when dissolved in water, it ionizes into thallium (univalent) and sulfate ions.

The raw material thallium is a group 13 metallic element that is recovered as a byproduct of the refining process of copper, lead, and zinc. Thallium exists mainly as a monovalent ion, but when oxidized, trivalent ions may be produced to form thallium oxide, etc.

The basic properties of thallium sulfate (molecular weight, specific gravity, and solubility) are as follows:

• Molecular weight: 504.83
• Specific gravity: 6.77
• Solubility: Soluble in water (4.87 g/100 mL at 20°C)

Other Information on Thallium Sulfate

1. Toxicity to Humans

Thallium sulfate is toxic to humans. Ingestion due to accidents or incidents in the past has been reported to cause anorexia, vomiting, abdominal pain, bloody stools, etc., followed by abnormal limb perception, hallucinations, convulsions, tachycardia, hair loss, and other symptoms. In severe cases, death occurs due to kidney and central nervous system abnormalities and heart failure.

To prevent accidental ingestion, containers containing thallium sulfate must be clearly labeled with the name of the substance. Storing thallium sulfate in containers such as those used for food or handling it while eating or drinking increases the risk of accidental ingestion or ingestion and is very dangerous.

Since experiments on rats have confirmed that the original (unformulated pure product) of thallium sulfate is also percutaneous toxic, care must also be taken to avoid skin contact. Wear protective equipment such as nitrile gloves and protective glasses, and wash thoroughly with water if it adheres to the skin. If it gets into the eyes, rinse well under running water and seek medical attention.

2. Decomposition by Heating and Oxidation

When thallium sulfate is heated, it decomposes to produce fumes such as toxic thallium and sulfur oxides. Fumes are fine particles of evaporated or sublimated substances that condense in the air. Fumes are spread over a wide area as smoke or aerosols, so there is a risk of inhalation by workers. Thallium sulfate is also toxic in fumes, so if there is a risk that thallium sulfate may be heated in experiments, etc., measures such as handling it with ventilation in a draft are necessary.

Thallium sulfate reacts violently with oxidants to form oxides. The reaction heat during oxidation may produce toxic fumes, so care should be taken to store and use thallium sulfate in such a way that it does not come into contact with oxidants.

4. Environmental Impact

Thallium sulfate is toxic to wild birds and aquatic organisms, and must be prevented from leaking into the environment. When disposing of thallium sulfate, follow the standards set by the local government or outsource disposal to a specialized contractor.

What Is Zinc Sulfide?

Zinc sulfide is a sulfide of zinc represented by the chemical formula ZnS.

Zinc sulfide is a white or yellow powder or crystal with a density of 4.0 g/cm3, a melting point of 1,718°C, and a sublimation point of 1,180°C. It occurs naturally as sphalerite or zinc-blende and rarely as wurtzite.

Generally, it exists as a stable cubic form and is produced as sphalerite. The hexagonal form is obtained synthetically, but also occurs naturally as wurtzite.

Uses of Zinc Sulfide

Zinc sulfide is used as a raw material for phosphors, paints, rubber pigments, lithopons, leather, dental rubber, X-ray screens, and semiconductor laser crystal materials. Zinc sulfide with appropriate impurities has long been used as a silicophore because it emits silica light when irradiated with ultraviolet light.

The color of the light emitted can be changed depending on the type of impurity, and because it also emits light when exposed to an electron beam, it is applied to the silica-light surface of cathode-ray tubes in televisions and other equipment. When mixed with small amounts of radium or thorium, it is also used as a luminous paint for watches.

Properties of Zinc Sulfide

When Zinc sulfide is moist, it is gradually oxidized in air to zinc sulfate. Zinc sulfide is insoluble in water and alkalis and soluble in mineral acids. Newly made zinc sulfide is soluble in acids.

Naturally occurring sphalerites and wurtzites are semiconductors with large intrinsic band gaps; the band gap values at 300 K are 3.91 eV for wurtzites and 3.54 eV for sphalerites.

