月: 2023年1月

What Is Magnesium Phosphate?

Magnesium phosphate is the general term for phosphates formed by magnesium and phosphoric acid. Magnesium phosphate is commonly known as primary, secondary, and tertiary magnesium phosphate, magnesium pyrophosphate, and magnesium metaphosphate. All magnesium phosphates are usually white powders in appearance and are stable compounds under normal handling. The most commonly used method of producing magnesium tertiary phosphate is to react to magnesium ammonium phosphate in an alkaline ammonia solution to obtain octahydrate.

Uses of Magnesium Phosphate

Magnesium phosphate has a wide variety of compositions, and various uses are known for magnesium phosphate depending on its composition. For example, ferrous magnesium phosphate is used as a raw material for ceramics and as a dental burial agent.

Diphosphoric magnesium phosphate is used in refractory binders and petrochemical catalysts, and tertiary magnesium phosphate is used in toothpaste stabilizers and phosphorus and magnesium supplements.

One particularly familiar use of magnesium phosphate, monophosphate, is widely used in dietary supplements that provide magnesium and as a pH adjuster in foods.

What Is Sodium Phosphate?

Sodium phosphate, predominantly known as trisodium phosphate (Na₃PO₄), is a compound also referred to as sodium orthophosphate. It appears as a white, odorless crystal with a molecular weight of 163.94 and a CAS number of 7601-54-9. Disodium hydrogen phosphate (Na₂HPO₄) is another form often called sodium phosphate in pharmaceutical and industrial contexts.

Uses of Sodium Phosphate

1. Food Industry

Used as a binding agent in meats and as a pH adjuster and brine additive, enhancing texture and flavor.

2. Industrial Applications

Employed in photography, paper manufacturing, tanning, dyeing, and as an ingredient in pharmaceuticals, detergents, and plant disease disinfectants.

Properties of Sodium Phosphate

Sodium phosphate is highly soluble in water, with a solubility of 14.5g per 100g water at 25°C, and forms strongly alkaline solutions. It has a density of 2.5 g/cm³ and a high melting point of 1340°C. Upon heating, it decomposes, emitting toxic fumes and is insoluble in ethanol.

Types of Sodium Phosphate

It exists in various forms, including anhydrous, monohydrate, hexahydrate, heptahydrate, decahydrate, and dodecahydrate, with the anhydrous, hexahydrate, and dodecahydrate forms being the most commercially prevalent.

Other Information on Sodium Phosphate

1. Synthesis of Sodium Phosphate

Sodium phosphate can be synthesized from the reaction of phosphoric acid with sodium hydroxide, yielding various hydrates under different conditions. It also reacts with hydrogen chloride and perchloric acid, forming by-products like sodium chloride and sodium perchlorate.

2. Neutralization Titration and Buffering of Aqueous Phosphoric Acid Solutions

The neutralization titration of sodium phosphate with sodium hydroxide involves a three-step reaction process, showcasing its buffering capabilities in solutions above pH 11.

What Is Potassium Phosphate?

Potassium phosphate refers to a group of inorganic compounds consisting of potassium and phosphate ions.

These include potassium dihydrogen phosphate (KH₂PO₄), dipotassium hydrogen phosphate (K₂HPO₄), and tripotassium phosphate (K₃PO₄), collectively known as potassium phosphates.

Uses of Potassium Phosphate

Potassium phosphates are extensively used as food additives, serving as binding agents in processed meats and fish pastes, emulsifiers in processed cheese, and ingredients in brine for Chinese noodles.

Furthermore, potassium dihydrogen phosphate finds applications in the brewing industry as a culture medium, pH adjuster, de-ironing agent, fermentation accelerator, buffer, and fertilizer. It also has a broad range of industrial uses, including in microbial culture substrates, processed food additives, petrochemical catalysts, antifreeze blending agents, and clarifying agents.

