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Acetanilide
Acetanilide is an odourless solid chemical of leaf or flake-like appearance. It is also known as ''N''-phenylacetamide, acetanil, or acetanilid, and was formerly known by the trade name Antifebrin. Preparation and properties Acetanilide can be produced by reacting acetic anhydride with aniline: :C6H5NH2 + (CH3CO)2O → C6H5NHCOCH3 + CH3COOH The preparation used to be a traditional experiment in introductory organic chemistry lab classes, but it has now been widely replaced by the preparation of either paracetamol or aspirin, both of which teach the same practical techniques (especially recrystallization of the product) but which avoid the use of aniline, a suspected carcinogen. Acetanilide is slightly soluble in water, and stable under most conditions. Pure crystals are plate shaped and appear colorless, white, or in between. Applications Acetanilide is used as an inhibitor of hydrogen peroxide decomposition and is used to stabilize cellulose ester varnishes. It has also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetanilide Crystals
Acetanilide is an odourless solid chemical of leaf or flake-like appearance. It is also known as ''N''-phenylacetamide, acetanil, or acetanilid, and was formerly known by the trade name Antifebrin. Preparation and properties Acetanilide can be produced by reacting acetic anhydride with aniline: :C6H5NH2 + (CH3CO)2O → C6H5NHCOCH3 + CH3COOH The preparation used to be a traditional experiment in introductory organic chemistry lab classes, but it has now been widely replaced by the preparation of either paracetamol or aspirin, both of which teach the same practical techniques (especially recrystallization of the product) but which avoid the use of aniline, a suspected carcinogen. Acetanilide is slightly soluble in water, and stable under most conditions. Pure crystals are plate shaped and appear colorless, white, or in between. Applications Acetanilide is used as an inhibitor of hydrogen peroxide decomposition and is used to stabilize cellulose ester varnishes. It has also f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paracetamol
Paracetamol, also known as acetaminophen, is a medication used to treat fever and mild to moderate pain. Common brand names include Tylenol and Panadol. At a standard dose, paracetamol only slightly decreases body temperature; it is inferior to ibuprofen in that respect, and the benefits of its use for fever are unclear. Paracetamol may relieve pain in acute mild migraine but only slightly in episodic tension headache. However, the aspirin/paracetamol/caffeine combination helps with both conditions where the pain is mild and is recommended as a first-line treatment for them. Paracetamol is effective for post- surgical pain, but it is inferior to ibuprofen. The paracetamol/ibuprofen combination provides further increase in potency and is superior to either drug alone. The pain relief paracetamol provides in osteoarthritis is small and clinically insignificant. The evidence in its favor for the use in low back pain, cancer pain, and neuropathic pain is insufficient. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photographic Developer
In the processing of photographic films, plates or papers, the photographic developer (or just developer) is one or more chemicals that convert the latent image to a visible image. Developing agents achieve this conversion by reducing the silver halides, which are pale-colored, into silver metal, which is black (when a fine particle).Karlheinz Keller et al. ''Photography'' in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2005, Wiley-VCH, Weinheim. The conversion occurs within the gelatine matrix. The special feature of photography is that the developer acts more quickly on those particles of silver halides that have been exposed to light. Paper left in developer will eventually reduce all the silver halides and turn black. Generally, the longer a developer is allowed to work, the darker the image. Chemical composition of developers The developer typically consists of a mixture of chemical compounds prepared as an aqueous solution. For black-and-white photography, three ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenacetin
Phenacetin (acetophenetidin, ''N''-(4-ethoxyphenyl)acetamide) is a pain-relieving and fever-reducing drug, which was widely used following its introduction in 1887. It was withdrawn from medicinal use as dangerous from the 1970s (e.g., withdrawn in Canada in 1973, and by the U.S. Food and Drug Administration in 1983). History Phenacetin was introduced in 1887 in Elberfeld, Germany by German company Bayer, and was used principally as an analgesic; it was one of the first synthetic fever reducers to go on the market. It is also known historically to be one of the first non- opioid analgesics without anti-inflammatory properties. Although paracetamol was produced earlier, a historical accident saw it ignored after Joseph von Mering's assessment. Prior to World War One, Britain imported phenacetin from Germany. During the war, a team including Jocelyn Field Thorpe and Martha Annie Whiteley developed a synthesis in Britain. Known mechanism of action Phenacetin's analgesic effects a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analgesic
An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It is typically used to induce cooperation with a medical procedure. Analgesics are conceptually distinct from anesthetics, which temporarily reduce, and in some instances eliminate, sensation, although analgesia and anesthesia are neurophysiologically overlapping and thus various drugs have both analgesic and anesthetic effects. Analgesic choice is also determined by the type of pain: For neuropathic pain, traditional analgesics are less effective, and there is often benefit from classes of drugs that are not normally considered analgesics, such as tricyclic antidepressants and anticonvulsants. Various analgesics, such as many NSAIDs, are available over the counter in most countries, whereas various others are prescription drugs owi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Inhibitor