Zinc sulfide is a covalent compound with the composition ZnS. At approximately 1,293 K, a transition from a zinc sphalerite-type to a wurtzite-type crystal structure occurs. The melting point of the sphalerite form of Zinc sulfide is 1,991 K. The standard enthalpy of formation at 298 K is -204.6 kJ/mol.

Other Information on Zinc Sulfide

1. Synthesis of Zinc Sulfide

Zinc sulfide is produced by the direct compounding of sulfur and zinc. Zinc sulfide can also be obtained by blowing hydrogen sulfide into an aqueous solution containing zinc ions.

2. Zinc Sulfide in Atomic Physics

In early atomic physics, Ernest Rutherford and his colleagues used zinc sulfide as a scintillator, a phosphor material. Zinc sulfide emits light when excited by radiation such as alpha rays, X-rays, and electron beams. Zinc sulfide is therefore useful as a sensitizer for X-rays and as a material for cathode ray tubes. In the presence of impurities, it becomes phosphorescent and emits blue light and ultraviolet light.

Since automatic measurement was difficult with the technology of the time, Rutherford et al. used zinc sulfide powder to count the luminescence by eye in a dark room. They proved the existence of nuclei by applying the technique to the experiment of Rutherford scattering, in which alpha rays are irradiated onto a material. Zinc sulfide is still useful as an element for alpha-ray detection.

3. Zinc Sulfide as a Light-Storing Agent

Zinc sulfide can be used as a phosphorescent agent. Adding a few ppm of activator makes it useful for cathode ray tubes and X-ray screens, as well as for components that glow in the dark. For example, the light emitted will be bright blue when silver is used as an activator and yellow when manganese is used.

A well-known phosphorescent agent is copper, which emits light for a long time and has a greenish color. Zinc sulfide doped with copper is also used in electroluminescence panels.

4. Other Applications of Zinc Sulfide

Zinc sulfide is also used as an optical element for infrared light. It transmits visible light to wavelengths above 12 μm and can be used as flat optical windows or lenses.

Furthermore, it can be used as both a P-type and N-type semiconductor through doping, an unusual property for a group II-VI semiconductor.

What Is Manganese Sulfide?

Manganese sulfide is a compound of manganese and sulfur.

It occurs in minerals such as alabandite and rambergit. Manganese sulfide is generally found in the monosulfide or disulfide state. In addition, Manganese Sulfide (II) has three transformations: α, β, and γ.

A similar name is manganese sulfate, but it is a completely different compound with or without oxygen.

Uses of Manganese Sulfide

Manganese sulfide is mainly used as an additive to improve the machinability of sintered parts in the field of powder metallurgy.

Powder metallurgy is a manufacturing process in which metal powders are formed and sintered to produce metal products. Small motor parts for washing machines, fans, hard disks, etc. are examples of products processed by this powder metallurgy process.

Properties of Manganese Sulfide

• Manganese Sulfide (II) Alpha Form 
  It is a green cubic crystal. Its melting point is 1,620℃ and it is antiferromagnetic.
• Manganese Sulfide (II) Beta Form
  Red cubic crystal
• Manganese Sulfide (II) Gamma Form
  Pale red cubic crystal. p-type semiconductor at 700℃.

Among manganese sulfide (II), β- and γ-forms are unstable. The β and γ forms are unstable in manganous manganese sulfide (II) and are quickly oxidized to the α form. When used in powder metallurgy, the stable α-form is used.

Manganese sulfide (IV), on the other hand, is a blackish-brown cubic crystal. It is anti-ferromagnetic.

Structure of Manganese Sulfide

Manganese sulfide (II) has the chemical formula MnS and a molecular weight of 87.00. The alpha form of manganese sulfide (II) has a sodium chloride type structure with a Mn-S distance of 0.261 nm and a density of 4.05 g/cm3.