Properties of Potassium Phosphate

1. Tripotassium Phosphate

Tripotassium phosphate (K₃PO₄), with CAS number 7778-53-2, is a hygroscopic white powder that is insoluble in alcohol but has a water solubility of 90 g/100 mL at 20°C. It forms an alkaline solution with a pH of 11.5 to 12.5.

2. Dipotassium Hydrogen Phosphate

Dipotassium hydrogen phosphate (K₂HPO₄), CAS number 7758-11-4, is a deliquescent colorless crystal that decomposes at 465°C. Its aqueous solution is slightly alkaline, and it is readily soluble in water with a solubility of 167 g/100 mL at 20°C.

3. Potassium Dihydrogen Phosphate

Potassium dihydrogen phosphate (KH₂PO₄), CAS number 7778-77-0, is a white crystalline powder that decomposes at 400°C. It is insoluble in alcohol, with a water solubility of 22 g/100 mL at 25°C.

Types of Potassium Phosphate

These potassium phosphates are sold for various applications, including as reagent products for research and development, food additives, and industrial raw materials.

1. Reagent Products for Research and Development

Available in a range of sizes and grades, potassium phosphates are tailored for specific research needs, from small laboratory quantities to bulk industrial sizes. Solutions and hydrate forms are also available for specialized applications.

2. Industrial Products

For industrial use, potassium phosphates are packaged in varying capacities, catering to a wide array of applications beyond food additives, including technological and manufacturing processes.

Additionally, potassium polyphosphate (KPO₃)_x is utilized in food processing and as a meat binder, demonstrating the versatility of potassium phosphates in various applications.

What Is Ammonium Phosphate?

Ammonium phosphate is an inorganic compound resulting from the acid-base reaction between phosphoric acid and ammonia.

It exists in three forms: monoammonium phosphate (NH₄H₂PO₄), diammonium phosphate (NH₄)₂HPO₄, and triammonium phosphate (NH₄)₃PO₄.

Uses of Ammonium Phosphate

Monoammonium and diammonium phosphate are the two types commonly used in the industry, sharing many applications despite their differing compositions.

1. Monoammonium Phosphate

It is utilized as an extinguishing agent in ABC fire extinguishers, which are versatile in putting out various types of fires.

2. Diammonium Phosphate

Often referred to as ammonium phosphate, it is extensively employed as a chemical fertilizer. Its industrial applications include uses as a metal surface treatment agent, organic synthesis catalyst, wastewater treatment agent, dyeing aid, and enamel glaze.

In pharmaceutical and food industries, it serves as a reagent, bio-agent, brewing additive, expansion agent, emulsifier, culture medium, pH adjuster in cosmetics, buffering agent, and oral care product.

Properties of Ammonium Phosphate

1. Monoammonium Phosphate (NH₄H₂PO₄)

A colorless or white crystalline powder, it has a molecular weight of 115.03, a specific gravity of 1.803, and melts at 190°C. It is air-stable, highly soluble in water with a slightly acidic solution pH of 4.0 to 5.0, and exhibits buffering capabilities. It forms insoluble salts with soluble alkaline earth metals and is virtually insoluble in ethanol. Decomposition occurs above 216°C, releasing ammonia.

2. Diammonium Phosphate (NH₄)₂HPO₄

This colorless or white crystalline powder, with a molecular weight of 132.06 and specific gravity of 1.619, melts at 190°C and is relatively stable in air. It dissolves well in water, producing a slightly alkaline solution with a pH of 7.6 to 8.4 and acts as a buffer. Like the monoammonium form, it reacts with soluble alkaline earth metals to form insoluble salts and is nearly insoluble in ethanol. It decomposes above 155°C to produce ammonia.

3. Triammonium Phosphate (NH₄)₃PO₄・3H₂O

Available as a hydrate, this white crystalline powder has a molecular weight of 203.13. It is air-unstable, readily producing ammonia and converting to diammonium phosphate, hence possessing a strong ammonium phosphate odor. It dissolves well in water, resulting in an alkaline solution with a pH of about 10, and is almost insoluble in ethanol.

