月: 2023年7月

What Is Scandium?

Scandium is an element with the element symbol Sc and atomic number 21.

Scandium is a group 3 element, a rare earth element, and a transition element. It is a soft, silvery metal that forms a light yellow or light peach-colored passivity when oxidized in air. It is also characterized by its ability to react with halogen elements at room temperature.

Scandium is not a particularly rare element on earth. Its abundance is estimated to be 15-25 ppm, making it the 50th most abundant element. However, it is not present in concentrated amounts, but is found in small amounts in minerals.

Uses of Scandium

Scandium has not been widely applied to any element or compound state because of its high reactivity with halogen elements, as well as its high price. In recent years, however, it has been attracting attention as a new material.

The application that has attracted the most attention is its use in lighting. It has been reported that using scandium iodide (ScI3) in metal halide lamps produces more intense light. Other applications have also been found, such as adding Scandium to aluminum alloys and to the anode of nickel-alkali storage batteries to stabilize voltage and extend service life.

The main application of scandium by weight is in aluminum-scandium alloys, which are high-performance materials. In addition to some aerospace parts, it is used as a material for sporting goods such as bicycles, baseball, shooting, and lacrosse.

Properties of Scandium

Scandium has a specific gravity of 2.99, a melting point of 1,541°C, and a boiling point of 2,836°C. Scandium is gradually soluble in water and dilute acids. It dissolves readily in hot water and acids.

However, it does not react with a 1:1 mixture of hydrofluoric acid and nitric acid. This is believed to be due to the formation of a passive layer. When scandium is burned in air, it emits a yellow, glowing flame and forms scandium (III) oxide. The oxidation number of scandium is usually +3.

The crystal structure of scandium, which is stable at room temperature and pressure, is a hexagonal close-packed structure (HCP, α-Sc). Upon heating, there are two additional forms (β, δ). The crystal structures are cubic close-packed and face-centered cubic lattice, respectively.

Other Information on Scandium

1. Name of Scandium

The Swedish analyst Lars Fredrik Nilson named scandium from the Latin word Scandia, meaning Scandinavia.

Other known sources of Scandium include Thortveitite, Euxenite, and Gadolinite, which are rare ores produced on the Scandinavian Peninsula and Madagascar. Thortveitite, for example, contains up to 45% scandium as scandium oxide. 

2. Formation of Scandium

Electrolysis of an eutectic mixture of potassium, lithium, and scandium chloride at 700-800°C produces the metal scandium. 

3. Isotopes of Scandium

There is only one naturally occurring isotope of scandium, 45Sc. There are 13 known radioactive isotopes of scandium. The most stable of these, 46Sc, has a half-life of 83.8 days.

47Sc has a half-life of 3.35 days, 48Sc has a half-life of 43.7 hours, and all the rest have half-lives of less than 4 hours, many of them less than 2 minutes. In addition, scandium has more than 100 nuclear isomers. The mass number of isotopes of Scandium takes between 40 and 54.

Isotopes with a mass number below 45 decay by electron capture and the product is calcium. On the other hand, isotopes with a mass number greater than 45 decay, mainly by beta decay, and the decay product is titanium. Stable isotopes of scandium are synthesized by the r-process during supernova explosions.

What Is Diazomethane?

Diazomethane is an organic compound with the molecular formula CH2N2.

It is classified as a diazo compound because it has a diazo group in its molecule. Diazomethane has the simplest structure among diazo compounds, and its CAS registration number is 334-88-3.

It has a molecular weight of 42.04, a melting point of -145°C, and a boiling point of -23°C. At room temperature, it exists as a yellow gas with a musty odor. It has a density of 1.4 (air = 1). It is highly explosive and may explode on impact, heat, light, or in the presence of alkali metals.

It reacts with water, but is relatively stable in ether or dioxane solutions. Otherwise, it is readily soluble in benzene, slightly soluble in ethanol and ethyl ether, but reacts slowly with alcohols and decomposes.

It is also harmful to the human body through skin irritation and inhalation, so it should be handled with care. 

Uses of Diazomethane

The main uses of diazomethane include methylating agent, agrochemical raw material, and pharmaceutical raw material. In organic synthesis laboratories, it is used for reactions such as O-methylation of carboxylic acids and phenolic hydroxy groups (to produce methyl ether and methyl ester derivatives) and C-methylation via epoxidation of ketones, among others.

