月: 2023年3月

What Is Octane?

Octane is the generic name for saturated hydrocarbons (alkanes) consisting of eight carbons, with 24 isomers including 18 structures of isomers and 6 stereoisomers. It is a key component in crude oil and petroleum, used industrially in various applications.

Uses of Octane

Octane serves primarily as a solvent in standard fuels, organic synthesis, and azeotropic distillation. It is used in solvents for nitrocellulose, acetylcellulose, synthetic resins, alcohol-soluble dyes, moisture-proof cellophane adhesives, quick-drying varnishes, and enamels. Isooctane, a branch of n-octane, is crucial for measuring octane numbers in fuels.

Properties of Octane

The molecular formula of n-Octane is C8H18, with a molecular weight of 114.22. It is a clear, colorless liquid with a gasoline-like odor, a melting point of -56.76°C, and a boiling point of 125.67°C. Octane is almost insoluble in water, soluble in ethanol and acetone, and miscible with benzene. It is highly flammable, and combustion produces toxic gases like carbon monoxide and carbon dioxide.

Other Information on Octane

1. Toxicity of Octane

Octane can cause skin and eye irritation, drowsiness, and dizziness, and is toxic if swallowed or inhaled. It poses environmental hazards to aquatic life. Proper disposal by specialized waste disposal companies is required.

2. Precautions When Handling Octane

Protective gloves, clothing, and eye protection are recommended during handling. Explosion-proof electrical, ventilation, and lighting equipment are essential, along with measures against electrostatic discharge. Facilities like eye washers and safety showers should be accessible in the work area.

3. How to Store Octane

Octane should be stored in fireproof, noncombustible structures with impermeable floors. Containers should be sealed and stored in a cool, well-ventilated place, away from heat, sparks, flames, and oxidizers.

What Is Terramycin?

Terramycin, also known as oxytetracycline, is a broad-spectrum antibiotic isolated from the actinomycete Streptomyces rimosus. It belongs to the tetracycline antibiotics class and binds to the 30S ribosomal subunit of bacteria to inhibit protein synthesis, exhibiting bacteriostatic activity.

Uses of Terramycin

Terramycin is used in human medicine to treat various bacterial infections, including acne, chlamydia infections, mycoplasma infections, Haemophilus influenza, and rickettsial infections. It is also widely used in veterinary medicine and as a pesticide against bacterial diseases of crops.

Properties of Terramycin

The chemical formula of Terramycin is C₂₂H₂₄N₂O₉, with a molecular weight of 460.434 g/mol. It is a yellow crystal, soluble in water and slightly soluble in ethanol. The in vivo half-life is 6-8 hours.

Other Information on Terramycin

1. Terramycin Efficacy

Terramycin has a broad antibacterial spectrum, effective against gram-positive and gram-negative bacteria, Chlamydia, and Mycoplasma, although some bacteria may develop resistance.

2. Terramycin Side Effects

Topical application may cause itching and swelling. Internal use can lead to gastrointestinal symptoms, photosensitivity, and, rarely, damage to high-calcium organs like teeth and bones.

3. Tetracycline Antibiotics Other Than Terramycin

Similar natural tetracycline antibiotics include tetracycline and chlortetracycline. Chlortetracycline differs from tetracycline by the substitution of a chlorine atom.

4. Substances Related to Terramycin

Terramycin is prescribed for 6-8 weeks for moderate to severe acne, but alternative treatments should be considered if there is no improvement after 3 months. It is also effective against clostridial and spirochete infections and can be used for patients allergic to penicillins or macrolides. Doxycycline, with improved pharmacological properties, is often chosen for treating various infections.

What Is Ethylene Glycol Monoethyl Ether?

Ethylene glycol monoethyl ether is an organic compound with one hydroxy group and one ether bond in the molecule. It has a molecular formula of C4H10O2, a molecular weight of 90.12, a melting point of -70°C, and a boiling point of 135°C. It is a colorless liquid at room temperature with a characteristic ether odor. It has a density of 0.9297 g/cm3 (at 20°C), is freely miscible and soluble in water, and is a flammable liquid and vapor with a flash point of 45°C. It may corrode light metals such as copper and aluminum.

Uses of Ethylene Glycol Monoethyl Ether

Ethylene glycol monoethyl ether is primarily used as a solvent for resins, paints, and printing inks. It also serves in dyeing leather goods, as a stain remover in cleaning, and for dissolving stains. Additionally, it is utilized as a solvent for coating epoxy resins on metal and mechanical parts.