Other Information on Ammonium Phosphate

How Ammonium Phosphate Is Produced

Ammonium phosphate is synthesized by reacting phosphoric acid with ammonia in aqueous solution. Adjusting the ratio of phosphoric acid to ammonia allows for the production of its three forms:

• H₃PO₄ + NH₃ → NH₄H₂PO₄
• H₃PO₄ + 2NH₃ → (NH₄)₂HPO₄
• H₃PO₄ + 3NH₃ → (NH₄)₃PO₄

Phosphoric acid can be produced by either the wet or dry process. The wet process involves decomposing phosphate rock with sulfuric acid, while the dry process involves thermal decomposition in an electric furnace. While the dry process yields higher purity phosphoric acid and is more energy-intensive and costly, the wet process is typically used for fertilizer production where high purity is not essential. However, advancements in refining technology for the wet process have improved the quality of phosphoric acid for industrial and food applications.

What Is Aluminum Phosphate?

Aluminum phosphate is an inorganic compound consisting of aluminum and phosphate ions.

It is denoted by the chemical formula AlPO₄ and appears as a white powdery solid under standard temperature and pressure. Berlinite, a naturally occurring form of aluminum phosphate, is considered an ore.

Aluminum phosphate is produced by combining aqueous solutions of aluminum ions and phosphate ions, which leads to crystallization. Upon heating, the compound decomposes into aluminum oxide and diphosphorus pentoxide.

Uses of Aluminum Phosphate

1. Alumina Ceramics

Aluminum phosphate serves as a raw material for alumina ceramics, known for their exceptional hardness, heat resistance, corrosion resistance, and thermal conductivity, while maintaining low electrical conductivity.

Its low electrical conductivity makes it ideal for use in various mechanical parts, especially electrical insulating components.

2. Cement

In dentistry, aluminum phosphate contributes to the formulation of dental cements, enhancing their resistance to acids, bases, pressure, and tension.

3. Binder

Acid aluminum phosphate, derived from phosphoric acid and aluminum hydroxide, is used in refractory binders and foundry sand binders.

This water-soluble acidic phosphate, with the formula Al₂O₃-3P₂O₅-6H₂O, hardens and binds through condensation by dehydration and crystal transition when heated to high temperatures. It functions as a binder, metal surface treatment agent, and fire retardant.

4. Other Uses

Aluminum phosphate is utilized as an adsorbent, in firebricks, refractory concrete, non-alkali glass, the ceramic industry, and as a special coating agent. It also finds applications in the chemical industry, particularly in the production of acetic anhydride at high temperatures.

Properties of Aluminum Phosphate

Aluminum phosphate is odorless and has a molecular weight of 121.95 g/mol and a CAS number of 7784-30-7.

Its melting point is not defined above 450°C, and it has no specific boiling or flash point data, aligning with its non-flammable classification under GHS. The density is 2.56 g/mL at 25°C, and it has a solubility in water of 6.92 g/L at 20°C. It is chemically stable under normal atmospheric conditions, though contact with strong bases should be avoided.

Other Information on Aluminum Phosphate

1. Handling Instructions

Despite not being classified as hazardous under GHS criteria, handling should involve protective eyewear and safety gloves, especially to mitigate dust exposure. While not inherently flammable, precautions against dust explosions require adequate ventilation. Always wash hands after handling and maintain cleanliness to prevent product dissemination outside the work area.

2. First Aid Measures

In case of exposure, despite its non-hazardous classification, ensure fresh air for inhalation incidents, water rinsing for skin contact, abundant water flushing for eye exposure, and water intake if ingested, consulting a physician if discomfort persists.

3. Fire Precautions

Extinguish fires using water, foam, or carbon dioxide powder, selecting the extinguishing agent based on the environment and conditions, while wearing self-contained breathing apparatus to avoid inhaling potentially toxic combustion products.

4. Storage

Ensure storage in a dry, tightly sealed environment away from strong bases, adhering to proper disposal protocols for industrial waste in compliance with laws, regulations, and local ordinances.

What Is Phosphoric Acid?