Because of its explosive nature, it is usually used in ether or dioxane solutions, which are prepared for use, but safer and easier-to-handle alternatives are very often used.

Characteristics of Diazomethane

Due to the delocalization of π-electrons, the Lewis structure of diazomethane is represented as a resonance mixture, and the molecular structure is a linear structure. It is a very unstable substance and, as mentioned above, can decompose explosively when subjected to shock, friction, or vibration.

Heating to 100°C or contact with rough surfaces are also factors that can induce explosion. Additionally, the presence of impurities or solids in undiluted liquids or concentrated solutions can also cause explosions under high-intensity light.

Types of Diazomethane

Diazomethane itself is not commercially available because it is a very unstable, dangerous, and difficult to handle substance. As mentioned above, it is usually used as an ether solution or dioxane solution, which is adjusted for use.

On the other hand, trimethylsilyl diazomethane ((CH3)3SiCHN2) is a stable, non explosive liquid with reactivity similar to that of diazomethane. Because it is easy to handle, it is also available commercially as a chemical reagent.

Except in special cases where diazomethane itself must be used, this is the most commonly used reagent, and it is also preferred from a safety standpoint. Trimethylsilyldiazomethane reagent products are usually 10% hexane solution, and are available in 5mL, 25mL, 100mL, etc. They are reagents that require refrigerated storage.

Other Information on Diazomethane

1. Synthesis of Diazomethane

Diazomethane, as mentioned above, is explosive, so it is used as an ether or dioxane solution, adjusted for use. The general method of synthesis is to react acylated or sulfonated N-methyl-N-nitrosamines with a concentrated aqueous alkaline solution.

The specific experimental operation can be obtained by the following flow.

1. Prepare a two-layer beaker with an ether or dioxane layer on top of the concentrated aqueous alkali solution.
2. Add a small amount of N-methyl-N-nitrosamine derivative while stirring under ice-cold conditions.
3. Collect the diazomethane generated in the ether layer. 

2. Chemical Reaction of Diazomethane

Diazomethane is a photolytic substance that produces methylene CH2. When reacted with acid chlorides, diazomethyl ketone or chloromethyl ketone is formed.

Reaction with active triple bonds of acetylenes and double bonds of ethylenes leads to 1,3-dipole addition reactions to form pyrazole or pyrazoline derivatives. It is also used in the ring expansion reaction of cyclic ketones in the Arndt-Eichstadt synthesis.

When used as an O-methylating agent for phenol or carboxylic acids, the reaction is generally carried out by stirring an ice-cold ether solution of an excess amount of diazomethane and adding it to a solution of phenol or carboxylic acid in small quantities.

What Is Silane Gas?

Silane gas is a hydride of silicon and is a colorless gas with a peculiar odor.

It is an inorganic compound with the chemical formula SiH4 and a molecular weight of 32.12. The hydride with one silicon (Si) is called silane (also known as monosilane), the hydride with two silicon (Si) is disilane, and the hydride with three silicon (Si) is trisilane.

Uses of Silane Gas

Silane gas is the raw material for the semiconductor silicon and is an important industrial material; it can be used in the chemical vapor deposition of silicon because silane gas decomposes into silicon (Si) and hydrogen (H) at temperatures above 420 ºC.

Compounds in which the four hydrogens of silane gas are replaced by alkoxy and alkyl groups (e.g. (CH3O)3SiCH3) are mainly used for surface treatment of inorganic fillers to improve their dispersion and flowability. Hexamethyldisilazane ((CH3)3SiNHSi(CH3)3) is used for surface treatment of inorganic materials to improve compatibility with organic resins.

Dimethylchlorosilane ((CH3)2SiHCl) is used as a raw material for silylating agents and silane gas coupling agents. They play an important role in linking organic and inorganic materials and are used in various applications, such as pharmaceutical synthesis, synthetic resins, adhesives, and glass fiber.

Furthermore, hydrolysis and polymerization of dimethylchlorosilane yields silicone fluid. Silicone is the general term for materials based on organopolysiloxanes, which are organic groups attached to siloxane bonds (alternating silicon and oxygen bonds forming a polymer).

