月: 2023年4月

What Is Nitrophenol?

Nitrophenol is an organic compound where a nitro group is bonded to phenol. It exists in three forms, distinguished by the nitro group’s position: 2-nitrophenol (o-nitrophenol), 3-nitrophenol (m-nitrophenol), and 4-nitrophenol (p-nitrophenol). Among these, 4-nitrophenol is the most commonly utilized. It is known to irritate the skin and mucous membranes, necessitating caution to avoid prolonged exposure.

Uses of Nitrophenol

1. Synthesis of Phenetidine and Acetophenetidine

4-nitrophenol is employed in synthesizing phenetidine and acetophenetidine. Phenetidine, once used in the artificial sweetener dultin’s production, is now utilized as an intermediate for azo dyes and pharmaceuticals. Meanwhile, acetophenetidine, or phenacetin, serves as an antipyretic and analgesic. However, its usage has declined due to the risk of kidney damage from long-term, high-dose consumption.

2. PH Indicator

4-nitrophenol transitions from colorless in acidic solutions to yellow in alkaline solutions, making it useful as a pH indicator. This change occurs when the hydroxyl group on nitrophenol donates an H+ ion to the base OH-, forming the nitrophenol anion, which absorbs violet light and reflects yellow, turning the solution yellow.

3. Fungicides/Insecticides

Due to its strong protein coagulation and denaturation capabilities, nitrophenol is used as a fungicide and insecticide. Its effective penetration into bacteria also makes it suitable for wood preservation, combating wood-decaying fungi.

Properties of Nitrophenol

1. Acidity

Nitrophenol, with its nitro group (-NO2) attachment to phenol, exhibits relatively strong acidity. Phenols are more acidic than alcohols due to the stability of their conjugate base, which is enhanced by the electron-withdrawing effect of the nitro group, making nitrophenol more acidic than phenol itself.

2. Solubility

The polarity introduced by the nitro group enhances nitrophenol’s solubility in water and various organic solvents, as well as in alkaline solutions, due to its ease of ionization and the strong electron-withdrawing properties of the nitro group.

3. Crystal Polymorphism

4-nitrophenol exhibits two polymorphic forms in its crystalline state: the α form, a colorless columnar crystal unstable at room temperature but stable to sunlight, and the β form, a yellow columnar crystal that is stable at room temperature but turns red upon sunlight exposure.

Structure of Nitrophenol

Nitrophenol’s structure involves replacing one hydrogen atom on the benzene ring of phenol with a nitro group (-NO2), leading to three isomers based on the nitro group’s position relative to the hydroxyl group (ortho, meta, para). These isomers, namely 2-nitrophenol, 3-nitrophenol, and 4-nitrophenol, exhibit distinct properties such as melting points, boiling points, and solubility in water, influencing their reactivity and applications.

Other Information about Nitrophenol

Synthesis of Nitrophenol

Nitration of phenol with dilute nitric acid produces a mixture of 2-nitrophenol and 4-nitrophenol, which can be separated by distillation due to their different boiling points. Additionally, 3-nitrophenol can be synthesized from p-nitrochlorobenzene through hydrolysis and acidification or by diazotizing m-nitroaniline and hydrolyzing the diazonium group.

What Is Nitroaniline?

Nitroaniline is an organic compound belonging to the aromatic amine family, in which one hydrogen atom on the aromatic ring of aniline is replaced by a nitro group.

The chemical formula is C₆H₆N₂O₂, with a molecular weight of 138.126. There are three isomers, depending on the position of the nitro group: 2-Nitroaniline (o-Nitroaniline), 4-Nitroaniline (p-Nitroaniline), and 3-Nitroaniline (m-Nitroaniline).

Generally, 4-nitroaniline is the most widely used, with CAS registration numbers 88-74-4 (2-nitroaniline), 99-09-2 (3-nitroaniline), and 100-01-6 (4-nitroaniline).