Principle of Ethylene Glycol Monoethyl Ether

The principle of ethylene glycol monoethyl ether involves its synthesis and chemical reactions.

1. Synthesis of Ethylene Glycol Monoethyl Ether

It is synthesized by reacting oxirane (ethylene oxide) with ethanol in the presence of a base.

2. Chemical Reaction of Ethylene Glycol Monoethyl Ether

This compound is miscible with alcohols, acetone, ethers, and liquid esters, besides water, with a pKa of 14.8. It reacts at the hydroxy group like common alcohols.

Types of Ethylene Glycol Monoethyl Ether

Ethylene glycol monoethyl ether is widely used as an ether solvent, often sold under the trade name “ethyl cellosolve” in various capacities. Available in single-liter cans to 190 kg drums, it is stored at room temperature. Smaller volumes such as 500mL are also available for chemical synthesis.

What Is Ethyleneimine?

Ethyleneimine, also known as aminoethylene, is a clear, colorless liquid with a strong ammonia odor. It is miscible in water and soluble in organic solvents such as ethanol. The vapor is heavier than air and can form explosive mixtures. It is highly corrosive and can corrode plastics, metals, and glass.

Ethyleneimine is produced by reacting chloroethylamine or aminoethyl sulfuric acid with sodium hydroxide.

Uses of Ethyleneimine

Ethyleneimine is used in various fields such as papermaking, fiber fixing agents, liquid purification agents, dispersing agents, antibacterial and sterilizing polymers, electronic and electric materials, and water-based paints. It serves as a raw material for organic synthesis, including taurine, and polyaziridine production.

Ethyleneimine is highly toxic and can cause symptoms like nausea, vomiting, headache, breathlessness, and pulmonary edema upon inhalation.

What Is Uridine?

Uridine is a substance having the structure of uracil attached to the ribose ring.

It is a nucleotide and a component of ribonucleic acid (RNA). It is widely found in the biological world in the form of nucleotides. Uridine is administered as a drug to patients with orotic aciduria, while its derivatives are used as raw materials for umami seasonings.

Uses of Uridine

Uridine was used in the development of an RNA vaccine against the novel coronavirus; once in the body, the RNA vaccine acts as RNA inside cells to stimulate acquired immunity.

The RNA that makes up the RNA vaccine is composed of pseudouridine, which replaces the uridine portion of the RNA that occurs naturally in the human body. Pseudouridine is an isomer of uridine.

Approved RNA vaccines include those developed by Moderna and those developed jointly by Biontec and Pfizer.

Properties of Uridine

Uridine is a colorless, long-needled crystal with a melting point of 165°C. It is soluble in water, pyridine, and DMSO.

The absorption maximum wavelength is 262 nm at pH 2. It is not easily hydrolyzed by dilute acids. However, it is hydrolyzed to uracil and furfural by concentrated acids.

Structure of Uridine

Uridine has the structure of a β-N1-glycosidic bond of uracil, one of the bases of DNA, to ribose. The chemical formula is C9H12N2O6 and the molar mass is 244.203.

Uridine has a pyrimidine skeleton. Therefore, it can be synthesized based on pyrimidine. For example, it can be synthesized from 2,6-diethoxypyrimidine and acetobromoribofuranose. It can also be obtained by hydrolysis of ribonucleic acid or enzymatic treatment of uridilic acid.

Other Information on Uridine

1. Physiological Effects of Uridine

It has been reported that the simultaneous administration of ω3 fatty acids with uridine has antidepressant effects in rats. It has also been reported that the simultaneous administration of uridine, ω3 fatty acids, and choline activates synapses and increases protein and phospholipid levels in the rat.

2. Structure of Uridine

Uridine is composed of ribose and uracil. Ribose is a type of monosaccharide. D-ribose is an aldose with a carbon chain length of 5, and its counterpart ketose is ribulose.

3. Compounds Containing Uridine

Compounds containing uridine are known as uridine diphosphate galactose and uridine 5′-diphosphoglucose. These compounds function as coenzymes in the biosynthesis of polysaccharides and glycosides.

4. Related Compounds of Uridine

Deoxyuridine is a compound in which uracil is attached to the deoxyribose ring. It is similar to the chemical structure of uridine, but deoxyuridine does not have a 2′-hydroxy group.

What Is Uracil?

Uracil is a pyrimidine base with the chemical formula C4H4N2O2 and is one of the four nucleobases that constitute ribonucleic acid (RNA). It is represented by the letter U in RNA sequences and is a colorless solid with a molecular weight of 112.09.

