|
M-Xylylenediamine
''m''-Xylylenediamine is an organic compound with the formula C6H4(CH2NH2)2. A colorless oily liquid, it is produced by hydrogenation of isophthalonitrile. Uses and reactions ''m''-Xylylenediamine (MXDA) is used in a variety of industrial applications including amine based curing agents for epoxy resins which may then be formulated into coatings, adhesives, sealants, and elastomers. ''m''-Xylylenediamine undergoes to Sommelet reaction to give isophthalaldehyde. Hazards Exposure to ''m''-xylylenediamine may occur by inhalation, skin contact, eye exposure, or ingestion. It can cause chemical burns, tissue damage, delayed pulmonary edema, shock, and skin sensitization. Symptoms of inhalation include a burning sensation in the respiratory tract, cough, sore throat, labored breathing, and dyspnea (shortness of breath). It is also flammable and produces toxic fumes when burned. ''m''-Xylylenediamine reacts with acids, acid chlorides, and acid anhydride An acid anhydride is a type of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sommelet Reaction
The Sommelet reaction is an organic reaction in which a benzyl halide is converted to an aldehyde by action of hexamine and water. : One example, thiophene-2-carboxaldehyde is prepared by the reaction of hexamine with 2-chloromethylthiophene. The reaction is formally an oxidation of the carbon. Reaction mechanism and scope The benzyl halide 1 reacts with hexamine to a quaternary ammonium salt 3, each time just alkylating one nitrogen atom. Then the benzylammonium undergoes an acid-catalyzed hydrolysis process. : Depending on the hydrolysis conditions, the hexamine unit might instead break apart, leaving a benzyl amine (the Delépine reaction). The reaction can also be applied to the oxidation of benzylic amines. In this way, ''m''-xylylenediamine can be converted to isophthalaldehyde Isophthalaldehyde is an organic compound with the formula C6H4(CHO)2. It is one of three isomers of benzene di carbaldehyde, a reduced analog of phthalic acid. It is colorless, although c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isophthalonitrile
Isophthalonitrile is an organic compound with the formula C6H4(CN)2. Two other isomers exist, phthalonitrile and terephthalonitrile. All three isomers are produced commercially by ammoxidation of the corresponding xylene isomers. Isophthalonitrile is a colorless or white solid with low solubility in water.{{Ullmann, doi=10.1002/14356007.a17_363, title=Nitriles, year=2000, last1=Pollak, first1=Peter, last2=Romeder, first2=Gérard, last3=Hagedorn, first3=Ferdinand, last4=Gelbke, first4=Heinz-Peter, isbn=3527306730 Hydrogenation of isophthalonitrile affords m-xylylenediamine, a curing agent in epoxy resins and a component of some urethanes. Safety LD50 In toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a toxin, radiation, or pathogen. The value of LD50 for a substance is the ... (rat, oral) is 288 mg/kg. References Benzonitriles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprise the discipline known as organic chemistry. For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts), along with a few other exceptions (e.g., carbon dioxide, hydrogen cyanide), are not classified as organic compounds and are considered inorganic. Other than those just named, little consensus exists among chemists on precisely which carbon-containing compounds are excluded, making any rigorous definition of an organic compound elusive. Although organic compounds make up only a small percentage of Earth's crust, they are of central importance because all known life is based on organic compounds. Living t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid Chloride
In organic chemistry, an acyl chloride (or acid chloride) is an organic compound with the functional group . Their formula is usually written , where R is a side chain. They are reactive derivatives of carboxylic acids (). A specific example of an acyl chloride is acetyl chloride, . Acyl chlorides are the most important subset of acyl halides. Nomenclature Where the acyl chloride moiety takes priority, acyl chlorides are named by taking the name of the parent carboxylic acid, and substituting ''-yl chloride'' for ''-ic acid''. Thus: : : When other functional groups take priority, acyl chlorides are considered prefixes — ''chlorocarbonyl-'': : Properties Lacking the ability to form hydrogen bonds, acyl chlorides have lower boiling and melting points than similar carboxylic acids. For example, acetic acid boils at 118 °C, whereas acetyl chloride boils at 51 °C. Like most carbonyl compounds, infrared spectroscopy reveals a band near 1750 cm−1. The simplest s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequence of database operations that satisfies the ACID properties (which can be perceived as a single logical operation on the data) is called a ''transaction''. For example, a transfer of funds from one bank account to another, even involving multiple changes such as debiting one account and crediting another, is a single transaction. In 1983, Andreas Reuter and Theo Härder coined the acronym ''ACID'', building on earlier work by Jim Gray who named atomicity, consistency, and durability, but not isolation, when characterizing the transaction concept. These four properties are the major guarantees of the transaction paradigm, which has influenced many aspects of development in database systems. According to Gray and Reuter, the IBM Informa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dyspnea
Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity", and recommends evaluating dyspnea by assessing the intensity of its distinct sensations, the degree of distress and discomfort involved, and its burden or impact on the patient's activities of daily living. Distinct sensations include effort/work to breathe, chest tightness or pain, and "air hunger" (the feeling of not enough oxygen). The tripod position is often assumed to be a sign. Dyspnea is a normal symptom of heavy physical exertion but becomes pathological if it occurs in unexpected situations, when resting or during light exertion. In 85% of cases it is due to asthma, pneumonia, cardiac ischemia, interstitial lung disease, congestive heart failure, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Labored Breathing