The beta form of Manganese Sulfide (II) has a zinc shear zinc ore type structure with a Mn-S distance of 0.243 nm and a density of 3.27 g/cm3.

Manganese sulfide (II) has a wurtzite-type structure with a Mn-S distance of 0.241 nm and a density of 3.26 g/cm3.

On the other hand, manganese sulfide (IV) has the chemical formula MnS2, with a molecular weight of 119.07. It has a pyrite-type structure. Its density is 3.463 g/cm3, Mn-S distance is 0.259 nm, and S-S distance is 0.209 nm.

Other Information on Manganese Sulfide

1. How Manganese Sulfide (II) Is Produced

Manganese sulfide (II) is also called manganese monosulfide. The alpha form of manganese sulfide (II) occurs naturally as sphalerite. Manganese sphalerite is a mineral that contains cubic manganese (II) sulfide.

Sphalerite is also called manganite sulfide or arabite. The alpha form of Manganese Sulfide (II) can be obtained by boiling an aqueous solution of manganese (II) chloride in the presence of a small amount of potassium oxalate, adding a slight excess of ammonia water, and passing hydrogen sulfide through it. The beta form of manganese sulfide (II) can be formed by passing hydrogen sulfide through an aqueous solution of manganese (II) acetate when cold.

The gamma form of manganese sulfide (II) can be obtained as a precipitate by boiling an aqueous solution of manganese chloride (II), adding ammonium chloride, and passing hydrogen sulfide through the solution while adding ammonia water.

2. Method of Producing Manganese Sulfide (Iv)

Manganese sulfide (IV) is also called manganese disulfide. It occurs naturally as a hauerite. Manganese sulfide (IV) can be obtained by adding sulfur and potassium polysulfide to an aqueous solution of manganese (II) sulfate and heating in a sealed tube.

When heated, manganese sulfide (IV) decomposes to release sulfur. Manganese sulfide (IV) reacts with hydrochloric acid to form manganese chloride (II).

What Is Silicon Tetrachloride?

Silicon tetrachloride is an inorganic compound consisting of silicon (Si) bonded with four chlorines.

It is also known as silicon chloride, silicon tetrachloride, tetrachlorosilane, and silicon tetrachloride. Although silicon tetrachloride exists as a liquid at room temperature, it quickly volatilizes upon heating due to its low boiling point of 57.6°C.

Uses of Silicon Tetrachloride

Silicon tetrachloride is rarely used in its raw state. It is basically used as a raw material for other silicon compounds.

1. High-Purity Silicon Tetrachloride

It is used as a raw material for silicon single crystals, for epitaxial growth of silicon wafers, for etching gas and other semiconductor fields, for synthetic quartz, and for synthetic quartz glass. Synthetic quartz glass has high purity and low metallic impurities. Besides, it allows light to pass through well and is resistant to heat, so it is used in photomasks for optical fibers and semiconductors.

2. General-Purity Silicon Tetrachloride

It is used as a raw material for silicon oxide (silica), which is used as a reinforcing filler for resins, CMP slurry for semiconductor polishing, adhesives, and viscosity adjusters for paints. It is also used as a raw material for various organic silicones (silane coupling agents, silicone resins, etc.).

Characteristics of Silicon Tetrachloride

The molecular formula of silicon tetrachloride is SiCl4, and its molecular weight is 169.89. It has a specific gravity of 1.52, a melting point of -70°C, and a boiling point of 57.6°C. At room temperature and pressure, it is a colorless, viscous liquid. It also has a pungent odor that can be suffocating. It is soluble in ether, benzene, chloroform, and carbon tetrachloride.

It reacts violently with water, strong oxidizers, strong acids, alcohols, bases, ketones, and aldehydes to form toxic and corrosive hydrogen chloride (HCl). In humid air, it hydrolyzes instantly to produce white smoke containing chlorine gas.