Silicone polymers have excellent heat resistance, weather resistance, and chemical stability because the siloxane bond is the main backbone. They also have unique interfacial properties, such as water repellency and mold release properties, due to the presence of organic groups (mainly methyl groups CH3).

Polysilane gas, a silicon-based polymer compound, is known as an optoelectronic material for organic photoconductor materials, organic electroluminescence, and organic thin-film solar cells. Polydimethylsilane, a type of polysilane, is used as a raw material for silicon carbide fiber.

Properties of Silane Gas

Silane is quickly oxidized by oxygen in air and decomposes into water (H2O) and silicon dioxide (SiO2). It reacts gradually with water, so it should be handled with care. It has a melting point of -185 °C and a boiling point of -112 °C. It is insoluble in ether, benzene, chloroform, and ethanol.

Other Information on Silane Gas

1. How to Make Silane Gas

Trichlorosilane (SiHCl3), which is mainly produced by the reaction of metallic silicon (Si) with hydrochloric acid (HCl), is disproportionated using a catalyst to yield dichlorosilane (SiH2Cl2), tetrachlorosilane (SiCl4), monochlorosilane (SiH3Cl), and a mixture of silanes. Silane gas is then produced by purification and separation through distillation.

Other known industrial methods for the production of silane gas include the reduction of chlorosilane and tetraethoxysilane ((CH3CH2O)4Si), the reaction of magnesium silicide (Mg2Si) with ammonium salts, and the disproportionation of trialkoxysilane (RO3SiH).

2. Handling and Storage of Silane Gas

Silane gas is extremely flammable and combustible and can ignite spontaneously when exposed to air. It can also decompose by heating or combustion, producing silicon and hydrogen, posing a fire or explosion hazard. Therefore, it is important to store them away from ignition sources, such as heat and sparks, oxidizers, oxygen, explosives, halogens, compressed air, acids and bases.

Containers should be sealed and stored locked in a well-ventilated area at temperatures below 40°C (104°F), away from direct sunlight and fire. Also, because of the risk of skin irritation, strong eye irritation, and respiratory irritation, appropriate protective gloves, protective eyewear, and protective masks should be worn when handling, and only in well-ventilated areas.

What Is Cyclobutane?

Cyclobutane (C4H8) is a cycloalkane, also known as tetramethylene.

It is a clear, colorless, flammable liquid at room temperature that is insoluble in water and soluble in ethanol and acetone.

Cyclobutane has a square structural formula, but in reality the four carbon atoms are not in the same plane, but are bent at an angle of about 25°.

The carbon skeleton is therefore arranged at an angle of approximately 80°.

Cyclobutane, however, forms a bent bond that results in a bond angle of almost 109°, similar to the bonding in normal cycloalkanes.

Therefore, unlike cyclopropane, unsubstituted cyclobutane is less prone to ring cleavage reactions.

Uses of Cyclobutane

Cyclobutane by itself has no uses other than as a heat source, but its derivatives are used in a variety of fields.

Penitrem and grandisol are composed of cyclobutane as a derivative.

For example, cyclobutane-1,2,3,4-tetracarboxylic acid dihydride is used as a material substance in detergents and solvents and as a reactant for:

• Synthesis of biologically and pharmacologically active molecules
• Synthesis of light-sensitive polyimide materials for high-performance organic thin-film transistors
• Selective cross-linking of polyimides for use in optical devices

What Is Cycloheptane?

Cycloheptane is a cycloalkane (alicyclic organic compound) with the chemical formula C7H14.

It has a seven-membered ring structure. It is also known as heptamethylene, and its CAS number is 291-64-5. It has a molecular weight of 98.2, a melting point of -12°C, and a boiling point of 118°C. It is a colorless, oily liquid at room temperature.

The odor is described as mildly aromatic. It has a density of 0.8110 g/cm3 and is often used as a non-polar solvent. It is readily soluble in ethanol and diethyl ether, and soluble in benzene and chloroform. It is insoluble in water.

Uses of Cycloheptane

Cycloheptane is mainly used as a laboratory chemical for organic chemical analysis and as a raw material for organic synthesis. Due to its structural characteristics as a seven-membered cycloalkane without functional group substitutions, it is used as a nonpolar solvent or as a building block.

