月: 2023年4月

What Is Hydroxybutyric Acid?

Hydroxybutyric acid is a derivative of a 4-carbon carboxylic acid with a hydroxy group. It has three linear isomers: α-hydroxybutyric acid (2-hydroxybutyric acid), β-hydroxybutyric acid (3-hydroxybutyric acid), and γ-hydroxybutyric acid (4-hydroxybutyric acid), each located at different positions on the carbon chain. All these isomers share the molecular formula C4H8O3 and have a molecular weight of 104.105.

Uses of Hydroxybutyric Acid

1. Alpha-Hydroxybutyric Acid

α-Hydroxybutyric acid serves as a biomarker for diagnosing colorectal cancer and type 2 diabetes. Elevated serum levels of this acid indicate impaired glucose tolerance.

2. Beta-Hydroxybutyric Acid

β-Hydroxybutyric acid is a precursor for polyhydroxybutyric acid (PHB), a biodegradable plastic material. It is derived from various microorganisms and is valuable in producing environmentally friendly plastics.

3. Gamma-Hydroxybutyric Acid

γ-Hydroxybutyric acid is used in treating narcolepsy and alcoholism and has been approved for therapeutic use in many European countries. Initially developed as an anesthetic, it is now regulated due to its potential for misuse.

Properties of Hydroxybutyric Acid

1. Alpha-Hydroxybutyric Acid

α-Hydroxybutyric acid, a colorless solid with a melting point between 50-54 °C, is an intermediate in amino acid metabolism. It is linked to oxidative stress and produced in tissues, mainly in the liver, through the metabolism of threonine or biosynthesis of glutathione.

Oxidative stress increases glutathione biosynthesis in the liver, leading to a reduction in cysteine, the precursor of glutathione, and the byproduct α-hydroxybutyric acid.

2. Beta-Hydroxybutyric Acid

β-Hydroxybutyric acid, like other ketone bodies such as acetoacetic acid and acetone, serves as an energy source for the brain and muscles during fasting or in diabetic ketosis.

It is also the monomer for polyhydroxybutyrate, a type of biodegradable polyester.

3. Gamma-Hydroxybutyric Acid

Gamma-hydroxybutyric acid acts as a central nervous system depressant and can cause sleep and sex-enhancing effects. However, its overdose may lead to seizures and disorientation.

Structure of Hydroxybutyric Acid

1. Alpha-Hydroxybutyric Acid

α-Hydroxybutyric acid has a hydroxy group on the α-carbon adjacent to the carbonyl group. It has a chiral carbon atom, existing in two stereoisomers: D- and L-forms.

2. Beta-Hydroxybutyric Acid

β-Hydroxybutyric acid, often mistaken as a ketone, actually lacks a ketone group. It has a hydroxy group on the β-carbon. It also has chiral carbon and exists as D- and L-forms, but physiologically, only the D-form is present.

3. Gamma-Hydroxybutyric Acid

γ-Hydroxybutyric acid has a hydroxy group on the γ-carbon from the carbonyl group. It is naturally found in foods like wine, beef, and citrus fruits.

Other Information on Hydroxybutyric Acid

1. Branched Structure of Hydroxybutyric Acid Isomers

Besides linear isomers, hydroxybutyric acid also has branched isomers, such as 2-hydroxyisobutyric acid and 3-hydroxyisobutyric acid.

2. Characteristics of 2-Hydroxyisobutyric Acid

2-Hydroxyisobutyric acid is formed from the hydrolysis of 3-hydroxybutyryl CoA to 2-hydroxyisobutyryl CoA. It’s a precursor to ethyl methacrylate, an important industrial monomer, produced by dehydrating its ethyl ester with phosphorus pentachloride.

3. Characteristics of 3-Hydroxyisobutyric Acid

3-Hydroxyisobutyric acid, a metabolic intermediate of valine, has two optical isomers: D- and L-3-hydroxyisobutyric acid due to its asymmetric carbon atom.

What Are Hydroxyradicals?

Hydroxyradicals, represented by the chemical formula -OH, are radicals corresponding to hydroxy groups. The free group OH and the atomic group OH are referred to as hydroxyl radicals. The cation OH+ is known as the hydroxylium ion, while the anion OH- is termed the hydroxide ion. In the context of a ligand, it is represented by hydroxide or hydroxo. The -OH substituent in a compound is called a hydroxy group.