In the presence of water, the hydrochloric acid produced by hydrolysis corrodes many metals. For this reason, the metals that can be used are limited to nickel steel and copper-nickel alloys. Polyethylene, polyvinyl chloride, and Teflon can be used as resins.

Other Information on Silicon Tetrachloride

1. How Silicon Tetrachloride Is Produced

It is produced by heating silicon metal and chlorine or hydrogen chloride, or by chlorinating calcium silicide or other materials. Raw materials of a purity corresponding to the product purity required must be used.

Chlorination of metallic silicon: Si + 4HCl → SiCl4 + 2H2
Chlorination of calcium silicide: CaSi2 + 5Cl2 → 2SiCl4 + CaCl2

Research has also been reported on the production of Silicon Tetrachloride from silicate biomass such as rice chaff and rice straw.

2. Safety of Silicon Tetrachloride

Handling
Silicon tetrachloride is a severe irritant when adhered to skin and mucous membranes, and may cause erythema, edema, severe conjunctivitis, and coughing. When handling, wear a protective mask, impervious protective gloves, protective glasses with side plates, and long-sleeved work clothes.

In the event of a fire, heat, flames, and water used to extinguish the fire will generate hydrogen chloride gas, which is corrosive and highly toxic, and will emit very thick smoke, so care should be taken. If there is no danger, it is recommended to take measures such as moving the container away from the fire location.

What Is Polyvinyl Alcohol?

Polyvinyl alcohol is a type of water-soluble synthetic resin.

It was invented in Germany in 1924. It was invented in Germany in 1924 and has since been industrially developed by Japanese companies.

Polyvinyl Alcohol Manufacturing Process

Polyvinyl alcohol, the monomer of polyvinyl alcohol, cannot exist as a monomer because it is isomerized to the more stable acetaldehyde. Polyvinyl alcohol is therefore synthesized via polyvinyl acetate.

Industrially, vinyl acetate is synthesized from petroleum-derived ethylene, acetic acid, and oxygen. Palladium catalysts are used in this reaction.

Polyvinyl acetate is obtained by addition polymerization of the vinyl acetate. Polyvinyl alcohol is then synthesized by hydrolyzing polyvinyl acetate.

Properties of Polyvinyl Alcohol

Polyvinyl alcohol exists as a solid at room temperature and is soluble in warm water. This feature of solubility in warm water is unique among synthetic resins. This feature is due to the large amount of hydrophilic hydroxy groups (-OH groups) in the molecule.

This polyvinyl alcohol has properties, such as adhesion to hydrophilic surfaces, film formation, and viscosity.

It is also a stable polymer that does not easily change or deteriorate in various environments, making it an easy substance to handle over the long term. It has chemical resistance and dissolves only in special solvents such as dimethyl sulfoxide and water. It has almost no skin irritation, eye irritation, or skin sensitization, making it a safe substance for the human body.

Uses of Polyvinyl Alcohol

Polyvinyl alcohol is used in a wide variety of applications due to its properties.

Taking advantage of its water solubility and adhesive properties, it is used in cosmetics and as an adhesive or sizing agent.

When used in cosmetics, it is used for film formation and emulsion stabilization. By forming a film, liquid products such as foundation and mascara become a soft film and stay on the skin more easily.

When formulated as an adhesive, it is also used as a substance that serves as an adhesive as it is, and is often sold in the form of liquid glue. It is also used as a glue for the backs of stamps. It is also used as a synthetic laundry glue as a glue agent.

It is also used as a base material for polarizing plates used in liquid crystal displays. It is also used as a raw material for the synthetic fiber vinylon.

What Is Phenoxyethanol?

Phenoxyethanol (also known as ethylene glycol monophenyl ether, phenyl cellosolve) is an organic compound consisting of ethylene glycol and phenol ether bonded. It has a boiling point of 247°C, a melting point of -2°C, and a density of 1.10 g/cm3. It is characterized by a colorless viscous liquid at room temperature and a rose-like aroma.