Phosphoric acid, alongside nitrogen and potassium, is one of the three primary elements of fertilizer and an oxoacid of phosphorus.

Also known as orthophosphoric acid, it promotes flowering and fruiting in plants and is a crucial component of DNA and RNA, the genetic material, and cell membranes in living organisms. Phosphoric acid is essential for life.

As a natural resource, phosphorus is found as phosphate ore, and its depletion is concerning. Phosphoric acid is industrially produced through two methods: dry and wet.

Uses of Phosphoric Acid

Phosphoric acid is widely used in industry as a raw material for various phosphates, chemical polishing agents for aluminum, rust inhibitors for metals, metal cleaning agents, can cleaners, refractory auxiliaries, paint preparation agents, activated sludge processes, phosphate fertilizers, and reagents.

In food applications, it serves as an acidifier for beverages, a pH adjuster in brewing, and a raw material for phosphoric acid additives in juices, colas, and other food products.

It is also utilized as a raw material for dyeing auxiliaries, petrochemical catalysts, and pharmaceutical additives.

Properties of Phosphoric Acid

Phosphoric acid has a melting point of 42.35°C and a boiling point of 407°C. When melted, it appears as a clear, colorless liquid.

It is soluble in water, alcohol, and ether. Liquid anhydrous phosphoric acid is a strong acid and a high conductor of electricity.

Structure of Phosphoric Acid

Figure 1. Structure of Phosphoric Acid

The chemical formula of phosphoric acid is H₃PO₄. Its molar mass is 98.00 g/mol, and its density at 25°C is 1.892. Pure phosphoric acid forms unstable crystals of the orthorhombic system.

Phosphoric acid ions adopt a tetrahedral structure. The bond distance between phosphorus and oxygen (P-O) in aluminum phosphoric acid crystals is 152 pm.

Other Information on Phosphoric Acid

1. Synthesis of Phosphoric Acid

Burning phosphorus produces diphosphorus pentoxide, which, when dissolved in a dilute aqueous solution of phosphoric acid, yields pure phosphoric acid. This thermal synthesis method is environmentally friendly, although impurities in the mined phosphorus must be removed.

Phosphoric acid can also be obtained by reacting approximately 35% sulfuric acid with phosphate ore. This wet synthesis method can be purified through filtration, but may contain impurities such as hydrofluoric acid, resulting in lower purity than the thermal synthesis method.

2. Structure of Phosphoric Acid Ion

Figure 2. Structure of Phosphoric Acid Ion

Phosphoric acid, a trivalent acid, ionizes in aqueous solution, releasing three hydrogen ions. The ionization stages produce dihydrogen phosphate (H₂PO₄^–), hydrogen phosphate (HPO₄^2-), and phosphate (PO₄^3-) ions.

The pK_a values at 25°C are pK_a1 = 2.12, pK_a2 = 7.21, and pK_a3 = 12.67, respectively.

3. Dehydration Reaction of Phosphoric Acid

Figure 3. Structure of Condensed Phosphoric Acid

Upon heating, phosphoric acid undergoes a dehydration reaction. At 150°C, it becomes anhydrous, and at 200°C, two molecules react to form pyrophosphoric acid. Higher temperatures lead to the formation of meta-phosphoric acid, a condensed compound, when one water molecule per phosphoric acid unit is desorbed. Diphosphorus pentoxide, produced by further dehydration, reacts violently with water and is used as a drying agent.

4. Phosphoric Acid and Health

Phosphorus, found in foods of biological origin such as vegetables and meat, is used as an acidity additive in foods and beverages. It is a necessary mineral for the human body, with recommended daily amounts set by health authorities.

What Is Phosphomolybdic Acid?

Phosphomolybdic acid (PMA), a compound of phosphorus, molybdenum, and oxygen atoms, is represented by the chemical formula H₃[PMo₁₂O₄₀], also known as molybdophosphoric acid. This yellow crystalline substance, notable for its solubility in water and ethanol, exhibits remarkable stability in acidic environments.

It is classified under various safety and environmental regulations due to its hazardous nature, necessitating careful handling.