Uses of Nitroaniline

Nitroaniline is primarily used as an intermediate in the synthesis of dyes, pharmaceuticals, antioxidants, gasoline gum inhibitors, poultry medications, and corrosion inhibitors. 4-nitroaniline serves as a raw material for the synthesis of the red azo dye, Para Red.

Para Red, developed in 1880, was the world’s first azo dye and remains significant for its easy coloring, deep coloration, and excellent light and heat resistance.

3-Nitroaniline is used as a synthetic intermediate, especially for azo dyes, from which yellow and blue dyes are synthesized.

Properties of Nitroaniline

1. Basic Information on 2-Nitroaniline

2-nitroaniline, an orange crystal at room temperature, has a melting point of 71-72°C and a boiling point of 284°C. It is slightly soluble in ethanol and diethyl ether, and very insoluble in water.

2. Basic Information on 3-Nitroaniline

3-nitroaniline, a yellow crystal at room temperature, has a melting point of 114°C and a boiling point of 306°C. It is slightly soluble in ethanol and diethyl ether, and very insoluble in water.

3. Basic Information on 4-Nitroaniline

4-nitroaniline, the most versatile of the three isomers, appears as a yellow or yellowish-red powder or crystal at room temperature. It has a melting point of 148°C, a boiling point of 332°C, and a density of 1.437 g/mL. It is slightly soluble in ethanol and diethyl ether, and very insoluble in water.

Types of Nitroaniline

Nitroaniline is commonly sold as a reagent for research and development purposes, with 4-nitroaniline being the most common, followed by 2-nitroaniline and 3-nitroaniline. Available volumes include 25 g, 500 g, and other manageable sizes for laboratory use, typically stored at room temperature.

Other Information on Nitroaniline

1. Synthesis of Nitroaniline

4-nitroaniline and 2-nitroaniline can be synthesized from aniline through the following steps:

1. Protection of the amino group of aniline with an acetyl group (to produce acetanilide).
2. Nitration of the resulting acetanilide with mixed acid (aromatic nucleophilic substitution reaction).
3. Purification and separation of 2-nitroacetanilide and 4-nitroacetanilide.
4. Deprotection of the acetyl group through hydrolysis.

Due to the ortho-para directing nature of these reactions, 3-nitroaniline cannot be synthesized by this method but can be produced through the nitration of benzamides followed by a Hofmann rearrangement.

2. Chemistry of 4-Nitroaniline

A notable chemical reaction involving 4-nitroaniline is the synthesis of the azo dye Para Red, which is achieved by diazotization of 4-nitroaniline followed by coupling with β-naphthol. For dyeing, the fiber is immersed in an aqueous alkaline solution of β-naphthol before the coupling reaction is conducted on the fiber.

What Is Naphthoquinone?

Naphthoquinone is an organic compound consisting of two oxygen atoms bonded to naphthalene, forming a quinone structure.

There are mainly two types of naphthoquinones: 1,4-naphthoquinone and 1,2-naphthoquinone, with 1,4-naphthoquinone being the more prevalent variant.

1,4-naphthoquinone, a yellow triclinic crystal at room temperature, resembles benzoquinone in aroma. It is insoluble in water but dissolves in various polar solvents. This compound exhibits acidic and oxidizing properties.

To prevent oxidation, 1,4-naphthoquinone should be stored in containers that are shielded from light and air. It can irritate the skin and mucous membranes, hence requires cautious handling. Its industrial synthesis involves the oxidation of naphthalene with a catalyst.

Uses of Naphthoquinone

Naphthoquinone serves as a precursor in synthesizing chemicals for diverse industrial uses. Through the Diels-Alder reaction with 1,3-dienes, anthraquinones are produced, which are vital for dye production and serve as a catalyst in pulp manufacturing.

Its diazo derivative, DiazoNaphthoquinone, is employed in the semiconductor industry for mercury exposure. Various naphthoquinone derivatives exhibit cytotoxic properties, making them useful in antiviral and antipyretic medications.