It is easily soluble in water, alcohols, glycerin, and various other substances, making it easy to handle. It is also found in green tea and is a natural organic compound found in nature. It is a flammable substance and its flash point at normal pressure is 121 ºC.

Uses of Phenoxyethanol

Phenoxyethanol is often used as a preservative for various items because of its antibacterial properties.

In particular, it is often used in cosmetics, and with paraben-free products attracting attention, it is increasingly being added as a preservative that is safe and widely effective against many types of microorganisms. Cosmetics containing phenoxyethanol have a characteristic flowery fragrance even if no fragrance is used.

In addition to cosmetics, there are many other products that require antiseptic effects. It is used in a wide range of fields, including pharmaceuticals, dyes, inks, resins, lubricants, insect repellents, mold inhibitors in paints, additives in photographic films, and disinfectants.

Synthesis of Phenoxyethanol

It is synthesized by reacting phenol with oxirane (ethylene oxide), bromoethanol, or ethylene carbonate, resulting in hydroxyethylation.

What Is Trichlorobenzene?

Trichlorobenzene (TCB) is an organic compound with the molecular formula C6H3Cl3.

It is a derivative of benzene in which three of the six hydrogen atoms attached to the carbon atom of the benzene ring (tri) have been replaced with chlorine (chloro). There are three isomers with different positions of chlorine substitution: 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, and 1,3,5-trichlorobenzene.

Uses of Trichlorobenzene

Trichlorobenzene is mainly used as an intermediate raw material for dyes and pigments, pharmaceuticals and agrochemicals, and in the manufacturing of chemical products such as solvents, lubricants, and plastics.

Aromatic halogen compounds, such as trichlorobenzene, were once produced in large quantities as raw materials for chlorinated pesticides, primarily dichlorodiphenyl trichloroethane (DDT). Later, as the use of these pesticides was restricted, demand also declined. However, they are now used in herbicides and other agrochemicals.

In addition, organic compounds are highly soluble in aromatic halogens, and trichlorobenzene is widely used as a nonflammable solvent.

Properties of Trichlorobenzene

The physical properties differ depending on the isomer as follows:

1,2,3-trichlorobenzene is a white to slightly brown solid (melting point: 51-55°C, boiling point: about 220°C), 1,2,4-trichlorobenzene is a colorless liquid (melting point: 17°C, boiling point: 213°C), and 1,3,5-trichlorobenzene is a white solid (melting point: 63°C, boiling point: 208°C). The solubility of trichlorobenzene is about 0.5 mg/kg/kg.

Trichlorobenzene is insoluble in water, slightly soluble in alcohols, and readily soluble in benzene, ether, and acetone.

Trichlorobenzene is said to produce dioxins when heated at high temperatures, so care must be taken when handling it.

Other Information on Trichlorobenzene

1. Trichlorobenzene Production Process

Trichlorobenzene is obtained as a byproduct in the chlorination of benzene. When benzene is chlorinated, chlorobenzene with one chlorine substitution, dichlorobenzene with two chlorine substitutions, and trichlorobenzene with three chlorine substitutions are produced. Tetra-, tetra-, and higher order chlorides are also formed, which are separated to yield trichlorobenzene.

A method for producing 1,2,4-trichlorobenzene in high yield includes isomerization of o-dichlorobenzene (ortho-dichlorobenzene) and p-dichlorobenzene (para-dichlorobenzene) to obtain a mixture of m-chlorobenzene (meta-dichlorobenzene) of 50% or more, followed by chlorination. (meta-dichlorobenzene) mixture of 50% or more, followed by chlorination.

2. Handling and Storage of Trichlorobenzene

1,2,3-trichlorobenzene is classified as a newly designated chemical substance. There is a risk of eye irritation, digestive organ damage, and respiratory tract irritation. When burned, it decomposes to produce toxic and corrosive fumes such as hydrogen chloride. Containers should be sealed and stored in a cool, dry, well-ventilated place. Wear appropriate protective clothing, eye protection, respiratory protection, etc., and handle with care.