Hydroxyradicals are the three-electron-reduced form of oxygen, being the most reactive and most oxidizing among reactive oxygen species. They can react with various substances, including carbohydrates, proteins, and lipids. Due to their extremely high reactivity, hydroxyradicals have a very short lifespan in normal environmental conditions and disappear rapidly after formation.

Uses of Hydroxyradicals

Hydroxyl radicals are produced during certain chemical reactions, causing oxidation and then quickly disappearing.

In vitro, they can be generated through ultraviolet irradiation of hydrogen peroxide or by the Fenton reaction, which involves the catalytic reaction of hydrogen peroxide with a divalent iron compound under acidic conditions.

In vivo, hydroxyl radicals are produced inside mitochondria and cells, leading to mitochondrial dysfunction and cell damage. They are implicated in the development of diseases like cancer, Parkinson’s disease, and dementia. Antioxidants known to neutralize hydroxyl radicals in the body include hydrogen, β-carotene, α-carotene, vitamin E, uric acid, linoleic acid, cysteine, flavonoids, and glutathione.

What Is Hydroxyproline?

Hydroxyproline, abbreviated as Hyp, is a secondary cyclic amino acid derived from the hydroxylation of proline in the presence of vitamin C. Recognized as a key component of collagen, hydroxyproline exists as white, hexagonal crystals, readily soluble in water and marginally in ethanol.

Uses of Hydroxyproline

1. Cosmetic Industry

Due to its role in collagen synthesis and skin cell proliferation, hydroxyproline is valued in cosmetics for enhancing skin elasticity, firmness, and moisture, thus counteracting aging signs. However, its topical application is preferred as oral ingestion does not directly benefit skin collagen.

2. Medical Applications

As a collagen marker, hydroxyproline aids in diagnosing conditions related to collagen degradation, including bone diseases, liver fibrosis, and cancer metastases through collagen content measurement in various tissues.

3. Dietary Uses

Found abundantly in gelatin and meats, hydroxyproline supplements aim to support dietary needs, particularly for skin, tendon, and bone health.

Chemical and Physical Properties

With the formula C₅H₉NO₃ and a molecular weight of 131.13, hydroxyproline is a white powder that dissolves in water but not in ethanol or ether. It’s chemically stable, yet sensitive to high temperatures and direct sunlight.

Other Information on Hydroxyproline

1. Safety Measures

Lacking specific GHS hazard classifications, hydroxyproline is generally considered safe with recommended storage in cool, well-ventilated areas away from oxidizers and sunlight.

2. Proper Handling

Precautions include using dust-proof masks and protective gear, establishing local exhaust and emergency wash facilities, and maintaining hygiene post-handling.

3. Role in Collagen Structure

Hydroxyproline, synthesized via proline hydroxylation, is crucial for collagen’s triple helix stability, relying on vitamin C for its formation. A deficiency in vitamin C can compromise collagen stability, leading to scurvy.

What Is Hydroxide?

Hydroxide is a general term for compounds containing the hydroxide ion, OH-. Another term for hydroxide is orate. The hydroxylium ion is referred to as OH+ (cation), while the hydroxide ion is OH- (anion).

The term “hydroxyl radicals” refers to the free group -OH and the atomic group OH. The substituent -OH in a compound is known as a hydroxy group. To denote the presence of the -OH group as a prefix in a compound, the term “hydroxy” is used, as in hydroxyacetic acid. When indicating the -OH group as a suffix, the addition of “-ol” is used, as seen in ethanol.

Uses of Hydroxide

Potassium hydroxide is primarily utilized as a base, preparing stronger basic solutions than sodium hydroxide and being used to titrate the saponification value of fats and oils. It’s also a raw material in commercial cleaning agents, pipe-clogging cleaners, and liquid soap for industrial and general use.

In industrial applications, hydroxide is extensively used, including as a catalyst in tetramethylammonium hydroxide. Its specific uses encompass catalysts for polymerization and condensation reactions, pretreatment agents for gas chromatography, chemicals in photography and printing, photoresist developer solutions, and alkaline electrolytes for rechargeable batteries.