Reports highlight the antibacterial, antifungal, antiviral, anti-inflammatory, and anticancer effects of 1,4-naphthoquinone and its derivatives, leading to the development of new drugs. Their potent coloring properties also make them valuable as dyes and pigments, especially for red and yellow colors.

Properties of Naphthoquinone

As a naphthalene derivative, 1,4-naphthoquinone is characterized by its yellow-to-orange crystalline form and distinctive odor. It has a melting point of around 124°C and boils at over 300°C.

Its solubility in water is minimal, but it readily dissolves in polar organic solvents like alcohols, ethers, and acetone. The compound’s quinone structure enables easy reduction to a hydroquinone form, and it is prone to oxidation in air, necessitating careful storage.

Structure of Naphthoquinone

The structure of 1,4-naphthoquinone features carbonyl groups at the 1 and 4 positions of naphthalene, forming a planar, conjugated system. This structural arrangement allows for the absorption of ultraviolet and visible light, making it suitable for use in dyes and pigments.

Its molecular formula is C₁₀H₆O₂, with the IUPAC name “4H-cyclopenta[def]phenanthrene-4,5-dione.” The compound’s structure is foundational to several biologically significant compounds, including vitamin K and ubiquinone (coenzyme Q).

Other Information on Naphthoquinone

Naphthoquinone Production Method

The primary source of 1,4-Naphthoquinone is naphthalene, converted to Naphthoquinone using oxidizing agents like sodium chromate. Other synthesis methods include the ring condensation of anthraquinone derivatives and the oxidation of 1,4-naphthol.

What Is Tropolone?

Tropolone is an aromatic organic compound where the 2-position of tropone is substituted by a hydroxy group.

Tropone, also known as 2,4,6-cycloheptatrien-1-one, is a nonbenzenoid aromatic ring comprising seven carbon atoms featuring three conjugated alkenes and a carbonyl group.

Tropolone, alternatively called hydroxytropolone or 2-hydroxy-2,4,6-cycloheptatrien-1-one, possesses a hydroxy group adjacent to the carbonyl group.

Uses of Tropolone

Hinokitiol, a derivative of tropolone, occurs naturally in the essential oils of cypress trees like Formosan red cypress and Aomori cypress. Exhibiting antibacterial properties against various bacteria including Escherichia coli and Staphylococcus aureus, hinokitiol finds application as an antiseptic in skincare and cleansing products.

Moreover, hinokitiol has been reported to inhibit the growth of Malassezia, the bacterium responsible for dandruff, making it a common ingredient in anti-dandruff shampoos and scalp care products.

Properties of Tropolone

Tropolone has a melting point ranging from 50-52°C, a boiling point of 290°C, and a flash point of 112°C. It appears as a pale yellow solid at room temperature.

It is soluble in various organic solvents such as ether, ethanol, and benzene. With two oxygen atoms, tropolone readily forms chelates upon reacting with different metals.

The hydroxyl group in tropolone exhibits weak acidic properties akin to phenol, with an acid dissociation constant (pKa) of 6.89. It produces a dark green color reaction when treated with iron chloride.

Structure of Tropolone

The chemical formula of tropolone is C₇H₆O₂, with a molar mass of 122.12 g/mol and a density of 1.1483 g/mL.

Featuring a seven-membered ring structure, tropolone is aromatic. The ring constitutes a 6π-electron system, with the negative charge being biased towards the oxygen atom.

The hydroxy and carbonyl groups in tropolone are indistinguishable, and the tropolone nucleus is stabilized by a hybridization of resonance structures. With six possible limiting structural formulas, the properties of the hydroxy and carbonyl groups are nearly identical.

Natural compounds with tropolone as a backbone include hinokitiol, colchicine, and pulprogarin, with stipitatinic acid demonstrating specific antimicrobial properties.

Other Information on Tropolone

1. Synthesis of Tropolone

Tropolone can be synthesized through various methods. One approach involves bromination of 1,2-cycloheptanedione using N-bromosuccinimide, followed by dehalogenation at high temperatures.

Alternatively, it can be synthesized via the acyloin condensation of diethyl pimelate, followed by the oxidation of the resulting acyloin with bromine.