A reaction inhibitor is a substance that decreases the rate of, or prevents, a chemical reaction. A catalyst, in contrast, is a substance that increases the rate of a chemical reaction. Examples * Added acetanilide slows the decomposition of drug-store hydrogen peroxide solution, inhibiting the reaction 2 → 2 + , which is catalyzed by heat, light, and impurities.The decomposition of hydrogen peroxide Inhibition of a catalyst An inhibitor can reduce the effectiveness of a catalyst in a catalysed reaction (either a non-biological catalyst or an enzyme). E.g., if a compound is so similar to (one of) the reactants that it can bind to the active site of a catalyst but does not undergo a catalytic reaction then that catalyst molecule cannot perform its job because the active site is occupied. When the inhibitor is released, the catalyst is again available for reaction. Inhibition and catalyst poisoning Inhibition should be distinguished from catalyst poisoning. An inhibitor only hin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rubber
Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and Indonesia are three of the leading rubber producers. Types of polyisoprene that are used as natural rubbers are classified as elastomers. Currently, rubber is harvested mainly in the form of the latex from the rubber tree (''Hevea brasiliensis'') or others. The latex is a sticky, milky and white colloid drawn off by making incisions in the bark and collecting the fluid in vessels in a process called "tapping". The latex then is refined into the rubber that is ready for commercial processing. In major areas, latex is allowed to coagulate in the collection cup. The coagulated lumps are collected and processed into dry forms for sale. Natural rubber is used extensively in many applications and products, either alone or in combination ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall of green plants, many forms of algae and the oomycetes. Some species of bacteria secrete it to form biofilms. Cellulose is the most abundant organic polymer on Earth. The cellulose content of cotton fiber is 90%, that of wood is 40–50%, and that of dried hemp is approximately 57%. Cellulose is mainly used to produce paperboard and paper. Smaller quantities are converted into a wide variety of derivative products such as cellophane and rayon. Conversion of cellulose from energy crops into biofuels such as cellulosic ethanol is under development as a renewable fuel source. Cellulose for industrial use is mainly obtained from wood pulp and cotton. Some animals, particularly ruminants and termites, can digest cellulose wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are fatty acid esters of glycerol; they are important in biology, being one of the main classes of lipids and comprising the bulk of animal fats and vegetable oils. Esters typically have a pleasant smell; those of low molecular weight are commonly used as fragrances and are found in essential oils and pheromones. They perform as high-grade solvents for a broad array of plastics, plasticizers, resins, and lacquers, and are one of the largest classes of synthetic lubricants on the commercial market. Polyesters are important plastics, with monomers linked by ester moieties. Phosphoesters form the backbone of DNA molecules. Nitrate esters, such as nitroglycerin, are known for their explosive properties. '' Nomenclature Etymology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varnish
Varnish is a clear transparent hard protective coating or film. It is not a stain. It usually has a yellowish shade from the manufacturing process and materials used, but it may also be pigmented as desired, and is sold commercially in various shades. Varnish is primarily used as a wood finish where, stained or not, the distinctive tones and grains in the wood are intended to be visible. Varnish finishes are naturally glossy, but satin/semi-gloss and flat sheens are available. History The word "varnish" comes from Mediaeval Latin ''vernix'', meaning odorous resin, itself derived from Middle Greek ''berōnikón'' or ''beroníkē'', meaning amber or amber-colored glass. A false etymology traces the word to the Greek '' Berenice'', the ancient name of modern Benghazi in Libya, where the first varnishes in the Mediterranean area were supposedly used and where resins from the trees of now-vanished forests were sold. Early varnishes were developed by mixing resin—pine sap, fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Society Of Chemistry
The Royal Society of Chemistry (RSC) is a learned society (professional association) in the United Kingdom with the goal of "advancing the chemical sciences". It was formed in 1980 from the amalgamation of the Chemical Society, the Royal Institute of Chemistry, the Faraday Society, and the Society for Analytical Chemistry with a new Royal Charter and the dual role of learned society and professional body. At its inception, the Society had a combined membership of 34,000 in the UK and a further 8,000 abroad. The headquarters of the Society are at Burlington House, Piccadilly, London. It also has offices in Thomas Graham House in Cambridge (named after Thomas Graham, the first president of the Chemical Society) where ''RSC Publishing'' is based. The Society has offices in the United States, on the campuses of The University of Pennsylvania and Drexel University, at the University City Science Center in Philadelphia, Pennsylvania, in both Beijing and Shanghai, China and in Ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camphor
Camphor () is a waxy, colorless solid with a strong aroma. It is classified as a terpenoid and a cyclic ketone. It is found in the wood of the camphor laurel (''Cinnamomum camphora''), a large evergreen tree found in East Asia; and in the kapur tree ( ''Dryobalanops'' sp.), a tall timber tree from South East Asia. It also occurs in some other related trees in the laurel family, notably ''Ocotea usambarensis''. Rosemary leaves ('' Rosmarinus officinalis'') contain 0.05 to 0.5% camphor, while camphorweed (''Heterotheca'') contains some 5%. A major source of camphor in Asia is camphor basil (the parent of African blue basil). Camphor can also be synthetically produced from oil of turpentine. The compound is chiral, existing in two possible enantiomers as shown in the structural diagrams. The structure on the left is the naturally occurring (+)-camphor ((1''R'',4''R'')-bornan-2-one), while its mirror image shown on the right is the (−)-camphor ((1''S'',4''S'')-bornan-2-one) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