Tricyclohexyltin hydroxide is employed as an insecticide and repellent (e.g., for mites), an insect sterilizer, and an antifungal agent.

What Is Histamine?

Figure 1. Histamine basic information

Histamine is an active amine with a molecular formula of C5H9N3 and a molecular weight of 111.14.

It was discovered by Henry Hallett Dale and Patrick Playfair Laidlaw in 1910 as a hypotensive substance in wheat extract.

Histamine is synthesized in the body in addition to being directly ingested through food. Symptoms of histamine food poisoning are similar to food allergies caused by an abnormal immune response, but the mechanisms differ.

Uses of Histamine

Histamine is used to test gastric juice secretory function and chromophilic cell tumors. As a pharmacological agent, it can cause smooth muscle contraction, rapid hypotension due to dilation of small arteries, inflammation-related redness, edema from increased capillary permeability, and enhanced secretory gland function.

Properties of Histamine

Histamine has a melting point of 181.4-183.2 °F (83-84 °C) and a boiling point of 716.5 °F (380.29 °C). Its hydrochloride and phosphate salts are hygroscopic white crystals, soluble in water and ethanol but not in ether.

The pKa of histamine’s imidazole ring nitrogen atom is 6.04, and that of the aliphatic amino group is 9.75. Under physiological conditions, the aliphatic amino group is protonated, while the imidazole ring nitrogen atom is not. Therefore, histamine typically exists as a monovalent cation in human blood, which has a pH of 7.35-7.45.

Structure of Histamine

Figure 2. Structure of histamine

In an aqueous solution, histamine’s imidazole ring exists in two tautomeric forms, with one nitrogen atom protonated. The nitrogen atom farther from the side chain is denoted τ, and the one closer is π. Nτ-H-histamine is more stable than Nπ-H-histamine.

Histamine, also known as β-imidazolethylamine, is a monoamine neurotransmitter, a category including adrenaline, noradrenaline, dopamine, and serotonin.

Other Information on Histamine

1. Synthesis of Histamine

Figure 3. Histamine synthesis

Histamine can be synthesized by cyclizing 1,4-diamidino-2-butanone with potassium thiocyanide, followed by treatment with iron(III) chloride.

In the body, histamine is produced by enzymatic action on histidine, an amino acid found in food. It is stored primarily in mast cells and released in response to stimuli, leading to allergic reactions. Histamine neurons, located in the hypothalamus-mammillary body, act as neurotransmitters affecting sleep, wakefulness, and feeding.

2. Histamine Toxicity

Histamine poisoning is often caused by bacterial synthesis in foods. It can lead to septic shock symptoms after platelet transfusion and is commonly found in aged cheese, shiitake mushrooms, fermented foods, fish sauce, wine, and fish, especially red and blue varieties.

High histamine concentrations in foods can cause allergy-like symptoms, such as flushing, headache, and hives, usually resolving within a day. Histamines are not destroyed by cooking and are hard to detect by taste or smell. Preventive measures include temperature control and freshness checks during storage. If irritation is felt on the lips or tongue from high-histamine foods, it is advisable to spit it out.

What Is Nitro?

Nitro refers to a functional group commonly found in organic compounds. This group is also known as the nitro group and broadly includes nitrate esters (R-ON2). Organic compounds like nitroglycerin (specific formula: C3H5(ONO2)3) and nitrocellulose fall under nitrate esters. Trinitrotoluene (TNT, C6H2CH3(ON2)3), an explosive material, is synthesized by substituting three hydrogen atoms in the phenyl ring of toluene (C6H5CH3).

Uses of Nitro

Nitro compounds have several significant applications, particularly in the fields of explosives and pharmaceuticals. In medical applications, nitro compounds like nitroglycerin are used due to their vasorelaxant effects, which widen blood vessels and are effective in treating angina attacks. Nitroglycerin is commonly administered as a sublingual tablet for angina pectoris.

In the realm of explosives, nitro compounds play a crucial role. Alfred Nobel, the founder of the Nobel Prize, notably invented dynamite, a safer explosive utilizing nitro compounds. Additionally, nitro compounds are used in the manufacture of smokeless gunpowder.