Uses of Phosphomolybdic Acid

1. Organic Chemistry

PMA serves as a catalyst in esterification, hydration, and oxidation reactions within organic chemistry. It also acts as a staining agent in thin layer chromatography (TLC) for detecting organic compounds.

2. Analytical Chemistry

As a detection reagent, PMA reacts with alkaloids to form precipitates and is employed as the Sonnenschein reagent in a 1% ethanol solution. Its ability to precipitate with ammonia, amines, and proteins makes it a versatile agent, also used alongside phosphotungstic acid for phenol detection. In protein quantification, via the Lowry method, it reacts with certain amino acids to produce a blue coloration.

Properties of Phosphomolybdic Acid

This yellow crystalline acid is soluble in water and polar organic solvents, with a molecular weight of 1825.25. It acts as a strong acid and potent oxidizer, reduced by unsaturated compounds to form molybdenum blue in staining applications for TLC.

Structure of Phosphomolybdic Acid

As a polyoxometalate, its structure features a central molybdenum atom surrounded by oxygen atoms, forming a Keggin structure with a coordination of four oxygen atoms to each molybdenum.

Other Information on Phosphomolybdic Acid

How Phosphomolybdic Acid is Produced

Commonly produced through the reaction of molybdenum (IV) oxide with phosphoric acid in an aqueous solution, this process is enhanced by donor molecules like tributylamine to suppress byproducts and improve yield, using diethyl ether for extraction and purification.

While older methods involved acidifying sodium phosphomolybdic acid and extracting with ether, the complexity of sodium removal has made such methods less favored in current practices.

What Is Phosphotungstic Acid?

Phosphotungstic acid, an inorganic heteropoly acid of tungsten, is known for its various aliases including tungstophosphoric acid and 12-tungstophosphoric acid, with abbreviations TPA and PTA. A notable example is H₃PW₁₂O₄₀.

Uses of Phosphotungstic Acid

1. Synthetic Reaction Catalysts

As a catalyst, phosphotungstic acid facilitates numerous organic synthetic reactions, demonstrating thermal stability up to 400°C. It is applicable both as a homogeneous catalyst in solution for hydration, ester exchange, and polymerization, and as a heterogeneous catalyst on substrates like alumina or silica.

• Homogeneous catalysis in 2-propanol hydrolysis and the Prins reaction.
• Heterogeneous catalysis in converting 2-propanol to propene and methanol to hydrocarbons.

The Prins reaction exemplifies its role as an acid catalyst, producing homoallylic alcohols from aldehydes and allyl compounds.

2. Staining Agent

It is employed as a staining agent for phosphoric acid colorimetric determination and for cell negative staining in transmission electron microscopy.

3. Protein Precipitant

Phosphotungstic acid effectively precipitates polar proteins, targeting guanidino, epsilon-amino, and imidazole groups.

Properties of Phosphotungstic Acid

Its chemical formula, molecular weight, and CAS number are H₃O₄₀PW₁₂, 2880.2, and 1343-93-7, respectively. The 24-hydrate form melts at 89°C, appearing as a white or yellow-green crystalline powder, soluble in water, ethanol, and diethyl ether, exhibiting high acid strength in concentrated solutions.

The anion structure exhibits tetrahedral symmetry, with 12 tungsten atoms forming a cage around a centrally placed phosphorus atom.

Types of Phosphotungstic Acid

Typically sold as a hydrate, its formula is H₃O₄₀PW₁₂・nH₂O, with the CAS number 12501-23-4, predominantly isolated as 24-hydrate but also available in 6-hydrate.

Other Information on Phosphotungstic Acid

1. Production Process of Phosphotungstic Acid

It is synthesized by reacting sodium tungstate dihydrate with phosphoric acid, acidified using hydrochloric acid.

2. Regulatory Information

• Identified in Industrial Safety and Health Law as hazardous, with specific regulations for transport and storage.
• Classified as a corrosive substance under maritime and aviation regulations.