In the chemical industry, it is used as a nonpolar solvent and as a synthetic intermediate in the manufacture of chemicals and pharmaceuticals.

Characteristics of Cycloheptane

Cycloheptane is a seven-membered ring, but it does not have a planar structure, so it has a three-dimensional structure with several conformations. There are two stable conformations: twisted chair and twisted boat, with the twisted chair being the most stable.

The other conformations are chair, boat, and T3, which take on these structures in the transition state between stable conformations. The ring contraction reaction under the action of aluminum chloride leads to isomerization and the formation of methylcyclohexane.

It has a low flash point of 6°C and is highly flammable. Exposure to heat or flame poses a high risk of fire. It is highly reactive with oxygen-rich substances, such as strong oxidizers, and must be avoided in storage.

Types of Cycloheptane

Cycloheptane is generally sold as a reagent product for research and development. It is available in 1g, 5g, 25g, 25mL, etc., and is supplied in small and compact volumes that are easy to handle in the laboratory. It is handled as a reagent product that can be stored and transported at room temperature.

Cycloheptane is highly flammable, combustible, and toxic to the human body. 

Other Information on Cycloheptane

1. Synthesis of Cycloheptane

Methods for synthesizing cycloheptane include the reduction of the carbonyl group by clemencene reduction of cycloheptanone and cyclization using 1,6-dibromohexane and malonic acid diesters.

2. Safety Information on Cycloheptane

Cycloheptane is highly flammable, combustible, and highly hazardous. It is also toxic to the human body, causing drowsiness and dizziness. The vapors can cause eye irritation, and inhalation of large quantities may cause reduced ventilation.

When handling, it is important to keep the material away from ignition sources, such as heat, sparks, open flames, and hot objects, and to provide ventilation when in use. It is also necessary to use appropriate protective equipment, avoid inhalation of mists, vapors, and sprays, and avoid direct contact.

If contact with the human body occurs, the liquid should be removed promptly by removing clothing or running water. If inhaled, medical attention is required. In addition, when disposing of the product, it is required to outsource the work to a specialized waste disposal company licensed by the prefectural governor and dispose of the product appropriately.

What Is a CPLD?

A Complex Programmable Logic Device (CPLD) is a rewritable logic device with a relatively complex circuit structure.

CPLDs have made the development of products easier and less expensive than ever before.

Uses of CPLDs

CPLDs are widely used in the control boards of various consumer and industrial products, such as:

• Digital cameras and multifunction devices.
• Smartphones.
• In-vehicle controls and car navigation systems.
• Game consoles.

CPLDs are used in control circuits, particularly for the management of power circuits. They are often responsible for managing the order in which power is applied to circuits, voltage selection circuits, and other functions.

Principle of CPLDs

A CPLD consists of a block in which multiple programmable logic circuits are integrated and a wiring area that connects the different blocks. The block consists of three macrocells with AND-OR gate structures, a D-type flip-flop to hold one bit of information as either 0 or 1, and I/O pins for input and output.

The macrocell inputs digital signals from the Input pin and outputs signals to the Output pin with user-programmed logic circuitry. Internal primary data is stored in flip-flops.

The Routing Area is the connection between blocks and output data through one or more blocks.

Other Information about CPLDs

1. Differences between CPLDs and FPGAs

Field-Programmable Gate Arrays (FPGAs) are similar to CPLDs in that they use volatile memory, which means that circuit data is lost when power is removed.

CPLDs, on the other hand, use nonvolatile memory, such as EEPROM or flash memory, which retain circuit data. There is also a difference in scale.

FPGAs have tens of thousands of gates, while CPLDs have only a few thousand. Therefore, CPLDs are used to provide design data to FPGAs when power is turned on, while FPGAs are used to perform large-scale logic circuitry.

Additionally, latency varies depending on where the logic blocks are located, making it difficult for the FPGA to predict. In contrast, latency is easier for CPLDs to predict because the number of macrocells to be routed through them is fixed.

2. History of CPLDs

CPLDs were developed to replace TTL and CMOS logic devices about 30 years ago. At that time, circuits were constructed by combining general-purpose logic ICs with only NOT and AND functions.

The 7400 series from Texas Instruments (TI) is well known, but it is said that engineers at that time had to memorize hundreds of devices. The problem was that as circuits became more complex, dozens to hundreds of general-purpose logic ICs were required, resulting in huge board sizes.