What Is Trichlorosilane?

Trichlorosilane, with the formula HCl₃Si, is an inorganic compound known also as silicon trichloride or TCS. It serves as a precursor to high-purity polycrystalline silicon (polysilicon), vital for semiconductor manufacturing.

Due to its hazardous and flammable nature, trichlorosilane is strictly regulated under various laws, highlighting its combustibility and the need to handle it away from water.

Applications of Trichlorosilane

Its primary uses span both inorganic and organic chemistry sectors. In inorganic chemistry, it’s crucial for producing semiconductor-grade silicon, while in organic chemistry, it’s used to manufacture silane coupling agents, silicon resins, and as a versatile reagent in the synthesis of organosilicon compounds and as a reducing agent.

Physical Properties

As a clear, colorless liquid, trichlorosilane has a pungent odor, a low boiling point of 31.8°C, and exhibits extreme flammability, reacting vigorously with air.

Chemical Structure

The molecule is tetrahedral, consisting of a silicon atom centrally bonded to one hydrogen and three chlorine atoms. This structure contributes to its reactivity and utility in various chemical processes.

Detailed Insights

1. Production Techniques

Industrially, trichlorosilane is synthesized by reacting silicon powder with hydrogen chloride gas at high temperatures. This process also generates hydrogen gas and has a high yield, though it produces several by-products that are separated through distillation.

2. Chemical Reactions

Trichlorosilane is highly reactive with moisture, releasing hydrogen chloride gas and forming silica upon exposure to air. It facilitates transformations in organic synthesis, such as converting benzoic acid to toluene derivatives, and is pivotal in producing various organosilicon compounds through hydrosilylation.

3. Use in Material Science

The organosilicon compounds derived from trichlorosilane find extensive applications in creating self-assembled monolayers, enhancing surface properties for MEMS coatings, nanoimprint lithography, and injection molding, due to their ability to reduce surface energy and adhesion.

What Is Triazole?

Triazole is a five-membered ring compound with three nitrogen atoms and two carbon atoms, having the chemical formula C2H3N3. There are two isomeric forms: 1,2,3-triazole and 1,2,4-triazole, both exhibiting aromatic properties.

Triazole is used in pharmaceuticals, with each isomer being a component of different drugs.

Uses of Triazole

1,2,3-Triazole is an important component in the antibiotic tazobactam piperacillin for injection, used to treat conditions like complicated cystitis, pyelonephritis, pneumonia, peritonitis, sepsis, and febrile neutropenia.

Properties of Triazole

1,2,3-Triazole is crystalline, sweet-tasting, and has a melting point of 23-25 °C and a boiling point of 203 °C. It is soluble in water and ethanol. At temperatures above 500 °C in a vacuum, it decomposes, releasing nitrogen to form aziridine.

Structure of Triazole

Triazole forms a five-membered ring with two carbon and three nitrogen atoms. 1,2,3-Triazole, with adjacent nitrogen atoms, is exceptionally stable. In aqueous solution, it forms tautomers such as 2H-1,2,3-triazole.

Other Information About Triazole

1. 1,2,3-Triazole Synthesis

Substituted 1,2,3-triazole can be synthesized by Huisgen cycloaddition, a 1,3-dipolar cycloaddition reaction of an azide with an alkyne, useful in click chemistry. The Dimroth rearrangement is an example of ring-chain tautomerism involving 1,2,3-triazole.

2. Characteristics of 1,2,4-Triazole

1,2,4-Triazole is a colorless, needle-like crystal with melting and boiling points of 120 °C and 260 °C, respectively. It is planar and soluble in water and ethanol. 1,2,4-triazole undergoes both N-protonation and deprotonation in aqueous solution. It is a key component of the antifungal drug fluconazole.

3. Synthesis of 1,2,4-Triazole

Unsubstituted 1,2,4-triazole is synthesized from thiosemicarbazide and formic acid, followed by oxidation with nitric acid or hydrogen peroxide. The Einhorn-Brunner and Pellizzari reactions are also used for its synthesis.

What Is Trimethylbenzene?