While bases such as adenine, guanine, and cytosine are found in both DNA and RNA, uracil is exclusive to RNA, replacing thymine in DNA sequences during transcription to RNA.

Uses of Uracil

Uracil is a crucial component of RNA, playing a vital role in genetic information transmission and protein synthesis. It is also used in the pharmaceutical industry as a synthetic ingredient in anticancer drugs, including fluorouracil (5-FU), a fluorinated derivative effective against various cancers.

Properties of Uracil

Uracil is slightly soluble in water and soluble in alcohol. It undergoes oxidation, nitration, and alkylation, and forms base pairs with adenine in RNA. In the presence of phenol and sodium hypochlorite, uracil is visible under UV light. Thymine in DNA is produced by methylation of uracil.

• Chemical formula: C4H4N2O2
• Molecular weight: 112.09 g/mol
• Appearance: White crystalline powder
• Melting point: 335-338°C
• Boiling point: 440°C

Structure of Uracil

Uracil, like cytosine and thymine, has a pyrimidine ring and easily forms ribonucleosides like uridine. Phosphorylation of uridine leads to the production of UMP, UDP, and UTP, each playing a vital role in biological functions.

Uracil reacts with anhydrous hydrazine to open its ring, forming an anion at a pH above 10.5.

Other Information on Uracil

Mechanism of Action of Fluorouracil

Fluorouracil is a fluoropyrimidine antimetabolite, acting as an inhibitor of thymidylate synthase and disrupting DNA synthesis. Its metabolite, FdUMP, inhibits DNA synthesis, while FUTP, another metabolite, interferes with RNA processing and mRNA translation.

What Is Indene?

Indene is a component of coal tar, found in the distillation distillate of coal tar neutral oil and refined by removing tar acids. Pure indene is colorless, turning pale yellow due to polymerization or oxidation during storage. It is unstable and prone to polymerization reactions, absorbing oxygen to form oxides. When heated, it decomposes, emitting irritating smoke and gases.

Uses of Indene

Indene is used in organic synthesis for optical functional materials, functional resins, and pharmaceutical intermediates. It serves as a resin modifier in the polymerization of coumarone and styrene, enhancing the properties of various resins. Coumarone-indene resin, different from petroleum resins, offers adhesiveness, mechanical, and electrical properties, and is used in rubber, paints, and epoxy resins.

Properties of Indene

Indene, a bicyclic hydrocarbon with a molecular formula of C9H8, is a colorless oily liquid at room temperature, insoluble in water but soluble in organic solvents like ethanol and acetone. It has a melting point of -1.8°C and a boiling point of 181.6°C, and is highly irritating to eyes and skin, with potential damage to kidneys, liver, and spleen upon inhalation.

Other Information on Indene

1. Purification of Indene

Indene is obtained from coal tar fractions, extracted by steam distillation after reacting with metallic sodium to form a salt.

2. Indene Reactions

Indene undergoes various reactions, including oxidation to form homophthalic acid, and condensation with ethyl oxalate and ketones or aldehydes to yield indene-oxalate and benzofulvene, respectively.

3. Indene as a Ligand

Indene forms the indenyl anion upon proton withdrawal, acting as an η3- ligand and exhibiting the indenyl effect.

4. Indene in Resin Synthesis

Indene, when polymerized with coumarin, forms a thermoplastic resin with a low degree of polymerization. The resulting coumarone-indene resin, obtained from the 160-180°C fraction of coal tar, is brown or black, soluble in aromatic hydrocarbons, and resistant to acids and alkalis.

What Is Imidazole?

Imidazole is a type of heterocyclic compound containing two nitrogen atoms. Other names include 1H-imidazole, glyoxane and 1,3-diazole,

Imidazole is also referred to as a generic term for a group of compounds with substituents on the nitrogen or carbon forming the imidazole ring.

Uses of Imidazole

Imidazole is widely used industrially as a raw material for chemicals, agrochemicals, and pharmaceuticals. In particular, it is often used as a semiconductor encapsulant and adhesive, as it exhibits excellent properties in areas around electronic substrates where heat resistance is required.

It is are also widely used in various other industrial fields, such as curing agents and accelerators for epoxy resins, urethane foaming catalysts, rust inhibitors, rubber vulcanization accelerators, paints, adhesives, construction materials, and sporting goods.

As a base catalyst type curing agent or accelerator, it is characterized by its excellent storage stability, such as curing with the addition of a relatively small amount.