As transistor miniaturization progressed, it became possible to realize thousands or tens of thousands of general-purpose logic ICs in a few LSIs, which accelerated the development of CPLDs.

3. The Process of Developing CPLDs

The development process for CPLD design is categorized into the following steps: logic design, logic synthesis, place and route, timing verification, and programming.

• Logic Design
  Circuit design, also known as RTL design, is performed using hardware description languages such as Verilog and VHDL.
• Logic Synthesis
  Converts a circuit expressed in a hardware description language into a netlist that can be implemented in a CPLD. The circuit description is interpreted and converted into logic expressions such as NOT and AND. At this point, optimization is also performed to improve the operating speed of the circuit and reduce the chip area.
• Place and Route
  This determines how the contents of the netlist are arranged inside the CPLD. The time it takes for the outputs of the combined circuitry to stabilize is calculated, and the output timing between signals is adjusted to mitigate variability.
• Timing Verification
  Define delay times for elements inside CPLDs and perform simulations.
• Programming
  Based on the final design, data generated from development tools is fed into the CPLD.

What Is Cyclobutadiene?

Cyclobutadiene (C4H4) is the simplest of the cyclic hydrocarbons containing a conjugated double bond.

In 1965, R. Pettit showed that cyclobutadiene could be liberated by reacting the iron carbonyl chain of cyclobutadiene with a tetravalent cerium salt.

The number of π-electrons is stable when it consists of six (4π+2), as in benzene.

Cyclobutadiene forms a square by sigma bonding and is unstable because it consists of 4 pi-electrons, making it anti-aromatic.

Uses of Cyclobutadiene

Cyclobutadiene is a molecule that cannot exist because of its anti-aromatic property, consisting of four carbon atoms.

Cyclobutadiene was elucidated to be unstable based on Hückel’s rule, but in the 1970s, the rectangular singlet cyclobutadiene was found to be the most stable structure.

In 2009, Prof. Sekiguchi et al. at the University of Tsukuba, in collaboration with Prof. Apeloig at the Israel Institute of Technology, succeeded for the first time in the world in optically observing cyclobutadiene in the triplet state.

What Is Cyclooctane?

Cyclooctane is an organic compound, a cycloalkane (alicyclic compound) with a saturated 8-membered ring structure.

Its molecular formula is C8H16 and its CAS number is 292-64-8. It has a molecular weight of 112.21, a melting point of 12-14°C, and a boiling point of 150°C. At room temperature, it is a clear colorless to brown liquid.

It has a camphor-like odor (however, its molecular structure is completely different from camphor, a component of camphor). It is soluble in ethanol and acetone, but hardly soluble in water. Its solubility in water is 7.90 mg/L. It has a density of 0.836 g/mL (20°C) and a flash point of 30°C.

Uses of Cyclooctane

Cyclooctane is mainly used as a solvent and reagent. It is also useful as a synthetic intermediate, for example, as an intermediate in the manufacture of plastics, fibers, adhesives, and coatings.

Academically, it is also a representative of saturated 8-membered ring compounds, and its stereoconformation has been extensively studied using computational chemistry techniques.

Properties of Cyclooctane

The chemistry of cyclooctane includes combustion reactions and free radical halogenation reactions, which are typical of saturated hydrocarbons. For example, cyclooctane can be aminated by using a peroxide, such as dicumyl peroxide and nitrobenzene.

Although stable under normal storage conditions, in storage it should be kept away from high temperatures, direct sunlight, heat, flames, sparks, and static electricity. Mixture with strong oxidizing agents is also strictly prohibited. Hazardous decomposition products include carbon monoxide and carbon dioxide.

Types of Cyclooctane

Cyclooctane is sold primarily as a reagent product for research and development. The volume types include 25 mL, 500 mL, and others. It is a reagent that can be handled at room temperature. However, it has a low flash point and is a compound regulated by the Fire Service Law, so it must be handled in compliance with the law.

Cyclooctane d-16, in which all hydrogen atoms are replaced with deuterium, is also available as a reagent product. This substance is used as a heavy solvent for NMR analysis. It is expensive due to the large number of deuterium atoms and is used in special cases where other solvents cannot be used.