May cause mild skin irritation, respiratory tract irritation, drowsiness or dizziness.

Since the product decomposes when heated and generates carbon monoxide, carbon dioxide, hydrogen chloride, chlorine, etc. by combustion, keep the container closed and locked away from flames and hot surfaces in a cool, well-ventilated place. Furthermore, it reacts violently with oxidizing agents and acids, so it is important to keep it away from them. When handling, wear appropriate respiratory protection, protective gloves, protective clothing, face protection, etc., and take precautions.

What Is a Potassium Cyanide?

Potassium cyanide is an inorganic compound with the chemical formula KCN, also known as potassium cyanide or potassium cyanide. It is found as a colorless crystalline salt at room temperature and is soluble in water.

Although potassium cyanide has become synonymous with toxicity due to its strong toxicity, it is also an industrially important substance that is used in a wide range of fields, including organic synthesis, gold smelting, and electroplating.

Properties of Potassium Cyanide

Potassium cyanide is an ionic crystal composed of potassium and cyanide ions and is one of the typical alkali cyanide compounds. The carbon and nitrogen in the cyanide ion are linked by a triple bond.

Potassium cyanide is a white powdery crystal that is deliquescent, soluble in water, and strongly alkaline in aqueous solution. It is insoluble in organic solvents (methanol, ethanol, glycerin).

When it is tidied, it reacts with carbon dioxide in the air and releases hydrogen cyanide (HCN) while changing to potassium carbonate according to the following equation.
2 KCN + H2O + CO2 → K2CO3 + 2 HCN

Therefore, the product is odorless in the dry state, but in the air, it emits a characteristic almond odor due to hydrogen cyanide. Since the reaction is particularly likely to proceed under sunlight, the product should be stored away from sunlight to avoid exposure to air.

Production Process of Potassium Cyanide

Potassium cyanide is produced by treating hydrogen cyanide (HCN) with an aqueous solution of potassium hydroxide (KOH), followed by precipitation by evaporation of the solution in a vacuum.
HCN + KOH → KCN + H2O

Uses of Potassium Cyanide

Potassium cyanide is widely used in organic synthesis. Of particular importance is the reaction with alkyl halides to prepare nitriles (R-C≡N) according to the following formula:
R-X + KCN → R-CN + KX

Industrially, sodium cyanide (NaCN, sodium cyanide) is increasingly used in place of potassium cyanide.

It is also used as a photo-fixing agent. Potassium cyanide dissolves silver that is not insoluble in the developing solution. This makes the image clearer, more stable, and less sensitive to light. In modern times, sodium thiosulfate is increasingly used as a less toxic fixing agent.

It is also used as a smelting agent for gold, silver, and copper. Gold is leached from low-grade gold ores as a water-soluble salt according to the following formula:
4 Au (s) + 8 KCN (aq) + O2 (g) + 2 H2O (l) → 4 K[Au(CN)2] (aq) + 4 KOH (aq)

A similar process can also be used to leach as sodium gold cyanide NaAu(CN)2 using NaCN.

Potassium Cyanide Toxicity

When potassium cyanide enters the body orally, through the respiratory tract, or through the skin, cellular respiration is strongly inhibited and necrosis occurs. In the early stages of acute cyanide poisoning, the poisoned person’s complexion turns red because the tissues are unable to use oxygen from the blood. The brain is most affected, and death results from hypoxic encephalopathy. Symptoms of poisoning progress rapidly and will require immediate treatment. Symptoms usually appear within minutes of ingesting potassium cyanide. Respiratory distress, hypotension, loss of consciousness, and eventually brain death will occur.

The oral lethal dose of potassium cyanide is 200-300 mg for adults. The effects of sodium cyanide are similar to those of potassium cyanide.

If inhaled, fresh air should be immediately pumped into the lungs by artificial respiration. If ingested orally, the patient should vomit immediately (or be induced) and be artificially ventilated.