Furthermore, [2+2] cycloaddition of cyclopentadiene with ketene yields bicyclo[3.2.0]heptyl, which upon hydrolysis forms a monocyclic ring to yield tropolone.

2. Reactions of Tropolone

Tropolone readily undergoes O-alkylation to produce cycloheptatrienyl derivatives, serving as a versatile synthetic intermediate.

When treated with sulfamic acid, nitric acid, or bromine, tropolone undergoes electrophilic substitution to yield sulfonic acids, nitro compounds, and bromo compounds, respectively. It also undergoes diazo coupling with diazonium salts.

Deprotonation by metal cations results in the formation of bidentate ligands, as seen in the Cu(O₂C₇H₅)₂ complex.

What Is DABCO?

DABCO is a white crystalline powder of tertiary amines.

Its IUPAC name is 1,4-diazabicyclo [2,2,2] octane, also known as 1,4-ethylenepiperazine, DABCO, and TEDA.

DABCO is a registered trademark (No. 551479) of Air Products & Chemicals, Inc. DABCO is not subject to any major national regulations.

Applications of DABCO

1. Foaming Catalyst for Polyurethane Foam

DABCO is mainly used as a catalyst for polyurethanation reactions. It is dissolved in crystalline form or with diprovylene glycol, etc., and the polyaddition reaction and the foaming reaction proceed in a well-balanced manner. Soft, hard, semi-hard, urethane paints and urethane elastomers can be produced.

2. Low-Molecular-Weight Organic Synthesis Reaction

DABCO is used as a bulky base in small-molecule organic synthetic chemical reactions. A well-known example of its use is the Morita-Baylis-Hillman reaction. DABCO is a nucleophilic catalyst in the reaction.

When aldehydes or imines react with alkenes substituted with electron-withdrawing groups in the presence of DABCO, new carbon-carbon bonds are formed. The reaction proceeds by a Michael-Aldol-like mechanism.

In addition, it is used as a catalyst for metal complex salt formation, dehalogenation agent, cyanoethylation catalyst, ester exchange catalyst, and epoxy resin curing catalyst.

Properties of DABCO

The chemical formula is C₆H₁₂N₂ and the molecular weight is 112.17. The CAS number is 280-57-9.

Its melting point is 158 °C and its boiling point is 174 °C. It is hygroscopic and sublimates and exists as a solid at room temperature. The compound has an ammonia-like odor and is well soluble in water, ethanol, acetone, and chloroform.

It has a pH of 10.8, which indicates the degree of acidity or alkalinity, and acid dissociation constants (pKa) of 3.0 and 8.6. The acid dissociation constant is a quantitative measure of the strength of an acid; a smaller pKa indicates a stronger acid.

The basicity of DABCO is comparable to other tertiary amines, but it has high nucleophilicity due to its fixed structure, which leaves unshared electron pairs exposed.

Other Information on DABCO

1. Production Method of DABCO

DABCO is synthesized by cyclization of amine compounds using zeolite as a catalyst. Ethylenediamine,monoethanolamine, diethanolamine, and diethylenetriamine can be used as amine compounds.

2. Handling and Storage Precautions

Handling Precautions
Avoid contact with strong oxidizing agents. There is a risk of respiratory irritation. Use in a draft chamber with local exhaust ventilation. Wear personal protective equipment when using.

In Case of Fire
Thermal decomposition may release corrosive and toxic gases and vapors. Use water spray, foam, powder extinguisher, carbon dioxide, or extinguishing sand to extinguish fire.

For Storage
DABCO may be altered by light. During storage, place in polypropylene or polyethylene containers and seal tightly. Store locked up in a well-ventilated and as cool a place as possible, away from direct sunlight.

What Is Dehydrocholic Acid?

Dehydrocholic acid, also known as dehydicholic, is an organic compound. This odorless, white to slightly yellow solid is soluble in ethanol but almost insoluble in water.