In pharmaceutical applications, imidazole is used in antifungal agents, and imidazoles with substituents attached to the imidazole ring are also used in many pharmaceuticals, including anti-ulcer, anti-hypertensive, and anti-asthmatic agents. In addition, imidazolium salts containing imidazolium cations, which are quaternary amines formed by alkyl addition to the nitrogen of imidazole, have become ionic liquids, neutralized salts with melting points near room temperature, and are attracting attention as green solvents, which are environmentally friendly solvents.

Properties of Imidazole

Imidazole is a white to pale yellow flaky solid with molecular formula C3H4N2 and molecular weight of 68.08. It has a melting point of 88~92°C, a boiling point of 256°C, and a flash point of 145°C.

Imidazole is sublimable. It is soluble in solvents of high polarity, easily soluble in water, methanol, and ethanol, soluble in pyridine and chloroform, insoluble in ether and benzene of low polarity, and nearly insoluble in hexane.

It forms complexes with many transition metal ions and functions as an excellent ligand. It is resistant to thermal decomposition and relatively stable against oxidizing and reducing agents. It exhibits strong aromaticity and is susceptible to hydrogen atom substitution reactions.

Imidazole retains its symmetrical structure by taking on a resonance structure even when the proton at position 1 is removed or the nitrogen at position 3 is protonated. This allows the charge to be dispersed without loss of aromaticity.

Types of Imidazole

There are various derivatives with substituents attached to the imidazole ring, and these are called imidazoles. Substituents are attached to the nitrogen at the 1-position and the carbons at the 2-, 4-, and 5-positions, and it is possible to synthesize derivatives with different substituents at each position. The nitrogen at position 3 can also be cationized by nucleophilic substitution, but substituents can be attached.

Typical imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, and 2-phenylimidazole, where the prefix number indicates to which site of the ring the substituent is attached. Acylated imidazoles are sensitive to nucleophilic reactions and are used in the synthesis of carboxylic acid derivatives.

Imidazole is also commonly used as a base and catalyst in the protection of hydroxyl groups as silyl ethers by the action of silyl chlorides. Additionally, carbonyldiimidazoles (CDIs) are useful as carbonylating agents and amide condensing agents.

Other Information on Imidazole

How Imidazoles are Manufactured

Imidazole can be produced by the reaction of glyoxal with aldehydes and ammonia, or by synthesis from ethylenediamine and nitriles.

1. Synthesis from glyoxal
The type of aldehyde or amine used as a raw material determines the substituent at the 1- and 2-positions.

OHC-CHO + R1-NH2 + R2CHO → R1R2C3H2N2 + 3H2O

2. Synthesis from ethylenediamine
The substituent at the 1- and 2-positions is determined by the substituent of the nitrile.

H2N-CH2CH2-NH2 + RCN → R2C3H4N2 + NH3 → R2C3H2N2 + H2

What Is Inosine?

Inosine is an organic compound with the chemical formula C10H12N4O5, also known as hypoxanthosine or hypoxanthine riboside. It is an N-riboside consisting of hypoxanthine (6-hydroxypurine) and D-ribose. Its CAS registry number is 58-63-9.

With a molecular weight of 268.23, a melting point of 226°C, and a nearly white crystalline powder form at room temperature, inosine is soluble in water and has a solubility of 1.6g/100mL at 20°C. However, it is practically insoluble in ethanol.

Uses of Inosine

Inosine has various applications in the medical and food industries. It’s a component of umami flavor and is used in the treatment of radiation exposure, drug-induced leukopenia, and subacute sclerosing panencephalitis. Additionally, inosine is used as a dietary supplement for its potential to activate the ATP cycle and enhance endurance.

Properties of Inosine

Biochemically, inosine is a trace base rarely found in RNA but often present in tRNA, especially in the anticodon site. It can be associated with various nucleobases through hydrogen bonds. Inosine is abundant in muscle tissue and undergoes hydrolysis into hypoxanthine and D-ribose when heated in dilute sulfuric acid.

Types of Inosine

Inosine products include pharmaceuticals, supplements, and research reagents, available in capacities suitable for laboratory and industrial applications. They are typically handled at room temperature.

Other Information on Inosine

1. Synthesis of Inosine

Inosine can be obtained by fermenting adenosine with adenosine deaminase and is also produced by the degradation and synthesis of inosinic acid.

2. Related Substances of Inosine

Inosinic acid, with phosphate at the 5′ position of the ribose moiety in inosine, is a tastant nucleotide found in meat. The sodium salt of inosinic acid is a key umami compound in dried bonito flakes. In vivo, inosine is synthesized from xanthine and converted to inosinic acid via the salvage pathway.