Trimethylbenzene is an aromatic hydrocarbon with the chemical formula C9H12 and a molecular weight of 120.19. It is a colorless liquid with a characteristic odor, consisting of three isomers where three hydrogen atoms on the benzene ring are replaced with methyl groups.

The isomers include:

• 1,2,3-Trimethylbenzene (Hemimellitene), with methyl groups at the first, second, and third positions.
• 1,2,4-Trimethylbenzene (Pseudocumene), with methyl groups at the first, second, and fourth positions.
• 1,3,5-Trimethylbenzene (Mesitylene), with methyl groups at the first, third, and fifth positions.

All are obtained from high-boiling fractions of tar gas oil.

Uses of Trimethylbenzene

Trimethylbenzene is primarily used as a raw material for the synthesis of pigments, dyes, pharmaceuticals, and industrial chemicals. 1,2,4-trimethylbenzene serves as a gasoline additive and an SD solvent. 1,3,5-trimethylbenzene is used as a high-boiling solvent and an etchant in semiconductor wafer mapping.

Other Information on Trimethylbenzene

1. Properties of Trimethylbenzene

Trimethylbenzene has a melting point ranging from -2 to -45 °C, a boiling point of 165 to 176 °C, a flash point of 44 to 53 °C, and a specific gravity of 0.86 to 0.89 g/mL. It is insoluble in water but soluble in organic solvents. Each isomer has specific properties such as melting points, boiling points, specific gravities, and odors.

2. Production Process of Trimethylbenzene

Trimethylbenzene is found in kerosene, diesel oil, and gasoline, and can be obtained by distilling and refining crude oil. It is also synthesized through methods such as dehydration and condensation of acetone using tantalum- or niobium-based catalysts, or by trimerization of propine in sulfuric acid.

3. Handling of Trimethylbenzene

Trimethylbenzene should be handled in a closed container and stored in a cool, well-ventilated place, away from ignition sources. It is extremely flammable and can form explosive mixtures with air. Oxidizing materials should be avoided, and protective measures such as gloves, eye protection, and masks are recommended. Only use it outdoors or in well-ventilated areas and avoid inhalation of mists, vapors, and sprays.

What Is Trimethylsilane?

Trimethylsilane is an organosilicon compound with the chemical formula C3H10Si and CAS number 993-07-7. It is a colorless gas at room temperature, nearly odorless or with a faintly unpleasant odor. It has a molecular weight of 74.2, a melting point of -135.9 °C, a boiling point of 6.7 °C, a density of 0.638 g/cm³, and a specific gravity of 2.6, making it heavier than air. Its solubility is not well defined, but it does not react violently with water.

Trimethylsilane has a flash point below -20 °C, making it highly flammable. It ignites at room temperature but is not spontaneously combustible.

Uses of Trimethylsilane

Trimethylsilane’s primary use is in semiconductor manufacturing, particularly as a raw material for film deposition in low-k dielectric constant interlayer insulating film formation using the plasma CVD method. It is utilized for SiC, SiOC, SiO2, and SiN film materials.

Purification is crucial for its use in semiconductor production, with typical impurities including methylsilane, dimethylsilane, silane, and unreacted chlorosilane. Common purification methods include distillation, recrystallization, reprecipitation, sublimation, activated carbon filtration, and washing with an absorption solution in the pH range of 2 to 4.

Principle of Trimethylsilane

1. Method for Synthesizing Trimethylsilane

Trimethylsilane is synthesized primarily by reducing trimethylchlorosilane ((CH3)SiCl) using agents such as lithium aluminum hydride (LiAlH4) in DME or aromatic hydrocarbon solvents, lithium hydride (LiH), or diethylaluminum hydride ((C2H5)2AlH).

2. Chemical Properties of Trimethylsilane

At room temperature and atmospheric pressure, trimethylsilane is stable but may decompose to silicon carbide and hydrogen at temperatures above 500 °C. It is a flammable gas, igniting at room temperature with an ignition point of 310 °C. Proper handling to avoid fire and static electricity is necessary.

Types of Trimethylsilane

Trimethylsilane is available as high-pressure and liquefied gas products, mainly for industrial use. Storage requires keeping the container below 40 °C, in a dry, well-ventilated area away from direct sunlight. As a flammable gas, it must be stored away from fire and combustible materials.