Labored respiration or labored breathing is an abnormal respiration characterized by evidence of increased effort to breathe, including the use of accessory muscles of respiration, stridor, grunting, or nasal flaring. Classification Labored breathing is distinguished from shortness of breath or ''dyspnea'', which is the sensation of respiratory distress rather than a physical presentation. Still, many simply define dyspnea as ''difficulty in breathing'' without further specification, which may confuse it with e.g. labored breathing or tachypnea (rapid breathing). Labored breathing has occasionally been included in the definition of dyspnea as well. However, in the standard definition, these related signs may be present at the same time, but do not necessarily have to be. For instance, in respiratory arrest by a primary failure in respiratory muscles the patient, if conscious, may experience dyspnea, yet without having any labored breathing or tachypnea. The other way around, labore ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sore Throat
Sore throat, also known as throat pain, is pain or irritation of the throat. Usually, causes of sore throat include * viral infections * group A streptococcal infection (GAS) bacterial infection * pharyngitis (inflammation of the throat) * tonsillitis (inflammation of the tonsils), or dehydration, which leads to the throat drying up. The majority of sore throats are caused by a virus, for which antibiotics are not helpful. A strong association between antibiotic misuse and antibiotic resistance has been shown. Symptoms of sore throat include: * a scratchy sensation * pain during swallowing * discomfort while speaking * a burning sensation * swelling in the neck For sore throat caused by bacteria (GAS), treatment with antibiotics may help the person get better faster, reduce the risk that the bacterial infection spreads, prevent retropharyngeal abscesses and quinsy, and reduce the risk of other complications such as rheumatic fever and rheumatic heart disease. In most develop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cough
A cough is a sudden expulsion of air through the large breathing passages that can help clear them of fluids, irritants, foreign particles and microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three phases: an inhalation, a forced exhalation against a closed glottis, and a violent release of air from the lungs following opening of the glottis, usually accompanied by a distinctive sound. Frequent coughing usually indicates the presence of a disease. Many viruses and bacteria benefit, from an evolutionary perspective, by causing the host to cough, which helps to spread the disease to new hosts. Most of the time, irregular coughing is caused by a respiratory tract infection but can also be triggered by choking, smoking, air pollution, asthma, gastroesophageal reflux disease, post-nasal drip, chronic bronchitis, lung tumors, heart failure and medications such as angiotensin-converting-enzyme inhibitors (ACE inhibitors). Treatment should t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shock (circulatory)
Shock is the state of insufficient blood flow to the tissues of the body as a result of problems with the circulatory system. Initial symptoms of shock may include weakness, fast heart rate, fast breathing, sweating, anxiety, and increased thirst. This may be followed by confusion, unconsciousness, or cardiac arrest, as complications worsen. Shock is divided into four main types based on the underlying cause: low volume, cardiogenic, obstructive, and distributive shock. Low volume shock, also known as hypovolemic shock, may be from bleeding, diarrhea, or vomiting. Cardiogenic shock may be due to a heart attack or cardiac contusion. Obstructive shock may be due to cardiac tamponade or a tension pneumothorax. Distributive shock may be due to sepsis, anaphylaxis, injury to the upper spinal cord, or certain overdoses. The diagnosis is generally based on a combination of symptoms, physical examination, and laboratory tests. A decreased pulse pressure (systolic blood pressure m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skin Sensitization
Autosensitization dermatitis presents with the development of widespread dermatitis or dermatitis distant from a local inflammatory focus, a process referred to as autoeczematization. See also * Id reaction * List of cutaneous conditions Many skin conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against t ... References External links Eczema {{Cutaneous-condition-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Edema
Pulmonary edema, also known as pulmonary congestion, is excessive edema, liquid accumulation in the parenchyma, tissue and pulmonary alveolus, air spaces (usually alveoli) of the lungs. It leads to impaired gas exchange and may cause hypoxemia and respiratory failure. It is due to either failure of the left ventricle of the heart to remove oxygenated blood adequately from the pulmonary circulation (cardiogenic pulmonary edema), or an injury to the lung parenchyma, lung tissue directly or blood vessels of the lung (non-cardiogenic pulmonary edema). Treatment is focused on three aspects: firstly improving respiratory function, secondly, treating the underlying cause, and thirdly preventing further damage and assuring full recovery to the lung. Pulmonary edema, especially when sudden (acute), can lead to respiratory failure or cardiac arrest due to Hypoxia (medical), hypoxia. It is a cardinal feature of congestive heart failure. The term edema is from the Greek language, Greek (''oi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