3. Precautions for Handling and Storage

Handling requires protective gear, with fire safety precautions due to potential toxic gas release. Store as a hydrate in sealed containers, refrigerated, away from sunlight, in a locked area.

What Is D-Limonene?

D-limonene, a monocyclic monoterpene, is a key component of essential oils found in citrus peels, characterized by its optically active forms, including D- and L-limonene. The D-form is particularly noted for its lemony fragrance, whereas dipentene refers to the racemic mixture of these isomers. D-limonene predominates in oils from orange peel, lemon, and bergamot, L-limonene in pine needle and huckleberry oils, and dipentene in camphor and turpentine oils.

Physicochemical Properties of D-Limonene

As a cyclic terpene, D-limonene is renowned for its distinct citrus aroma, found primarily in citrus peel. Its properties make it an effective solvent in various applications, capable of dissolving fats and oils.

1. Name
English Name: Limonene
IUPAC Name: 1-methyl-4-(1-methylethenyl)-cyclohexene

2. Molecular Formula
C₁₀H₁₆

3. Molecular Weight
136.23 g/mol

4. Melting Point
-74.35°C

5. Solvent Solubility
Insoluble in water, but soluble in alcohols

Uses of D-Limonene

D-limonene finds extensive use as a flavoring agent in food, beverages, and bath products, and as a solvent in industrial applications due to its unique aroma and solvent properties.

1. Use as a Flavoring Agent

It is a popular flavoring agent in citrus-flavored foods and beverages, and is used in soaps, detergents, cosmetics, and air fresheners due to its fragrance. Its effectiveness in dissolving oily substances also makes it a valuable ingredient in hand soaps and kitchen detergents.

2. Use as a Synthetic Chemical Raw Material

Its ability to dissolve oils has led to its widespread use as a solvent in paints, printing inks, and other industrial applications.

3. Structural Similarity With Styrene and Use as a Styrofoam Recovery Agent

Due to its structural similarity to styrene, D-limonene can dissolve styrene foam, making it a useful recycling agent for styrofoam.

Structure of D-Limonene

D-limonene is a chiral molecule with two enantiomers, existing primarily in citrus peels. Its molecular formula is C₁₀H₁₆. The D-enantiomer is responsible for the strong citrus odor, whereas the racemic form is known as dipentene.

It features two unconjugated C=C double bonds, contributing to its reactivity and susceptibility to oxidation.

Other Information on D-Limonene

How D-Limonene Is Produced

D-limonene is naturally extracted from citrus peels through mechanical squeezing, steam distillation, or chemical synthesis, yielding an oil rich in D-limonene along with other components such as carboxylic acids, aldehydes, and ketones.

(1) Extraction
The essential oil is extracted from citrus peels through mechanical squeezing and distillation.

(2) Steam Distillation
This process involves steam distilling the citrus peel, then cooling the vapor to separate the oil.

(3) Chemical Synthesis
Chemical synthesis methods include the dehydration of ethanoic acid, hydrohalogenation of isoprene, and hydrolysis of β-pinene.

What Is Lanolin Alcohol?

Lanolin alcohol is derived from lanolin, a natural oil or fat extracted from sheep’s wool. Through the hydrolysis of lanolin, a mixture of alcohols known as lanolin alcohol is obtained. This mixture contains several types of alcohol, and the composition varies depending on the processing method. Different manufacturers produce lanolin alcohol with varying compositions, leading to names like “lanolin alcohol A” and “lanolin alcohol CSY.”

Uses of Lanolin Alcohol

Rich in cholesterol, lanolin alcohol is known for its excellent water retention and emulsifying properties. It is a natural alcohol that is generally non-irritating to the skin and eyes, making it safe for use in human body applications. Lanolin alcohol is commonly used as an ingredient in various cosmetic products, including shampoos and body creams.

Due to its emollient properties, lanolin alcohol is often added to creams and other cosmetic formulations to enhance their texture and feel. It is also used in emulsified liquid products to aid in emulsification and improve fluidity, contributing to the overall effectiveness and user experience of these products.