Dehydrocholic acid is a semi-synthetic bile acid derived from the oxidation of cholic acid found in bovine bile. It serves as a cholecystokinin, aiding in digestion by increasing bile volume and components.

As an amphiphilic molecule, dehydrocholic acid not only functions as a medication but also as an emulsifier, enhancing the solubility of other drugs in water.

Uses of Dehydrocholic Acid

Dehydrocholic acid is utilized in medical treatments related to digestion and lipid absorption, notably in conditions like cholangiohepatitis and bile duct disorders, to enhance bile secretion. It also plays a role in lipid digestion by activating enzymes such as lipase.

While effective, its use can lead to side effects including diarrhea and abdominal discomfort, necessitating cautious application.

Additionally, its amphiphilic nature allows for its use as an emulsifier in drug formulations, making fat-soluble drugs easier to disperse in aqueous solutions.

Properties of Dehydrocholic Acid

Dehydrocholic acid, a secondary bile acid, aids in lipid absorption and digestion by activating certain enzymes. Its structure, featuring a hydrophilic carboxyl group and a hydrophobic carbon skeleton, allows it to emulsify lipids effectively.

This acid dissolves readily in organic solvents, highlighting its potential as an additive in pharmaceutical formulations.

Structure of Dehydrocholic Acid

Dehydrocholic acid’s steroid-based structure, adorned with carboxyl groups, grants it hydrophilic properties. This structural characteristic underpins its ability to emulsify lipids, blending water and oil components effectively.

Other Information on Dehydrocholic Acid

How Dehydrocholic Acid Is Produced

Dehydrocholic acid production involves the oxidation of cholic acid, utilizing either chemical synthesis with oxidizing agents or biological methods via specific microorganisms.

1. Chemical Synthesis
This method uses oxidizing agents like hydrogen peroxide to convert cholic acid into dehydrocholic acid.

2. Biological Production
Microorganisms capable of transforming cholic acid into dehydrocholic acid are cultured, with the resulting acid extracted and purified from the culture medium.

Ensuring the purity of dehydrocholic acid requires effective separation and purification techniques, such as chromatography.

What Is Dehydroacetic Acid?

Dehydroacetic acid, a derivative of the heterocyclic compound pyrone, is denoted by the chemical formula C₈H₈O₄. It is predominantly utilized in its sodium salt form and appears as a white, powdery solid at room temperature and pressure. This compound is soluble in water and insoluble in ethanol, facilitating easy concentration adjustments via its sodium salt. 

Uses of Dehydroacetic Acid

1. Pharmaceuticals

Known for its antimicrobial efficacy against various bacteria such as black mold and Staphylococcus aureus, dehydroacetic acid exhibits bacteriostatic properties against molds, yeasts, and gram-positive bacteria within an acidic range. It is incorporated as a pharmaceutical additive for base, disintegration, antiseptic, preservation, and dissolution in oral, topical, ophthalmic, and otolaryngological formulations.

2. Cosmetics

Due to its minimal irritation potential and antimicrobial activity, dehydroacetic acid is also used as a preservative in cosmetics, including makeup, skincare, and hair care products. The inclusion of dehydroacetic acid in cosmetic formulations is capped at 0.5g per 100g to ensure safety.

3. Food Products

As a food additive, it enhances the preservative qualities of fermented foods like butter, cheese, and margarine. While approved by the Ministry of Health, Labour and Welfare, and the EU, its actual use in Japan is infrequent; however, it is specified that residual amounts in EU products should not exceed 500 mg per kg. It is also utilized in dog food preservatives, with the advisory to check ingredient labels for potential concerns.

Properties of Dehydroacetic Acid

Dehydroacetic acid is characterized as a white crystalline powder, with a molecular weight of 208.14 and assigned CAS number 64039-28-7. Absent data on its melting point, flash point, or flammability, it remains stable under typical conditions but may degrade upon light exposure. Precautions should be taken to avoid high temperatures, direct sunlight, and reactive oxidizing agents, as it may decompose into hazardous gases like carbon monoxide and dioxide.