Other Information on Cyclooctane

1. Synthesis of Cyclooctane

Cyclooctane can be synthesized by hydrogenating Cyclooctadiene to saturated hydrocarbons. Compounds such as the intermediate 1,5-cyclooctadiene are first synthesized by dimerization of butadiene using a nickel(0) complex such as bis(cyclooctadiene)nickel as a catalyst.

Cyclooctane is synthesized by hydrogenation of cyclooctadiene by catalytic reduction. 

2. Conformation of Cyclooctane

Cyclooctane is a cycloalkane with a very complex stereochemistry due to the presence of several stereoconfigurations with similar energies. The conformations include boat-chair, canned, bucket, boat-boat, twisted boat-chair, and twisted chair-chair. The most stable configuration is reported to be boat-ice. 

3. Regulatory Information and Precautions for Handling Cyclooctane

Cyclooctane has a low flash point of 30°C and is a highly flammable liquid and vapor.

Fire prevention includes the use of explosion-proof electrical equipment, ventilation equipment, and lighting equipment, the use of spark-proof tools, and measures to prevent electrostatic discharge. In addition, protective equipment such as protective gloves, protective clothing, protective glasses, and protective masks must be worn when handling this substance.

If it adheres to the skin, it is necessary to remove all contaminated clothing immediately and wash the skin under running water. Also, if swallowed and enters the respiratory tract, it may be life-threatening and extremely dangerous.

What Is Glutaraldehyde?

Glutaraldehyde is an organic compound classified as a dialdehyde compound.

Its molecular formula is C5H8O2, and in accordance with IUPAC nomenclature, it is called 1,5-pentanedial.

It has a molecular weight of 100.12, a melting point of -14°C, and a boiling point of 71-72°C. It is a colorless or slightly pale yellow liquid at room temperature. It has a pungent odor. The substance is readily soluble in water, alcohol, and acetone.

It is also highly toxic and irritating, and the development of chemical hypersensitivity has been suggested. Because of these toxic properties, glutaraldehyde is a compound subject to various laws and regulations. 

Uses of Glutaraldehyde

Glutaraldehyde is used as a fixing solution for electron microscopes, as a leather tanning agent, as a fixing agent for paper and plastic, as a cross-linking agent (hardener) for photographic gelatin, and as a developing agent for radiographic photographs.

Because it has two aldehyde groups, it has strong fixing power and is excellent in maintaining the morphology of microstructures. However, because of its weak permeability in tissues, tissue samples are usually limited to 1 mm square. Furthermore, it requires cooling at 4°C for about 1-2 hours.

Because of its strong sterilizing power, it is used as a chemical sterilization and disinfection agent for medical instruments, equipment, and devices, such as endoscopes and surgical instruments. 2% glutaraldehyde solution and 20% glutaraldehyde solution are approved drugs for medical use, and are effective against almost all bacteria, fungi, spores, and viruses. They are effective against almost all bacteria, fungi, spores, and viruses.

In addition, it is also used as an algaecide for cooling towers and as a disinfectant for poultry houses and poultry farming equipment.

Characteristics of Glutaraldehyde

Glutaraldehyde is relatively unstable when heated and can polymerize. It can also be converted to glutaric acid through oxidation reactions.

Types of Glutaraldehyde

Glutaraldehyde products currently on the market include medical-use pharmaceuticals and reagents for research and development.

As mentioned above, medical-use pharmaceutical products are used as disinfectants for medical instruments, and include 2% glutaraldehyde solution, 20% glutaraldehyde solution, and other types.

Reagent products for research and development are also sold mainly as aqueous solutions, and are available in concentrations of 25% and 50%. The capacities include 25mL, 500mL, 1L, 3L, etc., and are provided in volumes that are easy to handle in the laboratory.

Other Information on Glutaraldehyde

1. Action and Reactivity of Glutaraldehyde

Glutaraldehyde’s action as a fixing and sterilizing solution is due to the high reactivity of its aldehyde groups. When used as a fixing solution in the biological field, the main reaction occurs with the ε-amino group of the lysine residue of proteins, but reactions also occur with the α-amino group and SH group.

These will form intermolecular cross-links and function as a fixing solution. In this case, a single molecule of glutaraldehyde does not form a cross-link by itself, but rather a polymer such as a dimer or trimer formed in aqueous solution or an unsaturated aldehyde formed by aldol condensation is considered to be the reaction-active species.