Other Information on Dehydroacetic Acids

1. Safety Precautions

Classified with class 4 acute toxicity (oral) by the GHS, it is harmful if ingested. Immediate actions include rinsing the mouth and contacting a poison center or physician. It is essential to wash thoroughly after handling to remove potential residues.

2. First Aid Measures

In cases of inhalation, seek fresh air promptly. If contact occurs with skin or eyes, wash the area with soap and water or rinse the eyes for several minutes, respectively. Medical attention should be sought if symptoms persist.

3. Handling Guidelines

Ensure work areas are well-ventilated and equipped with safety showers and eyewash stations. Protective gear such as dust-proof masks, gloves, and goggles should be worn during handling to prevent exposure.

4. Storage Recommendations

Dehydroacetic acid should be stored in a cool, well-ventilated place away from light and strong oxidizers. Suitable containers include those made from polypropylene and polyethylene, and disposal should comply with national or local regulations.

What Is Dextran Sulfate Sodium?

Dextran sulfate sodium, the sodium salt of the sulfated ester of dextran, is a polymer of glucose. It is also referred to as a glycosaminoglycan. This compound is a mucopolysaccharide characterized by a repeating sugar chain structure, a degree of polymerization of approximately 40 or more, extensive length, and its exceptionally high hydrophilicity.

Common mucopolysaccharides include chondroitin sulfate, a primary component of cartilage, and hyaluronic acid, found in the connective tissue of the skin, umbilical cord, and the eye’s vitreous body. Dextran sulfate sodium does not fall under any specific GHS classification categories, indicating no specific hazard information, and is considered relatively safe.

Uses of Dextran Sulfate Sodium

Dextran sulfate sodium serves as a skin conditioning agent and cosmetic material, offering moisturizing effects and enhancing peripheral blood flow. Additionally, it functions as an inactive dispersant, a binding agent, a treatment for dyslipidemia (hypertriglyceridemia), and an activator of lipoprotein lipase (LPL).

Beyond these applications, it is widely used in the induction of ulcerative colitis in animal models, facilitating research into colon cancer stemming from colon inflammation.

Properties of Dextran Sulfate Sodium

An odorless white to slightly pale yellow crystalline powder, dextran sulfate sodium is identified by CAS No. 9011-18-1. It has a molecular weight range of 36,000-50,000 according to MP Biomedicals, a pH range of 4.5-8.0, and is soluble in water but virtually insoluble in ethanol and acetone. While stable under normal conditions, it should be stored away from high temperatures, direct sunlight, moisture, and strong oxidizing agents.

Other Information on Dextran Sulfate Sodium

1. Handling Methods

Minimize contact with strong oxidizers and maintain closed containers or use local exhaust ventilation. Install safety showers and hand/eye washing facilities near work areas. Protective measures for workers include masks, gloves, goggles, or full-face glasses as necessary, and long-sleeved clothing, adhering to industrial hygiene and safety standards.

Avoid ingestion, inhalation, and dermal exposure during work, ensuring thorough washing and gargling post-handling. Also, prevent contaminated protective gear from leaving the work area.

2. First Aid Measures

For inhalation, seek fresh air and medical advice if symptoms persist. In case of skin contact, wash immediately with soap and plenty of water. If the substance enters the eyes, rinse carefully for several minutes, remove contact lenses if applicable, and seek medical attention if symptoms continue. If ingested, rinse the mouth, avoid giving anything by mouth if unconscious, and consult medical professionals with SDS and handling information at hand.

3. Fire Precautions

In the event of a fire, use water spray, carbon dioxide (CO₂), foam, powder, or sand to extinguish. Since no specific fire extinguishing agent is prohibited, select an agent suitable for the surrounding environment. Firefighters should wear appropriate protective equipment, including self-contained breathing apparatus.

4. Storage Methods

Store in a cool, well-ventilated area away from direct sunlight, in tightly sealed glass containers, and distant from strong oxidizers. Dispose of this product through a licensed waste disposal contractor, following relevant regional, national, and local regulations.