The mechanism of action of glutaraldehyde when used as a fungicide is believed to be the alkylation of the amino group of the cytoplasm by the aldehyde group of glutaraldehyde.

2. Toxicity of Glutaraldehyde

Glutaraldehyde is highly toxic and irritating, and the following toxicities have been reported. Although no clear carcinogenicity has been reported, the occurrence of chemical hypersensitivity similar to formaldehyde has been noted.

• Harmful if swallowed
• Harmful in contact with skin
• May cause allergy, asthma, or breathing difficulties if inhaled
• May cause serious skin irritation and eye damage
• May cause allergic skin reactions
• Harmful to central nervous system
• May cause respiratory irritation
• May cause airway damage due to long-term or repeated exposure

What Is Glyceric Acid?

Glyceric acid is an organic compound with a molecular weight of 106.08 and molecular formula C3H6O4.

It is another name for 2,3-dihydroxypropionic acid, a hydroxycarboxylic acid.

Uses of Glyceric Acid

D-glyceric acid is an organic acid found naturally in plants and is a compound found in trace amounts in a variety of plants, including tobacco, artichokes, apples, and nuts.

In addition, glyceric acid has been reported to have multiple biological activities, such as improving liver function and promoting ethanol metabolism. However, research on its functions and applications is lacking. Recent studies have shown promise as a raw material for polymers and organic materials, including the following:

Diacylglyceric Acid
In which the hydroxyl group of glyceric acid is acylated to introduce, for example, linolenic acid or palmitic acid, is expected to be used as a composition for cosmetics and skin care products. In addition, monoacylglyceric acid has been shown to be a surfactant with minimal skin irritation.

Glycosyl Glyceric Acid
Obtained by reacting glyceric acid with sugar, has been found to be less irritating to skin cells and protective against external stress, and is expected to be a new material that can be applied to skin and hair care products.

As mentioned above, acyl and glucosyl derivatives of glyceric acid have been reported to have excellent surfactant and biomolecular protection functions. On the other hand, glyceric acid alone, without derivatives, has been shown to have a cell activating function (calcium glycerate activates ethanol-damaged stomach cells), and is expected to be used in dietary supplements.

In addition, glyceric acid has two hydroxyl groups and a carboxyl group with different reactivities, making it easy to polymerize, and it is expected to be developed into a biodegradable polymer.

Properties of Glyceric Acid

Glyceric acid is one of the hydroxycarboxylic acids and is represented by the chemical formula HOCH2(OH)COOH, but because it has an asymmetric carbon, there are two optical isomers, D- and L-body.

The D- and L-bodies are mirror images of each other, like the right and left hands, which cannot be superimposed on each other; D-glyceric acid and L-glyceric acid have the same chemical properties but different biological actions.

DL-glyceric acid, a mixture of D-glyceric acid and L-glyceric acid, is a syrupy liquid that is soluble in water, ethanol and acetone, but insoluble in ether and benzene. It is often sold as a solution of glyceric acid.

Other Information on Glyceric Acid

How Glyceric Acid Is Produced

Glyceric Acid is an important raw material as described above, but industrial production methods have not been established and it is expensive. Therefore, technological development is underway to produce glyceric acid from inexpensive glycerin.

It is widely known that DL-glyceric acid can be produced by chemical or biological oxidation of glycerin. However, it is necessary to control the oxidation of multiple hydroxyl groups in the molecule. Therefore, technological development for highly selective oxidation by various methods is underway.

It is known that D-glyceric acid and L-glyceric acid can be selectively obtained by racemization of DL-glyceric acid through the successful use of microorganisms. However, since the number of processes increases, a method to directly obtain the D-body using microorganisms is also being studied.

As a production method other than oxidation of glyceric acid, a method by hydrolysis of 2,3-dibromopropionic acid is also known.

Glyceric acid obtained by fermentation production is D-body, whereas L-glyceric acid is a promising raw material for synthesis of L-sugar derivatives that can be applied to pharmaceuticals and other products. Therefore, the development of a new process for the production of L-glycerynic acid is also underway. The development of a microbial process that can control the optical isomerism of glyceric acid has made it possible to obtain D-glyceric acid with a high L content.